180 research outputs found
Does the Solow Residual for Korea Reflect Pure Technology Shocks?
This study investigates the relationship between the measured Solow residual and demand side variables for the Korean economy. The measured Solow residuals are shown to be Granger-caused by some demand side variables such as exports, M1, and government expenditure. A vector error correction model is constructed to investigate dynamic relation between these demand side variables and the Solow residual. Impulse response functions shows that the measured Solow residual moves pro-cyclically with the demand shocks, and that the forecast error variance of the measured Solow residual is mostly explained by past innovations of these demand side variablesSolow residual, Productivity shock, Vector error correction model
Risk features and relationship between financial variables and beta: An analysis of the casino industry
The purpose of this study was to investigate the relationship between the key financial variables of casino firms and their common stocks, and to examine the risk features and the diversifiability of casino stocks; The financial and stock return data for the period 1992-1994 in this study were obtained from the CD-ROM database of the University of Nevada, Las Vegas and the Center for Research in Security Prices (CRSP File) of the Graduate School of Business, University of Chicago. The relationship between four financial variables (current ratio, leverage ratio, asset turnover ratio, and profit margin ratio) and the casino beta was tested by using a cross-sectional multiple regression analysis; The study found that asset turnover ratio was negatively correlated with beta (i.e., a firm with high efficiency has a low beta), but current ratio, leverage ratio, and profit margin ratio were not significantly correlated with casino betas. The study also found that 92% of the total risk of casino firms between 1992 and 1994 was due to the unsystematic risk which is determined by firm-specific factors. Therefore, the volatility of casino stocks was primarily explained by each casino\u27s unique factors; The findings of the study suggest that the systematic risk of casino firms is related to the efficient management of casino assets. High efficiency leads to lower systematic risk and hence the value of casino firms may be enhanced
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Hotel Real Estate Investment Trusts (REITs): An Investication Of Market Performance Risk Features, And Risk Determinants
This empirical study investigates the long-term (1993-1999) performance of hotel REITs and compares it with five other REITs groups: office/industrial, residential, health care, retail, and diversified REITs. In addition, the study is designed to investigate the risk features of hotel REIT stocks as well as their determinants of systematic risk. Jenson\u27s abnormal performance index is adapted to investigate the performance of six property sectors of REITs relative to that of the market portfolio. A t-test is used to evaluate whether the difference in performance between the REIT sectors and the market portfolio is statistically significant. In addition, one-way ANOVA is employed to test the equality of the group means of risk-adjusted returns. To analyze the risk features of hotel REIT stocks, the overall risk of hotel REIT stocks, as measured by variance of monthly rate of return over 1993-1999, is decomposed into systematic risk and unsystematic risk. The cross-firm multiple regression statistical technique is employed for examining the effects of liquidity, financial leverage, profitability, operating efficiency, dividend payout, firm size, and growth on systematic risk for the hotel REITs industry
TLR7/8 Agonist Encapsulating Polymeric Nanoparticles for Cancer Immunotherapy
University of Minnesota Ph.D. dissertation. October 2018. Major: Pharmaceutics. Advisor: Jayanth Panyam. 1 computer file (PDF); xvi, 163 pages.The immune system is important for the prevention of cancer and formed the basis of cancer immunotherapy. That is, enhancement of the immune response for the treatment of malignant cancer cells. The field has undergone significant progress to include the use of checkpoint inhibitors, monoclonal antibodies and cytokine therapies. In addition, a cancer vaccine, composed of tumor associated antigens (TAAs) and vaccine adjuvant, is particularly promising. Effective vaccines can mobilize tumor-specific CD8 T cells to kill selectively tumor cells with cytotoxic granules and secrete IFN-ɣ that sensitize tumors to be susceptible to effector immune cells. Additionally, activated CD8 T cells become memory cells and can respond to same TAA-epitopes, which can be effective for long-term protective immunity to inhibit cancer recurrence. Activation of dendritic cells (DCs), which are the main antigen-presenting cells (APCs), is critical for T cell immunity. To an elicit tumor-specific CD8 T cell response, DCs have to process and present TAAs to CD8 T cells through the major histocompatibility complex (MHC) I. Moreover, co-stimulatory signals and pro-inflammatory cytokines are required to stimulate CD 8 T cells. However, CD8 T cell anergy and exhaustion will occur if TAA treatment is not sufficiently immunogenic to trigger DC activation. Therefore, development of immunostimulatory adjuvant that can trigger DC activation can enhance therapeutic efficacy of cancer vaccines. Imidazoquinoline-structured synthetic toll-like receptor (TLR) 7/8 agonists are