Dopant Evolution in Electrocatalysts after Hydrogen Oxidation Reaction in an Alkaline Environment.

Introduction of interstitial dopants has opened a new pathway to optimize nanoparticle catalytic activity for, e.g., hydrogen evolution/oxidation and other reactions. Here, we discuss the stability of a property-enhancing dopant, B, introduced through the controlled synthesis of an electrocatalyst Pd aerogel. We observe significant removal of B after the hydrogen oxidation reaction. Ab initio calculations show that the high stability of subsurface B in Pd is substantially reduced when H is adsorbed/absorbed on the surface, favoring its departure from the host nanostructure. The destabilization of subsurface B is more pronounced, as more H occupies surface sites and empty interstitial sites. We hence demonstrate that the H2 fuel itself favors the microstructural degradation of the electrocatalyst and an associated drop in activity.

In-depth circulating tumor DNA sequencing for prognostication and monitoring in natural killer/T-cell lymphomas.

Background: Epstein-Barr virus (EBV) quantitation and current imaging modalities are used for diagnosis and disease monitoring in Extranodal NK/T cell lymphoma (ENKTL) but have limitations. Thus, we explored the utility of circulating tumor DNA (ctDNA) as a diagnostic biomarker. Methods: Through in-depth sequencing of 118 blood samples collected longitudinally at different time points from 45 patients, we examined the mutational profile of each sample, estimated its impact on the clinical outcome, and assessed its role as a biomarker in comparison with EBV DNA quantitation. Results: The ctDNA concentration was correlated with treatment response, stage, and EBV DNA quantitation. The detection rate of ctDNA mutation was 54.5%, with BCOR (21%) being the most commonly mutated gene in newly diagnosed patients; TP53 mutation (33%) was the most prevalent in patients that experienced a relapse. Additionally, patients in complete remission exhibited a rapid clearance of ENKTL-related somatic mutations, while relapsed patients frequently presented with persisting or emerging mutations. We detected ctDNA mutations in EBV-negative patients (50%) and mutation clearance in EBV-positive patients in remission, suggesting ctDNA genotyping as an efficient complementary monitoring method for ENKTL. Additionally, mutated DDX3X (PFS HR, 8.26) in initial samples predicted poor outcome. Conclusion: Our results suggest that ctDNA analysis can be used to genotype at diagnosis and estimate the tumor burden in patients with ENKTL. Furthermore, ctDNA dynamics indicate the potential use of testing it to monitor therapeutic responses and develop new biomarkers for precision ENKTL therapy.

Gas-Permeable Iron-Doped Ceria Shell on Rh Nanoparticles with High Activity and Durability.

Strong metal-support interaction (SMSI) is a promising strategy to control the structure of the supported metal catalyst. Especially, encapsulating metal nanoparticles through SMSI can enhance resistance against sintering but typically blocks the access of reactants onto the metal surface. Here, we report gas-permeable shells formed on Rh nanoparticles with enhanced activity and durability for the surface reaction. First, Fe species were doped into ceria, enhancing the transfer of surface oxygen species. When Rh was deposited onto the Fe-doped ceria (FC) and reduced, a shell was formed on Rh nanoparticles. Diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) results show that the shell is formed upon reduction and removed upon oxidation reversibly. CO adsorption on the Rh surface through the shell was confirmed by cryo-DRIFTS. The reverse water gas shift (RWGS) reaction (CO2 + H2 → CO + H2O) occurred on the encapsulated Rh nanoparticles effectively with selective CO formation, whereas bare Rh nanoparticles deposited on ceria produced methane as well. The CO adsorption became much weaker on the encapsulated Rh nanoparticles, and H2-spillover occurred more on the FC, resulting in high activity for RWGS. The exposed Rh nanoparticles deposited on ceria presented degradation at 400 °C after 150 h of RWGS, whereas the encapsulated Rh nanoparticles showed no degradation with superior durability. Enhancing surface oxygen transfer can be an efficient way to form gas-permeable overlayers on metal nanoparticles with high activity and durability.

Electrodeposited Sn-Cu@Sn dendrites for selective electrochemical CO2 reduction to formic acid.

