Formation mechanism of CaCO3 spherulites in myostracum layer of limpet sahells

The authors would like to thank EPSRC for financial support on FEG-SEM equipment (EP/F019580/1) and FEI Scios dualbeam microscope (EP/L017008/01).CaCO3 spherulites were found in the myostracum layer of common limpet shells collected from East Sands, St Andrews, Scotland. Their microstructures were revealed by using powder X- ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, and energy dispersive X-ray microanalysis. The formation mechanisms of these spherulites and their morphology evolution were postulated. It was proposed that spherical particles of an inorganic and biological composite formed first. In the centre of each spherical particle was developed a double-layer disk of vaterite crystal sandwiching a biological sheet. The disk crystal supplies a relatively strong mirror symmetric dipole filed, guiding the orientations of the nanocrystallites and the arrangement of mesorods, and therefore, determining the final morphology of the spherulite.Publisher PDFPeer reviewe

Formation, crystal growth and colour appearance of Mimetic Tianmu glaze

WZZ thanks EPSRC for financial support on FEG-SEM equipment (EP/F019580/1).Mimetic Tianmu glaze has been synthesized and analysed by using X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy and transmission electron microscopy. It was found that the main body of the glaze was amorphous aluminium silicate with many embedded polycrystalline spherical particles of metal oxides containing manganese, cobalt, vanadium, bismuth and tungsten. Two dimensional spinel dendrites crystals of manganese, cobalt and aluminium oxide formed on the surface of the glaze. The formation mechanism of the microstructures in the Tianmu glaze is proposed. The colour appearance of the glaze has also been discussed. It has been found that the crystal thickness dependant light interference could be an important factor for the appearance of rainbow-like colour in the glaze layer.PostprintPeer reviewe

Direct growth of SnO2 nanocrystallites on electrochemically exfoliated graphene for lithium storage

This work was financially supported by National Natural Science Foundation of China (21573023). WZ thanks EPSRC’s support to the electron microscopy Laboratory for a Capital Equipment Grant EP/L017008/1.As a new generation of high quality graphene, electrochemically exfoliated graphene is an ideal platform for constructing integrated high-performance nanocomposites as advanced electrode materials for energy storage and conversion devices. To take on a challenge of direct growth of nanoparticles on electrochemically exfoliated graphene with limited oxygen-containing functional groups and its hydrophobic nature, a systematic study is carried out on growth of SnO2 nanocrystallites on the surface of electrochemically exfoliated graphene. The results indicate that these nanocrystals can efficiently grow on the functional group-free surface of electrochemically exfoliated graphene, if the precursor molecules can polymerize into larger molecules and aggregate on electrochemically exfoliated graphene followed by decomposition and phase transformation into the final metal oxide nanocrystallites. Some key factors affecting this non-classical crystal growth are investigated. Addition of a small amount of water in a polar aprotic solvent to stimulate polymerization of the precursor molecules and a solvothermal treatment to facilitate decomposition of the disordered aggregates of the polymerized precursors are crucial to the growth of nanocrystals on electrochemically exfoliated graphene. The improved electrical conductivity and structural stability of the hybrids may promote the performance of the materials in various applications, such as exceptional lithium storage capability.PostprintPeer reviewe

Drosophila eyes absent is a Novel mRNA Target of the Tristetraprolin (TTP) Protein DTIS11

The Tristetraprolin (TTP) protein family includes four mammalian members (TTP, TIS11b, TIS11d, and ZFP36L3), but only one in Drosophila melanogaster (DTIS11). These proteins bind target mRNAs with AU-rich elements (AREs) via two C3H zinc finger domains and destabilize the mRNAs. We found that overexpression of mouse TIS11b or DTIS11 in the Drosophila retina dramatically reduced eye size, similar to the phenotype of eyes absent (eya) mutants. The eya transcript is one of many ARE-containing mRNAs in Drosophila. We showed that TIS11b reduced levels of eya mRNA in vivo. In addition, overexpression of Eya rescued the TIS11b overexpression phenotype. RNA pull-down and luciferase reporter analyses demonstrated that the DTIS11 RNA-binding domain is required for DTIS11 to bind the eya 3′ UTR and reduce levels of eya mRNA. Moreover, ectopic expression of DTIS11 in Drosophila S2 cells decreased levels of eya mRNA and reduced cell viability. Consistent with these results, TTP proteins overexpressed in MCF7 human breast cancer cells were associated with eya homologue 2 (EYA2) mRNA, and caused a decrease in EYA2 mRNA stability and cell viability. Our results suggest that eya mRNA is a target of TTP proteins, and that downregulation of EYA by TTP may lead to reduced cell viability in Drosophila and human cells

