Functional Human Vascular Network Generated in Photocrosslinkable Gelatin Methacrylate Hydrogels

The generation of functional, 3D vascular networks is a fundamental prerequisite for the development of many future tissue engineering-based therapies. Current approaches in vascular network bioengineering are largely carried out using natural hydrogels as embedding scaffolds. However, most natural hydrogels present a poor mechanical stability and a suboptimal durability, which are critical limitations that hamper their widespread applicability. The search for improved hydrogels has become a priority in tissue engineering research. Here, the suitability of a photopolymerizable gelatin methacrylate (GelMA) hydrogel to support human progenitor cell-based formation of vascular networks is demonstrated. Using GelMA as the embedding scaffold, it is shown that 3D constructs containing human blood-derived endothelial colony-forming cells (ECFCs) and bone marrow-derived mesenchymal stem cells (MSCs) generate extensive capillary-like networks in vitro. These vascular structures contain distinct lumens that are formed by the fusion of ECFC intracellular vacuoles in a process of vascular morphogenesis. The process of vascular network formation is dependent on the presence of MSCs, which differentiate into perivascular cells occupying abluminal positions within the network. Importantly, it is shown that implantation of cell-laden GelMA hydrogels into immunodeficient mice results in a rapid formation of functional anastomoses between the bioengineered human vascular network and the mouse vasculature. Furthermore, it is shown that the degree of methacrylation of the GelMA can be used to modulate the cellular behavior and the extent of vascular network formation both in vitro and in vivo. These data suggest that GelMA hydrogels can be used for biomedical applications that require the formation of microvascular networks, including the development of complex engineered tissues.     

Heat Dissipation of Transparent Graphene Defoggers

In spite of recent successful demonstrations of flexible and transparent graphene heaters, the underlying heat‐transfer mechanism is not understood due to the complexity of the heating system. Here, graphene/glass defoggers are fabricated and the dynamic response of the temperature as a function of input electrical power is measured. The graphene/glass defoggers reveal shorter response times than Cr/glass defoggers. Furthermore, the saturated temperature of the graphene/glass defoggers is higher than for Cr/glass defoggers at a given input electrical power. The observed dynamic response to temperature is well‐fitted to the power‐balance model. The response time of graphene/glass defogger is shorter by 44% than that of the Cr/glass defogger. The convective heat‐transfer coefficient of graphene is 12.4 × 10^?4 W cm^?2 °C^?1, similar to that of glass (11.1 × 10^?4 W cm^?2 °C^?1) but smaller than that of chromium (17.1 × 10^?4 W cm^?2 °C^?1). The graphene‐based system reveals the lowest convective heat‐transfer coefficient due to its ideal flat surface compared to its counterparts of carbon nanotubes (CNTs) and reduced graphene oxide (RGO)‐based systems.     

Expression and localization of translationally controlled tumor protein in rat urinary organs

This study describes the very first assessment of the expression and localization of translationally controlled tumor protein (TCTP) in adult rat urinary organs. TCTP expression levels in kidneys, urinary bladder, and urethra were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE) and Western blotting, and its cellular localization was examined immunohistochemically in paraffin sections of various urinary organs. TCTP was found in all urinary organs. Its expression was high in the urethra and low in the bladder. TCTP was localized in glomerular podocytes, epithelium of proximal and distal renal tubules, in the loop of Henle, and in the transitional epithelium of the bladder and urethra, mostly in basal cell layers). The subcellular localization of TCTP in these urinary organs was cytoplasmic. These findings suggest that TCTP may be involved in urine formation and excretion. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Effect of non-uniform void size and shape distributions on deformation failure in cast aluminum alloy

Tensile tests were conducted on several cast aluminum specimens with different degrees of porosity. The effects of non-uniform void size and shape distributions, including spherical and non-spherical types, on stress-strain behavior resulting from different initiation mechanisms were investigated. A micro-mechanics-based statistical approach was employed, and the heterogeneous microstructures could therefore be modeled during the deformation process. The predicted changes of the distributions of void size and void shape generally agreed with experimental results. Void spatial variation was also quantified, and its effects on the level of failure were analyzed. The void spatial variation facilitated development of inhomogeneous deformation, which results in failure.     

Bending fatigue characteristics of wire rope

Wire rope in elevators can become disconnected by tensile stress from friction between the rope and sheave, and by repeated stress including bending stress from various effects formed during contact between the rope and sheave. It is known that in designing wire rope, its strength is affected when wire disconnection occurs. However, insufficient related data is available. Therefore, fracture strength reduction and the effect of bending fatigue on wire rope life is difficult to evaluate. We considered the effects of wire rope diameter and tensile stress on fracture strength and wire rope life. We observed that fracture strength rapidly decreased when bending fatigue accumulated at the same time that the wire became disconnected. Moreover, bending fatigue was shown to be a crucial factor in decreased wire rope life.     

