552 results on '"Kim, Dongho"'
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2. The gE/gI complex is necessary for kinesin-1 recruitment during alphaherpesvirus egress from neurons.
- Author
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Diwaker D, Kim D, Cordova-Martinez D, Pujari N, Jordan BA, Smith GA, and Wilson DW
- Abstract
Following reactivation of a latent alphaherpesvirus infection, viral particles are assembled in neuronal cell bodies, trafficked anterogradely within axons to nerve termini, and spread to adjacent epithelial cells. The virally encoded membrane proteins US9p and the glycoprotein heterodimer gE/gI of pseudorabies virus (PRV) and herpes simplex virus type 1 (HSV-1) play critical roles in anterograde spread, likely as a tripartite gE/gI-US9p complex. Two kinesin motors, kinesin-1 and kinesin-3, are implicated in the egress of these viruses, but how gE/gI-US9p coordinates their activities is poorly understood. Here, we report that PRV, in addition to associating with the kinesin-3 motor KIF1A, recruits the neuronal kinesin-1 isoforms KIF5A and KIF5C, but not the broadly expressed isoform KIF5B, during egress from differentiated CAD neurons. Similarly, in the axons of dorsal root ganglia (DRG)-derived sensory neurons, PRV colocalized with KIF5C but not KIF5B. In differentiated CAD cells, the association of KIF1A with egressing PRV was dependent upon US9p, whereas the recruitment of KIF5 isoforms required gE/gI. Consistent with these findings, the number of PRV particles trafficking within CAD neurites and the axons of DRG neurons increased when kinesin-1 motor activity was upregulated by hyperacetylating microtubules using trichostatin A (TSA) or tubacin, and this enhanced trafficking depended upon the presence of gE/gI. We propose that, following its recruitment by US9p, KIF1A delivers PRV particles to a location where KIF5 motors are subsequently added by a gE/gI-dependent mechanism. KIF5A/C isoforms then serve to traffic viral particles along axons, resulting in characteristic recrudescent infection., Importance: Alphaherpesviruses include important human and veterinary pathogens that share a unique propensity to establish life-long latent infections in the peripheral nervous system. Upon reactivation, these viruses navigate back to body surfaces and transmit to new hosts. In this study, we demonstrate that the virus gE/gI-US9p membrane complex routes virus particles down this complex neuronal egress pathway by coordinating their association with multiple kinesin microtubule motors.
- Published
- 2024
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3. Clinical Features of Patients Treated With Hair Transplants in Female Pattern Hair Loss.
- Author
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Yun D, Kim D, Juhyun C, Yeom K, Kim MH, Choi MS, Park G, Park JH, Ahn J, Jung J, Cho H, Hwang S, and Park BC
- Abstract
Background: Hair transplantation (HT) has been reported to be effective for the treatment of female-pattern hair loss (FPHL). Few studies have investigated HT in FPHL., Objective: To evaluate the clinical features of FPHL treated with HT and analyze the real-world results of HT., Methods: We conducted a retrospective chart review of 195 FPHL patients who underwent hair transplants. The patients' demographics, clinical features, and clinical courses of HT were recorded., Results: The mean (±SD) age of patients was 49.1±11.9 years. Analysis of the severity of hair loss showed that 31.8%, 49.7%, and 18.5% of patients had F1, F2, and F3 types of hair loss (according to the BASP Classification); 88.2% of patients had more than 75% satisfaction with HT. The satisfaction level was significantly higher in the group that had the highest number of hairs implanted. Complications such as pain, facial edema, folliculitis, scar, paresthesia, telogen effluvium were found., Conclusion: This study could provide substantial information of HT in FPHL. Clinicians could deliver more sufficient counsel to FPHL patients about HT., Competing Interests: The authors have nothing to disclose., (© 2024 The Korean Dermatological Association and The Korean Society for Investigative Dermatology.)
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- 2024
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4. Comparative efficiency of the SWAT model and a deep learning model in estimating nitrate loads at the Tuckahoe creek watershed, Maryland.
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Lee J, Kim D, Hong S, Yun D, Kwon D, Hill RL, Gao F, Zhang X, Cho KH, Lee S, and Pachepsky Y
- Abstract
Modeling nitrate fate and transport in water sources is an essential component of predictive water quality management. Both mechanistic and data-driven models are currently in use. Mechanistic models, such as SWAT, simulate daily nitrate loads based on the results of simulating water flow. Data-driven models allow one to simulate nitrate loads and water flow independently. Performance of SWAT and deep learning model was evaluated in cases when deep learning model is used in (a) independent simulations of flow series and nitrate concentration series, and (b) in both flow rate and concentration simulations to obtain nitrate load values. The data were collected at the Tuckahoe Creek watershed in Maryland, United States. The data-driven deep learning model was built using long-short-term-memory (LSTM) and three-dimensional convolutional networks (3D Convolutional Networks) to simulate flow rate and nitrate concentration using weather data and imagery to derive leaf area index according to land use. Models were calibrated with data over training period 2014-2017 and validated with data over testing period. SWAT Nash-Sutcliffe efficiency (NSE) was 0.31 and 0.40 for flow rate and -0.26 and -0.18 for the nitrate load rate over training and testing periods, respectively. Three data-driven modeling scenarios were implemented: (1) using the observed flow rate and simulated nitrate concentration, (2) using the simulated flow rate and observed nitrate concentration, and (3) using the simulated flow rate and nitrate concentration. The deep learning model performed better than SWAT in all three scenarios with NSE from 0.49 to 0.58 for training and from 0.28 to 0.80 for testing periods with scenario 1 showing the best results. The difference in performance was most pronounced in fall and winter seasons. The deep learning modeling can be an efficient alternative to mechanistic watershed-scale water quality models provided the regular high-frequency data collection is implemented., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier B.V.)
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- 2024
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5. Temperature Controlled Decay and Pendulum Dynamics of Green Fluorescent Protein (GFP) Chromophore.
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Park W, Oh J, Kim J, Lee S, Kim JH, Huix-Rotllant M, Kim D, and Choi CH
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- Spectrometry, Fluorescence, Green Fluorescent Proteins chemistry, Molecular Dynamics Simulation, Temperature
- Abstract
The excited-state dynamics of the GFP chromophore, HBDI
- (anionic p -hydroxybenzylidene-2,3-dimethylimidazolinone), were investigated through a combination of theoretical nonadiabatic molecular dynamics (NAMD) simulations and femtosecond transient absorption spectroscopy (fs-TA). The NAMD simulations revealed that the primary dynamics in excited states involve the formation of a P-twisted intermediate (S1 min , P ), which undergoes pendulum-like oscillations with respect to ϕ = 90°. This motion serves as a reservoir for the excited-state population and the primary source of fluorescence. Rather than a direct channel from the major S1 min , P , a coordinated pathway of S1 min , P → S1 min → S1 min , I → S0 is responsible for the decay to the ground state, emphasizing the importance of planar intermediate (S1 min ) formation. The experimental fs-TA spectra confirmed these dynamics, revealing three distinct time scales (340-470 fs, 1.4 ps, and 8.3 ps), corresponding to the formation of S1 min , P and its decay governed by the coordinated pathway. At low temperatures, the coordinated decay pathway is suppressed, leading to prolonged fluorescence lifetimes, consistent with low-temperature experimental results. This study presents a new model for the excited-state dynamics of GFP chromophore, suggesting that pendulum motion and the coordinated decay pathway play a crucial role in regulating fluorescence intensity.- Published
- 2024
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6. Inner-Bond-Cleavage Approach to Figure-Eight Macrocycles from Planar Aromatic Hydrocarbons.
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Yoshina R, Hirano J, Nishimoto E, Sakamoto Y, Tajima K, Minabe S, Uyanik M, Ishihara K, Ikai T, Yashima E, Omine T, Ishiwari F, Saeki A, Kim J, Oh J, Kim D, Liu G, Yasuda T, Shinokubo H, and Fukui N
- Abstract
Figure-eight-shaped nonplanar π-systems adopt distinctive chiral D
2 -symmetric structures, which are ideal for realizing efficient circularly polarized luminescence (CPL). However, the short-step and enantioselective synthesis of figure-eight π-systems represents a considerable challenge for the conventional bottom-up synthetic strategy. Herein, we report that the oxidative cleavage of the internal double bond of a commercially available polycyclic aromatic hydrocarbon, i.e., dibenzo[ g , p ]chrysene (DBC), catalytically affords a figure-eight electron-accepting macrocycle, i.e., cyclobisbiphenylenecarbonyl (CBBC), with high scalability (up to 3.3 g) and excellent enantioselectivity (94% ee). This inner-bond-cleavage approach also applies to larger PAHs, affording highly distorted molecular frameworks that comprise two figure-eight subunits. Furthermore, we demonstrate that the peripheral functionalization of CBBC with carbazole afforded donor-acceptor-type emitter, which shows thermally activated delayed fluorescence and emits CPL with a g value of 1.0 × 10-2 . This g value is ten times higher than those of previously reported chiral TADF-active emitters for circularly polarized organic light-emitting diodes. These results demonstrate that oxidative inner-bond cleavage is a powerful synthetic strategy for creating innovative materials that incorporate molecules with figure-eight structures.- Published
- 2024
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7. Sculpting the Electronic Nano-Terrain on a Perovskite Film for Efficient Charge Transport.
