Схема образования стружки при несвободном резании

Дан анализ существующих схем образования стружки при свободном и несвободном резании материалов. Предложен новый подход к описанию зоны стружкообразования при несвободном резании с единственной условной поверхностью сдвига. Решена задача аналитического описания формы условной поверхности сдвига в общем виде. Приведены примеры анализа зоны стружкообразования для острозаточенного и закругленного лезвия инструмента. Показана актуальность полученных результатов для решения задач механики процесса резания материалов лезвийными инструментами. The analysis of existing schemes chip formation with the free and non-free cutting materials. A new approach to the description of chip area with an unfree cutting with a single conventional shear surface. The problem of analytical description of the conditional form shear surfaces in general. Examples of chip area for analysis ostrozatochennogo and rounded blade tool. The urgency of the results for the solution of problems of the process of cutting edge tools of mechanics of materials

Prevalence of Wt1 Mutations in A Large Cohort of Patients with Steroid-Resistant and Steroid-Sensitive Nephrotic Syndrome

Background. Nephrotic syndrome (NS) represents the association of proteinuria, hypoalbuminemia, edema, and hyperlipidemia. Steroid-resistant nephrotic syndrome (SRNS) is defined by primary resistance to standard steroid therapy. It remains one of the most intractable causes for end-stage renal disease (ESRD) in the first two decades of life. Sporadic mutations in the Wilms' tumor suppressor gene WT1 have been found to be present in patients with SRNS in association with Wilms' tumor (WT) and urinary or genital malformations, as well as in patients with isolated SRNS. Methods. To further evaluate the incidence of WT1 mutations in patients with NS we performed mutational analysis in 115 sporadic cases of SRNS and in 110 sporadic cases of steroid-sensitive nephrotic syndrome (SSNS) as a control group. Sixty out of 115 (52%) patients with sporadic SRNS were male, 55/115 (48%) were female. Sex genotype was verified by haplotype analysis. Mutational analysis was performed by direct sequencing and by denaturing high-performance liquid chromatography (DHPLC). Results. Mutations in WT1 were found in 3/60 (5%) male (sex genotype) cases and 5/55 (9%) female (sex genotype) cases of sporadic SRNS, and 0/110 (0%) sporadic cases of SSNS. One out of five female patients with mutations in WT1 developed a WT, 2/3 male patients presented with the association of urinary and genital malformations, 1/3 male patients presented with sexual reversal (female phenotype) and bilateral gonadoblastoma, and 4/5 female patients presented with isolated SRNS. Conclusion. According to the data acquired in this study, patients presenting with a female phenotype and SRNS and male patients presenting with genital abnormalities should especially be screened to take advantage of the important genetic information on potential Wilms' tumor risk and differential therapy. This will also help to provide more data on the phenotype/genotype correlation in this patient population.Wo