Tuning Carbon Defect in Copper Single-Atom Catalysts for Efficient Oxygen Reduction.

Defect chemistry in carbon matrix shows great potential for promoting the oxygen reduction reaction (ORR) of metal single-atom catalysts. Herein, a modified pyrolysis strategy is proposed to tune carbon defects in copper single-atom catalysts (Cu-SACs) to fully understand their positive effect on the ORR activity. The optimized Cu-SACs with controllable carbon defect degree and enhanced active specific surface area can exhibit improved ORR activity with a half-wave potential of 0.897 VRHE , ultrahigh limiting current density of 6.5 mA cm-2 , and superior turnover frequency of 2.23 e site-1 s-1 . The assembled Zn-air batteries based on Cu-SACs can also show well-retained reversibility and voltage platform over 1100 h charge/discharge period. Density functional theory calculations reveal that suitable carbon defects can redistribute charge density of Cu-N4 active sites to weaken the O-O bond in adsorbed OOH* intermediate and thus reduce its dissociation energy. This discovery offers a universal strategy for fabricating superior single-atom catalysts with high-efficiency active sites toward energy-directed applications.

ZIF-8/ZIF-67-Derived Co-Nx -Embedded 1D Porous Carbon Nanofibers with Graphitic Carbon-Encased Co Nanoparticles as an Efficient Bifunctional Electrocatalyst.

Herein, an approach is reported for fabrication of Co-Nx -embedded 1D porous carbon nanofibers (CNFs) with graphitic carbon-encased Co nanoparticles originated from metal-organic frameworks (MOFs), which is further explored as a bifunctional electrocatalyst for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Electrochemical results reveal that the electrocatalyst prepared by pyrolysis at 1000 °C (CoNC-CNF-1000) exhibits excellent catalytic activity toward ORR that favors the four-electron ORR process and outstanding long-term stability with 86% current retention after 40 000 s. Meanwhile, it also shows superior electrocatalytic activity toward OER, reaching a lower potential of 1.68 V at 10 mA cm-2 and a potential gap of 0.88 V between the OER potential (at 10 mA cm-2 ) and the ORR half-wave potential. The ORR and OER performance of CoNC-CNF-1000 have outperformed commercial Pt/C and most nonprecious-metal catalysts reported to date. The remarkable ORR and OER catalytic performance can be mainly attributable to the unique 1D structure, such as higher graphitization degree beneficial for electronic mobility, hierarchical porosity facilitating the mass transport, and highly dispersed CoNx C active sites functionalized carbon framework. This strategy will shed light on the development of other MOF-based carbon nanofibers for energy storage and electrochemical devices.

A case of KAT6A syndrome with a newly discovered mutation in the KAT6A gene, mainly manifested as bone marrow failure syndrome.

Objective: The clinical and genetic characteristics of a child with inherited bone marrow failure syndrome as prominent clinical manifestations and special facial features were analyzed, and the etiology and mechanism were explored in, combination with clinical practice. Methods: Blood samples and clinical information were collected separately from the proband and their biological parents. The pathogenic variant was verified using next-generation sequencing technology screening, and the candidate variable sites were confirmed by using Sanger sequencing among all members of the family. Results: A heterozygous nonsense mutation in exon 17 of KAT6A (NM_006766), c.4177G > T (p.E1393*) predicted to cause truncation within the acidic domain of the protein was identified. Pedigree analysis did not reveal any variation in this locus between the proband's father and mother. No report of this pathogenic variant was found in a literature search of domestic and foreign databases, indicating that it is a newly discovered mutation. According to the guidelines of the American College of Medical Genetics, the variation was preliminarily determined to be a pathogenic. The newly discovered heterozygous mutation in KAT6A may be the cause of the disease in this child. Additionally, inherited bone marrow failure syndrome is a prominent manifestation. Conclusion: This study not only provides us with an in-depth understanding of this rare syndrome but also deepens our understanding of the function of KAT6A.

General metal-organic framework-derived strategy to synthesize yolk-shell carbon-encapsulated nickelic spheres for sodium-ion batteries.

Transition-metal compounds have attracted enormous attention as potential energy storage materials for their high theoretical capacity and energy density. However, the most present transition-metal compounds still suffer from severe capacity decay and limited rate capability due to the lack of robust architectures. Herein, a general metal-organic framework-derived route is reported to fabricate hierarchical carbon-encapsulated yolk-shell nickelic spheres as anode materials for sodium-ion batteries. The nickelic metal-organic framework (Ni-MOF) precursors can be in situ converted into hierarchical carbon-encapsulated Ni2P (Ni2P/C), NiS2 (NiS2/C) and NiSe2 (NiSe2/C) by phosphorization, sulfuration, and selenation reaction, respectively, and maintain their yolk-shell sphere-like morphology. The as-synthesized Ni2P/C sample can deliver much lower polarization and discharge platform, smaller voltage gap, and faster kinetics in comparison with that of the other two counterparts, and thus achieve higher initial specific capacity (3222.1/1979.3 mAh g-1) and reversible capacity of 765.4 mAh g-1 after 110 cycles. This work should provide new insights into the phase and structure engineering of carbon-encapsulated transition-metal compound electrodes via MOFs template for advanced battery systems.

