Ultrasensitive, Low-Power Oxide Transistor-Based Mechanotransducer with Microstructured, Deformable Ionic Dielectrics

Jang, Sukjin,Jee, Eunsong,Choi, Daehwan,Kim, Wook,Kim, Joo Sung,Amoli, Vipin,Sung, Taehoon,Choi, Dukhyun,Kim, Do Hwan,Kwon, Jang-Yeon American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.37

<P>The development of a highly sensitive artificial mechanotransducer that mimics the tactile sensing features of human skin has been a big challenge in electronic skin research. Here, we demonstrate an ultrasensitive, low-power oxide transistor-based mechanotransducer modulated by microstructured, deformable ionic dielectrics, which is consistently sensitive to a wide range of pressures from 1 to 50 kPa. To this end, we designed a viscoporoelastic and ionic thermoplastic polyurethane (i-TPU) with micropyramidal feature as a pressure-sensitive gate dielectric for the indium-gallium-zinc-oxide (IGZO) transistor-based mechanotransducer, which leads to an unprecedented sensitivity of 43.6 kPa<SUP>-1</SUP>, which is 23 times higher than that of a capacitive mechanotransducer. This is because the pressure-induced ion accumulation at the interface of the i-TPU dielectric and IGZO semiconductor effectively modulates the conducting channel, which contributed to the enhanced current level under pressure. We believe that the ionic transistor-type mechanotransducer suggested by us will be an effective way to perceive external tactile stimuli over a wide pressure range even under low power (<4 V), which might be one of the candidates to directly emulate the tactile sensing capability of human skin.</P> [FIG OMISSION]</BR>

Microsurgical treatment of distal middle cerebral artery aneurysm: A single-center review

Taehoon Jang,Sung-Tae Kim,Jin Lee,Won Hee Lee,Keun-Soo Lee,Se Young Pyo,Junghae Ko,Hangwoo Lee,Yeong Gyun Jeong 대한뇌혈관외과학회 2024 Journal of Cerebrovascular and Endovascular Neuros Vol.26 No.1

Objective: To review the characteristics of distal middle cerebral artery (MCA) aneurysm treated by microsurgery, the detailed surgical options, and the clinical result.Methods: We retrospectively reviewed cerebral aneurysm in the M2 and M3 segments of the MCA surgically treated between January 2015 and December 2022. The demographic data, aneurysm-related findings, type of surgical approach, surgical technique, and clinical outcomes of the enrolled patients were analyzed.Results: Sixteen distal MCA aneurysms were treated with microneurosurgery (incidence, 1.0%; female, 12; mean age, 58.1 years; ruptured, three). Twelve aneurysms were in the M2 segment (insular segment), two aneurysms at the M2–M3 junction, and two aneurysms in the M3 segment (opercular segment). Twelve aneurysms were saccular (average size, 4.9 mm; multiplicity, 50%; average aneurysms, 3.0; partially thrombosed, 1; sidewall aneurysm, 2). Three aneurysms were fusiform, of which two were ruptured. Of the ruptured aneurysms, one was a ruptured dissecting aneurysm. The trans-sylvian and trans-sulcal approaches were used in fourteen and two patients, respectively. Neck clipping, wrap clipping, and surgical trapping were performed in twelve, one, and one patient, respectively. Proximal occlusion was performed in one patient. Bypass technique was required in two patients (neck clipping and proximal occlusion). The modified Rankin Score was 6 in the two patients with ruptured aneurysms. The remaining patients did not show further neurological deterioration after microneurosurgery.Conclusions: Distal MCA aneurysms had a high incidence of being diagnosed with multiple other aneurysms and were relatively non-saccular.

상용화 관점에서 바라본 GaN 전력반도체 기술

장태훈(Taehoon Jang) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.11

Patterns in renal diseases diagnosed by kidney biopsy: A single-center experience

( Taehoon Yim ),( Sang-un Kim ),( Sangmi Park ),( Jeong-hoon Lim ),( Hee-yeon Jung ),( Jang-hee Cho ),( Chan-duck Kim ),( Yong-lim Kim ),( Man-hoon Han ),( Yong-jin Kim ),( Ji-young Choi ),( Sun-hee P 대한신장학회 2020 Kidney Research and Clinical Practice Vol.39 No.1

