In Situ Probing and Synthetic Control of Cationic Ordering in Ni‐Rich Layered Oxide Cathodes

Ni‐rich layered oxides (LiNi_1–x M_x O₂; M = Co, Mn, …) are appealing alternatives to conventional LiCoO₂ as cathodes in Li‐ion batteries for automobile and other large‐scale applications due to their high theoretical capacity and low cost. However, preparing stoichiometric LiNi_1–x M_x O₂ with ordered layer structure and high reversible capacity, has proven difficult due to cation mixing in octahedral sites. Herein, in situ studies of synthesis reactions and the associated structural ordering in preparing LiNiO₂ and the Co‐substituted variant, LiNi_0.8Co_0.2O₂, are made, to gain insights into synthetic control of the structure and electrochemical properties of Ni‐rich layered oxides. Results from this study indicate a direct transformation of the intermediate from the rock salt structure into hexagonal phase, and during the process, Co substitution facilities the nucleation of a Co‐rich layered phase at low temperatures and subsequent growth and stabilization of solid solution Li(Ni, Co)O₂ upon further heat treatment. Optimal conditions are identified from the in situ studies and utilized to obtain stoichiometric LiNi_0.8Co_0.2O₂ that exhibits high capacity (up to 200 mA h g^?1 ) with excellent retention. The findings shed light on designing high performance Ni‐rich layered oxide cathodes through synthetic control of the structural ordering in the materials.     

Copper(II)/H(2)O(2)-mediated DNA cleavage: involvement of a copper(III) species in H-atom abstraction of deoxyribose units.

A new bis-amido-copper(II) complex 2 has been prepared. In the presence of reducing agents (ascorbate or DTT) under air atmosphere or hydrogen peroxide, complex 2 exhibited interesting nuclease activities in the 1-10 microM concentration range. For explaining the activity observed with hydrogen peroxide, we propose the occurrence of a bis-amido-copper(III) intermediate and an oxidation mechanism involving a H-atom abstraction of deoxyribose moieties of DNA.     

Nucleotide sequence of a chicken vitellogenin gene and derived amino acid sequence of the encoded yolk precursor protein

The gene encoding the major vitellogenin from chicken has been completely sequenced and its exon-intron organization has been established. The gene is 20,342 base-pairs long and contains 35 exons with a combined length of 5787 base-pairs. They encode the 1850-amino acid pre-peptide of vitellogenin, which is the precursor of the mature yolk proteins, the serine-rich and heavily phosphorylated phosvitin and the lipovitellin. The 217-amino acid phosvitin polypeptide occupies an internal position (residue 1112 through 1328) within the vitellogenin molecule. The 125,000 and 30,000 Mr lipovitellin polypeptides are encoded by the sequences at the N-terminal and the C-terminal sides of the phosvitin section, respectively. The main features of the gene and protein sequences, and the evolutionary implications, are discussed.     

香菇的学名及其在当代真菌分类中的位置

本文综述了香菇(Lentinula edodes)的分类历史,确认其在蘑菇目(Agaricales)Tricholomataceae科下的分类地位,并证实了它与多孔菌目(Poriales)Lentinaceae科的Lentinus属没有联系。根据《真菌、地衣汉语学名命名法规》,作者讨论了译为“香菇属”的Lentinus和“小香菇属”的Lentinellus两属的汉语学名问题,提出Lentinus的汉语学名应订正为“韧伞属”,Lentinellus为“螺壳菌属”。香菇所在的Lentinula属的汉语学名建议为“木菇属”。     

Effect of glucose on glycerol metabolism by Clostridium butyricum DSM 5431

The levels of 1,3-propanediol dehydrogenase and of the glycerol dehydrogenase in Clostridium butyricum grown on glucose–glycerol mixtures were similar to those found in extracts of cells grown on glycerol alone, which can explain the simultaneous glucose–glycerol consumption. On glycerol, 43% of glycerol was oxidized to organic acids to obtain energy for growth and 57% to produce 1,3-propanediol. With glucose–glycerol mixtures, glucose catabolism was used by the cells to produce energy through the acetate–butyrate production and NADH, whereas glycerol was used chiefly in the utilization of the reducing power since 92–93% of the glycerol flow was converted through the 1,3-propanediol pathway. The apparent K _ms for the glycerol dehydrogenase was 16-fold higher for the glycerol than that for the glyceraldehyde in the case of the glyceraldehyde-3-phosphate dehydrogenase and fourfold higher for the NAD⁺, providing an explanation for the shift of the glycerol flow toward 1,3-propanediol when cells were grown on glucose–glycerol mixtures.     

A new repetitive element of the CR1 family downstream of the chicken vitellogenin gene.

We have analyzed a repetitive DNA sequence found in the 3'-flanking region of the chicken vitellogenin gene. By its sequence, the repetitive DNA has been identified as a hitherto unreported member of the chicken CR1 family of repetitive elements. The CR1 sequence displays the structural characteristics of a long terminal repeat located at the 3' end of an avian retrovirus. The CR1 element lies 2.2 kb downstream of the vitellogenin gene and 'points' away from the gene rather than toward it. In this respect, this element differs from other CR1 repeats. The CR1 element is embedded in a region showing changes in chromatin structure implying a potential role for this sequence in determining the structural state of the local chromatin.     

Peptide domain involved in the interaction between membrane protein and nucleocapsid protein of SARS-associated coronavirus

Severe acute respiratory syndrome (SARS) is an emerging infectious disease associated with a novel coronavirus (CoV) that was identified and molecularly characterized in 2003. Previous studies on various coronaviruses indicate that protein-protein interactions amongst various coronavirus proteins are critical for viral assembly and morphogenesis. It is necessary to elucidate the molecular mechanism of SARS-CoV replication and rationalize the anti-SARS therapeutic intervention. In this study, we employed an in vitro GST pull-down assay to investigate the interaction between the membrane (M) and the nucleocapsid (N) proteins. Our results show that the interaction between the M and N proteins does take place in vitro. Moreover, we provide an evidence that 12 amino acids domain (194-205) in the M protein is responsible for binding to N protein. Our work will help shed light on the molecular mechanism of the virus assembly and provide valuable information pertaining to rationalization of future anti-viral strategies.     

Relief for fish stocks: oceanic fatty acids in transgenic oilseeds

Three recent reports (Baoxiu Qi et al., Amine Abbadi et al. and Anthony J. Kinney et al.) describe the production of very long-chain polyunsaturated fatty acids in transgenic plants. This might lead to a sustainable source of these valuable fatty acids for use in human food and animal feed. At present they are mainly available via consumption of fish, which is a limited and endangered resource.