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Spermatogonial stem cells (SSCs) are unique with an important role in the transmission of genetic information to the next generation. Thus, they play an important role for the production of interspecies germ line chimeras. Therefore, the objective of this study was to produce chimera through the intraperitoneal transplantation of Caspian brown trout SSCs into newly-hatched rainbow trout. Spermatogonial cell were isolated from the testes of 8-month-old Caspian brown trout through enzymatic digestion. The spermatogonial cell suspension was enriched using differential plating technique to remove testicular somatic cells. After culturing for 48 h in L15 supplemented with 10% serum, suspended cells were collected and stained with the fluorescent membrane dye PKH26. The stained cells were intraperitoneally transplanted into triploid rainbow trout hatchlings. At 15 and 30 days after transplantation, the recipients were investigated under a fluorescent microscope. The gonads of recipients were dissected for molecular analysis at 180 days after transplantation. Transplanted spermatogonial cells migrated toward and incorporated into recipient genital ridges. The presence of the Caspian brown trout genetic material was confirmed by PCR in 41.4% of the rainbow trout testes. These results demonstrated for the first time that the interspecies spermatogonial transplantation was successful in rainbow trout and that the somatic microenvironment of the rainbow trout gonad can support the colonization and survival of intraperitoneally transplanted cells derived from a fish species belonging to a different genus. Therefore, the SSCs transplantation can be used as a tool for conservation of Caspian brown trout genetic resources.

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The aim of this paper is to investigate the growth of pitting corrosion in CUSTOM 450 stainless steel and to obtain strain values in growing pits at the maximum bending region. In this regard, a two-point bending specimen was made and subjected to a potentiostatic test under the potential of 350 mV_SCE in the 3.5 wt% sodium chloride solution. Then, the depth of the grown pits is calculated using Eddy Current device. By simulating a sample under the pitting corrosion in COMSOL Multiphysics software and matching its results with the results of the Eddy Current device, it was found that the simulation can largely replace the laboratory test. To calculate the tensile stress distribution in the cross section of the sample under pitting corrosion, the Laplace equation governing the sample was discretized. The same results were obtained by solving the discrete equations and comparing them with the results of COMSOL Multiphysics software. According to the results, the pit tends to grow superficially. This means that the surface growth of the pit is greater than its growth in the direction of depth. This is due to the fact that near the sample surface, tensile stress and electrical potential are high, as well as chemical reactions and corrosion in areas near to the pit surface.

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Hot corrosion and thermally grown oxide (TGO) formation are destructive factors in thermal barrier coatings (TBCs) that lead to coating failure under operational conditions. In the present study, the hot corrosion behavior and TGO evolution for TBCs whose Bond coat by deposited by atmospheric plasma spraying (APS) and high velocity oxygen fuel (HVOF) thermal spray methods were evaluated. Both types of coatings were subjected to cyclic hot corrosion testing at a temperature of 1100°C in the presence of molten salts of Na₂SO₄ and V₂O₅ under identical conditions. Subsequently, their microstructures were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD) images. Additionally, changes in TGO thickness were measured across different cycles using Image J software and SEM images. The results indicate that TBCs deposited using the HVOF method for the bond coat exhibit better performance compared to those deposited using the APS method. The results show that a phase change from tetragonal to monoclinic has occurred for zirconia with the penetration of corrosive salt melt and its reaction with the YSZ layer, and also with the depletion of yttria from the coating structure, YVO₄ reaction products have been formed for TBCs. The endurance of hot corrosion cycle of TBCs and the growth behavior of TGO show that the coatings whose interface layer is applied by the HVOF method show better performance than the APS method.