Large-scale CO2 electrolysis can be applied to store renewable energy in chemicals. Recent developments in gas diffusion electrodes now enable a commercially relevant current density. However, the low selectivity of the CO2 reduction reaction (CO2RR) still hinders practical applications. The selectivity of the CO2RR highly depends on the electrocatalyst. Sn catalysts are considered promising cathode materials for the production of formic acid. The selectivity of Sn catalysts can be regulated by controlling their morphology or alloying them with secondary metals. Herein, we enhanced the selectivity of CO2 reduction to formic acid by synthesizing Sn-Cu@Sn dendrites that have a core@shell architecture. The Sn-Cu@Sn dendrites were prepared by a scalable electro-deposition method. The electronic structure was modified to suppress a reaction pathway for CO production on the Sn surface. Notably, the Sn shell inhibited the cathodic corrosion of Cu during the CO2RR. On a gas diffusion electrode, the Sn-Cu@Sn dendrites exhibited 84.2% faraday efficiency to formic acid for 120 h with high stability.

Controlled Doping of Electrocatalysts through Engineering Impurities.

Fuel cells recombine water from H2 and O2 thereby can power, for example, cars or houses with no direct carbon emission. In anion-exchange membrane fuel cells (AEMFCs), to reach high power densities, operating at high pH is an alternative to using large volumes of noble metals catalysts at the cathode, where the oxygen-reduction reaction occurs. However, the sluggish kinetics of the hydrogen-oxidation reaction (HOR) hinders upscaling despite promising catalysts. Here, the authors observe an unexpected ingress of B into Pd nanocatalysts synthesized by wet-chemistry, gaining control over this B-doping, and report on its influence on the HOR activity in alkaline conditions. They rationalize their findings using ab initio calculations of both H- and OH-adsorption on B-doped Pd. Using this "impurity engineering" approach, they thus design Pt-free catalysts as required in electrochemical energy conversion devices, for example, next generations of AEMFCs, that satisfy the economic and environmental constraints, that is, reasonable operating costs and long-term stability, to enable the "hydrogen economy."

Highly Durable Heterogeneous Atomic Catalysts.

ConspectusSingle-atom catalysts (SACs), in which surface metal atoms are isolated on the surface of a support, have received a tremendous amount of attention recently because this structure would utilize precious metals fully, without occluding atoms inside nanoparticles, and enable unique surface reactions which typical nanoparticle catalysts cannot induce. Various synthesis methods and characterization techniques have been reported that yield enhanced activity and selectivity. The single-atom structures were realized on various supports such as metal oxide/carbide/nitride, porous materials derived from zeolite or metal-organic frameworks, and carbon-based materials. Additionally, when the metal atoms are isolated on other metal nanoparticles, this material is denoted as a single-atom alloy (SAA). The single-atom structure, however, cannot catalyze the surface reaction that necessitates ensemble sites, where several metal atoms are located nearby. Very recently, ensemble catalysts, in which all of the metal atoms are exposed at the surface with neighboring metal atoms, have been reported, overcoming the limitation of single-atom catalysts. We call all of these materials (SACs, SAAs, and ensemble catalyst) heterogeneous atomic catalysts, indicating that the surface metal atomic structure is intentionally controlled. To use these atomic catalysts for practical applications, high durability should be guaranteed, which has received relatively less attention.In this Account, we discuss recent examples of heterogeneous atomic catalysts with high durability. Structural stability, indicating whether the surface atomic structure is thermodynamically stable, should be carefully considered. Typically, metal atoms are immobilized on a highly defective support, stabilizing both the metal atom and the support. The surface metal atoms might become destabilized upon the adsorption of chemical intermediates. This transient behavior should be carefully monitored; density functional theory (DFT) calculations are particularly useful in estimating this stability. Aside from structural stability, the catalyst performance can be degraded significantly by poisoning with impurities. If the single-atom sites are susceptible to impurities with stronger adsorption, the surface reaction would not occur efficiently, leading to a decrease in activity without structure degradation. A long-term durability test should be performed for target reactions. Heterogeneous atomic catalysts have been used for various electrochemical, photocatalytic, and thermal reactions. Although electricity, light, and heat are just different forms of energy, the specific conditions which the catalyst should satisfy are different. Whereas precious metal atoms are mostly used as surface-active sites, the properties of the support are different depending on the type of reaction. For example, the support should have high conductivity for electrochemical reactions, it should be able to absorb light for photocatalytic reactions, and it should be durable at high temperature in the presence of steam for thermal reactions. Highly durable heterogeneous atomic catalysts are certainly possible with a great potential for practical applications. These new catalysts can accelerate the current paradigm shift toward more sustainable chemical production.

