Tailored Electronic Structure of Ir in High Entropy Alloy for Highly Active and Durable Bifunctional Electrocatalyst for Water Splitting under an Acidic Environment.

Proton-exchange-membrane water electrolysis (PEMWE) requires an efficient and durable bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, Ir-based electrocatalyst is designed using the high entropy alloy (HEA) platform of ZnNiCoIrX with two elements (X: Fe and Mn). A facile dealloying in the vacuum system enables the construction of a nanoporous structure with high crystallinity using Zn as a sacrificial element. Especially, Mn incorporation into HEAs tailors the electronic structure of the Ir site, resulting in the d-band center being far away from the Fermi level. Downshifting of the d-band center weakens the adsorption energy with reaction intermediates, which is beneficial for catalytic reactions. Despite low Ir content, ZnNiCoIrMn delivers only 50 mV overpotential for HER at -50 mA cm-2 and 237 mV overpotential for the OER at 10 mA cm-2 . Furthermore, ZnNiCoIrMn shows almost constant voltage for the HER and OER for 100 h and a high stability number of 3.4 × 105 nhydrogen nIr -1 and 2.4 × 105 noxygen nIr -1 , demonstrating the exceptional durability of the HEA platform. The compositional engineering of ZnNiCoIrMn limits the diffusion of elements by high entropy effects and simultaneously tailors the electronic structure of active Ir sites, resulting in the modified cohesive and adsorption energies, all of which can suppress the dissolution of elements.

Copper Nitride Nanowires Printed Li with Stable Cycling for Li Metal Batteries in Carbonate Electrolytes.

The practical implementation of the lithium metal anode is hindered by obstacles such as Li dendrite growth, large volume changes, and poor lifespan. Here, copper nitride nanowires (Cu3 N NWs) printed Li by a facile and low-cost roll-press method is reported, to operate in carbonate electrolytes for high-voltage cathode materials. Through one-step roll pressing, Cu3 N NWs can be conformally printed onto the Li metal surface, and form a Li3 N@Cu NWs layer on the Li metal. The Li3 N@Cu NWs layer can assist homogeneous Li-ion flux with the 3D channel structure, as well as the high Li-ion conductivity of the Li3 N. With those beneficial effects, the Li3 N@Cu NWs layer can guide Li to deposit into a dense and planar structure without Li-dendrite growth. Li metal with Li3 N@Cu NWs protection layer exhibits outstanding cycling performances even at a high current density of 5.0 mA cm-2 with low overpotentials in Li symmetric cells. Furthermore, the stable cyclability and improved rate capability can be realized in a full cell using LiCoO2 over 300 cycles. When decoupling the irreversible reactions of the cathode using Li4 Ti5 O12 , stable cycling performance over 1000 cycles can be achieved at a practical current density of ≈2 mA cm-2 .

Unusual Na+ Ion Intercalation/Deintercalation in Metal-Rich Cu1.8S for Na-Ion Batteries.

A key issue with Na-ion batteries is the development of active materials with stable electrochemical reversibility through the understanding of their sodium storage mechanisms. We report a sodium storage mechanism and properties of a new anode material, digenite Cu1.8S, based on its crystallographic study. It is revealed that copper sulfides (Cu xS) can have metal-rich formulas ( x ≥ 1.6), due to the unique oxidation state of +1 found in group 11 elements. These phases enable the unit cell to consist of all strong Cu-S bonds and no direct S-S bonds, which are vulnerable to external stress/strain that could result in bond cleavage as well as decomposition. Because of its structural rigidness, the Cu1.8S shows an intercalation/deintercalation reaction mechanism even in a low potential window of 0.1-2.2 V versus Na/Na+ without irreversible phase transformation, which most of the metal sulfides experience through a conversion reaction mechanism. It uptakes, on average, 1.4 Na+ ions per unit cell (∼250 mAh g-1) and exhibits ∼100% retention over 1000 cycles at 2C in a tuned voltage range of 0.5-2.2 V through an overall solid solution reaction with negligible phase separation.

