The potential of sphingomyelin as a chemopreventive agent in AOM-induced colon cancer model: wild-type and p53+/- mice

A protective effect of sphingolipids on colorectal cancer (CRC) has been reported in certain mouse strains. It is unknown if sphingolipids are protective in a p53 deficiency mouse model of CRC. This study investigated the effect of sphingomyelin (SM) on intestinal sphingomyelinase (SMase) activity, colonic epithelial biology and azoxymethane (AOM)-induced CRC. Groups of wild-type (C57BL/6J) and p53+/- mice were fed 0.1% SM diet for 4 wk, administered a single AOM injection and then killed 6 h later to measure apoptosis and proliferation. Separately, both mouse types were fed 0.05% SM diet, administered three AOM injections and killed 33-38 wk later to measure tumour formation. SM significantly increased SMase activity and reduced proliferation (p < 0.05) in wild-type and p53+/- mice. SM did not regulate baseline apoptosis, apoptotic response to AOM or apoptosis in tumours, nor did it restore defective apoptosis in p53+/- mice. There was a nonsignificant trend to reduced tumour incidence with SM in wild-type (p = 0.15) and p53+/- (p = 0.12) mice. In conclusion, while increasing intestinal SMase activity and suppressing proliferation, SM did not promote any form of apoptosis and failed to achieve significant protection in these mice. Further investigation to understand the variable effect of SM in preventing CRC is warranted.     

Reversal of the Inflammatory Responses in Fabry Patient iPSC-Derived Cardiovascular Endothelial Cells by CRISPR/Cas9-Corrected Mutation

The late-onset type of Fabry disease (FD) with GLA IVS4 + 919G > A mutation has been shown to lead to cardiovascular dysfunctions. In order to eliminate variations in other aspects of the genetic background, we established the isogenic control of induced pluripotent stem cells (iPSCs) for the identification of the pathogenetic factors for FD phenotypes through CRISPR/Cas9 genomic editing. We adopted droplet digital PCR (ddPCR) to efficiently capture mutational events, thus enabling isolation of the corrected FD from FD-iPSCs. Both of these exhibited the characteristics of pluripotency and phenotypic plasticity, and they can be differentiated into endothelial cells (ECs). We demonstrated the phenotypic abnormalities in FD iPSC-derived ECs (FD-ECs), including intracellular Gb3 accumulation, autophagic flux impairment, and reactive oxygen species (ROS) production, and these abnormalities were rescued in isogenic control iPSC-derived ECs (corrected FD-ECs). Microarray profiling revealed that corrected FD-derived endothelial cells reversed the enrichment of genes in the pro-inflammatory pathway and validated the downregulation of NF-κB and the MAPK signaling pathway. Our findings highlighted the critical role of ECs in FD-associated vascular dysfunctions by establishing a reliable isogenic control and providing information on potential cellular targets to reduce the morbidity and mortality of FD patients with vascular complications.     

Characterization of zirconia specimens fabricated by ceramic on-demand extrusion

The Ceramic On-Demand Extrusion (CODE) process is a novel additive manufacturing method for fabricating dense (~99% of theoretical density) ceramic components from aqueous, high solids loading pastes (>50?vol%). In this study, 3?mol% Y₂O₃ stabilized zirconia (3YSZ) specimens were fabricated using the CODE process. The specimens were then dried in a humidity-controlled environmental chamber and afterwards sintered under atmospheric conditions. Mechanical properties of the sintered specimens were examined using ASTM standard test techniques, including density, Young’s modulus, flexural strength, Weibull modulus, fracture toughness, and Vickers hardness. The microstructure was analyzed and grain size measured using scanning electron microscopy. The results were compared with those from Direct Inkjet Printing, Selective Laser Sintering, Lithography-based Ceramic Manufacturing (LCM), and other extrusion-based processes, and indicated that zirconia specimens produced by CODE exhibit superior mechanical properties among the additive manufacturing processes. Several sample components were produced to demonstrate CODE’s capability for fabricating geometrically complex ceramic components. The surface roughness of these components was also examined.     

Synthesis and characterization of copolyimides with high solubility

A series of copolyimides were prepared from various diamines (polysiloxane and isophorone units) with aromatic tetracarboxylic dianhydrides via a two‐step (thermal imidization) method. The monomers and polymers were produced in high yields, and the copolyimides containing Si? O? C bonds and asymmetric meta catenation in the polymer backbone exhibited good solubility. The glass‐transition temperatures (T_g's) of all the copolyimides were found to be 201–262 and 215–258°C by differential scanning calorimetry (DSC) and dynamic mechanical analysis, respectively. Thermogravimetric analyses indicated that the polymers were fairly stable up to 502–578°C (10 wt % loss in N2) and 490–574°C (10 wt % loss in air). The char yields at 800°C in N2 and air atmospheres were 26–59 and 20–53%, respectively. The copolymerization results, determined with 1H‐NMR and DSC, indicated a random copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1963–1970, 2003     

