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Iron-based composites were reinforced with TiC particulates by in situ synthesis. The microstructure was characterised by transmission electron microscope. The bright field image, dark field image and diffraction pattern of reinforcing particulates and graphite harmful phase were obtained. Meanwhile, the interface between reinforcing particulates and matrix of TiCp/Fe composite material was also observed by scanning electron microscope and transmission electron microscope. The results showed that the calculated lattice constant of reinforcing TiC particulates was 0·41 nm and the calculated lattice constants of graphite were a = 0·282 nm and c = 0·459 nm. The TiC particulates had quadrilateral morphology, and were chemically wetted in Fe matrix without distinct interface product. There was no transition layer at the interface, avoiding pollution of reinforcing particulates. This study provided some details for understanding the bonding interface of in situ metal matrix composites. [ABSTRACT FROM AUTHOR]

Hyper-IgE syndrome ( HIES) is a rare primary immunodeficiency disease characterized by eczema, recurrent staphylococcal aureus skin abscesses, pneumonia with pneumatocele formation, remarkably high serum IgE levels, eosinophilia and involvement of skeleton and connective tissues. Heterozygous signal transducer and activator of transcription 3 ( STAT3) mutations were shown to be the cause of autosomal dominant HIES ( AD- HIES). In this study, we diagnosed nine patients with HIES from 9 unrelated families on the basis of a National Institutes of Health ( NIH) score of ≥40 points, sequenced the STAT3 gene of all nine patients, and quantified Th17 cells in peripheral blood of seven patients by flow cytometry in mainland China. All nine patients had characteristic manifestation of HIES with the range of NIH scores 45-77 points. STAT3 hot mutations V637M or R382W/Q were identified in five patients. We identified two novel heterozygous missense mutations (T620S and R609G) located in Src homology 2 ( SH2) domain in two patients, respectively. In two other patients, no STAT3 mutations were found. Quantified Th17 cell numbers were markedly decreased or absent (0-0.28% of CD4+T cells) in six patients with STAT3 mutations and almost normal (0.53% of CD4+T cells) in one wild-type STAT3 patient compared with healthy controls (0.40-2.25% of CD4+T cells). These results suggest that not all patients with HIES who had NIH scores over 40 points carry STAT3 mutations, those whose Th17 cell numbers strikingly decreased probably had AD- HIES with STAT3 mutations. [ABSTRACT FROM AUTHOR]

The microstructures and resulting mechanical properties of Ti-xNb-6Zr-7·5Sn-yFe (x=24, 30, 35 and y=1, 2, 2·5 wt-%) alloys were investigated for biomedical application. The microstructures were examined by means of optical microscopy, SEM and X-ray diffraction, and Vickers hardness, compressive elastic modulus and the yield strength have been measured. X-ray diffraction analysis showed that the alloys consist of β+α or β+α+α″ phases. The volume fraction of each phase changes with the variation of Fe and Nb contents according to consulting the relation between the contents of β stabilising elements and phase composition of Ti alloys after quenching from β phase region. The different microstructures result in various mechanical properties of the alloys. Ti-24Nb-6Zr-7·5Sn-2Fe has the higher strength/modulus ratio, i.e. the lower elastic modulus and the higher yield strength; hence, it is more suitable than the other alloys for biomedical applications. [ABSTRACT FROM AUTHOR]

Ti–Si eutectic alloys with various Al contents were fabricated using vacuum arc melting. The effect of Al alloying element additions on the isothermal oxidation behaviour of Ti–Si alloys was investigated at 800°C. The oxide scales formed at different oxidation stages were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDX). The results show that Al additions appear to make the oxidation kinetics of Ti–Si eutectic alloys deviate significantly from a cubic rate expression to follow more closely parabolic kinetics. Addition of 4·9 wt-%Al significantly improves the oxidation resistance, while a lower Al content (1·8 wt-%) decreases the oxidation resistance. It was found that correct addition of aluminium increases the volume ratio of the continuous phase α-Ti in the as cast alloy, resulting in the simultaneous growth of TiO2, SiO2 and Al2O3. These oxide particles closely mix with each other to form a compact and strongly cohesive substrate for the further growth of oxide scale. It is this oxide layer that improves the oxidation resistance of the Ti–Si eutectic alloys. [ABSTRACT FROM AUTHOR]

Al2O3 particle reinforced Cu–Cr–Zr matrix composite was fabricated through a powder metallurgy plus hot extrusion route, with water atomised Cu–Cr–Zr powder as the starting materials. The electrical sliding wear property was investigated using a pin on disc type wear apparatus in air at room temperature (20°C) compared with the matrix alloy. The results show that arc erosion and mechanical wear were the dominant wear mechanism when sliding under the electrical field. The wear rates increased gradually with increasing electrical current, owing to the augment of electrical erosive degree. Incorporation of Al2O3 reinforcement increased the mechanical properties and then effectively decreased the materials loss induced by both electric arc discharge and adhesion wear. As a result, the Al2O3/Cu–Cr–Zr composite has high electrical sliding wear resistance and would be a promising candidate for the electrical sliding contact fields. [ABSTRACT FROM AUTHOR]

