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Institution

KAIST

EducationDaejeon, South Korea
About: KAIST is a education organization based out in Daejeon, South Korea. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 35562 authors who have published 77661 publications receiving 1852854 citations. The organization is also known as: Korea Advanced Institute of Science and Technology & KAIST university.


Papers
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Journal ArticleDOI
Kwanghun Kim1, Sang-Joon Kim1, Hee-Jin Cho1, Namhoon Kim1, Ji-Soo Jang1, Seon-Jin Choi1, Il-Doo Kim1 
TL;DR: In this paper, a novel catalytic synthesis and functionalization method using apoferritin is used to fabricate RuO2 nanoparticles (NPs) loaded WO3 nanofibers (NFs) for potential diagnosis of diabetes.
Abstract: In this work, a novel catalytic synthesis and functionalization method using apoferritin is used to fabricate RuO2 nanoparticles (NPs) loaded WO3 nanofibers (NFs) for potential diagnosis of diabetes. Catalytic ruthenium (Ru) NPs with very small average diameters of 1.8 ± 0.9 nm were synthesized using apoferritin which is a hollow protein cage, and were easily functionalized on WO3 NFs by introducing electrospinning solution with W precursor and polyvinylpyrrolidone (PVP). As-spun Ru NPs-loaded W precursor/PVP composite NFs were calcined at 600 °C for 1 h in air atmosphere to achieve RuO2-functionalized WO3 NFs. The small size and uniform distribution of catalytic RuO2 NPs were well maintained due to hollow nature of apoferritin cages after calcination. The chemo-resistive sensors using RuO2-functionalized WO3 NFs showed significantly enhanced acetone (CH3COCH3) sensing response (Rair/Rgas = 78.61–5 ppm), which was 7.4 times higher than the response (Rair/Rgas = 10.61–5 ppm) of pristine WO3 NFs at highly humid atmosphere (95% RH). In addition, the RuO2-functionalized WO3 NFs showed outstanding selectivity toward acetone gas in comparison with other gases such as hydrogen sulfide (H2S), toluene (C6H5CH3), ethanol (C2H5OH), pentane (C5H12), ammonia (NH3), hydrogen (H2), and water vapor (H2O) at 5 ppm. These results represent potential feasibility for the detection of acetone in exhaled breath for diagnosis of diabetes.

52 citations

Journal ArticleDOI
TL;DR: A sensitive and selective assay of uracil DNA glycosylase (UDG) activity is developed by utilizing a G- quadruplex probe incorporating 2-aminopurine (2-AP), based on a novel design that excision reaction promoted by UDG triggers the formation of G-quadruplex structure with significant fluorescence enhancement of 2-AP within the probe.

52 citations

Journal ArticleDOI
TL;DR: Kim et al. as discussed by the authors reported the global dynamics of the photodissociation of iodoform in methanol and showed that the formation of the isomer is not a major reaction channel in the investigated time range, that is, from 100 ps to 3 ms.
Abstract: The understanding of reaction mechanisms requires detailed information about the processes that take place during the reactions. Various time-resolved optical spectroscopic tools have been developed to track such processes, and reaction dynamics can now be routinely investigated, with a time resolution of tens of femtoseconds, by using these optical techniques. Typical information provided by timeresolved spectroscopy includes the time constants of reaction intermediates and limited structural information. In most cases, however, detailed structural information, such as the bond lengths and angles in reaction intermediates, are extremely difficult to obtain from time-resolved optical spectroscopy (except for a few favorable cases in which they can be deduced from time-resolved vibrational spectroscopy and multi-dimensional spectroscopy measurements). Replacing the optical probe pulses in time-resolved spectroscopy measurements with either electron or Xray pulses converts the optical resonances in energy space into atomic interferences in real space, which offers a complementary—and more direct—way to investigate the structural dynamics of molecular reactions. Because of the relatively low penetration depth of electrons, X-rays are more suitable for probing crystalline and liquid samples; for example, all the atoms in a protein can be tracked during its biological function by means of timeresolved X-ray crystallography, but to do so it is necessary to produce single protein crystals. This limitation has been recently overcome by introducing transient X-ray liquidography (TXL), a method through which the transient molecular structures present in a liquid sample can be captured in one dimension by performing time-resolved Xray diffraction measurements in the liquid phase. TXL is a new technique that can be used to investigate reactions in solution, where most of the chemically and biologically relevant processes take place. Since the diffraction patterns generated by the short X-ray pulses arriving at the sample after laser excitation include all the molecular structures present in the irradiated volume, the analysis of TXL data can reveal the structural evolution of all the reaction pathways in the sample (limited only by the signal-to-noise ratio of the diffracted difference signal). We recently succeeded in studying the structural reaction dynamics of several molecules in solution by using this method. The photochemistry of iodoform (CHI3) has received considerable attention because of the suggested formation of a unique intermediate, called isoiodoform (CHI2 I), which has been studied by using several time-resolved spectroscopic methods, such as transient absorption and transient resonance Raman spectroscopies. According to these studies, a parent iodoform molecule loses an iodine atom upon photoexcitation at 267 nm. The CHI2 radical and the I atom then recombine geminately to form isoiodoform within the solvent cage; this is a common reaction in diand trihaloalkanes. Previous studies suggest that isoiodoform is the major intermediate, with a lifetime of several microseconds. We note that optical spectroscopy can be highly sensitive to a particular species, but sometimes this advantage translates into biased or nonglobal sampling, that is, certain intermediates might be optically “silent” and escape detection. In contrast, the diffraction signal contains scattering information from all the atoms in the sample, thus providing a global picture of the reactions—although at the expense of sensitivity. Herein we report the global dynamics of the photodissociation of iodoform in methanol and show that the formation of the isomer is not a major reaction channel in the investigated time range, that is, from 100 ps to 3 ms. Time-resolved diffraction data were collected on the pump–probe beamline ID09B at the European Synchrotron Radiation Facility (ESRF) at time delays of 3 ns; 100, 100, and 300 ps; 1, 3, 6, 10, 30, 45, 60, 300, and 600 ns; and 1 and 3 ms. The diffraction signal corresponding the structural change is quite weak (about 0.1%) relative to the total diffraction signal. To extract the structural changes only, a non-excited reference data (at 3 ns) is subtracted from the diffraction data obtained at positive time delays. To magnify the scattered intensities at high angles (at which the signal becomes weak as a result of the decay in the atomic form factors), the change in the diffracted intensity, DS(q), is multiplied by q= (4p/l)sin(q/2), where l is the X-ray wave[*] J. H. Lee, J. Kim, K. H. Kim, Dr. J. Choi, Prof. H. Ihee Center for Time-Resolved Diffraction Department of Chemistry (BK21) Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305–701 (Republic of Korea) Fax: (+82)42-869-2810 E-mail: hyotcherl.ihee@kaist.ac.kr Homepage: http://time.kaist.ac.kr

