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In this work, thin-film lithium niobate (LiNbO 3 ) acoustic delay line (ADL) based oscillators are experimentally investigated for the first time for the application of single-mode oscillators and frequency comb generation. The design space for the ADL-based oscillator is first analyzed, illustrating that the key to low phase noise lies in high center frequency ( $f_{o}$ ), large delay ( $\tau_{G}$ ), and low insertion loss (IL) of the delay. Therefore, two self-sustained oscillators employing low noise amplifiers (LNA) and a low IL, long delay ( $f_{o}=157\ \mathrm{MHz},\ \mathrm{IL} =2.9\ \mathrm{dB},\ \tau_{G}= 200-440\mathrm{ns}$ ) SH 0 mode ADLs are designed for a case study. The two SH 0 ADL oscillators show measured phase noise of −109 dBc/Hz and −127 dBc/Hz at 10-kHz offset while consuming 16 mA and 48 mA supply currents, respectively. Although the carrier power of the proposed oscillator is lower than published state-of-the-art ADL oscillators, competitive phase noise performance is still attained thanks to the low IL. Finally, frequency comb generation is also demonstrated with the same delay line and a commercial RF feedback amplifier, showing a comb spacing of 3.4 MHz that matches the open-loop characterization.

To examine the association between serum uric acid (UA) levels and cardiovascular risk factors in subjects without diabetes or hyperuricemia.6172 women and 2662 men aged 50+ years without diabetes from Phase 1 of the Guangzhou Biobank Cohort Study were included. Data on personal history, physical examination and biochemical parameters were collected. Subjects were categorized by serum UA concentration, and the association between UA levels and cardiovascular risk factors was examined using generalized linear models.In both men and women with normouricemia (UA420 μmol/l in men and360 μmol/l in women), tertiles of UA levels were adversely associated with body mass index, waist circumference, waist-to-hip ratio, total- and HDL-cholesterol, apolipoprotein A1, systolic and diastolic blood pressures, pulse pressure, fasting plasma glucose and white blood cell count (P value for trend ranged from 0.04 to0.001), and also consistently associated with metabolic disorders including obesity, hypertension, hypertension treatment, dyslipidemia, waist circumference increased since the age of 18 years and the metabolic syndrome (P value for trend ranged from 0.02 to0.001).Increasing UA levels, even in subjects with normouricemia and without diabetes, were associated with increasing prevalence of cardiovascular risk factors, suggesting that clinically dichotomous definition of hyperuricemia may be inadequate and high-normal value of UA may warn of metabolic disorders.

Tumor necrosis factor superfamily 15 (TNFSF15) is an endogenous neovascularization inhibitor and an important negative regulator of vascular homeostasis. This study aimed to explore the potential role of TNFSF15 in diabetic retinopathy. Vitreous TNFSF15 and VEGF levels in proliferative diabetic retinopathy (PDR) patients were detected by ELISA. Retinal expression of TNFSF15 and the content of tight junction proteins (TJPs) in rats were detected by immunohistochemistry and Western blot, respectively. The blood retinal barrier (BRB) permeability was evaluated using Evans Blue (EB) dye. The TNFSF15/VEGF ratio was decreased in the vitreous fluid of patients with PDR relative to the controls, even though the expression levels of TNFSF15 were higher. TNFSF15 was dramatically decreased one month later after diabetes induction (p < 0.001), and then increased three months later and thereafter. TNFSF15 treatment significantly protected the BRB in the diabetic animals. Diabetes decreased TJPs levels in the retina, and these changes were inhibited by TNFSF15 treatment. Moreover, TNFSF15 decreased activation of VEGF both in mRNA and protein levels caused by diabetes. These results indicate that TNFSF15 is an important inhibitor in the progression of DR and suggest that the regulation of TNFSF15 shows promise for the development of diabetic retinopathy treatment strategies.

Effect of copper compounds on the catalytic activity of n-Bu2SnO in the transesterification of dimethyl carbonate and phenol to diphenyl carbonate was investigated. The results showed that they as promoters could obviously enhance the activity of n-Bu2SnO except for Cu. The characterizations of X-ray diffraction (XRD) identified that CuO could be reduced to Cu, and Cu2O was stable. When the reaction was carried out between 150 and 180 oC, with molar ratio of n-Bu2SnO to Cu2O of 8:1, catalyst amount 0.0067, reaction time 10h, molar ratio of dimethyl carbonate to phenol of 3:1, the phenol conversion and the transesterification selectivity were 60.3% and 99.2%, respectively. In the transesterification, the acid-base synergistic effect between Cu2O as the basic promoter and n-Bu2SnO as the Lewis acid resulted in the active enhancement of n-Bu2SnO. Moreover the performance of Cu2O remained unchanged for seven times reuse.

