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Antibiotics are a kind of chief contaminants in water, which have severe effects on the environment and mortal health. The achievement of easy and promising methods for antibiotic sensing is vastly desirable but still challenging. Fast, facile, and dependable recognition of these hazardous antibiotic contaminants by luminescent probes have importance in environmental safety. Herein, we synthesized a highly luminescent cadmium-based MOF [Cd(BPDC)(BP4VA)·2DMF]n (1) using 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene (BP4VA) and biphenyl-4,4′-dicarboxylic acid (H2BPDC) as ligands. The as-prepared compound is highly stable in water within a wide range of pH (2–12). The attained LOD values up to μM level shows higher selectivity towards antibiotics. 1 exhibits attractive detection sensitivity (Ksv = 106 M−1) towards selected antibiotics among earlier reported MOF-based luminescent probes.

Terahertz (THz) technology has emerged recently as a potential novel imaging modality in biomedical fields, including ophthalmology. However, the ocular biological responses after THz electromagnetic exposure have not been investigated. We conducted a rabbit study to evaluate the safety profiles of THz scanning on eyes, at a tissue, cellular, structural and functional level. Eight animals (16 eyes) were analysed after excessive THz exposure (control, 1 h, 4 h, and 1 week after continuous 4-h exposure; THz frequency = 0.3 THz with continuous pulse generated at 40 µW). We found that at all the time points, the corneas and lens remained clear with no corneal haze or lens opacity formation clinically and histopathologically. No thermal effect, assessed by thermographer, was observed. The rod and cone cell-mediated electroretinography responses were not significantly altered, and the corneal keratocytes activity as well as endothelial viability, assessed by in-vivo confocal microscopy, was not affected. Post-exposed corneas, lens and retinas exhibited no significant changes in the mRNA expression of heat shock protein (HSP)90AB1), DNA damage inducible transcript 3 (DDIT3), and early growth response (EGR)1. These tissues were also negative for the inflammatory (CD11b), fibrotic (fibronectin and α-smooth muscle actin), stress (HSP-47) and apoptotic (TUNEL assay) responses on the immunohistochemical analyses. The optical transmittance of corneas did not change significantly, and the inter-fibrillar distances of the corneal stroma evaluated with transmission electron microscopy were not significantly altered after THz exposure. These results provide the basis for future research work on the development of THz imaging system for its application in ophthalmology. National Medical Research Council (NMRC) Published version This research was supported by the Transition Award, National Medical Research Council (R1482/65/2017), Singapore.

Rationale: Excessive Ang II (angiotensin II) levels lead to a profibrotic and hypertrophic milieu that produces deleterious remodeling and dysfunction in hypertension-associated heart failure. Agents that disrupt Ang II–induced cardiac dysfunction may have clinical utility in the treatment of hypertension-associated heart failure. Objective: We have examined the potential effect of celastrol—a bioactive compound derived from the Celastraceae family—on Ang II–induced cardiac dysfunction. Methods and Results: In rat primary cardiomyocytes and H9C2 (rat cardiomyocyte-like H9C2) cells, celastrol attenuates Ang II–induced cellular hypertrophy and fibrotic responses. Proteome microarrays, surface plasmon resonance, competitive binding assays, and molecular simulation were used to identify the molecular target of celastrol. Our data showed that celastrol directly binds to and inhibits STAT (signal transducer and activator of transcription)-3 phosphorylation and nuclear translocation. Functional tests demonstrated that the protection of celastrol is afforded through targeting STAT3. Overexpression of STAT3 dampens the effect of celastrol by partially rescuing STAT3 activity. Finally, we investigated the in vivo effect of celastrol treatment in mice challenged with Ang II and in the transverse aortic constriction model. We show that celastrol administration protected heart function in Ang II–challenged and transverse aortic constriction–challenged mice by inhibiting cardiac fibrosis and hypertrophy. Conclusions: Our studies show that celastrol inhibits Ang II–induced cardiac dysfunction by inhibiting STAT3 activity.

Two complexes, [Cu6I6(L1)3]n (I) and [Cu4I4(L2)2]n (II) (L1 = 1,4-bis(phenylthio)but-2-yne; L2 = 1,4-bis(phenylthio)butane), as precursors for thermoelectric composites were prepared using a literature procedure. During the preparation of I, an unexpected 3-D polymorph [Cu4I4(L1)2]n (1) with a triclinic space group and an infinite [CuI]n staircase structure was obtained. This new polymorph (1) exhibited the same structure at both room temperature and 173 K. Complexes 1 and II were therefore pyrolysed to composites 2 and 3, respectively, at 400 °C under a nitrogen gas flow. Composite 3 was pale in color with a low carbon content (0.05 wt%) and easily disassembled during handling. By comparison, the high carbon containing (10.2 wt%) composite 2 can be compressed into a robust, light pellet (density 3.58 g cm-3), which showed a moderate to high Seebeck coefficient (543-1308 μV K-1) over the temperature range 70-240 °C.

FeOOH has been explored as a promising adsorbent for low-temperature H 2 S adsorption. However, the nature of the active sites toward the desulfurization has remained elusive. Here, a series of γ-FeOOH is prepared with well-defined lath-like and rod-like shapes by adjusting the pH value of the reaction system. The two shapes of γ-FeOOH have identical bulk structures but expose different distributions of surface OH groups, namely singly ( FeOH, OH), doubly ( Fe 2 OH, μ OH), and triply coordinated ( Fe 3 OH, μ 3 OH) hydroxyls, allowing us to investigate the geometrical-site-dependent desulfurization activity of γ-FeOOH at molecular-scale level. Following a thorough analysis by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and in situ Fourier transform infrared spectroscopy ( In situ FT-IR), we demonstrate that singly hydroxyl ( FeOH, OH) site is responsible for H 2 S adsorption, which acts as the active site for low-temperature desulfurization.