Background: The worldwide incidence of renal disease diagnosed by a kidney biopsy varies with age, race, sex, and region. Owing to a lack of studies and limited research resources for this disease in Korea, we investigated renal disease patterns by analyzing data from kidney biopsies performed over 13 years in a university-based teaching hospital in Korea. Methods: Among 2,053 kidney biopsies performed from 2001 to 2013 at Kyungpook National University Hospital, 1,924 were retrospectively analyzed for histopathologic, demographic, and clinical data as well as laboratory results. Results: Among the 1,924 studied kidney biopsies, 1,078 were males (56.0%) and the mean age was 37.7 ± 16.5 years. Asymptomatic urinary abnormalities were the most common clinical manifestation (62.5%). Immunoglobulin A nephropathy (IgAN) was the most common primary glomerular disease (37.4%), followed by minimal change disease (MCD), membranous nephropathy (MN), focal segmental glomerulonephritis and crescentic glomerulonephritis. Secondary glomerular diseases accounted for 10.3% of the total biopsies, with lupus nephritis being the most common (4.6%) followed by Henoch-Schönlein purpura nephritis and diabetic nephropathy. The most common cause of nephrotic syndrome was MCD (42.1%) followed by MN. Among patients seropositive for hepatitis B or C, IgAN (28.3% and 21.4%, respectively) was the most common cause. Conclusion: IgAN and lupus nephritis were the most common primary and secondary glomerular diseases, respectively. Race, region, and practice patterns may affect renal disease patterns in different cohorts.

Preparation and characterization of sulfonated poly(phenylene)s membranes containing conjugated moiety via nickel catalyzed carbon–carbon coupling polymerization

Jang, Hohyoun,Hong, Taehoon,Yoo, Jiho,Lee, Soonho,Pyo, Jaeseung,Sutradhar, Sabuj Chandra,Ju, Hyunchul,Kim, Whangi Elsevier 2015 International journal of hydrogen energy Vol.40 No.41

<P><B>Abstract</B></P> <P>A series of sulfonated polyphenylene membranes (SPBCDPEs) containing conjugated tetraphenylethylene moieties were synthesized via Ni(0) catalyzed polymerization, and subsequent sulfonation with concentrated sulfuric acid. These membranes showed improved performance in ion exchange capacity, water uptake, proton conductivity, and thermal stability over Nafion 211<SUP>®</SUP> membranes. The membranes' thermal properties were investigated by thermo-gravimetric analysis (TGA) and also surface morphologies were assessed by atomic force microscope (AFM). SPBCDPEs may have applications as fuel cell membranes due to excellent proton conductivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We synthesized sulfonated polyphenylene containing conjugated structure. </LI> <LI> We controlled the degree of sulfonation by BCDPE monomer. </LI> <LI> Increasing sulfonation level increases proton conductivity. </LI> <LI> Membranes showed good performance with high proton conductivity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Sulfonated carbon–carbon structured copolymers (SPBCDPEs) are described: A series of sulfonated polyphenylene membranes (SPBCDPEs) containing conjugated tetraphenylethylene moieties were synthesized via Ni(0) catalyzed polymerization, and subsequent sulfonation with concentrated sulfuric acid. The proposed polymer membranes, without ether linkages, demonstrated good chemical stability, proton conductivity, and solubility in aprotic organic solvents.</P> <P>[DISPLAY OMISSION]</P>

공간 정보 처리에 특화된 공간 데이터 ETL을 위한 NiFi Custom Processor 설계에 관한 연구

Taehoon Kim,Wangro Lee,Kyungsu Jang 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6

Self-activated Graphene Gas Sensors: A Mini Review

( Taehoon Kim ),( Tae Hoon Eom ),( Ho Won Jang ) 한국센서학회 2020 센서학회지 Vol.29 No.4

Graphene has been widely considered a promising candidate for high-quality chemical sensors, owing to its outstanding characteristics, such as sensitive gas adsorption at room temperature, high conductivity, high flexibility, and high transparency. However, the main drawback of a graphene-based gas sensor is the necessity for external heaters due to its slow response, incomplete recovery, and low selectivity at room temperature. Conventional heating devices have limitations such as large volume, thermal safety issues, and high power consumption. Moreover, metal-based heating systems cannot be applied to transparent and flexible devices. Thus, to solve this problem, a method of supplying the thermal energy necessary for gas sensing via the self-heating of graphene by utilizing its high carrier mobility has been studied. Herein, we provide a brief review of recent studies on self-activated graphene-based gas sensors. This review also describes various strategies for the self-activation of graphene sensors and the enhancement of their sensing properties.