An approach for the synthesis of Ag/Pt nanoparticle-incorporated polyaniline (PANI) nanofibers and Ag/Pt nanoparticles was developed that considers both thermodynamic and kinetic aspects. Ag/Pt nanoparticles and PANI nanofibers are generated simultaneously by the reduction of Ag + /Pt 4+ ions to Ag/Pt nanoparticles and by the polymerization of aniline (ANI) to PANI nanofibers. The PANI nanofibers serve as anchor seeds for the formation of Ag/Pt nanoparticles. The simple and inexpensive route for the preparation of PANI-Ag/Pt nanocomposites can be extended to the polymerization of ANI derivatives and the formation of metal/metal oxides for applications such as sensors, direct methanol fuel cells, and capacitors.

Aim To study the protein expression of kidney tissues changes in the IgA nephropathy (IgAN) mice induced by dextran and effects of Aqueous-extracted Astragali Radix (AEAR) on IgAN mice. Methods IgAN model was established by administrating dextran to normal mice. Some of the dextran-treated mice were given AEAR 10 g·kg −1 per day as the AEAR group. To gain insights into the pathomechanism of the protective effect, two-dimensional electrophoresis (2-DE) of protein patterns of the kidney tissues samples was carried out for normal control group, untreated (IgAN model) group, and AEAR treated group, respectively. After stained by silver staining method, the images were analyzed by PDQUEST 2-D-image analysis software. Results In a 12-week pharmacological study, oral administration of AEAR to IgAN mice induced by dextran not only reduced the levels of blood urea nitrogen (BUN), creatinine (Cr) and urine protein, but also made the differential protein patterns of kidney tissue of IgAN mice observably recover. Compared with the normal control group, about 334 kidney proteins were found significantly changed in the untreated group, in which 142 proteins increased 2 folds, 61 proteins increased 5 folds and 121 protein spots decreased more than 2 folds, and 10 proteins were uniquely expressed in untreated group. Compared with the untreated group, significantly changes in AEAR treated group were found. 50% of above 334 different proteins were regulated to near normal one in AEAR treated group. In the above 10 unique proteins, 5 spots fully recovered to the un-expression state of normal control group, 4 spots observably decreased and neared the normal expression level, and 1 protein slightly increased in AEAR treated group compared with the untreated group. Conclusions AEAR was found to induce protective effect on renal function in IgAN mice and could play an important role in regulating these protein alterations, which would help us to find the target protein markers related to AEAR effects on IgAN in mice.

The film of polyaniline nanowires (PANI (NW)) was deposited onto the surface of stainless steel electrode through galvanostatic polymerization of aniline (ANI) and utilized for the fabrication of Pt particles loaded catalyst electrode. PANI (NW) was doped with poly (styrene sulfonic acid) (PSS) by a sequential doping–dedoping–redoping process, to result a PANI (NW)-PSS spatial matrix. UV–vis spectroscopy confirms the success of doping–dedoping–redoping process to obtain PANI (NW)-PSS. Pt particles were deposited into the film of PANI (NW) and PANI (NW)-PSS by using potentiostatic mode (−0.2 V vs. Ag/AgCl). The morphology and structure of different PANI films were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). XPS results demonstrated that PANI (NW)-PSS has more positively charged nitrogens and minimum content of side products than simple PANI (NW). AES results revealed that Pt particles were distributed into the spatial regions of PANI (NW)-PSS. Cyclic voltammetry (CV) and chronoamperometry measurements were used to investigate the electrochemical properties, electrocatalytic activity and stability of PANI (NW)/Pt and PANI (NW)-PSS/Pt electrode towards oxidation of methanol. PANI (NW)-PSS/Pt electrode with a spatial distribution of Pt particles showed an improved catalytic performance towards oxidation of methanol than the PANI (NW)/Pt electrode.

