Part 2. Korea and the Major Powers : The Future of U.S.-China Relations and The Korean Peninsula

( Avery Goldstein ) 경남대학교 극동문제연구소 2002 The Korean Peninsula in Transition : The Summit an Vol.- No.-

Pseudo plastic zone analysis of steel frame structures comprising non-compact sections

Avery, P.,Mahendran, M. Techno-Press 2000 Structural Engineering and Mechanics, An Int'l Jou Vol.10 No.4

Application of "advanced analysis" methods suitable for non-linear analysis and design of steel frame structures permits direct and accurate determination of ultimate system strengths, without resort to simplified elastic methods of analysis and semi-empirical specification equations. However, the application of advanced analysis methods has previously been restricted to steel frames comprising only compact sections that are not influenced by the effects of local buckling. A concentrated plasticity method suitable for practical advanced analysis of steel frame structures comprising non-compact sections is presented in this paper. The pseudo plastic zone method implicitly accounts for the effects of gradual cross-sectional yielding, longitudinal spread of plasticity, initial geometric imperfections, residual stresses, and local buckling. The accuracy and precision of the method for the analysis of steel frames comprising non-compact sections is established by comparison with a comprehensive range of analytical benchmark frame solutions. The pseudo plastic zone method is shown to be more accurate and precise than the conventional individual member design methods based on elastic analysis and specification equations.

Biodegradable dexamethasone polymer capsule for long-term release

Avery Zheng,Thomas Waterkotte,Tilahun Debele,Gregory Dion,박윤지 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.2

We have developed sustained Dex (dexamethasone) capsule implants for sustained local delivery for inflammatory disease treatment. Four different biodegradable polymers were used as capsule materials: polycaprolactone (PCL), poly(lactic acid) (PLA), 90:10 poly(lactic-co-glycolide) (PLGA), and 50:50 PLGA. The drug release profiles from the four types of capsule were compared and the profiles were fit to a cylindrical reservoir first-order kinetics model. As a result, 50:50 PLGA showed the fastest release with the largest permeability and partition coefficient at 0.4909 nm/s and 1.9519, respectively. On the other hand, PCL showed the slowest release with the smallest permeability and partition coefficient at 0.1915 nm/s and 0.8872, respectively. The results indicate that the drug release kinetics are highly correlated with hydrophobicity of the polymer sheet: the more hydrophobic, the slower the drug release kinetics for the hydrophilic drug. The in vitro therapeutic efficacy of the Dex implant was also explored using TNF-α stimulated human umbilical vein endothelial cells (HUVECs), showing effective suppression of IL-6 levels with the implant compared to free Dex with minimal toxicity. Overall, this study suggests that the release trend of Dex from implants follows the hydrophobicity of each polymer, and the Dex implant inhibits the IL-6 expression effectively.

Surface Modifications of Titanium Dental Implants with Strontium Eucommia Ulmoides to Enhance Osseointegration and Suppress Inflammation

Avery Rui Sun,Qili Sun,Yansong Wang,Liqiu Hu,Yutong Wu,Fenbo Ma,Jiayi Liu,Xiangchao Pang,Bin Tang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Titanium (Ti) is now widely used as implant material due to its excellent mechanical properties and superior biocompatibilities, while its inert bioactivities might lead to insufficient osseointegration, and limit its performance in dental applications. Methods We introduced a robust and simple approach of modifying titanium surfaces with polysaccharide complexes. Titanium samples were subjected to hydrothermal treatment to create a uniform porous structure on the surface, followed by coating with a bioinspired and self-assembly polydopamine layer. Strontium Eucommia Ulmoides Polysaccharide (EUP-Sr) complexes are then introduced to the polydopamine-coated porous titanium. Multiple morphological and physiochemical characterizations are employed for material evaluation, while cell proliferation and gene expression tests using macrophages, primary alveolar bone osteoblasts, and vascular endothelial cells are used to provide an overall insight into the functions of the product. The significances of statistical differences were analyzed using student’s t-test. Results Microscopic and spectrometric characterizations confirmed that the Ti surface formed a porous structure with an adequate amount of EUP-Sr loading. The attachment was attributed to hydrogen bonding between the ubiquitous glycosidic linkage of the polysaccharide complex and the ring structure of polydopamine, yet the loaded EUP-Sr complex can be gradually released, consequently benefiting the neighboring microenvironment. Cell experiments showed no cytotoxicity of the material, and the product showed promising anti-inflammation, osseointegration, and angiogenesis properties, which were further confirmed by in vivo evaluations. Conclusion We believe the EUP-Sr modified titanium implant is a promising candidate to be used in dental applications with notable osteoimmunomodulation and angiogenesis functions. And the novel technique proposed in this study would benefit the modification of metal/inorganic surfaces with polysaccharides for future research.

When Fighting Ends

Avery Goldstein,Edward D. Mansfield 동아시아재단 2011 Global Asia Vol.6 No.2

THE FUTURE OF U.S.-CHINA RELATIONS AND THE KOREAN PENINSULA

Goldstein, Avery 경남대학교 극동문제연구소 2002 ASIAN PERSPECTIVE Vol.26 No.3

Korea remains one of the principal issues on the Asian agenda in which both the United Stated and China have a strong interest. This article explores some of the links between changing Sino-American relations and the future of Korea. It does so in three steps. First, it examines the international context within which China and the United States currently operate. Second, it examines key interests shaping their bilateral relations relevant to the future of the Korean peninsula, especially China's security concerns as a rising power in an era of American preponderance. Beijing's interest in increasing its international influence while also maintaining valuable economic ties to the United States (both essential to ensuring the Chinese Communist Party's political legitimacy at home) presents China's leaders with conflicting foreign policy imperatives manifest in their view of events in Korea. And third, the article examines four highly stylized scenarios depicting Korean futures and their significance for Sino-American relations.