52 citations

Journal ArticleDOI
TL;DR: This study derives the reverse link capacity of an SIR-based power control system supporting ON-off traffic in a multiple cell environment and two different power control systems are compared in terms of capacity in both CBR and ON-OFF traffic environments.
Abstract: Capacity estimation in code division multiple access (CDMA) systems is an important issue which is closely related to power control. Many previous studies assumed strength-based power control, which maintains received power at a desired level regardless of changes in the number of active users and in the amount of total other cell interference. However, in signal-to-interference ratio (SIR)-based power control systems, which maintain the received SIR at a desired level, the power level is a function of the above two variables. This study derives the reverse link capacity of an SIR-based power control system supporting ON-OFF traffic in a multiple cell environment. Two different power control systems are compared in terms of capacity in both CBR and ON-OFF traffic environments. The effects of activity factor, the required E/sub b//I/sub o/, the maximum received power, and propagation parameters are also investigated.

52 citations

Journal ArticleDOI
TL;DR: This work reports a novel PDZ interaction between the CAZ protein ERC2/CAST1 and the tandem PDZ protein syntenin-1, which is known to associate with diverse synaptic proteins, including glutamate receptor subunits, SynCAM, and β-neurexin.
Abstract: Presynaptic active zones contain a cytoskeletal matrix called the CAZ, which is thought to play a critical role in the regulation of active zone formation and neurotransmitter release Recent studies have identified several CAZ components, but little is known about how they contribute to the molecular organization of active zones Here, we report a novel PDZ [postsynaptic density-95/Discs large/zona occludens-1] interaction between the CAZ protein ERC2/CAST1 and the tandem PDZ protein syntenin-1, which is known to associate with diverse synaptic proteins, including glutamate receptor subunits, SynCAM, and β-neurexin This interaction promotes the localization of syntenin-1 at presynaptic ERC2 clusters In addition to the PDZ interaction, multimerization of both ERC2 and syntenin-1 mediates syntenin-1 clustering These results suggest that ERC2 promotes presynaptic syntenin-1 clustering by two distinct mechanisms and that syntenin-1 may contribute to the molecular organization of active zones by linking ERC2 and other CAZ components to diverse syntenin-1-associated synaptic proteins

52 citations


Authors

Showing all 35844 results

NameH-indexPapersCitations
Robert Langer2812324326306
Yi Cui2201015199725
Hyun-Chul Kim1764076183227
Kari Alitalo174817114231
Yury Gogotsi171956144520
Omar M. Yaghi165459163918
Hannes Jung1592069125069
Yongsun Kim1562588145619
Xiang Zhang1541733117576
William A. Goddard1511653123322
Jongmin Lee1502257134772
J. Fraser Stoddart147123996083
Bernhard O. Palsson14783185051
A. Paul Alivisatos146470101741
Taeghwan Hyeon13956375814
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023108
2022480
20214,169
20204,412
20194,204
20183,988