Platinum–Ruthenium (Pt–Ru) nanoparticles were generated along with the simultaneous formation of poly(2,5-dimethoxyaniline) (PDMA) in the presence of poly(styrene sulfonic acid) (PSS) using a one-step UV-assisted method. The existence of Pt–Ru nanoparticles was verified through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The latter two confirmed that the surface state of Ru in the Pt–Ru nanoparticles not only has metallic characteristics but is also present in oxidized form. The existence of PDMA in PSS was also identified using ultraviolet–visible (UV–vis) spectroscopy. Based on electrochemical measurements, PDMA–PSS–Pt–Ru exhibited a much higher electrocatalytic activity than PDMA–PSS–Pt and bulk Pt in methanol oxidation. Under the appropriate conditions, these particles can potentially serve as robust electrocatalysts in fuel cell applications.

Polyaniline–poly(styrene sulfonic acid)–platinum (PANI–PSS–Pt) composite is prepared through an interfacial polymerization route. The composite is obtained by incorporating Pt nanoparticles into conductive PANI matrix by the reduction of Pt4+ ions to Pt nanoparticles during the oxidative polymerization of aniline in PSS as medium. The interfacial synthesis offers the microenvironment for the growth of PANI nanostructures with simultaneous incorporation of Pt nanoparticles to result PANI–PSS–Pt nanocomposite. PANI–PSS–Pt nanocomposite is characterized by UV–Vis absorption spectroscopy, FTIR spectroscopy, scanning microelectronic microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).

Nanocomposites comprised of Pt nanoparticles and electrically conducting polymers were prepared and tested for the electrocatalytic performance towards oxidation of methanol. Films of polyaniline (PANI) synthesized independently by potentiostatic and galvanostatic method, PANI(V) and PANI(I), respectively, were used as the supporting matrix for loading Pt nanoparticles. PANI(V), PANI(I), PANI(V)/Pt, and PANI(I)/Pt films were characterized for structure and morphology using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). SEM image of PANI(I) reveals that the particles are highly porous and interconnected nanowires, whilst PANI(V) particles are granular. The large surface area in the nanofibrillar PANI(I) makes the dispersion of Pt particle with a lesser time for the deposition of Pt particles. The porous network structure of PANI(I) helps in effective dispersion of Pt particles (about 10–20 nm) and facilitates easy access of methanol to the catalytic sites. The electrocatalytic activity of PANI(I)/Pt is much higher (current density (24.7 mA/cm 2 mg) at 0.68 V) in comparison to PANI(V)/Pt and bulk Pt electrodes (the current density values of 5.5 and 7.5 mA/cm 2 mg).

Simultaneous synthesis of conductive poly(2,5-dimethoxyaniline) (PDMA) and silver nanoparticles can be achieved in the presence of poly(styrene sulfonic acid) (PSS). The reaction is conducted by choice of the concentrations of PSS, AgNO3 and DMA. In situ UV–vis spectroscopy has been used to monitor the formation of PDMA. Both in situ UV–vis and FTIR results reveal that the rate of polymer formation, electronic state and oxidation state of PDMA–PSS–Ag are strongly dependent on the concentration of PSS in the present system. Transmission electron microscopy shows that silver nanoparticles size is reduced with increasing the concentrations of PSS and DMA.

Polyaniline (PANI) can be doped with poly(styrene sulfonic acid) (PSS) via doping–dedoping–redoping process. The specific characteristics of PANI doped with PSS (PANI-PSS) were checked by UV–vis spectroscopy, cyclic voltammetry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). PANI-PSS was found to have spatial structure with minimum degradation products. Platinum can be potentiostatically deposited in a spatial layer of the PANI-PSS as evidenced by electron dispersive element analysis (EDS) and Auger electron spectroscopy (AES). The electrochemical measurements demonstrated that PANI-PSS-Pt exhibited a much higher electrocatalytic activity for methanol oxidation than PANI-Pt.

Polyaniline (PANI) with nanowire (PANI-(NW)) network structure (mean diameter 10–20 nm) was successfully deposited on a stainless steel (SS) electrode by a galvanostatic process. Platinum particles were deposited into the PANI nanowire network structure to result the PANI(NW)-Pt composite electrode. The PANI(NW)-Pt electrode was used as electrocatalysts for the electrochemical oxidation of methanol. The PANI nanowires and PANI(NW)-Pt nanocomposite were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV–vis absorption spectroscopy. Nanowire morphology with an average diameter of 10–20 nm could be seen from scanning electron micrograph. Small amount (70 mμm) of spherical Pt particles could be deposited into the PANI(NW). Catalytic activity for the oxidation of methanol was studied by using cyclic voltammetry (CV). For comparative purposes, bulk Pt (deposited Pt on SS) and PANI nanowires based electrodes were tested. The PANI(NW)-Pt nanocomposite electrode exhibited excellent catalytic activity for the electrooxidation of methanol in comparison to bulk Pt electrodes, which reveals that the PANI(NW)-Pt nanocomposite electrodeis more promising for application in electrocatalyst as a support material. POLYM. COMPOS., 28:650–656, 2007. © 2007 Society of Plastics Engineers

