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ABSTRACTThe effect of the Al content on the microstructure and mechanical behaviour of Mg–8Li–xAl–0.5Ca alloys is investigated. The experimental results show that an as-cast Mg–8Li–0.5Ca alloy is mainly composed of α-Mg, β-Li and granular Mg2Ca phases. With the addition of Al, the amount of α-Mg phase first increases and then decreases. In addition, the intermetallic compounds also obviously change. The microstructure of the test alloys is refined due to dynamic recrystallisation that occurs during extrusion. The mechanical properties of extruded alloys are much more desirable than the properties of as-cast alloys. The as-extruded Mg–8Li–6Al–0.5Ca alloy exhibits good comprehensive mechanical properties with an ultimate tensile strength of 251.2 MPa, a yield strength of 220.6 MPa and an elongation of 23.5%.

There is currently great interest in ultra-wide bandgap semiconductors for their applicability in power switching electronics with improved efficiency compared to current technologies and also to solar-blind UV detection. One of the most promising materials is Ga2O3, available in large area bulk crystals and as exfoliated nano-layers (nanobelts, nanomembranes, and nanosheets). One aspect of this material that has not been widely recognized is the sensitivity of its surface to environment. The goal of this brief focus article is to provide some insight into the mechanisms and defects that underlie this effect and explain inconsistencies in the literature.

The effect of the Al content on the microstructure and mechanical behaviour of Mg–8Li–xAl–0.5Ca alloys is investigated. The experimental results show that an as-cast Mg–8Li–0.5Ca alloy is mainly composed of a-Mg, ß-Li and granular Mg2Ca phases. With the addition of Al, the amount of a-Mg phase first increases and then decreases. In addition, the intermetallic compounds also obviously change. The microstructure of the test alloys is refined due to dynamic recrystallisation that occurs during extrusion. The mechanical properties of extruded alloys are much more desirable than the properties of as-cast alloys. The as-extruded Mg–8Li–6Al–0.5Ca alloy exhibits good comprehensive mechanical properties with an ultimate tensile strength of 251.2?MPa, a yield strength of 220.6?MPa and an elongation of 23.5%.

Tumor cells preferentially adopt aerobic glycolysis for their energy supply, a phenomenon known as the Warburg effect. It remains a matter of debate as to how the Warburg effect is regulated during tumor progression. Here, we show that CHIP (carboxyl terminus of Hsc70-interacting protein), a U-box E3 ligase, suppresses tumor progression in ovarian carcinomas by inhibiting aerobic glycolysis. While CHIP is downregulated in ovarian carcinoma, induced expression of CHIP results in significant inhibition of the tumor growth examined by in vitroand in vivoexperiments. Reciprocally, depletion of CHIP leads to promotion of tumor growth. By a SiLAD proteomics analysis, we identified pyruvate kinase isoenzyme M2 (PKM2), a critical regulator of glycolysis in tumors, as a target that CHIP mediated for degradation. Accordingly, we show that CHIP regulates PKM2 protein stability and thereafter the energy metabolic processes. Depletion or knockout of CHIP increased the glycolytic products in both tumor and mouse embryonic fibroblast cells. Simultaneously, we observed that CHIP expression inversely correlated with PKM2 levels in human ovarian carcinomas. This study reveals a mechanism that the Warburg effect is regulated by CHIP through its function as an E3 ligase, which mediates the degradation of PKM2 during tumor progression. Our findings shed new light into understanding of ovarian carcinomas and may provide a new therapeutic strategy for ovarian cancer.

Polyimide/silica (PI/silica) nanocomposite films were successfully prepared via in situdispersive polymerisation and thermal imidisation. In order to obtain homogeneous nanoscale dispersibility and good compatibility with the PI matrix, hydrophobic aerosil was selected as the nanosilica precursor. 4,4-Bis(3-aminophenoxy)biphenyl (4,3-BAPOBP) was used as diamine to improve the processability of PI. The PI/silica nanocomposite films were characterised using Fourier transform infrared spectroscopy, scanning electron microscopy and differential scanning calorimetry. The mechanical and dielectric properties of the films were also measured. The results demonstrate that the tensile strength and breakdown strength of films can be markedly improved by the addition of appropriate amounts of silica to the PI matrix. At a silica content of 4.0 wt-%, the tensile strength and the breakdown strength of the films increased by 21 and 13%, respectively, compared with the neat PI. Thus, it is feasible to use nanosilica to improve the properties of PI.