Total Syntheses of Epothilones B and D

Mitchell A. Avery,Yan-Song Zheng,Kimberly K. Vines,Rajashaker Kache,Jae-Chul Jung 大韓藥學會 2004 大韓藥學會 總會 및 學術大會 Vol.2004 No.2

A pharmacokinetic comparison of homodimer ARB-92 and heterodimer ARB-89: novel, potent antimalarial candidates derived from 7β-hydroxyartemisinin

Bonnie A. Avery,Deepthi Pabbisetty,Lie Li,Abhisheak Sharma,Mahesh K. Gundluru,Amar G. Chittiboyina,John S. Williamson,Mitchell A. Avery 한국약제학회 2018 Journal of Pharmaceutical Investigation Vol.48 No.5

The ultimate goal of this study was to identify an orally active, affordable, potent and safe antimalarial drug based on the natural product artemisinin. During these efforts, a series of novel 7β-hydroxyartemisinin analogs were synthesized and characterized in vitro for their antimalarial activity against Plasmodium falciparum. Heterodimerization of 7β-hydroxyartemisinin provided the asymmetrical carbamate (ARB-89) while homodimerization provided the carbonate (ARB-92). These dimers were found to be highly active in vitro with an IC50 ≤ 0.50 nM against P. falciparum infected human red blood cells (RBC). For further development as potential antimalarial agents, a battery of in vitro and in vivo pharmacokinetic experiments was performed to distinguish the fate of the discovery compounds ARB-89 and ARB-92. Two UPLC-MS methods were developed and validated for the analysis of the compounds. Both ARB- 89 and ARB-92 exhibited moderate affinity (51 and 56%, respectively) to parasitized RBC, which is a perquisite for antimalarial activity. Following a single dose oral and intravenous pharmacokinetic study in rats, ARB-89 displayed a high clearance (92.8 ± 5.6 L/h kg), short elimination half-life ( t1/2, 1.2 ± 0.2 h) and moderate oral bioavailability (23.4%). ARB-89 was found to be excreted unchanged in feces, which may be due to its high lipophilicity, molecular weight and low oral exposure. In an attempt to identify a better lead antimalarial compound, ARB-92 was designed to be more water soluble than ARB-89 by incorporating a protonatable tertiary amine as part of the dimerizing ligand for 7β-hydroxyartemisinin. As anticipated, ARB-92 displayed a lower clearance (2.9 ± 0.7 L/h kg) and subsequently a longer t1/ 2 (2.3 ± 0.2 h) compared to ARB-89. The oral bioavailability of ARB-92 was found to be 34% in rats, a value somewhat better than the marketed artemisinin derivatives artenimol (19.3%), artemether (19.7%) or artesunate (29.5%).

The Importance of Reaction Mechanisms in Interpreting the Arsenic Reactive Transport of FeS-coated Sand Column

한영수,Avery H. Demond,Kim F. Hayes 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.5

FeS, as a natural reduced iron mineral, has been recognized to be a viable reactive material for As(III) sequestration in natural and engineered systems. In this study, FeS-coated sand packed columns were tested to evaluate the As(III) removal capacities under anaerobic conditions at pH 5, 7 and 9. The column obtained As(III) removal capacity was then compared with the capacity result obtained from batch reactors. In the comparison, two different approaches were used. The first approach was used the total As(III) removal capacity which method was proved to be useful for interpreting pH 5 system. The second approach was used to consider sorption non-linearity and proved to be useful for interpreting the pH 9. The results demonstrated that a mechanistic understanding of the different removal processes at different pH conditions is important to interpret the column experimental results. At pH 5, where the precipitation of arsenic sulfide plays the major role in the removal of arsenic, the column shows a greater removal efficiency than the batch system due to the continuous dissolution of sulfide and precipitation of arsenic sulfide. At pH 9, where adsorption mainly governs the arsenic removal, the sorption nonlinearity should be considered in the estimation of the column capacity. This study highlighted the importance of understanding reaction mechanism to predict column performance using batch-obtained experimental results.

The FMRFamide Neuropeptide FLP-20 Acts as a Systemic Signal for Starvation Responses in Caenorhabditis elegans

Kang, Chanhee,Avery, Leon Korean Society for Molecular and Cellular Biology 2021 Molecules and cells Vol.44 No.7

Most animals face frequent periods of starvation throughout their entire life and thus need to appropriately adjust their behavior and metabolism during starvation for their survival. Such adaptive responses are regulated by a complex set of systemic signals, including hormones and neuropeptides. While much progress has been made in identifying pathways that regulate nutrient-excessive states, it is still incompletely understood how animals systemically signal their nutrient-deficient states. Here, we showed that the FMRFamide neuropeptide FLP-20 modulates a systemic starvation response in Caenorhabditis elegans. We found that mutation of flp-20 rescued the starvation hypersensitivity of the G protein β-subunit gpb-2 mutants by suppressing excessive autophagy. FLP-20 acted in AIB neurons, where the metabotropic glutamate receptor MGL-2 also functions to modulate a systemic starvation response. Furthermore, FLP-20 modulated starvation-induced fat degradation in a manner dependent on the receptor-type guanylate cyclase GCY-28. Collectively, our results reveal a circuit that senses and signals nutrient-deficient states to modulate a systemic starvation response in multicellular organisms.