Pathway from N‐Alkylglycine to Alkylisonitrile Catalyzed by Iron(II) and 2‐Oxoglutarate‐Dependent Oxygenases

N‐alkylisonitrile, a precursor to isonitrile‐containing lipopeptides, is biosynthesized by decarboxylation‐assisted ‐N≡C group (isonitrile) formation by using N‐alkylglycine as the substrate. This reaction is catalyzed by iron(II) and 2‐oxoglutarate (Fe/2OG) dependent enzymes. Distinct from typical oxygenation or halogenation reactions catalyzed by this class of enzymes, installation of the isonitrile group represents a novel reaction type for Fe/2OG enzymes that involves a four‐electron oxidative process. Reported here is a plausible mechanism of three Fe/2OG enzymes, Sav607, ScoE and SfaA, which catalyze isonitrile formation. The X‐ray structures of iron‐loaded ScoE in complex with its substrate and the intermediate, along with biochemical and biophysical data reveal that ‐N≡C bond formation involves two cycles of Fe/2OG enzyme catalysis. The reaction starts with an Fe^IV‐oxo‐catalyzed hydroxylation. It is likely followed by decarboxylation‐assisted desaturation to complete isonitrile installation.     

Why Boron Nitride is such a Selective Catalyst for the Oxidative Dehydrogenation of Propane

Boron‐containing materials, and in particular boron nitride, have recently been identified as highly selective catalysts for the oxidative dehydrogenation of alkanes such as propane. To date, no mechanism exists that can explain both the unprecedented selectivity, the observed surface oxyfunctionalization, and the peculiar kinetic features of this reaction. We combine catalytic activity measurements with quantum chemical calculations to put forward a bold new hypothesis. We argue that the remarkable product distribution can be rationalized by a combination of surface‐mediated formation of radicals over metastable sites, and their sequential propagation in the gas phase. Based on known radical propagation steps, we quantitatively describe the oxygen pressure‐dependent relative formation of the main product propylene and by‐product ethylene. Free radical intermediates most likely differentiate this catalytic system from less selective vanadium‐based catalysts.     

Enzyme-free and DNA-based universal platform for the construction of various logic devices based on graphene oxide and G-quadruplex

In the fields of biocomputing and biomolecular, DNA molecules are applicable to be regarded as data of logical computing platform that uses elaborate logic gates to perform a variety of tasks. Graphene oxide (GO) is a type of novel nanomaterial, which brings new research focus to materials science and biosensors due to its special selectivity and excellent quenching ability. G-quadruplex as a unique DNA structure stimulates the intelligent application of DNA assembly on the strength of its exceptional binding activity. In this paper, we report a universal logic device assisted with GO and G-quadruplex under an enzyme-free condition. Integrated with the quenching ability of GO to the TAMRA (fluorophore, Carboxytetramethylrhodamine) and the enhancement of fluorescence intensity produced by the peculiar binding of G-quadruplex to the NMM (N-methylmesoporphyrin IX), a series of basic binary logic gates (AND. OR. INHIBIT. XOR) have been designed and verified through biological experiments. Given the modularity and programmability of this strategy, two advanced logic gates (half adder and half subtractor) were realized on the basis of the same work platform. The fluorescence signals generated from different input combinations possessed satisfactory results, which provided proof of feasibility. We believe that the proposed universal logical platform that operates at the nanoscale is expected to be utilized for future applications in molecular computing as well as disease diagnosis.     

Defluoridation in aqueous solution by a composite of reduced graphene oxide decorated with cuprous oxide via sonochemical

The World Health Organization (WHO) has recommended the fluoride level in drinking water (1.5 mg/L) and defluoridation of water is an essential to remove of fluoride from contaminated water. Hence, the effective and rapid adsorbent Cuprous oxide-reduced graphene oxide (Cu₂O-RGO) composite was developed to overwhelm this concern. Sonochemical approach was adopted for the synthesis of desirable composite which was further characterized by XRD, FTIR, SEM, and EDS. The optimized composite (30 mg) shown the significant adsorption capacity of 34 mg/g of F⁻ solution (pH = 9), 70% removal of F⁻ solution from real experiment and Freundlich model was fitted than Langmuir and Temkin isotherms. The experimental results corroborate that adsorbent is the most effective for removal of fluoride from its polluted water.     

控制结晶-微波碳热还原法制备高密度LiFePO4/C

应用控制结晶法从溶液相制备球形FePO4.xH2O,再高温烧结得到FePO4前驱体,最后用微波碳热还原法合成高密度L iFePO4/C.由XRD和SEM表征该材料的结构、形貌,并测试其电化学性能.     

