Rational and Facile Construction of 3D Annular Nanostructures with Tunable Layers by Exploiting the Diffraction and Interference of Light

This paper reports a rational and facile approach to fabricating arrays of 3D annular nanostructures with tunable layers by utilizing the diffraction and interference of UV light. Based on discretized Fresnel bright spots and standing waves formed within a photoresist film, the structures with nanoscale features are realized using simple, conventional photolithography. The 3D annular nanostructures are produced in arrays of single‐, double‐, and triple‐layered ring structures with the height of single layer on a 100 nm scale. The structural formation process and features of the nanostructures are analyzed and explained through 3D modeling that integrates the effects of both UV exposure dose and chemical kinetics. The approach to generating 3D annular nanostructures with tunable layers and discrete heights can be adapted for various applications that require the 3D structures fabricated over a large area with high throughput.     

Efficient bridgeless PFC converter with reduced voltage stress

An efficient bridgeless power factor correction converter with reduced voltage stress is proposed. In the proposed converter, the input full‐bridge rectifier is removed to reduce the conduction loss of rectification, and the voltage stress of switching devices is significantly reduced by utilizing the additional circuit composed of a capacitor and a diode. Therefore, low‐voltage‐rating diodes with less forward voltage drop and low‐voltage‐rating Metal‐Oxide‐Semiconductor Field‐Effect Transistor (MOSFET) with low R_DS(on) is utilized. The proposed converter is based on the single‐ended primary‐inductor converter power factor correction operation in discontinuous conduction mode to achieve a high power factor with a simple control circuit. Consequently, the proposed converter can provide a high power factor and a high power efficiency, and it is also suitable for low‐cost converter for high input/output voltage system. The operational principles, steady‐state analysis, and design equations of the proposed converter are described in detail. Experimental results are verified for a 130 W prototype at a constant switching frequency 100 kHz. Copyright © 2015 John Wiley & Sons, Ltd.     

Noninvasive Transdermal Vaccination Using Hyaluronan Nanocarriers and Laser Adjuvant

Vaccines are commonly administered by injection using needles. Although transdermal microneedles are less invasive promising alternatives, needle‐free topical vaccination without involving physical damage to the natural skin barrier is still sought after as it can further reduce needle‐induced anxiety and is simple to administer. However, this long‐standing goal has been elusive since the intact skin is impermeable to most macromolecules. Here, we show an efficient, noninvasive transdermal vaccination by employing two key innovations: the use of hyaluronan (HA) as vaccine carriers and non‐ablative laser adjuvants. Conjugates of a model vaccine ovalbumin (OVA) and HA—HA–OVA conjugates—induced more effective maturation of dendritic cells in vitro, compared to OVA. Following topical administration in the skin, HA–OVA conjugates penetrated into the epidermis and dermis in murine and porcine skins, as revealed by intravital microscopy and fluorescence assay. Topical administration of HA‐OVA conjugates significantly elevated both humoral and mucosal antibodies, with peak levels at four weeks. An OVA challenge at week eight elicited strong immune‐recall responses. With pretreatment of the skin using non‐ablative fractional laser beams as adjuvant, strong immunization was achieved with much reduced doses of HA–OVA (1 mg kg^–1 OVA). Our results demonstrate the potential of the noninvasive patch‐type transdermal vaccination platform.     

A Novel Complex Orthogonal Design for Space–Time Coding in Sensor Networks

In this paper, we propose a complex orthogonal design based on the theory of Finite projective plane. As most of the orthogonal designs incur low ratio of time diversity, the proposed complex orthogonal design has a relatively high ratio of time diversity. In addition, the proposed scheme has the following characteristics: (1) full spatial diversity (2) low rate (3) linear processing. We compare the proposed scheme with another complex design to show the tradeoffs. The proposed scheme can be of use for certain applications such as sensor networks and deep space exploration where there might be an imposed limit on the peak transmit power.     

