Polyoxometalate-Based Nanomaterials Toward Efficient Cancer Diagnosis and Therapy

As an emerging class of inorganic metal oxides, organically functionalized polyoxometalates (POMs) or POM-based nanohybrids have been demonstrated promising potential for the inhibition of various cancer types by the virtue of their diversity in structures and significantly reduced toxicity. This contribution summarizes the latest achievement of POM-based nanomaterials in cancer diagnosis and various therapeutics to put forward our fundamental viewpoints on the design principles of modified POMs based on their application. In addition, major challenges and perspectives in this field are also discussed. We expect that this review will provide a valuable and systematic reference for the further development of POM-based nanomaterials.     

Poly(4,8‐bis(2‐ethylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene vinylene): Synthesis,optical and photovoltaic properties

A new benzodithiophene (BDT)‐based polymer, poly(4,8‐bis(2‐ethylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene vinylene) (PBDTV), was synthesized by Pd‐catalyzed Stille‐coupling method. The polymer is soluble in common organic solvents and possesses high thermal stability. PBDTV film shows a broad absorption band covering from 350 nm to 618 nm, strong photoluminescence peaked at 545 nm and high hole mobility of 4.84 × 10^?3 cm²/Vs. Photovoltaic properties of PBDTV were studied by fabricating the polymer solar cells based on PBDTV as donor and PC₇₀BM as acceptor. With the weight ratio of PBDTV: PC₇₀BM of 1:4 and the active layer thickness of 65 nm, the power conversion efficiency of the device reached 2.63% with V_oc = 0.71 V, I_sc = 6.46 mA/cm², and FF = 0.57 under the illumination of AM1.5, 100 mW/cm². © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1822–1829, 2010     

Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments

Polyurethane cationomers were synthesised in the reaction of 4,4’-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M?= 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. ¹H, ¹³C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on ¹H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss–Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m². That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions.     

Broadband Convergence of 40 GHz-ROF and 10-Gb/s WDM-PON Systems in the Duplex Access Network

A broadly converged 40G-ROF and 10-Gb/s WDM-PON multi-service access system is proposed and exper- imentally demonstrated. This scheme consists of an integrated system of 40G-ROF and 10-Gb/s WDM-PON simultaneously transmitting independent 2.5-Gb/s wireless and 10-Gb/s wire signal. At the base station, it employs a remodulation scheme, which is achieved by remodulating the upstream OOK signal on the DPSK downstream signal, to reduce the cost of the base station. The transmission experiment is carried out over a 25-km-long single mode fiber （SMF-28）. The results show that the sensitivities of downstream PON and ROF signal are -14.5 dBm and -21.5 dBm, respectively, and the sensitivity of upstream signal is -25.3 dBm.     

Structures, phase transition, elastic properties of SnO2 from first-principles analysis

We investigate the structural, phase transition and elastic properties of SnO₂ in the rutile-type, pyrite-type, ZrO₂-type and cotunnite-type phases by the plane-wave pseudopotential density functional theory method. The lattice constants, bulk modulus and its pressure derivative are well consistent with the available experimental and other theoretical data. Also, we find that the rutile→pyrite, pyrite→ZrO₂ and ZrO₂→cotunnite phase transition occur at 12.9, 59.1 and 111.1 GPa, which are in better agreement with the experimental results than those of Gracia et al. (2007). Moreover, we obtain the pressure dependences of elastic constants for the four structures.     

Monolayer Co3O4 Inverse Opals as Multifunctional Sensors for Volatile Organic Compounds

Monolayers of periodic porous Co₃O₄ inverse opal (IO) thin films for gas‐sensor applications were prepared by transferring cobalt‐solution‐dipped polystyrene (PS) monolayers onto sensor substrates and subsequent removal of the PS template by heat treatment. Monolayer Co₃O₄ IO thin films having periodic pores (d≈500 nm) showed a high response of 112.9 to 5 ppm C₂H₅OH at 200 °C with low cross‐responses to other interfering gases. Moreover, the selective detection of xylene and methyl benzenes (xylene+toluene) could be achieved simply by tuning the sensor temperature to 250 and 275 °C, respectively, so that multiple gases can be detected with a single chemiresistor. Unprecedentedly high ethanol response and temperature‐modulated control of selectivity with respect to ethanol, xylene, and methyl benzenes were attributed to the highly chemiresistive IO nanoarchitecture and to the tuned catalytic promotion of different gas‐sensing reactions, respectively. These well‐ordered porous nanostructures could have potential in the field of high‐performance gas sensors based on p‐type oxide semiconductors.     

Direct and inverse problems for electromagnetic scattering by a doubly periodic structure with a partially coated dielectric

Consider the problem of scattering of electromagnetic waves by a doubly periodic Lipschitz structure. The medium above the structure is assumed to be homogenous and lossless with a positive dielectric coefficient. Below the structure there is a perfect conductor with a partially coated dielectric boundary. We first establish the well‐posedness of the direct problem in a proper function space and then obtain a uniqueness result for the inverse problem by extending Isakov's method. Copyright © 2009 John Wiley & Sons, Ltd.