Essays on Health Insurance Market Design and Labor Market Interactions

This dissertation aims to develop empirical frameworks to assess a variety of health insurance market policies and explore the optimal policy design taking into account their impacts on the labor market and public insurance program. The first chapter (co-authored with Hanming Fang) presents and empirically implements an equilibrium labor market search model where risk averse workers facing medical expenditure shocks are matched with firms making health insurance coverage decisions. We use our estimated model to evaluate the equilibrium impact of the 2010 Affordable Care Act (ACA) and find that it would reduce the uninsured rate among the workers in our estimation sample from 20.12% to 7.27%. The second chapter evaluates the current health insurance exchange (HIX) system implemented under the ACA and examines its optimal design, accounting for adverse selection and equilibrium labor market interactions. I develop and empirically implement a life cycle equilibrium labor market search model integrated with the pre-ACA health insurance market. Counterfactual experiments show that the ACA decreases not only the uninsured rate but also aggregate labor productivity. Next, I examine the optimal design of HIX by choosing the values of three major design components---tax penalties on the uninsured, premium subsidies and age-based rating regulations. I find that the optimal combination of these components makes it less beneficial for older workers relative to younger workers to purchase health insurance from HIX. Implementing the optimal structure leads to higher labor productivity and a slightly lower uninsured rate. The third chapter (co-authored with You Suk Kim) studies the incentives for private insurers to use advertising to attract low-cost, healthy individuals and the impacts of advertising on selection, competition, and welfare in the context of the Medicare Advantage (MA). We develop and estimate an equilibrium model of the MA market, which incorporates strategic advertising by insurers. We find that advertising has positive effects on overall demand, but a much larger effect on the demand of the healthy individuals. Moreover, we find that advertising accounts for 15% of the selection of healthier individuals into MA. The impact of risk adjustment policies is also examined

Building Movie Map -- A Tool for Exploring Areas in a City -- and its Evaluation

We propose a new Movie Map system, with an interface for exploring cities. The system consists of four stages; acquisition, analysis, management, and interaction. In the acquisition stage, omnidirectional videos are taken along streets in target areas. Frames of the video are localized on the map, intersections are detected, and videos are segmented. Turning views at intersections are subsequently generated. By connecting the video segments following the specified movement in an area, we can view the streets better. The interface allows for easy exploration of a target area, and it can show virtual billboards of stores in the view. We conducted user studies to compare our system to the GSV in a scenario where users could freely move and explore to find a landmark. The experiment showed that our system had a better user experience than GSV

Differentiation of Smooth Muscle Cells from Human Amniotic Mesenchymal Cells Implanted in the Freeze-Injured Mouse Urinary Bladder

Background: The multipotency of human amniotic mesenchymal cells (HAMCs) has been reported, but the role of HAMCs in urinary tract regeneration is unknown. Objective: The aim of the study was to determine if cells derived from HAMCs support the structural and functional reconstruction of freeze-injured mouse bladders. Design, setting, and participants: HAMCs were harvested from an amnion membrane, and cells were cultured for 7 d prior to injection into the freeze-injured bladder walls of nude mice. Intervention: Three days prior to implantation, the posterior bladder walls were freeze injured for 30 s. The cultured HAMC-derived cells (0.5 x 10(5) cells per 50 mu l) were implanted into the injured regions. Control bladders received a cell-free injection. At 1, 2, 4, and 6 wk after the cell implantation, the experimental bladders were extirpated. Measurements: The bladder tissues were examined by immunohistochemistry for alpha-smooth muscle actin (SMA). The HAMC-derived cells were detected by antihuman nuclei antibody (HuNu). Separately, bladder muscle strips were examined for contractile responses to potassium. Results and limitations: At 1 wk after implantation, the HAMC-derived cells, which were detected by HuNu, differentiated into muscular layers composed of SMA-positive cells. From 2 to 6 wk after implantation, abundant layers of SMA-positive and HuNu-positive cells developed. In control bladders, few SMA-positive cells remained at the injured regions at 1 wk, but by 6 wk, more were present. At 1 wk, the contractile responses to potassium of the cell-implanted bladders were significantly higher than those of the control-injected ones. Control-injected bladders also recovered by 6 wk, but the rate of recovery was slower. Conclusions: Freeze-injured mouse bladders implanted with HAMC-derived cells recovered morphology and function faster than control-injected bladders.ArticleEUROPEAN UROLOGY. 58(2):299-306 (2010)journal articl