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Kim T, Chun DH, Roe DG, Kim W, Lee J, Kim J, Choi D, Choi DG, Cho JH, Park JH, and Kim D
- Abstract
Nanopatterned halide perovskites have emerged to improve the performance of optoelectronic devices by controlling the crystallographic and optical properties via morphological modification. However, the correlation between the photophysical property and morphology transformation in nanopatterned perovskite films remains elusive, which hinders the rational design of nanopatterned halide perovskites for optoelectronic devices. In this study, we employed nanoimprinting lithography on a perovskite film to exert a precise control over grain growth and manipulate electronic structures at the level of individual grains. Surface-selective fluorescence lifetime imaging microscopy (FLIM) analyzes the spatiotemporally disentangled geometrical variations in carrier recombination rate and band structure modulation according to different pattern morphologies. Consequently, the stereoscopic mechanism of confined grain growth was unveiled, highlighting the quantitative grain size-based parameters that are crucial for nanoscale material engineering. Notably, the pattern-induced reduction of effective charge mass enabled exclusive control over the subdiffusive carrier transport dynamics on perovskite surfaces, ultimately realizing the surface-selective perovskite photodetectors. The implications of this study are expected to provide valuable guidelines, inspiring innovative design protocols for advancing the next-generation optoelectronic technologies.
- Published
- 2024
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8. Efficient Electron Transfer Driven by Excited-State Structural Relaxation in Corrole-Perylenedimiide Dyad.
- Author
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Kusy D, Song H, Rząca A, Banasiewicz M, Barboza CA, Kim D, and Gryko DT
- Abstract
A sterically encumbered trans -A
2 B-corrole possessing a perylenediimide (PDI) scaffold in close proximity to the macrocycle has been synthesized via a straightforward route. Electronic communication as probed via steady-state absorption or cyclic voltammetry is weak in the ground state, in spite of the corrole ring and PDI being bridged by an o -phenylene unit. The TDDFT excited-state geometry optimization suggests after excitation the interchromophoric distance is markedly reduced, thus enhancing the through-space electronic coupling between the corrole and the PDI. This is corroborated by the strong deviation of the emission spectrum originating from both PDI and corrole in the dyad. Selective excitation of both donor and acceptor units triggers efficient sub-picosecond electron transfer and hole transfer, respectively, followed by fast charge recombination. In comparison to previously studied corrole-PDI dyads, both charge separation and charge recombination occur faster, because of the structural relaxation in the excited state.- Published
- 2024
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9. Spatial calibration and uncertainty reduction of the SWAT model using multiple remotely sensed data.
- Author
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Lee S, Kim D, McCarty GW, Anderson M, Gao F, Lei F, Moglen GE, Zhang X, Yen H, Qi J, Crow W, Yeo IY, and Sun L
- Abstract
Remotely sensed products are often used in watershed modeling as additional constraints to improve model predictions and reduce model uncertainty. Remotely sensed products also enabled the spatial evaluation of model simulations due to their spatial and temporal coverage. However, their usability is not extensively explored in various regions. This study evaluates the effectiveness of incorporating remotely sensed evapotranspiration (RS-ET) and leaf area index (RS-LAI) products to enhance watershed modeling predictions. The objectives include reducing parameter uncertainty at the watershed scale and refining the model's capability to predict the spatial distribution of ET and LAI at sub-watershed scale. Using the Soil and Water Assessment Tool (SWAT) model, a systematic calibration procedure was applied. Initially, solely streamflow data was employed as a constraint, gradually incorporating RS-ET and RS-LAI thereafter. The results showed that while 14 parameter sets exhibit satisfactory performance for streamflow and RS-ET, this number diminishes to six with the inclusion of RS-LAI as an additional constraint. Furthermore, among these six sets, only three effectively captured the spatial patterns of ET and LAI at the sub-watershed level. Our findings showed that leveraging multiple remotely sensed products has the potential to diminish parameter uncertainty and increase the credibility of intra-watershed process simulations. These results contributed to broadening the applicability of remotely sensed products in watershed modeling, enhancing their usefulness in this field., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)
- Published
- 2024
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10. The HSV-1 pUL37 protein promotes cell invasion by regulating the kinesin-1 motor.
- Author
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Kim D, Cianfrocco MA, Verhey KJ, and Smith GA
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- Humans, Animals, Axonal Transport physiology, Chlorocebus aethiops, Centrosome metabolism, Neurons metabolism, Neurons virology, Vero Cells, Cell Nucleus metabolism, Cell Nucleus virology, Kinesins metabolism, Herpesvirus 1, Human physiology, Herpesvirus 1, Human metabolism, Viral Structural Proteins
- Abstract
Neurotropic alphaherpesviruses, including herpes simplex virus type 1 (HSV-1), recruit microtubule motor proteins to invade cells. The incoming viral particle traffics to nuclei in a two-step process. First, the particle uses the dynein-dynactin motor to sustain transport to the centrosome. In neurons, this step is responsible for long-distance retrograde axonal transport and is an important component of the neuroinvasive property shared by these viruses. Second, a kinesin-dependent mechanism redirects the particle from the centrosome to the nucleus. We have reported that the kinesin motor used during the second step of invasion is assimilated into nascent virions during the previous round of infection. Here, we report that the HSV-1 pUL37 tegument protein suppresses the assimilated kinesin-1 motor during retrograde axonal transport. Region 2 (R2) of pUL37 was required for suppression and functioned independently of the autoinhibitory mechanism native to kinesin-1. Furthermore, the motor domain and proximal coiled coil of kinesin-1 were sufficient for HSV-1 assimilation, pUL37 suppression, and nuclear trafficking. pUL37 localized to the centrosome, the site of assimilated kinesin-1 activation during infection, when expressed in cells in the absence of other viral proteins; however, pUL37 did not suppress kinesin-1 in this context. These results indicate that the pUL37 tegument protein spatially and temporally regulates kinesin-1 via the amino-terminal motor region in the context of the incoming viral particle., Competing Interests: Competing interests statement:G.A.S. is a co-founder of Thyreos, Inc., which is producing recombinant herpesvirus vaccines based on technology covered in the current study. G.A.S. serves on the scientific advisory board of EG427. G.A.S. has stock ownership in two entities: Thyreos and EG427. G.A.S. is listed on a patent pertaining to herpesvirus vaccine design based on mutagenesis of the UL37 R2 effector.
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- 2024
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11. Elucidating Singlet-Fission-Born Multiexciton Dynamics via Molecular Engineering: A Dilution Principle Extended to Quintet Triplet Pair.
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Kim J, Teo HT, Hong Y, Cha H, Kim W, Chi C, and Kim D
- Abstract
Multiexciton in singlet exciton fission represents a critical quantum state with significant implications for both solar cell applications and quantum information science. Two distinct fields of interest explore contrasting phenomena associated with the geminate triplet pair: one focusing on the persistence of long-lived correlation and the other emphasizing efficient decorrelation. Despite the pivotal nature of multiexciton processes, a comprehensive understanding of their dependence on the structural and spin properties of materials is currently lacking in experimental realizations. To address this gap in knowledge, molecular engineering was employed to modify the TIPS-tetracene structures, enabling an investigation of the structure-property relationships in spin-related multiexciton processes. In lieu of the time-resolved electron paramagnetic resonance technique, two time-resolved magneto-optical spectroscopies were implemented for quantitative analysis of spin-dependent multiexciton dynamics. The utilization of absorption and fluorescence signals as complementary optical readouts, in the presence of a magnetic field, provided crucial insights into geminate triplet pair dynamics. These insights encompassed the duration of multiexciton correlation and the involvement of the spin state in multiexciton decorrelation. Furthermore, simulations based on our kinetic models suggested a role for quintet dilution in multiexciton dynamics, surpassing the singlet dilution principle established by the Merrifield model. The integration of intricate model structures and time-resolved magneto-optical spectroscopies served to explicitly elucidate the interplay between structural and spin properties in multiexciton processes. This comprehensive approach not only contributes to the fundamental understanding of these processes but also aligns with and reinforces previous experimental studies of solid states and theoretical assessments.
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- 2024
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12. Impact of Packing Geometry on Excimer Characteristics and Mobility in Perylene Bisimide Polycrystalline Films.