Lens-Shaped Carbon Particles with Perpendicularly-Oriented Channels for High-Performance Proton Exchange Membrane Fuel Cells.

Two-dimensional sheet-like mesoporous carbon particles are promising for maximizing the number of active sites and the mass transport efficiency of proton exchange membrane fuel cells (PEMFCs). Herein, we develop a series of lens-shaped mesoporous carbon (LMC) particles with perpendicularly oriented channels (diameter = 60 nm) and aspect ratios (ARs) varying from 2.1 to 6.2 and apply them for the fabrication of highly efficient PEMFCs. The membrane emulsification affords uniform-sized, lens-shaped block copolymer particles, which are successfully converted into the LMC particles with well-ordered vertical channels through hyper-cross-linking and carbonization steps. Then, an ultralow amount (1 wt %) of platinum (Pt) is loaded into the particles. The LMC particles with higher ARs are packed with a higher density in the cathode and are better aligned on the cathode surface compared to the LMC particles with lower ARs. Thus, the well-ordered channels in the particles facilitate the mass transport of the reactants and products, significantly increasing the PEMFC performance. For example, the LMC particles with the AR of 6.2 show the highest initial single cell performance of 1135 mW cm-2, and the cell exhibits high durability with 1039 mW cm-2 even after 30 000 cycles. This cell performance surpasses that of commercial Pt/C catalysts, even at 1/20 of the Pt loading.

Quasi-graphitic carbon shell-induced Cu confinement promotes electrocatalytic CO2 reduction toward C2+ products.

For steady electroconversion to value-added chemical products with high efficiency, electrocatalyst reconstruction during electrochemical reactions is a critical issue in catalyst design strategies. Here, we report a reconstruction-immunized catalyst system in which Cu nanoparticles are protected by a quasi-graphitic C shell. This C shell epitaxially grew on Cu with quasi-graphitic bonding via a gas-solid reaction governed by the CO (g) - CO2 (g) - C (s) equilibrium. The quasi-graphitic C shell-coated Cu was stable during the CO2 reduction reaction and provided a platform for rational material design. C2+ product selectivity could be additionally improved by doping p-block elements. These elements modulated the electronic structure of the Cu surface and its binding properties, which can affect the intermediate binding and CO dimerization barrier. B-modified Cu attained a 68.1% Faradaic efficiency for C2H4 at -0.55 V (vs RHE) and a C2H4 cathodic power conversion efficiency of 44.0%. In the case of N-modified Cu, an improved C2+ selectivity of 82.3% at a partial current density of 329.2 mA/cm2 was acquired. Quasi-graphitic C shells, which enable surface stabilization and inner element doping, can realize stable CO2-to-C2H4 conversion over 180 h and allow practical application of electrocatalysts for renewable energy conversion.

Recurrent somatic mutations and low germline predisposition mutations in Korean ALL patients.

In addition to somatic mutations, germline genetic predisposition to hematologic malignancies is currently emerging as an area attracting high research interest. In this study, we investigated genetic alterations in Korean acute lymphoblastic leukemia/lymphoma (ALL) patients using targeted gene panel sequencing. To this end, a gene panel consisting of 81 genes that are known to be associated with 23 predisposition syndromes was investigated. In addition to sequence variants, gene-level copy number variations (CNVs) were investigated as well. We identified 197 somatic sequence variants and 223 somatic CNVs. The IKZF1 alteration was found to have an adverse effect on overall survival (OS) and relapse-free survival (RFS) in childhood ALL. We found recurrent somatic alterations in Korean ALL patients similar to previous studies on both prevalence and prognostic impact. Six patients were found to be carriers of variants in six genes associated with primary immunodeficiency disorder (PID). Of the 81 genes associated with 23 predisposition syndromes, this study found only one predisposition germline mutation (TP53) (1.1%). Altogether, our study demonstrated a low probability of germline mutation predisposition to ALL in Korean ALL patients.

Heterogeneous Atomic Catalysts Overcoming the Limitations of Single-Atom Catalysts.