[L2Cu4I4]n (1) based on a cubic [Cu4I4] node and ditopic, bridging bis(triazole) (L = 2,6-bis((1H-1,2,3-triazol-1-yl)methyl)pyridine) is a unique and highly symmetric cubane cluster based coordination polymer with strong yellow emission. Comparison with similar coordination polymers permits a structure activity relationship and reveals that the emission energy for these [Cu4I4] cluster-based materials occurs in the mid-range of Cu⋅⋅⋅Cu distances and tetrahedral geometry index values.

As one of the important subclasses of MOFs, Alkaline earth (group II) metal–organic frameworks (AEMOFs) in recent years also have caught much attention not only because of their fascinating structures but also because of their nontoxicity, relatively low densities, low cost and stability, etc. These merits make them have many potential applications in implementation and industrial fields. In this review, we will give a succinct description of the recent development on the AEMOFs (including the homometallic and heterometallic AEMOFs): some representative structures and physicochemical properties, such as proton conductivity, magnetism, gas or guest adsorption/separation, chromism, heterogeneous catalysis, biomedical applications, as well as luminescent sensing, are presented in this review. Fully understanding the structure–property relationship of the AEMOFs is still a long way, we hope this review could give some inspirations and help to chemists to explore the syntheses and applications of the AEMOFs in much more fields.

Pulsed terahertz (THz) broadband spectroscopy and imaging were applied to investigate ex vivo rabbit corneal scar tissues. Scars with different depths and densities were created by laser ablation on four corneal samples while two corneal samples untouched were used as control. The THz time-domain spectroscopy and reconstructed images illustrated the scar tissue density and gave out depth variation distribution profiles. Calculated absorption coefficient spectra displayed extra absorption peaks compared with control corneas and refractive index spectra showed the optical properties changed at the corneal scar locations. THz spectroscopy and imaging demonstrated adequate contrast in reviewing the scar densities and locations and showed potential applications in depicting spatial distribution and composition changes of corneal scars.

Development of the high activity, promoter-free catalysts for carbonyl sulfide (COS) hydrolysis is important for the efficient utilization of various feedstocks. In this study, the Cu-based metal-organic framework HKUST-1 is synthesized by a simple and mild anodic-dissolution electrochemical method. The physical and chemical properties of the samples are characterized by several techniques, including scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis and X-ray photoelectron spectroscopy. The results reveal that the synthesis voltage plays a crucial role in controlling the morphology of the resulting HKUST-1. The obtained samples function as novel catalysts for the hydrolysis of COS. A high efficiency, approaching 100%, can be achieved for the conversion of COS at 150 °C over the optimal HKUST-1 synthesized at 25 V. This is significantly higher than that of the sample prepared by the traditional hydrothermal method. Additionally, the effects of the water temperature and the flow velocity on the hydrolysis of COS are also investigated in detail. Finally, a possible reaction pathway of COS hydrolysis over HKUST-1 is also proposed. This work represents the first example of MOFs applied to the catalytic hydrolysis of COS. The results presented in this study can be anticipated to give a feasible impetus to design novel catalysts for removing the sulfur-containing compounds.

Owing to the unique electronic and optical properties, the graphene-like carbon nitride (C 3 N 4 ) materials have attracted widespread interest. However, the exfoliation of bulk C 3 N 4 into graphene-like structure is inhibited by the planar hydrogen bond between strands of polymeric melon units with NH/NH 2 , due to the higher electronegativity of N with respect to C atoms. Herein, graphene-like sulfur-doped C 3 N 4 (SC 3 N 4 ) samples were successfully prepared by introducing sulfur into C 3 N 4 to weaken the planar hydrogen bonding, and investigated as catalysts to photoreductively eliminate uranyl ion in aqueous media. Both experimental and computational perspectives confirmed that S-doping in SC 3 N 4 can modify its electronic structure, reflected by the elevated conduction and valence band levels, as well as the improved transportation capability of photogenerated electrons. As a result, the photoactivity for UO 2 2+ photocatalytic reduction over the optimal SC 3 N 4 was significantly improved, with apparent rate value reaching 0.16 min −1 under visible-light irradiation, which was 2.28 times that over C 3 N 4 . This study provides an effective strategy for designing efficient visible-light-responsive photocatalysts for environmental remediation.

The well-known Erzberg site represents the largest siderite (FeCO 3 ) deposit in the world. It consists of various carbonates accounting for the formation of prominent CaCO 3 (dominantly aragonite) precipitates filling vertical fractures of different width (centimetres to decimetres) and length (tens of metres). These commonly laminated precipitates are known as ‘erzbergite’. This study focuses on the growth dynamics and environmental dependencies of these vein fillings. Samples recovered on-site and from mineral collections were analyzed, and these analyses were further complemented by modern water analyses from different Erzberg sections. Isotopic signatures support meteoric water infiltration and sulphide oxidation as the principal hydrogeochemical mechanism of (Ca, Mg and Fe) carbonate host rock dissolution, mobilization and vein mineralization. Clumped isotope measurements revealed cool formation temperatures of ca 0 to 10°C for the aragonite, i.e. reflecting the elevated altitude Alpine setting, but unexpectedly low for aragonite nucleation. The 238 U– 234 U– 230 Th dating yielded ages from 285·1 ± 3·9 to 1·03 ± 0·04 kyr bp and all samples collected on-site formed after the Last Glacial Maximum. The observed CaCO 3 polymorphism is primarily controlled by the high aqueous Mg/Ca ratios resulting from dissolution of Mg-rich host rocks, with Mg/Ca further evolving during prior CaCO 3 precipitation and CO 2 outgassing in the fissured aquifer. Aragonite represents the ‘normal’ mode of erzbergite formation and most of the calcite is of diagenetic (replacing aragonite) origin. The characteristic lamination (millimetre-scale) is an original growth feature and mostly associated with the deposition of stained (Fe-rich) detrital particle layers. Broader zonations (centimetre-scale) are commonly of diagenetic origin. Petrographic observations and radiometric dating support an irregular nature for most of the layering. Open fractures resulting from fault tectonics or gravitational mass movements provide water flow routes and fresh chemical reaction surfaces of the host rock carbonates and accessory sulphides. If these prerequisites are considered, including the hydrogeochemical mechanism, modern water compositions, young U-Th ages and calculated precipitation rates, it seems unlikely that the fractures had stayed open over extended time intervals. Therefore, it is most likely that they are geologically young. Published version