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Kang S, Choi W, Ahn J, Kim T, Oh JH, and Kim D
- Abstract
Efficient exciton transport is essential for high-performance optoelectronics. Considerable efforts have been focused on improving the exciton mobility in organic materials. While it is feasible to improve mobility in organic systems by forming well-ordered stacks, the formation of trap states, particularly the lower-lying states referred to as excimers, remains a significant challenge to enhancing mobility. The mobility of excimer excitons intricately depends on the strength of excitonic coupling in terms of Förster-type diffusive exciton transfer processes. Given that the formation and mobility of excimer excitons are highly sensitive to molecular arrangements (packing geometries), conducting comprehensive investigations into the structure-property relationship in organic systems is crucial. In this study, we prepared three types of polycrystalline films of perylene bisimide (PBI) by varying substituents at the imide and bay positions, which allowed us to tailor the properties of excimer excitons and their mobility based on packing geometries and excitonic coupling strengths. By utilizing femtosecond transient absorption spectroscopy, we observed ultrafast excimer formation in the higher coupling regime, while in the lower coupling regime, the transition from Frenkel to excimer excitons occurs with a time constant of 500 fs. Under high pump-fluence, exciton-exciton annihilation processes occur, indicating the diffusion of excimer excitons. Intriguingly, employing a three-dimensional diffusion model, we derived a diffusion constant that is 3000 times greater in the high coupling regime than in the low coupling regime. To investigate the optoelectronic properties in the form of a bulk system, we fabricated n -type organic field effect transistors and obtained 8000 times higher mobility in the high coupling regime. Furthermore, photocurrent measurements enable us to investigate the charge carrier transport by mobile excimer excitons, suggesting a 230-fold improvement in external quantum efficiency with tightly packing PBI molecules compared to the low coupling regime. These findings not only offer valuable insights into optimizing organic materials for optoelectronic devices but also unveil the intriguing potential of exciton migration within excimers.
- Published
- 2024
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13. A Janus carbaporphyrin pseudo-dimer.
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He H, Lee J, Zong Z, Kim J, Lynch VM, Oh J, Kim D, Sessler JL, and Ke XS
- Abstract
Carbaporphyrin dimers, investigated for their distinctive electronic structures and exceptional properties, have predominantly consisted of systems containing identical subunits. This study addresses the associated knowledge gap by focusing on asymmetric carbaporphyrin dimers with Janus-like characteristics. The synthesis of a Janus-type carbaporphyrin pseudo-dimer 5 is presented. It displays antiaromatic characteristics on the fused side and nonaromatic behavior on the unfused side. A newly synthesized tetraphenylene (TPE) linked bis-dibenzihomoporphyrin 8 and a previously reported dibenzo[g,p]chrysene (DBC) linked bis-dicarbacorrole 9 were prepared as controls. Comprehensive analyses, including
1 H NMR spectral studies, single crystal X-ray diffraction analyses, and DFT calculations, validate the mixed character of 5. A further feature of the Janus pseudo-dimer 5 is that it may be transformed into a heterometallic complex, with one side coordinating a Cu(III) center and the other stabilizing a BODIPY complex. This disparate regiochemical reactivity underscores the potential of carbaporphyrin dimers as versatile frameworks, with electronic features and site-specific coordination chemistry controlled through asymmetry. These findings position carbaporphyrin dimers as promising candidates for advances in electronic structure studies, coordination chemistry, materials science, and beyond., (© 2024. The Author(s).)- Published
- 2024
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14. Crystallographic and Photophysical Analysis on Facet-Controlled Defect-Free Blue-Emitting Quantum Dots.
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Lee YJ, Kim S, Lee J, Cho E, Won YH, Kim T, and Kim D
- Abstract
The burgeoning demand for commercializing self-luminescing quantum dot (QD) light-emitting diodes (LEDs) has stimulated extensive research into environmentally friendly and efficient QD materials. Hydrofluoric acid (HF) additive improves photoluminescence (PL) properties of blue-emitting ZnSeTe QDs, ultimately reaching a remarkable quantum yield (QY) of 97% with an ultranarrow peak width of 14 nm after sufficient HF addition. The improvement in optical properties of the QDs is accompanied by a morphology change of the particles, forming cubic-shaped defect-free ZnSeTe QDs characterized by a zinc blende (ZB) crystal structure. This treatment improves the QD-emitting properties by facilitating facet-specific growth, selectively exposing stabilized (100) facets, and reducing the lattice disorders. The facet-specific growth process gives rise to defect-free monodispersed cubic dots that exhibit remarkably narrow and homogeneous PL spectra. Meticulous time-resolved spectroscopic studies allow an understanding of the correlation between ZnSeTe QDs' particle shape and performance following HF addition. These investigations shed light on the intricacies of the growth mechanism and the factors influencing the PL efficiency of the resulting QDs. The findings significantly contribute to understanding the role of HF treatment in tailoring the optical properties of ZnSeTe QDs, thereby bringing it closer to the realization of highly efficient and bright QD-LEDs for various practical applications., (© 2024 Wiley‐VCH GmbH.)
- Published
- 2024
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15. Two-dimensional radial-π-stacks in solution.
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Su F, Hong Y, Zhang G, Wu K, Kim J, Chen Z, Zhang HJ, Kim D, and Lin J
- Abstract
Highly organized π-aggregate architectures can strongly affect electronic couplings, leading to important photophysical behaviors. With the escalating interest in two-dimensional (2D) materials attributed to their exceptional electronic and optical characteristics, there is growing anticipation that 2D radial-π-stacks built upon radial π-conjugation nanorings, incorporating intra- and inter-ring electronic couplings within the confines of a 2D plane, will exhibit superior topological attributes and distinct properties. Despite their immense potential, the design and synthesis of 2D π-stacks have proven to be a formidable challenge due to the insufficient π-π interactions necessary for stable stacking. In this study, we present the successful preparation of single-layer 2D radial-π-stacks in a solution. Pillar-shaped radially π-conjugated [4]cyclo-naphthodithiophene diimide ([4]C-NDTIs) molecules were tetragonally arranged via in-plane intermolecular π-π interactions. These 2D π-stacks have a unique topology that differs from that of conventional 1D π-stacks and exhibit notable properties, such as acting as a 2D template capable of absorbing C
60 guest molecules and facilitating the formation of 2D radial-π-stacks comprising [4]C-NDTI-C60 complexes, rapid exciton delocalization across the 2D plane, and efficient excitation energy funneling towards a trap., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2024
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16. Cyclic Azobenzene-BODIPY Hybrids.
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Wen B, Li C, Kang B, Zheng T, Wang Y, Jiang Y, Xu L, Oh J, Osuka A, Kim D, and Song J
- Abstract
Cyclic azobenzene-BODIPY hybrids were synthesized via cyclization by 1) acid-catalysed condensation of azobenzene-bridged dipyrroles with 3,5-di-tert-butylbenzaldehyde, 2) oxidation with DDQ, and 3) metalation with BF
3 ⋅ Et2 O. The structures of many cyclic hybrids have been confirmed by single crystal X-ray analysis. The absorption spectra of the hybrids reveal the effective cyclic conjugation. The ultrafast measurements reveal that the photoexcited decays of these cyclic hybrids depend upon the ring size and connectivity., (© 2023 Wiley-VCH GmbH.)- Published
- 2024
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17. Nanographene-Fused Expanded Carbaporphyrin Tweezers.
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He H, Lee YJ, Zong Z, Liu N, Lynch VM, Kim J, Oh J, Kim D, Sessler JL, and Ke XS
- Abstract
A nanographene-fused expanded carbaporphyrin ( 5 ) and its BF
2 complex ( 6 ) were synthesized. Single-crystal X-ray structures revealed that 5 and 6 are connected by two hexa- peri -hexabenzocoronene (HBC) units and two dipyrromethene or BODIPY units, respectively. As prepared, 5 and 6 both show nonaromatic character with figure-of-eight carbaoctaphyrin (1.1.1.0.1.1.1.0) cores and adopt tweezers-like conformations characterized by a partially confined space between the two constituent HBC units. The distance between the HBC centers is >10 Å, while the dihedral angles between the two HBC planes are 30.5 and 35.2° for 5 and 6 , respectively. The interactions between 5 and 6 and fullerene C60 were studied both in organic media and in the solid state. Proton NMR spectral titrations of 5 and 6 with C60 revealed a 1:1 binding mode for both macrocycles. In toluene- d8 , the corresponding binding constants were determined to be 1141 ± 17 and 994 ± 10 M-1 for 5 and 6 , respectively. Single-crystal X-ray diffraction structural analyses confirmed the formation of 1:1 fullerene inclusion complexes in the solid state. The C60 guests in both complexes are found within triangular pockets composed of two HBC units from the tweezers-like receptor most closely associated with the bound fullerene, as well as an HBC unit from an adjacent host. Femtosecond transient absorption measurements revealed subpicosecond ultrafast charge separation between 5 (and 6 ) and C60 in the complexes. To the best of our knowledge, the present report provides the first example wherein a nanographene building block is incorporated into the core of a porphyrinic framework.- Published
- 2024
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18. V-Shaped Tröger Oligothiophenes Boost Triplet Formation by CT Mediation and Symmetry Breaking.
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Medina Rivero S, Alonso-Navarro MJ, Tonnelé C, Marín-Beloqui JM, Suárez-Blas F, Clarke TM, Kang S, Oh J, Ramos MM, Kim D, Casanova D, Segura JL, and Casado J
- Abstract
A new family of molecules obtained by coupling Tröger's base unit with dicyanovinylene-terminated oligothiophenes of different lengths has been synthesized and characterized by steady-state stationary and transient time-resolved spectroscopies. Quantum chemical calculations allow us to interpret and recognize the properties of the stationary excited states as well as the time-dependent mechanisms of singlet-to-triplet coupling. The presence of the diazocine unit in Tröger's base derivatives is key to efficiently producing singlet-to-triplet intersystem crossing mediated by the role of the nitrogen atoms and of the almost orthogonal disposition of the two thiophene arms. Spin-orbit coupling-mediated interstate intersystem crossing (ISC) is activated by a symmetry-breaking process in the first singlet excited state with partial charge transfer character. This mechanism is a characteristic of these molecular triads since the independent dicyanovinylene-oligothiophene branches do not display appreciable ISC. These results show how Tröger's base coupling of organic chromophores can be used to improve the ISC efficiency and tune their photophysics.