Hydrous RuO 2 particles were electrochemically loaded into poly(3,4-ethylenedioxythiophene) doped poly(styrene sulfonic acid), PEDOT-PSS, matrix by employing various potential cycles in cyclic voltammetry and to fabricate the PEDOT-PSS-RuO 2 · x H 2 O electrode. The amount of hydrous RuO 2 particles loaded into the PEDOT-PSS matrix was easily controlled by varying the number of potential cycles. Scanning electron microscopy photographs reveal a uniform dispersion of hydrous RuO 2 particles in the porous structure of PEDOT-PSS matrix. Raman spectrum confirms the incorporation of hydrous RuO 2 into PEDOT-PSS matrix. Chronopotentiometry and cyclic voltammetry were employed in 0.5 M H 2 SO 4 to evaluate the capacitor properties. Specific capacitance values were determined by chronoamperometry. An increasing trend in specific capacitance with loaded amount of hydrous RuO 2 particles in PEDOT-PSS was noticed. A maximum specific capacitance of 653 F/g was achieved.

A new catalyst electrode was prepared in which Pt particles were homogeneously distributed into a poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonic acid) (PEDOT–PSS) matrix. Catalytic activity and stability for the oxidation of methanol were studied by using cyclic voltammetry and chronoamperometry. For comparative purposes, bulk Pt and PEDOT–PSS based electrodes were fabricated and tested. Enhanced electrocatalytic activity toward the oxidation of methanol was noticed when Pt particles were embedded into the PEDOT–PSS matrix. A high catalytic current for methanol oxidation (2.51 mA cm −2 ) was found for the PEDOT–PSS–Pt electrode in comparison to bulk Pt electrode (0.45 mA cm −2 ) at +0.6 V (versus Ag/AgCl). The enhanced electrocatalytic activity might be due to the dispersion of Pt particles into the PEDOT–PSS matrix and the synergistic effects between the dispersed Pt particles and the PEDOT–PSS matrix. The morphology and crystalline behavior of PEDOT–PSS–Pt and simple ITO/Pt films were determined by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) and correlated with the enhanced electrocatalytic activity for the Pt-dispersed PEDOT–PSS electrode.

A flexible electrochromic device is reported by using polyaniline (PANI) doped with dl -camphor-10-sulfonic acid (CSA)/poly(styrene sulfonic acid) (PSS) as coloring electrodes and poly(ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) as complementary electrodes. The characterizations of the devices were performed by using cyclic voltammetric and in situ UV–vis spectroelectrochemical studies. The devices demonstrates the color change from pale yellow (−0.5 V) to dark blue (+2.5 V). The improvement of optical properties, such as coloration efficiency and stability on the basis of PANI doped with PSS and PEDOT-PSS. Furthermore, the optical properties keep the same as the device is situated at the bending state.

A new composite film was prepared by depositing hydrous ruthenium oxide (RuO 2 ) particles into a polymer matrix comprising of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(styrene sulfonic acid) (PSS). The composite, PEDOT–PSS–RuO 2 , showed an enhanced capacitance and optical properties due to the presence of RuO 2 particles in the composite. Specific capacitance of the PEDOT–PSS–RuO 2 composite was found to be 1409 F/g. After anodic polarization, the PEDOT–PSS–RuO 2 composite film exhibited enhanced visible-light coloration in comparison with PEDOT/PSS and simple RuO 2 films. Differential voltabsorptometric curves (d A /d t versus potential (derivative cyclic voltabsorptogram, DCVA)) were deduced for few selected wavelengths to characterize the optical properties. The changes in the electrochromic characteristics (in the visible region) of the composite is attributed mainly to transition of Ru(III) to Ru(IV). SEM images revealed the presence of smaller sized particles of hydrous ruthenium oxide in the composite film. The existence of smaller size RuO 2 particles having more active surface area is the reason for the enhanced capacitance and optical properties.

