Friction stir welding (FSW) parameters, such as tool material, tool geometry, tilt angle, tool rotational speed, welding speed, and axial force play a major role in the weld quality of titanium alloys. Because of excessive erosion, tool material and geometry play the main roles in FSW of titanium alloys. Therefore, in the present work for the first time, tool material and geometry, tool tilt angle, cooling system and shielding gas effects on macrostructure, microstructure, and mechanical properties of pure titanium weld joint were investigated. Result of this research shows that Ti can be joined by the FSW, using a tool with a shoulder made of tungsten (W) and simple pin made of tungsten carbide (WC). The best conditions for welding were use of compressed air as a cooling system, tool tilt angle of 1°, and a stream of Argon as a shielding medium. Investigation on mechanical properties shows that the tensile strength and the yield strength of the welded joint in the best case could be similar to the corresponding strengths of the base metal.
In the present article, the effect of friction stir welding (FSW) parameters on the weldability and the characteristics of dissimilar weld of aluminum alloys, called AA2024-T4 and AA7075-O are investigated. A number of FSW experiments are carried out to obtain high-quality welds by adjusting the rotational and welding speeds. The weldability and blending of two materials are evaluated by using the macrostructural analysis to observe whether making a notch in a threaded cylindrical tool will lead to a better blend rather than the threaded taper tool or it will have no effects. The mechanical properties of the welds are studied through microhardness distribution and tensile tests. Furthermore, the microstructure analysis is performed to study the influence of the pin profile and the rotational speed on the grain size. Moreover, in the present study, one of the most major goals is to obtain high-quality welds by spending as little expenditure as possible. Therefore, it prevents using complicated and insupportable high welding speed equipments.
Background. The aim of this study was to determine the correlation between MSI and sporadic colorectal cancer in Guilan province, North part of Iran.
Materials and Methods. A total of 96 patients who underwent resection for sporadic colorectal cancer in Guilan province were studied. No patients had positive family history of cancers. The frequencies of MSI were analyzed by testing the BAT-26 and BAT-25 markers. Results. MSI analysis revealed that 22.9% of the tumors (22 patients) were microsatellite instability positive and 77.1% (74 patients) were microsatellite instability negative. The highest rate of MSI (40.9%) was found in the rectal region. MSI-H status was seen more frequently in distal tumors (P = 0.04, odds ratio = 3.13, 0.96–10.14). Conclusions. Distal tumor location and MSI may associate with special clinicopathological features. It seems that there may be correlation with underlying genetic and immunologic mechanisms.
The search for host isolated probiotic bacteria from animal intestine may discover new probiotic candidates with promising health properties. This study evaluated the safety and functional probiotic potential of the lactic acid bacteria (LAB) isolated from the Iranian native ruminants intestine under in vitro assays. The isolates were selected according to criteria including survivability in low pH, bile salts, pancreatic enzymes, different temperatures, NaCl concentrations, antibacterial activities, presence of adhesion genes and safety characteristics. The selected LAB were then identified to species level using 16S rRNA gene sequencing. The results showed that out of one hundred and eighty-seven LAB isolates, only six strains (NABRII50, NABRII51, NABRII52, NABRII53, NABRII54 and NABRII55) were tolerant to low pH, bile salt, pancreatin enzyme, 45 C temperature and 2% sodium chloride. The six selected isolates belonged to Lactobacillus mucosae. Two of the adhesion genes (mub and map) were detected in all strains except NABRII53. The virulence factors were observed in NABRII50, NABRII53 and NABRII55. The tetracycline resistance gene (tet (S)) was detected in NABRII55. This study was the first effort to select Lb. mucosae strains with the probiotic potential from the Iranian ruminants intestine. These results revealed that the ruminant intestinal ecosystem could be considered as a valuable origin of probiotic candidates and all the selected LAB strains except NABRII50, NABRII53 and NABRII55 could be considered as promising probiotics.
HIGHLIGHTSLactobacillus mucosae strains isolated from Iranian native ruminants intestine including NABRII51, NABRII52 and NABRII54 showed probiotic potential under in vitro assays. The Lb. mucosae strains including NABRII51, NABRII52 and NABRII54 were able to survive in intestinal physiological conditions, and carried the adhesion genes, such as mub and map. In vitro biosafety assays confirmed that Lb. mucosae strains (NABRII51, NABRII52 and NABRII54) were safe to further studies.
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