- Published
- 2023
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19. π-Extended Hexapyrrolylbenzenes: Exploring Charge-Transfer Phenomena in Donor-Acceptor Propellers.
- Author
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Matuszczyk D, Lee YJ, Kang S, Chmielewski PJ, Cybińska J, Kim D, and Stępień M
- Abstract
A family of propeller-shaped donor-acceptor hexapyrrolylbenzenes (HPBs) were designed and synthesized by sequential nucleophilic substitution of hexafluorobenzene with π-extended pyrroles. In particular, four hybrids were obtained, containing various combinations of electron-rich and electron-poor acenaphthylene-fused pyrroles. Additionally, to probe the efficiency of ortho transfer interactions, a system was designed containing unique donor and acceptor subunits spatially separated with four unfunctionalized pyrroles. DFT calculations showed propeller-shaped geometries of all HPB molecules and separation of frontier molecular orbitals between donor and acceptor subunits. Steady-state and time-resolved photophysical measurements revealed charge-transfer (CT) character of the emission with strong positive dependence on solvent polarity. The principal CT pathway involves ortho-positioned pairs of donors and acceptors and requires bending of the acceptor in the excited state., (© 2023 Wiley-VCH GmbH.)
- Published
- 2023
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20. Stable Antiaromatic [24]Hexaphyrin(1.1.0.0.1.0) and Its Metal Complexes.
- Author
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Liu Y, Xu L, Rao Y, Kim J, Yin B, Zhou M, Oh J, Kim D, Song J, and Osuka A
- Abstract
5,10,23-Trimesityl-substituted [24]hexaphyrin(1.1.0.0.1.0) was synthesized as a stable antiaromatic molecule by base-catalyzed twofold S
N Ar reaction and was reduced to the corresponding [26]hexaphyrin, which was an unstable aromatic molecule because it easily oxidized to the [24]hexaphyrin. The [24]hexaphyrin served as a ligand to give the bis-PdII complex and tris-RhI complex with unique structures. The former complex has two square-planar-coordinated PdII ions bridged by an acetate anion and shows a strong paratropic ring current, while the latter complex has three RhI ions coordinated with two pyrrolic nitrogen atoms and two carbonyl groups, but one carbonyl group is shared with two RhI ions in a unique manner.- Published
- 2023
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21. Only cortical prediction error signals are involved in visual learning, despite availability of subcortical prediction error signals.
- Author
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Kim D, Wang Z, Sakagami M, Sasaki Y, and Watanabe T
- Abstract
Both the midbrain systems, encompassing the ventral striatum (VS), and the cortical systems, including the dorsal anterior cingulate cortex (dACC), play roles in reinforcing and enhancing learning. However, the specific contributions of signals from these regions in learning remains unclear. To investigate this, we examined how VS and dACC are involved in visual perceptual learning (VPL) through an orientation discrimination task. In the primary experiment, subjects fasted for 5 hours before each of 14 days of training sessions and 3 days of test sessions. Subjects were rewarded with water for accurate trial responses. During the test sessions, BOLD signals were recorded from regions including VS and dACC. Although BOLD signals in both areas were associated with positive and negative RPEs, only those in dACC associated with negative RPE showed a significant correlation with performance improvement. Additionally, no significant correlation was observed between BOLD signals associated with RPEs in VS and dACC. These results suggest that although signals associated with positive and negative RPEs from both midbrain and cortical systems are readily accessible, only RPE signals in the prefrontal system, generated without linking to RPE signals in VS, are utilized for the enhancement of VPL.
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- 2023
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22. Effect of BCR::ABL1 transcript type and droplet digital polymerase chain reaction on successful treatment-free remission in chronic myeloid leukemia patients who discontinued tyrosine kinase inhibitor.
- Author
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Park H, Kim HJ, Sohn SK, Baik Y, Kim D, Lee SY, Kong JH, Kim H, Shin DY, Ahn JS, Park J, Park S, and Kim I
- Abstract
Background: Droplet digital polymerase chain reaction (ddPCR) is an exact method of measurement., Objectives: We conducted this study to identify the prognostic factors for successful treatment-free remission in patients with chronic-phase chronic myeloid leukemia who discontinued tyrosine kinase inhibitors (TKIs). We also aimed to validate ddPCR for predicting molecular relapse., Design: This is a prospective, multicenter study., Methods: We enrolled patients treated with TKIs for at least 3 years with a confirmed sustained deep molecular response (DMR) for at least 1 year. TKI was re-administered in patients who experienced the loss of major molecular response (MMR)., Results: A total of 66 patients from five institutions in South Korea were enrolled. During a median follow-up period of 16.5 months, 29/66 (43.9%) patients experienced molecular relapse; the probability of molecular relapse-free survival (RFS) at 6 or 12 months after TKI discontinuation was 65.6% or 57.8%, respectively, with most molecular relapses occurring within the first 7 months. All patients who lost MMR were re-treated with TKI, and all re-achieved MMR at a median of 2.8 months. E14a2 transcript type ( p = 0.005) and longer DMR duration (⩾48 months) prior to TKI discontinuation ( p = 0.002) were associated with prolonged molecular RFS and with sustained DMR. Patients with both e13a2 transcript type and detectable BCR::ABL1 (⩾MR
5.0 ) by ddPCR at the time of TKI discontinuation showed shorter duration of molecular RFS ( p = 0.015)., Conclusion: Our data suggest that transcript type and BCR::ABL1 transcript levels on ddPCR should be taken into consideration when deciding whether to discontinue TKI therapy., Competing Interests: The authors declare that there is no conflict of interest., (© The Author(s), 2023.)- Published
- 2023
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23. Spatiotemporally Controllable Electrical Stimulator via Independent Photobending and Upconversion Photoluminescence Using Two Different Wavelengths of Near-Infrared/Visible Light as Dual Stimuli.
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Lee J, Kim D, Park M, Ryu J, Park H, Kim T, Kim D, Ju SY, and Kim J
- Abstract
Multistimuli responsive materials are advantageous in that they can enhance the desired response or bypass unwanted reactions. Light is one of the most attractive stimuli since it allows remote spatiotemporal control and multiplexing of properties (e.g., wavelength, intensity, irradiation time, pulsed/continuous wave) for application on multiphotoresponsive materials. However, the operating wavelength for such photoresponsive systems often includes an ultraviolet (UV) range that limits its use in the biomedical field. Herein, we investigate near-infrared (NIR)/visible (Vis) light-responsive nanocomposite films composed of rare earth element (i.e., Yb, Er)-doped NaYF
4 nanoparticles (NPs) embedded in azobenzene-incorporated poly(dimethylsiloxane) (AzoPDMS), silk fibroin, and silver nanowire (AgNW) layers. Photobending (PB) of the nanocomposite film is induced by a Vis light of 400-700 nm, while upconversion photoluminescence (UCPL) of embedded NPs is activated by an NIR light of 980 nm. The excitation wavelength of photoluminescence (PL) is shifted to the NIR (λ = 980 nm) range via photon upconversion in rare earth element-doped NPs. Independent operation of PB and UCPL enables both on-demand electrical switching and real-time location monitoring for spatiotemporally controlled electrical pulse stimulation. As a result, the dual-photoresponsive nanocomposite film can be utilized as a remotely controllable electrical stimulator and location indicator via different wavelengths of light.- Published
- 2023
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24. Tapered high-gain Fabry-Perot cavity antenna with high sidelobe suppression for 5G industry.
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Hussain M, Lee KG, and Kim D
- Abstract
We propose a Fabry-Perot cavity (FPC) antenna to suppress a sidelobe level (SLL) while maintaining a reasonably high gain. Generally, conventional FPC antennas (FPCAs) produce a high SLL because waves in their FPC leak considerably through lateral openings, which is a primary reason for lowering antenna gains. We propose two design approaches to solve this problem: the reflection magnitude tapering of a partially reflective surface (PRS) and considering different incident modes for the PRS design. First, the proposed tapering can remarkably reduce an SLL by providing the PRS with more radiation opportunities. Second, the different incident modes of transverse electric (TE) and transverse magnetic (TM) can increase an antenna gain by considering a more realistic illumination environment of the PRS. We have proven that our antenna provides 19.8 dBi realized gain with high sidelobe suppression (SLS) of more than 23 dB. Consequently, the proposed FPCA can suppress sidelobes significantly while maintaining a high gain. Good agreement between simulations and experiments demonstrates the usefulness of our proposal., (© 2023. Springer Nature Limited.)
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- 2023
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25. Leveraging Charge-Transfer Interactions in Through-Space-Coupled Pentacene Dendritic Oligomer for Singlet Exciton Fission.
