Depressive disorder is a common mental illness and remains a major cause of morbidity worldwide. The present study, a cross-sectional, nationwide, population-based survey assessed the prevalence of depression in the general population of Korea through a random sampling of the non-institutionalized population for the Korea National Health and Nutrition Examination Survey (KNHANES) VI. The Patient Health Questionnaire (PHQ)-9 was first introduced into the KNHANES to detect depression. The point prevalence of depression (PHQ score of 10 or higher) was 6.7% (95% confidence interval [CI], 5.7–7.6) in 4,949 subjects. Based on the analysis using the diagnostic algorithm of the PHQ-9, the prevalence of major depressive disorder was 2.7% (95% CI, 2.2–3.3). Multiple logistic regression analysis, after adjusting the sociodemographic variables, also showed that the factors associated with depression were perceived stress and health status. This study reported for the first time that the point prevalence of depression screened using the PHQ-9 in this nationwide survey of the Korean population was similar to that of the western countries. As the KNHANES to detect depression is conducted biennially, further studies on the accumulated data are expected in the future.

The effects of nonionic surfactant additive, Triton X-100, on the properties of PEDOT:PSS thin films has been investigated. The detailed mechanism for the well-known conductivity enhancement upon the addition of high boiling point nonionic surfactant has been elucidated based on various characterization results. The surfactant additive has been found to enhance the π–π stacking of PEDOT segment, leading to enhanced electrical conductivity. In addition, the added surfactant has facilitated the removal of insulating PSS during the methanol spin washing, which contributes to further enhancement in electrical conductivity. Interestingly, the remaining surfactant in the dried PEDOT:PSS thin films plays the role of plasticizer. Upon aging of the films under room ambient (RH ∼ 30%), the conductivity of the film has been gradually increased until the humidity effect comes in. As a plasticizer, the surfactant has been found to enhance lamella stacking during the aging. Also, the mechanical modulus of the films has been characterized by the buckling method, which proves the softening effect of residual surfactant for PEDOT:PSS films. On the other hand, the reinforcing filler effect of PEDOT crystallites has been found to be negligible compared to plasticizer effect.

Highly efficient organic–inorganic hybrid solar cells of Si‐poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) have been demonstrated by simultaneous structural, electrical, and interfacial engineering with low processing temperature. Si substrate has been sculpted into hierarchical structure to reduce light reflection loss and increase interfacial junction area at the same time. Regarding the electrical optimization, highly conductive organic PEDOT:PSS layer has been formulated with low sheet resistance. It is argued that the sheet resistance, rather than conductivity, is the primary parameter for the high efficiency hybrid cells, which leads to the optimization of thickness, i.e., thick enough to have low sheet resistance but transparent enough to pass the incident sunlight. Finally, siloxane oligomers have been inserted into top/bottom interfaces by contact‐printing at room ambient, which suppresses carrier recombination at interfaces and reduces contact resistance at bottom electrode. Contrary to high‐temperature doping (for the formation of front surface or back surface fields), wet solution processes or vacuum‐based deposition, the contact‐printing can be done at room ambient to reduce carrier recombination at the interfaces. The high efficiency obtained with low processing temperature can make this type of cells be a possible candidate for post‐Si photovoltaics.

Room-temperature welding and sintering of metal nanostructures, nanoparticles and nanowires, by capillary condensation of chemical vapors have successfully been demonstrated. Nanoscale gaps or capillaries that are abundant in layers of metal nanostructures have been found to be the preferred sites for the condensation of chemically oxidizing vapor, H2O2 in this work. The partial dissolution and resolidification at such nanogaps completes the welding/sintering of metal nanostructures within ∼10 min at room-temperature, while other parts of nanostructures remain almost intact due to negligible amount of condensation on there. The welded networks of Ag nanowires have shown much improved performances, such as high electrical conductivity, mechanical flexibility, optical transparency, and chemical stability. Chemically sintered layers of metal nanoparticles, such as Ag, Cu, Fe, Ni, and Co, have also shown orders of magnitude increase in electrical conductivity and improved environmental stability, compared to nontreated ones. Pertinent mechanisms involved in the chemical welding/sintering process have been discussed. Room-temperature welding and sintering of metal nanostructures demonstrated here may find widespread application in diverse fields, such as displays, deformable electronics, wearable heaters, and so forth.

Various automated chemiluminescence immunoassay (CLIA) analyzers for the detection of antibodies to hepatitis C virus (HCV) are now commercially available in clinical laboratories and are replacing conventional enzyme immunoassays. We investigated the performance of four anti-HCV CLIAs (the Architect Anti-HCV assay on the Architect i2000 system, the Vitros Anti-HCV assay on the Vitros ECiQ Immunodiagnostic System, the Access HCV Ab PLUS assay on the UniCel DxI 800 analyzer, and the newly developed Elecsys Anti-HCV assay on the Cobas e 411 analyzer). The total percent coefficient of variation values of imprecision were 3.5 to 5.7% with positive control materials and 7.2 to 10.2% with negative control materials. The agreement between the results of the Elecsys, Architect, Vitros, and Access CLIAs ranged from 94.5 to 98.1%. The clinical sensitivity of all CLIAs was 100%. Each CLIA showed excellent reproducibility and clinical sensitivity. The Elecsys, Architect, Vitros, and Access CLIAs showed clinical specificities of 98.2, 98.8, 96.5, and 98.2%.Hepatitis C virus (HCV), first identified in 1989, is an enveloped positive-strand RNA virus classified in the Hepacivirus genus in the family Flaviviridae (6). The HCV genome is about 9.5 kb in length and encodes 3,011-to 3,033-amino-acid polypeptides in structural and nonstructural regions (20). The structural region contains the core protein and two envelope proteins (E1 and E2), and nonstructural proteins have been assigned protease (NS2, NS3, and NS4A), helicase (NS3), and RNA-dependent RNA polymerase (NS5B) (21) functions.The first commercially available anti-HCV enzyme immunoassay (EIA) used a single HCV recombinant antigen derived from the nonstructural NS4 protein designated c100-3 (19). The sensitivity of this first-generation EIA was low for a highprevalence population (approximately 80%) and showed a high false-positive rate (up to 70%) in a low-prevalence blood donor group (13). Therefore, a second-generation EIA was developed and approved for use by the Food and Drug Administration (FDA) in 1992 (3). The second-generation EIA, which contained additional HCV antigens from the core (c22-3) and NS3 (c33c) proteins, showed increased sensitivity and specificity and shortened the average seroconversion period from 16 to 10 weeks (1, 3, 13, 18). The third-generation EIA, which added a fourth antigen (NS5), showed significantly improved performance, particularly for high-risk patients (2, 8). However, a residual risk still exists due to the seroconversion period of approximately 56 days, and high false-positive rates were not resolved (12). The Centers for Disease Control and Prevention (CDC) recommended that an anti-HCV screening test positive result be verified by a more specific supplemental assay such as recombinant immunoblot or nucleic acid test (5). To facilitate the use of the supplemental assay, the revised guideline included an option for reflex supplemental testing based on signal-to-cutoff (s/co) ratios (4).Today, automated chemiluminescence immunoassay (...