Synthesis of transition metal sulfide and reduced graphene oxide hybrids as efficient electrocatalysts for oxygen evolution reactions.

The development of electrochemical devices for renewable energy depends to a large extent on fundamental improvements in catalysts for oxygen evolution reactions (OERs). OER activity of transition metal sulfides (TMSs) can be improved by compositing with highly conductive supports possessing a high surface-to-volume ratio, such as reduced graphene oxide (rGO). Herein we report on the relationship between synthetic conditions and the OER catalytic properties of TMSs and rGO (TMS-rGO) hybrids. Starting materials, reaction temperature and reaction time were controlled to synergistically boost the OER catalytic activity of TMS-rGO hybrids. Our results showed that (i) compared with sulfides, hydroxides are favourable as starting materials to produce the desired TMS-rGO hybrid nanostructure and (ii) high reaction temperatures and longer reaction times can increase physico-chemical interaction between TMSs and rGO supports, resulting in highly efficient OER catalytic activity.

Microstructural control of new intercalation layered titanoniobates with large and reversible d-spacing for easy Na+ ion uptake.

Key issues for Na-ion batteries are the development of promising electrode materials with favorable sites for Na+ ion intercalation/deintercalation and an understanding of the reaction mechanisms due to its high activation energy and poor electrochemical reversibility. We first report a layered H0.43Ti0.93Nb1.07O5 as a new anode material. This anode material is engineered to have dominant (200) and (020) planes with both a sufficiently large d-spacing of ~8.3 Å and two-dimensional ionic channels for easy Na+ ion uptake, which leads to a small volume expansion of ~0.6 Å along the c direction upon Na insertion (discharging) and the lowest energy barrier of 0.19 eV in the [020] plane among titanium oxide-based materials ever reported. The material intercalates and deintercalates reversibly 1.7 Na ions (~200 mAh g-1) without a capacity fading in a potential window of 0.01 to 3.0 V versus Na/Na+. Na insertion/deinsertion takes place through a solid-solution reaction without a phase separation, which prevents coherent strain or stress in the microstructure during cycling and ensures promising sodium storage properties. These findings demonstrate a great potential of H0.43Ti0.93Nb1.07O5 as the anode, and our strategy can be applied to other layered metal oxides for promising sodium storage properties.

WO3/W:BiVO4/BiVO4 graded photoabsorber electrode for enhanced photoelectrocatalytic solar light driven water oxidation.

We demonstrate the dual advantages of graded photoabsorbers in mesoporous metal oxide-based hetero interfacial photoanodes in improving photogenerated charge carrier (e-/h+) separation for the solar light-driven water-oxidation process. The pre-deposition of sol-gel-derived, tungsten-doped bismuth vanadate (W:BiVO4) onto a primary BiVO4 water oxidation layer forms graded interfaces, which facilitate charge transfer from the primary photoabsorber to the charge transport layer, thereby superseding the thickness-controlled charge recombination at the BiVO4 water oxidation catalyst. As a result, the WO3/BiVO4 hetero photoanode containing the photoactive W:BiVO4 interfacial layer showed 130% higher photocurrent than that of the interfacial layer-free hetero photoelectrode owing to the enhanced charge separation led water oxidation process.

CALR, JAK2, and MPL mutation profiles in patients with four different subtypes of myeloproliferative neoplasms: primary myelofibrosis, essential thrombocythemia, polycythemia vera, and myeloproliferative neoplasm, unclassifiable.

OBJECTIVES: We investigated mutation profiles of CALR, JAK2, and MPL in 199 Korean patients with myeloproliferative neoplasms (MPNs). METHODS: In total, 199 patients with MPN (54 primary myelofibrosis [PMF], 79 essential thrombocythemia [ET], 58 polycythemia vera [PV], and eight MPN-unclassifiable [MPN-U]) and 4 patients with acute panmyelosis with myelofibrosis (APMF) were retrospectively subjected to Sanger sequencing for CALR, JAK2, and MPL. RESULTS: The overall frequency of CALR mutations was 12.6% (type 1 mutation, 16 patients; type 2 mutation, nine patients): most frequent in MPN-U (37.5%), followed by ET (17.7%) and PMF (14.8%). CALR mutations were not found in PV or APMF. CALR and JAK2 or MPL mutations were mutually exclusive. In PMF, the CALR mutations were associated with lower levels of leukocytes, lower bone marrow cellularity, and higher number of megakaryocytes. Patients with CALR-mutated ET more frequently progressed to the accelerated or blast phases compared with patients with JAK2 mutations. CALR mutations were frequently observed in the JAK2-negative MPNs, most frequently in MPN-U. CONCLUSIONS: The prognostic significance of CALR mutations likely differs among the MPN subtypes.

