266 research outputs found
Micro-Raman spectroscopic analysis of liquid-liquid phase separation
No full textLiquid-liquid phase separation (LLPS) plays a significant role in various biological processes, including the formation of membraneless organelles and pathological protein aggregation. Although many studies have found various factors that modulate the LLPS process or the liquid-to-solid phase transition (LSPT) using microscopy or fluorescence-based methods, the molecular mechanistic details underlying LLPS and protein aggregation within liquid droplets remain uncharacterized. Therefore, structural information on proteins inside liquid droplets is required to understand the mechanistic link to amyloid formation. In the present study, we monitored droplet formation related to protein fibrillation using micro-Raman spectroscopy in combination with differential interference contrast (DIC) microscopy to study the conformational change in proteins and the hydrogen-bonding (H-bonding) structure of water during LLPS. Interestingly, we found that the O-D stretching band for water (HOD in H2O) inside the droplets exhibited a distinct Raman spectrum from that of the bulk water, suggesting that the time-dependent change in the hydration environment in the protein droplets during the process of LLPS can be studied. These results demonstrate that the superior spatial resolution of micro-Raman spectroscopy offers significant advantages in investigating the molecular mechanisms of LLPS and following LSPT processes.11Nsciescopu
Substituent Effects on the Vibrational Properties of the CN Stretch Mode of Aromatic Nitriles: IR Probes Useful for Time-resolved IR Spectroscopy
No full text© 2021 Wiley-VCH GmbHDeveloping ideal IR probes is essential to understand the structure and dynamics of biomolecules with time-resolved IR spectroscopies and imaging techniques. Especially, nitrile (CN) group has recently been proposed to serve as IR probes of the local environment of proteins. Herein, we investigated the effect of a substituent on the vibrational properties of the benzonitrile. The electron-donating and withdrawing character of p-substituent on benzonitrile are expected to modulate the vibrational frequency, molar extinction coefficient, and vibrational lifetime of CN probe. FT-IR revealed the positive correlation between electron-donating character and the molar extinction coefficient of CN stretch mode. Infrared pump-probe (IR-PP) measurements showed that the vibrational lifetime of CN stretch mode exhibits a relatively weak correlation with the electron-donating strength. Among the investigated samples, 4-dimethylamino benzonitrile with the strongest electron-donating strength shows enhanced absorption and extended vibrational lifetime. Utilizing substituent effects will be a practical strategy to improve the performance of the IR probe.11Nsciescopu
A value chain process model of consumer co-creation activities
No full textWith path-breaking advances in technology, consumers have become more informed, connected, and empowered than ever before in hypermedia computer-mediated environments (CMEs). No longer passive recipients in the value creation process, consumers are increasingly active participants co-creating value through interactions with companies and other stakeholders. This has also triggered theoretical evolutions in the marketing discipline, extending from exchange to value creation to value co-creation paradigm. Now, value co-creation has emerged as the central theme in contemporary marketing with a growing body of literature to advance our understanding around the concept. However, there is lack of consensus on the definition, theoretical domains, or process of value co-creation, creating a need to provide an integration of the different existing perspectives around the concept in the literature with empirical validation of the process. By integrating two primary theoretical perspectives on co-creation in the literature (technology and innovation management perspective and service science perspective), my dissertation examines the antecedents and consequences of a wide spectrum of consumer value co-creation activities, ranging from pre-launch (i.e. co-ideation, co-test, co-design, and co-finance) to post-launch (co-promotion, co-distribution, co-maintenance, and co-price). The objective of this paper is to empirically examine the entire process of value co-creation from the marketer-initiated co-production efforts, such as B2C and C2C interaction, equity, and knowledge sharing, to consumers’ value-in-use through experience, relationship, customization, and satisfaction across a variety of value co-creation activities. Using the online video gaming industry as a context for data collection, a total of 561 online video game players completed the survey. Survey-based data collected to test the proposed framework was analyzed using structural equation modeling approach. The results show that pre-launch and post-launch co-creation have different sets of significant antecedents and consequences. As for the drivers of dual forms of interaction (B2C and C2C interaction) knowledge sharing has a positive effect on