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Universal process-inert encoding architecture for polymer microparticles
Lee, Jiseok,Bisso, Paul W.,Srinivas, Rathi L.,Kim, Jae Jung,Swiston, Albert J.,Doyle, Patrick S. Nature Publishing Group, a division of Macmillan P 2014 NATURE MATERIALS Vol.13 No.5
Polymer microparticles with unique, decodable identities are versatile information carriers with a small footprint. Widespread incorporation into industrial processes, however, is limited by a trade-off between encoding density, scalability and decoding robustness in diverse physicochemical environments. Here, we report an encoding strategy that combines spatial patterning with rare-earth upconversion nanocrystals, single-wavelength near-infrared excitation and portable CCD (charge-coupled device)-based decoding to distinguish particles synthesized by means of flow lithography. This architecture exhibits large, exponentially scalable encoding capacities (>10<SUP>6</SUP> particles), an ultralow decoding false-alarm rate (<10<SUP>−9</SUP>), the ability to manipulate particles by applying magnetic fields, and pronounced insensitivity to both particle chemistry and harsh processing conditions. We demonstrate quantitative agreement between observed and predicted decoding for a range of practical applications with orthogonal requirements, including covert multiparticle barcoding of pharmaceutical packaging (refractive-index matching), multiplexed microRNA detection (biocompatibility) and embedded labelling of high-temperature-cast objects (temperature resistance).
Rapid Light-Driven Color Transition of Novel Photoresponsive Polydiacetylene Molecules
Lee, Jiseok,Seo, Sungbaek,Kim, Jinsang American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.4
<P>We developed new photoresponsive polydiacetylene (PR-PDA) molecules by incorporating a photocleavable moiety, 6-nitropiperonyl alcohol (NP) or 4,5-dimethoxy-2-nitrobenzyl alcohol (DMN), into a self-assembling diacetylene molecule. Inducing steric disordering of the assembled PDA molecules by the cleavage of the photoresponsive moiety under 365 nm UV irradiation results in color transition from blue to red and development of red fluorescence, allowing convenient photo patterning. Further writing and erasing of fluorescence patterns are demonstrated toward novel secure information communication and anticounterfeiting applications.</P>
Lee, Jiseok,Chung, Changuk,Ha, Seungmin,Lee, Dongmin,Kim, Do-Young,Kim, Hyun,Kim, Eunjoon Frontiers Media S.A. 2015 Frontiers in cellular neuroscience Vol.9 No.-
<P>Shank3 is a postsynaptic scaffolding protein implicated in synapse development and autism spectrum disorders. The <I>Shank3</I> gene is known to produce diverse splice variants whose functions have not been fully explored. In the present study, we generated mice lacking <I>Shank3</I> exon 9 (<I>Shank3</I><SUP>Δ<I>9</I></SUP> mice), and thus missing five out of 10 known Shank3 splice variants containing the N-terminal ankyrin repeat region, including the longest splice variant, Shank3a. Our X-gal staining results revealed that Shank3 proteins encoded by exon 9-containing splice variants are abundant in upper cortical layers, striatum, hippocampus, and thalamus, but not in the olfactory bulb or cerebellum, despite the significant Shank3 mRNA levels in these regions. The hippocampal CA1 region of <I>Shank3</I><SUP>Δ<I>9</I></SUP> mice exhibited reduced excitatory transmission at Schaffer collateral synapses and increased frequency of spontaneous inhibitory synaptic events in pyramidal neurons. In contrast, prelimbic layer 2/3 pyramidal neurons in the medial prefrontal cortex displayed decreased frequency of spontaneous inhibitory synaptic events, indicating alterations in the ratio of excitation/inhibition (E/I ratio) in the <I>Shank3</I><SUP>Δ<I>9</I></SUP> brain. These mice displayed a mild increase in rearing in a novel environment and mildly impaired spatial memory, but showed normal social interaction and repetitive behavior. These results suggest that ankyrin repeat-containing Shank3 splice variants are important for E/I balance, rearing behavior, and spatial memory.</P>
Dynamic Multimodal Holograms of Conjugated Organogels via Dithering Mask Lithography
Jiseok Lee(이지석) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1
Complex holographic systems can be dynamically controlled through exposure to external stimuli, yet they usually contain only a single type of holographic mode. Here, we report a conjugated organogel that reversibly displays three modes of holograms in a single architecture. Using dithering mask lithography, we realized two-dimensional patterns with varying cross-linking densities on a conjugated polydiacetylene. In protic solvents, the organogel contracts anisotropically to develop optical and structural heterogeneities along the third dimension, displaying holograms in the form of three-dimensional full parallax signals, both in fluorescence and bright-field microscopy imaging. In aprotic solvents, these heterogeneities diminish as organogels expand, recovering the two-dimensional periodicity to display a third hologram mode based on iridescent structural colours. Our study presents a next-generation hologram manufacturing method for multilevel encryption technologies.
Prediction of Selective Formation of Chair- and Boat-Type Hydrogenated Graphene via Birch Reduction
Lee, Tae Kyung,Lee, Jiseok,Kwak, Sang Kyu American Chemical Society 2019 Chemistry of materials Vol.31 No.12
<P>Practical electronic device applications using graphene-based materials dictate that their band gap must be tunable. The synthesis of hydrogenated graphene has received much attention due to the desirable effect of the gap opening in the electronic band structure. In this study, we present the reaction mechanism of graphene hydrogenation, especially through Birch reduction, and its favorable hydrogenated conformations (chair- and boat-type) on Cu(111). The reduction of graphene was achieved by the graphene π-electron delocalization in the presence of a [Li(NH<SUB>3</SUB>)<SUB>4</SUB><SUP>+</SUP>·<SUP>-</SUP>@(NH<SUB>3</SUB>)<I><SUB>n</SUB></I>] ion-pair. Li<SUP>+</SUP> played an indispensable role in the graphene hydrogenation reaction by facilitating thermodynamically and kinetically favorable reactions when it interacts with the alcohol. For the hydrogenation of graphene on the Cu surface, unlike the freestanding condition, the formation energy revealed that the boat-type was thermodynamically more favorable, and the transfer of unpaired electrons of nonhydrogenated carbon atoms to Cu supports the same prediction. Our findings indicate that this boat-type hydrogenated graphene can be synthesized on Cu(111) through the mechanism of Birch reduction. Also, control of graphene band gaps is achieved by the selective formation of the chair- and boat-type conformations of graphene as self-sustained or on the substrate.</P> [FIG OMISSION]</BR>
Flow around a flexible plate in a free stream
JiSeok Lee,이상환 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.2
This paper presents a numerical scheme for fluid-structure interaction, especially for flexible structures. The lattice Boltzmann method with an immersed boundary technique using a direct forcing scheme is used for the fluid , and a finite element method with Euler beam elements is used for the flexible plate. The direct forcing scheme of the lattice Boltzmann method was improved for the immersed boundary scheme by introducing the occupation ratio of fluid lattices among the interpolated lattices. We compared the results of our proposed scheme with the known results of conventional schemes. Using the proposed numerical scheme, the flow around the flexible plate in a free stream is simulated for the effect of flexibility. Our results show that the major role of the flexibility of the flexible plate is the reduction of the resistance from flow. From the unsteady flow around a flexible plate, we found that the St of the flexible plate up to Re < 80 increased regardless of plate flexibility, but the St in the range of Re > 120 was dependent on plate flexibility. In the range of Re > 120 , the St of very flexible plate increased with increasing Re, while the St of rigid plate decreased with increasing Re .