Arsenic biomethylation by the microorganism apiotrichum humicola in the presence of l-methionine-methyl-d3

The microorganism Apiotrichum humicola (previously known as Candida humicola) grown in the presence of either arsenate, arsenite, methylarsonic acid or dimethylarsinic acid, produces arsenic-containing metabolites in the growth medium. When L-methionine-methyl-d₃ is added to the cultures, the CD₃ label is incorporated intact into the metabolites to a considerable extent to form deuterated dimethylarsenic and trimethyl-arsenic species, indicating that S-adenosylmethionine, or some related sulphonium compound, is involved in the biological methylation. Conclusive evidence of CD₃ incorporation in the arsenicals found in the growth medium was provided by using a specially developed hydride generation-gas chromatography-mass spectrometry system (HG–GC–MS).     

RIG型磁光薄膜的研究进展及应用

随着光通信技术与光子集成电路的发展,非互易性器件作为光通信系统中重要的组成部分得到了越来越广泛的研究与应用。基于磁光效应制成的磁光隔离器和环行器是目前应用最为广泛的非互易性器件,为了将非互易性器件整块集成在硅片上,需制备性能与块状磁光材料相当的磁光薄膜。在近红外通信波段(1 550 nm),以钇铁石榴石(Y₃Fe₅O₁₂,YIG)为代表的稀土铁石榴石(RIG)具备优良的磁光效应,是最具应用前景的磁光材料之一。研究发现,使用稀土离子对YIG薄膜进行掺杂可以有效改善其磁光性能,尤其是Bi³⁺和Ce³⁺掺杂的YIG表现出巨法拉第效应。本文首先介绍了法拉第效应原理,介绍了三种常见磁光薄膜的生长方法,回顾了近年来的主要研究成果,介绍了磁光薄膜在光隔离器和环行器中的应用,最后对磁光薄膜的未来发展趋势进行了展望。     

Studies on the syntheses of polymetalloxanes and their properties as a precursor for amorphous oxide. IV. Properties of SiO2–TiO2 oxide fibers from polytitanosiloxane

From polytitanosiloxanes (PTS), SiO₂–TiO₂ oxide fibers with fairly good tensile strength were prepared, and their mechanical and thermal properties were investigated. The precursor fibers PTS-0.5 and PTS-1.0 were obtained by dry spinning of a highly viscous PTS solution which were formed as the reaction mixture of silicic acid (SA) with bis(2,4-pentanedionato)titanium diisopropoxide (PTP) in the molar ratios (SA/PTP) of 0.5 and 1.0. The precursor fibers PTS-0.5 were too brittle to measure their tensile strength, whereas PTS-1.0 and the heat-treated fibers were found to have tensile strength of 130 (precursor), 540 (500°C), and 450 (900°C) MPa, respectively. Heat-treatment of the fibers PTS-1.0 at above 1000°C forms anatase and rutile of titanium dioxide. The crystallization is resulted from the unreacted PTP which is not incorporated into the polymer network.     

Ferroptosis: A New Road towards Cancer Management

Ferroptosis is a recently described programmed cell death mechanism that is characterized by the buildup of iron (Fe)-dependent lipid peroxides in cells and is morphologically, biochemically, and genetically distinct from other forms of cell death, having emerged to play an important role in cancer biology. Ferroptosis has significant importance during cancer treatment because of the combination of factors, including suppression of the glutathione peroxidase 4 (Gpx4), cysteine deficiency, and arachidonoyl (AA) peroxidation, which cause cells to undergo ferroptosis. However, the physiological significance of ferroptosis throughout development is still not fully understood. This current review is focused on the factors and molecular mechanisms with the diagrammatic illustrations of ferroptosis that have a role in the initiation and sensitivity of ferroptosis in various malignancies. This knowledge will open a new road for research in oncology and cancer management.     

NO in Viral Infections: Role and Development of Antiviral Therapies

Nitric oxide is a ubiquitous signaling radical that influences critical body functions. Its importance in the cardiovascular system and the innate immune response to bacterial and viral infections has been extensively investigated. The overproduction of NO is an early component of viral infections, including those affecting the respiratory tract. The production of high levels of NO is due to the overexpression of NO biosynthesis by inducible NO synthase (iNOS), which is involved in viral clearance. The development of NO-based antiviral therapies, particularly gaseous NO inhalation and NO-donors, has proven to be an excellent antiviral therapeutic strategy. The aim of this review is to systematically examine the multiple research studies that have been carried out to elucidate the role of NO in viral infections and to comprehensively describe the NO-based antiviral strategies that have been developed thus far. Particular attention has been paid to the potential mechanisms of NO and its clinical use in the prevention and therapy of COVID-19.