Superhydrophobic silane/graphene oxide (GO) composite coating with excellent anti-corrosion performance and durability was successfully synthesized on copper surface using simple dipping and ...subsequent curing procedure. ATR-FTIR spectroscopy, Raman spectra, X-ray photoelectron spectroscopy and scanning electron microscopy were applied to investigate the structure and morphology of the prepared superhydrophobic silane/GO composite coating. Results suggested the covalent reaction between silane and GO nanosheets to form a more protective and durable coating. Electrochemical methods were conducted to research the anti-corrosion properties of the prepared silane/GO composite coating in 1 M NaCl solution. Potentiodynamic polarization curves indicated that both the cathodic and anodic reaction was inhibited and the corrosion current density decreased more than two orders of magnitude compared to the bare copper substrate. Electrochemical impedance spectroscopy suggested that the prepared superhydrophobic silane/GO composite coating possessed the largest impedance modulus and the protection efficiency was over 99% after exposed to 1 M NaCl solution 120 h. The good protection property and durability, along with the facile preparation route, implies a significant prospect for practical applications.
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•Superhydrophobic silane/GO coating was fabricated on copper by using a facile route.•GO covalently reacted with silane to form a dense and continuous coating.•The silane/GO coating exhibited much higher corrosion resistance in 1 M NaCl solution.•The silane/GO coating showed good stability and durability.
Abstract Our aim was to differentiate IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis by analysing clinical, radiographic, and pathological ...features. Fifty-five patients, 50, and 50 were enrolled, respectively and their baseline characteristics and serological, sialographic, and pathological findings compared. The male:female ratio for IgG4-related sialadenitis was 1:1.2 for primary Sjögren syndrome 1:15.7, and for chronic obstructive submandibular sialadenitis1:0.92. Numbers with enlarged salivary glands were 55, 16, and 50; with xerostomia 26, 48, and 0; with a history of allergy 26, 4, and 6, and with coexisting systemic disease 12, 19, and 0 (p = 0.14). Mean (SD) serum IgG4 concentrations were 109.1 (97.9), 4.9. (1.9) g/L, and 5.3 (1.6) g/L, p < 0.001 in all cases. Sialography showed enlargement of the gland, dilatation of the duct, and slightly decreased secretory function in IgG4-related disease; obvious sialectasia and decreased secretory function in Sjögren syndrome; and dilatation of Wharton’s duct and filling defects in obstructive sialadenitis. Histopathological examination showed lymphoplasmacytic infiltration with storiform fibrosis, lymphoplasmacytic inflammation and lymphoepithelial lesions, and dilatation of the duct with epithelial metaplasia in the three groups, respectively. The number of IgG4-positive plasma cells was 123 (45)/HPF, 8 (3)/HPF, and 5 (4)/HPF, while the IgG4-/IgG-positive cell ratio was 71.7 (13.9)%, 4.6 (2.5)%, 18.9 (19.7)%, respectively (p < 0.001). The three conditions have different clinical, radiographic, and pathological features that provide important clues to the differential diagnosis. Serological and histological tests are important, and comprehensive consideration is necessary.
A Nafion and poly(3,4-ethylenedioxythiophene) (PEDOT) containing composite polymer has been electropolymerized on carbon-fiber microelectrodes with the goal of creating a mechanically stable, ...robust, and controllable electrode coating that increases the selectivity and sensitivity of in vivo electrochemical measurements. The coating is deposited on carbon-fiber microelectrodes by applying a triangle waveform from +1.5 V to −0.8 V and back in a dilute solution of ethylenedioxythiophene (EDOT) and Nafion in acetonitrile. Scanning electron microscopy demonstrated that the coating is uniform and ∼100 nm thick. Energy-dispersive X-ray spectroscopy demonstrated that both sulfur and fluorine are present in the coating, indicating the incorporation of PEDOT (poly(3,4-ethylenedioxythiophene) and Nafion. Two types of PEDOT:Nafion coated electrodes were then analyzed electrochemically. PEDOT:Nafion-coated electrodes made using 200 μM EDOT exhibit a 10–90 response time of 0.46 ± 0.09 s versus 0.45 ± 0.11 s for an uncoated fiber in response to a 1.0 μM bolus of dopamine. The electrodes coated using a higher EDOT concentration (400 μM) are slower with a 10–90 response time of 0.84 ± 0.19 s, but display increased sensitivity to dopamine, at 46 ± 13 nA/μM, compared to 26 ± 6 nA/μM for the electrodes coated in 200 μM EDOT and 13 ± 2 nA/μM for an uncoated fiber. PEDOT:Nafion-coated electrodes were lowered into the nucleus accumbens of a rat, and both spontaneous and electrically evoked dopamine release were measured. In addition to improvements in sensitivity and selectivity, the coating dramatically reduces acute in vivo biofouling.
Thermally stimulated depolarization current (TSDC) related internal electric field (Eint) is found to influence the pyrocurrent of multiferroics greatly, but its effect on the pole current of ...magnetoelectric (ME) materials has never been studied. In this article, ME antiferromagnet tetracobalt diniobate is cooled under an external electric field (Eext) from 125 K to generate the TSDC related Eint. Under a magnetic field (H), the pole current while cooling in the presence of Eint and Eext, and the subsequent pyrocurrent while heating without applying Eext is studied. Competition between Eext and Eint induces multiple transitions of pole current, and some transitions gradually disappear with increasing H. The pyrocurrent shows three transitions that are ascribed to the domain switching by Eint, depolarization of negative and positive domains, respectively. With increasing H, the transition at the highest temperature gradually disappears, indicating that the polarization is easier to be switched under a stronger H, which is explained both from the aspects of electrostatic potential energy and the special magnetic structure responsible for magnetoelectricity.