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Kim J, Teo HT, Hong Y, Liau YC, Yim D, Han Y, Oh J, Kim H, Chi C, and Kim D
- Abstract
Singlet exciton fission in organic chromophores has received much attention during the past decade. Inspired by numerous spectroscopic studies in the solid state, there have been vigorous efforts to study singlet exciton fission dynamics in covalently bonded oligomers, which aims to investigate underlying mechanisms of this intriguing process in simplified model systems. In terms of through-space orbital interactions, however, most of covalently bonded pentacene oligomers studied so far fall into weakly interacting systems since they manifest chain-like structures based on various (non)conjugated linkers. Therefore, it remains as a compelling question to answer how through-space interactions in the solid state intervene this photophysical process since it is hypersensitive to displacements and orientations between neighboring chromophores. Herein, as one of experimental studies to answer this question, we introduced a tight-packing dendritic structure whose mesityl-pentacene constituents are coupled via moderate through-space orbital interactions. Based on the comparison with a suitably controlled dendritic structure, which is in a weak coupling regime, important mechanistic viewpoints are tackled such as configurational mixings between singlet, charge-transfer, and triplet pair states and the role of chromophore multiplication. We underscore that our through-space-coupled dendritic oligomer in a quasi-intermediate coupling regime provides a hint on the interplay of multiconfigurational excited-states, which might have drawn complexity in singlet exciton fission kinetics throughout numerous solid-state morphologies.
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- 2023
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26. Digital Therapeutics With Visual Discrimination Training for Cortical Blindness in Patients With Chronic Stroke.
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Lee EJ, Kim D, Kim YH, Namgung E, Lee JH, Sasaki Y, Watanabe T, and Kang DW
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- 2023
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27. Xanthene-Separated 24 π-Electron Antiaromatic Rosarin Dimer.
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Lee S, Wang Y, Dutta R, Lee CH, Sessler JL, and Kim D
- Abstract
Antiaromatic molecules have recently received attention because of their intrinsic properties, such as high reactivity and their narrow HOMO-LUMO gaps. Stacking of antiaromatic molecules has been predicted to induce three-dimensional aromaticity via frontier orbital interactions. Here, we report a covalently linked π-π stacked rosarin dimer that has been examined experimentally by steady-state absorption and transient absorption measurements and theoretically by quantum chemical calculations, including time-dependent density functional theory, anisotropy of induced current density, and nucleus-independent chemical shift calculations. Relative to the corresponding monomer, the dimer exhibits diminished antiaromaticity upon lowering the temperature to 77 K, a finding ascribed to intramolecular interactions between the macrocyclic rosarin subunits., (© 2023 Wiley-VCH Verlag GmbH.)
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- 2023
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28. Hybrid model for daily streamflow and phosphorus load prediction.
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Lee D, Shin J, Kim T, Lee S, Kim D, Park Y, and Cha Y
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- Meteorology, Phosphorus, Republic of Korea, Climate Change, Hydrology
- Abstract
Environmental factors, such as climate change and land use changes, affect water quality drastically. To consider these, various predictive models, both process-based and data-driven, have been used. However, each model has distinct limitations. In this study, a hybrid model combining the soil and water assessment tool and the reverse time attention mechanism (SWAT-RETAIN) was proposed for predicting daily streamflow and total phosphorus (TP) load of a watershed. SWAT-RETAIN was applied to Hwangryong River, South Korea. The hybrid model uses the SWAT output as input data for the RETAIN. Spatial, meteorological, and hydrological data were collected to develop the SWAT to generate high temporal resolution data. RETAIN facilitated effective simultaneous prediction. The SWAT-RETAIN exhibited high accuracy in predicting streamflow (Nash-Sutcliffe efficiency (NSE): 0.45, root mean square error (RMSE): 27.74, percent bias (PBIAS): 22.63 for test sets), and TP load (NSE: 0.50, RMSE: 423.93, PBIAS: 22.09 for test sets). This result was evident in the performance evaluation using flow duration and load duration curves. The SWAT-RETAIN provides enhanced temporal resolution and performance, enabling the simultaneous prediction of multiple variables. It can be applied to predict various water quality variables in larger watersheds.
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- 2023
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29. Direct Probing of Lattice-Strain-Induced Oxygen Release in LiCoO 2 and Li 2 MnO 3 without Electrochemical Cycling.
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Kim D, Hwang J, Byeon P, Kim W, Kang DG, Bae HB, Lee SG, Han SM, Lee J, and Chung SY
- Abstract
Since the recognition of a significant oxygen-redox contribution to enhancing the capacity of Li transition-metal oxide cathodes, the oxygen release and subsequent structural variations together with capacity fading are critical issues to achieve better electrochemical performance. As most previous reports dealt with the structural degradation of cathodes after electrochemical cycling, it is fairly difficult to clarify how substantial the effect of lattice strain on the oxygen release will be while exclusively ruling out any electrochemical influences. By utilizing nanoindentation and mechanical surface polishing of single-crystal LiCoO
2 and Li2 MnO3 , the local variations of both the atomic structure and oxygen content are scrutinized. Atomic-column-resolved imaging reveals that local LiM (M = Co and Mn) disordering and further amorphization are induced by mechanical strain. Moreover, substantial oxygen deficiency in the regions with these structural changes is directly identified by spectroscopic analyses. Ab initio density functional theory calculations also demonstrate energetically favorable formation of oxygen vacancies under shear strain. Providing direct evidence of oxygen release as a consequence of lattice strain, the findings in this work suggest that efficient strain relaxation will be of great significance for longevity of the anion framework in layered oxide cathodes., (© 2023 Wiley-VCH GmbH.)- Published
- 2023
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30. A multi-targeting bionanomatrix coating to reduce capsular contracture development on silicone implants.
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Hwang P, Shin CM, Sherwood JA, Kim D, Vijayan VM, Josyula KC, Millican RC, Ho D, Brott BC, Thomas V, Choi CH, Oh SH, Kim DW, and Jun HW
- Abstract
Background: Capsular contracture is a critical complication of silicone implantation caused by fibrotic tissue formation from excessive foreign body responses. Various approaches have been applied, but targeting the mechanisms of capsule formation has not been completely solved. Myofibroblast differentiation through the transforming growth factor beta (TGF-β)/p-SMADs signaling is one of the key factors for capsular contracture development. In addition, biofilm formation on implants may result chronic inflammation promoting capsular fibrosis formation with subsequent contraction. To date, there have been no approaches targeting multi-facted mechanisms of capsular contracture development., Methods: In this study, we developed a multi-targeting nitric oxide (NO) releasing bionanomatrix coating to reduce capsular contracture formation by targeting myofibroblast differentiation, inflammatory responses, and infections. First, we characterized the bionanomatrix coating on silicon implants by conducting rheology test, scanning electron microcsopy analysis, nanoindentation analysis, and NO release kinetics evaluation. In addition, differentiated monocyte adhesion and S. epidermidis biofilm formation on bionanomatrix coated silicone implants were evaluated in vitro. Bionanomatrix coated silicone and uncoated silicone groups were subcutaneously implanted into a mouse model for evaluation of capsular contracture development for a month. Fibrosis formation, capsule thickness, TGF-β/SMAD 2/3 signaling cascade, NO production, and inflammatory cytokine production were evaluated using histology, immunofluorescent imaging analysis, and gene and protein expression assays., Results: The bionanomatrix coating maintained a uniform and smooth surface on the silicone even after mechanical stress conditions. In addition, the bionanomatrix coating showed sustained NO release for at least one month and reduction of differentiated monocyte adhesion and S. epidermidis biofilm formation on the silicone implants in vitro. In in vivo implantation studies, the bionanomatrix coated groups demonstrated significant reduction of capsule thickness surrounding the implants. This result was due to a decrease of myofibroblast differentiation and fibrous extracellular matrix production through inhibition of the TGF-β/p-SMADs signaling. Also, the bionanomatrix coated groups reduced gene expression of M1 macrophage markers and promoted M2 macrophage markers which indicated the bionanomatrix could reduce inflammation but promote healing process., Conclusions: In conclusion, the bionanomatrix coating significantly reduced capsular contracture formation and promoted healing process on silicone implants by reducing myfibroblast differentiation, fibrotic tissue formation, and inflammation. A multi-targeting nitric oxide releasing bionanomatrix coating for silicone implant can reduce capsular contracture and improve healing process. The bionanomatrix coating reduces capsule thickness, α-smooth muscle actin and collagen synthesis, and myofibroblast differentiation through inhibition of TGF-β/SMADs signaling cascades in the subcutaneous mouse models for a month., (© 2023. The Author(s).)
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- 2023
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31. Charge Injection and Energy Transfer of Surface-Engineered InP/ZnSe/ZnS Quantum Dots.