The red oxide phosphors activated by Mn4+ have become a research hotspot because of their excellent physical/chemical stability, which can be applied in the field of light-emitting diodes (LED) plant growth lighting. Here, a new type of Sr9Gd2W4O24 (SGWO):Mn4+ red phosphor was prepared by traditional high temperature solid state reaction method. The phase compositions and morphologies of powders were analyzed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The luminescent properties of the samples with varying Mn4+ concentrations were investigated, and the photoluminescence excitation (PLE) spectra illustrate that samples can be effectively excited by near-ultraviolet/blue light. Furthermore, typical concentration quenching occurs when the doping concentration of Mn4+ exceeds 0.4 mol%. In addition, the thermal activation energy of the sample was calculated to be 0.3641 eV. Importantly, under the excitation of near-UV light at 365 nm, SGWO:0.004Mn4+ phosphor can emit bright far-red light. All the results indicated that SGWO:Mn4+ phosphors have potential application value in indoor plant cultivation.

The dinuclear complex [Cu2 I2 (L1)2 ] (1) (L1=3-((4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl)methyl)benzonitrile) is characterized by single-crystal X-ray diffraction (XRD), powder XRD, IR, photoluminescence spectroscopy, and thermogravimetric analysis. Unlike other related, known copper iodide complexes, it exhibits strong yellow emission in the solid state at both room temperature and 77 K. Showing good compatibility with PMMA, it is blended with the polymer in different weight ratios to prepare luminescent composite fibers.

The usage of zinc oxide (ZnO)-based nanostructures in photoelectrochemical (PEC) water splitting has been well investigated yet still in keen exploration for further performance enhancement. Multi-walled carbon nanotubes (MWCNTs)-modified ZnO nanorods were prepared via hydrothermal route followed by simple solution deposition. MWCNTs were self-anchored onto the ZnO nanorods and acted as a hole-attracting phase. The PEC performance of MWCNTs-modified ZnO nanorods, including photocurrent density and photo current conversion efficiency (PCE), was found to be significantly improved compared with unmodified ones. The maximum value of PCE (0.646%), which was 2.1 times higher than that of pristine ZnO nanorods, was achieved with a MWCNTs/ethanol suspension concentration of 0.002 wt%. The performance enhancement is attributed to increasing of light absorption from rougher surface and effective charge carrier transport from the excellent conductivity of the incorporated MWCNTs.

We report a highly efficient tunable THz reflector in graphene. By applying a small gate voltage (up to 3 V), the reflectance of graphene is modulated from a minimum of 0.79% to a maximum of 33.4% using graphene/ionic liquid structures at room temperature, and the reflection tuning is uniform within a wide spectral range (0.1 - 1.5 THz). Our observation is explained by the Drude model, which describes the THz wave-induced intraband transition in graphene. This tunable reflectance of graphene may contribute to broadband THz mirrors, deformable THz mirrors, variable THz beam splitters and other optical components., Comment: 4 figures

Recently, the position of shale gas is more and more important in the world energy structure. The lithology of Xiamaling Formation in Beijing area mainly include siltstone, silty shale and shale. The organic carbon content is relatively high, averaging 2.28%. The kerogen type of organic matter is dominated by II1 and II2 types, and thermal evolution level is relatively high, averaging 2.05%. Intergranular micropore is well developed, and most of the micropore diameter is 1-7µm, so the reservoir condition is good. The content of the brittle mineral is relatively high, so it can be easily fractured in production. The content of the clay mineral is relatively high, so it has a good adsorption capacity. Through wild prospecting and geochemical analysis for samples, this paper systematically assesses the Xiamaling Formation shale in Beijing area, which can provide basic stata for further shale gas study in Beijing area.

A target cell extraction-chemical profiling method based on human alveolar adenocarcinoma cell line (A549 cells) and UHPLC/LTQ Orbitrap MS for screening the anti-lung cancer bioactive compounds from Curcuma longa has been developed in this paper. According to the hypothesis that when cells are incubated together with the extract of Curcuma longa, the potential bioactive compounds in the extract should selectively combine with the cells, then the cell-binding compounds could be separated and analyzed by LC-MS. The bioactive compounds in C. longa are lipophilic components. They intend to be absorbed on the inner wall of cell culture flask when they were incubated with A549 cells, which will produce interference in the blank solution. In this paper, by using cells digestion and multi-step centrifugation and transfer strategy, the interference problem has been solved. Finally, using the developed method, three cell-binding compounds were screened out and were identified as bisdemethoxycurcumin, demethoxycurcumin, and curcumin. These compounds are the main bioactive compounds with anti-lung cancer bioactivity in C. longa. The improved method developed in this paper could avoid the false positive results due to the absorption of lipophilic compounds on the inner wall of cell culture flask, which will to be an effective complementary method for current target cell extraction-chemical profiling technology.

