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Corrosion Resistance and High-temperature Oxidation Behavior of Micro-arc Oxidation Ceramic Coating on High Niobium gamma-TiAl Alloy

期刊: CHINA SURFACE ENGINEERING, 2019; 32 (5)

The micro-arc oxidation (MAO) technique was used to prepare in-situ ceramic coating on the surface of high niobium gamma-TiAl alloy in sodium silicate and potassium hydroxide solution to improve the high-temperature oxidation resistance. The SEM, XRD, XPS, electrochemical workstation and box-type resistance furnace high-temperature oxidation test were used to analyze the surface and cross section morphologies, phase composition, elemental chemical bonding state, corrosion resistance and high-temperature oxidation behavior of the coating, respectively. The results of XRD and XPS show that the ceramic coating is mainly composed of Al2TiO5, SiO2 and Nb2O5. The coating has a good interface with the substrate, with a thickness of 2.15 mu m. After micro-arc oxidation treatment, the corrosion resistance of high niobium gamma-TiAl alloy in 3.5% NaCl solution is improved by nearly one order of magnitude. The oxidation weight gain of the coated sample at 800-900 degrees C is only 8.9%-37.5%. The oxidative activation energy of the uncoated sample increases from 247.79 kJ/mol to 574.41 kJ/mol for the coated sample due to the formation of the MAO coating.

Growth of U-Shaped Graphene Domains on Copper Foil by Chemical Vapor Deposition

期刊: MATERIALS, 2019; 12 (12)

U-shaped graphene domains have been prepared on a copper substrate by chemical vapor deposition (CVD), which can be precisely tuned for the shape of graphene domains by optimizing the growth parameters. The U-shaped graphene is characterized by using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman. These show that the U-shaped graphene has a smooth edge, which is beneficial to the seamless stitching of adjacent graphene domains. We also studied the morphology evolution of graphene by varying the flow rate of hydrogen. These findings are more conducive to the study of morphology evolution, nucleation, and growth of graphene domains on the copper substrate.

IF:2.97

Genetic or non-genetic prognostic factors for colon cancer classification

期刊: INTERNATIONAL JOURNAL OF COMPUTATIONAL SCIENCE AND ENGINEERING, 2019; 19 (4)

Many researches have addressed patient classification using prognostic factors or gene expression profiles (GEPs). This study tried to identify whether a prognostic factor was genetic by using GEPs. If significant GEP difference was observed between two statuses of a factor, the factor might be genetic. If the GEP difference was largely less significant than the survival difference, the survival difference might not be due to the genes; then, the factor might be non-genetic or partly non-genetic. A practice was made in this study using public dataset GSE40967, which contains GEP data of 566 colon cancer patients, messages of tumour-node-metastasis (TNM) staging, etc. Prognostic factors T, N, M, and TNM were observed being non-genetic or partly non-genetic, which should be a complement for future gene expression classifiers.

Chiral metal-organic cages/containers (MOCs): From structural and stereochemical design to applications

期刊: COORDINATION CHEMISTRY REVIEWS, 2019; 378 ()

During the past few decades, great efforts have been devoted to the design and self-assembly of discrete metal-organic cages/containers (MOCs) with increasing complexity and functionality. Among which, the incorporation of chirality into the construction of MOCs endows these supramolecular containers with unique potentials in stereochemical, nonlinear optical, biomedical and enzyme mimical fields. In this review, we give a brief survey of recent works focusing on the assembly and applications of chiral metal-organic convex polyhedra with well-defined three-dimensional (3D) outer shapes and inner cavities, including a few examples of chiral MOCs in other configurations. In general, the stereochemical origin of a chiral MOC can be generated through geometrical symmetry control pathways by removing the inherent inversion and/or mirror symmetries, in which the vertice-, edge-, and face-directed assembling approaches represent the most successful strategies to introduce stereogenic centers into and achieve absolute chiral environments in MOCs. Stereochemical memory, transfer and communication can be realized among different components of chiral MOCs in a supramolecular sense, resulting in cooperative and synergetic effects of chiral complex systems, which can be further explored for enantio-recognition, separation and asymmetric catalysis applications. (C) 2017 Elsevier B.V. All rights reserved.

