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Continuous alumina fibers with excellent thermal stability are essential in high-temperature applications. In this study, 0~1 wt% Y0.5Er0.5Ho0.5Yb0.5O3 were added to the alumina fibers to enhance thermal stability. The impact of Y0.5Er0.5Ho0.5Yb0.5O3 addition on alumina fibers' transformation and microstructure evolution of during the sintering process was systematically studied. The influence of single- and two-step sintering processes on the fiber microstructures was elucidated. The results suggested that adding Y0.5Er0.5Ho0.5Yb0.5O3 impeded fiber densification, inhibited alumina grain growth, and enhanced the thermal stability of fibers. Using a two-step sintering process facilitated the achievement of fully dense alumina fibers with fine grains. The alumina fibers added with 1.0 wt% Y0.5Er0.5Ho0.5Yb0.5O3 exhibited a remarkable strength retention rate of up to 93% after exposure to 1200 °C for 10 h. The TEM analysis revealed that rare earth elements segregation at α-Al2O3 grain boundaries due to their larger radius than the Al element contributed to stabilizing the microstructures of α-Al2O3 fibers at high service temperature. Highlights: The addition of Y0.5Er0.5Ho0.5Yb0.5O3 impeded fiber densification, inhibited alumina grain growth. After being held at 1200 °C for 10 h, the strength retention rate of alumina fiber with 1 wt% Y0.5Er0.5Ho0.5Yb0.5O3 is about 93%. Rare earth elements segregate at the grain boundary of alumina fiber, stabilizing the size of fine α-Al2O3 grains. [ABSTRACT FROM AUTHOR]

Increasing environmental genotoxic chemicals have been shown to induce epigenetic alterations. However, the interaction between genetics and epigenetics in chemical carcinogenesis is still not fully understood. Here, we constructed an in vitro human lung carcinogenesis model (16HBE-T) by treating human bronchial epithelial cells with a typical significant carcinogen benzo(a)pyrene (BaP). We identified a novel circular RNA, circ0087385, which was overexpressed in 16HBE-T and human lung cancer cell lines, as well as in lung cancer tissues and serum exosomes from lung cancer patients. The upregulated circ0087385 after exposure to BaP promoted DNA damage in the early stage of chemical carcinogenesis and affected the cell cycle, proliferation, and apoptosis of the malignantly transformed cells. Overexpression of circ0087385 enhanced the expression of cytochrome P450 1A1 (CYP1A1), which is crucial for metabolically activating BaP. Interfering with circ0087385 or CYP1A1 reduced the levels of ultimate carcinogen benzo(a)pyrene diol epoxide (BPDE) and BPDE-DNA adducts. Interfering with CYP1A1 partially reversed the DNA damage induced by high expression of circ0087385, as well as decreased the level of BPDE and BPDE-DNA adducts. These findings provide novel insights into the interaction between epigenetics and genetics in chemical carcinogenesis which are crucial for understanding the epigenetic and genetic toxicity of chemicals. [ABSTRACT FROM AUTHOR]

The preparation of precursor sol is the first and crucial step in fabricating oxide fibers by the sol–gel method. In this study, different aluminum-silica sols were prepared by adjusting the alumina and silica source mixing procedure using aluminum carboxylate sol and tetraethoxysilane (TEOS) as the aluminum source and silicon source, respectively. Continuous alumina-mullite precursor fibers were obtained by dry spinning and the effects of alumina and silica source mixing procedure on the phase transition and microstructure evolution of alumina-mullite composite fibers were investigated. The results showed that the mullite formation temperature in the fibers obtained by adding TEOS during the preparation of aluminum carboxylate sol was about 1300 °C, while it was 800 °C in the fibers obtained by mixing aluminum carboxylate sol and TEOS. In addition, the grain size of the fibers obtained by adding TEOS during the preparation of aluminum carboxylate sol was significantly smaller than that obtained by mixing aluminum carboxylate sol and TEOS. The mechanism of this difference was that the aluminum-silica sol obtained by adding TEOS during the preparation of aluminum carboxylate sol was a diphasic sol, while the aluminum-silica sol obtained by adding TEOS in the prepared aluminum carboxylate sol was a monophasic sol. Highlights: Different alumina-mullite fibers precursor sols were prepared by adjusting the alumina and silica source mixing procedures. The phase transformation and microstructural evolution of alumina-mullite composite fibers obtained by different alumina and silica source mixing procedures were investigated systematically. The grain size of the fibers obtained by adding TEOS during the preparation of aluminum carboxylate sol was significantly smaller than that obtained by mixing aluminum carboxylate sol and TEOS. [ABSTRACT FROM AUTHOR]