Humidity's influence on visible region refractive index structure parameter C(n)(2)

In the near-infrared and visible bandpasses optical propagation theory conventionally assumes that humidity does not contribute to the effects of atmospheric turbulence on optical beams. While this assumption may be reasonable for dry locations, we demonstrate that there is an unequivocal effect owing to the presence of humidity upon the strength of turbulence parameter, C(n)(2), from data collected in the Chesapeake Bay area over 100 m length horizontal propagation paths. We describe and apply a novel technique, Hilbert phase analysis, to the relative humidity, temperature, and C(n)(2) data to show the contribution of the relevant climate variable to C(n)(2) as a function of time.     

Short communication: in vivo evaluation of microemulsion system for oral and parenteral delivery of rutaecarpine to rats

Rutaecarpine-loaded microemulsion composed of 10.8% polyethylene glycol 400, 7.2% Tween 80, 20% caster oil, and 62% water were previously reported to be physically and chemically stable for at least 6 months. For the development of a Rutaecarpine-loaded microemulsion, here we studied the pharmacokinetic profiles of rutaecarpine after oral and intravenous administration of rutaecarpine-loaded microemulsion compared to suspension. The AUC of rutaecarpine from microemulsion after oral and intravenous administration increased about three-fold compared with that from suspension. Furthermore, the rutaecarpine-loaded microemulsion gave significantly higher AUC and Cmax than did suspension, suggesting that the oral bioavailability of rutaecarpine in this microemulsion system could be enhanced due to the enhanced solubility of rutaecarpine by microemulsion. Thus, our results indicated that the microemulsion system composed of castor oil, polyethylene glycol 400, Tween 80, and water could be a more effective oral and parenteral dosage form for rutaecarpine.     

Mercuric ion sensing by a film bulk acoustic resonator

This paper describes a film bulk acoustic resonator (FBAR) mass sensor for detecting Hg2+ ion in water with excellent sensitivity and selectivity. When a thin Au film was deposited on the surface of an FBAR, the resonant frequency shifted to a lower value when the film was exposed to Hg2+ in aqueous solution. The FBAR sensor detected as low as 10(-9) M Hg2+ (0.2 ppb Hg2+) in water. Other ions such as K+, Ca2+, Mg2+, Zn2+, and Ni2+ had little or no effect on the resonant frequency of the FBAR. Coating of the FBAR Au surface with a self-assembled monolayer (SAM) of 4-mercaptobenzoic acid decreased the Hg2+ response.     

Ultra temperature-stable bulk-acoustic-wave resonators with SiO2 compensation layer

This paper describes temperature compensated bulk acoustic-wave resonators (BAR) with temperature coefficient of frequency (TCF) less than 1 ppm/degrees C at above 3 GHz. The temperature compensation is produced from the unique physical property of silicon dioxide's positive TCF, unlike most other materials that have negative TCF. Two types of resonators have been explored: film bulk acoustic resonator (FBAR) composed of Al/ZnO/Al/SiO2 on a surface micromachined cantilever that is released by XeF2 vapor etching and high-overtone acoustic resonator (HBAR) composed of an Al/ZnO/Al resonator on a bulk micromachined SiO2/Si/SiO2 supporting substrate.     

Water-repellent coating: formation of polymeric self-assembled monolayers on nanostructured surfaces

In this paper, we suggest a facile and effective method for water-repellent coating of oxide surfaces. As a coating material, we synthesized a new random copolymer, referred to as poly(TMSMA-r-fluoroMA), by the radical polymerization of 3-(trimethoxysilyl)propyl methacrylate (TMSMA) and a fluoromonomer(?) bearing methacrylate moiety (fluoroMA). The random copolymer was designed to consist of a 'surface-reactive part' (trimethoxysilyl group) for anchoring onto oxide-based surfaces and a 'functional part' (perfluoro group) for water repellency. The polymeric self-assembled monolayers (pSAMs) of poly(TMSMA-r-fluoroMA) were constructed on three different aluminum oxide substrates, such as flat, concave-textured, and nanoporous plates, and the static water contact angle of each surface before and after the formation of pSAMs was measured. The formation of pSAMs resulted in significantly enhanced hydrophobicity compared with the corresponding bare surfaces. In particular, among three poly(TMSMA-r-fluoroMA)-coated surfaces, the nanoporous plate showed the highest water-repellent property, with a static contact angle of ～163°, which is indicative of superhydrophobic surfaces.