IF:13.48

Beryllium Ion-Selective Phosphorescence Probes Based on 9-Crown-3 Ether Iridium Complexes

期刊: CHINESE JOURNAL OF INORGANIC CHEMISTRY, 2019; 35 (2)

Ionic iridium complex [Ir(BTZ9C3)(2)(bpy)]PF6 (1) and neutral iridium complex [Ir(BTZ9C3)(2)(f(ppz))] (2) were synthesized with 4'-(2-benzothiazolyl)benzo-9-crown-3 ether (BTZ9C3) primary ligand and different ancillary ligands: 2,2' -bipyridine (bpy) and 3-trifluoromethyl-5-(2'-pyridyl)-1,2-diazole (Hfppz). The structures of the complexes were characterized by NMR, high resolution mass spectrometry, and the single crystal structure of 1 was determined by X-ray structural analysis. All these complexes showed a strong Kelly phosphorescent emission. The photoluminescence spectra of complexes 1 and 2 in PMMA (1%(w/w)) showed emission maximum at 535 and 541 nm, respectively. Their quantum efficiencies were 10.8% and 45.0% and the luminescence lifetimes were 3.01 and 2.58 mu s. By means of the cyclic voltammogram, the HOMO levels of complexes 1 and 2 were calculated to be -5.60 and -5.35 eV. Both complexes displayed a high selectivity for Be2+ among relevant metal ions, and exhibited luminescence enhancement effect in the presence of Be2+. The stoichiometric ratio of iridium complexes responding to Be2+ was determined to be 1:2, and the detection limit is down to 6.0 mu mol.L-1. The ionic iridium complex 1 has good anti-disturbance, however the neutral iridium complex 2 is greatly interfered by Al3+. CCDC: 1844315, 1.

IF:0.8

Construction and practical application of a novel zeolite catalyst for hierarchically cracking of heavy oil

期刊: JOURNAL OF CATALYSIS, 2019; 369 ()

The conversion of the heavy fractions of crude oil into transportation fuels and chemical feedstocks is still a severe challenge for fluid catalytic cracking (FCC) technology, in which geometrical parameters of the catalyst are of key importance to the accessibility for reactant and product molecules to travel through the pore space. Here a new core-shell zeolite catalyst with hierarchical pore network from macro- via meso- to micropores is developed by controlling overgrowth of another zeolite shell on the surface of a commercial Y-zeolite. The zeolite shell is a distinctive nano ZSM-5 crystals. The core-shell zeolite catalyst has a high thermal and hydrothermal stability because of high crystallinity, which can meet the industrial requirements. More importantly, the heavy oil can be cracked by the designed zeolite catalyst step-by-step into the required products. The meso- and macroporous shell facilitates pre-cracking the large molecules in heavy oil into moderate ones which can directly diffuse into the micropores of the Y-zeolite to be cracked selectively into the desired products. Both the pore structure network and acid sites distribution of the core-shell zeolite catalyst in the FCC processing are completely harmonious. As a practical example, the catalytic cracking of VGO heavy oil is actualized over the new catalyst. The results showed that the conversion of heavy oil and the yield of gasoline increased by 1.8 wt% and 8.9 wt% respectively, LPG decreased by 6.9 wt%, iso-paraffins and olefins in gasoline fraction increased by 5.21 wt% and 6.31 wt% respectively, aromatics decreased by 11.55 wt%, because of the graduated cracking in core-shell zeolite and returned isomerization in nano ZSM-5, compared with commercially industrial FCC catalyst. (C) 2018 Elsevier Inc. All rights reserved.FCC Core-shell structure Y-zeolite Heavy oil Gradual cracking Industrialization

IF:7.72

Interfacial engineering of carbon dots with benzenediboronic acid for fluorescent biosensing

