• Molecules and Cells
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• 제21권1호
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• pp.7-20
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• 2006

The major event in human immunodeficiency virus type 1 (HIV-1) infection is the death of many cells related to host immune response. The demise of these cells is normally explained by cell suicide mechanism, apoptosis. Interestingly, the decrease in the number of immune cells, such as non-CD4+ cells as well as CD4+ T cells, in HIV infection usually occurs in uninfected bystander cells, not in directly infected cells. It has, therefore, been suggested that several soluble factors, including viral protein R (Vpr), are released from the infected cells and induce the death of bystander cells. Some studies show that Vpr interacts directly with adenine nucleotide translocator (ANT) to induce mitochondrial membrane permeabilization (MMP). The MMP results in release of some apoptogenic factors such as cytochrome-c (cyt-c) and apoptosis-inducing factor (AIF). Vpr also has indirect effect on mitochondria through enhancing the level of caspase-9 transcription and suppressing nuclear factor-kappa B (NF-${\kappa}B$). The involvement of p53 in Vpr-induced apoptosis remains to be studied. On the other hand, low level of Vpr expression has anti-apoptotic effect, whereas it's high level of expression induces apoptosis. Extracellular Vpr also exhibits cytotoxicity to uninfected bystander cells through apoptotic or necrotic mechanism. The facts that Vpr has cytotoxic effect on both infected cells and bystander cells, and that it exhibits both proand anti-apoptotic activity may explain its role in viral survival and disease progression.

• 한국토양비료학회지
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• 제19권3호
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• pp.251-268
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• 1986

Selecting a site for the safe disposal of radioactive waste requires the evaluation of a wide range of geologic, mineralogic, hydrologic, and physicochemical properties. Although highly diverse, these properties are in fact interrelated. Site requirements are also diverse because they are influenced by the nature of the radionuclides in the waste, for example, their half-lives, specific energy, and chemistry. A fundamental consideration in site selection is the mineralogy of the host rock, and one of the most ubiquitous mineral groups is clay minerals. Clays and clay minerals as in situ lithologic components and engineered barriers may playa significant role in retarding the migration of radionuclides. Their high sorptivity, longevity (stability), low permeability, and other physical factors should make them a very effective retainer of most radionuclides in nuclear wastes. There are, however, some unanswered questions. For example, how will their longevity and physicochemical properties be influenced by such factors as radionuclide concentration, radiation intensity, elevated temperatures, changes in redox condition, pH, and formation fluids for extended periods of time? Understanding of mechanisms affecting clay mineral-radionuclide interactions under prevailing geochemical conditions is important; however, the utilization of experimental geochemical information related to physicochemical properties of clays and clay-bearing materials with geohydrologic models presents a uniquely challenging problem in that many assessments have to be based on model predictions rather than on experiments. These are high-priority research investigations that need to be addressed before complete reliance for disposal area performance is made on clays and clay minerals.

• The Journal of Asian Finance, Economics and Business
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• 제8권10호
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• pp.187-196
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• 2021

Vietnam has become one of the largest markets in Southeast Asia, with huge demand for many kinds of consumer goods, including dairy products. Although the domestic industry of producing and distributing milk has flourished dramatically in recent years, Vietnam still heavily hinges on dairy imports. The total value of milk products in 2020 exceeded 1 billion USD, leading to Vietnam being one of the 20 biggest importers of dairy milk globally. To explore this potential industry, we applied a multivariate linear regression model to investigate the milk consumption behaviors of Vietnamese adults. 2000 participants took part in our survey in which the products evaluated were Dielac Alpha - the most famous national powdered milk introduced in 2007 by Vinamilk. This product was designed for all ages, from children aged 0-6 to pregnant women or adults. The results indicate that the decision to purchase milk could be attributed to a host of factors. While price represents the most strongly influential factor, there might be variations according to consumer characteristics, namely age, marriage status, gender, and particular shopping behavior. From these findings, we propose some managerial implications for regulatory bodies and relevant enterprises to prepare appropriate policies and strategies for their business development.