Recent advances in heterogeneous single-atom catalysts (SACs), which have isolated metal atoms dispersed on a support, have enabled a more precise control of their surface metal atomic structure. SACs could reduce the amount of metals used for the surface reaction and have often shown distinct selectivity, which the corresponding nanoparticles would not have. However, SACs typically have the limitations of low-metal content, poor stability, oxidic electronic states, and an absence of ensemble sites. In this review, various efforts to overcome these limitations have been discussed: The metal content in the SACs could increase up to over 10 wt %; highly durable SACs could be prepared by anchoring the metal atoms strongly on the defective support; metallic SACs are reported; and the ensemble catalysts, in which all the metal atoms are exposed at the surface like the SACs but the surface metal atoms are located nearby, are also reported. Metal atomic multimers with distinct catalytic properties have been also reported. Surface metal single-atoms could be decorated with organic ligands with interesting catalytic behavior. Heterogeneous atomic catalysts, whose structure is elaborately controlled and the surface reaction is better understood, can be a paradigm with higher catalytic activity, selectivity, and durability and used in industrial applications.

Controlling the Oxidation State of Pt Single Atoms for Maximizing Catalytic Activity.

Single-atom catalysts (SACs) have emerged as promising materials in heterogeneous catalysis. Previous studies reported controversial results about the relative level in activity for SACs and nanoparticles (NPs). These works have focused on the effect of metal atom arrangement, without considering the oxidation state of the SACs. Here, we immobilized Pt single atoms on defective ceria and controlled the oxidation state of Pt SACs, from highly oxidized (Pt0 : 16.6 at %) to highly metallic states (Pt0 : 83.8 at %). The Pt SACs with controlled oxidation states were then employed for oxidation of CO, CH4 , or NO, and their activities compared with those of Pt NPs. The highly oxidized Pt SACs presented poorer activities than Pt NPs, whereas metallic Pt SACs showed higher activities. The Pt SAC reduced at 300 °C showed the highest activity for all the oxidations. The Pt SACs with controlled oxidation states revealed a crucial missing link between activity and SACs.

Changes in the oxidation state of Pt single-atom catalysts upon removal of chloride ligands and their effect for electrochemical reactions.

Single atomic Pt supported on TiC was prepared from chloride Pt precursors, then the chloride ligands were intentionally removed by increasing the reduction temperature. The 0.2 wt% Pt/TiC catalyst reduced at 300 °C had more reduced Pt single-atoms with fewer chloride ligands and exhibited the highest currents for H2O2 formation in the electrochemical oxygen reduction reaction. Controlling the oxidation state of the single-atoms is very important to maximize the activity of the single-atom catalysts.

Comprehensive Laboratory Analysis of Korean Acute Alcoholic Intoxication Patients Reveals the Need for a National Hepatitis B Virus Vaccination Program in Korea.

BACKGROUND: Acute alcoholic intoxication patients (AAIP) are a common public health problem. The aim of this study was to perform a comprehensive laboratory analysis for these patients to investigate the co-morbid medical problem. METHODS: We retrospectively reviewed laboratory findings of AAIP who were transferred to the emergency department (ED) from January 2017 to June 2017. RESULTS: A total of 160 male patients were enrolled. Sixteen patients (16/160, 10.0%) and three patients (3/160, 1.9%) had macrocytic anemia and microcytic anemia, respectively. A total of 33 patients (33/160, 20.6%) showed thrombocytopenia (<150×109 /L). Twelve patients (12/159, 7.5%) showed low serum albumin level (<3.5 g/dL). Three patients (3/160, 1.9%) had chronic kidney disease stages 3-4 based on estimated glomerular filtration rate. Six patients (6/27, 22.2%) had high hemoglobin A1c (HbA1c) level (>7.0%). Positive rates of hepatitis B surface antigen and antiHBs antibody (anti-HBs Ab) were 3.5% (5/141) and 49.0% (68/141), respectively. CONCLUSION: Patients with AAIP who were transferred to ED had various laboratory abnormalities (anemia, thrombocytopenia, high HbA1c). They had low positive rate of anti-HBs Ab. This might be a public health problem, suggesting the need of hepatitis B virus vaccination program for AAIP. Our data suggest the need of further nationwide studies.

Prognostic Implications of Monosomies in Patients With Multiple Myeloma.

