Identification of the novel HLA-B*58:138 allele in a Korean individual.

HLA-B*58:138 differs from HLA-B*58:01:01:01 by one nucleotide substitution in exon 3 at codon 145.

Factors Affecting Participation in Telerehabilitation Using Transcranial Direct Current Stimulation for Patients with Poststroke Paralysis in South Korea.

Background: The coronavirus disease 2019 pandemic has expanded noncontact health care systems worldwide. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technology that enables treatment monitoring under remote supervision. We investigated the factors affecting patients' decision to participate in telerehabilitation (TR) using tDCS for motor function recovery after suffering a stroke. Materials and Methods: Four medical institutions surveyed 156 patients with poststroke paralysis. The participants were asked whether they would participate in TR therapy using tDCS in the future. We performed logistic regression analysis to examine the factors-demographic data, stroke characteristics, arm function, gait, and cognitive function-that influenced participants' decisions. Results: Of the participants, 66% (103/156) reported that they would participate in TR using tDCS in the future. Participants' monthly salary was a single significant independent factor influencing their decision to participate. Those earning greater than 5 million KRW (4,000 USD) were more likely to engage in TR via tDCS than those earning less than 1 million KRW (800 USD). The most common barriers to participation in telemedicine included the preference for face-to-face treatment and unfamiliarity. The expected medical expenses of TR using tDCS were 46,154 KRW (37 USD) per session. Conclusions: Most participants with poststroke paralysis responded positively to TR using tDCS for hand function recovery. For telemedicine to work effectively in a situation wherein face-to-face rehabilitation is impossible, prior discussion at the governmental level is essential for determining medical finances.

Effect of Precursor Status on the Transition from Complex to Carbon Shell in a Platinum Core-Carbon Shell Catalyst.

Encapsulating platinum nanoparticles with a carbon shell can increase the stability of core platinum nanoparticles by preventing their dissolution and agglomeration. In this study, the synthesis mechanism of a platinum core-carbon shell catalyst via thermal reduction of a platinum-aniline complex was investigated to determine how the carbon shell forms and identify the key factor determining the properties of the Pt core-carbon shell catalyst. Three catalysts originating from the complexes with different platinum to carbon precursor ratios were synthesized through pyrolysis. Their structural characteristics were examined using various analysis techniques, and their electrochemical activity and stability were evaluated through half-cell and unit-cell tests. The relationship between the nitrogen to platinum ratio and structural characteristics was revealed, and the effects on the electrochemical activity and stability were discussed. The ratio of the carbon precursor to platinum was the decisive factor determining the properties of the platinum core-carbon shell catalyst.

Nafion Composite Membranes Impregnated with Polydopamine and Poly(Sulfonated Dopamine) for High-Performance Proton Exchange Membranes.

We prepared Nafion composite membranes by impregnating Nafion-212 with polydopamine, poly(sulfonated dopamine), and poly(dopamine-co-sulfonated dopamine) using the swelling-filling method to generate nanopores in the Nafion framework that were filled with these polymers. Compared to the pristine Nafion-212 membrane, these composite membranes showed improved thermal and mechanical stabilities due to the strong interactions between the catecholamine of the polydopamine derivatives and the Nafion matrix. For the composite membrane filled with poly(sulfonated dopamine) (N-PSDA), further interactions were induced between the Nafion and the sulfonic acid side chain, resulting in enhanced water uptake and ion conductivity. In addition, filling the nanopores in the Nafion matrix with polymer fillers containing aromatic hydrocarbon-based dopamine units led to an increase in the degree of crystallinity and resulted in a significant decrease in the hydrogen permeability of the composite membranes compared to Nafion-212. Hydrogen crossovers 26.8% lower than Nafion-212 at 95% relative humidity (RH) (fuel cell operating conditions) and 27.3% lower at 100% RH (water electrolysis operating conditions) were obtained. When applied to proton exchange membrane-based fuel cells, N-PSDA exhibited a peak power density of 966 mW cm-2, whereas N-PSDA showed a current density of 4785 mA cm-2, which is 12.4% higher than Nafion-212 at 2.0 V and 80 °C.

The novel HLA-C*06:325 allele identified in a Korean individual awaiting kidney transplantation.

HLA-C*06:325 differs from HLA-C*06:02:01:01 by a non-synonymous nucleotide substitution in codon 145, changing Arginine to Histidine.

A new allele, HLA-C*08:228, identified by sequence-based typing in a Korean individual.

The new allele C*08:228 showed one nucleotide difference from C*08:01:01 in codon 36 (TTC -> TTG).

