京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18160号 / 医博第3880号 / 新制||医||1003(附属図書館) / 31018 / 京都大学大学院医学研究科医学専攻 / (主査)教授 三森 経世, 教授 生田 宏一, 教授 宮地 良樹 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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OBJECTIVE: To determine the effects of vitamin C and insulin on osteoblasts harvested from neonatal mouse calvaria. To determine the effects of experimental media (vitamin C and insulin and a combination) on the ex-vivo live bone organ culture model and explore the capacity of addition of osteoblasts to allow for bone formation within a critical defect. To use the chick chorioallantoic membrane (CAM) model to explore bone formation within critical bone defect. METHODS: Osteoblasts were harvested from neonatal mice were tested using four types of experimental media: control DMEM, media prepared with 150 μg/ml vitamin C, 10 nM media, or a combination of both vitamin C, insulin, and a combination of vitamin C and insulin media. Cell were cultured for 18 days at 37°C. Neutral red was done to identify cellular activity and silver nitrate to detect calcium deposits. Two types of scaffolds were inserted into the defect: collagen membrane scaffold and NuOss (xenograft) with collagen scaffold. After 30 days the samples were collected for histological analysis. Neonatal mouse calvaria were harvested and a 2mm critical defect made on each calvaria. Each calvaria received a scaffold of collagen or NuOss with or without osteoblasts with one of three experimental media within the CAM model. After 7 days, the amnion membrane of the egg was dropped and a window was made. The calvaria with the scaffold samples were placed on the amnion membrane. The eggs were incubated for 10 days then the experiment was terminated. Calvaria were collected and processed for histological evaluation. RESULTS: Neutral red and silver nitrate of 2D in-vitro cells revealed calcium deposits in culture well using vitamin C media, cell cultured with insulin media showed calcium deposits and cell morphological change, and cell cultured with a combination of vitamin C and insulin media showed the most calcium deposits and morphological changed. Ex-Vivo samples with collagen scaffold had bone thickening but not enough nutrients for bone regeneration, despite the addition of cells. The collagen scaffold is a more suitable material than xenograft due to particle size. The CAM model showed new bone formation and new vessels were most abundant in areas closest to lining cells in collagen samples. Samples with additional osteoblasts added showed greater results. NuOss scaffold samples did not show the same bone formation or vessel growth. CONCLUSIONS: The results indicate and confirm the basic principles of tissue engineering. In order to have bone regeneration more cells allow for better results. The quality of the scaffold is important and should have stability as well as enough space for cellular migration and recruitment for new blood vessel to support regeneration of bone to its original state.

The remember-know paradigm is widely used in recognition memory research to explore the mechanisms underlying recognition judgments. The most intriguing question about the paradigm that needs to be answered is: Are the processes that underlie “remember” and “know” responses the same or different? The extant remember-know models provide different answers. The dual-process model (Yonelinas, 1994) assumes that “remember” and “know” judgments are made with qualitatively different underlying processes. The one-dimensional Signal Detection Theory (SDT) model (Donaldson, 1996; Hirshman & Master, 1997) and the Sum-difference Theory of Remembering and Knowing (STREAK) model assume that “remember” and “know” judgments are made with same underlying processes but different response criteria. In this thesis, three experiments were conducted to evaluate these models. The remember-know models were fit to the accuracy data to see which model provides the best account for the ROC data. In addition, the reaction time data were fit with ex-Gaussian distributions and the best-fit skew parameters were used to reveal whether the underlying strategic processes for “remember” and “know” judgments are same or not. The results of the remember-know model fit were mixed: In the first experiment with list length manipulation, 6 out of 8 cases were best fit with the one-dimensional models and the other 2 cases were best fit with the dual-process models; in the second experiment with list strength manipulation, 11 out of 18 cases were best fit with the one-dimensional models, another 6 cases were best fit with the dual-process models and the rest one case were best fit with the STREAK model; in the third experiment with response bias manipulation, 6 out of 16 cases were best fit with the one-dimensional models and the other 10 cases were best fit with the dual-process models. The results of ex-Gaussian fit to RT data supported the one-dimensional model better: for the subjects who provide enough overlapping data in comparison of the distributions of hits followed by “remember” and “know” judgments, the values of skew parameter did not differ for “remember” and “know” responses in 7 out of 8 cases. This indicates that the same process underlies “remember” and “know” responses.