both B2C interaction and C2C interaction while equity positively impacts B2C interaction only. The influence of consumer motivations varies depending on the nature of interactions. While economic motivation is the only primary predictor for B2C interaction, C2C interaction is found to be influenced by social motivation and psychological motivation. As for the consequences of C2C and B2C interactions, they have different effect on consumer participation in pre- and post-launch co-creation activities. C2C interaction has positive effect on both pre- and post-launch co-creation activities, while B2C interaction has direct positive impact only on pre- not on post-launch co-creation activities; yet indirect effect on post-launch co-creation activities through C2C interaction. Interestingly, this indicates that C2C interaction fully mediates the relationship between B2C interaction and consumer participation in post-launch co-creation activities. Consumers’ co-created outcomes (i.e. value-in-use) are influenced differently depending on consumer participation in pre- vs. post-launch stages. While perceived level of customer relationship and satisfaction are highly influenced regardless of the types of consumer co-creation participation, experience is impacted only by post-launch co-creation participation while personalization is impacted only by pre-launch co-creation participation.Ph.D.Includes bibliographical referencesby Kyungwon Le
Parks as a Visionary or Media Device: An Approach of“ Promise Park” by Moon Kyungwon
No full textThis paper deals wite “Promise Park,” a project initiated by a team including Korean artist Moon Kyungwon and the author himself. “Promise Park” raises the question of what future parks would look like, why parks have existed in the history of civilization, and what kind of role they serve within the urban structure. It approximates the park-like space as a whole, exploring topics such as the motifs and influences parks have carried within modern and contemporary art history, their relation to their predecessor of gardens, and their significance as voids within public spaces.departmental bulletin pape
Life Satisfaction, Occupation and Gender
No full textThis study aims to understand the impacts of wages and occupational prestige on life satisfaction among wage workers by occupation and gender in South Korea using data from the Korea Labor and Income Panel Study (KLIPS) and analyzing it with a fixed effects ordered logit analysis. The results show that wage positively affects life satisfaction for both male and female workers but that it matters more for women. The effects are also different by occupation. Wage is more significant in the life satisfaction of male managers and clerks. Regarding prestige, it has no significant impact on the life satisfaction of male workers, but it affects female workers. By occupation, it matters more for managers, professionals, and semi-professionals but for clerks, it does not affect much among male employees. On the other hand, it dominates all occupations among female workers, so the differences in life satisfaction by occupation amongst women can be said to be mainly due to occupational prestige.1
Molecular Mechanism of Selective Al2O3 Atomic Layer Deposition on Self-Assembled Monolayers
No full textArea-selective atomic layer deposition (AS-ALD) of insulatingmetallicoxide layers could be a useful nanopatterning technique for makingincreasingly complex semiconductor circuits. Although the alkanethiolself-assembled monolayer (SAM) has been considered promising as anALD inhibitor, the low inhibition efficiency of the SAM during ALDprocesses makes its wide application difficult. We investigated thedeposition mechanism of Al2O3 on alkanethiol-SAMsusing temperature-dependent vibrational sum-frequency-generation spectroscopy.We found that the thermally induced formation of gauche defects inthe SAMs is the main causative factor deteriorating the inhibitionefficiency. Here, we demonstrate that a discontinuously temperature-controlledALD technique involving self-healing and dissipation of thermallyinduced stress on the structure of SAM substantially enhances theSAM's inhibition efficiency and enables us to achieve 60 ALDcycles (6.6 nm). We anticipate that the present experimental resultson the ALD mechanism on the SAM surface and the proposed ALD methodwill provide clues to improve the efficiency of AS-ALD, a promisingnanoscale patterning and manufacturing technique.11Nsciescopu
Ultrafast intraband Auger process in self-doped colloidal quantum dots
No full textInvestigating the separate dynamics of electrons and holes has been challenging, although it is critical for the fundamental understanding of semiconducting nanomaterials. n-Type self-doped colloidal quantum dots (CQDs) with excess electrons occupying the low-lying state in the conduction band (CB) have attracted a great deal of attention because of not only their potential applications to infrared optoelectronics but also their intrinsic system that offers a platform for investigating electron dynamics without elusive contributions from holes in the valence band. Here, we show an unprecedented ultrafast intraband Auger process, electron relaxation between spin orbit coupling states, and exciton-to-ligand vibrational energy transfer process that all occur exclusively in the CB of the self-doped beta-HgS CQDs. The electron dynamics obtained by femtosecond mid infrared spectroscopy will pave the way for further understanding of the blinking phenomenon, disproportionate charging in light-emitting diodes, and hot electron dynamics in higher quantum states coupled to surface states of CQDs.11Nsciescopu