The microstructure evolution of the high carbon pearlitic steel after laser shock processing (LSP) with different laser pulse energy and high temperature annealing was investigated. After LSP, the cementite lamella were bent, fractured and broken into granules. Fragmentation and dissolution of the cementite lamella were enhanced by increasing the laser pulse energy. Results show that the ferrite lattice parameter increased due to carbon atom dissolution in the ferrite matrix, and the corresponding ferrite X-ray diffraction peaks shifted significantly towards the smaller diffraction angles. After annealing at 650°C for 30 min, an ultrafine duplex microstructure (ferrite+cementite) was formed on the surface. After LSP with a high energy, equiaxed ferrite grains were refined to 400 nm and the cementite lamella were fully spheroidised with the particle diameter of ∼150 nm. The corresponding grain size of ferrite and cementite under low pulse energy was 500 and 300 nm respectively. After annealing, the ferrite peaks significantly shifted towards the higher diffraction angles, and the ferrite lattice parameter decreased. The microhardness initially increases after LSP and then slightly decreases after subsequent annealing but remained higher than without LSP.

The microstructure evolution of the high carbon pearlitic steel after laser shock processing (LSP) with different laser pulse energy and high temperature annealing was investigated. After LSP, the cementite lamella were bent, fractured and broken into granules. Fragmentation and dissolution of the cementite lamella were enhanced by increasing the laser pulse energy. Results show that the ferrite lattice parameter increased due to carbon atom dissolution in the ferrite matrix, and the corresponding ferrite X-ray diffraction peaks shifted significantly towards the smaller diffraction angles. After annealing at 650°C for 30?min, an ultrafine duplex microstructure (ferrite+cementite) was formed on the surface. After LSP with a high energy, equiaxed ferrite grains were refined to 400?nm and the cementite lamella were fully spheroidised with the particle diameter of ~150?nm. The corresponding grain size of ferrite and cementite under low pulse energy was 500 and 300?nm respectively. After annealing, the ferrite peaks significantly shifted towards the higher diffraction angles, and the ferrite lattice parameter decreased. The microhardness initially increases after LSP and then slightly decreases after subsequent annealing but remained higher than without LSP.

Polyimide/silica (PI/silica) nanocomposite films were successfully prepared via in situdispersive polymerisation and thermal imidisation. In order to obtain homogeneous nanoscale dispersibility and good compatibility with the PI matrix, hydrophobic aerosil was selected as the nanosilica precursor. 4,4-Bis(3-aminophenoxy)biphenyl (4,3-BAPOBP) was used as diamine to improve the processability of PI. The PI/silica nanocomposite films were characterised using Fourier transform infrared spectroscopy, scanning electron microscopy and differential scanning calorimetry. The mechanical and dielectric properties of the films were also measured. The results demonstrate that the tensile strength and breakdown strength of films can be markedly improved by the addition of appropriate amounts of silica to the PI matrix. At a silica content of 4.0 wt-%, the tensile strength and the breakdown strength of the films increased by 21 and 13%, respectively, compared with the neat PI. Thus, it is feasible to use nanosilica to improve the properties of PI.

The use of tantalum as a highly effective dopant for hematite photoelectrochemistry (PEC) has shown contradictory results in previous reports. We show here through screening of different compositions by scanning electrochemical microscopy that Ta doping significantly improves the PEC performance of dropcast films on fluorine-doped tin oxide (FTO). In studies with larger electrodes, a 2% Ta-doped hematite photoanode fabricated at 500 °C shows the highest improvement of photoactivity, which is ∼32 times higher than pure hematite even under visible light. At fabrication temperature higher than 500 °C (e.g., 600, 680 °C), the substrate FTO becomes more resistive and the dopant Ta prefers to segregate from the bulk phase (α-Fe2O3) and forms tantalum fluoride oxide (TaO2F), which may act as charge-carrier recombination centers, and the corresponding Ta-doped samples show much lower photoactivities. Ta-doped hematite samples show stronger (110) diffraction as compared with the pure α-Fe2O3. We show that the doping of Ta induced a preferential growth along the {001} basal plane, which has been reported to have good conductivity. We found the conductivity of the Ta-doped hematite was improved up to at least about one order of magnitude after the incorporation of Ta, with the improved carrier mobility decreasing recombination of the photogenerated holes and electrons.

