Publications by authors named "Ho Seong Jang"

Multicolor tunable upconversion nanoparticles (UCNPs) have garnered attention owing to their diverse applications such as displays, imaging, and security. Typically, achieving multicolor emission from UCNPs requires complicated core/multishell nanostructures comprising a core with at least five shells. Here, we propose a strategy to achieve bright and orthogonal red (R), green (G), and blue (B) upconversion (UC) luminescence without synthesizing complicated core/quintuple-shell or core/sextuple-shell nanostructures.

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Extracellular matrix (ECM) undergoes dynamic inflation that dynamically changes ligand nanospacing but has not been explored. Here we utilize ECM-mimicking photocontrolled supramolecular ligand-tunable Azo self-assembly composed of azobenzene derivatives (Azo) stacked via cation-π interactions and stabilized with RGD ligand-bearing poly(acrylic acid). Near-infrared-upconverted-ultraviolet light induces -Azo-mediated inflation that suppresses cation-π interactions, thereby inflating liganded self-assembly.

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Article Synopsis
  • Perovskite nanocrystals (NCs) are promising materials for electronic devices due to their high efficiency but face challenges with stability and surface quality.
  • A new strategy inspired by drug delivery systems involves doping Ag into CsPbBr (CPB) NCs to enhance their structural stability by targeting and repairing defects.
  • Experimental and theoretical analyses show that this approach improves the optical properties of the NCs, making them suitable for applications like white light-emitting diodes.
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Background: Various operative methods for the treatment of Morton's neuroma have been discussed, and osteotomy of the metatarsal bone has been reported recently. However, there has been no report of pedobarographic changes after metatarsal osteotomy. Pedobarographic changes of other metatarsal area after the surgery may cause transfer metatarsalgia, and thorough analysis of the pedobarographic data should be performed peri-operatively.

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In this study, we synthesized NaYF-based downshifting nanophosphors (DSNPs), and fabricated DSNP-polydimethylsiloxane (PDMS) composites. Nd ions were doped into the core and shell to increase absorbance at 800 nm. Yb ions were co-doped into the core to achieve intense near-infrared (NIR) luminescence.

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Herein, we demonstrate video-rate color three-dimensional (3D) volumetric displays using elemental-migration-assisted full-color-tunable upconversion nanoparticles (UCNPs). In the heavily doped NaErF:Tm-based core@multishell UCNPs, erbium migration was observed. By tailoring this migration through adjustment of the intermediate shell thickness between the core and the sensitizer-doped second shell, red-green orthogonal upconversion luminescence (UCL) was achieved.

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Despite the improved conversion efficiency of Cu(ZnSn)Se (CZTSe) solar cells, their roll-to-roll fabrication nonetheless leads to low performance. The selenization time and temperature are typically considered major parameters for a powder-based CZTSe film; meanwhile, the importance of the densification during the roll-to-roll process is often overlooked. The densification process is related to the porosity of the light-absorbing layer, where high porosity lowers cell performance.

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Dynamic manipulation of supramolecular self-assembled structures is achieved irreversibly or under non-physiological conditions, thereby limiting their biomedical, environmental, and catalysis applicability. In this study, microgels composed of azobenzene derivatives stacked via π-cation and π-π interactions are developed that are electrostatically stabilized with Arg-Gly-Asp (RGD)-bearing anionic polymers. Lateral swelling of RGD-bearing microgels occurs via cis-azobenzene formation mediated by near-infrared-light-upconverted ultraviolet light, which disrupts intermolecular interactions on the visible-light-absorbing upconversion-nanoparticle-coated materials.

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In this study, heavy-metal-free orange light-emitting ZnSe:Mn/ZnS doped-core/shell (d-C/S) quantum dots (QDs) were synthesized using a nucleation doping strategy. To synthesize high quality d-C/S QDs with high photoluminescence (PL) quantum yield (QY), the Mn concentration was optimized. The resulting ZnSe:Mn(5%)/ZnS d-C/S QDs showed a high PL QY of 83.

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Background: Transfer metatarsalgia is a potential complication of hallux valgus surgery. This study aimed to investigate the shortened first metatarsal length and elevation and to compare groups with and without second transfer metatarsalgia after Scarf osteotomy.

Methods: The first metatarsal length of 123 feet was measured via the Maestro's method using the metatarsal axial length and the relative second metatarsal protrusion to the first metatarsal.

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A super-boosted hybrid plasmonic upconversion (UC) architecture comprising a hierarchical plasmonic upconversion (HPU) film and a polymeric microlens array (MLA) film is proposed for efficient photodetection at a wavelength of 1550 nm. Plasmonic metasurfaces and Au core-satellite nanoassembly (CSNA) films can strongly induce a more effective plasmonic effect by providing numerous hot spots in an intense local electromagnetic field up to wavelengths exceeding 1550 nm. Hence, significant UC emission enhancement is realized via the amplified plasmonic coupling of an HPU film comprising an Au CSNA and UC nanoparticles.