Highly porous three-dimensional (3D) hierarchical nanostructures suspended in aqueous media were facilely prepared via electrospinning of polyacrylonitrile (PAN)/indium tin oxide (ITO) nanofibers and collection of the hybrid nanofibers by water, followed by hydrothermally growing ZnO nanorods from the nanofibers. The large inter-fiber distances facilitated the uniform growth of the ZnO nanorods throughout the whole system. The suspended PAN/ITO nanofibers process excellent light trapping capability due to their centimeter-sized dimensions and hence large light penetration path. This significantly increases the probability of multiple-reflections, leading to high absorption with almost zero transmission when the size of the sample reaches 10 mm in the direction parallel to incident light. High photocurrent was generated when the nanorods-on-nanofibers was used as a photoanode. The high photocurrent density generated by the anode can be attributed to its excellent light-trapping capability brought by the large amount of interaction sites between the ZnO nanorods and light, its large contact area with electrolyte, as well as the conduction path constructed by high-content ITO nanoparticles. Accepted version

Solution-processed small-molecule p-DTS(FBTTh2)2:PC71BM bulk heterojunction (BHJ) solar cells with power conversion efficiency of 8.01% are demonstrated. The fill factor (FF) is sensitive to the thickness of a calcium layer between the BHJ layer and the Al cathode; for 20 nm Ca thickness, the FF is 73%, the highest value reported for an organic solar cell. The maximum external quantum efficiency exceeds 80%. After correcting for the total absorption in the cell through normal incidence reflectance measurements, the internal quantum efficiency approaches 100% in the spectral range of 600-650 nm and well over 80% across the entire spectral range from 400 to 700 nm. Analysis of the current-voltage (J-V) characteristics at various light intensities provides information on the different recombination mechanisms in the BHJ solar cells with different thicknesses of the Ca layer. Our analysis reveals that the J-V curves are dominated by first-order recombination from the short-circuit condition to the maximum power point and evolve to bimolecular recombination in the range of voltage from the maximum power point to the open-circuit condition in the optimized device with a Ca thickness of 20 nm. In addition, the normalized photocurrent density curves reveal that the charge collection probability remains high; about 90% of charges are collected even at the maximum power point. The dominance of bimolecular recombination only when approaching open circuit, the lack of Shockley-Read-Hall recombination at open circuit, and the high charge collection probability (97.6% at the short circuit and constant over wide range of applied voltage) lead to the high fill factor.

Uniform and well adhesive nanostructured hydrated tungsten trioxide (3WO 3•H 2O) films were grown on fluorine doped tin oxide (FTO) substrate via a facile and template-free crystal-seed-assisted hydrothermal method by addition of ammonium sulfate ((NH 4) 2SO 4) and hydrogen peroxide (H 2O 2). X-ray diffraction (XRD) studies indicated that the films are of orthorhombic structure. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) analysis showed that the film was composed of brick-like nanostructures with a preferred growing direction along (002). The influence of seed layer, (NH 4) 2SO 4 and H 2O 2 on the products were also studied. The film showed good cyclic stability, comparable switching speed and coloration efficiency (30.1 cm 2 C -1). A complementary electrochromic device based on the film and Prussian blue depicted highly improved color contrast, coloration/bleaching response (1.8 and 3.7 s respectively) and coloration efficiency (164.6 cm 2 C -1).

A hybrid organic–inorganic material based on vermiculite was prepared to remove diethyl phthalate (DEP) from aqueous solution. Natural vermiculite was activated with HCl to improve the specific surface area and was then modified by silanization using trimethylchlorosilane. Organovermiculite prepared by ion exchange with hexadecyl trimethylammonium bromide (HDTMAB) was also tested for comparison. The leaching of 2 mol L −1 HCl at 80 °C increased the specific surface area of vermiculite from 14.4 to 500.0 m 2 g −1 , and the average pore-diameter was decreased from 7.90 nm to 2.75 nm. Fourier transform infrared spectroscopy (FTIR) spectra indicated that trimethysilyl groups were grafted covalently on the surface of acid vermiculites. The specific surface area of trimethylchlorosilane-modified acid vermiculites (TMAVs) (355.4 m 2 g −1 ) was much larger than that of organovermiculite (6.0 m 2 g −1 ). The isotherm adsorption experiments of DEP showed that TMAVs exhibited linear isotherms, suggesting that the uptake of DEP was controlled by partitioning mechanism. The maximal partition coefficient ( K d ) of TMAVs was 3.1 times higher than that of organovermiculite, implying that TMAVs had stronger organic affinity than organovermiculite. The results demonstrate that the adsorption capacity and mechanism of organoclays were controlled by the specific surface area and organic loading, whereas the length of alkyl chain of organic modifier was not the key factor.

We report a fast-switching negative photoelectrochromic cell composed of a dye-sensitized nanocrystalline TiO 2 electrode and Prussian blue counter electrode sandwiching a LiI electrolyte. The cell can be bleached under illumination with shorted TiO 2 and Prussian blue electrodes, and re-colored by applying an appropriate external voltage. The photo-bleaching and electric-coloring processes are fast and reversible. A maximum absorbance modulation of 0.44 recorded at 700 nm is obtained between bleached and colored states for the cell when the PB films thickness is 452 nm. Illuminated under different levels of light intensity or durations of time, the shorted cell shows adjustable optical absorption from 470 to 840 nm. The in-situ transmittance response depicts that the photo-bleaching response is 6.2 s for 70% transmittance change under 100 mW/cm 2 illumination in short circuit configuration, and the re-coloration time is about 600 ms under 2 V bias recorded at 780 nm, with an electrochromic coloration efficiency of 103.4 cm 2/C. The cell shows a good reversible stability and can be potentially applied in erasable displays. © 2011 Elsevier B.V. All rights reserved.

Parathyroid hormone 1 receptor (PTH1R) is a member of the class B G-protein coupled receptor (B-GPCR) family and is involved in bone formation. Its substrate parathyroid hormone (PTH) and its analogues are being developed as anti-osteoporosis therapeutics. The structure-based rational drug design of PTH1R substrates has been hampered by the lack of experimentally determined three-dimensional (3D) structures from techniques such as nuclear magnetic resonance (NMR) and X-ray crystallography. Here, we have constructed a 3D model of PTH1R including its extracellular domain (ECD), transmembrane (TM) domain, and other domains using a homology modeling approach. In addition, to capture the ligand-receptor interactions, we have manually docked human parathyroid hormone (1-34) into the top scoring receptor model, and subjected the PTH-PTH1R complex to an unconstrained energy minimization. The integral 3D receptor model provides an easier way to understand the interactions involved at the TM, ECD, and other domains. Furthermore, the parameters of hydrogen bonding, hydrophobic, and other interactions from the ligand-receptor model, enabled us to elucidate the important interactions between PTH (1-34) and PTH1R. This ligand-receptor model could potentially serve as a tool for structure-based virtual screening in the development of non-peptide based anti-osteoporosis drugs.