Investigation on the Microscopic/Macroscopic Mechanical Properties of a Thermally Annealed Nafion® Membrane.

The Nafion® electrolyte membrane, which provides a proton pathway, is an essential element in fuel cell systems. Thermal treatment without additional additives is widely used to modify the mechanical properties of the membrane, to construct reliable and durable electrolyte membranes in the fuel cell. We measured the microscopic mechanical properties of thermally annealed membranes using atomic force microscopy with the two-point method. Furthermore, the macroscopic property was investigated through tensile tests. The microscopic modulus exceeded the macroscopic modulus over all annealing temperature ranges. Additionally, the measured microscopic modulus increased rapidly near 150 °C and was saturated over that temperature, whereas the macroscopic modulus continuously increased until 250 °C. This mismatched micro/macroscopic reinforcement trend indicates that the internal reinforcement of the clusters is induced first until 150 °C. In contrast, the reinforcement among the clusters, which requires more thermal energy, probably progresses even at a temperature of 250 °C. The results showed that the annealing process is effective for the surface smoothing and leveling of the Nafion® membrane until 200 °C.

Differences in the Electrochemical Performance of Pt-Based Catalysts Used for Polymer Electrolyte Membrane Fuel Cells in Liquid Half- and Full-Cells.

A substantial amount of research effort has been directed toward the development of Pt-based catalysts with higher performance and durability than conventional polycrystalline Pt nanoparticles to achieve high-power and innovative energy conversion systems. Currently, attention has been paid toward expanding the electrochemically active surface area (ECSA) of catalysts and increase their intrinsic activity in the oxygen reduction reaction (ORR). However, despite innumerable efforts having been carried out to explore this possibility, most of these achievements have focused on the rotating disk electrode (RDE) in half-cells, and relatively few results have been adaptable to membrane electrode assemblies (MEAs) in full-cells, which is the actual operating condition of fuel cells. Thus, it is uncertain whether these advanced catalysts can be used as a substitute in practical fuel cell applications, and an improvement in the catalytic performance in real-life fuel cells is still necessary. Therefore, from a more practical and industrial point of view, the goal of this review is to compare the ORR catalyst performance and durability in half- and full-cells, providing a differentiated approach to the durability concerns in half- and full-cells, and share new perspectives for strategic designs used to induce additional performance in full-cell devices.

The novel HLA-DQB1 allele, HLA-DQB1*03:457, identified in a Korean kidney transplant recipient.

HLA-DQB1*03:457 differs from HLA-DQB1*03:02:01:01 by a non-synonymous nucleotide substitution in codon 95, changing valine to glutamic acid.

Nafion-Based Proton-Exchange Membranes Built on Cross-Linked Semi-Interpenetrating Polymer Networks between Poly(acrylic acid) and Poly(vinyl alcohol).

We report semi-interpenetrating polymer network (semi-IPN) membranes prepared easily from a cross-linked network using poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA) with interpenetrated Nafion for both proton-exchange membrane fuel cell (PEMFC) and proton-exchange membrane water electrolyzer (PEMWE) applications. Thermal esterification between PAA and PVA induced three-dimensional cross-linking to improve mechanical toughness and reduce hydrogen crossover, while the hydrophilic nature of the PAA-PVA-based cross-linked matrix still enhanced the water uptake (WU) and hence conductivity of the Nafion penetrant. The semi-IPN membrane (NPP-95) composed of Nafion, PAA, and PVA with a ratio of 95:2.5:2.5 showed a hexagonal cylindrical morphology and improved thermal, mechanical, and dimensional stability compared to a recast Nafion membrane (re-Nafion). The membrane was also highly effective at managing water due to its low WU and high conductivity. Furthermore, its hydrogen permeability was 49.6% lower than that of re-Nafion under the actual fuel cell operating conditions (at 100% RH and 80 °C). NPP-95 exhibited significantly improved conductivity and PEMFC performance compared to re-Nafion with a current density of 1561 mA/cm2 at a potential of 0.6 V and a peak power density of 1179 mW/cm2. Furthermore, in the PEMWE performances, NPP-95 displayed about a 1.5-fold higher current density of 4310 mA/cm2 at 2.0 V and much lower ohmic resistance than re-Nafion between 60 and 80 °C.

The HLA-C*03:539 allele identified in a kidney transplantation recipient.

The novel HLA-C*03:539 allele differs from HLA-C*03:04:01:01 by one nucleotide substitution at codon 26.

Methanol Tolerant Pt-C Core-Shell Cathode Catalyst for Direct Methanol Fuel Cells.