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Park J, Kim T, and Kim D
- Abstract
Surface passivation is a critical aspect of preventing surface oxidation and improving the emission properties of nanocrystal quantum dots (QDs). Recent studies have demonstrated the critical role of surface ligands in determining the performance of QD-based light-emitting diodes (QD-LEDs). Herein, the underlying mechanism by which the capping ligands of InP/ZnSe/ZnS QDs influence the brightness and lifetime of the QD-LEDs is investigated. The electrochemical results demonstrate that highly luminescent InP/ZnSe/ZnS QDs exhibit modulated charge injection depending on the length of the surface ligand chains: short alkyl chains on the ligands are favorable for charge transport to the QDs. In addition, the correlation between the spectroscopic and XRD analyses suggests that the length of the ligand chain tunes the ligand-ligand coupling strength, thereby controlling the inter-QD energy transfer dynamics. The present findings shed new light on the crucial role of surface ligands for InP/ZnSe/ZnS QD-LED applications.
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- 2023
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32. Metformin regulates expression of DNA methyltransferases through the miR-148/-152 family in non-small lung cancer cells.
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Lee BB, Kim D, Kim Y, Han J, Shim YM, and Kim DH
- Subjects
- Humans, 3' Untranslated Regions, DNA Methylation, Gene Expression Regulation, Neoplastic, DNA Modification Methylases genetics, DNA metabolism, Cell Line, Tumor, Cell Proliferation, Lung Neoplasms drug therapy, Lung Neoplasms genetics, Lung Neoplasms metabolism, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung genetics, Carcinoma, Non-Small-Cell Lung metabolism, Metformin pharmacology, MicroRNAs genetics, MicroRNAs metabolism
- Abstract
Background: To understand the molecular mechanisms involved in regulation of DNA methyltransferases (DNMTs) by metformin in non-small cell lung cancer (NSCLC) cells., Methods: Expression levels of DNMTs in response to metformin were analyzed in NSCLC cells. MicroRNAs regulating expression of DNMTs at the post-transcriptional level were searched using miRNA-target databases (miRDB and miRTarBase), TCGA RNASeqV2 lung cancer data, and miRNA-seq., Results: Metformin dose-dependently downregulated expression of DNMT1 and DNMT3a at the post-transcriptional level and expression of DNMT3b at the transcriptional level in A549 lung cancer cells. Activity of DNMTs was reduced by about 2.6-fold in A549 cells treated with 10 mM metformin for 72 h. miR-148/-152 family members (miR-148a, miR-148b, and miR-152) targeting the 3'UTR of DNMTs were associated with post-transcriptional regulation of DNMTs by metformin. Metformin upregulated expression of miR-148a, miR-148b, and miR-152 in A549 and H1650 cells. Transfection with an miR-148b plasmid or a mimic suppressed expression of DNMT1 and DNMT3b in A549 cells. Transfection with the miR-148a mimic in A549 and H1650 cells decreased the luciferase activity of DNMT1 3'UTR. A combination of metformin and cisplatin synergistically increased expression levels of miR-148/-152 family members but decreased expression of DNMTs in A549 cells. Low expression of miR-148b was associated with poor overall survival (HR = 2.56, 95% CI 1.09-6.47; P = 0.04) but not with recurrence-free survival., Conclusions: The present study suggests that metformin inhibits expression of DNMTs by upregulating miR-148/-152 family members in NSCLC cells., (© 2023. The Author(s).)
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- 2023
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33. Aromatic-bridged and meso-meso-linked BF 2 -smaragdyrin dimers exhibit fast decays in polar solvents by symmetry-breaking charge transfer.
- Author
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Wen L, Cao X, Lee S, Xu L, Rao Y, Kang S, Kim D, Osuka A, and Song J
- Abstract
Symmetry-breaking charge transfer is one of the key process in photosynthetic reaction centers and specific artificial optoelectronic devices such as dye-sensitized solar cells. Here we report the synthesis of aromatic-bridged BF
2 -smaragdyrin dimers, meso-free BF2 -smaragdyrin, and its meso-meso-linked BF2 -smaragdyrin dimer. The decays of S1 -states of these dimers are accelerated with an increase in solvent polarity and a decrease in the distance between the two BF2 -smaragdyrin units, suggesting symmetry-breaking charge transfer. The fluorescence lifetimes of the dimers become shortened in polar solvents. However, ultrafast transient absorption spectroscopy do not detect charge-separated ion pairs. On the basis of these results, we conclude that the decays of the excited states of the BF2 -smaragdyrin dimers are accelerated by solvation-induced symmetry-breaking charge transfer, depending on the degree of the electronic interaction between the smaragdryin units as a rare case for porphyrinoids. The degree of charge transfer is larger for dimers with larger electronic interactions., (© 2023. The Author(s).)- Published
- 2023
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34. Cyclic Carbaporphyrin Arrays.
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He H, Lee S, Liu N, Zhang X, Wang Y, Lynch VM, Kim D, Sessler JL, and Ke XS
- Abstract
Two cyclic carbaporphyrin arrays (trimer 6 and tetramer 7 ) were synthesized from a dibrominated carbaporphyrin precursor ( 5 ) via a one-pot Yamamoto-type coupling. Single-crystal X-ray diffraction analyses revealed that 6 and 7 contain three and four covalently linked carbaporphyrin (formally dicarbacorrole) units, respectively. Trimer 6 adopts a roughly planar conformation and tetramer 7 adopts an up-and-down zig-zag conformation. Both 6 and 7 contain a [n]cyclo-meta-phenylene ([n]CMP) core, namely, [6]- and [8]CMP for 6 and 7 , respectively. Transient absorption (TA) anisotropy and pump-power-dependent excited-state decay studies provided evidence for excitation energy transfer (EET) within both trimer 6 and tetramer 7 . The exciton energy hopping (EEH) times were estimated to be 18 and 35 ps for 6 and 7 , respectively, as inferred from pump-power-dependent TA measurements. Since the center-to-center distances between adjacent carbaporphyrin units are similar in 6 and 7 , the different EEH times are attributed to differences in the orientation of the transition dipoles in these two congeneric arrays. The orientation factor κ
2 , the key parameter defining the Förster resonance energy transfer efficiency, was calculated to be 2.15 and 1.03 for 6 and 7 , respectively, a finding that supports the shorter excitation energy hopping time seen in the case of trimer 6 . To our knowledge, this is the first time that covalently linked cyclic carbaporphyrin arrays were synthesized using a single carbaporphyrin as the starting point and that EET between carbaporphyrin subunits constrained within a well-defined polycyclic framework has been correlated with structural differences.- Published
- 2023
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35. Realization of Stacked-Ring Aromaticity in a Water-Soluble Micellar Capsule.
- Author
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Liu SY, Kishida N, Kim J, Fukui N, Haruki R, Niwa Y, Kumai R, Kim D, Yoshizawa M, and Shinokubo H
- Abstract
Stacked-ring aromaticity arising from the close stacking of antiaromatic π-systems has recently received considerable attention. Here, we realize stacked-ring aromaticity via a rational supramolecular approach. A nanocapsule composed of bent polyaromatic amphiphiles was employed to encapsulate several antiaromatic norcorrole Ni(II) complexes (NCs) in water. The resulting micellar capsules display high stability toward heating and concentration change. The encapsulation resulted in the appearance of a broad absorption band in the near-infrared region, which is characteristic of norcorroles with close face-to-face stacking. Importantly, a meso -isopropyl NC, which does not exhibit π-stacking even in a concentrated solution or the crystalline phase, adopted π-stacking with stacked-ring aromaticity in the supramolecular micellar capsule.
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- 2023
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36. Peak systolic myocardial velocity in patients undergoing surgical aortic valve replacement for severe aortic stenosis: prognostic value and natural course.
- Author
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Chin JH, Kim S, Kim D, Nam JS, Kim K, and Choi IC
- Subjects
- Humans, Echocardiography, Doppler, Prognosis, Systole, Aortic Valve surgery, Aortic Valve Stenosis surgery
- Abstract
Myocardial systolic longitudinal function has been known to decrease in patients with severe aortic stenosis (AS). Preoperative peak systolic myocardial velocity at the septal mitral valve annulus (S'), measured using Doppler tissue imaging, was used as an indicator for myocardial systolic longitudinal function. The prognostic value and natural course of S' after surgical aortic valve replacement for severe AS have not been elucidated. This retrospective observational study included patients from January 2006 to December 2018. The patients were divided to 2 groups (pre-S'
HIGH vs. pre-S'LOW ) with a cut-off 5.4 cm/s of preoperative S' (pre-S') that was identified by restricted cubic spline curve. The primary outcome was postoperative long-term all-cause mortality. Nine hundred and five patients were analyzed. All-cause mortality rate at the median follow-up period of 5.2 years was 12% in pre-S'LOW and 8% in pre-S'HIGH . Multivariate analysis showed that pre-S'LOW was associated with an increased all-cause mortality (hazard ratio, 1.60; 95% confidence interval, 1.04-2.48; P = 0.032). Significantly different trajectories of postoperative S' (post-S') were found between two groups (P < 0.001 for difference): In pre-S'LOW , post-S' increased within 6 months after surgery, and gradually decreased over time, whereas it slowly decreased up to 5 years after surgery and then reached a plateau in pre-S'HIGH. The difference in pre-S' level maintained over time, and remained consistent in the adjusted analysis. Pre-S' < 5.4 cm/s was found to be associated with an increased long-term all-cause mortality. In addition, the trajectories for post-S' were different according to pre-S', which remained after adjustment., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)- Published
- 2023
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37. Ultrafast Excited State Aromatization in Dihydroazulene.
