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OBJECTIVES The effect of aortic haemodynamics on arterial wall properties in ascending thoracic aortic aneurysms (ATAAs) is not well understood. We aim to delineate the relationship between shear forces along the aortic wall and loco-regional biomechanical properties associated with the risk of aortic dissection. METHODS Five patients with ATAA underwent preoperative magnetic resonance angiogram and four-dimensional magnetic resonance imaging. From these scans, haemodynamic models were constructed to estimate maximum wall shear stress (WSS), maximum time-averaged WSS, average oscillating shear index and average relative residence time. Fourteen resected aortic samples from these patients underwent bi-axial tensile testing to determine energy loss (ΔUL) and elastic modulus (E10) in the longitudinal (ΔULlong, E10long) and circumferential (ΔULcirc, E10circ) directions and the anisotropic index (AI) for each parameter. Nine resected aortic samples underwent peel testing to determine the delamination strength (Sd). Haemodynamic indices were then correlated to the biomechanical properties. RESULTS A positive correlation was found between maximum WSS and ΔULlong rs=0.75, P = 0.002 and AIΔUL (rs=0.68, P=0.01). Increasing maximum time-averaged WSS was found to be associated with increasing ΔULlong (rs=0.73, P = 0.003) and AIΔUL (rs=0.62, P=0.02). Average oscillating shear index positively correlated with Sd (rs=0.73,P=0.04). No significant relationship was found between any haemodynamic index and E10, or between relative residence time and any biomechanical property. CONCLUSIONS Shear forces at the wall of ATAAs are associated with local degradation of arterial wall viscoelastic hysteresis (ΔUL) and delamination strength, a surrogate for aortic dissection. Haemodynamic indices may provide insights into aortic wall integrity, ultimately leading to novel metrics for assessing risks associated with ATAAs.

Dissection is the most common mode of failure for ascending aortic aneurysms. Currently, failure risk is assessed by measuring aortic diameter, which is insufficient as it misses many dissection patients. This motivated the search for a new biomarker that captures intrinsic tissue material properties related to failure. Energy loss is promising in this regard as it is correlated with microstructure degradation and failure of aneurysms. However, for energy loss to be used clinically, its dependency on in vivo loading conditions, which vary from patient-to-patient, must be determined. In this study, the sensitivity of energy loss to physiological strain rate, magnitude, and preload was examined. Energy loss was found to be relatively insensitive to loading conditions while maintaining a significant correlation with delamination strength as a surrogate for dissection except at low strains. These results can be used for clinical translation of in vivo measurements of energy loss to evaluate aortic dissection risk.

Two novel complexes [Fe2(μ-SC3H6S)(CO)5][Fc(PPh2)CHO] (3) and 5-{[Fe2(μ-SC3H6S)(CO)5](PPh2Fc)}-10, 15, 20-triphenylporphyrin (4), which contain ferrocene-based ligand to simulate the role of the active site of [FeFe]-hydrogenases (H-Cluster), are synthesized and characterized successfully. A graphene-mediated [FeFe]-hydrogenases biomimetic nanohybrid (TPP-NHCO-GO-[3Fe2S]) 6 is fabricated by linking organic photosensitizer tetraphenylporphyrin (TPP) and complex 3 to graphene oxide (GO) via the covalent bond. The new nanohybrid 6 is characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and inductively coupled plasma atomic emission spectrometry (ICP-AES). By comparing the ultraviolet-visible (UV-vis) absorption, fluorescence emission and time-resolved fluorescence, it can be found the efficiency of electron transfer has been obviously improved with the presence of GO, and the efficiency of electron transfer in intramolecular system is higher than that in intermolecular system. These results are also supported by the photo-induced H2 production experiments with corresponding catalytic systems in water. Besides, the cystine is used as the sacrificial electron donor for light catalytic reaction in aqueous solution, which improves the efficiency of photocatalytic H2 production compared with the common electron donors, such as ascorbic acid (H2A), triethanolamine (TEOA), glucose or Na2S2O3.

Cobalt nanoparticles supported elastic foam (Co-F) was prepared by coating commercial polyurethane foam with cobalt nanoparticle loaded hybrids (Co/rGO). The Co-F was applied to catalyze hydrolysis reaction of sodium borohydride to produce hydrogen gas. Co-F has large surface area and interconnected pores, so it showed outstanding activity in catalyzing the hydrolysis reaction and achieved a hydrogen production rate of 33.2 mL·min−1. The conditions for Co/rGO and Co-F preparation as well as reaction conditions like the reaction temperature, the concentration of NaBH4 and pH value all affected the catalytic hydrolysis of NaBH4. The Co-F could be easily recovered by taking out, pressing and rinsing in distilled water, and it exhibited almost unfaded catalytic activity in the reusage. The unique properties will make Co-F potential applications in catalytically chemical reactions.

