Publications by authors named "Jong-Ik Lee"

Electrochemiluminescence (ECL) holds significant promise for the development of cost-effective light-emitting devices because of its simple structure. However, conventional ECL devices (ECLDs) have a major limitation of short operational lifetimes, rendering them impractical for real-world applications. Typically, the luminescence of these devices lasts no longer than a few minutes during operation.

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Neural interfaces play a major role in modulating neural signals for therapeutic purposes. To meet the demand of conformable neural interfaces for developing bioelectronic medicine, recent studies have focused on the performance of electrical neurostimulators employing soft conductors such as conducting polymers and electronic or ionic conductive hydrogels. However, faradaic charge injection at the interface of the electrode and nerve tissue causes irreversible gas evolution, oxidation of electrodes, and reduction of biological ions, thus causing undesired tissue damage and electrode degradation.

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The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples of Ryugu were retrieved by the Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in Ryugu samples and found that they are dominated by presolar and primordial components, incorporated during Solar System formation.

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Article Synopsis
  • The Hayabusa2 spacecraft successfully returned to Earth from the asteroid 162173 Ryugu on December 6, 2020, and samples were recovered the next day.
  • The extracted gas from the sample container contained helium and neon and had unique extraterrestrial ratios, indicating some contamination from Earth’s atmosphere.
  • This mission marks the first successful return of gas species from a near-Earth asteroid, and discussions are held regarding the fragmentation of Ryugu grains in relation to the gas composition.
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Electrochemiluminescence (ECL) has an inherently low background and enables precise chemical reactions through electrical control. Here, we report an advanced ECL system, termed ECLipse (ECL in paired signal electrode). We physically separated ECL generation from target detection: These two processes were carried out in isolated chambers and coupled through an electrode.

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Smart contact lenses have the potential to serve as noninvasive healthcare devices or virtual displays. However, their implementation is limited by the lack of suitable power sources for microelectronic devices. This Article demonstrates smart contact lenses with fully embedded glucose fuel cells that are safe, flexible, and durable against deformations.

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We report the complete and circularized genome sequences of Brevibacterium frigoritolerans Ant232, generated using a combination of Illumina and PacBio platforms. The high-quality complete genome consists of a circular 5,586,945-bp chromosome and a 305,498-bp plasmid, with G+C contents of 40.66% and 36.

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  • Researchers studied the performance of single-structured light-emitting electrochemical cells (LECs) using a Ru(bpy)(PF) polymer composite for the emission layer, focusing on thickness and heat treatment effects.
  • They found that a thickness of 150 nm offered the best balance, with improved optical properties and low surface roughness, while thicknesses below 120-150 nm or above 150 nm led to decreased performance and stability issues.
  • Heat treatment at 100 °C enhanced the surface properties, resulting in stable operation and achieving a maximum luminance of 3532 cd/m and an external quantum efficiency (EQE) of 1.14% at the optimal 150 nm thickness.
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Following early research efforts devoted to achieving excellent sensitivity of electronic skins, recent design schemes for these devices have focused on strategies for transduction of spatially resolved sensing data into straightforward user-adaptive visual signals. Here, a material platform capable of transducing mechanical stimuli into visual readout is presented. The material layer comprises a mixture of an ionic transition metal complex luminophore and an ionic liquid (capable of producing electrochemiluminescence (ECL)) within a thermoplastic polyurethane matrix.

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The hole density of individual copper sulfide nanocrystals (CuS NCs) is determined from the stoichiometric mismatch () between copper and sulfide atoms. Consequently, the electronic properties of the material vary over a range of . To exploit CuS NCs in devices, assemblies of NCs are typically required.

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Article Synopsis
  • Humans use a combination of stimulus-response systems and conscious responses to adapt to changes in their environment and tackle external stimuli.
  • This paper introduces an artificial version of this system, which mimics human responses through components like visual receptors, synapses, and neuron circuits.
  • The research highlights how this artificial system learns from repeated stimuli to improve response times, potentially paving the way for advancements in AI-based organs for individuals with neurological disorders.
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We report the first high-resolution record of arsenic (As) observed in Greenland snow and ice for the periods 1711-1970 and 2003-2009 AD. The results show well-defined large-scale atmospheric pollution by this toxic element in the northern hemisphere, beginning as early as the 18th century. The most striking feature is an abrupt, unprecedented enrichment factor (EF) peak in the late 1890s, with an ∼30-fold increase in the mean value above the Holocene natural level.

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Rationale: The three oxygen isotopes in terrestrial/extraterrestrial silicates can provide geochemical and cosmochemical information about their origin and secondary processes that result from isotopic exchange. A laser fluorination technique has been widely used to extract oxygen from silicates for δ O and δ O measurements by isotope ratio mass spectrometry. Continued improvement of the techniques is still important for high-precision measurement of oxygen-isotopic ratios.

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  • Electrochemiluminescence (ECL) is a process where light is emitted through electrochemical reactions involving luminophores, and this concept is utilized in a new type of device called an ECL device (ECLD).
  • A model was created to understand how the transport and reaction rates of these luminophores affect the brightness of ECLDs when driven by alternating current voltage.
  • The study reveals that while increasing operational frequency (f) initially boosts brightness by enhancing reactions, at very high frequencies the effectiveness decreases due to slower reactions at the electrodes.
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Although rocks are habitable places for microbes in extreme environments, microbial diversity in these lithic environments is still poorly understood. The diversity and abundance of rock-inhabiting microbial communities in different types of rock in Svalbard, Norwegian High Arctic were examined using NGS sequencing of bacterial 16S rRNA genes and fungal 28S rRNA genes. Compositions of both bacterial and fungal communities varied across different rock types: sandstone, limestone, basalt, granite and travertine.

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Lead halide perovskites with nanoscale geometries have received recent attention due to the defect-tolerant high photoluminescence quantum yield at tunable emission wavelengths and the possibility of room-temperature synthesis that does not compromise the physical properties of the materials. These characteristics offer opportunities to advance displays that cover the widest perceivable color. However, lead toxicity obstructs the commercialization of this technology.

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The aim of this study was to compare the short-term audiologic results of the ossiculoplasty using partial or total ossicular replacement prostheses (PORP or TORP) made of hydroxyapatite (HA) and titanium (Ti). Fifty-two consecutive patients who underwent ossiculoplasty due to chronic otitis media with or without cholesteatoma were enrolled. Patients were assessed at 6 months postoperatively to establish short-term audiologic results.

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Rationale: Cryogenic trapping using molecular sieves is commonly used to collect O2 extracted from silicates for (17)O/(16)O and (18)O/(16)O analyses. However, gases which interfere with (17)O/(16)O analysis, notably NF3, are also trapped and their removal is essential for accurate direct measurement of the (17)O/(16)O ratio. It is also necessary to identify and quantify any isotopic fractionation associated with the use of cryogenic trapping using molecular sieves.

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  • This study investigates the occurrence of second primary cancers (SPCs) in patients with salivary gland cancers (SGCs) compared to new cancers in healthy individuals.
  • It includes a retrospective analysis of 184 SGC patients and 200 healthy controls, focusing on risk factors and cumulative incidence over time.
  • Results show similar SPC rates in SGC patients and the control group, with no significant predictors identified, indicating further research with larger samples is needed.
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The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made of the impact event and the meteoroid that caused it. Here, we document the account of what happened, as understood now, using comprehensive data obtained from astronomy, planetary science, geophysics, meteorology, meteoritics, and cosmochemistry and from social science surveys.

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