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Here, excitation orthogonalized red/green/blue upconversion luminescence (UCL)-based full-color tunable rare-earth (RE) ion-doped upconversion nanophosphors (UCNPs) are reported. The LiREF-based core/sextuple-shell (C/6S) UCNPs are synthesized, and they consist of a blue-emitting core, green-emitting inner shell, and red-emitting outer shell, with inert intermediate and outermost shells. The synthesized C/6S UCNPs emit blue, green, and red light under 980, 800, and 1532 nm, respectively.

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In this study, Li-based blue- and green-emitting core@shell (C@S) upconversion nanophosphors (UCNPs) and NaGdF-based red-emitting C@S UCNPs were synthesized, and IR-808 dyes were conjugated with the C@S UCNPs to enhance upconversion (UC) luminescence. The surface of the as-synthesized C@S UCNPs, which was originally capped with oleic acid, was modified with BF to conjugate the IR-808 dye having a carboxyl functional group to the surface of the UCNPs. After the conjugation with IR-808 dyes, absorbance of the UCNPs was significantly increased.

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Ultrasmall and uniform tetrahedral-shaped YOF:Yb,Er upconversion nanophosphors (UCNs) are synthesized and sub-10 nm YOF:Yb,Er/YOF core/shell UCNs are formed via YOF:Yb,Er seed-mediated synthesis. The ultrasmall YOF:Yb,Er/YOF core/shell UCNs realize intense red emission under near infrared light (λ = 980 nm).

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Bright and single band red-emitting NaErF4:Tm,Gd-based upconversion nanophosphors (UCNPs) were successfully synthesized by the formation of a core/intermediate shell/active shell structure. The NaErF4:Tm,Gd/NaYF4:Ca,Yb/NaYF4:Nd,Yb core/shell/shell UCNPs exhibit intense red light under both 980 and 800 nm near infrared light excitations.

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In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near-infrared (NIR) light are reported. When a NaYF:Nd,Yb active-shell is formed on the 12.7 nm sized NaGdF:Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red, depending on the Ce concentration under excitation with 800 nm NIR light.

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Background: To compare the outcomes of fixation methods for osteosynthesis of a type II symptomatic accessory navicular between screw and tension band wiring.

Methods: Forty-four patients (mean age, 29.2 years; range, 13-54 years; 21 males and 23 females) who had undergone operative treatment after failed conservative treatment were chosen for the study between 2007 and 2014.

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We synthesized uniform CuInS/ZnS nanocubes by adjusting reaction parameters at the ZnS growth stage. Higher temperature and zinc concentration were shown to drive resultant crystals to have cubic morphology, which could be ascribed to the facet-dependent ligand dynamics on the crystal surface and concomitantly preferred directions of crystal growth. It was found that these nanocubes exhibit sensitive responses, as of photoluminescence quenching, toward hydrogen peroxide, compared to pyramid-shaped nanocrystals.

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Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F:Yb,Er and Li(Gd,Y)F:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF shell.

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To realize blue emission-capable non-Cd I-III-VI quantum dots (QDs), we explore the synthesis of ternary Cu-Ga-S (CGS) QDs and subsequent quaternary Zn-Cu-Ga-S (ZCGS) via Zn alloying into a CGS host. The resulting ZCGS/ZnS core/shell QDs possess not only Zn content-dependent tunable emissions in the azure-to-blue range but also exceptional quantum yields of 78-83%.

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Colloidal quantum dots (QDs) are attractive candidates for future lighting technology. However, in contrast to display applications, the realization of balanced white lighting devices remains conceptually challenging. Here, we demonstrate two-component white light-emitting QD-LEDs with high color rendering indices (CRI) up to 78.

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Purpose: Docetaxel-based chemotherapy (DTX) improves overall survival (OS) of men with metastatic castration-resistant prostate cancer (mCRPC). Considering the potential existence of androgen receptors that remain active at this stage, we aimed to assess the impact of the combined use of androgen deprivation therapy (ADT) with DTX for mCRPC.

Materials And Methods: We performed a single-institutional retrospective analysis of patients with mCRPC who received either DTX alone (DTX group, n=21) or concurrent DTX and ADT (DTX+ADT group, n=26) between August 2006 and February 2014.

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Three-order enhanced upconversion luminescence from upconversion nanoparticles is suggested by way of a promising platform utilizing a disordered array of plasmonic metal nanoparticles. Its application toward highly sensitive NIR photodetectors is discussed.

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Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors-Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4-and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce(3+) to Tb(3+) under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors.

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