We have synthesized cationic mesa-tetra(4-pyridyl) porphine (TPyP)-reduced graphene oxide (RGO) hybrid structures through chemical reduction and subsequent ionic self-assembly. UV–vis spectroscopy, fluorescence emission spectroscopy and scanning and transmission electron microscopies are used to analyze the structures, which indicate that TPyP covalent bonds present between the double surface of RGO sheets. A reversible on/off photo-current density of 45.89 A/cm 2 has been observed when the as-formed TPyP/RGO nanocomposite is placed in the environment of pulsed white-light illumination. In addition, an ultrasensitive electrochemical aptasensor could be fabricated by the as-prepared TPyP/RGO to detect thrombin. A linear response to thrombin has been observed with the as-formed electrochemical aptasensor in the concentration range of 1–1200 nM. Besides, the limitation of detection is determined to be 0.3 nM.

A facile and efficient approach was employed to synthesize CuFe2O4/rGO (reduced graphene oxide) nanocomposites. The morphology, crystal structure and properties of the prepared CuFe2O4/rGO nanocomposites were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction and thermo-gravimetric analysis. The CuFe2O4/rGO nanocomposites were applied as adsorbents to study their adsorption performance for Congo red. The adsorption capacity and recyclability, adsorption dynamics and adsorption models were investigated. The results show that the CuFe2O4/rGO nanocomposites are efficient and recyclable adsorbents.

CuFe2O4/reduced graphene oxide (RGO) nanostructures were fabricated by a facile chemical method, and the shape and size of the CuFe2O4 nanoparticles were tuned through changing the concentration of the reactants and the reaction temperature. The CuFe2O4/RGO nanostructures were firstly analyzed by transmission electron microscopy, Fourier Transform infrared spectroscopy and powder X-ray diffraction, and then they were exploited as magnetically recyclable catalyst for the hydrolytic dehydrogenation of NaBH4 for hydrogen evolution. They exhibited superior catalytic activity and recyclability. The calculated activation energy was 33.95 kJ mol−1, which is even lower than some metallic nanoparticle catalysts. So the CuFe2O4/RGO nanostructures will find potential applications as magnetically recyclable catalysts in hydrogen storage system for fuel cell applications.

Hydrophilic and biocompatible macromolecules were used to improve and simplify the process for the fabrication of core/shell SiO 2 @Au composite particles. The influence of polymers on the morphology of SiO 2 @Au particles with different size of SiO 2 cores was analyzed by transmission electron microscopy and scanning electron microscopy. The optical property of the SiO 2 @Au particles was studied with UV–Vis spectroscopy. The results indicate that the structure and composition of macromolecules affect the morphology of Au layers on SiO 2 microspheres. The SiO 2 @Au particles prepared in the presence of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) have thin and complete Au nanoshells owing to their inducing act in preferential growth of Au nanoparticles along the surface of SiO 2 microspheres. SiO 2 @Au particles can be also prepared from SiO 2 microspheres modified with 3-aminopropyltrimethoxysilane in the presence of PVA or PVP. This offers a simple way to fabricate a Au layer on SiO 2 or other microspheres. The SiO 2 @Au particles demonstrated high catalytic activity in the reduction of 4-nitrophenol.

Au–Pd nanoparticles were deposited on the graphene oxide (GO) nanosheets to form Au–Pd/GO nanocomposites by simultaneously reducing AuCl 4 − and PdCl 4 2− with GO without the use of any additional reductant. The Au–Pd/GO nanocomposites were used to fabricate dimensional Au–Pd/GO aerogels by a simple and green method, unidirectional freeze–drying method. The obtained Au–Pd/GO aerogel has an ordered porous architecture and shows high catalytic activity and good recyclability in a model reaction, reduction of 4-nitrophenol.

Silver nanoparticles/graphene oxide (AgNPs/GO) nanocomposites were easily fabricated by a green method without using any additional reductant and the prepared nanocomposites were then used to stabilize Pickering emulsions. The properties of the emulsions stabilized by the AgNPs/GO prepared with different AgNO3/GO mass ratios were investigated and the effects of the oil/water ratio, the AgNPs/GO concentration, and the pH on the stability, type and morphology of the emulsions were studied. In addition, the effects of adding different types and concentrations of electrolytes on the emulsion stability were studied. Adding electrolytes to the systems improved the stability of the Pickering emulsions due to the reduction in the particle zeta potentials. Polystyrene–AgNPs/GO composites were also prepared by Pickering emulsion polymerization and their catalytic performance for the reduction of 4-nitrophenol was investigated.