Ag+ contained complex membrane for the separation of C4 olefin/paraffin mixture

The C₄ olefin/paraffin mixture was separated by means of the PE modified reversible complexing membrane, polyethylene-g-acrylic acid-Ag₊(PE-g-AA-Ag₊). The olefin could be transported to the other side of the membrane by silver facilitating phenomenon owing to the formation of (Ag-olefin)₊ complex. The SEM-EDX spectrum showed a homogeneous silver ion distribution across the dense complex membrane's cross-section at higher than about 60% grafting. The gas permeation properties measured by a gas chromatographic method implied a silver ions facilitating effect towards olefin. At 30°C and 111.7% grafting, the complex membrane exhibited a trans-2-butene/isobutane selectivity of 12.5 and a cis-2-butene/isobutane selectivity of 9.2. The permeation activation energy of the C₄ olefins became lower than that of C₄ paraffin as a result of the silver ions facilitated effect. The cis-2-butene has a significant higher complex equilibrium constant than that of the trans-2-butene in complexing with the complex membrane.     

Reinforcement of dynamically vulcanized EPDM/PP elastomers using organoclay fillers

Dynamically vulcanized EPDM/PP (ethylene-propylene-diene/polypropylene) elastomers reinforced with various amounts of organoclay were prepared using octylphenol-formaldehyde resin and stannous chloride dehydrate as vulcanizing agents. The effects of organoclay on vulcanization characteristics, rheological behavior, morphology, thermal stability and thermomechanical properties were studied. Experimental results showed that organoclay affected neither the vulcanization process nor the degree of vulcanization chemically. X-ray analysis revealed that these organoclay-filled thermoplastic vulcanizates (TPVs) were intercalated. With respect to the mechanical properties, organoclay increased both the strength and degree of elongation of TPVs. The morphological observation of fractured surfaces suggested that organoclay acted as a nucleating agent in TPVs, improving their mechanical properties. However, adding organoclay reduced the thermal stability of TPVs by decomposing the swelling agents in the organoclay.     

高频细筛在龙桥矿业磁选二段分级中的应用

龙桥矿业为解决旋流器在2段磨矿分级中存在的分级效率低导致有用矿物过磨、磨矿循环负荷过大增加磨矿能耗等问题,引进了德瑞克5层重叠式高频振动筛替代旋流器分级,通过高频振动筛的使用,将分级效率由30%提高到85%以上,磨矿循环负荷由300%～350%降低为50%左右。在生产实践中实现了减少了1台2段磨机的使用,改造后年可节约生产成本139万元,经济效益显著。     

Resource brokering using a multi‐site resource allocation strategy for computational grids

Grid computing employs heterogeneous resources which may be installed on different platforms, hardware/software, computer architectures, and perhaps using different computer languages to solve large‐scale computational problems. As many more Grids are being developed worldwide, the number of multi‐institutional collaborations is growing rapidly. However, to realize Grid computing's full potential, it is expected that Grid participants must be able to share one another's resources. This paper presents a resource broker that employs the multi‐site resource allocation (MSRA) strategy and the dynamic domain‐based network information model that we propose to allocate Grid resources to submitted jobs, where the Grid resources may be dispersed at different sites, and owned and governed by different organizations or institutes. The jobs and resources may also belong to different clusters/sites. Resource statuses collected by the Ganglia, and network bandwidths gathered by the Network Weather Service, are both considered in the proposed scheduling approach. A dynamic domain‐based model for network information measurement is also proposed to choose the most appropriate resources that meet the jobs' execution requirements. Experimental results show that MSRA outperformed the other tested strategies. Copyright © 2010 John Wiley & Sons, Ltd.     

Optimal design of parallel channel patterns in a micro methanol steam reformer

This study describes the performance of micro methanol steam reformers with channel widths optimized using the simplified conjugate gradient method (SCGM), which uses a minimum objective function of the H₂ mass fraction standard deviation in channels. A three-dimensional numerical model and optimal simplified conjugate gradient algorithm were built to predict and search for the effects of channel widths and flow rate on the performance of chemical reactions. Furthermore, this simulation model was compared to; and corresponded well with existing experimental data. Distributions of velocity, temperature, and gas concentrations (CH₃OH, CO, H₂, and CO₂) were predicted, and the methanol conversion ratio was also evaluated. The mole fraction of CO contained in the reformed gas, which is essential to preventing poisoning of the catalyst layers of fuel cells, is also investigated. In the optimization search process, the governing equations use the continuity, momentum, heat transfer, and species equations to evaluate the performance of the steam reformer. The results show that channel width optimization can not only increase the methanol conversion ratio and hydrogen production rate but also decrease the concentration of carbon monoxide. The velocity and mixture gas density distributions in channels are discussed and plotted at various locations for an inlet liquid flow rate of 0.3 cc min⁻¹. Full development is not obtained in the downstream channel flow, the velocity in channel is increased from 1.28 m s⁻¹ to 2.36 m s⁻¹ at location Y = 1 mm–32 mm, respectively. This can be attributed to a continuous increase in the lightweight H₂ species as a result of chemical reactions in the channels.