Effect of Mn substitution on the oxidation/adsorption abilities of iron(III) oxyhydroxides

In this study, divalent manganese ions [Mn(II)] were substituted a part of divalent iron ions [Fe(II)] present in Fe oxyhydroxides to prepare novel composites (Mn@Feox). The composites were prepared by (1) simultaneous hydrolysis of Fe(II) and Mn(II), and (2) rapid oxidation with H₂O₂. The resulting Mn@Feox prepared with different molar ratios of Fe and Mn was characterized and evaluated for their abilities to adsorb arsenic species [As(III) and As(V)] in aqueous solution. X-ray diffraction and field emission transmission electron microscope analyses revealed Mn@Feox has a δ-(Fe_1?x, Mn_x)OOH-like structure with their mineralogical properties resembling those of feroxyhyte (δ-FeOOH). The increase in Mn substitution in Mn@Feox enhanced the oxidative ability to oxidize As(III) to As(V), but it decreased the adsorption capacity for both arsenic species. The optimal Mn/Fe molar ratio that could endow oxidation and magnetic capabilities to the composite without significantly compromising As adsorption capability was determined to be 0.1 (0.1Mn@Feox). The adsorption of As(III) on 0.1Mn@Feox was weakly influenced by pH change while As(V) adsorption showed high dependence on pH, achieving nearly complete removal at pH?<?5.7 but gradual decrease at pH?>?5.7. The adsorption kinetics and isotherms of As(III) and As(V) showed good conformity to pseudo-second-order kinetics model and Freundlich model, respectively.     

Atomic disorders in layer structured topological insulator SnBi<Subscript>2</Subscript>Te<Subscript>4</Subscript> nanoplates

Identification of atomic disorders and their subsequent control has proven to be a key issue in predicting, understanding, and enhancing the properties of newly emerging topological insulator materials. Here, we demonstrate direct evidence of the cation antisites in single-crystal SnBi₂Te₄ nanoplates grown by chemical vapor deposition, through a combination of sub-ångström-resolution imaging, quantitative image simulations, and density functional theory calculations. The results of these combined techniques revealed a recognizable amount of cation antisites between Bi and Sn, and energetic calculations revealed that such cation antisites have a low formation energy. The impact of the cation antisites was also investigated by electronic structure calculations together with transport measurement. The topological surface properties of the nanoplates were further probed by angle-dependent magnetotransport, and from the results, we observed a two-dimensional weak antilocalization effect associated with surface carriers. Our approach provides a pathway to identify the antisite defects in ternary chalcogenides and the application potential of SnBi2Te4 nanostructures in next-generation electronic and spintronic devices.

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Surface-enhanced Raman scattering nanosensors for <Emphasis Type="Italic">in vivo</Emphasis> detection of nucleic acid targets in a large animal model

Although nanotechnology has led to important advances in in vitro diagnostics, the development of nanosensors for in vivo detection remains very challenging. Here, we demonstrated the proof-of-principle of in vivo detection of nucleic acid targets using a promising type of surface-enhanced Raman scattering (SERS) nanosensor implanted in the skin of a large animal model (pig). The in vivo nanosensor used in this study involves the “inverse molecular sentinel” detection scheme using plasmonics-active nanostars, which have tunable absorption bands in the near infrared region of the “tissue optical window”, rendering them efficient as an optical sensing platform for in vivo optical detection. Ex vivo measurements were also performed using human skin grafts to demonstrate the detection of SERS nanosensors through tissue. In this study, a new core–shell nanorattle probe with Raman reporters trapped between the core and shell was utilized as an internal standard system for self-calibration. These results illustrate the usefulness and translational potential of the SERS nanosensor for in vivo biosensing.