Owing to good antifriction properties and high wear resistance, copper hybrid composites reinforced with hard ceramic particles and solid lubricant components are regarded as promising materials for applications in sliding electrical contacts. The present work investigates the antifriction mechanism of a (SiC+Gr)/Cu composite from a microstructural viewpoint, so as to assist the development and application of this material. A graphite rich tribolayer formed on the worn surface was responsible for good tribological properties of the composites. Testing results showed that nanoparticles of graphite were involved in a mechanically mixing process by adhering to both the other wear debris and the two contacting surfaces, thereby developing a solid lubricant tribolayer. The nanographite to nanographite contacting mode, formed between the composite and the counterface, significantly improved wear resistance and friction stability. The forming and failure process of the graphite rich tribolayer was studied. A mechanism has been developed based on the experimental results. [ABSTRACT FROM AUTHOR]

The present work was undertaken to investigate the effect of sliding condition and wear surface state on the dry sliding wear behaviour of SiCp/Cu composite. Three kinds of sliding conditions, namely continuous sliding, interrupted sliding, and interrupted and cleaning sliding were employed. It was observed that a compact mechanically mixed layer (MML) was present on the worn surface of the composite, which effectively decreased the wear loss of the sliding pair. The new running in period of the interrupted tests led to breakage of the MML. Sufficient sliding and entrapment of wear debris in the contact region were two important preconditions for the formation of an MML. Therefore, continuous sliding or long period sliding is favoured to extend the life of this dry tribosystem. [ABSTRACT FROM AUTHOR]

Using the bulk g-C 3 N 4 as a precursor, four g-C 3 N 4 nanosheets were further prepared by ultrasonic, thermal, acid, and alkali exfoliation. The structures of these materials were characterized by various techniques such as X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The synergistical Fenton catalysis of these materials with Cu 2+ was evaluated by using rhodamine B as a simulated organic pollutant. The results showed that there existed a significant synergistical Fenton catalysis between Cu 2+ and g-C 3 N 4 . This synergistic effect can be observed even when the concentration of Cu 2+ was as low as 0.064 mg L -1 . The properties of g-C 3 N 4 strongly influenced the catalytic activity of the Cu 2+ /g-C 3 N 4 system. The coexistent of Cu 2+ and the alkali exfoliated g-C 3 N 4 showed the best catalytic activity. Hydroxyl radicals as oxidizing species were confirmed in the Cu 2+ /g-C 3 N 4 system by electron paramagnetic resonance spectra. The synergistic catalysis may be attributed to the easier reduction of Cu 2+ adsorbed on the g-C 3 N 4 . This study provided an excellent Fenton catalytic system, and partly solved the rapid deactivation of heterogeneous Fenton catalysts caused by the leaching of metal ions.

Graphitic carbon nitride (g-C 3 N 4 ) has attracted a large amount of research, mainly being used as a photocatalyst, but its Fenton-like catalytic performance has been overlooked. In this paper, the dark Fenton-like catalytic performance of g-C 3 N 4 was evaluated by degrading rhodamine B over a wide pH range. The results showed that the g-C 3 N 4 , which was synthesized by conventional urea pyrolysis without any modification, was an efficient metal-free heterogeneous Fenton-like catalyst. The highest activity occurred under a weakly alkaline condition of about pH 10. The experiment of catalyst recycling indicated that g-C 3 N 4 had long-term stability. The reactive oxidizing species of HO·, generated by the g-C 3 N 4 activating H 2 O 2 , was identified by EPR and further supported by a scavenging experiment of HO· using isopropanol as the scavenger. The HNO 3 oxidation of g-C 3 N 4 resulted in catalytic deactivation, implying the catalytic activity originated from the surface reduced groups of g-C 3 N 4 . The structure of synthesized g-C 3 N 4 before and after the HNO 3 oxidation was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, and a possible catalytic mechanism was proposed.

Colorectal cancer represents the fourth commonest malignancy, and constitutes a major cause of significant morbidity and mortality among other diseases. However, the chemical therapy is still under development. Angiogenesis plays an important role in colon cancer development. We developed HMQ18-22 (a novel analog of taspine) with the aim to target angiogenesis. We found that HMQ18-22 significantly reduced angiogenesis of chicken chorioallantoic membrane (CAM) and mouse colon tissue, and inhibited cell migration and tube formation as well. Then, we verified the interaction between HMQ18-22 and VEGFR2 by AlphaScreen P-VEGFR assay, screened the targets on angiogenesis by VEGF Phospho Antibody Array, validated the target by western blot and RNAi in lovo cells. We found HMQ18-22 could decrease phosphorylation of VEGFR2(Tyr(1214)), VEGFR1(Tyr(1333)), Akt(Tyr(326)), protein kinase Cα (PKCα) (Tyr(657)) and phospholipase-Cγ-1 (PLCγ-1) (Tyr(771)). Most importantly, HMQ18-22 inhibited proliferation of lovo cell and tumor growth in a human colon tumor xenografted model of athymic mice. Compared with normal lovo cells proliferation, the inhibition on proliferation of knockdown cells (VEGFR2, VEGFR1, Akt, PKCα and PLCγ-1) by HMQ18-22 decreased. These results suggested that HMQ18-22 is a novel angiogenesis inhibitor and can be a useful therapeutic candidate for colon cancer intervention.