• Applied Microscopy
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• v.27 no.3
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• pp.333-346
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• 1997

The ischemia and reperfusion injury of the skeletal muscles is caused by generation of reactive oxygen during ischemia and reperfusion. It is well known that over 4 hours of ischemia injures the skeletal muscles irreversibly. The author has demonstrated the effects of SOD (superoxide dismutase), DMTU (dimethyl thiourea) and ischemic preconditioning on ultrastructural changes of the muscle fibers in the rectus femoris muscles after 4 hours of ischemia and 1 day and 3 days of reperfusion. A total of 72 healthy Sprague-Dawley rats weighing from 200 gm to 250 gm were used as experimental animals. Under urethane(1.15 g/kg, IP, 2 times) anesthesia, lower abdominal incision was done and the left common iliac artery was occluded by using vascular clamp for 4 hours. The left rectus femoris muscles were obtained at 1 and 3 days after the removal of vascular clamp. The SOD (15,000 unit/kg) or DMTU (500 mg/kg) were administered intraperitoneally at 1 hour before induction of ischemia. The ischemic preconditioned group underwent three episodes of 5 minutes occlusion and 5 minutes reperfusion followed by 4 hours of ischemia and 1 day and 3 days of reperfusion. The specimens were sliced into $1mm^3$ and prepared by routine methods for electron microscopic observation. All specimens were stained with uranyl acetate and lead citrate and then observed with Hitachi-600 transmission electron microscope. The results were as follows: 1. SOD or DMTU alone did not affect the ultrastructure of muscle fibers in the rectus femoris muscles. The electron density of mitochondrial matrix was decreased by ischemic preconditioning. 2. Dilated cisternae of sarcoplasmic reticulum, triad, mitochondria and the loss of myofilament in the sarcomere were observed in the 4 hours ischemia and 1 day reperfused rectus femoris muscles. Markedly changed sarcoplasmic reticulum, triad, disordered or loss of myofilament, indistinct A-band and I-band, and irregular electron lucent M -line and Z-line are seen in the 4 hours ischemia and 3 days reperfused rectus femoris muscles. 3. SOD reduced the changes of organelles in the muscle fibers of the 4 hours ischemia and 1 day reperfused rectus femoris muscles of the rats, but SOD did not affect the changes of muscle fibers in the 4 hours ischemia and 3 days reperfused muscles. On the other hand, DMTU markedly attenuated considerably the ultrastructural change of the 4 hours ischemia and 1 day or 3 days reperfused rectus femoris muscles. 4. By the ischemic preconditioning, the change was attenuated remarkably in the 4 hours ischemia and 1 day reperfused rectus femoris muscles. As the ischemic reperfused changes of muscle fibers were regenerated or recovered by ischemic preconditioning, the ultrastructures of them were similar to those of normal control in the 4 hours ischemia and 3 days reperfused rectus formoris muscles. Consequently, it is suggested that DMTU is stronger inhibitor to ischemic reperfused change than SOD. The ischemia and reperfusion-induced muscular damage is remarkably inhibited by ischemic preconditioning.

• Journal of Animal Science and Technology
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• v.46 no.2
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• pp.137-144
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• 2004

Algorithms for estimating breeding values on several categorical data by using latent variables with threshold conception were developed and showed. Thresholds on each categorical trait were estimated by Newton’s method via gradients and Hessian matrix. This algorithm was developed by way of expansion of bivariate analysis provided by Quaas(2001). Breeding values on latent variables of categorical traits and observations on linear traits were estimated by preconditioned conjugate gradient(PCG) method, which was known having a property of fast convergence. Example was shown by simulated data with two linear traits and a categorical trait with four categories(CE=calving ease) and a dichotomous trait(SB=Still Birth) in threshold animal mixed model(TAMM). Breeding value estimates in TAMM were compared to those in linear animal mixed model (LAMM). As results, correlation estimates of breeding values to parameters were 0.91${\sim}$0.92 on CE and 0.87${\sim}$0.89 on SB in TAMM and 0.72~0.84 on CE and 0.59~0.70 on SB in LAMM. As conclusion, PCG method for estimating breeding values on several categorical traits with linear traits were feasible in TAMM.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4348-4358
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• 2022

The thermal-hydraulics phenomena in a containment during an accident will necessarily include radiative heat transfer (i) within the gas mixture due to the high radiative absorption and emission of steam and (ii) between the gas mixture and the surrounding structures. The analysis of some previous PANDA experiments (PSI, Switzerland) demonstrated the importance of the proper modelling of radiation for the benefit of numerical simulations. These results together with dedicated scoping calculations conducted for the present experiments indicated that the radiative heat transfer is considerable, even for a very low amount of steam (≈2%). The H2P2 series conducted in the large-scale PANDA facility at the Paul-Scherrer-Institut (PSI) in the framework of the OECD/NEA HYMERES-2 project is intended to enhance the understanding of thermal radiation phenomena and to provide a benchmark for corresponding numerical simulations. Thus, the test matrix was tailored around the two opposite extremes: either gas compositions with small steam content such that radiative heat transfer phenomena can be neglected. Or gas mixtures containing larger amounts of steam, so that radiative heat transfer is expected to play a dominant role. The H2P2 series consists of 5 experiments designed to isolate the radiation phenomena from convective and diffusive effects as much as possible. One vessel with a diameter of 4 m and a height of 8 m was preconditioned with different mixtures of air / steam at room and elevated temperatures. This was followed by the build-up of a stable helium stratification at constant pressure in the upper part of the vessel. After that, helium was injected from the top into the vessel which leads to an increase of the vessel pressure and a corresponding elevation-dependent and transient rise of the gas temperature. It is shown that even the addition of small amounts of steam in the initial gas atmosphere considerably impacts the radiative heat transport throughout all phases of the experiments and markedly influences i) the monitored gas peak temperature, ii) the temperature history during the compression and iii) the following relaxation phase after the compression was stopped. These PANDA experiments are the first of its kind conducted in a large scale thermal-hydraulic facility.