•Memory effect of ME coupling in Co4Ta2O9 is revealed in the form of polarization memory effect: ME poling induced polarization below Néel temperature is recovered after Co4Ta2O9 is heated to ...paramagnetic nonpolar phase and then cooled to antiferromagnetic polar phase without being poled.•Polarization memory effect is attributed to polar nanoregions in paramagnetic phase due to short-range magnetic ordering as evidenced by heat capacity data deduced magnetic entropy.•If the applied magnetic field in paramagnetic phase is weakened, polarization memory effect is enhanced, which is ascribed to the less change of spin structure. If we switch the direction of this magnetic field, the polarization after reentering antiferromagnetic phase is also reversed.•ME coupling memory effect is also reflected in electric field dependent magnetization after the second cooling process without being poled. The two aspects of ME coupling are strongly correlated.
Memory effect of magnetoelectric (ME) coupling is observed in antiferromagnetic Co4Ta2O9 ME poling generated polarization below Néel temperature is retrieved after Co4Ta2O9 is warmed to paramagnetic phase and then cooled to antiferromagnetic phase without being poled. This effect is ascribed to polar nanoregions in paramagnetic phase due to short range magnetic ordering as evidenced by temperature dependent magnetic entropy. If the applied magnetic field in paramagnetic phase is weakened, the memory effect is strengthened, which is ascribed to the less change of spin alignment induced by the weaker magnetic field. If we switch this magnetic field, the polarization when reentering polar phase is also reversed. Furthermore, the memory effect is also reflected in electric field dependent magnetization after the second cooling process without being poled.
Abstract Stable interconnection to neurons in vivo over long time-periods is critical for the success of future advanced neuroelectronic applications. The inevitable foreign body reaction towards ...implanted materials challenges the stability and an active intervention strategy would be desirable to treat inflammation locally. Here, we investigate whether controlled release of the anti-inflammatory drug Dexamethasone from flexible neural microelectrodes in the rat hippocampus has an impact on probe-tissue integration over 12 weeks of implantation. The drug was stored in a conducting polymer coating (PEDOT/Dex), selectively deposited on the electrode sites of neural probes, and released on weekly basis by applying a cyclic voltammetry signal in three electrode configuration in fully awake animals. Dex-functionalized probes provided stable recordings and impedance characteristics over the entire chronic study. Histological evaluation after 12 weeks of implantation revealed an overall low degree of inflammation around all flexible probes whereas electrodes exposed to active drug release protocols did have neurons closer to the electrode sites compared to controls. The combination of flexible probe technology with anti-inflammatory coatings accordingly offers a promising approach for enabling long-term stable neural interfaces.
We propose a new class of tensor-network states, which we name projected entangled simplex states (PESS), for studying the ground-state properties of quantum lattice models. These states extend the ...pair-correlation basis of projected entangled pair states to a simplex. PESS are exact representations of the simplex solid states, and they provide an efficient trial wave function that satisfies the area law of entanglement entropy. We introduce a simple update method for evaluating the PESS wave function based on imaginary-time evolution and the higher-order singular-value decomposition of tensors. By applying this method to the spin-1/2 antiferromagnetic Heisenberg model on the kagome lattice, we obtain accurate and systematic results for the ground-state energy, which approach the lowest upper bounds yet estimated for this quantity.
Relief of pain is rewarding. Using a model of experimental postsurgical pain we show that blockade of afferent input from the injury with local anesthetic elicits conditioned place preference, ...activates ventral tegmental dopaminergic cells, and increases dopamine release in the nucleus accumbens. Importantly, place preference is associated with increased activity in midbrain dopaminergic neurons and blocked by dopamine antagonists injected into the nucleus accumbens. The data directly support the hypothesis that relief of pain produces negative reinforcement through activation of the mesolimbic reward-valuation circuitry.
•Non-Fourier heat conduction and non-Fick diffusion of moisture.•Hyperbolic diffusion of hygrothermal coupling in an elastic cylinder.•Transient response of a cylinder subject to heat/moisture ...shock.•Phase lag of heat and moisture flux strongly affects hygrothermal stresses.
The classical theory of heat conduction (Fourier theory) predicts an infinite speed for thermal disturbance propagation, which is physically unrealistic. By extending the classical Fourier heat conduction and Fick’s diffusion, this paper presents a hyperbolic diffusion law with different phase lags of thermal and moisture fluxes to simulate coupled heat-moisture diffusion-propagation behavior. Transient hygrothermal and elastic response of an infinitely long cylinder subjected to sudden hygrothermal loadings at the surface is studied. By using Laplace transform and decoupling technique, a closed form solution of temperature, moisture, displacements and stresses is determined. The analytical results show that the thermal and moisture relaxation times or phase lags of heat and moisture fluxes play a significant role in the early stage of transient response after heat/moisture shock. The classical results corresponding to vanishing phase lags can be recovered from the present ones. For non-vanishing phase lags, hygrothermal waves have finite propagation speeds. Numerical results are calculated and displayed graphically to show the influence of the phase lags of heat and moisture fluxes on transient hygrothermoelastic fields. A comparison between classic model and hyperbolic hygrothermal coupling model is given. Based on the non-Fourier heat conduction and non-Fick diffusion, some shortcomings induced by the classical Fourier’s and Fick’s laws can be effectively avoided.
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