期刊: NANOSCALE ADVANCES, 2019; 1 (2)

Glucose assay is highly important in clinical diagnostics of diabetes. Herein, we engineered the surface of carbon dots by complexation with functional ligand and constructed fluorescent biosensors for the detection of hydrogen peroxide and glucose. In this study, benzenediboronic acid is conjugated to the surface of citric acid-derived carbon dots through formation of boronate complexes with the nanoparticles. The oxidation of benzenediboronic acid with hydrogen peroxide effectively quenches fluorescence of carbon dots through electron transfer process. The sensing performance of the system according to different engineered surfaces of carbon dots was studied by using carbon dots derived from various precursors and different benzenediboronic acid analogues. As a simple mix-and-detect strategy, this system is facilely applied for glucose sensing as hydrogen peroxide is the product catalyzed by glucose oxidase. The benzenediboronic acid-conjugated carbon dots derived from citric acid act as excellent optical probes for sensitive analysis of glucose with detection limit of 0.4 mu M. This sensing system shows great selectivity toward interferent species such as analogues of glucose, and can be used to determine glucose in human serum. Engineering the surface of carbon dots by complexation with ligand of interest provides a feasible way to facilitate the development of biological applications.

Chemical Protein Synthesis Enabled Mechanistic Studies on the Molecular Recognition of K27-linked Ubiquitin Chains

期刊: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 2019; 58 (9)

New synthetic strategies that exploited the strengths of both chemoselective ligation and recombinant protein expression were developed to prepare K27 di-ubiquitins (diUb), which enabled mechanistic studies on the molecular recognition of K27-linked Ubs by single-molecule Forster resonance energy transfer (smFRET) and X-ray crystallography. The results revealed that free K27 diUb adopted a compact conformation, whereas upon binding to UCHL3, K27 diUb was remodeled to an open conformation. The K27 isopeptide bond remained rigidly buried inside the diUb moiety during binding, an interesting unique structural feature that may explain the distinctive biological function of K27 Ub chains.

IF:12.26

Inhibition of breast cancer growth via miR-7 suppressing ALDH1A3 activity concomitant with decreasing breast cancer stem cell subpopulation

期刊: JOURNAL OF CELLULAR PHYSIOLOGY, 2020; 235 (2)

Breast cancer patients with high expression of aldehyde dehydrogenases (ALDHs) cell population have higher tolerability to chemotherapy since the cells posses a characteristic of breast cancer stem cells (BCSCs) that are resistant to conventional chemotherapy. In this study, we found that the ALDH-positive cells were higher in CD44(+)CD24(-) and CD44(+)CD24(-)ESA(+)BCSCs than that in both BT549 and MDA-MB-231 cell lines but microRNA-7 (miR-7) level was lower in CD44(+)CD24(-) and CD44(+)CD24(-)ESA(+)BCSCs than that in MDA-MB-231 cells. Moreover, miR-7 overexpression in MDA-MB-231 cells decreased ALDH1A3 activity by miR-7 directly binding to the 3 '-untranslated region of ALDH1A3; while the ALDH1A3 expression was downregulated in MDA-MB-231 cells, the expressions of CD44 and Epithelium Specific Antigen (ESA) were reduced along with decreasing the BCSC subpopulation. Significantly, enforced expression of miR-7 in CD44(+)CD24(-)ESA(+)BCSC markedly inhibited the BCSC-driven xenograft growth in mice by decreasing an expression of ALDH1A3. Collectively, the findings demonstrate the miR-7 inhibits breast cancer growth via suppressing ALDH1A3 activity concomitant with decreasing BCSC subpopulation. This approach may be considered for an investigation on clinical treatment of breast cancers.