Cloud computing paradigms for pleasingly parallel biomedical applications

Cloud computing offers exciting new approaches for scientific computing that leverage major commercial players’ hardware and software investments in large‐scale data centers. Loosely coupled problems are very important in many scientific fields, and with the ongoing move towards data‐intensive computing, they are on the rise. There exist several different approaches to leveraging clouds and cloud‐oriented data processing frameworks to perform pleasingly parallel (also called embarrassingly parallel) computations. In this paper, we present three pleasingly parallel biomedical applications: (i) assembly of genome fragments; (ii) sequence alignment and similarity search; and (iii) dimension reduction in the analysis of chemical structures, which are implemented utilizing a cloud infrastructure service‐based utility computing models of Amazon Web Services ( http://Amazon.com Inc., Seattle, WA, USA) and Microsoft Windows Azure (Microsoft Corp., Redmond, WA, USA) as well as utilizing MapReduce‐based data processing frameworks Apache Hadoop (Apache Software Foundation, Los Angeles, CA, USA) and Microsoft DryadLINQ. We review and compare each of these frameworks, performing a comparative study among them based on performance, cost, and usability. High latency, eventually consistent cloud infrastructure service‐based frameworks that rely on off‐the‐node cloud storage were able to exhibit performance efficiencies and scalability comparable to the MapReduce‐based frameworks with local disk‐based storage for the applications considered. In this paper, we also analyze variations in cost among the different platform choices (e.g., Elastic Compute Cloud instance types), highlighting the importance of selecting an appropriate platform based on the nature of the computation. Copyright © 2011 John Wiley & Sons, Ltd.     

Nanotribological Properties of Fluorinated, Hydrogenated, and Oxidized Graphenes

Recently, the tribological properties of graphene have been intensively examined for potential applications in micro- and nano-mechanical graphene-based devices. Here, we report that the tribological properties can be easily altered via simple chemical modifications of the graphene surface. Friction force microscopy measurements show that hydrogenated, fluorinated, and oxidized graphenes exhibit, 2-, 6-, and 7-fold enhanced nanoscale friction on their surfaces, respectively, compared to pristine graphene. The measured nanoscale friction should be associated with the adhesive and elastic properties of the chemically modified graphenes. Density-functional theory calculations suggest that, while the adhesive properties of chemically modified graphenes are marginally reduced down to ~30 %, the out-of-plane elastic properties are drastically increased up to 800 %. Based on these findings, we propose that nanoscale friction on graphene surfaces is characteristically different from that on conventional solid surfaces; stiffer graphene exhibits higher friction, whereas a stiffer three-dimensional solid generally exhibits lower friction. The unusual friction mechanics of graphene is attributed to the intrinsic mechanical anisotropy of graphene, which is inherently stiff in plane, but remarkably flexible out of plane. The out-of-plane flexibility can be modulated up to an order of magnitude by chemical treatment of the graphene surface. The correlation between the measured nanoscale friction and the calculated out-of-plane flexibility suggests that the frictional energy in graphene is mainly dissipated through the out-of-plane vibrations, or the flexural phonons of graphene.     

Improvements of Mixed-surfactants in Alkaline/Surfactant/Polymer Solutions

The authors present a comprehensive evaluation of phase behaviors of alkaline/surfactant/polymer (ASP) systems. The experimental results proved that the phase behavior of mixed-surfactant solutions (single- and double-tail anionic surfactants) would be better than the one of single surfactant. These mixtures were also more compatible with polymer, and adjusted optimum salinity to the reservoir brine. They next examined the role of alkalis in ASP process. Three types of alkalis were tested to select the optimum one for high-temperature reservoir. This study showed that sodium metaborate is the best choice.     

Dimeric beta-cyclodextrin-based supramolecular ligands and their copper(II) complexes as metalloenzyme models

New supramolecular ligands possessing linear 13- and 15-membered pyridine diamidetriamine chelators between the primary sides of two beta-cyclodextrin cavities were synthesized, and characterized by MALDI-MS, NMR, IR and UV-Visible spectroscopy. Fluorescence and pH-metric titration were carried out in order to ascertain their behavior as bifunctional hosts for fluorescent guests and Cu(II) ion. The pKa value for the Cu(II) promoted deprotonation of amide ligands was determined to be 6.2 from pH-absorbance profile. Above pH 8.0, two deprotonated amides and three amino groups chelated Cu(II) ion, and yielded penta-coordinated Cu(II) complexes. The Cu(II) complexes catalyzed the hydrolysis of p-nitrophenyl acetate, adamantate and amino acids. Especially, the complex containing 13-membered chelator is an artificial metalloesterase with catalytic rate constant kcat = 3.8 x 10(-3) min-1 and Michaelis constant K(m) = 3.5 x 10(-4) M for the hydrolysis of p-nitrophenyl adamantate via metal-hydroxide mechanism.     

Effect of Lentinus edodes β-Glucan-Enriched Materials on the Textural, Rheological, and Oil-Resisting Properties of Instant Fried Noodles

With the recent well-being trend, a great deal of effort has been made to develop instant fried noodles with beneficial health effects. Thus, β-glucan-enriched materials (BGEMs) were obtained from Lentinus edodes mushroom and their effects on the quality attributes of instant fried noodles were characterized in terms of rheological, textural, and oil-resisting properties. When BGEMs were mixed with wheat flour, different thermomechanical profiles were observed by a Mixolab, enhancing dough stability and water absorption. The use of BGEMs raised the viscoelastic properties of noodle dough with a great increase in the elastic property. In addition, the dough samples prepared with more BGEMs exhibited greater elongational viscosity. In the case of fried noodle strands, the incorporation of BGEMs led to a significant increase in the breaking stress and produced a surface microstructure with smaller voids. Moreover, the oil uptake of fried noodles containing BGEMs was significantly reduced by 22%. Therefore, it showed that BGEMs had positive impacts on the quality attributes of instant fried noodles and could also be used as an oil barrier to produce fried noodles with a reduced content of oil and calories.