- Author
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Shostak S, Park W, Oh J, Kim J, Lee S, Nam H, Filatov M, Kim D, and Choi CH
- Abstract
Excited-state aromatization dynamics in the photochemical ring opening of dihydroazulene (DHA) is investigated by nonadiabatic molecular dynamics simulations in connection with the mixed-reference spin-flip (MRSF)-TDDFT method. It is found that, in the main reaction channel, the ring opening occurs in the excited state in a sequence of steps with increasing aromaticity. The first stage lasting ca. 200 fs produces an 8π semiaromatic S
1 minimum (S1, min ) through an ultrafast damped bond length alternation (BLA) movement synchronized with a partial planarization of the cycloheptatriene ring. An additional ca. 200 fs are required to gain the vibrational energy needed to overcome a ring-opening transition state characterized by an enhanced Baird aromaticity. Unlike other BLA motions of ππ * state, it was shown that their damping is a characteristic feature of aromatic bond-equalization process. In addition, some minor channels of the reaction have also been discovered, where noticeably higher barriers of the S1 non/antiaromatic transition structures must be surmounted. These anti-Baird channels led to reformation of DHA or other closed-ring products. The observed competition between the Baird and anti-Baird channels suggests that the quantum yield of photochemical products can be controllable by tipping their balance. Hence, here we suggest including the concept of anti-Baird, which would expand the applicability of Baird rule to much broader situations.- Published
- 2023
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38. Synthesis of Subporphyrin Free Bases.
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Liu L, Kim J, Xu L, Rao Y, Zhou M, Yin B, Oh J, Kim D, Osuka A, and Song J
- Abstract
B
III subporphyrins are the legitimate ring-contracted porphyrins consisting of three pyrroles and three meso-carbons and their chemistry has been extensively developed since the first synthesis in 2006. However, subporphyrin free bases have never been synthesized, despite tremendous attempts to remove the BIII ion. Here we report that Suzuki-Miyaura coupling between α,α'-diborylated tripyrrane 1 and tetrabromide 5 gave subporphyrin free bases 6, 6 A, and free base dimer 7 in 6 %, 4 %, and 2 % yields as the first examples. Subporphyrin free bases exhibit curved bowl-like structures and distinct 14π-aromaticity. Steady-state and time-resolved spectroscopy revealed that the excited-state behaviors of the subporphyrin free bases are comparable with those of the corresponding BIII subporphyrins. Rotational relaxation processes in the excited states have been revealed, which enhance the electronic interactions with the meso-aryl substituents and between the two subporphyrins., (© 2022 Wiley-VCH GmbH.)- Published
- 2022
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39. Ultrafast Symmetry-Breaking Charge Separation in a Perylene Bisimide Dimer Enabled by Vibronic Coupling and Breakdown of Adiabaticity.
- Author
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Hong Y, Schlosser F, Kim W, Würthner F, and Kim D
- Abstract
Perylene bisimides (PBIs) have received great attention in their applicability to optoelectronics. Especially, symmetry-breaking charge separation (SB-CS) in PBIs has been investigated to mimic the efficient light capturing and charge generation in natural light-harvesting systems. However, unlike ultrafast CS dynamics in donor-acceptor heterojunction materials, ultrafast SB-CS in a stacked homodimer has still been challenging due to excimer formation in the absence of rigidifying surroundings such as a special pair in the natural systems. Herein, we present the detailed mechanism of ultrafast photoinduced SB-CS occurring in a 1,7-bis( N -pyrrolidinyl) PBI dimer within a cyclophane. Through narrow-band and broad-band transient absorption spectroscopy, we demonstrate that ultrafast SB-CS in the dimer is enabled by the combination of (1) vibrationally coherent charge-transfer resonance-enhanced excimer formation and (2) breakdown of adiabaticity (formation of SB-CS diabats) in the excimer state via structural and solvent fluctuation. Quantum chemical calculations also underpin that the participation of strong electron-donating substituents in overall vibrational modes plays a crucial role in triggering the ultrafast SB-CS. Therefore, our work provides an alternative route to facilitate ultrafast SB-CS in PBIs and thereby establishes a novel strategy for the design of optoelectronic materials.
- Published
- 2022
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40. Steering the multiexciton generation in slip-stacked perylene dye array via exciton coupling.
- Author
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Hong Y, Rudolf M, Kim M, Kim J, Schembri T, Krause AM, Shoyama K, Bialas D, Röhr MIS, Joo T, Kim H, Kim D, and Würthner F
- Abstract
Dye arrays from dimers up to larger oligomers constitute the functional units of natural light harvesting systems as well as organic photonic and photovoltaic materials. Whilst in the past decades many photophysical studies were devoted to molecular dimers for deriving structure-property relationship to unravel the design principles for ideal optoelectronic materials, they fail to accomplish the subsequent processes of charge carrier generation or the detachment of two triplet species in singlet fission (SF). Here, we present a slip-stacked perylene bisimide trimer, which constitutes a bridge between hitherto studied dimer and solid-state materials, to investigate SF mechanisms. This work showcases multiple pathways towards the multiexciton state through direct or excimer-mediated mechanisms by depending upon interchromophoric interaction. These results suggest the comprehensive role of the exciton coupling, exciton delocalization, and excimer state to facilitate the SF process. In this regard, our observations expand the fundamental understanding the structure-property relationship in dye arrays., (© 2022. The Author(s).)
- Published
- 2022
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41. Impact of Sex on Mortality in Patients Undergoing Surgical Aortic Valve Replacement.
- Author
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Kang HU, Nam JS, Kim D, Kim K, Chin JH, and Choi IC
- Abstract
Aortic stenosis (AS) is the second most common valvular heart disease in the United States. Although the prevalence of AS does not significantly differ between the sexes, there is some controversy on whether sex differences affect the long-term mortality of patients with severe AS undergoing surgical aortic valve replacement (SAVR). Therefore, we retrospectively analyzed the medical records of 917 patients (female, n = 424 [46.2%]) with severe AS who had undergone isolated SAVR at a tertiary care center between January 2005 and December 2018. During a median follow-up of 5.2 years, 74 (15.0%) male patients and 41 (9.7%) female patients died. The Kaplan-Meier analysis revealed that the 10-year mortality rate was significantly higher in male than female patients (24.7% vs. 17.9%, log-rank p = 0.005). In the sequential Cox proportional hazard regression model for assessing long-term mortality up to 10 years post-surgery, the adjusted hazard ratio of male sex for mortality was 1.93 (95% confidence interval, 1.28-2.91; p = 0.002). The association between male sex and postoperative long-term mortality was not significantly diminished by any demographic or clinical factor in subgroup analyses. In conclusion, female sex was significantly associated with better long-term survival in patients with severe AS undergoing SAVR.
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- 2022
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42. Naphthalimide-Fused Dipyrrins: Tunable Halochromic Switches and Photothermal NIR-II Dyes.
- Author
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Maurya YK, Chmielewski PJ, Cybińska J, Prajapati B, Lis T, Kang S, Lee S, Kim D, and Stępień M
- Subjects
- Electrons, Coloring Agents, Naphthalimides
- Abstract
A family of tunable halochromic switches is developed using a naphthalimide-fused dipyrrin as the core π-conjugated motif. Electronic properties of these dipyrrins are tuned by substitution of their alpha and meso positions with aryl groups of variable donor-acceptor strength. The first protonation results in a conformational change that enhances electronic coupling between the dipyrrin chromophore and the meso substituent, leading to halochromic effects that occasionally exceed 200 nm and switch the absorption between the near-infrared (NIR)-I and NIR-II ranges. A NIR-II photothermal effect, switchable by acid-base chemistry is demonstrated for selected dipyrrins. Further protonation is possible for derivatives bearing additional amino groups, leading to up to four halochromic switching step. The most electron-rich dipyrrins are also susceptible to chemical oxidation, yielding NIR-absorbing radical cations and closed-shell dications., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)
- Published
- 2022
- Full Text
- View/download PDF
43. Protonation-Induced Antiaromaticity in Octaaza[8]circulenes: Cyclooctatetraene Scaffolds Constrained with Four Amidine Moieties.
- Author
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Akahori S, Kaga A, Kim J, Yorimitsu H, Kim D, Shinokubo H, and Miyake Y
- Subjects
- Crystallography, X-Ray, Molecular Structure, Amidines
- Abstract
The switching of cyclic π-conjugation pathways using external stimuli is an attractive research topic in the field of organic chemistry. Here, we synthesized C
4h -symmetric octaaza[8]circulenes with four peripherally arranged amidine moieties that exhibit enhanced antiaromaticity upon protonation. Titration experiments with methanesulfonic acid revealed the formation of the tetraprotonated forms of the octaaza[8]circulenes in solution. Single-crystal X-ray diffraction analyses and theoretical calculations indicated that the contribution of the 8π antiaromatic character of the octaaza[8]circulenes is enhanced by the delocalization of charge through the protonation of the pyridine rings., (© 2022 Wiley-VCH GmbH.)- Published
- 2022
- Full Text
- View/download PDF
44. Engineered Surface Halide Defects by Two-Dimensional Perovskite Passivation for Deformable Intelligent Photodetectors.