We have fabricated an electrochromic (EC) device with poly(2,5-dimethoxyaniline), PDMA, entrapped in poly(styrene sulfonic acid) (PSS) as an electrochromic layer. The device showed improved performances like stability, optical contrast, etc., over the device with a PDMA layer doped by H 2 SO 4 . In the process of fabrication of the EC device with a sandwich configuration, indium tin oxide (ITO)/PDMA–PSS||poly(ethyleneimine) (PEI)/orthophosphoric acid (H 3 PO 4 )/WO 3 /ITO, electrochemical polymerization of 2,5-dimethoxyaniline (DMA) was performed with PSS as electrolyte and ITO coated glass as working electrode. The performance characteristics of EC device, like optical contrast, stability, switching time, etc., were followed by cyclic voltammetry, double potential step chronoamperometry and in-situ spectroelectrochemistry. The device was operated in between − 1 V and + 1 V, and absorption characteristics were followed by in-situ UV–visible spectroscopy. A visible contrast in color upon switching the potential from − 1 V to + 1 V was noticed for the device. The device was pale yellow at − 1 V and dark green at + 1 V. Incorporation of PSS into PDMA resulted enhancement in the performance of the complementary electrochromic device. The optical contrast of the device was improved by incorporating PSS into PDMA matrix. The device retained nearly 50% of their optical contrast after 10,000 double steps informing the superior performance of PDMA–PSS in the EC device.

Polyaniline (PANI) was doped with poly(styrene sulfonic acid) (PSS) via doping–dedoping–redoping procedure. Incorporation of PSS in PANI resulted modifications in electrochemical and electrochromic properties, morphology and polymer structure of the polymer film as evidenced by the results of cyclic voltammetry, in situ UV–vis spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis and conductivity measurements. PANI doped with PSS was found to have a cross-link/branched structure with a minimum degradation product. The absence of degradation products improves the electrochemical, electrochromic properties and thermal stability of the PANI layer for electrochromic applications.

Silver nanoparticles were formed in situ along with poly(2,5-dimethoxyaniline) (PDMA) in an interconnected network matrix (reactor), comprising the electronic conductive polymer, PDMA, and a polyelectrolyte, poly(styrene sulfonic acid) (PSS), through the simultaneous reduction of Ag+ ions and polymerization of 2,5-dimethoxyaniline. In situ ultraviolet-visible spectroscopy showed that peaks corresponding to the plasmon resonance of silver nanoparticles at 411 nm and the polaronic transition of PDMA at 438 nm provided evidences for the simultaneous formation of silver nanoparticles and PDMA. Transmission electron microscopy and size distribution analysis revealed the presence of spherical silver nanoparticles with an average diameter of 12 nm in the composite. X-ray photoelectron spectroscopy showed that the amine units in PDMA changed to imine units upon the formation of silver nanoparticles. A comprehensive mechanism for the formation of the PDMA-PSS-Ag nanocomposite is proposed. A 10-fold increase in the conductivity was noticed for the PDMA–PSS–Ag nanocomposite (1 S/cm) in comparison with the PDMA–PSS composite (0.1 S/cm). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3843–3852, 2006

Poly(2,5-dimethoxyaniline) (PDMA)-Ag composites were successfully obtained through the oxidative polymerization of 2,5-dimethoxyaniline in poly(styrene sulfonic acid) with cH 3 SO 3 Ag and AgNO 3 as oxidants. In situ ultraviolet-visible spectroscopy results showed that the growth rate of PDMA was strongly affected by CH 3 SO 3 - and NOR 3 - . The coupling reaction of PDMA and NO - 3 was proposed to explain the lower growth rate of PDMA with AgNO 3 as the oxidant in comparison with CH 3 SO 3 Ag. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to validate the proposed coupling reaction through the monitoring of the side products and oxidized state of PDMA. The results showed that there were more side products and lower oxidized states for the composite structure in the presence of NO - 3 than in the presence of CH 3 SO - 3 , and this agreed with the proposal. Transmission electron microscopy showed that the Ag nanoparticles had almost the same size, regardless of the anions.

