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"Mahn, Mahn"
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Mask sociology as a way of action theory: Voices of the face mask among social individuals in the COVID-19 masquerade in South Korea
South Koreans are susceptible to the medical face mask against the COVID-19 pandemic. Meanwhile, their mask practices are intriguingly laden with contradictions and inconsistencies. This study accounts for this puzzle by expanding two sociological frontiers: the sociology of action (i.e., action theory of agency and individuality) and the sociology of the mask. Drawing on action theory, it stresses that contradictions and inconsistencies reveal the nature of individuals as social individuals and develops a typology of social individuals during the current pandemic (i.e., atomists, collectivists, and dualists). For mask sociology, it amplifies that any mask practices are conceptualized as a masquerade involving multiple elements for individuality and proposes a theory of mask multivocality that appreciates the ways in which masquerade the social drama becomes concretized. With this two-pronged conceptual innovation, it first demonstrates a patterned relationship between social individuals and mask multivocality. Dualists take more voices from the mask than atomists or collectivists. Dualists take the most contradictory voices as well. Second, it shows that Koreans who take more meanings from the mask reveal not only more vulnerability but more transformative power amid the current pandemic. Demonstrating the promise of mask sociology for the action theory of individuality, it ultimately argues that individuals as social performers often reveal themselves as mask-wearers who become as transformative as they are vulnerable. While this model is founded upon the recent pandemic, it ramifies in political and cultural events that various face coverings accompany.
Journal Article
Potential of Sulforaphane as a Natural Immune System Enhancer: A Review
Brassicaceae are an outstanding source of bioactive compounds such as ascorbic acid, polyphenols, essential minerals, isothiocyanates and their precursors, glucosinolates (GSL). Recently, GSL gained great attention because of the health promoting properties of their hydrolysis products: isothiocyanates. Among them, sulforaphane (SFN) became the most attractive one owing to its remarkable health-promoting properties. SFN may prevent different types of cancer and has the ability to improve hypertensive states, to prevent type 2 diabetes–induced cardiomyopathy, and to protect against gastric ulcer. SFN may also help in schizophrenia treatment, and recently it was proposed that SFN has potential to help those who struggle with obesity. The mechanism underlying the health-promoting effect of SFN relates to its indirect action at cellular level by inducing antioxidant and Phase II detoxifying enzymes through the activation of transcription nuclear factor (erythroid-derived 2)-like (Nrf2). The effect of SFN on immune response is generating scientific interest, because of its bioavailability, which is much higher than other phytochemicals, and its capacity to induce Nrf2 target genes. Clinical trials suggest that sulforaphane produces favorable results in cases where pharmaceutical products fail. This article provides a revision about the relationship between sulforaphane and immune response in different diseases. Special attention is given to clinical trials related with immune system disorders.
Journal Article
Coordinating and competing in ecosystems: How organizational forms shape new technology investments
We consider firms in the context of their business ecosystems and explore how differences in the ways in which firms are organized with respect to complementary activities affect their decision to invest in new technologies. We argue that, in addition to creating differences in incentives and bureaucratic costs, firm-complementor organizational form plays an important role in the firm's ability to coordinate accompanying changes in complementary activities so as to shape the benefits from investing early in the new technology. We test our predictions in the U.S. healthcare industry from 1995—2006. The study makes a strong case for viewing firms' competitive strategies in the context of their business ecosystems and for the existence of an important link between firms' coordination choices and their strategic investments.
Journal Article
Spatial practices : territory, border and infrastructure in Africa
This edited collection presents research findings from the German Research Council's Priority Programme 1448 \"Adaptation and Change in Africa\" (2011-2018). At the heart of the volume are important new spatial practices that have emerged after the end of the Cold War in the fields of conflict, climate change, migration and urban development, to name but a few, and their ordering effects with regard to social relations. These findings bear particular relevance for the co-production of territorialities and sovereignties, for borders and migrations, as well as infrastructures and orders.
