Research Highlights
Qian-Rui Huang, Ryunosuke Shishido, Chih-Kai Lin, Chen-Wei Tsai, Jake A. Tan, Asuka Fujii* and Jer-Lai Kuo*
Angewandte Chemie International Edition, https://doi.org/10.1002/anie.202012665 (2020).
Experimental infrared spectra between 2600 to 3800 cm-1 for a series of asymmetric proton bound dimers with protonated trimethylamine (TMA–H+) as the proton donor were recorded and analyzed. Based on conventional wisdom, the frequency of the N-H+ stretching mode is expected to red shift as the proton affinity of proton acceptors (Ar, N2, CO, C2H2, H2O, CH3OH, and C2H5OH) increases. The observed band, however, shows a peculiar splitting of ≈300 cm-1 with the intensity shifting pattern resembling a two-level system. Theoretical investigation based on ab initio anharmonic algorithms reveals that the observed band splitting and its extraordinarily large gap of ≈300 cm-1 is a result of strong coupling between fundamental of the proton stretching mode and overtone states of the two proton bending modes, that is commonly known as Fermi resonance (FR). We also provide a simple and general theoretical model to link the strong FR coupling to the quasi-two-level system behavior in the observed band intensity. Since the model does not depend on the molecular specification of TMA–H+, the strong coupling we observed here is an intrinsic property associated with proton motions in a wide range of molecular systems.
Dr. Liang-Yan Hsu, Dr. Chia-Chun Chen
(2020)
Liang-Yan Hsu*, Hung-Chi Yen, Ming-Wei Lee, Yae-Lin Sheu, Po-Chun Chen, Hongjie Dai*, Chia-Chun Chen*
Chem, 2020, 6, 3396-3408.
Large-scale inhomogeneous plasmonic metal chips have been demonstrated as a promisingplatform for biochemical sensing, but the origin of their strong fluorescence enhancementsand average gap dependence is a challenging issue due to the complexity of modelingtremendous molecules within inhomogeneous gaps. To address this issue, we bridgedmicroscopic mechanisms and macroscopic observations, developed a kinetic model, andexperimentally investigated the fluorescence enhancement factors of IR800-streptavidinimmobilized on metal nanoisland films (NIFs). Inspired by the kinetic model, we controlledthe distribution of IR800-streptavidin within the valleys of NIFs by regioselectivemodification and achieved the fluorescence intensity enhancement up to 488-fold. Thekinetic model allows us to qualitatively explain the mechanism of fluorescence intensityenhancements and quantitatively predict the trend of experimental enhancement factors,thereby determining the design principles of the plasmonic metal chips. Our studyprovides one key step further toward the sensing applications of large-scale plasmonicmetal chips.
Dr. Kuei-Hsien Chen
(2020)
Hsiang-Ting Lien, Sun-Tang Chang, Po-Tuan Chen, Deniz P. Wong, Yu-Chung Chang, Ying-Rei Lu, Chung-Li Dong, Chen-Hao Wang, Kuei-Hsien Chen & Li-Chyong Chen
Nature Commmunictions 11, 4233 (2020).
Nonnoble metal catalysts are low-cost alternatives to Pt for the oxygen reduction reactions (ORRs), which have been studied for various applications in electrocatalytic systems. Among them, transition metal complexes, characterized by a redox-active single-metal-atom with biomimetic ligands, such as pyrolyzed cobalt–nitrogen–carbon (Co–N x /C), have attracted considerable attention. Therefore, we reported the ORR mechanism of pyrolyzed Vitamin B12 using operando X-ray absorption spectroscopy coupled with electrochemical impedance spectroscopy, which enables operando monitoring of the oxygen binding site on the metal center. material design strategies for high-performance electrocatalysts for fuel cell applications. Furthermore, the charge transfer mechanism between the catalyst and reactant enables further Co–O species formation. These experimental findings, provide insight into metal active-site geometry and structural evolution during ORR, which could be used for developing material design strategies for high performance electrocatalysts for fuel cell applications.
Dr. Kuei-Hsien Chen
(2020)
Ming-Chiang Chang, Po-Hsun Ho, Mao-Feng Tseng, Fang-Yuan Lin, Cheng-Hung Hou, I-Kuan Lin, Hsin Wang, Pin-Pin Huang, Chun-Hao Chiang, Yueh-Chiang Yang, I-Ta Wang, He-Yun Du, Cheng-Yen Wen, Jing-Jong Shyue, Chun-Wei Chen, Kuei-Hsien Chen, Po-Wen Chiu & Li-Chyong Chen
Nature Commmunictions 11, 3682 (2020).
In this study, a self-capping vaporliquid-solid reaction is proposed to fabricate large-grain, continuous MoS2 films. An intermediate liquid phase-Na2Mo2O7 is formed through a eutectic reaction of MoO3 and NaF,followed by being sulfurized into MoS2. The as-formed MoS2 seeds function as a capping layer that reduces the nucleation density and promotes lateral growth. By tuning the driving force of the reaction, large mono/bilayer (1.1 mm/200 μm) flakes or full-coverage films (with a record-high average grain size of 450 μm) can be grown on centimeter-scale substrates. The field-effect transistors fabricated from the full-coverage films show high mobility (33 and 49 cm2V-1s-1 for the mono and bilayer regions) and on/off ratio (1 ~ 5 × 108) across a 1.5 cm × 1.5 cm region.
Dr. Charles Pin-Kuang Lai
(2020)
Jasper Che-Yung Chien, Elie Tabet, Kelsey Pinkham, Cintia Carla da Hora, Jason Cheng-Yu Chang, Steven Lin, Christian E. Badr* and Charles Pin-Kuang Lai*
Nucleic Acids Research, doi: 10.1093/nar/gkaa669 (2020).
Tracking DNA double strand break (DSB) repair is paramount for the understanding and therapeutic development of various diseases including cancers. Herein, we describe a multiplexed bioluminescent repair reporter (BLRR) for non-invasive monitoring of DSB repair pathways in living cells and animals. The BLRR approach employs secreted Gaussia and Vargula luciferases to simultaneously detect homology-directed repair (HDR) and non-homologous end joining (NHEJ), respectively. BLRR data are consistent with next-generation sequencing results for reporting HDR (R2 = 0.9722) and NHEJ (R2 = 0.919) events. Moreover, BLRR analysis allows longitudinal tracking of HDR and NHEJ activities in cells, and enables detection of DSB repairs in xenografted tumours in vivo. Using the BLRR system, we observed a significant difference in the efficiency of CRISPR/Cas9-mediated editing with guide RNAs only 1–10 bp apart. Moreover, BLRR analysis detected altered dynamics for DSB repair induced by small-molecule modulators. Finally, we discovered HDR-suppressing functions of anticancer cardiac glycosides in human glioblastomas and glioma cancer stem-like cells via inhibition of DNA repair protein RAD51 homolog 1 (RAD51). The BLRR method provides a highly sensitive platform to simultaneously and longitudinally track HDR and NHEJ dynamics that is sufficiently versatile for elucidating the physiology and therapeutic development of DSB repair.
Institute of Atomic and Molecular Sciences Academia Sinica
