A Multifaceted Phenomenon of Hydrophobic Effects: Insights Learned from Nucleation Algorithm Based Computer Simulation Approach

We have applied our new approach, a combination of the AVUS-HR nucleation algorithm and a thermodynamic cycle, to the studies of hydrophobicity-related researches. Due to the multifaceted characteristics of hydrophobicity, it is essential to acquire knowledge in various environments where hydrophobic relevant events occur for comprehensive understanding of this process. In this regards, we have chosen two relatively unstudied hydrophobic subjects for application of our new methodology. For the first subject, hydrophobic association behaviors of a methane pair confined into a nanometer sized hydrophobic cavity have been investigated. Our new approach demonstrates that the association behavior between two methane molecules is enhanced under confined environment rather than in bulk water. This association is primarily driven by energy originating from the unique situation where small (i.e., two methane molecules) and large (i.e., boundary of the hydrophobic cavity) hydrophobic units come together. For the second subject, hydration thermodynamics for confined spaces between two infinitely parallel walls have been studied. Our simulation results demonstrate that the weak attractive interaction between water molecules and walls allows water molecules to pack more efficiently for the smallest wall separation of 3 Å considered here comparing with the hard wall case where there is no interaction between water molecules and walls. Furthermore, these weak attractive interactions lower the free energy penalty for the formation of water clusters inside a confined space, ultimately lowering the total energy of the system when compared with the hard wall. Based on the successful applications of our novel nucleation algorithm to the two different hydrophobic related researches, further, we believe that it will contribute to the various and more complex hydrophobic researches (i.e., association behaviors of nonpolar and/or polar amino acid residues in the presence of salts under confined environment, and effects of salts, temperature and pressure on this association behaviors) as well as nucleation studies under confined environment

Corporate Image and Reputation in the Shipping Industry in Four Asian Countries: Republic of Korea, China, Japan, and Thailand

This study aims to analyze the perceptions regarding shipping companies corporate image and reputation in Republic of Korea, China, Japan, and Thailand. For this study, the shipping industry is confined to the bulk and container shipping sectors to prevent confusion arising from the different sectors. An international questionnaire survey was administered in each country. The participants were asked to report their perceptions on eight indicators of corporate image and seven indicators of corporate reputation relating to the shipping companies. Descriptive analyses and a one-way between-groups analysis of variance (ANOVA) were conducted using SPSS 20. Findings show that there are significant differences in perceptions concerning corporate image and reputation among four countries. Some cases show significant differences in the analyses in line with demographic characteristics. While China shows the highest scores in most variables, Korea is revealed to have the lowest scores. The results indicate the need to develop programs for improving the external positive perceptions of the shipping companies, as well as to broaden the scope of marketing activities targeting the general public. This study is of critical importance as it discusses relatively ignored but important issues by conducting comparative research in four major Asian countries comprehensively, particularly targeting samples rarely considered in the empirical shipping-related studies despite their significance to academic development. Further research is required to demonstrate the effectiveness of the findings by applying the measures in different national contexts with a more diverse group of samples

How people perceive malicious comments differently: factors influencing the perception of maliciousness in online news comments

This study proposes a comprehensive model to investigate the factors that influence the perceived maliciousness of online news comments. The study specifically examines individual factors, including demographic characteristics (e.g., gender and age), personality traits (e.g., empathy and attitudes toward online news comments), and reading-related factors (e.g., the amount of news comment reading). Contextual factors such as issue involvement, perceived peer behavior, and the presence of malicious comments in news articles are also considered. The results suggest that most of the proposed variables have a significant impact on the perceived maliciousness of online news comments, except for morality and issue involvement. The findings have important theoretical implications for research on malicious online news comments and provide practical guidelines for online news platforms on how to reduce malicious comments by visualizing them alongside other news comments

Language assessment in Wada test: Comparison of methohexital and amobarbital

AbstractIntroductionMethohexital has replaced amobarbital during Wada testing at many centers. The objective of our study was to compare the use of methohexital and amobarbital during Wada testing regarding language and memory lateralization quotients as well as speech arrest times.MethodsA chart review of 582 consecutive patients undergoing 1041 Wada-procedures was performed (left=60, right=63, bilateral=459). Language lateralization was calculated based on duration of speech arrest using a laterality index, defined as (L−R)/(L+R). Memory lateralization was expressed as percentage of retained objects and laterality quotient.ResultsLanguage and memory lateralization revealed a similar distribution with amobarbital and methohexital. Speech arrest after left and right-sided injection was significantly longer in the amobarbital group as compared to the methohexital group. Language lateralization did not differ in the two groups. Percentage of retained memory items was higher in the methohexital group and there were fewer presented test items in the methohexital group.DiscussionLanguage and memory testing during the Wada test can successfully be performed with methohexital instead of amobarbital. The shorter half-life of methohexital allows repeated injections and shorter interhemispheric testing intervals, but also shortens the testing window

Metallicity-PAH Relation of MIR-selected Star-forming Galaxies in AKARI North Ecliptic Pole-wide Survey