Book
ARE FOUNDER CEOS MORE OVERCONFIDENT THAN PROFESSIONAL CEOS? EVIDENCE FROM S&P 1500 COMPANIES
Research summary: We provide evidence that founder chief executive officers (CEOs) of large S&P 1500 companies are more overconfident than their nonfounder counterparts (\"professional CEOs\"). We measure overconfidence via tone of CEO tweets, tone of CEO statements during earnings conference calls, management earnings forecasts, and CEO option-exercise behavior. Compared with professional CEOs, founder CEOs use more optimistic language on Twitter and during earnings conference calls. In addition, founder CEOs are more likely to issue earnings forecasts that are too high; they are also more likely to perceive their firms to be undervalued, as implied by their option-exercise behavior. We provide evidence that, to date, investors appear unaware of this \"overconfidence bias\" among founders. Managerial summary: This article helps to explain why firms managed by founder chief executive officers (CEOs) behave differently from those managed by professional CEOs. We study a sample of S&P 1500 firms and find strong evidence that founder CEOs are more overconfident than professional CEOs. To date, investors appear unaware of this overconfidence bias among founders. Our study should help firm stakeholders, including investors, employees, suppliers, and customers, put the statements and actions of founder CEOs in perspective. Our study should also help members of corporate boards make more informed decisions about whether to retain (or bring back) founder CEOs or hire professional CEOs.
Journal Article
Zero-reflection acoustic metamaterial with a negative refractive index
Waves are reflected to varying degrees at the boundary between two different media. A reduction of this reflection is important for many materials, including acoustic metamaterials. Here, we theoretically develop a balanced acoustic metamaterial that exhibits zero reflection between the metamaterial and air over its entire refractive index range, regardless of the sign of the refractive index. The metamaterial is realized using unit cell structures containing membranes and open tubes, and the material performance is verified experimentally, demonstrating sound reflectance of less than 10% in the frequency region that satisfies the homogeneous medium condition. The zero-reflection characteristic of the acoustic balanced metamaterial can improve the performance of new acoustic devices such as the invisibility cloak and super-lens and can also contribute to basic research of acoustic metamaterials.
Journal Article
Differentiation of Human Pluripotent Stem Cells into Nephron Progenitor Cells in a Serum and Feeder Free System
Kidney disease is emerging as a critical medical problem worldwide. Because of limited treatment options for the damaged kidney, stem cell treatment is becoming an alternative therapeutic approach. Of many possible human stem cell sources, pluripotent stem cells are most attractive due to their self-renewal and pluripotent capacity. However, little is known about the derivation of renal lineage cells from human pluripotent stem cells (hPSCs). In this study, we developed a novel protocol for differentiation of nephron progenitor cells (NPCs) from hPSCs in a serum- and feeder-free system.
We designed step-wise protocols for differentiation of human pluripotent stem cells toward primitive streak, intermediate mesoderm and NPCs by recapitulating normal nephrogenesis. Expression of key marker genes was examined by RT-PCR, real time RT-PCR and immunocytochemistry. Each experiment was independently performed three times to confirm its reproducibility.
After modification of culture period and concentration of exogenous factors, hPSCs can differentiate into NPCs that markedly express specific marker genes such as SIX2, GDNF, HOXD11, WT1 and CITED1 in addition to OSR1, PAX2, SALL1 and EYA1. Moreover, NPCs possess the potential of bidirectional differentiation into both renal tubular epithelial cells and glomerular podocytes in defined culture conditions. In particular, approximately 70% of SYN-positive cells were obtained from hPSC-derived NPCs after podocytes induction. NPCs can also form in vitro tubule-like structures in three dimensional culture systems.
Our novel protocol for hPSCs differentiation into NPCs can be useful for producing alternative sources of cell replacement therapy and disease modeling for human kidney diseases.
Journal Article