An amphiphilic graft copolymer with poly(acrylamide-methacrylate) as a main chain and octylphenyl polyoxyethylene as side chains (P(AM-MA)-g-C8PhEO10) was successfully synthesized via free radical copolymerization. The structure and the composition of the graft copolymer were characterized by FTIR, 1H-NMR and elemental analysis (EA) in detail. The absolute molecular weight of the copolymer is 1.304×106, as determined by static light scattering (SLS). The molar ratio of acrylamide monomer to the macromonomer is 33:1 in the copolymer and 53 C8PhEO10 branch chains attach to a P(AM-MA) backbone. The micellar behavior of P(AM-MA)-g-C8PhEO10 was preliminarily studied by means of surface tension measurements, transmission electron microscope (TEM) in aqueous solution. It was found that the stable spherical micelles with core-shell structure are formed and polymolecular micelles are larger and more compact than monomolecular micelles. In addition, the graft copolymer has favorable thermal stability.

A quasi-solid-state electrolyte employing a poly (ethylene oxide)/LiI system without a filler is evaluated. The electrolyte is optimized for various potassium iodide (KI) concentrations. The electrolyte containing 14.5 wt.% KI exhibits the highest conductivity (3.0 × 10 −3 S cm −1 ). An efficiency of 4.5% is achieved using this composition of the electrolyte. It is shown that the introduction of KI in a conventional PEO/I 2 /LiI electrolyte system prevents the crystallization of the polymer matrix and enhances the ionic conductivity. The energy conversion efficiency of the device is further enhanced to 5.8% by incorporating a light-scattering layer.

The dependence of morphology and polymer-chain orientation of regioregular poly(3-hexylthiophene) (rrP3HT) thin films on processing conditions have been widely studied. However, their possible variation across the film thickness direction remains largely unknown. We report here a marked difference in the optical dielectric (n,k) spectra between the top and bottom interfaces of spin-cast (sc) rrP3HT films deposited from chlorobenzene solutions. These spectra were obtained from reflection variable-angle spectroscopic ellipsometry using a self-consistent graded optical model with self-imposed Kramers-Krönig consistency. The top interface shows a red-shifted absorption that is characteristic of better order than at the bottom, across a wide range of film thicknesses. This disparity diminishes in drop-cast (dc) and multipass inkjet-printed (ijp) films, and disappears in amorphous films such as those of polystyrene and of a green-emitting phenyl-substituted poly(p-phenylenevinylene). The (n,k) spectra also reveal that crystallinity increases across scdcijp films. This is supported by cross section scanning electron microscopy of the cleaved edges and measurement of the microroughness of both the film interfaces. Furthermore, optical anisotropy decreases across scdcijp films. Finally, near-edge X-ray absorption fine structure spectroscopy also shows the frontier chains in ijp and dc films are more isotropically oriented than those in sc films. These results suggest that semicrystalline conjugated polymer films can be produced far from equilibrium. This explains the marked variation in their (opto)electronic properties between the top and bottom surfaces that has sometimes been found depending on the film deposition method. In particular, an unusually pronounced crystallization is induced by ijp. We label this marked ijp-induced crystallization the "ijp morphology", which appears to be general, as it is found also in single-inkjet-droplet films. It appears also to be responsible for the lower field-effect mobility measured for ijp films deposited on a variety of linear and circular electrode arrays. This however can fortuitously be reversed by annealing in solvent vapor. As all films were deposited in the low Peclet-number regime, we can rule out surface skin formation. We attribute the extensive crystallization to the non-uniform drying of picoliter droplets, further promoted by repeated film swelling-deswelling cycles in multipass-ijp films.

The degradation process in pentacene-based organic thin-film transistors (OTFTs) is investigated. Pentacene-based OTFTs were fabricated with and without octadecyl trichlorosilane (OTS) treatment, and their device characteristics during lifetime test are evaluated using low-frequency-noise (LFN) spectroscopy. It is found that the devices exhibited the 1/f type of noise behavior with generation and recombination noise superimposed. The drain-current noise was found to vary proportionally with drain current according to Hooge's empirical relation of flicker noise. Devices without any treatment show obvious interface traps and deep-level traps, while devices with OTS treatment show nonexistence of interface traps and suppression of deep-level traps. The LFN intensity is found to decrease during the device lifetime test initially, while upon the device failure, the noise level is observed to increase again. The viability of using LFN as a diagnostic tool in the organic transistor is demonstrated.

Zinc oxide (ZnO)-based dye-sensitized solar cell was fabricated and tested under constant solar simulator illumination until the photocurrent decreased. Electrolyte and dye were studied by Fourier transform infrared and UV–vis absorption spectroscopy. Scanning electron microscopy, photoluminescence and X-ray photoelectron spectroscopy were used to study the degradation of ZnO. Secondary Ion Mass spectroscopy was used to analyze the structural change of the device during the degradation process. The degradation process of dye-sensitized solar cell is started when N3 dye slowly gets desorbed from the ZnO surface and gets incorporated into the electrolyte. Electron injection decreases with time as more dye gets desorbed. The degradation process is further accelerated when ions of Zn, O and In are diffused into the electrolyte as this process create defect vacancies on the ZnO nanorod surface. The stability of the semiconductor surface and interface between the semiconductor and dye are crucial to improve device lifetime.