Methanol crossover is one of the largest problems in direct methanol fuel cells (DMFCs). Methanol passing from the anode to the cathode through the membrane is oxidized at the cathode, degrading the DMFC performance, and the intermediates of the methanol oxidation reaction (MOR) cause cathode catalyst poisoning. Therefore, it is essential to develop a cathode catalyst capable of inhibiting MOR while promoting the oxygen reduction reaction (ORR), which is a typical cathode reaction in DMFCs. In this study, a carbon-encapsulated Pt cathode catalyst was synthesized for this purpose. The catalyst was simply synthesized by heat treatment of Pt-aniline complex-coated carbon nanofibers. The carbon shell of the catalyst was effective in inhibiting methanol from accessing the Pt core, and this effect became more prominent as the graphitization degree of the carbon shell increased. Meanwhile, the carbon shell allowed O2 to permeate regardless of the graphitization degree, enabling the Pt core to participate in ORR. The synthesized catalyst showed higher performance and stability in single-cell tests under various conditions compared to commercial Pt/C.

Confirmation of the recently described HLA-DPA1 allele, HLA-DPA1*02:02:08.

The HLA-DPA1*02:02:08 allele differs from HLA-DPA1*02:02:02:01 by a synonymous nucleotide substitution at codon 194.

A nitrogen and fluorine enriched Fe/Fe3C@C oxygen reduction reaction electrocatalyst for anion/proton exchange membrane fuel cells.

Nitrogen-doped carbon-encapsulated non-noble metals are promising electrocatalytic alternatives to Pt for the oxygen reduction reaction (ORR). Herein, we describe the efficient synthesis of nitrogen- and fluorine-doped carbon-encapsulated Fe/Fe3C (NFC@Fe/Fe3C) crystals from a Fe-poly(aniline-fluoro-aniline) co-polymer and demonstrate their use as efficient ORR electrocatalysts in acidic and alkaline environments. X-ray diffraction patterns, scanning electron microscopy, transmission electron microscopy, Raman spectra, and X-ray photoelectron spectroscopy are used to determine the structural properties of NFC@Fe/Fe3C. Of the NFC@Fe/Fe3C catalysts, NFC@Fe/Fe3C-9 demonstrates superior ORR electrocatalytic activity in both alkaline and acidic environments. NFC@Fe/Fe3C-9 follows a four-electron-transfer ORR pathway in alkaline and acidic media. Under alkaline conditions, NFC@Fe/Fe3C-9 displays a half-wave potential (E1/2) as 0.870 V, which is 16 mV higher than that of Pt/C, and its durability decay is 26 mV over 50 000 cycles. In acidic medium, the NFC@Fe/Fe3C-9 electrode shows inferior ORR performance than does Pt/C, but it is more durable, with only 27 mV decay over 30 000 cycles. A single cell performance of NFC@Fe/Fe3C-9 was tested with a proton-exchange membrane fuel cells (PEMFC) and an anion-exchange membrane fuel cell (AEMFC) with an active area of 5 cm2. The PEMFC single cell exhibits the maximum power density of 237 mW cm-2 with a back pressure of 250 kPa, while the AEMFC delivers a maximum power density of 96 mW cm-2 without back pressure.

Identification of the novel HLA-B allele, HLA-B*27:198, from a Korean individual.

The novel HLA-B*27:198 allele differs from HLA-B*27:05:02:01 by one nucleotide substitution at codon 45.

Ultrafine Pt Nanoparticles Stabilized by MoS2/N-Doped Reduced Graphene Oxide as a Durable Electrocatalyst for Alcohol Oxidation and Oxygen Reduction Reactions.

Direct alcohol fuel cells play a pivotal role in the synthesis of catalysts because of their low cost, high catalytic activity, and long durability in half-cell reactions, which include anode (alcohol oxidation) and cathode (oxygen reduction) reactions. However, platinum catalysts suffer from CO tolerance, which affects their stability. The present study focuses on ultrafine Pt nanoparticles stabilized by flowerlike MoS2/N-doped reduced graphene oxide (Pt@MoS2/NrGO) architecture, developed via a facile and cost-competitive approach that was performed through the hydrothermal method followed by the wet-reflux strategy. Fourier transform infrared spectra, X-ray diffraction patterns, Raman spectra, X-ray photoelectron spectra, field-emission scanning electron microscopy, and transmission electron microscopy verified the conversion to Pt@MoS2/NrGO. Pt@MoS2/NrGO was applied as a potential electrocatalyst toward the anode reaction (liquid fuel oxidation) and the cathode reaction (oxygen reduction). In the anode reaction, Pt@MoS2/NrGO showed superior activity toward electro-oxidation of methanol, ethylene glycol, and glycerol with mass activities of 448.0, 158.0, and 147.0 mA/mgPt, respectively, approximately 4.14, 2.82, and 3.34 times that of a commercial Pt-C (20%) catalyst. The durability of the Pt@MoS2/NrGO catalyst was tested via 500 potential cycles, demonstrating less than 20% of catalytic activity loss for alcohol fuels. In the cathode reaction, oxygen reduction reaction results showed excellent catalytic activity with higher half-wave potential at 0.895 V versus a reversible hydrogen electrode for Pt@MoS2/NrGO. The durability of the Pt@MoS2/NrGO catalyst was tested via 30 000 potential cycles and showed only 15 mV reduction in the half-wave potential, whereas the Pt@NrGO and Pt-C catalysts experienced a much greater shift (Pt@NrGO, ∼23 mV; Pt-C, ∼20 mV).