Waterborne polyurethane (WPU) was spin-coated on indium tin oxide (ITO) coated glass. Poly(2,5-dimethoxyaniline) (PDMA) was deposited using electrochemical polymerization as conducting composite film on the above WPU/ITO electrode and used as an electrode in an electrochromic device assembly. Tungsten oxide (WO 3 ) coated ITO glass was used as the other electrode with LiClO 4 doped gelled polyethylene oxide (PEO) as polymer electrolyte. The configuration of an electrochromic device was assembled: ITO/WPU-PDMA||LiClO 4 -PC-PEO (400,000)||WO 3 /ITO, where PC represents propylene carbonate. The characterization of the single electrodes, ITO/WPU-PDMA composite, ITO/WO 3 , and the device was performed by using cyclic voltammetry. The columbic efficiency (CE) of the ITO/WPU-PDMA composite and ITO/WO 3 electrodes were close to 100%. The optical contrast of the single electrodes and the device were determined by UV–vis spectroelectrochemical studies. A visible contrast in color upon switching the potential from −1.50 to +1.50 V was noticed for the device. The device was pale yellow at −1.5 V and dark green at +1.5 V. The CE of the device was 91%. Double potential chronamperomtry was used to determine the response time of coloring and bleaching processes. The bleaching process was found to be faster than coloring. The stability of the device was established by polarizing the device and recording the UV–vis spectrum in open circuit conditions. Bleaching state is more stable than coloring state.

Poly(o-methoxyaniline) (POMA) and poly(2,5-dimethoxyaniline) (PDMA) were used for fabricating Schottky diode devices with sandwich structure, as Al/POMA/indium tin oxide (ITO) coated glass and ITO/PDMA/Al. These devices exhibit rectifying behavior with differences in performance parameters like turn on voltage of the device, barrier height and saturation current density. A close comparison of the current (I)–voltage (V) characteristics reveals such differences. Cyclicvoltammetry and UV-Vis spectroscopy of POMA and PDMA films were used to obtain electrochemical and optical properties of the polymers and discussed in support of the observed differences in the electronic properties of the devices fabricated with POMA/PDMA.

Copolymerization of 2,2′-dithiodianiline (DTDA) and aniline (An) was performed electrochemically by cyclic voltammetry on Pt electrode in 1 M HCl. The copolymerization rate is strongly dependent on the amount of DTDA in the comonomer feed. The composition of the copolymeric films were determined by X-ray photoelectron spectroscopy (XPS) and were controlled by changing comonomer feed ratios. The fraction of DTDA units in the copolymers is proportional to the fraction of DTDA in the comonomer feeds. The reactivity of An decreases by increasing the amount of DTDA in the comonomer feed. Scanning electron microscopy (SEM) photographs show that there exist clear differences in morphology of the polymer films at various DTDA concentrations.

The electrochromic characteristics of poly(2,5-dimethoxy aniline) (PDMA), have been evaluated using cyclic voltammetry, in situ UV–visible (UV–VIS) spectroscopy, cyclic spectrovoltammetry and spectrochronoamperometry. The results from cyclic voltammetry revealed that PDMA could be easily transformed from leucoemeraldine to emeraldine state in comparison with polyaniline (PANI). The conversion of reduced PDMA form into fully oxidized state could occur at a lower positive potential for PDMA than PANI (0.70 V for PANI and 0.27 V for PDMA). UV–VIS spectrum of PDMA showed three optical transitions at λ max =375 nm (I), 460 nm (II) and 770 nm (III). The electrochemical transitions of PDMA while cycling the potentials were simultaneously monitored through UV–VIS spectroscopy. Results of cyclic spectrovoltammetry experiments revealed that the band at λ max II =460 nm corresponds to intermediate state between leucoemeraldine and emeraldine forms of PDMA. Hysteresis were noticed in the absorbance-potential profile for λ max =375, 460 and 770 nm. The derivative cyclicvoltabstogram (DCVA) deduced from spectrovoltammetry reveals the presence of residual absorbance at E =0.0 V for PDMA. A linear correlation was noticed between half intensity of absorbance ( E 1/2 A ) at the wavelength 375, 460 and 770 nm and scan rate ( ν ). Electrochromic properties of PDMA like optical contrast, columbic efficiency and electrochromic efficiency are reported.

Electrochemical copolymerization of aniline (ANI) with dithiodianiline (DTDA), an aniline derivative containing –S–S– links was carried out in 2 M H 2 SO 4 using cyclic voltammetry. The cyclicvoltamogram (CV) of the deposited copolymer was recorded in monomer free background electrolyte. A close comparison of the CV characteristics of the films deposited during polymerization of mixture of ANI and DTDA clearly the copolymer deposition. The UV–VIS spectroscopy, spectroelectrochemical studies, thermal analysis and FTIR spectroscopic analysis were used to identify the differences between the copolymer and PANI in the optical, thermal properties and structure. The copolymer was found to have a branched structure in comparison with PANI. The copolymer exhibit different colors upon changing applied potentials.