• Journal of Forest and Environmental Science
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• 제35권3호
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• pp.189-196
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• 2019

Plants are consumed by a myriad of organisms that compete for resources. Direct interactions among multiple plant-feeding organisms in a single host can range for each species from positive to negative. Wood-boring beetle faces a number of biotic and abiotic constraints that interfere with the good prospects from the tree. Biotic factors, including arthropod pests and diseases, and abiotic factors, such as drought and water-logging, are the major constraints affecting the species. The present study aimed to provide basic data for analyzing forest health, identify the kinds of wood-boring beetles in the central part of Korea. Our second goal was to analyze the species composition and diversity of regional communities and to examine. A total of 10,461 individual wood-boring beetles belonging to 8 families and 50 species attracted to trap trees in the pine forests were recorded during the study period on study sites. The results of the analysis of collected species showed that the community structure on all study sites was similar. Seasonal occurrences of dominant wood-boring beetles (5 species) from each study site showed the highest number of all species, except for Siphalinus gigas in May, followed by a gradual decline, and the largest number of Siphalinus gigas appeared in June. The similarity index of species composition was relatively high, ranging from 0.75 to 0.90 for each study site.

• Tuberculosis and Respiratory Diseases
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• 제82권2호
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• pp.94-101
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• 2019

Nontuberculous mycobacteria (NTM) are ubiquitous organisms that are generally found not only in the natural environment but also in the human engineered environment, including water, soil, and dust. These organisms can form biofilms and can be readily aerosolized because they are hydrophobic owing to the presence of the lipid-rich outer membrane. Aerosolization and subsequent inhalation were the major route of NTM lung disease. Water distribution systems and household plumbing are ideal habit for NTM and the main transmission route from natural water to household. NTM have been isolated from drinking water, faucets, pipelines, and water tanks. Studies that used genotyping have shown that NTM isolates from patients are identical to those in the environment, that is, from shower water, showerheads, tap water, and gardening soil. Humans are likely to be exposed to NTM in their homes through simple and daily activities, such as drinking, showering, or gardening. In addition to environmental factors, host factors play an important role in the development of NTM lung disease. The incidence and prevalence of NTM lung disease are increasing worldwide, and this disease is rapidly becoming a major public health problem. NTM lung disease is associated with substantially impaired quality of life, increased morbidity and mortality, and high medical costs. A more comprehensive understanding of the infection source and epidemiology of NTM is essential for the development of new strategies that can prevent and control NTM infection.

• Animal Bioscience
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• 제34권3_spc호
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• pp.321-337
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• 2021

The global population has increased with swift urbanization in developing countries, and it is likely to result in a high demand for animal-derived protein-rich foods. Animal farming has been constantly affected by various stressful conditions, which can be categorized into physical, environmental, nutritional, and biological factors. Such conditions could be exacerbated by banning on the use of antibiotics as a growth promoter together with a pandemic situation including, but not limited to, African swine fever, avian influenza, and foot-and-mouth disease. To alleviate these pervasive tension, various immunomodulants have been suggested as alternatives for antibiotics. Various studies have investigated how stressors (i.e., imbalanced nutrition, dysbiosis, and disease) could negatively affect nutritional physiology in chickens. Importantly, the immune system is critical for host protective activity against pathogens, but at the same time excessive immune responses negatively affect its productivity. Yet, comprehensive review articles addressing the impact of such stress factors on the immune system of chickens are scarce. In this review, we categorize these stressors and their effects on the immune system of chickens and attempt to provide immunomodulants which can be a solution to the aforementioned problems facing the chicken industry.

• Asian Journal of Business Environment
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• 제14권1호
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• pp.1-13
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• 2024

Purpose: This study explores the level of relevance of liability of foreignness (LOF) in foreign firms' decision to relocate or to expand their regional headquarters (RHQ) in Singapore. Research design, data and methodology: The research question is: what are the mitigating factors of LOF for RHQs operating in Singapore? This explorative study uses various resources from the government agencies: Singapore Economic Development Board such as annual reports between 2012 and 2022, investment programs and published interviews with RHQ's CEOs, Singapore Department of Statistics such as economic, socio-economic and investment data. Results: My study shows that years of nation-building toward a world-class infrastructure, identifying key-industries and conscientiously enhancing workforce skills and competency, developing and reviewing investment programs to attract and retain RHQs were the mitigating factors of LOF. Conclusion: This implies a low level of relevance of LOF in foreign firms' strategic choice to relocate or to expand their regional headquarters to Singapore. As such, the steady growth of multinational enterprises' (MNEs) RHQs in Singapore presents a challenge to the theoretical postulation of LOF positing that foreign firms are discriminated in host country-environment. As a result, incurring additional costs operating in an unfamiliar environment manifested by varying responses from the local actors. Singapore is a case in point.