Dual-Functional Electrocatalyst Derived from Iron-Porphyrin-Encapsulated Metal-Organic Frameworks.

Active, stable electrocatalysts based on non-precious metals for the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) are critical for the development of cost-effective, efficient renewable energy technologies. Here, Fe/Fe3C-embedded nitrogen-doped carbon was fabricated via pyrolysis of iron-porphyrin-encapsulated mesoporous metal-organic frameworks [PCN-333 (Fe), where "PCN" stands for "porous coordination network"] at 700 °C. The various characterization techniques confirmed that Fe- and Fe3C-containing Fe-N-C material (FeP-P333-700) was successfully prepared by pyrolysis of porphyrin-encapsulated PCN-333 (Fe). FeP-P333-700 exhibited superior electrocatalytic performance for the ORR and HER owing to the synergistic effect of Fe/Fe3C and Fe-N-C active sites.

A facile synthetic strategy for iron, aniline-based non-precious metal catalysts for polymer electrolyte membrane fuel cells.

The development of a low cost and highly active alternative to the commercial Pt/C catalysts used in the oxygen reduction reaction (ORR) requires a facile and environmentally-friendly synthesis process to facilitate large-scale production and provide an effective replacement. Transition metals, in conjunction with nitrogen-doped carbon, are among the most promising substitute catalysts because of their high activity, inexpensive composition, and high carbon monoxide tolerance. We prepared a polyaniline-derived Fe-N-C catalyst for oxygen reduction using a facile one-pot process with no additional reagents. This process was carried out by ultrasonicating a mixture containing an iron precursor, an aniline monomer, and carbon black. The half-wave potential of the synthesized Fe-N-C catalyst for the ORR was only 10 mV less than that of a commercial Pt/C catalyst. The optimized Fe-N-C catalyst showed outstanding performance in a practical anion exchange membrane fuel cell (AEMFC), suggesting its potential as an alternative to commercial Pt/C catalysts for the ORR.

Resolution of ambiguous HLA genotyping in korean by multi-group-specific sequence-based typing.

PURPOSE: To evaluate a multi-group-specific sequence-based typing (SBT) method for resolving ambiguous results from human leukocyte antigen (HLA) genotyping. MATERIALS AND METHODS: A total of 50 samples that showed ambiguous genotypes for at least two HLA loci from HLA-A, -B, -C and -DRB1 by the conventional SBT assay were evaluated using a new SBT test, the AVITA plus assay. The most likely HLA genotypes for the respective samples considering allele frequencies in Korean were concordant between the AVITA and conventional SBT assays. RESULTS: An average of 3.3 loci among the HLA-A, -B, -C and -DRB1 loci per sample gave results with two or more possible allele combinations with the conventional SBT, and 48 (96.0%) out of 50 showed reduced numbers of possible genotypes for at least one HLA locus with the AVITA. A total of 41, 43, 42, and 38 cases among the 50 samples showed ambiguous results for HLA-A, -B, -C, and -DRB1 typing by the conventional SBT, respectively. The average numbers of possible allele combinations for the respective four HLA loci were 8.2, 6.7, 5.9, and 3.2, and they were reduced to 1.5, 2.2, 4.4, and 1.8, respectively, by the AVITA. Ambiguity was resolved by the AVITA in 33 (80.5%), 31 (72.1%), 17 (40.5%) and 28 (73.7%) samples among the ambiguous cases from the conventional SBT for HLA-A, -B, -C, and -DRB1 typing, respectively. CONCLUSION: The multi-group-specific SBT method considerably reduced the number of ambiguous results, and thus may be useful for accurate HLA typing in clinical laboratories.