We fabricated three optically compensated bend (OCB) polymer-dispersed nematic liquid crystal (PDLC) cells doped with a minute amount of multiwalled carbon nanotubes (MWCNTs) and observed the eletrohydrodynamic (EHD) behaviors of LCs in these three MWCNT-doped OCB PDLC cells at 5 or 12 V AC voltage with a frequency of 1 kHz or 60 Hz, respectively. Using the polarizing microscope, we discovered many kinds of domain patterns, including the fingerprint-like domain pattern, the uniform domain pattern, the bean-like domain pattern, the irregular big spot domain pattern, the hexagonal short period lattice domain pattern, and the rectangular period lattice domain pattern. This suggests that some domain patterns differ from the Kapustin–William's domain pattern while others were somewhat similar to the Kapustin–William's domain pattern.

2,7-dibromo-N-hexylcarbazole is successfully synthesized in three steps with an overall 37% yield. Novel 2,7-carbazole-based sterically hindered conjugated polymers are further synthesized. In the backbone structure of polymer P1, alkylated bithiophene moiety is β-substituted with dodecyl chains on both thiophene rings, adopting the tail-to-tail configuration. While for polymers P2 and P3, partially planarized thieno[3,2-b]thiophene moiety (P2) and β-pentyl substituted thieno[3,2-b]thiophene (P3) are incorporated. All polymers demonstrate efficient blue-to-green light emission, good thermal stability (Td ≥ 379 °C), and high glass transition temperatures (Tg = 118 °C). The optical and electronic properties of the resulted polymers are tuned by the incorporated alkyl chains. For instance, the incorporation of β-pentyl group in thieno[3,2-b]thiophene moiety endows P3 with blue-shifted photophysical spectra, reduced fluorescence quantum yield and larger band gap in comparison with P2. The steric effect of incorporated alkyl chains is further illustrated by geometry optimization of three model oligomers (analogues to the repetition units of P1–P3) using density functional theory. Sterically hindered polymers P1 and P2 exhibit high charge transport ability and moderate electroluminescent properties in primarily tested single-layer light-emitting diodes (configuration: ITO/PEDOT:PSS/Polymer/Ca/Ag). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7725–7738, 2008

A semi-artificial thermocouple device is developed to explore the dynamic cutting temperature variation rules in high-speed milling of Al7050-T7451 aluminum alloy. Both the aluminum-constantan thermocouple calibration diagram and cutting temperature curves are obtained. The cutting temperature empirical formula is constructed by means of orthogonal experimental design and multivariate linear regression analyses. It shows a reasonable good match between the theoretical predicted values and the measured temperatures. This allows for the optimization of cutting parameters and the exploration of machining deformation induced by the cutting heat in high-speed milling of aerospace aluminum monolithic constructions.

A one-dimensional linear chain polymer {[Mn(OOCC6H4Fc)2(μ 2-OH2)(DMF)2]} n (1) was obtained by substitution from a precursor polymer {[Mn(OOCC6H4Fc)2(μ 2-OH2)(H2O)2](H2O)} n (P1), in which the terminal coordinated H2O molecules are substituted by DMF, while the bridging aqua molecules are intact, so product 1 and precursor P1 are isomorphous. Polymer 1 behaves as a 1D Heisenberg Mn(II) chain with weak intrachain antiferromagnetic interaction between the local high-spin Mn(II) ions; the exchange coupling parameters J = −5.00 cm−1 are larger than most of the reported di-Mn(II) complexes containing μ 2-aqua and μ 2-carboxylato units and some one-dimensional Mn(II) carboxylic polymers.

The optical and electrical properties of a novel alcohol soluble aminoalkyl-substituted cationic conjugated polymer, poly[9,9′-bis(6″-(N,N,N-trimethylammonium)-hexyl)fluorene-co-alt-2,5-dimethoxy-1,4-phenylene dibromide] (PFPB), has been studied using absorption, photoluminescence, current–voltage–luminescence (J–V–L), and noise characterization techniques. The absorption and photoluminescence studies show that PFPB is blue-emitting, and its long alkyl side chains and two methoxy side chains introduce steric hindrance in the structure, which can minimize interchain interactions. The photoluminescence quantum efficiency of PFPB in methanol was found to be 69.6%. Polymer light emitting diodes (PLEDs) were fabricated using PFPB as an electron injection layer and device physics has been studied. The obtained device results indicate that PFPB can be used as an electron transport layer (ETL) to improve the PLED performance. The noise characteristics on the PLED devices show that the interface between the cathode and the emissive layer is improved through the introduction of a PFPB layer. Results in this report indicate that the poly(fluorene-co-phenylene)-based water/alcohol soluble cationic conjugated polymer avoids the intermixing between the electroluminance layer and adjacent ETL layer which is a common and serious problem in multilayer PLED fabrication by solution casting methods. This makes water solubility materials attractive for applications in PLEDs and other organic devices.

The luminance–time behavior of organic light emitting device (OLED) was measured using a photodiode and the low frequency noise–time spectrum from photodiode current is also measured and investigated. Square pulses noises were observed in time domain and the laws of their occurrences were obtained and studied. The square pulses are believed to be related to sudden change in carrier numbers in the device as part of degradation process. It shows that two dominant mechanisms take turn to generate the optical noise levels. The degradation process is postulated to describe the corresponding noise change. This optical noise observation is a direct reflection of polymer intrinsic degradation.

Sources of carbonaceous aerosols collected from three sites of Chattanooga, TN (CH), Muscle Shoals, AL (MS), and Look Rock, TN (LR) in the Tennessee Valley Region (TVR) were apportioned using both organic tracer-based chemical mass balance (CMB) modeling and radiocarbon (14C) measurement and the results were compared. Eight sources were resolved by CMB, among which wood combustion (averaging 0.92 μg m−3) was the largest contributor to primary organic carbon (OC) concentrations, followed by gasoline exhaust (0.35 μg m−3), and diesel exhaust (0.18 μg m−3). The identified primary sources accounted for 43%, 71%, and 14% of measured OC at CH, MS, and LR, respectively. Contributions from the eight primary sources resolved by CMB could explain 107±10% of ambient elemental carbon (EC) concentrations, with diesel exhaust (66±32%) and wood combustion (37±33%) as the most important contributors. The fossil fractions in total carbon determined by 14C measurements were in reasonably good agreement with that in primary (OC+EC) carbon apportioned by CMB in the MS winter samples. The comparison between the 14C and CMB results revealed that contemporary sources dominated other OC in the TVR, especially in summertime (84% contemporary).

