Modulating the Verwey Transition of Epitaxial Magnetite Thin Films by Ionic Gating

Understanding the Verwey transition in magnetite (Fe3O4), a strongly correlated magnetic oxide, is a one-century-old topic that recaptures great attention because of the recent spectroscopy studies revealing its orbital details. Here, the modulation of the Verwey transition by tuning the orbital configurations with ionic gating is reported. In epitaxial magnetite thin films, the insulating Verwey state can be tuned continuously to be metallic showing that the low-temperature trimeron states can be controllably metalized by both the gate-induced oxygen vacancies and proton doping. The ionic gating can also reverse the sign of the anomalous Hall coefficient, indicating that the metallization is associated with the presence of a new type of carrier with competing spin. The variable spin orientation associated with the sign reversal is originated from the structural distortions driven by the gate-induced oxygen vacancies

A pilot study for channel catfish whole genome sequencing and de novo assembly

<p>Abstract</p> <p>Background</p> <p>Recent advances in next-generation sequencing technologies have drastically increased throughput and significantly reduced sequencing costs. However, the average read lengths in next-generation sequencing technologies are short as compared with that of traditional Sanger sequencing. The short sequence reads pose great challenges for <it>de novo </it>sequence assembly. As a pilot project for whole genome sequencing of the catfish genome, here we attempt to determine the proper sequence coverage, the proper software for assembly, and various parameters used for the assembly of a BAC physical map contig spanning approximately a million of base pairs.</p> <p>Results</p> <p>A combination of low sequence coverage of 454 and Illumina sequencing appeared to provide effective assembly as reflected by a high N50 value. Using 454 sequencing alone, a sequencing depth of 18 X was sufficient to obtain the good quality assembly, whereas a 70 X Illumina appeared to be sufficient for a good quality assembly. Additional sequencing coverage after 18 X of 454 or after 70 X of Illumina sequencing does not provide significant improvement of the assembly. Considering the cost of sequencing, a 2 X 454 sequencing, when coupled to 70 X Illumina sequencing, provided an assembly of reasonably good quality. With several software tested, Newbler with a seed length of 16 and ABySS with a K-value of 60 appear to be appropriate for the assembly of 454 reads alone and Illumina paired-end reads alone, respectively. Using both 454 and Illumina paired-end reads, a hybrid assembly strategy using Newbler for initial 454 sequence assembly, Velvet for initial Illumina sequence assembly, followed by a second step assembly using MIRA provided the best assembly of the physical map contig, resulting in 193 contigs with a N50 value of 13,123 bp.</p> <p>Conclusions</p> <p>A hybrid sequencing strategy using low sequencing depth of 454 and high sequencing depth of Illumina provided the good quality assembly with high N50 value and relatively low cost. A combination of Newbler, Velvet, and MIRA can be used to assemble the 454 sequence reads and the Illumina reads effectively. The assembled sequence can serve as a resource for comparative genome analysis. Additional long reads using the third generation sequencing platforms are needed to sequence through repetitive genome regions that should further enhance the sequence assembly.</p

CYP27A1 deficiency promoted osteoclast differentiation

Background The elevating osteoclast differentiation can lead to an imbalance in bone homeostasis, which was responsible for bone loss and bone diseases, such as osteoporosis. Multiple pathways and molecules have been involved in osteoclast formation, but the role of CYP27A1 in osteoclast differentiation has never been explored. Methods CYP27A1 deficient mice were constructed using CRISPR-Cas9 system. Osteoclast differentiation was detected by TRAP staining. Differentially expressed genes (DEGs) were identified using RNA-seq analysis and were confirmed by qRT-PCR and Western blot. Results The results showed that CYP27A1 knockout (KO) promoted osteoclast differentiation and bone loss. The transcriptomic analysis revealed that CYP27A1 KO led to differential expression of multiple genes, including ELANE, LY6C2, S100A9, GM20708, BGN, SPARC, and COL1A2, which were confirmed by qRT-PCR and Western blot. Enrichment analysis indicated that these differential genes were significantly associated with osteogenesis-related pathways, such as PPAR signaling, IL-17 signaling, and PI3K/AKT signaling, which were confirmed by qRT-PCR and Western blot. Conclusions These results suggested that CYP27A1 was involved in osteoclast differentiation, providing a novel therapeutic target for osteoclast-related diseases

Molecular Understanding of the Interfacial Interaction and Corrosion Resistance between Epoxy Adhesive and Metallic Oxides on Galvanized Steel