Asymmetric aneuploidy in mesenchymal stromal cells detected by in situ karyotyping and fluorescence in situ hybridization: suggestions for reference values for stem cells.

Cytogenetic testing is important to ensure patient safety before therapeutic application of mesenchymal stromal cells (MSCs). However, the standardized methods and criteria for the screening of chromosomal abnormalities of MSCs have not yet been determined. We investigated the frequency of cytogenetic aberrations in MSCs using G-banding and fluorescence in situ hybridization (FISH) and suggest reference values for aneuploidy in MSCs. Cytogenetic analysis was performed on 103 consecutive cultures from 68 MSCs (25 adipose-origin, 20 bone marrow-origin, 18 cord blood-origin, and 5 neural stem cells; 8 from adipose tissue of patients with breast cancer and 60 from healthy donors). We compared the MSC aneuploidy patterns with those of hematological malignancies and benign hematological diseases. Interphase FISH showed variable aneuploid clone proportions (1%-20%) in 68 MSCs. The aneuploidy patterns were asymmetric, and aneuploidy of chromosomes 16, 17, 18, and X occurred most frequently. Clones with polysomy were significantly more abundant than those with monosomy. The cutoff value of maximum polysomy rates (upper 95th percentile value) was 13.0%. By G-banding, 5 of the 61 MSCs presented clonal chromosomal aberrations. Aneuploidy was asymmetric in the malignant hematological diseases, while it was symmetric in the benign hematological diseases. We suggest an aneuploidy cutoff value of 13%, and FISH for aneuploidy of chromosomes 16, 17, 18, and X would be informative to evaluate the genetic stability of MSCs. Although it is unclear whether the aneuploid clones might represent the senescent cell population or transformed cells, more attention should be focused on the safety of MSCs, and G-banding combined with FISH should be performed.

MYD88 L265P mutations are correlated with 6q deletion in Korean patients with Waldenström macroglobulinemia.

Waldenström macroglobulinemia (WM) is a malignant lymphoplasma-proliferative disorder with IgM monoclonal gammopathy. A recent whole-genome study identified MYD88 L265P as the key mutation in WM. We investigated MYD88 mutations in conjunction with cytogenetic study in 22 consecutive Korean WM patients. Conventional G-banding and interphase fluorescence in situ hybridization (FISH) were performed at regions including 6q21 using bone marrow (BM) aspirates. Sixteen patients were subjected to Sanger sequencing-based MYD88 mutation study. Five patients (28%) showed cytogenetic aberrations in G-banding. The incidence of 6q21 deletion was 17% by conventional G-banding and 37% by FISH. Ten patients (45%) showed cytogenetic aberrations using FISH: 6q deletion in eight (37%) and IGH rearrangement in four (18%). Two patients had both the 6q deletion and IGH rearrangement, and two had only the IGH rearrangement. Eleven patients (69%) presented with the MYD88 L265P mutation. MYD88 mutations were significantly associated with the presence of 6q deletions (P = 0.037). Six patients with the 6q deletion for whom sequencing was possible were found to harbor MYD88 mutations. The MYD88 L265P mutation was also associated with increased lymphocyte burden in BM biopsy. This is the first report of high frequency MYD88 L265P mutations in Korean WM patients.

Fluorescence in situ hybridization panel for monitoring of minimal residual disease in patients with double minute chromosomes.

