Abstract In the article, a new approach considering structural local failure for topology optimization of continuum structure is proposed. It aims at not only lowering the risk of local failure in the concerned structural regions, but also ensuring a good stiffness of the structure. The local failure may be caused by the structural uncertainties or possible structural fatigue. To this end, a criterion to evaluate the effect of one local failure on the structure is introduced. This criterion is minimized to reduce the probability of structural damage based on an initialized structure whose compliance is optimized. Solid Isotropic with Material Penalization (SIMP) method and Optimality Criteria (OC) method are combined to solve the design problem. The effectiveness of the proposed algorithm is verified by a series of numerical examples. Furthermore, experiments merging with additive manufacturing technique are taken to prove the practical ability of the method in actual engineering.

RESUMO CONTEXTO E OBJETIVO: Enzimas dimetilarginina dimetilaminohidrolase (DDAH), codificadas por genes DDAH1 e DDAH2, desempenham papel fundamental na manutenção da função endotelial. Realizamos estudo tipo caso-controle na população chinesa, com três grupos étnicos (han, kazakh e uygur) para investigar sistematicamente a associação entre a variação de genes DDAH1 e DDAH2 e a hipertensão. DESENHO E LOCAL: Estudo tipo caso-controle no Departamento de Medicina Interna e Diagnóstico Genético, Hospital de Tongji, Tongji Medical College, Universidade de Ciência e Tecnologia de Huazhong. MÉTODOS: Este estudo incluiu 1.224 pacientes com hipertensão e 967 indivíduos saudáveis, sem parentesco, como controles. DDAH1 -396 4 N (GCGT) del > ins, rs3087894, rs805304 and rs9267551 foram genotipados usando o ensaio nuclease TaqMan 5'. RESULTADOS: O genótipo G/C de rs3087894 no DDAH1 foi um fator de risco para a hipertensão arterial no grupo kazakh em modelo codominante (G/C versus G/G; OR 1,39; IC 95%: 1,02-1,88; P < 0,05), com o mesmo resultado no modelo dominante (G/C + C/C versus G/G; OR 1,38; IC 95%: 1,03-1,84; P < 0,05). Em contraste, o genótipo C/C de rs3087894 parecia ser um fator de proteção para a hipertensão no grupo uygur no modelo recessivo (C/C versus G/G + G/C; OR 0,62; IC 95%: 0,39-0,97; P < 0,05). Achado semelhante para rs3087894 também foi observado depois de se ajustar a variante à covariante idade. CONCLUSÃO: Os nossos resultados indicaram que o C-alelo de rs3087894 no DDAH1 foi fator de risco para a hipertensão no grupo de kazakh, mas fator de proteção no grupo de uygur.

CONTEXT AND OBJECTIVE: Dimethylarginine dimethylaminohydrolase enzymes (DDAH), which are encoded by the genes DDAH1 and DDAH2, play a fundamental role in maintaining endothelial function. We conducted a case-control study on a Chinese population that included three ethnic groups (Han, Kazakh and Uygur), to systemically investigate associations between variations in the genes DDAH1 and DDAH2 and hypertension. DESIGN AND SETTING: Experimental study at the Department of Internal Medicine and Genetic Diagnosis, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. METHODS: This case-control study included 1,224 patients with hypertension and 967 healthy unrelated individuals as controls. DDAH1 -396 4N (GCGT) del>ins, rs3087894, rs805304 and rs9267551 were genotyped using the TaqMan 5' nuclease assay. RESULTS: The G/C genotype of rs3087894 in DDAH1 was a risk factor for hypertension in the Kazakh group in the co-dominant model (G/C versus G/G) (OR 1.39; 95% CI: 1.02-1.88; P < 0.05), with the same result in the dominant model (G/C + C/C versus G/G) (OR 1.38; 95% CI: 1.03-1.84; P < 0.05). In contrast, the C/C genotype of rs3087894 seemed to be a protective factor against hypertension in the Uygur group in the recessive model (C/C versus G/G + G/C) (OR 0.62; 95% CI: 0.39- 0.97; P < 0.05). Similar findings for rs3087894 were also observed after adjusting the variable for the age covariate. CONCLUSION: Our results indicated that the C-allele of rs3087894 in DDAH1 was a risk factor for hypertension in the Kazakh group but a protective factor in the Uygur group.