The polyfluorene/poly(p-phenylenevinylene) copolymer based hole-only devices are fabricated and the current–voltage characteristics are measured as a function of temperature. The hole current is fitted well with space-charge limited and field-dependent mobility model, which provides a direct measurement of the hole mobility μ as a function of electric field E and temperature. The mobility is fitted with existing Gill’s model, Gaussian disorder model, correlated Gaussian disorder model and Brownian motion model. Energy hopping time and activation energy are obtained from Brownian motion model. Microscopic transport parameters are derived and a consistent picture of the influence of the molecular structure of the polymer on the charge transport is depicted. For the polyfluorene/poly(p-phenylenevinylene) copolymer, although with a high degree of irregularity in structure and larger energetic disorder, the two bulky structure favors charge delocalization and remove defect sites, results in a higher mobility. The results suggest space-charge limited and field-dependent mobility model combine with various mobility model, include Brownian motion model, is a useful technique to study charge transport in thin films with thicknesses close to those used in real devices.

Alternating conjugated copolymers comprised of 9,9-dihexylfluorene and unsubstituted/substituted thieno[3,2-b]thiophene moieties were synthesized using the Suzuki coupling reaction. The structures of these polymers were characterized, and their thermal, photophysical, electrochemical, and electroluminescent properties were investigated. By β-substitution of thieno[3,2-b]thiophene moiety with alkyl chain, the thermal, electrochemical, and electroluminescence properties of the resulted polymers were tuned. The polymers exhibited good thermal stability with decomposition temperature (Td) in the region of 308−431 °C and their glass transition temperatures (Tg) ranging from 126 to 146 °C. Incorporation of β-alkyl chain onto thieno[3,2-b]thiophene of the alternating copolymers led to lowered Tdand Tg and blue-shifted maximum wavelengths in both absorption and emission spectra. The influence of β-alkyl substitution on the conformation of the polymer chains was evaluated by simulating the optimized geometries of ...

Various thicknesses of magnesium fluoride (MgF 2 ) ultrathin films were inserted between electroluminescence layer and cathode in poly( p -phenylene vinylene) (PPV)-based organic light-emitting devices. It is observed that device with 0.4 nm of MgF 2 has the highest luminance and current efficiency. At 7 V operation, the current efficiency has improved by approximately 1.5 times as compared to the standard device. The increase in device current and the improvement in efficiency are due to increased electron injection, leading to more balanced hole and electron numbers. At the same time, device with a layer of MgF 2 inserted between anode indium tin oxide and polyethylenedioxythiophene has also shown obvious improvement in performance. It is observed that the device with 0.4 nm of MgF 2 in anode side has the highest luminance and current efficiency. The improvement of the device performance in anode side are due to smoothened interface which boosts hole injection and the fluoride ions doping the PPV materials resulting in an increase of its electron affinity which mitigates the electron and hole's number imparity.

Drilling carbon fiber reinforced plastics and titanium (CFRP/Ti) stacks is one of the most important activities in aircraft assembly. It is favorable to use different drilling parameters for each layer due to their dissimilar machining properties. However, large aircraft parts with changing profiles lead to variation of thickness along the profiles, which makes it challenging to adapt the cutting parameters for different materials being drilled. This paper proposes a force sensorless method based on cutting force observer for monitoring the thrust force and identifying the drilling material during the drilling process. The cutting force observer, which is the combination of an adaptive disturbance observer and friction force model, is used to estimate the thrust force. An in-process algorithm is developed to monitor the variation of the thrust force for detecting the stack interface between the CFRP and titanium materials. Robotic orbital drilling experiments have been conducted on CFRP/Ti stacks. The estimate error of the cutting force observer was less than 13%, and the stack interface was detected in 0.25 s (or 0.05 mm) before or after the tool transited it. The results show that the proposed method can successfully detect the CFRP/Ti stack interface for the cutting parameters adaptation.

Background Exposure to air pollution and, more specifically, particulate matter (PM) is associated with adverse health effects. However, the specific PM characteristics responsible for biological effects have not been defined. Objectives In this project we examined the composition, sources, and relative toxicity of samples of PM with aerodynamic diameter ≥2.5 μm (PM2.5) collected from sites within the Southeastern Aerosol Research and Characterization (SEARCH) air monitoring network during two seasons. These sites represent four areas with differing sources of PM2.5, including local urban versus regional sources, urban areas with different contributions of transportation and industrial sources, and a site influenced by Gulf of Mexico weather patterns. Methods We collected samples from each site during the winter and summer of 2004 for toxicity testing and for chemical analysis and chemical mass balance–based source apportionment. We also collected PM2.5 downwind of a series of prescribed forest burns. We assessed the toxicity of the samples by instillation into rat lungs and assessed general toxicity, acute cytotoxicity, and inflammation. Statistical dose–response modeling techniques were used to rank the relative toxicity and compare the seasonal differences at each site. Projection-to-latent-surfaces (PLS) techniques examined the relationships among sources, chemical composition, and toxicologic end points. Results and conclusions Urban sites with high contributions from vehicles and industry were most toxic.