Monoclinic gallium oxide (β-Ga2O3) has recently attracted increasing attention due to the availability of high quality, large diameter single crystals from mature melt growth methods and its attractive material properties of wide EGof 4.6–4.9 eV, good electron mobility (>200 cm2/Vs) and estimated Ecof ~8 MV/cm. Compared to other ultra-wide bandgap materials, the inexpensive substrates lower the manufacturing cost for β-Ga2O3power devices. Applications of deep-UV detectors with solar blindness include inspection of high voltage transmission lines for corona and partial discharges, detection of fires and various defense systems. Si- and GaAs-based UV PDs are not truly solar-blind, as additional, bulky visible-light blocking filters are required. In this short review we discuss the use of bulk and exfoliated β-Ga2O3for these applications and relate this to the basic surface and response of the material to high temperatures, radiation exposure and typical semiconductor processing steps. The material can easily be cleaved along the (100) surface and layers with (100)A surface termination have higher energy than the (100)B termination. The (100)B cleavage plane is the favorable one, observed experimentally.

There is increasing interest in use of conducting oxide materials in new forms of transparent, flexible or wearable electronics on cheap substrates, including paper. While Si-based thin film transistors (TFTs) are widely used in displays, there are some drawbacks such as light sensitivity and light degradation and low field effect mobility (<1 cm2/Vs). For example, virtually all liquid crystal displays (LCDs) use TFTs imbedded in the panel itself. One of the promising alternatives to use of Si TFTs involves amorphous or nanocrystalline n-type oxide semiconductors. There have been promising results with zinc oxide, indium gallium oxide and zinc tin oxide channels. In this paper, recent progress in these new materials for TFTs on substrates such as paper is reviewed. In addition, InGaZnO transistor arrays show promise for driving laminar electroluminescent, organic light-emitting diode (OLED) and LCD displays. These transistors may potentially operate at up to an order of magnitude faster than Si TFTs. We have fabricated bottomgate amorphous (α-) indium-gallium-zinc-oxide (InGaZnO4) thin film transistors (TFTs) on both paper and glass substrates at low processing temperature (≤100°C). As a water and solvent barrier layer, cyclotene (BCB 3022-35 from Dow Chemical) was spin-coated on the entire paper substrate. TFTs on the paper substrates exhibited saturation mobility (μsat) of 1.2 cm2.V-1.s-1, threshold voltage (VTH) of 1.9V, subthreshold gate-voltage swing (S) of 0.65V.decade-1, and drain current onto- off ratio (ION/IOFFSubscript text) of ~104. These values were only slightly inferior to those obtained from devices on glass substrates (μsat~2.1 cm2.V-1.s-1, VTH ~0 V, S~0.74 V.decade-1, and ION/IOFF=105- 106). The uneven surface of the paper sheet led to relatively poor contact resistance between source-drain electrodes and channel layer. Future areas for development are identified.

Tantalum nitride (Ta3N5) is a promising material for photoelectrochemical (PEC) water oxidation with a narrow band gap (2.1 eV) that can effectively utilize visible light in the solar spectrum. Ta3N5nanotube (NT) arrays were synthesized on a Ta foil by electrochemical anodization followed by an ammonia treatment at 800 °C. The photocurrent of nanostructured Ta3N5was over 3 times higher than that of a dense regular Ta3N5film in 0.1 M Na2SO4aqueous solution at pH 11. Several electrocatalysts (IrO2nanoparticles (NPs), Co3O4NPs, cobalt phosphate, and Pt NPs) were used to modify Ta3N5NTs for PEC water oxidation. The photocurrent of Ta3N5NTs modified with IrO2and Co3O4was ca. four times higher than that of unmodified NTs. Cobalt phosphate also showed a positive improvement for PEC water oxidation on Ta3N5NTs, whereas Pt was ineffective. Scanning electrochemical microscopy was used to measure the faradaic efficiency of the Ta3N5photoanodes for water oxidation, which can reach as high as 88% for a Co3O4–Ta3N5NTs photoanode, but is less than 15% at best, for Ta3N5without the electrocatalyst. The results indicate that cobalt oxide and cobalt phosphate are promising candidates as electrocatalysts on Ta3N5for water oxidation because Co is an earth-abundant material.

A composite catalyst has been successfully prepared by dispersing Pt nanoparticles on a poly(o‐dihydroxybenzene) (PoDHB) modified glassy carbon (GC) electrode and characterized by SEM, EDX, and electrochemical analysis. Compared with Pt nanoparticles deposited on the bare GC, the Pt/PoDHB/GC exhibits higher catalytic activity and stronger poisoning tolerance for electro‐oxidation of methanol and formic acid. The enhanced performance could be attributed to the increase of electrochemical active surface area (EASA) arisen from the PoDHB modification. Furthermore, performance limiting factors such as platinum loading, polymer mass, H2SO4, methanol, and formic acid concentrations have been evaluated for optimizing the electrocatalytic activities.