Thermoresponse of Odd-Even Effect in n-Alkanethiolate Self-Assembled Monolayers on Gold Substrates
No full textThis study examines thermoresponse of odd-even effect in self-assembled monolayers (SAMs) of n-alkanethiolates (SCn, n=3-18) formed on template-stripped gold (Au-TS) using macro- and microscopic analytical techniques, contact angle goniometry (CAG) and vibrational sum frequency generation (VSFG) spectroscopy, respectively. Both CAG and VSFG analyses showed that the odd-even effect in liquid-like SAMs (n=3-9) disappeared upon heating at 50-70 degrees C, indicating that the heating led to increased structural disorder regardless of odd and even carbon numbers. In contrast, the opposite thermoresponse was observed for odd and even SCn molecules in wax- and solid-like SAMs (n=10-18). Namely, temperature-dependent orientational change of terminal CH3 relative to the surface normal was opposite for the odd and even molecules, thereby leading to mitigated odd-even effect. Our work offers important insights into thermoresponse of supramolecular structure in condensed organic matter.11Nsciescopu
DNA microarray-based identification of bacterial and fungal pathogens in bloodstream infections
No full textThe accurate and rapid identification of pathogens in blood is a major challenge in clinical pathogen diagnostics because of the high mortality of sepsis. Here we report the development of DNA microarray for the identification of pathogens causing bloodstream infections. Species-specific and bacteria- and fungi-broad-ranged probes were designed to identify 50 bacteria and 7 fungi. The specificities and sensitivities of the selected probes were successfully validated by applying reference strains. To assess the performance of the DNA microarray in a clinical setting, blind tests were performed using 112 blood culture specimens that showed preliminary presence of pathogenic microorganisms by culture-based method, resulting in the correct identification of pathogens in 104 samples showing the sensitivity of 93%. In addition, closely-related species could be discriminated by the distinct hybridization patterns. This DNA microarray-based pathogen diagnosis takes approximately 10 h starting from a positive blood culture, considerably reducing time required to sufficiently identify pathogens by subsequent agar-culture and biochemical tests which requires altogether at least 1-3 days. Also, the amount of sample required for the identification of pathogens is much less than that required for biochemical assays. Thus, the DNA microarray reported here should be useful for the effective identification of microbial pathogens in blood cultures from septicemic patients. (C) 2009 Elsevier Ltd. All rights reserved.This work was supported by the Korean Systems Biology Project
from the Ministry of Education, Science and Technology. Further
supports by Medigenes Co. and LG Chem Chair Professorship are
appreciated
Way to deal with market uncertainty in real estate development projects
No full textThesis (S.M. in Real Estate Development)--Massachusetts Institute of Technology, Dept. of Architecture, Center for Real Estate, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (leaves 64-65).The practice of applying options theory to real estate investments has only recently begun. In particular, options in real estate are called "real options." Real options add value to real estate development projects by allowing developers to take advantage of positive aspects of the market and avoid negative conditions. There has not been much effort to rigorously quantify the value of applying flexibility to real-world development projects. In this paper, I will attempt to examine the impact of applying real options theory to a mixed-use development project, the "Parcl project," which consists of two office towers, a hotel, and a retail mall to gain better understanding of flexibility. This project is being constructed all at once based on predetermined assumptions about factors like rental rolls, sales price, and constructions costs. However, the deterministic model could result in a loss in case market conditions do not meet the assumptions set at the beginning. In this sense, applying real options such as phasing, deferring, and abandoning would be one of the ways to absorb the uncertainties in the market. This paper will try to figure out how much value real options can add to the project in terms of dealing with market conditions. For the analysis, the quantitative methods such as an engineering model and Monte Carlo simulation will be used.by Kyungwon Kim.S.M.in Real Estate Developmen
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