Iron Oxide Nanoparticles Modified with Galloylated DNA for Magnetically Enhanced DNA-Directed Assembly.

A straightforward, one-step method is presented for DNA functionalization of iron oxide nanoparticles (IONP) using galloylated DNA through multidentate metal-phenol interactions. The DNA-modified IONPs exhibit excellent stability under diverse buffer conditions and display intriguing DNA binding properties, influenced by the superparamagnetic property of IONPs. The DNA denaturation behavior can be categorized into two regimes: the magnetic-dominant regime and the DNA-dominant regime.

Transmission Dynamics and Parameters for Pertussis during School-Based Outbreak, South Korea, 2024.

We estimated the serial interval and superspreading potential to quantify pertussis transmission dynamics in a 2024 school-based outbreak of a population in South Korea that had received a series of pertussis vaccinations. We analyzed 48 cases of pertussis and reconstructed 36 transmission pairs. We then used maximum-likelihood estimation to assess serial interval and offspring distribution from transmission pair data.

COVID-19 infection among people with disabilities in 2021 prior to the Omicron-dominant period in the Republic of Korea: a cross-sectional study.

Background: This study investigated the characteristics of coronavirus disease 2019 (COVID-19) among individuals with disabilities on a nationwide scale in the Republic of Korea, as limited research has examined this population.

Methods: Between January 1 and November 30, 2021, a total of 5,687 confirmed COVID-19 cases among individuals with disabilities were reported through the Korea Disease Control and Prevention Agency's COVID-19 web reporting system. Follow-up continued until December 24, and demographic, epidemiological, and clinical characteristics were analyzed.

Application of the Time Derivative (TD) Method for Early Alert of Influenza Epidemics.

Background: In order to minimize the spread of seasonal influenza epidemic to communities worldwide, the Korea Disease Control and Prevention Agency has issued an influenza epidemic alert using the influenza epidemic threshold formula based on the results of the influenza-like illness (ILI) rate. However, unusual changes have occurred in the pattern of respiratory infectious diseases, including seasonal influenza, after the coronavirus disease 2019 (COVID-19) pandemic. As a result, the importance of detecting the onset of an epidemic earlier than the existing epidemic alert system is increasing.

Free-standing two-dimensional sheets of polymer-linked nanoparticles.

Here, we report a simple and general approach to fabricate free-standing two-dimensional (2D) sheets of nanoparticles by the simultaneous self-assembly of hydrophobic nanoparticles and hydrophilic polymers at the liquid-liquid interface. The nanoparticle-polymer interaction at the interface generates well-defined 2D sheets of densely packed nanoparticles with a lateral dimension of tens of micrometers. The nanosheets transferred in water are stable over months without any additional cross-linking step.

Conjugated Block Copolymers for Functional Nanostructures.

Conjugated polymers have been actively studied as an alternative to inorganic semiconductors for their unique optical and electrical properties and low-cost solution processability. However, typical conjugated polymer films contain numerous defects that negatively affect their transport properties, which remains a major issue despite much effort to develop ways to improve the molecular packing structure. In principle, conjugated block copolymers (BCPs) composed of a rod-type conjugated polymer and a coil-type insulating polymer can assemble into various types of ordered nanostructures based on the microphase segregation of two polymer blocks.

Magnetic Field-Induced Self-Assembly of Conjugated Block Copolymers and Nanoparticles at the Air-Water Interface.

Here, we report the magnetic field-induced self-assembly of a conjugated block copolymer, poly(3-hexylthiopene)--poly(ethylene glycol) (P3HT--PEG), and iron oxide nanoparticles (IONPs) at the air-water interface. Binary self-assembly of P3HT--PEG and IONPs at the interface results in nanoparticle-embedded P3HT--PEG nanowire arrays with a micrometer-scale domain size. Under the magnetic field, the field-induced magnetic interaction significantly improves the degree of order, generating long-range ordered, direction-controlled nanoarrays of P3HT--PEG and IONPs, where IONPs are aligned in the direction of the magnetic field over a sub-millimeter scale.