This dissertation contributed three main areas to flexibility testing and biomechanical characterization of human spinal segments. The first was a literature review of existing testing methodology, the second examined common spine fixation procedures, and the third developed an improved fixation method. Spine biomechanical characterization is the primary technique for assessing the healthy, diseased, and surgically treated response of spinal tissues. However, despite decades of use, no standard testing protocol or reporting methodology for flexibility testing conditions has been established. As part of the present work, a comprehensive, systematic literature review was performed, and the methods sections of 242 relevant journal articles provided key information regarding preparation processes, fixation methods, testing temperatures, loading rates, loading magnitudes, and pre-conditioning procedures. The collated information was utilized to recommend best practices for testing and reporting flexibility testing methodology. Exothermic cementing processes were the dominant spinal fixation method from the reviewed articles. In these cases, fixation occurred when the most superior and inferior vertebrae of a functional spinal unit (FSU) were embedded into a cementing material that bound tightly to the cortical surface of the vertebrae, yielding a strong and geometrically favorable attachment point. The four most common fixation materials are highly exothermic and were tested to quantify the temperature rise in the adjacent intervertebral disc (IVD), as well as any associated thermal iatrogenic damage. Three thermocouples, inserted into three distinct locations of the IVD, measured temperatures throughout the cementing process. Polymethyl methacrylate (PMMA), the most frequently used cementing material, resulted in the greatest temperature increases, with a mean temperature rise up to 57°C above room temperature. Visible macro- and microscopic changes occurred in each of the cemented FSU IVDs. Changes included morphological changes, tissue desiccation, cracks, a breakdown in striations in the annulus fibrosus (AF), and denaturation and cell migration in the nucleus pulposus (NP). Based on these results, alternative vertebral attachment methods were considered and investigated. A structured design process was followed, and a mechanical ex vivo spinal fixation device which comprised a compliant vertebral clamp was designed. The geometry of the vertebral clamp was optimized based on pseudo-rigid body and finite element analyses. The final design was fabricated in titanium alloy (Ti6Al4V) using a 3D laser sintering process. Three clamps were manufactured and functionally validated. The opening/deployment and physiological loads of ± 7.5 N•m were cyclically tested on each clamp. The clamps showed no signs of failure and remained securely attached to the vertebrae. The resultant device/vertebrae interface stiffnesses were 4 to 10x greater than their corresponding FSU stiffnesses. The clamp design eliminated thermal iatrogenic damage, had minimal structural iatrogenic damage, was reusable, adjustable, and resulted in less than 10% of the previous preparation time.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13537号 / 論医博第2277号 / 新制||医||1065(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 篠原 隆司, 教授 近藤 玄, 教授 齋藤 潤 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Thesis(M.A. (Clinical Psychology)) -- University of Limpopo, 2018 / The study explored recidivism as a lived experience among the youth incarcerated at Polokwane Secure Care Centre in Polokwane, Limpopo Province. The study focused on describing the subjective meanings that recidivist youth attach to their behaviour and established what the youth consider to be the causes of their recidivist behaviour. Furthermore, the study explored what the youth perceive as possible interventions to reduce recidivism. A total of six participants (all males; aged between 16 and 18) were selected using the purposive sampling method. Data were collected using semi structured interviews. Thematic analysis method was used to analyse the data. The six major themes that emerged during data analysis were; a) labelling; b) peer pressure; c) substance abuse; d) socialisation; e) conduct disorder; and f) self discipline and constructive activities. The findings of the study suggest that various factors contribute to recidivism including the use of substances; parenting styles as well as peer pressure. Furthermore, the findings showed that behavioural problems including criminal behaviour in the youth, may be due to being labelled as a criminal or Conduct Disorder. The findings further suggest the influence the environment has on the youth, and how being socialised in an environment that emphasises a fancy lifestyle may contribute to the youth engaging in criminal activities to meet the standards of that particular environment. The findings further suggest that self discipline and of constructive activities may help to reduce recidivism among the youth. The study is concluded by, among others, recommending that psychological services be widely available to communities which will allow the youth to have easy access to such services. This may assist them in dealing with issues such as their experiences within the households (such as abuse) and how to better manage/ control their emotions as opposed to responding aggressively.

Chapter 1 examines the effect of property-type diversification in equity real estate investment trusts (REITs) from 1995 to 2006. A strong positive relationship is documented between property-type diversification and return on assets, return on equity, and Tobin’s Q. The diversification benefit comes from both the ability to select better performing property types in “hot” markets and the limited exposure to poorly performing property types in “cold” markets. Diversified REITs produce higher cash flows relative to equity as a result of a broader opportunity set; moreover, return on assets increases with the degree of diversification, which suggests significant shielding to property-type specific risk. Additionally, results indicate that diversified REITs operate and trade above their contemporaneous predicted values, which are calculated using imputed multipliers from specialized REITs. The evidence shows that the market is operating efficiently and has incorporated this information; diversified REITs Q ratios are significantly greater than specialized REITs. Chapter 2 uses a large sample of municipal bond closed-end funds to examine how tax liability affects seasonal trading. Optimal tax trading dictates that net tax liability be calculated after all trades. Investors’ net tax liability is held in a holding account of his or her choosing. This study investigates what happens when there is tax liability in excess of Safe Harbor, and tax holding accounts are liquidated to cover the payments. We find that there exists a pattern of negative returns and increased volume in the month of March that is unexplained by changes in yield. iii Chapter 3 examines the ex-dividend day effect for municipal bond closed-end. The proposed explanations for this phenomenon are tax effects, short-term trading and/or market microstructure effects. In this study I use a unique set of dividend distributions to provide additional evidence that ex-dividend behavior is related to taxation as well as short-term trading. The sample I use is comprised of dividends in nontaxable closed-end funds, which ordinarily are not subject to Federal Income Tax. However, there is an occasional distribution that is subject to capital gains or ordinary income tax. This provides a unique environment in which to study the ex-dividend price behavior of a fund while eliminating the need for comparisons across funds.