Highly efficient synthesis of LTA-type aluminophosphate molecular sieve by improved ionothermal method

This work was supported by the National Natural Science Foundation of China (Grant No. 21306072, 21203081) and Development Program of Lanzhou University of Technology for excellent teachers (Grant No. Q201113). WZ thanks EPSRC for financial support to upgrade the SEM facilities (No. EP/F019580/1). We cordially thank the Reviewers and Editors for providing us with valuable comments and suggestions.LTA-type aluminophosphate molecular sieve has been successfully synthesized by improvedionothermal method from a gel containing low-dosage ionic liquids. The optimum syntheticconditions of this material are refined. The resultant LTA molecular sieves were characterized byXRD, SEM, TG-DTA, CHN elemental analysis, solution 13C NMR, EDX, TEM and N2physisorption. The composition of the resulting LTA-type molecular sieves is determined to be(Al12P12O48)(C4H9NO)2(C8H15N2+)2(F-)2, for which morpholine together with1-butyl-3-methylimidazolium cations act as the structure-directing agent. The high zeolite yield, as well as the high specific surface area and micropore volume for the calcined LTA-type materials imply that these zeolitic materials have a high potential in applications.PostprintPeer reviewe

LACMA: Language-Aligning Contrastive Learning with Meta-Actions for Embodied Instruction Following

End-to-end Transformers have demonstrated an impressive success rate for Embodied Instruction Following when the environment has been seen in training. However, they tend to struggle when deployed in an unseen environment. This lack of generalizability is due to the agent's insensitivity to subtle changes in natural language instructions. To mitigate this issue, we propose explicitly aligning the agent's hidden states with the instructions via contrastive learning. Nevertheless, the semantic gap between high-level language instructions and the agent's low-level action space remains an obstacle. Therefore, we further introduce a novel concept of meta-actions to bridge the gap. Meta-actions are ubiquitous action patterns that can be parsed from the original action sequence. These patterns represent higher-level semantics that are intuitively aligned closer to the instructions. When meta-actions are applied as additional training signals, the agent generalizes better to unseen environments. Compared to a strong multi-modal Transformer baseline, we achieve a significant 4.5% absolute gain in success rate in unseen environments of ALFRED Embodied Instruction Following. Additional analysis shows that the contrastive objective and meta-actions are complementary in achieving the best results, and the resulting agent better aligns its states with corresponding instructions, making it more suitable for real-world embodied agents. The code is available at: https://github.com/joeyy5588/LACMA.Comment: EMNLP 202

In-situ strain tuning of the Dirac surface states in Bi2Se3 films

Elastic strain has the potential for a controlled manipulation of the band gap and spin-polarized Dirac states of topological materials, which can lead to pseudo-magnetic-field effects, helical flat bands and topological phase transitions. However, practical realization of these exotic phenomena is challenging and yet to be achieved. Here, we show that the Dirac surface states of the topological insulator Bi2Se3 can be reversibly tuned by an externally applied elastic strain. Performing in-situ x-ray diffraction and in-situ angle-resolved photoemission spectroscopy measurements during tensile testing of epitaxial Bi2Se3 films bonded onto a flexible substrate, we demonstrate elastic strains of up to 2.1% and quantify the resulting reversible changes in the topological surface state. Our study establishes the functional relationship between the lattice and electronic structures of Bi2Se3 and, more generally, demonstrates a new route toward momentum-resolved mapping of strain-induced band structure changes

Isoflavones prevent bone loss following ovariectomy in young adult rats

Soy protein, a rich source of phytoestrogens, exhibit estrogen-type bioactivity. The purpose of this study was to determine if ingestion of isoflavones before ovariectomy can prevent bone loss following ovariectomy. Twenty-four nulliparous Wistar rats were randomly divided into four groups. In the normal diet groups, a sham operation was performed on Group A, while ovariectomy was performed on Group B. For Groups C and D, all rats were fed with an isoflavone-rich (25 mg/day) diet for one month, then bilateral ovariectomy were performed. In the rats in Group C, a normal diet was begun following the ovariectomy. The rats in Groups D continued to receive the isoflavone-rich diet for two additional months postoperatively. All rats were sacrificed 60 days after surgery. The weight of bone ash of the long bones and whole lumbar spine were determined. A histological study of cancellous bone was done and biochemical indices of skeletal metabolism were performed and analyzed. The markers of bone metabolism exhibited no significant changes. When compared with the sham-operated rats fed a normal diet, the bone mass of ovariectomized rats decreased significantly; pre-ovariectomy ingestion of an isoflavone-rich diet did not prevent bone loss. The bone mass of rats treated with an isoflavone-rich diet for three months was higher than controls two months after ovariectomy