Real-space imaging of nanoparticle transport and interaction dynamics by graphene liquid cell TEM.

Thermal motion of colloidal nanoparticles and their cohesive interactions are of fundamental importance in nanoscience but are difficult to access quantitatively, primarily due to the lack of the appropriate analytical tools to investigate the dynamics of individual particles at nanoscales. Here, we directly monitor the stochastic thermal motion and coalescence dynamics of gold nanoparticles smaller than 5 nm, using graphene liquid cell (GLC) transmission electron microscopy (TEM). We also present a novel model of nanoparticle dynamics, providing a unified, quantitative explanation of our experimental observations.

Temperature-Responsive On-Off Control over Water Evaporation Achieved via Sweat-Gland-Mimetic Composites.

Responsive cooling materials that mimic sweat glands have gained popularity because they are efficient and do not require artificial energy sources. Temperature-responsive hydrogels sweat above their volume transition temperature through the release of water and exhibit excellent cooling ability. However, thus far, practical applications have not been possible because the water in these materials cannot be preserved in cool environments.

Correlating 3D Surface Atomic Structure and Catalytic Activities of Pt Nanocrystals.

Active sites and catalytic activity of heterogeneous catalysts is determined by their surface atomic structures. However, probing the surface structure at an atomic resolution is difficult, especially for solution ensembles of catalytic nanocrystals, which consist of heterogeneous particles with irregular shapes and surfaces. Here, we constructed 3D maps of the coordination number (CN) and generalized CN () for individual surface atoms of sub-3 nm Pt nanocrystals.

Nanoparticle-Induced Self-Assembly of Block Copolymers into Nanoporous Films at the Air-Water Interface.

Herein, we report the cooperative self-assembly of nanoparticles and block copolymers at the air-water interface, which can generate highly uniform and readily transferable composite films with tunable nanoscale architecture and functionalities. Interestingly, the incorporation of nanoparticles significantly affects the self-assembly of block copolymers at the interface. The nanoparticle-induced morphology change occurs through distinct mechanisms depending on the volume fraction of the hydrophobic block.

Stretchable Lithium-Ion Battery Based on Re-entrant Micro-honeycomb Electrodes and Cross-Linked Gel Electrolyte.

Stretchable energy storage devices are of great interest because of their potential applications in body-friendly, skin-like, wearable devices. However, stretchable batteries are very challenging to fabricate. The electrodes must have a degree of stretchability because the active materials occupy most of the volume, and the separator and packaging should also be stretchable.

Long-Range Order Self-Assembly of Conjugated Block Copolymers at Inclined Air-Liquid Interfaces.

Here, we report that long-range order, direction-controlled, ultrathin conjugated polymer films can be formed by the self-assembly of conjugated block copolymers (i.e., poly(3-hexylthiophene)--poly(ethylene glycol)) at inclined air-water interfaces.

Binary Self-Assembly of Conjugated Block Copolymers and Quantum Dots at the Air-Liquid Interface into Ordered Functional Nanoarrays.

Controlling the nanoscale morphology of conducting polymer/nanoparticle hybrid films is a highly desired but challenging task. Here, we report that such functional hybrid films with unprecedented structural order can be formed through the self-assembly of conjugated block copolymers and CdSe quantum dots at the air-water interface. The one-step assembly of quantum dots and block copolymers composed of polythiophene and polyethylene glycol (P3HT--PEG) at the fluidic interface generated a highly ordered assembly structure of P3HT nanowires and one-dimensional quantum dot arrays.

2D reentrant auxetic structures of graphene/CNT networks for omnidirectionally stretchable supercapacitors.

Stretchable energy storage systems are essential for the realization of implantable and epidermal electronics. However, high-performance stretchable supercapacitors have received less attention because currently available processing techniques and material structures are too limited to overcome the trade-off relationship among electrical conductivity, ion-accessible surface area, and stretchability of electrodes. Herein, we introduce novel 2D reentrant cellular structures of porous graphene/CNT networks for omnidirectionally stretchable supercapacitor electrodes.