The influences of rare earth neodymium on microstructure and mechanical properties of as cast and hot rolled AZ31B wrought magnesium alloy were investigated. The results show that the mechanical properties of both as cast and hot rolled AZ31B alloys decrease due to Nd addition. Nd reacts with Al to form Al2Nd phase when Nd is added. Bulky and brittle Al2Nd intermetallic degrades the mechanical properties. Moreover, the addition of Nd weakens the grain refining effect of Al on as cast AZ31B alloy, resulting in grain coarsening. Coarse grains also cause the decline of the mechanical properties of as cast AZ31B–Nd alloy. The negative influence of the bulky and brittle intermetallics on mechanical properties of AZ31B alloy can be relieved by large deformation because the intermetallics can be sufficiently broken up during the deformation process.

AlGaN/GaN high electron mobility transistors (HEMTs) with polar and nonpolar ZnO nanowires modified gate exhibit significant changes in channel conductance upon expose to different concentration of carbon monoxide (CO) at room temperature. The ZnO nanowires, grown by chemical vapor deposition (CVD), with perfect crystal quality will attach CO molecule and release electrons, which will lead to a change of surface charge in the gate region of the HEMTs, inducing a higher positive charge on the AlGaN surface, and increasing the piezoinduced charge density in the HEMTs channel. These electrons create an image positive charge on the gate region for the required neutrality, thus increasing the drain current of the HEMTs. The HEMTs source-drain current was highly dependent on the CO concentration. The limit of detection achieved was 400 ppm and 3200ppm in the open cavity with continuous gas flow using a 50x50m2gate sensing area for polar and nonpolar ZnO nanowire gated HEMTs sensor.

An extended displacement discontinuity method (EDDM) is proposed to analyze the stress wave propagation in jointed viscoelastic rock mass (VRM). The discontinuities in a rock mass are divided into two groups. The primary group with an average geometrical size larger than or in the same order of magnitude of wavelength of a concerned stress wave is defined as “macro-joints”, while the secondary group with a high density and relatively small geometrical size compared to the wavelength is known as “micro-defects”. The rock mass with micro-defects is modeled as an equivalent viscoelastic medium while the macro-joints in the rock mass are modeled explicitly as physical discontinuities. Viscoelastic properties of a micro-defected sedimentary rock are obtained by longitudinally impacting a cored long sedimentary rod with a pendulum. Wave propagation coefficient and dynamic viscoelastic modulus are measured. The EDDM is then successfully employed to analyze the wave propagation across macro-joint in VRM. The effect of the rock viscosity on the stress wave propagation is evaluated by comparing the results of VRM from the presented EDDM with those of an elastic rock mass (ERM) from the conventional displacement discontinuity method (CDDM). The CDDM is a special case of the EDDM under the condition that the rock viscosity is ignored. Comparison of the reflected and transmitted waves shows that the essential rock viscosity has a significant effect on stress wave attenuation. When a short propagation distance of a stress wave is considered, the results obtained from the CDDM approximate to the EDDM solutions, however, when the propagation distance is sufficiently long relative to the wavelength, the effect of rock viscosity on the stress wave propagation cannot be ignored.

A picoliter solution dispenser was used to fabric-ate photosensitizer arrays on mesoporous TiO2electrodes. The scanning electrochemical microscopy (SECM) technique, modified by replacing the usual ultramicroelectrode (UME) with an optical fiber and using the photooxidation of iodide in acetonitrile in a photoelectrochemical (PEC) cell, was shown to be useful for the initial screening of potential PEC photosensitizers. This SECM technique allows for the rapid identification of new dyes and also can be used to investigate the synergetic effect of multiple dyes for application in dye-sensitized solar cells (DSSCs). This technique was specifically demonstrated via the synthesis and analysis of a new, bis-bithiophene functionalized porphyrin derivative, wherein the modified SECM technique was used to carry out an initial test of its PEC efficiency relative to other dyes. The PEC properties of bulk films based on this new porphyrin derivative were then investigated and the results shown to be in good agreement with those obtained using the SECM method.