Inhalation of carbon black nanoparticles (CBNPs) can impair lung tissue and cause DNA damage, but the epigenetic mechanism responsible for these effects is still unclear. We explored the role of circular RNAs (circRNAs) in DNA damage induced by CBNPs in the lung. Human bronchial epithelial cell lines (16HBE and BEAS-2B) were treated with 0, 5, 10, 20, 40, or 80 μg/ml CBNPs for 24, 48, and 72 h, and BALB/c mice were exposed to 8 and 80 μg/d CBNPs for 14 days to establish in vitro and vivo models of CBNP exposure, respectively. We found that CBNPs caused DNA double-strand breaks in the lung. Using high-throughput sequencing and quantitative real-time PCR to identify CBNP-related circRNAs, we identified a novel circRNA (circ_0089282) that was overexpressed in the CBNP-exposed group. We used gain-/loss-of-function approaches, RNA pulldown assays, and silver staining to explore the regulatory function of circ_0089282 and its interactions with targeted proteins. We found that circ_0089282 interference could increase CBNP-induced DNA damage, whereas overexpression resulted in the opposite. Circ_0089282 could directly bind to the fused in sarcoma (FUS) protein and positively regulate downstream DNA repair protein DNA ligase 4 (LIG4) through FUS. This regulatory effect of circRNA on DNA damage via promotion of LIG4 illustrated the interactions between genetics and epigenetics in toxicology. [ABSTRACT FROM AUTHOR]

Controlling the density and the nanograin size is challenging but essential to prepare continuous alumina fibers with excellent performance. In this study, the continuous alumina fibers were prepared using the sol-gel method. The fibers calcined under different conditions were characterized to reveal the effect of calcining conditions on the fiber microstructure evolution. The results show that the phase transformation from amorphous Al2O3 to γ-Al2O3 and then to α-Al2O3 takes place during the calcining process. The fiber, prepared using a single-step calcining method, cannot obtain a fully dense and nanocrystal microstructure through optimizing the calcination conditions. Thus, a novel two-step calcining process was proposed, through which an almost fully dense α-Al2O3 fiber with an average grain size of ~150 nm was prepared and the tensile strength of fibers reaches 2.2 GPa. Based on the results, the effect mechanism of residual organics, phase transformation, densifying, and grain growth on the fiber microstructure evolution was discussed in depth. Highlights: The full dense alumina fiber with nanograins were prepared using a novel two-step calcination. The tensile strength of alumina fibers reaches up to 2.2 GPa. The influencing mechanism of organics removal, phase transformation, grain growth, and densification on the microstructure regulation of alumina fibers was revealed. [ABSTRACT FROM AUTHOR]

Due to the lack of relevant in situ characterization techniques, the investigation of aluminum sol–gel progress is lacking. In this study, combined with molecular dynamics simulation and conventional experimental methods, the microstructures, rheological properties, and gelation process of the carboxylic aluminum sol system were studied. The experimental results showed that, with the increase in solid content, the microstructure of the colloid developed from a loose and porous framework to a homogeneous and compact structure. The viscosity of aluminum sol decreased significantly with the increase in temperature, and a temperature above 318 k was more conducive to improving the fluidity. The simulation results show that the increase in free volume and the connectivity of pores in colloidal framework structure were the key factors to improve fluidity. In addition, free water molecules had a higher migration rate, which could assist the rotation and rearrangement of macromolecular chains and also played an essential role in improving fluidity. The Molecular dynamics simulation (MD) results were consistent with experimental results and broaden the scope of experimental research, providing necessary theoretical guidance for enhancing the spinning properties of aluminum sol. [ABSTRACT FROM AUTHOR]