Evaluation of internal margins for prostate for step and shoot intensity‐modulated radiation therapy and volumetric modulated arc therapy using different margin formulas

[Purpose] This feasibility study evaluated the intra-fractional prostate motion using an ultrasound image-guided system during step and shoot intensity-modulated radiation therapy (SS-IMRT) and volumetric modulated arc therapy (VMAT). Moreover, the internal margins (IMs) using different margin formulas were calculated. [Methods] Fourteen consecutive patients with prostate cancer who underwent SS-IMRT (n = 5) or VMAT (n = 9) between March 2019 and April 2020 were considered. The intra-fractional prostate motion was observed in the superior–inferior (SI), anterior–posterior (AP), and left–right (LR) directions. The displacement of the prostate was defined as the displacement from the initial position at the scanning start time, which was evaluated using the mean ± standard deviation (SD). IMs were calculated using the van Herk and restricted maximum likelihood (REML) formulas for SS-IMRT and VMAT. [Results] For SS-IMRT, the maximum displacements of the prostate motion were 0.17 ± 0.18, 0.56 ± 0.86, and 0.18 ± 0.59 mm in the SI, AP, and LR directions, respectively. For VMAT, the maximum displacements of the prostate motion were 0.19 ± 0.64, 0.22 ± 0.35, and 0.14 ± 0.37 mm in the SI, AP, and LR directions, respectively. The IMs obtained for SS-IMRT and VMAT were within 2.3 mm and 1.2 mm using the van Herk formula and within 1.2 mm and 0.8 mm using the REML formula. [Conclusions] This feasibility study confirmed that intra-fractional prostate motion was observed with SS-IMRT and VMAT using different margin formulas. The IMs should be determined according to each irradiation technique using the REML margin

Gosha-jinki-gan Reduces Transmitter Proteins and Sensory Receptors Associated with C Fiber Activation Induced by Acetic Acid in Rat Urinary Bladder

This is a preprint of an article published in [NEUROUROLOGY AND URODYNAMICS. 27(8):832-837 (2008)].ArticleNEUROUROLOGY AND URODYNAMICS. 27(8):832-837 (2008)journal articl

Photochemical characterization of actinorhodopsin and its functional existence in the natural host

Actinorhodopsin (ActR) is a light-driven outward H+ pump. Although the genes of ActRs are widely spread among freshwater bacterioplankton, there are no prior data on their functional expression in native cell membranes. Here, we demonstrate ActR phototrophy in the native actinobacterium. Genome analysis showed that Candidatus Rhodoluna planktonica, a freshwater actinobacterium, encodes one microbial rhodopsin (RpActR) belonging to the ActR family. Reflecting the functional expression of RpActR, illumination induced the acidification of the actinobacterial cell suspension and then elevated the ATP content inside the cells. The photochemistry of RpActR was also examined using heterologously expressed RpActR in Escherichia coli membranes. The purified RpActR showed lambda(max) at 534 nm and underwent a photocycle characterized by the very fast formation of M intermediate. The subsequent intermediate, named P-620, could be assigned to the 0 intermediate in other H+ pumps. In contrast to conventional 0, the accumulation of P620 remains prominent, even at high pH. Flash-induced absorbance changes suggested that there exists only one kind of photocycle at any pH. However, above pH 7, RpActR shows heterogeneity in the H+ transfer sequences: one first captures H+ and then releases it during the formation and decay of P-650, while the other first releases H+ prior to H+ uptake during P-620 formation. (C) 2016 Elsevier B.V. All rights reserved