Depression before and during-COVID-19 by Gender in the Korean Population.

This study explored the association between Coronavirus disease (COVID-19) and depression by comparing Patient Health Questionnaire-9 (PHQ-9) results pre-pandemic (2019) and after the start of the pandemic (2020). Data of 444,051 participants (200,206 male (45.1%); 243,845 female (54.9%)) were obtained from the Korean Community Health Survey conducted from 2019 to 2020. The independent variable of interest in this study was the year, divided into binary categories, 2019 and 2020. The dependent variable was depression, measured by the PHQ-9 scale. This dependent variable was also binary, dividing those who are considered depressed or not by a cut-off score of 10. A logistic regression model was employed to examine the association. Our results reveal that compared to participants in 2019, patients from the study sample of 2020 were marginally more likely to be depressed, especially female patients (male OR: 1.092, 95% CI [0.998 to 1.195], female OR: 1.066, 95% CI [1.002 to 1.134]). Moreover, using the participants from the year 2019 as a reference group, those who appeared anxious in response to the COVID-19-related questions in the survey showed more tendency to have a PHQ-9 score of 10 or more. Compared to participants from the 2019 group, those from 2020 more likely to be depressed were those with no-one to contact in case of emergency due to COVID-19 (male OR: 1.45, 95% CI [1.26 to 1.66], female OR: 1.46, 95% CI [1.33 to 1.60]), and individuals with concerns regarding economic loss (male OR: 1.18, 95% CI [1.07 to 1.30], female OR: 1.11, 95% CI [1.04 to 1.18]) and infection of a vulnerable family member at home due to COVID-19 (male OR: 1.16, 95% CI [1.05 to 1.28], female OR: 1.09, 95% CI [ 1.02 to 1.16]).

Selective detection of calcium cations on macromolecular Langmuir monolayer and Langmuir-Schaefer films.

In this study, we report the interfacial Langmuir monolayer behavior and surface morphological features of a dendronic terthiophene linked via a tetraethylene glycol moiety (3T5O3T) and its complexation with calcium cations. Surface pressure-mean molecular area (pi-A) isotherms show distinct behavior due to the secondary interaction of cations with the ionophore units. Furthermore, two Langmuir-Schaefer (LS) films with and without calcium cations exhibited significantly different surface morphological features from atomic force microscopy (AFM) imaging. Quartz crystal microbalance (QCM) measurements reveal changes in frequency and resistance enabling selective sensing of calcium cations on the LS films. Thus, well-organized 3T5O3T LS films on the solid substrates are potential candidates for highly selective chemosensing.

Facile patterning of hybrid CdSe nanoparticle films by photoinduced surface defects.

The photopatterning of CdSe quantum dots (QDs) films is facilitated by preparing defect-rich QDs on selective sites on the film. A key step is UV irradiation in the presence of a polar solvent such as methanol in situ as a "developer" which readily dissolves trioctylphosphine oxide (TOPO) but not the QDs. This results in a dramatically reduced photopatterning time and irradiation intensity requirement. The optical property changes were examined by UV-vis and fluorescence spectroscopy. Furthermore, the photo-oxidized pattern of the CdSe QD film was readily observed by fluorescence microscopy. The chemical change due to attenuation of the P═O vibration of TOPO (due to its removal) could be detected by FT-IR imaging or FT-IR chemical mapping. Thus, the protocol is a simple yet effective way of patterning PL properties of QD films at much reduced exposure time compared to previously reported methods. It may find utility for a host of cell-based film assays and PL display device applications at various resolutions.

Highly sensitive and selective "turn-on" calcium cation sensing from a dendronic terthiophene tetraethylene glycol (TEG) molecule.

A molecule consisting of a branched or dendronic terthiophene with tetraethylene glycol moiety (3T5O) was synthesized for highly sensitive and selective calcium ion detection in solution. The sulfur atoms of the terthiophene dendron moiety contribute to the metal-ligand complexation of calcium cations. The modification of the terthiophene dendrons with a hydroxyl-terminated tetraethylene glycol (TEG) group produces a twisted intramolecular charge transfer (TICT) event in which the terthiophene moiety is conformationally twisted, affecting its chromophoric and fluorophoric activity. This twisted conformation resulted in an increase in emission intensity at 320 nm, at the same time producing a blue shift in the absorption spectra. This process enabled a "turn-on" system for calcium ion detection compared to most "turn-off" systems involving a quenching route. The intensity of the emission is related to saturation of the terthiophene moiety at a concentration of 3T5O:[Ca(2+)] 1:4, of ∼1 × 10(-8) M, which indicates high sensitivity for calcium cations. No response with other cations such as Na(+), K(+), and Mg(2+) was observed, which also indicates high selectivity for the system. Conformational analysis of the 3T5O and the twisted terthiophene dendron geometry was done by semiempirical PM3 modeling. In an effort to distinguish specific interactions between monovalent and divalent cations and the 3T5O, restricted Hartree-Fock level calculations using the STO-3G basis set were also performed. The calculations correlated with the experimental results.

Amphiphilic treelike rods at interfaces: layered stems and circular aggregation.

Amphiphilic dendron-rod molecules with three hydrophilic poly(ethylene oxide) (PEO) branches attached to a hydrophobic octa-p-phenylene rod stem were investigated for their ability to form two-dimensional micellar structures on a solid surface. A treelike shape of the molecules was reported to be a major factor in the formation of nonplanar micellar structures in solution and in the bulk state (cylindrical and spherical). We observed that in these treelike amphiphilic molecules the hydrophilic terminated dendron branches assemble themselves in surface monolayers with the formation of two-dimensional layered or circular micellar structures. We suggested the formation of the planar ribbon-like structures with interdigitated layering within the loosely packed monolayers and circular, ringlike structures (2D circular aggregates) in the precollapsed state.