strong cytokine inducers that can be a potent vaccine adjuvant. TLR7/8 ligation can activate MyD88 signaling pathways and stimulate DCs to upregulate co-stimulatory molecules and secrete pro-inflammatory cytokines and type I interferons. However, TLR7/8 agonists lack prominent efficacy in vivo due to the rapid clearance from the injection site. Following subcutaneous (SC) injection, small molecules enter the systemic circulation via blood capillaries and only small portion can reach the draining lymph nodes. Therefore, our goal was to develop a SC injectable drug carrier that can more efficiently deliver as well as prolong duration of at the site of action of TLR7/8 agonists. In this study, we fabricated poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) containing TLR7/8 agonists. Nanoparticulate delivery of TLR7/8 agonist showed enhanced DC activation and antigen-presentation compared to the soluble form of TLR7/8 agonists. When combined with peptide/tumor cell lysate-based antigens, NPs potentiated the antigen-specific CD8 T cell expansion and increased cytotoxic functions, which resulted in enhanced efficacy in both prophylactic and therapeutic tumor models. To further enhance endo/lysosomal delivery of TLR7/8 agonists in PLGA NPs, we included a sodium bicarbonate-mediated gas-generating system that is acidic pH-responsive. This approach resulted in 33-fold greater amount of TLR7/8 agonists encapsulated within the NPs. More importantly, the PLGA NP immunization elicited a stronger CD8 T cell response compared to conventional PLGA NPs, which in turn, enhanced therapeutic efficacy. As tumor microenvironment is immune suppressive, we examined whether modulation of tumor microenvironment can enhance the therapeutic efficacy of cancer vaccine. We reduced the immune suppressive cells including myeloid-derived suppressive cells (MDSCs) and regulatory T cells (Tregs) by daily oral dosing of a tyrosine kinase inhibitor (TKI), sunitinib. Additionally, we adapted an anti-PD-L1 antibody to block programmed death ligand 1 (PD-L1) expressed on tumor-associated (M2) macrophages and MDSCs that exhaust CD8 T cells, to augment the CD8 T cell activation at the tumor. In our study, combination of sunitinib and PD-L1 blockade significantly decreased the immune suppressive cell population and reduced PD-L1 expression on these cells. We also examined if nanoparticulate delivery of TLR7/8 agonist can potentiate NK cell-mediated cancer immunotherapy through its known effect on TH1 immunity. Antibody-dependent cellular cytotoxicity (ADCC) of monoclonal antibodies was found to be augmented in response to TLR7/8 agonist encapsulating NPs as a vaccine adjuvant. Overall, our studies demonstrate that PLGA NPs broaden the application of TLR7/8 agonists for improved cancer treatment. Moreover, this platform holds promise to enhance the efficacy of cancer vaccines composed of tumor associated antigens (TAAs) and vaccine adjuvan
The Effect of Imports and Exports on Total Factor Productivity in Korea
We investigate the effect of imports and exports on total factor productivity in Korea during 1980-2003. We find Granger causality from imports to total factor productivity (TFP) growth, but no causality from exports to TFP growth. We then investigate the impact of trade and other variables on TFP growth. According to our results, imports have a significant positive effect on TFP growth but exports do not. In addition, our results indicate that the positive impact of imports arises not only from the competitive pressures associated with the imports of consumer goods but also from technological transfers embodied in imports of capital goods from developed countries.
Azide-Alkyne Huisgen [3+2] Cycloaddition Using CuO Nanoparticles
Recent developments in the synthesis of CuO nanoparticles (NPs) and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC) nanoreactors and ZnO-CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.open6
Cytosolic Internalization of Anti-DNA Antibodies by Human Monocytes Induces Production of Pro-inflammatory Cytokines Independently of the Tripartite Motif-Containing 21 (TRIM21)-Mediated Pathway
Anti-DNA autoantibodies are a hallmark of systemic lupus erythematosus (SLE). A subset of anti-DNA IgG autoantibodies is cell-internalizable; thus they can enter living cells in the form of free IgG. However, the contribution made by the Fc region of internalized free-form IgG to the cytokine response has not been studied, despite the recent discovery of tripartite motif-containing 21 (TRIM21), a cytosolic Fc receptor involved in immune signaling. This study used an internalizable IgG anti-DNA antibody (3D8) to examine the cytokine responses of human monocytes to the Fc region of cytosolic free IgG. Internalization of 3D8 IgG and a 3D8 single-chain variable fragment-Fc (scFv-Fc) induced production of IL-8 and TNF-α via activation of NF-κB. By contrast, a 3D8 scFv (comprising variable domains alone) did not. This suggests Fc-dependent cytokine signaling. A 3D8 IgG-N434D mutant that is not recognized by TRIM21 induced greater production of cytokines than 3D8 IgG. Moreover the amounts of cytokines induced by 3D8 IgG in TRIM21-knockdown THP-1 cells were higher than those in control cells, indicating that cytokine signaling is not mediated by TRIM21. The results suggest the existence of a novel Fc-dependent signaling pathway that is activated upon internalization of IgG antibodies by human monocytes
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