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The objectives of this dissertation include describing and analyzing the patterns of inequality in ALE participation at both the micro and macro levels. Special attention is paid to social origins of individual adults and their association with two groups of macro-level factors, social inequality (income, education, and skill inequality) and institutional settings (SEP, ALMPs, stratification, and TUD), across twelve selective OECD countries. In addition, this dissertation develops a deeper understanding of policy dimensions of inequality in ALE participation. A focus is placed on the historical development of ALE policies and the policy environment in Korea, Finland, and the U.S. that may serve as a component of the political, social and economic factors affecting ALE participation. To achieve these objectives, both quantitative (binary logistic regression and multilevel analysis) and qualitative methods (multiple case study) are employed.This investigation finds that the advantage of social origins in ALE participation is present across countries, to varying degrees. The advantage of social origins in NFALE and JRNFALE participation is associated with income and education inequality. It is associated with education inequality in FALE participation. For institutional settings, public spending on ALMPs and TUD are negatively associated with the advantage of social origins in NFALE and JRNFALE participation only. The multiple case study indicates that convergence in ALE policy and policy environment is identified in the three countries: predominance of market-driven ALE and job-related ALE, the decentralization of the ALE system, and decreasing public support. Lastly, an effort was made to relate the findings from the quantitative analyses to the analysis of the historical development of the ALE policy environment to provide reasonable background to explain inequality in ALE participation along with the three elements of neoliberal ideology, HRD-driven ALE policy, individual responsibility and the withdrawal of the State. In a market-driven policy environment where individual adults should take responsibility for their education and training with decreasing public support for education, adults with low social origins are less likely to participate in ALE. Ultimately, as ALE is a multi-dimensional issue concerning its roles and objectives, a comprehensive approach is required to address inequality in ALE participation.

This study is focused on synthesizing Nitinol by additive manufacturing that can provide desirable mechanical properties for orthopedic implants and adding functionally gradient coating that can enhance both safety and biocompatibility for orthopedic implant applications. The characteristics of additively manufactured Nitinol, by using the direct energy deposition (DED) technique, were experimentally studied. Because of a unique layer-by-layer manufacturing scheme, the microstructure and associated properties (mechanical and thermo-mechanical properties) of the DED Nitinol is different compared to conventionally produced Nitinol. Both the feasibility of manufacturing defect-free microstructure and the precise control of chemical composition were demonstrated. Effects of chemical compositions and post heat-treatment conditions on the phase transformation temperatures of the DED Nitinol were systematically analyzed and compared with those of conventional Nitinol. More precise control of phase transformation temperature from DED Nitinol was possible due to incoherent precipitate formation during aging heat treatment. In a similar way, the mechanical properties of the DED Nitinol were less sensitive to its chemical compositions and post heat-treatment conditions. The feasibility of the precise control of both mechanical and thermo-mechanical properties of the DED Nitinol was demonstrated which can broaden its applications. The bulk polycrystalline properties of the NiTi phase were studied via molecular dynamics (MD) simulations. Thermo-mechanical properties that are highly sensitive to chemical composition were not precisely predicted from previous reports and studies. In this study, realistic boundary conditions were applied to calculate bulk polycrystalline properties. Thermally driven phase transitions of NiTi between martensite and austenite are simulated with external stresses in both normal and shear directions. It is shown that phase transformation temperatures are affected by applied external stresses, and realistic values compared to experimental data are correctly predicted only when external stresses in both normal and shear directions are similar to the experimentally observed values of 0.05 – 0.1 GPa. The experimentally observed grain orientation and grain boundary thickness were applied to simulation domains for the prediction of the elastic moduli. The elastic moduli of polycrystalline NiTi structure was calculated as 52 GPa which is close to the experimentally reported value of 20-40 GPa while other studies predicted over 85 GPa. Lastly, pure titanium gradient layers were coated on the Nitinol surface for orthopedic implant applications to eliminate potentially toxic Ni ion release. Using the DED technique, both the core Nitinol and titanium gradient layers were manufactured with high purity and without microstructural defects. An additional biomedical coating of Hydroxyapatite (HA) was deposited on the outer surface using the cold spray technique. The resultant bonding strength was determined to be 26 MPa which exceeded the requirement of the ISO-13779 standard (15 MPa). The in vitro test of the Ni release rate from the entire gradient Nitinol structure was very low, which was comparable to drinking water.

Background Errors in counting spinal segments are common during interventional procedures when there are transitional vertebrae. In this study, we investigated the prevalence of the transitional vertebrae including thoracolumbar transitional vertebra (TLTV) and lumbosacral transitional vertebrae (LSTV). The relationship between the existence of TLTV and abnormal rib count or the existence of LSTV were also evaluated. Methods The vertebral levels were counted craniocaudally, starting from C1, based on the assumption of 7 cervical, 12 thoracic, and 5 lumbar vertebrae, using whole spine spiral three-dimensional computed tomographic images. The 20th and 25th vertebrae were defined as L1 and S1, respectively. Results In total, 150 patients had TLTV, with a prevalence of 11.2% (150/1,340). LSTV was observed in 111 of 1,340 cases (8.3%). Sacralization was observed in 68 of 1,340 cases (5.1%) and lumbarization in 43 of 1,340 cases (3.2%). There was a significant relationship between the existence of TLTV and the abnormal rib count (odds ratio [OR]: 117.26, 95% confidence interval [95% CI]: 60.77–226.27; P < 0.001) and LSTV (OR: 7.38, 95% CI: 3.99–13.63; P < 0.001). Conclusions Our study results suggest that patients with TLTV are more likely to have an abnormal rib count or LSTV. If a TLTV or LSTV is seen on the fluoroscopic image, a whole spine image is necessary to permit accurate numbering of the lumbar vertebra.