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Lead selenide (PbSe) colloidal quantum dots (CQDs) are promising candidates for optoelectronic applications. To date, PbSe CQDs capped by halide ligands exhibit improved stability and solar cells using these CQDs as active layers have reported a remarkable power conversion efficiency (PCE) up to 10%. However, PbSe CQDs are more prone to oxidation, requiring delicate control over their processability and compromising their applications. Herein, an efficient strategy that addresses this issue by an in situ cation-exchange process is reported. This is achieved by a two-phase ligand exchange process where PbI

Microfluidics has made a very impressive progress in the past decades due to its unique and instinctive advantages. Droplet-based microfluidic systems show excellent compatibility with many chemical and biological reagents and are capable of performing variety of operations that can implement microreactor, complex multiple core-shell structure, and many applications in biomedical research such as drug encapsulation, targeted drug delivery systems, and multifunctionalization on carriers. Droplet-based systems have been directly used to synthesize particles and encapsulate many biological entities for biomedicine applications due to their powerful encapsulation capability and facile versatility. In this paper, we review its origin, deviation, and evolution to draw a clear future, especially for droplet-based biomedical applications. This paper will focus on droplet generation, variations and complication as starter, and logistically lead to the numerous typical applications in biomedical research. Finally, we will summarize both its challenge and future prospects relevant to its droplet-based biomedical applications.

Surface enhanced Raman spectroscopy (SERS) is a powerful optical sensing technique that can detect analytes of extremely low concentrations. However, the presence of enough SERS probes in the detection area and a close contact between analytes and SERS probes are critical for efficient acquisition of a SERS signal. Presented here is a light-powered micro/nanomotor (MNM) that can serve as an active SERS probe. The matchlike AgNW@SiO2 core-shell structure of the nanomotors work as SERS probes based on the shell-isolated enhanced Raman mechanism. The AgCl tail serves as photocatalytic nanoengine, providing a self-propulsion force by light-induced self-diffusiophoresis. The phototactic behavior was utilized to achieve enrichment of the nanomotor-based SERS probes for on-demand biochemical sensing. The results demonstrate the possibility of using photocatalytic nanomotors as active SERS probes for remote, light-controlled, and smart biochemical sensing on the micro/nanoscale.

High-performance lead-free piezoelectric ceramics 0.94(K0.45Na0.55)1−xLix(Nb0.85Ta0.15)O3–0.06AgNbO3 (KNNLTAg-x) were successfully prepared by spark plasma sintering technique. The doping effect of Li on the structural and electrical properties of KNNLTAg-x (x=0, 0.02, 0.04, 0.06, 0.08 and 0.10) ceramics was studied. The lattice structure, ferroelectric and piezoelectric properties of the KNLNTAg-x ceramics are highly dependent on the Li doping level. In particular, the Li dopant has a great impact on both Curie temperature Tc and orthorhombic-tetragonal transition temperature TO-T. The 4% Li-doped sample exhibited relatively high TO-T of 95°C, leading to a stable dynamic piezoelectric coefficient (d33*) of 220-240 pm/V in a broad temperature range from 25°C to 105°C. Additionally, the 2% Li-doped sample shows a high d33* of 320 pm/V at 135°C, suggesting its great potential for high-temperature applications.

Background Recent studies have shown that gastrokine 1 (GKN1), an important tumor suppressor gene, is downregulated in Helicobacter pylori (H. pylori) infected gastric mucosa and gastric cancer. However, the underlying mechanism is poorly understood. Herein, we investigated the potential mechanism of H. pylori-induced GKN1 downregulation. Materials and methods GKN1 and AU-rich element RNA-binding factor 1 (AUF1) expressions were assessed by quantitative real-time PCR, Western blot, or immunohistochemistry in H. pylori-infected tissues and H. pylori co-cultured cell lines. The regulation of AUF1 on GKN1 was determined by RNA pulldown assay, RNA immunoprecipitation, mRNA turnover, and luciferase activity assays. The involvement of phosphorylated extra-cellular signal-regulated kinase (p-ERK) or CagA in H. pylori-induced AUF1 expression was verified using p-ERK inhibitor or CagA knockout H. pylori. In addition, the cell proliferation and migration capacities of AUF1-knockdown cells were investigated. Results GKN1 expression progressively decreased from H. pylori-infected gastritis to gastric cancer tissues. H. pylori co-culture also induced significant GKN1 reduction in GES-1 and BGC-823 cells. Besides, the mRNA level of GKN1 and AUF1 in human gastric mucosa showed negative correlation significantly. AUF1 knockdown resulted in upregulation of GKN1 expression and promoted GKN1 mRNA decay by binding the 3' untranslated region of GKN1 mRNA H. pylori-induced AUF1 expression was associated with p-ERK activation and CagA. Furthermore, knockdown of AUF1 significantly inhibited cell viability, migration ability, and arrested fewer cells in S-phase. Conclusion Our data demonstrated that H. pylori infection downregulated GKN1 expression via the CagA/p-ERK/AUF1 pathway. AUF1 promoted gastric cancer at least partly through downregulating GKN1, which presented a novel potential target for the treatment of gastric cancer.

