The role of NAG-1 in Tumorigenesis

This dissertation explores the nature of a divergent member of the Transforming Growth Factor-β [beta] superfamily, the non-steroidal anti-inflammatory drugs activated gene (NAG-1), as it relates to its regulation and biological activity in cancer context. Our lab has extensively studied on the molecular mechanism by which phytochemicals and NSAIDs induce apoptosis correlation with NAG-1 expression in human colorectal cancer (CRC) cells. Significant data from in vitro studies suggest that NAG-1 has an anti-tumorigenic activity which elicits apoptosis in a cyclooxygenase (COX)-independent manner in CRC cells. Indeed, NAG-1 transgenic mice developed less aberrant polyp foci (APC) compared to those of control counterpart in chemically- , genetically induced colorectal cancer models. However, it has been reported that NAG-1 has a tumor-promoting activity in a different cancer type such as prostate cancer and in chapter 1, a literature review for the regulation and the role of NAG-1 in the context of cancer will be discussed. Human pancreatic cancer cells treated with the PPARγ [gamma] ligand MCC-555 showed the feature of apoptosis with associated with NAG-1 induction. MCC-555 induces KLF4 expression via PPARγ-independent pathway, which in turn induces NAG-1 transactivation by which KLF4 binds to NAG-1 promoter region, suggesting NAG-1 is also implicated in apoptosis in human pancreatic cancer cells (Chapter 2). During the study on the signaling pathway and target genes affected by NAG-1, we observed nuclear expression of NAG-1. Nuclear NAG-1 moderates TGFβ signaling by interfering binding of Smad complex to DNA, leading to the inhibition of cell migration and invasion induced by TGFβ signaling (Chapter 3). Taken together, the studies presented in this dissertation suggest that NAG-1 maybe a driver factor for apoptosis not only in CRC cells, but in pancreatic cancer cells, and this effect might arise from the activity of nuclear NAG-1 which attenuates Smad signaling required for cancer survival and progression

New Frontiers of Laser Welding Technology

With the advances in power sources and optic technologies, high-power laser welding has been utilized in many applications such as automotive, battery manufacturing, and electronic industries. The low-heat input of laser power and its precise control enables minimal thermal damage and geometric inaccuracy in the weldment. Recently, laser welding has evolved in combination with machine learning, monitoring and control technology, new materials, and new processes. This Special Issue aims to present the recent advances in the development in innovative laser welding technologies based on new laser power sources, laser optics, systems, and monitoring technologies. A total of six papers are presented in this Special Issue

Role of Binder on Yield Strength of polycaprolactone/dimethylsulfone composites for bio-applications

Polycaprolactone (PCL) and dimethylsulfone (DMSO2) composites can tailor the properties of scaffold materials, allowing their use in bone tissue engineering. With an increase in DMSO2 content, the modulus of the material increases but not the yield strength. In order to increase yield strength, a binder was added. However, the optimization of the content and the mixing process of the binder were not optimized in the previous studies. In this study, gamma-methacryloxypropyltrimethoxysilane (A-174) was used as a binder to increase the strength of a composite. Four different mixing processes were employed based on the binder mixing sequence. The binders with content of 0, 0.4, 0.5, 0.7, and 1.5 phr were employed. The yield strengths of composites were investigated in terms of the binder mixing sequence and binder content. When the binder and DMSO2 particle fillers were premixed in the PCL matrix consisting of a DMSO2 filler and an A-174 binder system, the filler surface was coated smoothly and uniformly, and less agglomeration occurred. The yield strength of the composites with the appropriate mixing sequence was 36.71 % higher than that of the specimen without a binder, which was attributed to the improved adhesion between the matrix and fillers. Upon increasing the binder content, elongation and tearing of the matrix surface were observed in the cross-sections after yield tests; however, the weakening of mechanical anchoring was caused by excessive binder content, and filler debonding was observed on the surface. Because of the use of the A-174 silane binder at a concentration of 0.5 phr and the premixing of the binder and filler, the highest performance in terms of strength improvement of a PCL-20 wt % DMSO2 composite was achieved

Association between work-related health problems and job insecurity in permanent and temporary employees

OBJECTIVES: This research was conducted with an aim of determining the correlation between job insecurity and an employee’s work-related health problems among permanent and temporary workers. METHODS: Using the data from the First Korean Working Conditions Survey conducted in 2006, a total of 7,071 workers, excluding employers and the self-employed, were analyzed. Work-related health problems were categorized as backache, headache, abdominal pain, muscular pain, stress, fatigue, insomnia, anxiety or depression. Each problem was then analyzed for its relationship to job insecurity through logistic regression analysis. RESULTS: Among the 7,071 workers, 5,294 (74.9%) were permanent workers and 1,777 (25.1%) were temporary workers. For the permanent workers, presence of high or moderate job insecurity appeared more closely linked to backache, headache, abdominal pain, muscular pain, stress, fatigue, insomnia, anxiety, and depression compared to absence of job insecurity. However, for the temporary workers, only depression appeared to be associated with the presence of high job insecurity. CONCLUSION: The study showed that the presence of job insecurity is correlated with work-related health problems. The deleterious effects of job insecurity appeared to be stronger in permanent than temporary workers. Additional research should investigate ways to effectively reduce job insecurity