Recent developments in the field of microbiology and research on the origin of life have suggested a possible significant role for reduced, inorganic forms of phosphorus (P) such as phosphite [HPO(3)(2-), P(+III)] and hypophosphite [H(2)PO(2)(-), P(+I)] in the biogeochemical cycling of P. New, robust methods are required for the detection of reduced P compounds in order to confirm the importance of these species in the overall cycling of P in the environment. To this end, we have developed new batch and flow injection (FI) methods for the determination of P(+III) in aqueous solutions. The batch method is based on the reaction of P(+III) with a mixed-iodide solution containing tri-iodide (I(3)(-)) and penta-iodide (I(5)(-)). The oxidation of P(+III) consumes free I(3)(-) and I(5)(-) in solution. The remaining I(3)(-) and I(5)(-) subunits are then allowed to react with the amylose content in starch to form a blue complex, which has a lambda(max) of 580 nm. The measurement of this blue complex is directly correlated with the concentration of P(+III). The on-line FI method employs the same reaction between P(+III) and mixed-iodide producing phosphate [P(+V)] that is determined spectrophotometrically by the molybdenum blue method employing ascorbic acid at a lambda(max) of 710 nm. The linear range for both the batch and FI determination of P(+III) was 1.0-50 microM with detection limits of 0.70 and 0.36 microM, respectively. Interference studies for the batch method show that arsenite [As(+III)] and sulfite [S(+IV)] can also be determined by this technique; however, these interferences can be circumvented by oxidizing As(+III) and S(+IV) using KMnO(4) which is an ineffective oxidant for P(+III). Both methods were applied to P(+III) determinations in ultra-pure water and simulated creek water. Results and analytical figures of merit are reported and future work is considered.

A series of novel well-defined polyfluorene-based rod−coil copolymers have been synthesized for application in light-emitting diodes (LEDs). These polymers were prepared by using polyfluorene macroinitiators to initiate the atom transfer radical polymerization of 2-(9-carbazolyl)ethyl methacrylate (CzEMA). The incorporation of CzEMA block successfully created energy transfer, and the findings showed that intramolecular energy transfer dominates in solution while intermolecular energy transfer plays a more important role in solid state. It was also demonstrated that energy transfer is more efficient for the block copolymers with respect to the corresponding polymer blends. Better spectral stability has been demonstrated with these copolymers in comparison to PF homopolymer through annealing studies. Interesting self-assembled nanostructures were observed for these polymers, which is dependent on the polymer composition. Electrochemical characterization indicated that the presence of the carbazole effective...

The zero-dimensional polymer [Pb 6 (μ 2 OOCCH=CHFc) 2 -(μ 3 -OOCCH=CHFc) 2 (μ 2 -η 2 -OOCCH=CHFc) 2 (η 2 -OOCCH= CHFc) 2 (μ 4 -O) 2 ] (1), the one-dimensional chain polymers [Pb(η 1 -μ 2 -OOCCH=CHFc) 2 (Phen)] n (phen = phenanthroline; (2), j[Cd(μ 2 -η 2 -OOCCH=GHFc)(η 2 -OOCCH=CHFc)(H 2 O) 2 ]-(H 2 O) 4 ] n (3), and the two-dimensional hybrid polymer {[Cd-(η 2 -OOCCH=CHFC)(bbbm) 1 . 5 Cl].1.5H 2 O} n [bbbm = 1,1'-(1,4-butanediyl)bis-1H-benzimidazole; 4] have been prepared by the reaction of sodium β-ferrocenylacrylate [FcCH= CHCOONa, Fc = (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )] with the appropriate metal salts. Solution-state differential pulse voltammetry for 1-4 indicated that the half-wave potentials of the ferrocenyl moieties in these polymers are all shifted to positive potential compared with that of sodium β-ferrocenylacrylate. The four polymers' third-order nonlinear optical (NLO) properties were determined by the Z-scan technique in DMF solutions. The results show that these polymers possess good nonlinear optical refraction effects. Their hyperpolarizability (y) values are calculated to be 4.80 × 10 - 3 0 , 5.19 × 10 - 3 0 , 1.57 × 10 - 2 9 , and 2.04 × 10 - 2 9 esu for 1-4, respectively. The γ values of the Cd I I polymers (3 and 4) are slightly larger than those of the Pb I I polymers (1 and 2), which indicates that the metal ions play an important role in the NLO properties of these polymers.

Copper-doped zinc oxide nanowires were fabricated on copper-coated silicon substrate by sintering a mixture of zinc oxide and graphite powders at high temperature. Copper functioned as a catalyst in the zinc oxide nanowire growth and was incorporated during the growth as a dopant. The size of copper-doped zinc oxide nanowires ranges from 30 to 100 nm in diameter and tens to hundreds of microns in length. The photoluminescent excitation spectra showed multiple absorption peaks in the ultraviolet and blue/green region. Correspondingly, broad and continuous photoluminescence spectra were observed extending from the ultraviolet to the red region with shoulder peaks at room temperature, which is different from that of the bulk. The x-ray photoelectron spectroscopy and low temperature photoluminescence were employed to analyse the luminescent mechanism.

An organic light-emitting device structure with a thin parylene layer deposited by low-temperature chemical vapour deposition at the anode-organic interface was fabricated. Such a structure gives higher luminescence efficiency when operated at the same current density compared to one without the parylene layer. In addition, the devices with a thin parylene layer also show a smaller number and smaller size dark non-emissive areas, slower growth rate of the dark areas and a longer device lifetime. The modified surface of the indium tin oxide (ITO) shows an increased work function compared to that of the ITO surface alone and a reduced surface roughness, which contributes to the device performance improvement. The parylene layer is a conformal coating on the ITO surface, which could significantly stabilise the interface leading to a more uniform current density. It also provides a good barrier for blocking oxygen and moisture diffusion and hence reducing dark spot occurrence.

An organic light emitting device (OLED) structure with a thin parylene layer deposited by low-temperature chemical vapour deposition (CVD) at the anode–organic interface was fabricated. Such a structure gives off higher efficiency, a smaller number and smaller size dark non-emissive areas, slower growth rate of the dark areas and a longer device lifetime compared to one without the parylene layer. The parylene modified indium tin oxide (ITO) surface shows an increased work-function and a reduced surface roughness compared to that of the bare ITO surface. The interface optimisation contributes to the device performance improvement.