[Prevalence and molecular analysis of α-thalassemia in preschool children in Chongqing city].

OBJECTIVE: To investigate the incidence and the gene mutation frequencies and patterns of α-thalassemia in preschool children in Chongqing city. METHODS: Cluster random sampling was used. A total of 1057 preschool children in three areas of Chongqing were screened by using routine blood test and hemoglobin electrophoresis analysis. Molecular analysis carried out for all the samples. RESULTS: Of the 1057 samples, 55 cases were diagnosed as being carriers of α-thalassemia, which included 80 allele genes. Therefore, the frequency of α-thalassemia carriers in Chongqing was 5.20%. Of the 55 α-thalassemia carriers, five different deletions of α-thalassemia were identified, the three most common deletion types and proportions were 54.55% for the -α(3.7) deletion, 18.18% for --(SEA) deletion, and 9.08% for the -α(4.2) deletion, respectively; eight types of nondeletion defects were determined, containing one case of Hb Quong Sze and seven novel mutations of a-globin gene. Furthermore, 24 cases of α-Triplication were detected with the α-Triplication carrier rate of 2.55%. In addition, in this study we also found two cases of abnormal hemoglobin disorders occurred on α-globin gene, Hb J-Wenchang-Wuming and Hb Arya. Hb Arya was characterized in the Chinese population for the first time confirmed by literature retrieval. CONCLUSION: In this study, we have clarified the carrier frequency and molecular spectrum of α-thalassemia in Chongqing, and we first reported the carrier incidence of α-Triplication in Chongqing. The materials obtained from this study would be of valuable reference for genetic counseling and the examination instruction of children in this area.

Prevalence and genetic analysis of α-thalassemia and ß-thalassemia in Chongqing area of China.

BACKGROUND AND AIMS: Thalassemia is one of the most common hereditary disorders. This study aimed to investigate the prevalence of thalassemia and the mutation spectrum in Chongqing, the southern area of China. METHODS: A total of 1057 children were recruited from Chongqing. Hematological parameters were examined and globin genes were genetically analyzed. RESULTS: The total frequency of thalassemia carriers was 7.76% in this group of children. Among these, α-thalassemia was 5.20%, ß-thalassemia was 1.99% and abnormal hemoglobin variant was 0.57%. Furthermore, 24 cases of α-triplication were detected, frequency of which was 2.55%. The true prevalence of silent α-thalassemia was first reported in this study. In addition, six novel mutations that give rise to α-thalassemia and two rare abnormal hemoglobin variants were first identified in Chinese population. CONCLUSIONS: Our data suggested that the population in Chongqing are at high risk of α- and ß-thalassemia. The findings will be useful for genetic counseling and the prevention of severe thalassemias in this area.

[Prevalence and molecular analysis of ß-thalassemia in children of Han ethnicity in Chongqing city].

OBJECTIVE: To investigate the incidence and the gene mutation frequencies and patterns of ß-thalassemia (ß-Thal) in ethnic Han children in Chongqing city. METHOD: A total of 1726 children were screened by using automatic hemocytic analyzer, cellulose acetate electrophoresis and fetal hemoglobin alkali denaturation test. Samples with mean corpuscular volume (MCV) < 80 fl, cell hemoglobin content (MCH) < 27 pg and hemoglobin A2 (HbA2) levels >3.3%, fetal hemoglobin (HbF) >2% for ß-Thal screening indicators. The positive samples of screening indicators were detected and identified by PCR-reverse dot blot method for 18 common ß-Thal mutations in Chinese populations, unknown mutations samples were subjected to DNA sequencing analysis of the ß-globin gene. RESULT: Twenty-five cases of ß-Thal carriers were observed from the 1726 samples, with 24 cases of ß-Thal heterozygote and one case of double heterozygote. Therefore, the ß-Thal carrier rate was 1.51%. After 1726 peripheral venous blood samples analyzed by hematological parameters, 164 positive cases of ß-Thal screening indicators were found, with the positive rate being 9.50% (164/1726). A total of 6 different gene mutations were detected, the four most common mutations were as the following: CD41-42, IVS-II-654, CD17 and beta E. These four mutations as the major types in this area accounted for 88.00% of all the mutations. In addition, one rare mutation of 5 'UTR; + (43 -40) was found, and one case of the hemoglobin variant of Hb Zurich was reported in Chinese people for the first time. CONCLUSION: Chongqing is a high risk region of the ß-Thal. Epidemiological Data from the research was useul for the genetic counseling and the prevention of ß-Thal major.