Graphene oxide (GO) was modified using chemical reactions to obtain three types of functionalized GO sheets (FGO). The FGO sheets and the GO were then subjected to in situ free radical polymerization in order to study the grafting polymerization. The FGO and grafted-.FGO were analyzed with Fourier transform infrared spectroscopy, scanning electronic microscopy, thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The grafting percentages in the materials were calculated using the TGA and XPS results. The FGO sheets with different functional groups exhibited different grafting abilities, and hydroxyl groups were proven to be the most reactive grafting sites for the in situ free radical grafting polymerization of polyacrylamide.

A facile and efficient approach to synthesize Fe 3 O 4 @Cu nanocomposites using l -Lysine as a linker was developed. The morphology, composition and crystallinity of the Fe 3 O 4 @Cu nanocomposites were characterized by Fourier Transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction. In addition, the magnetic properties were determined with vibrating sample magnetometer. The surface of the Fe 3 O 4 contained many small Cu nanoparticles with sizes of about 3 nm. It was found that the Fe 3 O 4 @Cu nanocomposites could catalyze the degradation of organic dyes. The catalytic activities of the Fe 3 O 4 @Cu nanocomposites for the reduction of nitrophenol were also studied. The Fe 3 O 4 @Cu nanocomposites are more efficient catalysts compared with Cu nanoparticles and can easily be recovered from the reaction mixture with magnet. The cost effective and recyclable Fe 3 O 4 @Cu nanocomposites provide an exciting new material for environmental protection applications.

A facile route for the in situ preparation of catalytically active Ni nanoparticles (NPs) in ordered macroporous hydrogel (OMH) has been developed. The hydrogel was fabricated based on polystyrene colloid template. The electronegativity of amide and carboxyl groups on the poly(acrylamide- co -acryl acid) chains of the hydrogel caused strong binding of Ni 2+ ions which made them distribute uniformly inside the hydrogel. When immersed in NaBH 4 aqueous solution, the Ni 2+ ions on the hydrogel were reduced to Ni NPs. The resultant Ni NPs loaded OMH showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with NaBH 4 . A kinetic study of the catalytic reaction was carried out. The rate constant per unit weight could reach 0.53 s −1 g −1 , which is much better than many common hydrogel loaded nickel catalysts. Moreover, the current catalyst can be easily separated and recovered with stable catalytic activity.

Gold nanoparticle/graphene oxide hybrids (AuNP/GO) were easily fabricated by a redox reaction between GO and chloroauric acid without using any additional reductant and then used to stabilize Pickering emulsions. Factors affecting the properties of the emulsions were studied, including the HAuCl4/GO mass ratio used to prepare the AuNP/GO, the oil/water ratio, the AuNP/GO concentration, the pH value, and the type and concentration of electrolytes. The emulsions were more stable when stabilized by AuNP/GO made from HAuCl4/GO mass ratios of 0.375–0.5. High pH values and AuNP/GO concentrations that were too high or too low were unfavorable to the stability of the Pickering emulsions. Adding electrolytes to the systems improved the stability of the Pickering emulsions owing to the reduction of repulsive interactions between AuNP/GO sheets. The AuNP/GO stabilized Pickering emulsions were used to prepare AuNP/GO supported polystyrene (PS) microspheres (AuNP/GO@PS) by polymerizing the Pickering emulsion. The catalytic performance of AuNP/GO@PS for the reduction of 4-nitrophenol was then studied.

A number of cadherin mutants conferring resistance to Bt toxin Cry1Ac have been reported in three major lepidopteran pests, including Helicoverpa armigera. Unlike most of the cadherin mutants conferring recessive resistance, an allele (r15) with a 55aa deletion in the intracellular domain of cadherin (HaCad) was previously identified to cause non-recessive resistance to Cry1Ac in H. armigera. In the present study, a DNA-based PCR method was developed to screen the r15 allele from field populations of H. armigera collected from the main cotton planting areas of China in 2011 and 2012. Three heterozygous r15 alleles were detected from 562 moths collected from northern China (with intensive Bt cotton planting), and r15 allele frequency was estimated to be 0.0027. However, no r15 allele was detected from 314 moths collected from Xinjiang (with limited Bt cotton use). Although all the r15 alleles have the same deletion in the cDNA sequence, at least four different indels causing loss of exon 32 have been detected in the genomic DNA sequences flanking exon 32 of HaCad. Multiple origins of the r15 alleles illustrate parallel genotypic adaption of H. armigera to the selection pressure of Bt cotton.