Motivation Automated function prediction (AFP) of proteins is a large-scale multi-label classification problem. Two limitations of most network-based methods for AFP are (i) a single model must be trained for each species and (ii) protein sequence information is totally ignored. These limitations cause weaker performance than sequence-based methods. Thus, the challenge is how to develop a powerful network-based method for AFP to overcome these limitations. Results We propose DeepGraphGO, an end-to-end, multispecies graph neural network-based method for AFP, which makes the most of both protein sequence and high-order protein network information. Our multispecies strategy allows one single model to be trained for all species, indicating a larger number of training samples than existing methods. Extensive experiments with a large-scale dataset show that DeepGraphGO outperforms a number of competing state-of-the-art methods significantly, including DeepGOPlus and three representative network-based methods: GeneMANIA, deepNF and clusDCA. We further confirm the effectiveness of our multispecies strategy and the advantage of DeepGraphGO over so-called difficult proteins. Finally, we integrate DeepGraphGO into the state-of-the-art ensemble method, NetGO, as a component and achieve a further performance improvement. Availability and implementation https://github.com/yourh/DeepGraphGO. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Phase transformation is essentially important for the microstructures and properties of sol–gel prepared alumina fiber and powders. In this study, alumina precursor fiber and xerogels were prepared using the same aluminum carboxylate sol. The phase transformation and microstructure evolution of the precursor fibers and xerogels were investigated using TG-DSC, XRD, TEM, and SEM methods. The alumina precursor fiber and xerogels have similar chemical structures and Al(III) species. After preheated at 600 °C, most of the free water molecules, hydroxyl groups, nitrate acid radical, formic acid radicals, and acetic acid radicals are removed from the alumina precursor fiber and xerogels. The preheated fiber and xerogels exhibit amorphous phases. From the TG-DSC curves, the transformation temperature from γ-Al2O3 to α-Al2O3 in the preheated fiber is 30 °C lower than that in the preheated xerogels. The TEM results suggest that the fiber calcined at 1000 °C for 1 h can be completely transformed into α-Al2O3 phase, while the xerogels need to be calcined at 1100 °C for 1 h to completely convert into the α-Al2O3 phase. The difference in the phase transformation of the alumina fiber and xerogels was discussed in this paper. Highlights: Alumina precursor fiber and xerogels were prepared using the same aluminum carboxylate sol. The alumina precursor fiber and xerogels have similar chemical structures and Al(III) species. The preheated fiber and xerogels exhibit amorphous phases. The proportion of AlO6 units in the preheated fiber is higher than that in the preheated xerogels. The transition temperature from γ- to α-Al2O3 in the preheated fiber is 30 °C lower than the other. [ABSTRACT FROM AUTHOR]

In‐depth studies of the structure of precursor sols is very important for understanding the subsequent sol to gel transition. Here, density functional theory was applied to study the reaction of Al powder with formic and acetic acid in aqueous solution to find the structure of Al(III) complex in precursor sols. The Al3+ ion obtained by dissolving Al powder in aqueous solution of formic and acetic acid would preferentially coordinate with water molecules to form aluminum hydrates. As the reaction energy barrier of aluminum hydrates with CH3COO− and HCOO− was comparable, both aluminum formoacetate and other aluminum carboxylate monomers could be obtained. Most Al(III) complexes formed by other carboxylate monomers were similar to that prepared from aluminum formoacetate. However, some Al(III) monomers and Al(III) dimer with different structural characteristics might be detrimental to the formation of linear polymers. The formation of other aluminum carboxylate monomers had great influence on the structure of precursor sols. [ABSTRACT FROM AUTHOR]

Background: As a standardized vocabulary of phenotypic abnormalities associated with human diseases, the Human Phenotype Ontology (HPO) has been widely used by researchers to annotate phenotypes of genes/proteins. For saving the cost and time spent on experiments, many computational approaches have been proposed. They are able to alleviate the problem to some extent, but their performances are still far from satisfactory. Method: For inferring large-scale protein-phenotype associations, we propose HPOAnnotator that incorporates multiple Protein-Protein Interaction (PPI) information and the hierarchical structure of HPO. Specifically, we use a dual graph to regularize Non-negative Matrix Factorization (NMF) in a way that the information from different sources can be seamlessly integrated. In essence, HPOAnnotator solves the sparsity problem of a protein-phenotype association matrix by using a low-rank approximation. Results: By combining the hierarchical structure of HPO and co-annotations of proteins, our model can well capture the HPO semantic similarities. Moreover, graph Laplacian regularizations are imposed in the latent space so as to utilize multiple PPI networks. The performance of HPOAnnotator has been validated under cross-validation and independent test. Experimental results have shown that HPOAnnotator outperforms the competing methods significantly. Conclusions: Through extensive comparisons with the state-of-the-art methods, we conclude that the proposed HPOAnnotator is able to achieve the superior performance as a result of using a low-rank approximation with a graph regularization. It is promising in that our approach can be considered as a starting point to study more efficient matrix factorization-based algorithms. [ABSTRACT FROM AUTHOR]

