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Objective: 22q11.2 chromosomal region is a hot spot for many cytogenetic rearrangements especially microdeletions which are responsible for DiGeorge and VeloCardioFacial syndromes. The most characteristic sign in these patients is congenital cardiac conotruncal anomalies. The gold standard diagnostic test for these microdeletions is FISH (Fluorescent In Situ Hybridization). However this diagnostic technique has some drawbacks such as high final cost and low sensitivity in smaller and uncommon microdeletions found in this region. The aim of this study was to introduce a less expensive and a priori more sensitive molecular method to help small and peripheral laboratories to find genetic causes of congenital heart diseases and DiGeorge syndrome. Materials and Methods: 10 patients with congenital conotruncal anomalies and symptoms of DiGeorge syndrome were included in this study. These patients had been analyzed by FISH probe TUPLE1 before the inclusion. 3 normal persons were included as normal controls for microdeletion region. Semi Quantitative Multiplex PCRs were designed based on known markers in and out of the region of intrest. Results were analyzed by TotalLab software. Results: 4 patients showed a decrease in gene dosage more than 60% compared to normal persons. FISH analysis found only one patient with microdeletion. Conclusion: The designed method based on semi quantitative PCR was able to find 4 patients (40%) with microdeletion in a population of 10 patients with congenital cardiac anomalies. This technique was also able to find microdeletions in three FISH negative patients. Molecular diagnosis of microdeletions is supposed to be more sensitive than FISH in small microdeletions. This study confirms the presence of atypical deletions in Iranian patients and shows that the applied technique can detect some FISH negative patients. However further studies are needed to determine the sensitivity and specificity of the mentioned molecular diagnosis. It seems that this can be used at least for the patients with typical phenotypic features of 22q11DS and negative FISH results.

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This paper aims at investigating the effect of heat input in resistance spot welding on microstructure and mechanical behavior of 2304 duplex stainless steel, as a promising candidate for automotive application. The results showed that due to rapid cooling rate inherent to resistance spot welding, the ferrite-austenite phase balance is destroyed and nitride-type precipitates are formed within the ferrite grains. The amount of austenite in the weld nugget was a function of welding current, as the most important factor affecting welding heat input. Increasing welding current increased the austenite volume fraction from 4 to 18%. Moreover, the nitride precipitation was reduced upon using higher welding currents. Investigation of weld mechanical performance during the tensile-shear loading showed that increasing welding current enhances both load bearing capacity and energy absorption capability. The maximum achievable peak load and energy absorption of 2304 duplex stainless steel resistance spot welds were 25 kN and 40 J indicating a superior weldability.

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In this work, joining of 4014 Aluminum tube to 7075 rod is studied using magnetic pulse welding process. The effect of impact angle (4, 6 and 8 degrees) and welding voltage (6 and 7 kV) on the joint are investigated. The microstructure of the weld cross section was evaluated using optical and scanning electron microscopy and mechanical properties of the welds were evaluated by microhardness and tensile tests. The results showed that, for the impact angles of 4 and 6º, the increase of welding voltage from 6 to 7 kV, leads to the change morphology of interfacial from straight to wavy. While, for the impact angle of 8º, the increase of the welding voltage increases local melting and results in the degradation of the interface. At the same angle, increasing the welding voltage increases the hardness due to the higher work hardening and severe plastic deformation. On the other hand, the effect of welding voltage on the hardness is dominant compared to the impact angle. The results of the tensile test showed that, for the low impact angles, increasing the welding voltage increases the shear strength, while, for the higher impact angles, it decreases the shear strength because of creating holes in welding interface. The results showed that joining of aluminum tube/rod with impact angle of 6º and welding voltage of 7 kV leads in uniform and wavy interface with higher shear strength in comparison with other conditions.