In situ UV-Visible spectroelectrochemical studies on the copolymerization of diaminobenzenesulfonic acid (DABSA) with aniline (ANI), o-toluidine (OT) and N-methyl aniline (NMA) were carried out potentiostatically in aqueous 1.0 M H2SO4 solutions containing the mixture of monomers (DABSA and ANI/OT/NMA) at an optically transparent electrode. Copolymerization studies were performed for different feed ratios of the comonomers. Polymerization of DABSA was also carried out to bring out the differences in the spectral characteristics between homopolymerization and copolymerization. UV-Visible spectra were recorded at various timer intervals during copolymerization and homopolymerization of DABSA. Four absorption bands were noticed for the copolymerization in contrast to the three bands for homopolymerization. The appearance of bands at 672, 633 and 668 nm for copolymerization of DABSA with ANI, OT and NMA, respectively, are attributed to the exitonic transitions associated with these monomer units in the copolymer. The exitonic band of PANI/PANI derivative units that appeared during copolymerization was markedly influenced by the presence of sulfonic acid groups in the copolymer. This was demonstrated by observing its influence in the absence of applied potential and also by following the changes in the band positions through spectroelectrochemical studies on the copolymerization of DABSA with ANI or OT or NMA. The dependences of absorbances on time at the wavelengths corresponding to polaronic and exitonic transitions of the polymers were deduced. The decrease in absorbances of the exitonic band arising from the dedoping caused by sulfonic acid groups in the polymer showed variations in the copolymerization of DABSA with ANI, OT and NMA. The following trend was noticed ANI>NMA>OT.

The title compounds were synthesized by coupling a toluene solution of Me 3 SiSiMe 2 Cl and Cl(SiMe 2 ) 6 Cl with sodium-potassium alloy. The 1 H, 13 C, and 29 Si NMR spectra of Si10 were fully assigned by 2D 1 H- 13 C and 1 H- 29 Si NMR spectroscopy; the latter method is useful for obtaining Si-Si as well as Si-H connectivities. Si-Si coupling constants for Si10 were determined with use of INEPT-INADEQUATE NMR spectroscopy

An investigation of the UV absorption and emission properties of n-Si 16 Me 34 in room- and low-temperature solutions revealed a striking similarity to the photophysical behavior of high molecular weight peralkylated polysilanes. The absorption is that expected for a statistical collection of chromophoric segments. Room-temperature emission is that expected from the lowest excitation energy conformations of approximately 16-silicon chains, presumably all-trans. Their excited states are believed to be generated by energy transfer in the polymer and by adiabatic conformational transitions in the hexadecasilane.

The title compounds were synthesized by coupling a toluene solution of Me 3 SiSiMe 2 Cl and Cl(SiMe 2 ) 6 Cl with sodium-potassium alloy. The 1 H, 13 C, and 29 Si NMR spectra of Si10 were fully assigned by 2D 1 H- 13 C and 1 H- 29 Si NMR spectroscopy; the latter method is useful for obtaining Si-Si as well as Si-H connectivities. Si-Si coupling constants for Si10 were determined with use of INEPT-INADEQUATE NMR spectroscopy

Liquid phase deposition (LPD) method to grow the silicon dioxide interlayer on the PES plastic substrates with the O2/Ar plasma pre-treatment is investigated. After which, the interlayer on the plastic substrates is grown and the films' quality on the substrates with or without the plasma pre-treatment is examined by using scanning electron microscopy, etching rate of the oxide layer by the diluted HF solution and surface leakage current measurement. The pentacene-based organic thin film transistors on the dielectric layers suitable for flexible electronics applications are demonstrated

Etk/Bmx, a member of the Tec family of tyrosine kinases, mediates various signaling pathways and confers several cellular functions. In the present study, we have explored the functional role of Etk in mediating EGF-induced apoptosis, using MDA-MB-468 cell line as a model. We first demonstrated that EGF treatment induces Etk tyrosine phosphorylation in both HeLa and MDA-MB-468 cells. Overexpression of Etk by recombinant adenovirus in MDA-MB-468 cells potentiates the extent of EGF-induced cell apoptosis. The observed Etk-enhanced MDA-MB-468 cell apoptosis is associated with the Stat1 activation, as demonstrated by electrophoresis mobility shift assays and reporter gene assays. By contrast, a kinase domain deletion mutant EtkDeltaK, functioning as a dominant-negative mutant, ameliorates EGF-induced Stat1 activation and apoptosis in MDA-MB-468 cells. To explore whether the activated Etk alone is sufficient for inducing apoptosis, a conditionally activated Etk (DeltaEtk-ER), a chimeric fusion protein of PH domain-truncated Etk and ligand-binding domain of estrogen receptor, was introduced into MDA-MB-468 cells. Upon beta-estradiol ligand activation, the DeltaEtk-ER could stimulate Stat1 activity and confer cell apoptosis independent of EGF treatment. Taken together, our findings indicate that Etk is a downstream signaling molecule of EGF receptor and suggest that Etk activation is essential for transducing the EGF-induced apoptotic signaling.

