Abstract This paper describes the development and application of a frictionless contact stress solver based on the cell-centred finite volume method. The contact methodology, implemented in the open-source software OpenFOAM, is derived from the penalty method commonly used in finite element contact algorithms. The solver is verified on two benchmark tests using the available Hertzian analytical solutions.

Abstract In many countries, tax incentives are a popular means to achieve political, economic and social objectives. Their aim is to reach and accelerate certain activities of public interest. Furthermore, one of the objectives is to accelerate the development of a certain industry and influence the growth of research and investment in foreign capital. Innovation is the key element that helps a company achieve competitive advantage. Global competition is forced to offer unique products with added values on the market. Tax incentives for research and development are an important factor of innovation. This paper aims to present the importance of research and development, as well as the role of tax incentives. States should use their fiscal policy to stimulate investment in research and development through various forms of tax relief. The Republic of Croatia applies tax incentives for research and development, but to a significantly less extent than other European Union countries.

Differentiated thyroid cancers include papillary and follicular carcinomas, both originating from follicular epithelium. Treatment of choice is usually total or near total thyroidectomy, followed by ablative radioiodine 131I treatment, and by the long-term administration of thyroid hormone. Despite its excellent prognosis, recurrent disease does occur in approximately 20-40% of patients. Guidelines for the follow-up management of differentiated thyroid cancer are commonly based on circulating thyrogobulin measurement in the complete absence of eutopic thyroid tissue. A retrospective review was conducted on 116 patients (66 papillary and 50 follicular carcinoma, mean age 51.2 years) who had undergone total or near total thyroidectomy and radioactive iodine remnant ablation. Serum thyroglobulin (Tg) and anti-thyroglobulin antibodies (TgAb) levels were measured preoperatively, 1 month after thyroidectomy (before 131I treatment) and 6 and 12 months after ablation therapy (Tg1, TgAb1 and Tg2, TgAb2, respectively). During one year of follow-up, in a total of 24 patients (21%) recurrent disease were confirmed by ultrasonography and whole-body-scanning, mostly. It was found significant correlation between serum Tg levels (measured preoperatively and postoperatively) and recurrent diseases (p < 0.05), while serum TgAb levels did not have any statistical significance. However, in multivariate regression analysis only Tg levels measured 12 months after the therapy (Tg2) remained a significant predictor of recurrent disease (p = 0.008). Although a high Tg level before surgery does not indicate that tumor is present, in the postoperative period and after ablative therapy Tg has proven predictive value because stimulated Tg levels above 10 ng/ml confirmed that indicate residual or recurrent cancer, and its periodically measurements is recommended.