BACKGROUND: Cytogenetic analysis aides in risk stratification for patients with multiple myeloma (MM). Although several cytogenetic aberrations have been reported to be prognostic, less is known about the association between the presence of monosomies and prognosis. The present study evaluated the prevalence and prognostic implications of monosomies in patients with MM. MATERIALS AND METHODS: Karyotypes were determined using conventional cytogenetics and fluorescence in situ hybridization (FISH). The prognostic effect of monosomies was evaluated by comparison with the clinical factors in MM patients with normal karyotypes. RESULTS: Karyotypes were successfully determined in 167 of the 170 patients with MM. Of these 167 patients, 52 (31.1%) had abnormal karyotypes. Univariable analyses showed that a normal karyotype, hypodiploidy, monosomies of chromosomes 13 and 16, deletion or monosomy of 13q14, and loss of X detected by metaphase analysis were each associated with reduced progression-free survival (P < .05 for each). Univariable analyses showed that a normal karyotype, hypodiploidy, monosomies of chromosomes 13 and 16, deletion or monosomy of 13q14 detected by metaphase analysis and FISH-determined RB1 (13q)/TP53 (17p) deletion were each associated with reduced overall survival (P < .05 for each). Multivariable analysis showed that hypodiploidy detected by metaphase analysis was independently prognostic of shorter progression-free survival (P < .05 for each) and that hypodiploidy, monosomy 16, and loss of Y chromosome and FISH-determined TP53 (17p) deletion were associated with reduced overall survival (P < .05 for each). CONCLUSION: In addition to known cytogenetic abnormalities, such as monosomy 13, hypodiploidy, and TP53 (17p) deletion, monosomy 16 and loss of the Y chromosome have adverse prognostic implications in patients with MM.

Detection of MYD88 L265P in patients with lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia and other B-cell non-Hodgkin lymphomas.

BACKGROUND: Recent studies have identified a high prevalence of the MYD88 L265P mutation in lymphoplasmacytic lymphoma (LPL)/Waldenstrom macroglobulinemia (WM) cases, whereas low frequencies have been observed in other B cell non-Hodgkin lymphomas (NHLs). METHODS: We evaluated the sensitivity of the mutant enrichment 3'-modified oligonucleotide (MEMO)-PCR technique, a new detection method. We examined the MYD88 L265P mutation in a series of Korean patients with LPL/WM and other B cell NHLs in bone marrow aspirates, using the MEMO-PCR technique. RESULTS: The sensitivity of MEMO-PCR was estimated to be approximately 10-16.7%. MYD88 L265P was detected in 21 of 28 LPL cases (75%) and only three of 69 B cell NHL cases (4.3%). CONCLUSION: Although MEMO-PCR had relatively low sensitivity, we confirmed the high prevalence of the MYD88 L265P mutation in Korean LPL patients. Our study suggests the diagnostic value of MYD88 L265P for differentiating B-cell NHLs.

Mutation profiling of 19 candidate genes in acute myeloid leukemia suggests significance of DNMT3A mutations.

We selected 19 significantly-mutated genes in AMLs, including FLT3, DNMT3A, NPM1, TET2, RUNX1, CEBPA, WT1, IDH1, IDH2, NRAS, ASXL1, SETD2, PTPN11, TP53, KIT, JAK2, KRAS, BRAF and CBL, and performed massively parallel sequencing for 114 patients with acute myeloid leukemias, mainly including those with normal karyotypes (CN-AML). More than 80% of patients had at least one mutation in the genes tested. DNMT3A mutation was significantly associated with adverse outcome in addition to conventional risk stratification such as the European LeukemiaNet (ELN) classification. We observed clinical usefulness of mutation testing on multiple target genes and the association with disease subgroups, clinical features and prognosis in AMLs.

A Novel Hemoglobin Variant Associated with Congenital Erythrocytosis: Hb Seoul [ß86(F2)Ala→Thr] (HBB:c.259G>A).

We report the identification of a novel hemoglobin (Hb) variant [ß86(F2)Ala→Thr; HBB: c.259G>A], Hb Seoul, causing congenital erythrocytosis due to high oxygen affinity. The patient was a 33-year-old Korean man with isolated erythrocytosis. JAK2 somatic mutations were negative. Direct sequencing analyses revealed that the patient was heterozygous for c.259G>A, while other known causative genes (BPGM, EGLN1, EPAS, EPOR and VHL) had no mutation. ß86(F2) is a critical residue that affects the oxygen affinity. The novel variant in our patient, Hb Seoul, adds to the previously reported 4 other Hb variants from ß86(F2) substitutions that cause congenital erythrocytosis.