Pentacene-based highly transparent thin-film transistors which are fabricated by inserting a thin insulating lithium fluoride layer between pentacene and transparent source/drain electrodes are presented. Through this method, device performance can be enhanced dramatically with an average transmittance of as high as 69.72% in the visible region, indicating that the LiF layer is not responsible for optical transmission. For example, there is a significant improvement of a few times with the introduction of the 1-nm-thick LiF layer, the maximum saturation drain current and the field-effect mobility. These improvements are attributed to the energy band realignment and the tunneling process.

The electrical characteristics of a field-effect transistor (FET) using bilayer water-soluble polymer electrolytes/conjugated polymer, that is, poly(ethyleneimine) (PEI)/polyaniline (PANI) doped with camphor sulfonic acid (CSA) structure, are discussed. The NH3+ cations from PEI were stuffed into the PANI-CSA to dedope nitrogen (imine) by applying gate voltage, and this results in the achievement of transistor behavior in drain current modulation. The PANI-CSA/PEI-based organic FETs working in depletion mode with a high field-effect mobility of ∼2.48cm2∕Vs at atmosphere conditions are demonstrated.

The conjugated polymer poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT-PSS) is usually applied in fabricating electrodes of devices. In this work, the applications to organic a thin film transistor with the introduction of poly(ethyleneimine) (PEI) into the PEDOT-PSS are investigated. The conductivity of PEDOT-PSS can be reduced by incorporating PEI into PEDOT-PSS, which can be applied as an active layer instead of electrodes for devices application. Based on the PEDOT-PSS blended with PEI, the fabricated devices posses a depletion-mode transistor behavior with the on/off ratio of about 103 is used. Meanwhile, the role of PEI in PEDOT-PSS to modulate the channel conductivity is discussed.

The liquid-phase deposition method for growing silicon dioxide interlayers on O2∕Ar plasma pretreatment plastic substrates is investigated. The authors found that the ratio of COO (288.9eV) to CH2(284.5eV) increases with the O2∕Ar plasma pretreatment as indicated by x-ray photoelectron spectroscopy. Upon treatment, the interlayer on the plastic substrate is grown, and the quality of the film on the substrate with or without plasma pretreatment is examined by using scanning electron microscopy, etching rate of the oxide layer by dilute HF solution, and surface leakage current measurement. Pentacene-based organic thin-film transistors on dielectric layers are demonstrated. Finally, they also found that this coating can enhance optical transmittance, as demonstrated by ultraviolet-visible spectroscopy measurement.

This work presents an organic thin film transistor using double polymer layers, polymer electrolyte/conjugated polymer, i.e., poly(diallyldimethylammonium chloride) (PDDA)/poly(diphenylamine) (PDPA) structure. The single mobile anions (Cl−) pending on the PDDA are stuffed into the conjugated polymer to dope the nitrogen atoms (imine) by applying the gate bias, resulting a higher drain current under the same source-drain voltage. The PDDA/PDPA polymer structure working in the enhancement mode which operates under atmospheric conditions as a typical p-channel transistor is demonstrated.

Electrochemical synthesis of the copolymer of aniline with dithiodianiline, an aniline derivative containing-S-S-links in it, was carried out in 2 M by cyclic voltammetry (CV). In addition, CV was used to evaluate the differences between the electrochemical characteristics associated with growth of the copolymer and polyaniline (PANI). The deposition of copolymeric film was evident from the observed changes in growth rate, redox potentials, and transport mechanisms of deposited films in contrast to PANI. Plausible reaction schemes are proposed on the basis of CV results for the copolymerization. This involves the possible branched structure for the copolymer and corroborated with other characterizations. X-ray photoelectron spectroscopy and scanning electron microscopy were used to determine the nitrogen and sulfur content and the morphological behavior of the copolymer, respectively. The results show that the copolymer possesses a different charge transport mechanism in films and a branched structure as a consequence of incorporation of DTDA units resulting in -S-S- links in the polyaniline structure. © 2001 The Electrochemical Society. All rights reserved.