- Author
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Kim T, Jeong S, Kim KH, Shim H, Kim D, and Kim HJ
- Abstract
As attractive photoactive materials, metal halide perovskites demonstrate outstanding performance in a wide range of optoelectronic applications. Among the various compositions studied, mixed-halide perovskites have a finely tunable band gap that renders them desirable for targeted applications. Despite their advantages, photoinduced halide segregation often deters the photoelectric stability of the materials. Herein, we adopt a strategy of post-treating the perovskite surface with an organic spacer to generate a two-dimensional (2D) perovskite passivating layer. Trap-assisted recombination pathways can be selectively modulated by passivating the surface halide defects that cause photoinduced halide segregation. Fluorescence lifetime imaging of flat and bent surfaces of perovskites reveals that the perovskite lattice tolerates mechanical strain via the neutralizing passivation of ionic halide defects. Upon bending, the photocurrent response of the flexible photodetector is maintained over 83% for 2D passivated perovskite and drops to 23% for pristine perovskite. A flexible photodetector array built with 2D passivated perovskite, in combination with a deep learning algorithm, demonstrates excellent accuracy in determining letters of the alphabet for both flat (>96%) and bent (>93%) states. The connection of chemically modified charge carrier dynamics and mechanical properties revealed in this study offers valuable guidance for developing next-generation optoelectronic applications.
- Published
- 2022
- Full Text
- View/download PDF
45. Self-Assembled Size-Tunable Microlight-Emitting Diodes Using Multiple Sapphire Nanomembranes.
- Author
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Oh J, Kim D, Yang D, Hwang K, Hwang J, Kim J, Lee S, Ryu J, Park S, Shin JK, Kim Y, Park Y, Yoon E, and Jang HW
- Abstract
Microlight-emitting diode (Micro-LED) is the only display production technology capable of meeting the high-performance requirements of future screens. However, it has significant obstacles in commercialization due to etching loss and efficiency reduction caused by the singulation process, in addition to expensive costs and a significant amount of time spent on transfer. Herein, multiple-sapphire nanomembrane (MSNM) technology has been developed that enables the rapid transfer of arrays while producing micro-LEDs without the need for any singulation procedure. Individual micro-LEDs of tens of μm size were formed by the pendeo-epitaxy and coalescence of GaN grown on 2 μm width SNMs spaced with regular intervals. We have successfully fabricated micro-LEDs of different sizes including 20 × 20 μm
2 , 40 × 40 μm2 , and 100 × 100 μm2 , utilizing the membrane design. It was confirmed that the 100 × 100 μm2 micro-LED manufactured with MSNM technology not only relieved stress by 80.6% but also reduced threading dislocation density by 58.7% compared to the reference sample. It was proven that micro-LED arrays of varied chip sizes using MSNM were all transferred to the backplane. A vertical structure LED device could be fabricated using a 100 × 100 μm2 micro-LED chip, and it was confirmed to have a low operation voltage. Our work suggests that the development of the MSNM technology is promising for the commercialization of micro-LED technology.- Published
- 2022
- Full Text
- View/download PDF
46. Neural mechanisms of pain relief through paying attention to painful stimuli.
- Author
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Kim D, Woo CW, and Kim SG
- Subjects
- Analgesics, Brain Mapping, Humans, Pain Measurement, Parietal Lobe, Pain, Pain Management
- Abstract
Abstract: A commonly held belief suggests that turning one's attention away from pain reduces it, whereas paying attention to pain increases it. However, some attention-based therapeutic strategies for pain, such as mindfulness-based interventions, suggest that paying attention to painful stimuli can reduce pain, resulting in seemingly contradictory conclusions regarding attention and pain. Here, we investigated the analgesic effects of attention modulation and provide behavioral and neural evidence that paying attention to pain can reduce pain when attention is directed toward the specific features of painful stimuli. The analgesic effects of paying attention to painful stimuli were mediated by the primary somatosensory cortex and goal-directed attention regions in the prefrontal and parietal cortex. These findings suggest that suppressing early somatosensory processing through top-down modulation is the key mechanism of the analgesic effects of paying attention to painful stimuli, providing evidence that pain itself can be used as a component of pain management., (Copyright © 2021 International Association for the Study of Pain.)
- Published
- 2022
- Full Text
- View/download PDF
47. Pyrene-Bridged Expanded Carbaporphyrin Nanobelts.
- Author
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Wang Y, Ke XS, Lee S, Kang S, Lynch VM, Kim D, and Sessler JL
- Subjects
- Crystallography, X-Ray, Spectrometry, Fluorescence, Pyrenes
- Abstract
Two belt-like expanded carbaporphyrins ( NB1 and NB2 ) were prepared via a one-pot procedure that involves a [6 + 3] condensation between a pyrene-bearing tetrapyrrole precursor ( 2 ) and pentafluorobenzaldehyde, followed by oxidation. Single crystal X-ray diffraction analyses revealed that NB1 and NB2 both contain six dipyrromethene moieties and three bridging pyrene units. In the structure of NB1 , there are two vertically orientated pyrene units and one transverse orientated pyrene unit; however, in NB2 all three pyrene units are vertically orientated. The structural differences between NB1 and NB2 are reflected in their respective physical properties as revealed by proton NMR, UV-vis, and fluorescence spectroscopies. In contrast to all-carbon nanobelts, NB1 and NB2 contain multiple pyrrolic nitrogen donors that could serve as potential metal coordination sites. As a test of this possibility, NB2 was used to prepare an unprecedented Zn complex containing 7 Zn
2+ metal centers connected by a network of bridging atoms, as confirmed by a single crystal X-ray diffraction analysis. To the best of our knowledge, this is the first example of a belt-like molecular system that can coordinate multiple metal ions both along the backbone and within its central cavity.- Published
- 2022
- Full Text
- View/download PDF
48. 5-Thiaporphyrinium cation: effect of sulphur incorporation on excited state dynamics.
- Author
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Takiguchi A, Inai N, Kang S, Hagai M, Lee S, Yanai T, Kim D, and Shinokubo H
- Subjects
- Cations, Fluorescence, Sulfur, Quantum Theory, Vibration
- Abstract
We synthesised thionium-ion embedded aromatic porphyrinoids: a free-base 5-thiaporphyrinium cation and its zinc complex. The sulphur atom effectively participates in the macrocyclic π-conjugation. Fluorescence quantum yields of thiaporphyrinium cations were lower than 1% unlike oxaporphyrinium cations. Detailed photophysical analysis and DFT calculations clarified the vibrational mode regarding the out-of-plane motion of the sulphur atom induced ultrafast quenching of the excited state in comparison to the corresponding oxaporphyrinium cations.
- Published
- 2022
- Full Text
- View/download PDF
49. Shape-Tuned Multiphoton-Emitting InP Nanotetrapods.
- Author
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Kim T, Kim Y, Park S, Park K, Wang Z, Oh SH, Jeong S, and Kim D
- Abstract
As the properties of a semiconductor material depend on the fate of the excitons, manipulating exciton behavior is the primary objective of nanomaterials. Although nanocrystals exhibit unusual excitonic characteristics owing to strong spatial confinement, studying the interactions between excitons in a single nanoparticle remains challenging due to the rapidly vanishing multiexciton species. Here, a platform for exciton tailoring using a straightforward strategy of shape-tuning of single-crystalline nanocrystals is presented. Spectroscopic and theoretical studies reveal a systematic transition of exciton confinement orientation from 3D to 2D, which is solely tuned by the geometric shape of material. Such a precise shape-effect triggers a multiphoton emission in single nanotetrapods with arms longer than the exciton Bohr radius of material. In consequence, the unique interplay between the multiple quantum states allows a geometric modulation of the quantum-confined Stark effect and nanocrystal memory effect in single nanotetrapods. These results provide a useful metric in designing nanomaterials for future photonic applications., (© 2022 Wiley-VCH GmbH.)
- Published
- 2022
- Full Text
- View/download PDF
50. Real-time Observation of Structural Dynamics Triggering Excimer Formation in a Perylene Bisimide Folda-dimer by Ultrafast Time-Domain Raman Spectroscopy.
- Author
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Hong Y, Kim W, Kim T, Kaufmann C, Kim H, Würthner F, and Kim D
- Abstract
In π-conjugated organic photovoltaic materials, an excimer state has been generally regarded as a trap state which hinders efficient excitation energy transport. But despite wide investigations of the excimer for overcoming the undesirable energy loss, the understanding of the relationship between the structure of the excimer in stacked organic compounds and its properties remains elusive. Here, we present the landscape of structural dynamics from the excimer formation to its relaxation in a co-facially stacked archetypical perylene bisimide folda-dimer using ultrafast time-domain Raman spectroscopy. We directly captured vibrational snapshots illustrating the ultrafast structural evolution triggering the excimer formation along the interchromophore coordinate on the complex excited-state potential surfaces and following evolution into a relaxed excimer state. Not only does this work showcase the ultrafast structural dynamics necessary for the excimer formation and control of excimer characteristics but also provides important criteria for designing the π-conjugated organic molecules., (© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)
- Published
- 2022
- Full Text
- View/download PDF
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