• 환경생물
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• 제17권4호
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• pp.467-479
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• 1999

충청북도 옥천군 지역의 붉은점모시나비에 대한 소멸원인과 복원방안을 조사하였다. 붉은점모시나비는 과거 중부지역인 옥천군에서 비교적 많은 개체가 발생하였으나, 그 수가 계속 감소하여 1997에는 두 마리의 성충만 확인되었고, 1998년에는 확인되지 않았다. 따라서 현재 옥천군지역에서 붉은점모시나비는 소멸된 것으로 추정된다. 붉은점모시나비의 소멸원인을 알아보기 위하여 1990∼1998년간 옥천군 7곳의 서식지에 대한 조사 기록의 분석과 여러기관에 소장된 표본 252개체의 채집기록을 조사하였다. 그 결과, 도로 개설에 의한 서식지의 급격한 환경 변화와 빈번한 채집이 붉은점모시나비의 소멸원인으로 나타났다. 옥천군 지역에 붉은점모시나비의 복원을 위한 프로그램으로 우선적으로 사육을 통한 붉은점모시나비의 생활사를 정리하였고, 둘째로 복원을 위한 최적지를 선정하기 위하여 서식이 확인되었던 7개 지역에 대한 서식지 환경조건을 비교·분석하였다. 복원적정지역은 섭식식물의 생육환경이 좋은 동낙정과 장화리로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.946-956
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• 2018

The gut microbiota of aquatic animals plays a crucial role in host health through nutrient acquisition and outcompetition of pathogens. In this study, on the basis of the high-throughput sequencing of 16S rRNA gene amplicons, we examined the bacterial communities in the gut of freshwater shrimp (Macrobrachium nipponense) and in their living environments (sediment and pond water) and analyzed the effects of abiotic and biotic factors on the shrimp gut bacterial communities. High bacterial heterogeneity was observed in the freshwater shrimp gut samples, and the result indicated that both the surrounding bacterial community and water quality factors (particularly dissolved oxygen and temperature) could affect the shrimp gut bacterial community. Despite the observed heterogeneity, 57 genera, constituting 38-99% of the total genera in each of the 40 shrimp gut samples, were identified as the main bacterial population in the gut of M. nipponense. In addition, a high diversity and abundance of lactic acid bacteria (26 genera), which could play significant roles in the digestion process in shrimp, were observed in the shrimp gut samples. Overall, this study provides insights into the gut bacterial communities of freshwater shrimp and basic information for shrimp farming regarding the application of probiotics and disease prevention.

• Journal of Korea Trade
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• 제26권4호
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• pp.83-97
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• 2022

Purpose - In this paper, we, taking South Korea's foreign direct investment in RCEP partners as an example, will examine its investment efficiency in these countries and analyze the main influencing factors, making suggestions for further liberalizing and facilitating its investment in and even for promoting its trade and economic cooperation with them. Design/methodology - In this study, we look at the panel data of South Korea and the other 13 RCEP countries (Brunei excluded) from 2000 to 2019 and apply the stochastic frontier analysis to measure its foreign direct investment efficiency and explore the influencing factors in RCEP countries. We examine the investment potential of South Korea in these places. Findings - We find that South Korea's average investment efficiency in RCEP countries reached 0.62, indicating large investment potential. We also find that its investment efficiency in RCEP partners was heterogeneous. Our study reveals that South Korea's foreign direct investment is significantly positively correlated with the market size and population of the two countries, as well as with whether the host country has a coastline and rich natural resources, while negatively with geographic distance. It shows that free trade agreements, economic freedom, and regulatory quality play significant roles in improving investment efficiency. Originality/value - Through theoretical and empirical analysis, we deal with the efficiency and influencing factors of South Korea's direct investment in RCEP partners, proposing new drivers for facilitating its trade and investment in these countries and comprehensively evaluating the efficiency and revealing the trend of its FDI in these countries. In this paper, we put forward a solid theoretical basis for empirical analysis of the future economic and trade development between South Korea and its RCEP partners and give objective insights for further improving its foreign direct investment efficiency and tapping its investment potential.