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A Hemispherical Image Sensor Array Fabricated with Organic Photomemory Transistors

Hemispherical image sensors simplify lens designs, reduce optical aberrations, and improve image resolution for compact wide-field-of-view cameras. To achieve hemispherical image sensors, organic materials are promising candidates due to the following advantages: tunability of optoelectronic/spectral response and low-temperature low-cost processes. Here, a photolithographic process is developed to prepare a hemispherical image sensor array using organic thin film photomemory transistors with a density of 308 pixels per square centimeter. This design includes only one photomemory transistor as a single active pixel, in contrast to the conventional pixel architecture, consisting of select/readout/reset transistors and a photodiode. The organic photomemory transistor, comprising light-sensitive organic semiconductor and charge-trapping dielectric, is able to achieve a linear photoresponse (light intensity range, from 1 to 50 W m⁻²), along with a responsivity as high as 1.6 A W⁻¹ (wavelength = 465 nm) for a dark current of 0.24 A m⁻² (drain voltage = −1.5 V). These observed values represent the best responsivity for similar dark currents among all the reported hemispherical image sensor arrays to date. A transfer method was further developed that does not damage organic materials for hemispherical organic photomemory transistor arrays. These developed techniques are scalable and are amenable for other high-resolution 3D organic semiconductor devices.     

A Location Management Scheme Supporting Route Optimization for Mobile Hosts

Using the Internet as a foundation for wirelessnetworking, there is currently a great deal of interestin providing IP networking support for mobile hosts. Asa result of IPs reliance on the entire Internet address for host identification, most proposalsdepend on a default route through the mobile host's homeaddress, which makes for unnecessarily long routes. Thispaper introduces two concepts, localregion and patron service, based on thelocality features of host moving and calling patterns.It then shows how these concepts work together torealize a location management scheme for achievingoptimal routing for most traffic while restricting costlylocation propagation. The proposed scheme wasimplemented using a network simulator and evaluated fromrouting effectiveness point of view, as compared withits location overhead.     

Localization of atrial natriuretic peptide receptors in the rat tongue and hard palate

The effect of a naturally occurring plant phenolic constituent (the acylphloroglucinol derivative, jensenone, derived from Eucalyptus jensenii) on the food intake of two folivorous marsupials, the common ringtail (Pseudocheirus peregrinus) and the common brushtail possum (Trichosurus vulpecula) was studied. When fed diets containing varying concentrations of jensenone, both species regulated their intake of jensenone so as not to exceed a ceiling intake. This ceiling was about twice as high for common ringtails as for common brushtails from northern Australia. Southern populations of common ringtails showed greatly reduced capacities to tolerate jensenone. When common brushtails were injected (0.5 mg.kg-0.75 body mass) with ondansetron (a selective antagonist of serotonin 5HT3 receptors), they ate significantly more jensenone than animals injected with physiological saline. The same pattern was observed when common ringtails were fed diets containing both jensenone and ondansetron (0.0035 mg.g-1 wet mass of diet). Ondansetron injection had no effect on food intake when the food did not contain jensenone while the addition of higher doses of ondansetron to diets of common ringtails very slightly reduced food intakes of a non-jensenone diet. When common brushtails were given 50 mg of jensenone by gastric lavage, their average subsequent intake of dietary jensenone matched the difference between the daily threshold and the dose given, although the response of individuals was highly variable. Lavage with water alone had no effect on subsequent jensenone intake compared with the pre-dose period. We interpret these results as evidence that the antifeedant effects of jensenone and related compounds are partly mediated by serotonin action on 5HT3 receptors most likely via "nausea" to condition a food aversion.     

Optical inhomogeneity and microstructure of ZrO(2) thin films prepared by ion-assisted deposition

The index inhomogeneity and the microstructure of ZrO(2) films prepared by Ar-ion-assisted deposition are investigated. The results show that as the Ar-ion momentum transferred to the growing film increases, the average refractive index increases, the vacuum-to-air spectral shift becomes almost zero, the sign of relative inhomogeneity transits from negative to positive, and the void fraction of the top layer next to air becomes smaller than that of the bottom one. These optical properties result from the improved packing density and denser outer region next to air. The Ar-ion bombardment also induces the changes in microstructure of ZrO(2) films, such as the preferential (111) orientation of cubic phase, increase in compressive stress, and reduction of surface roughness.