Effect of Wind barrier on Wind Environment above Parallel Girders

This paper was reviewed and accepted by the APCWE-IX Programme Committee for Presentation at the 9th Asia-Pacific Conference on Wind Engineering, University of Auckland, Auckland, New Zealand, held from 3-7 December 2017

Aspartic Acid-Promoted Highly Selective and Sensitive Colorimetric Sensing of Cysteine in Rat Brain

Direct selective determination of cysteine in the cerebral system is of great importance because of the crucial roles of cysteine in physiological and pathological processes. In this study, we report a sensitive and selective colorimetric assay for cysteine in the rat brain with gold nanoparticles (Au-NPs) as the signal readout. Initially, Au-NPs synthesized with citrate as the stabilizer are red in color and exhibit absorption at 520 nm. The addition of an aqueous solution (20 μL) of cysteine or aspartic acid alone to a 200 μL Au-NP dispersion causes no aggregation, while the addition of an aqueous solution of cysteine into a Au-NP dispersion containing aspartic acid (1.8 mM) causes the aggregation of Au-NPs and thus results in the color change of the colloid from wine red to blue. These changes are ascribed to the ion pair interaction between aspartic acid and cysteine on the interface between Au-NPs and solution. The concentration of cysteine can be visualized with the naked eye and determined by UV–vis spectroscopy. The signal output shows a linear relationship for cysteine within the concentration range from 0.166 to 1.67 μM with a detection limit of 100 nM. The assay demonstrated here is highly selective and is free from the interference of other natural amino acids and other thiol-containing species as well as the species commonly existing in the brain such as lactate, ascorbic acid, and glucose. The basal dialysate level of cysteine in the microdialysate from the striatum of adult male Sprague–Dawley rats is determined to be around 9.6 ± 2.1 μM. The method demonstrated here is facile but reliable and durable and is envisaged to be applicable to understanding the chemical essence involved in physiological and pathological events associated with cysteine

Strong Interaction between Imidazolium-Based Polycationic Polymer and Ferricyanide: Toward Redox Potential Regulation for Selective In Vivo Electrochemical Measurements

This study effectively demonstrates a strategy to enable the ferricyanide-based second-generation biosensors for selective in vivo measurements of neurochemicals, with glucose as an example. The strategy is based on regulation of redox potential of ferricyanide mediator by carefully controlling the different adsorption ability of ferricyanide (Fe­(CN)₆^3‑) and ferrocyanide (Fe­(CN)₆^4‑) onto electrode surface. To realize the negative shift of the redox potential of Fe­(CN)₆^3‑/4‑, imidazolium-based polymer (Pim) is synthesized and used as a matrix for surface adsorption of Fe­(CN)₆^3‑/4‑ due to its stronger interaction with Fe­(CN)₆^3‑ than with Fe­(CN)₆^4‑. The different adsorption ability of Fe­(CN)₆^3‑ and Fe­(CN)₆^4‑ onto electrodes modified with a composite of Pim and multiwalled carbon nanotubes (MWNTs) eventually enables the stable surface adsorption of both species to generate integrated biosensors and, more importantly, leads to a negative shift of the redox potential of the surface-confined redox mediator. Using glucose oxidase (GOD) as the model biorecognition units, we demonstrate the validity of the ferricyanide-based second-generation biosensors for selective in vivo neurochemical measurements. We find that the biosensors developed with the strategy demonstrated in this study can be used well as the selective detector for continuous online detection of striatum glucose of guinea pigs, by integration with in vivo microdialysis. This study essentially paves a new avenue to developing electrochemical biosensors effectively for in vivo neurochemical measurements, which is envisaged to be of great importance in understanding the molecular basis of physiological and pathological events

Shape-Controlled Fabrication of the Polymer-Based Micromotor Based on the Polydimethylsiloxane Template

We report the utilization of the polydimethylsiloxane template to construct polymer-based autonomous micromotors with various structures. Solid or hollow micromotors, which consist of polycaprolactone and platinum nanoparticles, can be obtained with controllable sizes and shapes. The resulting micromotor can not only be self-propelled in solution based on the bubble propulsion mechanism in the presence of the hydrogen peroxide fuel, but also exhibit structure-dependent motion behavior. In addition, the micromotors can exhibit various functions, ranging from fluorescence, magnetic control to cargo transportation. Since the current method can be extended to a variety of organic and inorganic materials, we thus believe it may have great potential in the fabrication of different functional micromotors for diverse applications