We investigate the variation in the mid-infrared spectral energy distributions of 373 low-redshift ($z<0.4$) star-forming galaxies, which reflects a variety of polycyclic aromatic hydrocarbon (PAH) emission features. The relative strength of PAH emission is parameterized as $q_\mathrm{PAH}$, which is defined as the mass fraction of PAH particles in the total dust mass. With the aid of continuous mid-infrared photometric data points covering 7-24$\mu$m and far-infrared flux densities, $q_\mathrm{PAH}$ values are derived through spectral energy distribution fitting. The correlation between $q_\mathrm{PAH}$ and other physical properties of galaxies, i.e., gas-phase metallicity ($12+\mathrm{log(O/H)}$), stellar mass, and specific star-formation rate (sSFR) are explored. As in previous studies, $q_\mathrm{PAH}$ values of galaxies with high metallicity are found to be higher than those with low metallicity. The strength of PAH emission is also positively correlated with the stellar mass and negatively correlated with the sSFR. The correlation between $q_\mathrm{PAH}$ and each parameter still exists even after the other two parameters are fixed. In addition to the PAH strength, the application of metallicity-dependent gas-to-dust mass ratio appears to work well to estimate gas mass that matches the observed relationship between molecular gas and physical parameters. The result obtained will be used to calibrate the observed PAH luminosity-total infrared luminosity relation, based on the variation of MIR-FIR SED, which is used in the estimation of hidden star formation.Comment: 19 pages, 9 figures, AJ, in pres

Identification of new CYP2C19 variants exhibiting decreased enzyme activity in the metabolism of S-mephenytoin and omeprazole. Drug Metab

ABSTRACT: Although many cases of interindividual variation in the metabolism of CYP2C19 drugs are explained by the CYP2C19*2, *3, and *17, a wide range of metabolic variation still occurs in people who do not carry these genetic variants. The objectives of this study were to identify new genetic variants and to characterize functional consequences of these variants in metabolism of CYP2C19 substrates. In total, 21 single-nucleotide polymorphisms including three new coding variants, V394M, E405K, and D256N, were identified by direct DNA sequencing in 50 randomly selected subjects and in individuals who exhibited an outlier phenotype response in the omeprazole study. Recombinant proteins produced from the coding variants V394M, E405K, and D256N were prepared by using an Escherichia coli expression system and purified. Metabolism of S-mephenytoin and omeprazole by V394M was comparable with that of the wild-type protein. E405K showed a moderate decrease in metabolism of the substrates. However, D256N exhibited a significantly decreased activity in S-mephenytoin metabolism, resulting in 50 and 76% decreases in V max and intrinsic clearance, respectively, compared with the wild type. This variant also exhibited a significant decrease in omeprazole metabolism in vivo. CYP2C19 D256N and E405K were assigned as CYP2C19*26 and *2D, respectively, by the Cytochrome P450 Nomenclature Committee. In summary, this report characterizes the allele frequency and haplotype distribution of CYP2C19 in a Korean population and provides functional analysis of new coding variants of the CYP2C19 gene. Our findings suggest that individuals carrying CYP2C19*26 would have lower activity for metabolizing CYP2C19 substrate drugs

Facile and versatile ligand analysis method of colloidal quantum dot

Colloidal quantum-dots (QDs) are highly attractive materials for various optoelectronic applications owing to their easy maneuverability, high functionality, wide applicability, and low cost of mass-production. QDs usually consist of two components: the inorganic nano-crystalline particle and organic ligands that passivate the surface of the inorganic particle. The organic component is also critical for tuning electronic properties of QDs as well as solubilizing QDs in various solvents. However, despite extensive effort to understand the chemistry of ligands, it has been challenging to develop an efficient and reliable method for identifying and quantifying ligands on the QD surface. Herein, we developed a novel method of analyzing ligands in a mild yet accurate fashion. We found that oxidizing agents, as a heterogeneous catalyst in a different phase from QDs, can efficiently disrupt the interaction between the inorganic particle and organic ligands, and the subsequent simple phase fractionation step can isolate the ligand-containing phase from the oxidizer-containing phase and the insoluble precipitates. Our novel analysis procedure ensures to minimize the exposure of ligand molecules to oxidizing agents as well as to prepare homogeneous samples that can be readily analyzed by diverse analytical techniques, such as nuclear magnetic resonance spectroscopy and gas-chromatography mass-spectrometry. © 2021, The Author(s).1

Photometric Selection of Unobscured QSOs in the Ecliptic Poles: KMTNet in the South Field and Pan-STARRS in the North Field

We search for quasi-stellar objects (QSOs) in a wide area of the south ecliptic pole (SEP) field, which has been and will continue to be intensively explored through various space missions. For this purpose, we obtain deep broadband optical images of the SEP field covering an area of $\sim$$14.5\times14.5$ deg$^2$ with the Korea Microlensing Telescope Network. The 5$\sigma$ detection limits for point sources in the $BVRI$ bands are estimated to be $\sim$22.59, 22.60, 22.98, and 21.85 mag, respectively. Utilizing data from Wide-field Infrared Survey Explorer, unobscured QSO candidates are selected among the optically point-like sources using the mid-infrared (MIR) and optical-MIR colors. To further refine our selection and eliminate any contamination not adequately removed by the color-based selection, we perform the spectral energy distribution fitting with archival photometric data ranging from optical to MIR. As a result, we identify a total of 2,383 unobscured QSO candidates in the SEP field. We also apply a similar method to the north ecliptic pole field using the Pan-STARRS data and obtain a similar result of identifying 2,427 candidates. The differential number count per area of our QSO candidates is in good agreement with those measured from spectroscopically confirmed ones in other fields. Finally, we compare the results with the literature and discuss how this work will be implicated in future studies, especially with the upcoming space missions.Comment: 14 pages, 9 figures, accepted for publication in ApJ