Encapsulation of surfactant-free Pd nanoparticles (NPs) in the metal–organic framework material ZIF-8 hollow nanospheres was achieved. Pd@ZIF-8 hollow nanospheres showed excellent size-selective catalytic properties in the liquid-phase hydrogenation of olefins. As a result of the uniform pore size of the ZIF-8 shell (apertures of 3.4 A), the catalyst showed high activity for the hydrogenation of 1-hexene (1.9×8.2 A) but very low activity for larger molecules such as cis-cyclooctene (5.3×5.5 A), trans-stilbene (4.2×11.3 A), and triphenylethylene (9.1×9.2 A). Other surfactant-free noble-metal nanoparticles could also be employed to produce NPs@MOFs for catalysis.

A miniature device for shock initiation of the hexanitrostilbene (HNS) through micro-charge detonation-driven flyer was fabricated. This device consisted of the substrate, micro-charge, flyer, and barrel. Four types of flyer (titanium of 28 μm, aluminum of 22 μm, copper of 22 μm and polyimide (PI) of 55 μm in thickness) were studied and the effect of micro-charge thickness, diameter, and barrel length were investigated by measuring the average flyer velocities using polyvinylidene fluoride (PVDF) films. The results show that the titanium flyer is more proper for such initiation device compared to aluminum, copper, and polyimide flyer. The average velocity of the flyer increased with the thickness of micro-charge and the increment was larger when the thickness increases from 0.3 mm to 0.4 mm than when the thickness increases from 0.4 mm to 0.6 mm. The flyer velocity significantly increased with the increase in the diameter of micro-charge until a plateau appeared at 0.8 mm. The flyer velocity increased first and then decreased sharply with the increase in barrel length. The average velocity for a 28 μm thick titanium flyer was measured to be as high as 2468 m s−1 when the thickness, micro-charge diameter and the length of barrel were 0.6 mm, 0.8 mm and 659 μm, respectively. The HNS-IV explosive with density 1.57 g cm−3 was initiated by this miniature device.

The desired control of size, structure, and optical properties of fluorescent carbon dots (CDs) is critical for understanding the fluorescence mechanism and exploring their potential application. Herein, a top-down strategy to chemically tailor the inexpensive coal to fluorescent CDs by a combined method of carbonization and acidic oxidation etching is reported. The size and optical properties of the as-made CDs are tuned by controlling the structures of graphitic crystallites in the starting precursor. The coal-derived CDs exhibit two different distinctive emission modes, where the intensity of the short-wavelength emission is significantly enhanced by partial reduction treatment. The evolution of the electronic structure and the surface states analysis show that two different types of fluorescence centers, nano-sized sp(2) carbon domains and surface defects, are responsible for the observed emission characteristics. The reduced CDs are demonstrated as an effective fluorescent sensing material for label-free and selective detection of Cu(II) ions with a detection limit as low as 2.0 nM, showing a great promise for real-world sensor applications.

In this paper, we propose a new sparse framework for the design of the behavioral model and digital predistorter of a broadband power amplifier (PA). We start by formulating the Volterra kernel to multidimensional memory polynomial by considering the high-order dynamic truncation of the Volterra model. Then we show how an estimate of the most significant coefficients may be obtained using a matching pursuit (MPT) algorithm by exploiting the sparsity of the model. After the indices of the nonzero coefficients are roughly estimated, the block exact Householder inverse QR-decomposition-based recursive least squares (HIQRD-RLS) algorithm is utilized to estimate the sparse model complex coefficients. For broadband nonlinear PAs, the proposed approach is demonstrated to achieve the best performance among the well-known traditional approaches in terms of in-band and out-of-band specifications. The proposed approach is also validated by evaluating the digital predistortion (DPD) performance on a Class-AB PA in terms of adjacent channel power ratio (ACPR). © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Based on hydrothermally treated phosphosilicate (SiO2–P2O5) glass and sulfonated poly(ether ether ketone) (SPEEK) polymer, perfluorosulfonate-free SiO2–P2O5/SPEEK composite membranes are prepared. The morphology, thermal and mechanical properties, pore structure, proton conductivity, water uptake, as well as the fuel cell performances of the SiO2–P2O5/SPEEK composite membranes are investigated. The SiO2–P2O5/SPEEK composite membranes with proton conductive SiO2–P2O5 glass powders of more than 50 wt.% were determined to be flexible due to the incorporation of the SPEEK polymer component, and it showed proton conductivities of above 10–2 S cm–1. A single H2/O2 fuel cell was assembled based on the SiO2–P2O5/SPEEK composite membrane, and was found to release a peak power density of 355.6 mW cm–2 at 68 °C.