In the present work, continuous mullite fibers were fabricated through the diphasic sol-gel route using aluminum isopropoxide (AIP) and aluminum nitrate (AN) as the alumina sources and colloidal silica as the silica source. Fiber processing was achieved via draw-spinning method. Amorphous inorganic mullite fibers with smooth and dense features, as well as designed chemical composition and uniform elemental distribution, were obtained by pyrolysis of the continuous precursor fibers at the ending temperature of 800 °C in air. The microstructure and mechanical properties of the samples sintered at elevated temperatures were investigated. Differential thermal analysis (DTA) showed two exothermic peaks at 978 and 1271 °C assigned to the crystallization of γ-Al2O3 and mullite phase, respectively. X-ray powder diffraction (XRD) results verified the typical phase transformation route of diphasic mullite while sintering. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed a rapid grain growth after the mullite phase had formed. As the sintering temperatures increased, the filament tensile strength of the mullite fibers first increased and then decreased, reaching a maximum value of 934 MPa at 1000 °C. Highlights: Continuous and homogeneous mullite fibers were prepared through the diphasic sol-gel route. Alumina sol fabricated by AIP and AN was used to prepare diphasic mullite sol for the first time. Smooth and dense surface remained at 900_1100 °C due to the small γ-Al2O3 grains. Rapid grain growth occurred after 1200 °C was ascribed to the formation of mullite phase. A maximum tensile strength of 934 MPa was acquired after sintering the fibers at 1000 °C. [ABSTRACT FROM AUTHOR]

In the present work, homogeneous and flexible mullite nanofibers were successfully prepared by electrospinning method through the conventional diphasic mullite sol-gel route for the first time. Alumina sol prepared using aluminum acetate (stabilized with boric acid) was mixed with colloidal silica to prepare the precursor mullite sol. Polyvinyl pyrrolidone (PVP) was applied as polymer additive. General rules for preparing desired as-spun nanofibers and fiber morphological evolution were discussed, and elemental analyses and mechanical properties of mullite nanofibers were studied. It was found that uniform as-spun nanofibers were obtained when the mass ratio of PVP solution to precursor sol was 1.5. Upon calcining, Al4B2O9 and Al18B4O33 phase formed instead of γ-Al2O3 due to the introduction of boron. Average fiber diameter decreased unceasingly with the calcination temperatures increased from 800 to 1200 °C because of the densification related to the phase transformation and the presented amorphous SiO2. After calcining at 1000 °C, relatively smooth fiber surface was obtained owing to the self-repairing ability for surface defects. Mullite nanofibers with preferable morphology possessed Al/Si molar ratio of 2.98, homogeneous elemental distribution, elastic modulus of 25.18 ± 1.29 GPa and outstanding flexibility. [ABSTRACT FROM AUTHOR]

Continuous alumina fiber exhibits excellent mechanical properties owing to its dense microstructure with fine grains. In this study, alumina fiber was prepared by the sol–gel method using iron sol as a nucleating agent. It was proposed that the α-Al2O3 grain size be adjusted based on the modification of colloidal particle size. The effect of holding temperature and reaction material ratio on the iron colloidal particle size was studied. The microstructure of alumina fiber was characterized by scanning electron microscopy (SEM). The experiment results indicated that iron colloidal particle size increases with the holding temperature and the NH4HCO3/Fe(NO3)3·9H2O ratio. The alumina fiber with uniform nano α-Al2O3 grains was obtained by calcination at 1400 °C for 5 min. The mean grain size tends to rise with the mean colloidal particle size. Using the iron sol as a nucleating agent, the fiber with a mean grain size of 22.5 nm could be formed. The tensile strength of fibers increased with the decrease of grain size. [ABSTRACT FROM AUTHOR]