ALBERT

Description: This article is a brief summary of my plenary talk at the World Biomaterials Congress in Chengdu, Sichuan, China, June 1–5, 2012. It highlights the trend to design and develop biomaterial implants and devices that are more compact and more efficient, as they “shrink” from the macro- to the micro- and down to the nano-scale.

Description: To develop a new composite adsorbent with high performance, fir sawdust and CaCl 2 are selected as raw materials. The mass transfer is enhanced by carbonizing and activating the sawdust and heat transfer is enhanced by adding expanded graphite into the adsorbent. The effect of the preparation temperature and the expanded graphite content on the adsorption performance is investigated. The results show that the new adsorbent exhibits a high adsorption performance due to its high porosity, uniform distribution and high content of CaCl 2 and high thermal conductivity. Also, the experimental results indicate that the rate of ammonia adsorption on the adsorbent depends on the expanded graphite content and the carbonization and activation temperature. The adsorbent prepared at 500°C and with the expanded graphite content of 30% has the best performance in terms of the adsorption refrigeration, which adsorbs ammonia as high as 0.37 g g −1 at 10 min.

Description: Highly c -axis-oriented GaN films were deposited on Ti coated glass substrates using low temperature electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition system (ECR-PEMOCVD) with trimethyl gallium (TMGa) as gallium source. The influence of TMGa flux on the properties of GaN films were systematically investigated by reflection high energy electron diffraction (RHEED), X-ray diffraction analysis (XRD), atomic force microscopy (AFM) and Raman scattering. The GaN film with small surface roughness and high c -axis preferred orientation was successfully achieved at the optimized TMGa flux of 1.0 sccm. The ohmic contact characteristic between GaN and Ti layer was clearly demonstrated by the near-linear current-voltage ( I–V ) curve. The GaN/Ti/glass structure has great potential to dramatically improve the scalability and reduce the cost of solid-state lighting light emitting diodes.

Description: The effect of microstructure and surface chemistry on nicotine adsorption capacity of almond-shell-based activated carbon was studied. Almond-shell-based activated carbon was reactivated or modified with steam, ZnCl 2 and NaHSO 4 separately. The surface area and pore structure parameters of activated carbon were determined from the adsorption-desorption isotherm of nitrogen at 77 K. Boehm titration and FTIR were explored to determine the surface oxygen groups. The results revealed that nicotine adsorption from solution on carbons depend on the micropores and phenolic groups. A strong correlation between the amounts of adsorbed nicotine and the phenolic groups was observed, whereas the higher amounts of carboxylic groups decrease the nicotine adsorption capacity on activated carbons.

Description: The 12 May 2008 M s 8.0 Wenchuan earthquake caused notable changes in the water levels of wells in the Three Gorges area. This work examines the relationship between these co-seismic changes in water level and the changes in aquifer parameters. Three wells in the area with good responses to earth tide were chosen for analysis. Water-level data from February to June 2008 were used to calculate the aquifer transmissivity, permeability and specific storage of the rocks, and analyze the relationship between the co-seismic responses of the wells and their aquifer parameters. The results show that the Wenchuan earthquake changed these parameters considerably, thereby controlling co- and post-seismic variations of water level. The values of these parameters prior to the earthquake are linearly related with the amplitudes of co-seismic variations in water level. The larger the aquifer transmissivity, the more remarkable the co-seismic change in water level. During the earthquake, changes in aquifer parameters were found to be associated with co-seismic variations in water level, with the larger changes occurring when the co-seismic variation in water level was larger. The tectonic setting has a certain degree of influence on the co- and post-seismic changes in water level. The permeability structures of the fault zone appear to determine the manner of co-seismic variation in water level. Moreover, it seems that the water level in wells where groundwater converges more easily can recover faster following an earthquake. Insight from this study helps to improve understanding of the characteristics of water-level changes caused by earthquakes.