A double minute chromosome (dmin) is a small fragment of extrachromosomal DNA bearing amplified genes observed in malignancies. We investigated the incidence and characteristics of dmins in hematologic malignancies, and the quantitative changes during the treatment follow-up. Once a dmin was observed in conventional G-banding, it was characterized using fluorescence in situ hybridization (FISH) with the panel of MYC, NMYC, and MLL probes. Quantitative changes of malignant cells were measured using G-banding and FISH during the follow up. Dmins were observed in 1.23% of patients (6/489) at the initial diagnosis including 4 with MYC amplification, 1 with MLL and 1 with NMYC. All 6 had complex karyotypes and showed short overall survival (7.7 months). In follow-up specimens, FISH detected dmins in 11 cases out of which G-banding detected dmins in 9 cases. The number of dmins detected by FISH and G-banding did not correlate well. Amplification of NMYC in dmins is reported for the first time. A FISH panel composed of frequently amplified oncogenes (MYC, NMYC, and MLL) in dmins is useful for characterization of dmins. FISH is a sensitive method in detecting dmins and will be useful in monitoring of the minimal residual disease.

The application of an in situ karyotyping technique for mesenchymal stromal cells: a validation and comparison study with classical G-banding.

The cytogenetic analysis of mesenchymal stromal cells (MSCs) is essential for verifying the safety and stability of MSCs. An in situ technique, which uses cells grown on coverslips for karyotyping and minimizes cell manipulation, is the standard protocol for the chromosome analysis of amniotic fluids. Therefore, we applied the in situ karyotyping technique in MSCs and compared the quality of metaphases and karyotyping results with classical G-banding and chromosomal abnormalities with fluorescence in situ hybridization (FISH). Human adipose- and umbilical cord-derived MSC cell lines (American Type Culture Collection PCS-500-011, PCS-500-010) were used for evaluation. The quality of metaphases was assessed by analyzing the chromosome numbers in each metaphase, the overlaps of chromosomes and the mean length of chromosome 1. FISH was performed in the interphase nuclei of MSCs for 6q, 7q and 17q abnormalities and for the enumeration of chromosomes via oligo-FISH in adipose-derived MSCs. The number of chromosomes in each metaphase was more variable in classical G-banding. The overlap of chromosomes and the mean length of chromosome 1 as observed via in situ karyotyping were comparable to those of classical G-banding (P=0.218 and 0.674, respectively). Classical G-banding and in situ karyotyping by two personnel showed normal karyotypes for both cell lines in five passages. No numerical or structural chromosomal abnormalities were found by the interphase-FISH. In situ karyotyping showed equivalent karyotype results, and the quality of the metaphases was not inferior to classical G-banding. Thus, in situ karyotyping with minimized cell manipulation and the use of less cells would be useful for karyotyping MSCs.

Effects of granulocyte-colony stimulating factor and the expression of its receptor on various malignant cells.

BACKGROUND: Granulocyte-colony stimulating factor (G-CSF) is extensively used to improve neutrophil count during anti-cancer chemotherapy. We investigated the effects of G-CSF on several leukemic cell lines and screened for the expression of the G-CSF receptor (G-CSFR) in various malignant cells. METHODS: We examined the effects of the most commonly used commercial forms of G-CSF (glycosylated lenograstim and nonglycosylated filgrastim) on various leukemic cell lines by flow cytometry. Moreover, we screened for the expression of G-CSFR mRNA in 38 solid tumor cell lines by using real-time PCR. RESULTS: G-CSF stimulated proliferation (40-80% increase in proliferation in treated cells as compared to that in control cells) in 3 leukemic cell lines and induced differentiation of AML1/ETO+ leukemic cells. Among the 38 solid tumor cell lines, 5 cell lines (hepatoblastoma, 2 breast carcinoma, squamous cell carcinoma of the larynx, and melanoma cell lines) showed G-CSFR mRNA expression. CONCLUSION: The results of the present study show that therapeutic G-CSF might stimulate the proliferation and differentiation of malignant cells with G-CSFR expression, suggesting that prescreening for G-CSFR expression in primary tumor cells may be necessary before using G-CSF for treatment.