We report here the electrogenerated chemiluminescence (ECL) of a red fluorophore diphenylaminospirobifluorenylfumaronitrile (FPhSPFN). FPhSPFN contains two diphenylamino groups as strong electron donors at the ends linked through a nonplanar bulky spirobifluorene linker to a common fumaronitrile group as a strong electron acceptor. The cyclic voltammetry of this compound shows two one-electron transfer reduction waves and one single overall two-electron oxidation wave consisting of closely spaced waves with a peak separation of 63 mV. Chronoamperometry with an ultramicroelectrode (UME) confirmed that each reduction wave involves a 1e transfer and that the oxidation wave contains an overall 2e transfer. The first reduction wave is Nernstian, Eo1,red= −1.09 V versus SCE, and the second reduction wave, Eo2,red= −1.50 V versus SCE, produces a film on the electrode. By comparison to a digital simulation, the oxidation is assigned to two reversible, closely spaced, one-electron processes for oxidation with Eo1,ox= 1.05 V and Eo2,ox= 1.11 V versus SCE. A large wavelength shift (∼35 nm) was observed in ECL as compared to photoluminescence (PL). The ECL spectrum showed a maximum emission at 708 nm with a red-shifted shoulder at around 750 nm. ECL was studied in mixtures of benzene/acetonitrile at different composition ratios; an increase in the ratio of the ECL intensity of the shoulder with respect to the main peak emission was observed with increasing solvent polarity. ECL generated with BPO as a coreactant also showed the red-shifted shoulder at the same ratio as that with annihilation.

This experiment was conducted to determine if CLA could be transferred from sows to their offspring through the umbilical cord or milk. Eighteen pregnant Dalland sows of mixed parity were used in a completely randomized block design based on parity and BW. The sows were allotted to 1 of 3 groups and fed diets containing 0, 0.5, or 1.0% CLA during the last 50 d of gestation and throughout a 26-d lactation (n = 6). Umbilical cord blood was sampled at parturition. Colostrum and milk were collected from each sow on d 2 and 15 after farrowing. Samples of blood, backfat, and the LM were obtained from piglets at 2 and 26 d of age. Sow reproductive performance and piglet growth were not altered by CLA supplementation during the late gestation and lactation periods. The CLA supplementation of sow diets had an impact on the fatty acid profiles in colostrum and milk. Dietary CLA increased the concentrations of total SFA (linear and quadratic, P< 0.01), but reduced the total MUFA in the colostrum (linear and quadratic, P< 0.01). Although dietary CLA increased the concentrations of total SFA (quadratic, P< 0.01), it had no influence on total MUFA concentrations in the milk. In addition, feeding sows diets supplemented with CLA resulted in increases (linear and quadratic, P< 0.01) in the CLA content of plasma, backfat, and the LM in their offspring. However, trans-10, cis-12–18:2, rather than cis-9, trans-11–18:2, was detected in the umbilical cord blood, which indicates that CLA may be transported from the sow to the fetus in an isomer-specific manner.

The electrocatalytic properties of individual single Pt nanoparticles (NPs) can be studied electrochemically by measuring the current−time (i−t) responses during single NP collisions with a noncatalytic ultramicroelectrode (UME). The Pt NPs are capped with citrate ions or a self-assembled monolayer (SAM) of alkane thiols terminated with carboxylic acid that affect the observed i−tresponses. By varying the length of the SAMs or the composition of a mixed monolayer, we have studied the effect of adsorbed molecules on the catalytic activity of Pt NPs at the single particle level through electrocatalytic amplification of single NP collisions. Collisions of single NPs were triggered and recorded as individual current steps whose amplitude represents the reactivity of single Pt NPs for the reaction of interest, here hydrazine oxidation, at a given electrode potential. The catalytic properties of Pt NPs are dependent not only on the nature of the interaction between the adsorbed monolayer and the catalytic NP surface, but also on the rate of electron transfer through the SAMs, governed by their length.

Recent studies show that hydrothermally grown ZnO nanorods can modulate cell adhesion and survival on various substrates. Hydrothermal growth of ZnO nanorods on biliary stents and nitinol wires used in metal stents is demonstrated. The nanorods can be conformably coated with silicon dioxide using low temperature plasma enhanced chemical vapor deposition (PECVD) system to reduce immunogenic response. In addition, the control of nanorod density is demonstrated by using a surfactant, Triton X-100. These results show promise of using nanorod array to control cell adhesion and viability on implantable devices.

Antibody-functionalized, Au-gated AlGaN/GaN high electron mobility transistors (HEMTs) were used to detect c-erbB-2, a breast cancer marker. The antibody was anchored to the gate area through immobilized thioglycolic acid. The AlGaN/GaN HEMT drain-source current showed a rapid response of less than 5 seconds when target c-erbB-2 antigen in a buffer at clinically relevant concentrations was added to the antibody-immobilized surface. We could detect a range of concentrations from to 16.7 ug/ml to 0.25 ug/ml. These results clearly demonstrate the promise of portable electronic biological sensors based on AlGaN/GaN HEMTs for breast cancer screening.