Population genetic polymorphism and mutation analysis of 19 autosomal STR loci in Jiangsu Han individuals in Eastern China

期刊: ANNALS OF HUMAN BIOLOGY, 0; ()

Aim: Genetic polymorphisms and the mutation ratio of 19 autosomal short tandem repeat (STR) loci were analysed in 10,000 individuals and 7755 families from Jiangsu Province in Eastern China. Subjects and methods: Nineteen STR loci were amplified by a multiplex amplification system and genotyped on the ABI 3130 Genetic Analyser. Allele frequencies, forensic parameters and mutations for the 19 autosomal STR loci were statistically analysed. Results: In total, 344 genotypes were discovered. No significant deviation from Hardy-Weinberg equilibrium was observed. The combined power of discrimination reached 0.9999999999999999984341, and the combined probability of paternity exclusion was 0.999999989. The pairwise genetic distance and p-values between the Jiangsu and 17 published populations depended on the F-ST value calculation and are shown by the neighbour-joining evolutionary tree. No statistically significant differences were found, except for the Xinjiang Altay Han (p = 0.01802) population. The average mutation rate of the Jiangsu population across all 19 loci was 1.4 x 10(-3). The average mutation rate of the 13 core CODIS STR loci remained below 2 x 10(-3) and there was no difference and relatively high consistency (p < 0.001) by correlation coefficient analysis among the six groups. Conclusions: Allelic genetic polymorphisms and mutation data were obtained from a large number of samples, which indicated that the amplification kit is suitable for forensic application and that the Jiangsu population has its own genetic characteristics that are different from those of other ethnic populations.

The investigation into the adsorption removal of ammonium by natural and modified zeolites: kinetics, isotherms, and thermodynamics

期刊: WATER SA, 2019; 45 (4)

The objectives of this study were to modify Chinese natural zeolite by NaCl and to investigate its suitability as a low-cost clay adsorbent to remove ammonium from aqueous solution. The effect of pH on ammonium removal was investigated by batch experiments. The findings indicated that pH has a significant effect on the removal of ammonium by M-Zeo and maximum adsorption occured at pH 8. Ion exchange dominated the ammonium adsorption process at neutral pH, with the order of exchange selectivity being Na+ > Ca2+ > K+ > Mg2+. The Freundlich model provided a better description of the adsorption process than the Langmuir model. The maximum ammonium adsorption capacity was 17.83 mg/g for M-Zeo at 293K. Considering the adsorption isotherms and thermodynamic studies, the adsorption of ammonium by M-Zeo was endothermic and spontaneous chemisorption. Kinetic studies indicated that the adsorption of ammonium onto M-Zeo is well fitted by the pseudo-second-order kinetic model. E-a in the Arrhenius equation suggested the adsorption of ammonium on M-Zeo was a fast and diffusion-controlled process. The regeneration rate was 90.61% after 5 cycles. The removal of ammonium from real wastewater was carried out, and the removal efficiency was up to 99.13%. Thus, due to its cost-effectiveness and high adsorption capacity, M-Zeo has potential for use in ammonium removal from aqueous solutions.

IF:0.9

Programming DNA Nanoassembly for Enhanced Photodynamic Therapy

期刊: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 2020; 59 (5)

Photodynamic therapy (PDT) has extraordinary promise for the treatment of many cancers. However, its clinical progress is impaired by the intrinsic hypoxic tumor microenvironment that limits PDT efficacy and the safety concern associated with biological specificity of photosensitizers or vehicles. Now it is demonstrated that rationally designed DNA nanosponges can load and delivery photosensitizer effectively, target tumor precisely, and relieve hypoxia-associated resistance remarkably to enhance the efficacy of PDT. Specifically, the approach exhibits a facile assembly process, provides programmable and versatile nanocarriers, and enables robust in vitro and in vivo anti-cancer efficacy with excellent biosafety. These findings represent a practical and safe approach by designer DNA nanoassemblies to combat cancer effectively and suggest a powerful strategy for broad biomedical application of PDT.