The epoxy adhesive-galvanized steel adhesive structure has been widely used in various industrial fields, but achieving high bonding strength and corrosion resistance is a challenge. This study examined the impact of surface oxides on the interfacial bonding performance of two types of galvanized steel with Zn–Al or Zn–Al–Mg coatings. Scanning electron microscopy and X-ray photoelectron spectroscopy analysis showed that the Zn–Al coating was covered by ZnO and Al2O3, while MgO was additionally found on the Zn–Al–Mg coating. Both coatings exhibited excellent adhesion in dry environments, but after 21 days of water soaking, the Zn–Al–Mg joint demonstrated better corrosion resistance than the Zn–Al joint. Numerical simulations revealed that metallic oxides of ZnO, Al2O3, and MgO had different adsorption preferences for the main components of the adhesive. The adhesion stress at the coating–adhesive interface was mainly due to hydrogen bonds and ionic interactions, and the theoretical adhesion stress of MgO adhesive system was higher than that of ZnO and Al2O3. The corrosion resistance of the Zn–Al–Mg adhesive interface was mainly due to the stronger corrosion resistance of the coating itself, and the lower water-related hydrogen bond content at the MgO adhesive interface. Understanding these bonding mechanisms can lead to the development of improved adhesive-galvanized steel structures with enhanced corrosion resistance

Tailoring the Olefin Selectivity in Catalytic Oxidative Dehydrogenation of Light Alkane by the Isolation Strategy

Olefins are important building blocks that have been extensively used to produce diverse consumer products in petrochemical industry. Owing to the requirement of low-carbon-footprint processes and the increasing use of light alkanes sourced from shale gas, an environmentally friendly and economic route alternative to the state-of-the-art steam cracking of crude oil has been investigated for olefin production. The oxidative dehydrogenation (ODH) of alkanes to olefins has attracted wide attention due to the absence of thermodynamic limitations and coke formation. However, excessive oxidation of olefin is prone to occur in this process. Developing a suitable ODH catalyst with high performance, particularly with enhanced selectivity, is more and more urgent but still remains a challenge. In this Review, we talk about the representative currently developed isolation strategies to optimize the selectivity of olefins via the ODH process, particularly for the conversion of ethane to ethylene, which include the dispersion regulation of metal oxide, the isolation of metal and nonmetal sites, the construction of dual functional sites to isolate dehydrogenation and oxidation steps, and the adoption of selective oxygen species with the promotion of soft oxidants as reactants. Furthermore, the mechanistic aspects about the activation of ethane and the participation of oxygen species for tailoring the selectivity are then classified and discussed in detail. Finally, the perspectives and the emerging technologies for the ODH process are listed and evaluated

FeOx Supported Single-Atom Pd Bifunctional Catalyst for Water Gas Shift Reaction

Water gas shift reaction on supported noble metal catalysts is an essential process for upgrading hydrogen source industrially. Here a series of Pd/FeOx catalysts were detected for this reaction with Pd/Al2O3 as reference. It was found that Pd/FeOx exhibited higher CO conversion than Pd/Al2O3 with a good stability even in the presence of CO2 and H-2. Along the loading decreasing, the turnover frequency of exposed Pd atoms increased with the dispersion from subnanometer (similar to 1 nm) to single atoms. Various characterizations suggested that Pd single atoms greatly enhanced the reducibility of FeOx and facilitated the formation of oxygen vacancies, which served as sites to promote the dissociation of H2O to form H-2 and atomic O. The atomic O was ready to react with the linear adsorbed CO species on Pd single-atom sites through a redox mechanism, which resulted in low activation energy of similar to 30 kJ mol(-1). (C) 2017 American Institute of Chemical Engineer

More Active Ir Subnanometer Clusters than Single-Atoms for Catalytic Oxidation of CO at Low Temperature

This work reported the adsorption and reaction performance of FeOx supported subnanometer cluster and single-atom Ir catalysts for the oxidation of CO at low temperature. By varying the pretreatment temperature and Ir loading, the single-atom and subnanometer cluster Ir catalysts were obtained. The Ir subnanometer clusters exhibited higher activity for the oxidation of CO with or without the presence of H-2 than the single-atom counterpart. By using adsorption microcalorimetry and in situ infrared spectroscopy measurements, it was found that the Ir subnanometer clusters not only promoted the adsorption and reaction of CO and O-2 but also facilitated the formation of OH species from reaction between H-2 and O-2, thus opening a new reaction pathway between CO and OH species to produce CO2 compared with that between CO and O species on the single-atom counterpart. (C) 2017 American Institute of Chemical Engineer

An Automatic Internal Wave Recognition Algorithm Based on CNN Applicable to an Ocean Data Buoy System

The application of internal wave recognition to the buoy system is of great significance to enhance the understanding of the ocean internal wave phenomenon and provide more accurate data and information support. This article proposes an automatic internal wave recognition algorithm based on convolutional neural networks (CNN), which is used in the tight-profile intelligent buoy system. The sea profile temperature data were collected using the Bailong buoy system in the Andaman Sea in 2018. The CNN network structure is applied to feature compression of ocean temperature profile data, reducing the input feature amount of the feature recognition network, thereby reducing the overall algorithm parameters and computational complexity. By adjusting the number of convolution kernels and the length of convolution steps, the original data features in the time domain and the space domain are compressed, respectively. The experimental results show that the identification accuracy and robustness of this method are clearly superior to those of other methods. Additionally, the parameter number and calculation amount of this algorithm are very tiny, which greatly improves the possibility of its deployment in the buoy system