Antioxidant Activity of Carnosine and Phytate: Application as Meat Preservatives

The antioxidant activity of carnosine and phytic acid was investigated using several model systems. Carnosine and phytic acid alone inhibited metal ion-catalyzed deoxyribose degradation. Carnosine strongly inhibited metal ion-catalyzed lipid peroxidation in liposomes and in ground beef homogenates. Phytic acid facilitated oxidation of Fe (II) to Fe (III), and it inhibited hemeprotein + H2O2-catalyzed lipid peroxidation in linoleic acid micelles. Antioxidant and color stabilizing effects of carnosine and phytate were investigated in a beef model system. Both compounds increased the rate of pH decline in pre-rigor beef muscle and stabilized fresh meat color by inhibiting metmyoglobin formation and lipid peroxidation in raw samples during storage at 4°C. Both compounds inhibited heme degradation and lipid peroxidation in cooked beef during storage at 4°C. Iron released from heme was strongly related to lipid peroxidation in cooked beef. Ascorbic acid inhibited metmyoglobin formation on the surface of ground beef patties but not in the bulk of the product. In contrast, camosine inhibited metmyoglobin formation and brown color development throughout the product. Carnosine increased cook yield and salt-soluble protein, but ascorbic acid had no effect on cook yield and decreased salt-soluble protein. Carnosine was more effective on inhibition of lipid peroxidation than was ascorbic acid. Phytate greatly enhanced water-holding capacity of raw and cooked meat in a dilute beef model system. Effects of 0.5% sodium phytate, sodium pyrophosphate, and sodium tripolyphosphate, along with 1% NaCl, on physicochemical properties of restructured raw and cooked beef were compared. In raw beef, the treatments with sodium phytate, sodium pyrophosphate, and sodium tripolyphosphate increased meat pH and salt-soluble protein level, and inhibited metmyoglobin formation and lipid peroxidation, compared to the control. In cooked beef, the treatments with sodium phytate, sodium pyrophosphate, and sodium tripolyphosphate increased bind strength, cooked yield, moisture level, and meat pH, and inhibited lipid peroxidation. The treatments with sodium pyrophosphate and sodium tripolyphosphate increased inorganic orthophosphate level in both raw and cooked beef, compared to sodium phytate and the control. These results indicate that carnosine and phytate can be used as meat preservatives for extending shelf-life and enhancing water-holding capacity of meat and meat products

Different Environmental Conditions in Genetic Algorithm

We propose an extended genetic algorithm (GA) with different local environmental conditions. Genetic entities, or configurations, are put on nodes in a ring structure, and location-dependent environmental conditions are applied for each entity. Our GA is motivated by the geographic aspect of natural evolution: Geographic isolation reduces the diversity in a local group, but at the same time, can enhance intergroup diversity. Mating of genetic entities across different environments can make it possible to search for broad area of the fitness landscape. We validate our extended GA for finding the ground state of three-dimensional spin-glass system and find that the use of different environmental conditions makes it possible to find the lower-energy spin configurations at relatively shorter computation time. Our extension of GA belongs to a meta-optimization method and thus can be applied for a broad research area in which finding of the optimal state in a shorter computation time is the key problem.Comment: 14 pages, 4 figure

Continuity of the Explosive Percolation Transition

The explosive percolation problem on the complete graph is investigated via extensive numerical simulations. We obtain the cluster-size distribution at the moment when the cluster size heterogeneity becomes maximum. The distribution is found to be well described by the power-law form with the decay exponent $\tau = 2.06(2)$, followed by a hump. We then use the finite-size scaling method to make all the distributions at various system sizes up to $N=2^{37}$ collapse perfectly onto a scaling curve characterized solely by the single exponent $\tau$. We also observe that the instant of that collapse converges to a well-defined percolation threshold from below as $N\rightarrow\infty$. Based on these observations, we show that the explosive percolation transition in the model should be continuous, contrary to the widely-spread belief of its discontinuity.Comment: Some corrections during the revie

Use of mineral trioxide aggregrate in the non-surgical repair of perforating invasive cervical resorption

Mineral trioxide aggregate (MTA) has shown potential as a repair material for perforations. This clinical case demonstrates that when MTA was used as a repair material for root perforation due to invasive cervical resorption, the tooth was well in function for 27 months. Both clinical and radiographic follow-up showed a stable condition without any probing defect, ongoing root resorption, or apical pathosis

Generalized gravity model for human migration

The gravity model (GM) analogous to Newton's law of universal gravitation has successfully described the flow between different spatial regions, such as human migration, traffic flows, international economic trades, etc. This simple but powerful approach relies only on the 'mass' factor represented by the scale of the regions and the 'geometrical' factor represented by the geographical distance. However, when the population has a subpopulation structure distinguished by different attributes, the estimation of the flow solely from the coarse-grained geographical factors in the GM causes the loss of differential geographical information for each attribute. To exploit the full information contained in the geographical information of subpopulation structure, we generalize the GM for population flow by explicitly harnessing the subpopulation properties characterized by both attributes and geography. As a concrete example, we examine the marriage patterns between the bride and the groom clans of Korea in the past. By exploiting more refined geographical and clan information, our generalized GM properly describes the real data, a part of which could not be explained by the conventional GM. Therefore, we would like to emphasize the necessity of using our generalized version of the GM, when the information on such nongeographical subpopulation structures is available.Comment: 14 pages, 6 figures, 2 table