Measuring students' moral disengagement in physical education

期刊: INTERNATIONAL JOURNAL OF SPORT PSYCHOLOGY, 2019; 50 (3)

Studies have extensively probed misbehaviors in physical education (PE), yet the psychosocial mechanisms behind such behaviors have never been discussed. The present study adopted the concept of moral disengagement by Bandura (that individuals tend to use certain psychosocial mechanisms to rationalize their misbehaviors) as a foundation. The purpose was to develop a moral disengagement scale specifically for the PE context. The items were established through interviews, and the validity and reliability of the scale were examined with a two-phase quantitative study. A five-factor (conduct reconstrual, advantageous comparison, non responsibility, distortion of consequences, and attribution of blame) and 17-item Moral Disengagement in Physical Education Scale (MDPES) was developed. The validity and reliability of the MDPES were established. The MDPES will contribute to the understanding of the psychosocial factors of students' misbehaviors in PE. Scholars, educators, or practitioners may develop strategies accordingly to restrain students' misbehaviors and meet the purpose of PE.

IF:0.66

Ultrasound-Guided Percutaneous Release of A1 Pulley by Using a Needle Knife: A Prospective Study of 41 Cases

期刊: FRONTIERS IN PHARMACOLOGY, 2019; 10 ()

Objective: The purpose of this study was to evaluate the efficacy of ultrasonography-guided percutaneous A1 pulley release with the needle knife for trigger finger. Methods: The prospective study included 21 patients (21 fingers) who underwent blind release with the needle knife and 20 patients (20 fingers) who underwent ultrasonography-guided release with the needle knife. The thickness and width of A1 pulley, clinical grade before and after release, complications, and operation time were compared between the groups. Results: The results showed that the ultrasonography-guided group had significantly better grade postoperatively and reached to 100% complete release in one time compared to the blind group (p < 0.05). Moreover, no any complications had been happened in the ultrasonography-guided group. A relatively longer operation time of the ultrasonography-guided group was observed compared to the time of the blind group. Conclusions: The needle knife is a very good tool for release of triggering fingers. Ultrasound provides a direct and precise visualization of the thickness, width and location of A1 pulley lesion. The combined use of ultrasound and the needle knife can achieve the best result for trigger finger. Moreover, the combination changes the traditional opinion and operator-dependent mode that were once widely adopted in the hospital of Chinese Medicine.

IF:3.85

miR-125b-mediated regulation of cell proliferation through the Jagged-1/Notch signaling pathway by inhibiting BRD4 expression in psoriasis

期刊: MOLECULAR MEDICINE REPORTS, 2019; 19 (6)

Psoriasis is a chronic inflammatory disease characterized by the abnormal differentiation and hyperproliferation of epidermal keratinocytes. The aim of the present study was to investigate the mechanism by which microRNA-125b (miR-125b) inhibits the activation of the bromodomain-containing protein 4 (BRD4)/Notch signaling pathway in psoriasis. The contents of associated miRNAs in serum samples from 32 patients with psoriasis were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The most significantly downregulated miRNA, miR-125b, was screened out. In experiments using HaCaT cells, the association between miR-125b and cell proliferation was observed using a Cell Counting Kit-8 assay, that between miR-125b and the Notch signaling pathway was observed by western blotting and RT-qPCR, and that between miR-125b and the upstream molecule BRD4 of the Notch signaling pathway was observed by luciferase reporter assay and western blotting. The proliferation of HaCaT cells became apparent following miR-125b inhibition. The Jagged-1 ligand in the Notch signaling pathway was upregulated, the active intracellular domain of the Notch1 receptor was increasingly truncated, and the Notch signaling pathway was activated. Furthermore, the inhibited miR-125b contributed directly toward the upstream protein BRD4 3 '-UTR of Jagged-1, ultimately activating the Notch signaling pathway with the upregulation of Jagged-1. In conclusion, the proliferation of HaCaT cells mediated by the Jagged-1/Notch signaling pathway was decreased with the miR-125b-mediated inhibition of BRD4 expression. Therefore, miR-125b may be a biomarker and potential therapeutic target for psoriasis treatment.

IF:1.85

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