A novel tetraethylenepentamine ion exchange fiber (TAIEF) was prepared using polypropylene grafted styrene (PP-g-ST) fiber as raw material. The chemical structure of TAIEF was characterized using infrared spectrum (IR) method. TAIEF had good appearance and shape after reaction in SEM images, the TGA curves revealed that both PP-g-ST fiber and acetyl PP-g-ST fiber had good thermal stability below 250 °C, and the weight loss rate of TAIEF is 9% from 50 °C to 200 °C obtained by TGA. TAIEF adsorption capacity to Fe(III) is larger than that of In(III) in the pH value 1.00 to 3.00, while the pH value is at 2.50 to 3.00, TAIEF adsorption capacity to Fe(II) and Zn(II) are smaller than that of In(III). The selective adsorption ability to Fe(III) is higher than In(III), and the selective absorptivity to In(III) is better than Fe(II) and Zn(II). The mechanism was explained of TAIEF favorable selective adsorption to In(III) and Fe(III) ions in mixed solutions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44513.

Multi-regional clinical trials have been widely used for efficient global new drug developments. Both a fixed-effect model and a random-effect model can be used for trial design and data analysis of a multi-regional clinical trial. In this paper, we first compare these two models in terms of the required sample size, type I error rate control, and the interpretability of trial results. We then apply the empirical shrinkage estimation approach based on the random-effect model to two criteria of consistency assessment of treatment effects across regions. As demonstrated in our computations, compared with the sample estimator, the shrinkage estimator of the treatment effect of an individual region borrowing information from the other regions is much closer to the estimator of the overall treatment effect, has smaller variability, and therefore provides much higher probability for demonstrating consistency. We use a multinational trial example with time to event endpoint to illustrate the application of the method. Copyright © 2012 John Wiley & Sons, Ltd.

The removal of chromium(VI) from saturated sodium chloride (NaCl) solution by strong alkaline anion-exchange fiber (SAAEF) was achieved with column experiments. Factors affecting the adsorption, such as the pH value, loading density, flow rate, and operational temperature, were investigated. The results show that Cr(VI) removal was remarkably pH dependent. The optimal operational conditions were as follows: pH value = 2.0, loading density = 0.12–0.19 g/cm3, room temperature, and flow rate = 6–12 BV/h. The SAAEF column could be regenerated completely by 2% NaOH in saturated NaCl or 2% KOH in 15% KCl as an eluent. Cr(VI) was recycled as Na2Cr2O7 and K2Cr2O7, respectively. The desorption rate of Cr(VI) reached 98.09%. The adsorption ability of the SAAEFs was stable after repeated use. Overall, the results indicate that SAAEF proved to be an effective material for the adsorption of high concentrations of Cr(VI) from a saturated NaCl solution. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A kind of adsorbent, strong alkaline anion exchange fiber loaded with zirconium strong alkaline anion exchange fiber (Zr@SAAEF) was prepared. Zr(IV) was uniformly distributed on SAAEF through chemical bonds and physical deposition. Zr@SAAEF has a decent effect on the removal of fluorine in water and scanning electron microscopy images and Fourier transform infrared spectroscopy spectrum showed that the Zr(IV) was successfully loaded on the fiber by chemical bonding. The average adsorption capacity of fluorine was 28.14 mg/g with pH ranging from 5.0 to 8.9, when fluorine solution (100 mg/L) was adsorbed by 0.1 g SAAEF, and the extent of removal exceed 96% when the adsorbent dose was 0.3 g. The adsorption isotherms were well fitted with Langmuir equation, and the maximum adsorption capacities calculated by Langmuir equation were close to the experiment results. The adsorption was an endothermic reaction. These results implied that fluorine adsorption onto Zr@SAAEF belonged to chemical adsorption using monolayer coverage on surface of the fiber. The adsorption kinetics of fluorine onto Zr@SAAEF could be described by pseudo-second-order rate mode. Zr@SAAEF showed a decent ability for fluorine removal from aqueous solution. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45855.

In this paper, the authors propose a highly conductive die attach material based on Ag@Sn powder for power devices operating at high temperatures or in other harsh environments. The preform can be reflowed at 250 °C (18 °C above the Tm of Sn, 232 °C), but the resulting bondline can sustain high temperatures up to 400 °C with a high shear strength due to the high re-melting temperature of the formed Ag3Sn (Tm = 480 °C) after the complete consumption of the outer Sn layers. In addition, the formed bondline exhibits excellent electrical and thermal conductivities due to the embedded Ag particles in the interconnections. The interconnections also exhibit excellent reliability under thermal shock cycling from −55 to 200 °C because of the increased bondline thickness and inherent ductility of the Ag particles embedded in the Ag3Sn.