Description: The P2X 7 receptor (P2X 7 R) is an important member of the P2X family of ligand-gated ion channels that respond to ATP as the endogenous agonist. Studies suggest that P2X 7 R plays a potentially pivotal role in a variety of physiological functions, including peripheral and central neuronal transmission, smooth muscle contraction, and inflammation. Thus, P2X 7 R may be a potential target for drug development. Here, we used a FlexStation to examine the function of recombinant P2X 7 R stably expressed in human embryonic kidney 293 cells and to compare three high-throughput screening assays: a membrane potential assay, an ethidium bromide uptake assay, and a calcium influx assay. We found that all three assays were suitable for the analysis of P2X 7 R, but the calcium influx assay was the most robust and is the best choice as a first high-throughput screening assay when embarking on a P2X 7 R drug discovery project.

Description: The wettability of boron nitride nanotube (BNNT) films was modified using a combination of pulsed and continuous wave (CW) mode plasma. The combined mode effectively modified the wettability of BNNT films and kept the nanostructures intact. The BNNT films changed from superhydrophobic to superhydrophilic after combined mode treatment at 600 W min. In contrast, the contact angle controllable decreased linearly in a controllable way with increasing energy input before eventually becoming superhydrophilic after 1000 W min of CW mode treatment. A high concentration of graft functional groups formed, along with point defects. More point defects formed when using combined modes and higher energy input. Mainly amine functional groups were grafted by combined mode plasma, while the CW mode plasma led to more formation of amide and imine on the BNNTs. Research into controllable wettability and selection of grafted functional groups should enable promising applications of BNNTs in composites and biology in the future.

Description: Controllable synthesis of uniform and single-crystalline CdMoO 4 nano-octahedra has been successfully realized at large-scale by a facile reverse-microemulsion route at room temperature. The structures, compositions and morphologies of the as-prepared products were characterized in detail by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), respectively. According to the thermochemical cycle, the relationship between the standard molar enthalpy of formation of nano-CdMoO 4 and bulk CdMoO 4 was proposed for the first time. In combination with micro-calorimetry, the standard molar enthalpies of formation at 298.15 K of as-ynthesized CdMoO 4 nano-octahedra were obtained.

Description: Endothelial cell therapy has been implicated to enhance tissue regeneration and vascularization in ischemic kidney. However, no published study has yet examined direct effects of endothelial cell treatment in kidney recovery. This study investigated the therapeutic efficacy of endothelial cells in a mouse model with acute kidney injury (AKI). Thus, human embryonic stem cells-derived endothelial cells (hESC-ECs) labeled with a reporter system encoding a double fusion reporter gene for firefly luciferase (Fluc) and green fluorescent protein (GFP) were characterized by Fluc imaging and immunofluoresence staining. Cultured hESC-ECs (1×10 6 ) were injected into ischemic kidney shortly after AKI. Survival of the transplanted hESC-ECs was monitored in vivo from day 1 to 14 after endothelial cell transplantation and potential impact of hESC-EC treatment on renal regeneration was assessed by histological analyses. We report that a substantial level of bioluminescence activity was detected 24 h after hESC-EC injection followed by a gradual decline from 1 to 14 d. Human ESC-ECs markedly accelerated kidney cell proliferation in response to ischaemia-induced damage, indicated by an elevated number of BrdU + cells. Co-expression of Sca-1, a kidney stem cell proliferation marker, and BrdU further suggested that the observed stimulation in renal cell regeneration was, at least in part, due to increased proliferation of renal resident stem cells especially within the medullary cords and arteriole. Differentiation of hESC-ECs to smooth muscle cells was also observed at an early stage of kidney recovery. In summary, our results suggest that endothelial cell therapy facilitates kidney recovery by promoting vascularization, trans-differentiation and endogenous renal stem cell proliferation in AKI.

Description: For about three decades, DNA-based nanotechnology has been undergoing development as an assembly method for nanostructured materials. The DNA origami method pioneered by Rothemund paved the way for the formation of 3D structures using DNA self assembly. The origami approach uses a long scaffold strand as the input for the self assembly of a few hundred staple strands into desired shapes. Herein, we present a 3D origami “roller” (75 nm in length) designed using caDNAno software. This has the potential to be used as a template to assemble nanoparticles into different pre-defined shapes. The “roller” was characterized with agarose gel electrophoresis, atomic force microscopy (AFM) and transmission electron microscopy (TEM).