An Enhanced Random Access Scheme With Spatial Group Based Reusable Preamble Allocation in Cellular M2M Networks

Taehoon Kim,Han Seung Jang,Dan Keun Sung IEEE 2015 IEEE communications letters Vol.19 No.10

<P>In the near future, cellular machine-to-machine (M2M) communications are expected to play an important role to realize the Internet of Things (IoT). Due to the exponentially growing number of machine nodes, however, one of challenging issues is to accommodate their random access (RA) requests without severely degrading the performance of human-to-human (H2H) communications. In this letter, we propose an enhanced RA scheme with spatial group based reusable preamble allocation (ERA-SGRPA), which reuses the preamble resources based on a spatial grouping during the RA procedure. By allocating the identical preamble set to the groups which are far apart from each other, the ERA-SGRPA scheme enables the given preamble set to be efficiently reused. The performance evaluation shows that the ERA-SGRPA scheme significantly lowers the collision probability and reduces the access delay and can accommodate a significantly larger number of machine nodes without degrading the performance of H2H communications.</P>

Styrenic block copolymer/sulfonated graphene oxide composite membranes for highly bendable ionic polymer actuators with large ion concentration gradient

Lee, Jang-Woo,Kwon, Taehoon,Kang, Youngjong,Han, Tae Hee,Cho, Chang Gi,Hong, Soon Man,Hwang, Suk-Won,Koo, Chong Min Elsevier 2018 Composites science and technology Vol.163 No.-

<P>In this study, sulfonated graphene oxide (sGO) with a large enhanced sulfonation degree of 1.65 mmol g(-1) was simultaneously introduced as a highly ion conduction-activating carbonaceous filler for ionic polymer-metal composite (IPMC) actuator. The nanostructured styrenic block copolymer/sGO/ionic liquid (IL) composite membrane actuators revealed much larger actuation performance than top-ranked polyelectrolyte/IL actuators ever reported so far in terms of bending strain (0.88% under 2 V dc), initial strain rate (0.312% min(-1)), and charge-specific displacement (276.4 mm C-1). Moreover, SSPB/sGO/IL actuators exhibited excellent actuation performance without drawbacks of conventional IPMCs, such as back-relaxation and early loss of inner solvent. In addition, via tracking the movement of the IL's anion through energy-dispersive X-ray spectroscopy (EDS) analysis, not only the transporting behaviour of IL but also the pumping effect with solvated ion complexes inside the actuator are confirmed for the first time.</P>

Oral Administration of (S)-Allyl-l-Cysteine and Aged Garlic Extract to Rats: Determination of Metabolites and Their Pharmacokinetics

Park, Taehoon,Oh, Ju-Hee,Lee, Joo Hyun,Park, Sang,Jang, Young,Lee, Young-Joo Georg Thieme Verlag KG 2017 Planta medica Vol.83 No.17

<B>Abstract</B><P>(S)-Allyl-l-cysteine is the major bioactive compound in garlic. (S)-Allyl-l-cysteine is metabolized to (S)-allyl-l-cysteine sulfoxide, N-acetyl-(S)-allyl-l-cysteine, and N-acetyl-(S)-allyl-l-cysteine sulfoxide after oral administration. An accurate LC-MS/MS method was developed and validated for the simultaneous quantification of (S)-allyl-l-cysteine and its metabolites in rat plasma, and the feasibility of using it in pharmacokinetic studies was tested. The analytes were quantified by multiple reaction monitoring using an atmospheric pressure ionization mass spectrometer. Because significant quantitative interference was observed between (S)-allyl-l-cysteine and N-acetyl-(S)-allyl-l-cysteine as a result of the decomposition of N-acetyl-(S)-allyl-l-cysteine at the detector source, chromatographic separation was required to discriminate (S)-allyl-l-cysteine and its metabolites on a reversed-phase C18 analytical column with a gradient mobile phase consisting of 0.1% formic acid and acetonitrile. The calibration curves of (S)-allyl-l-cysteine, (S)-allyl-l-cysteine sulfoxide, N-acetyl-(S)-allyl-l-cysteine, and N-acetyl-(S)-allyl-l-cysteine sulfoxide were linear over each concentration range, and the lower limits of quantification were 0.1 µg/mL [(S)-allyl-l-cysteine and N-acetyl-(S)-allyl-l-cysteine] and 0.25 µg/mL [(S)-allyl-l-cysteine sulfoxide and N-acetyl-(S)-allyl-l-cysteine sulfoxide]. Acceptable intraday and inter-day precisions and accuracies were obtained at three concentration levels. The method satisfied the regulatory requirements for matrix effects, recovery, and stability. The validated LC-MS/MS method was successfully used to determine the concentration of (S)-allyl-l-cysteine and its metabolites in rat plasma samples after the administration of (S)-allyl-l-cysteine or aged garlic extract.</P>