Aerosol Particle Collection Efficiency of Holey Carbon Film-Coated TEM Grids

A simple sampling method to collect aerosol particles for transmission electron microscope (TEM) analysis was developed by R’mili and others in 2013. The method involves passing air through a holey carbon film-coated copper mesh TEM grid (holey carbon grid) and sampling particles by filtration. In this study, we proposed a modified calculation method to represent the collection efficiencies of holey carbon grids, taking into consideration the porosity of the copper mesh. We then evaluated the particle collection efficiencies of holey carbon grids both theoretically and experimentally. We tested the collection efficiency of two types of holey carbon grids, with nominal pore sizes of 1.2 and 0.6 μm, using particles of monodispersed polystyrene latex (PSL) and potassium chloride. The overall collection efficiency of each grid (E_grid) was determined by the downstream/upstream concentration ratio measured by condensation particle counters (CPCs). In addition, for PSL particles, the collection efficiency of the holey carbon film (E_film) was determined by the ratio of the number of particles on the film (counted on a scanning electron microscope) to the number of inflow particles (counted by a CPC). We compared model calculations against the experimental results obtained in this study and those reported by R’mili and others in 2013. These data showed that the calculated E_grid values were in reasonably good agreement with the experimental E_grid values. However, although the model calculation indicated that E_film ≈ E_grid, there was an inconsistency between the experimental E_film and E_grid, which requires further investigation in order to determine its cause.

Copyright 2014 American Association for Aerosol Research     

Condensation of organic binary mixtures flowing horizontally in a horizontal tube bundle

Both heat and mass transfer in the gas phase and heat transfer in the liquid phase are examined experimentally for film condensation of organic binary mixtures such as ethanol-water and methanol-water. Experimental results on the average heat flux, vapor-liquid interface temperature and liquid-phase Nusselt number are compared with analytical solutions based on stagnant film theory and heat-transfer relationships for film condensation from a pure vapor. Experimental heat transfer results agree well with the analytical solutions, except that the experimental liquid-phase Nusselt numbers under conditions of low mass fraction of water are considerably higher than predicted by the analytical solutions. This high value of the liquid-phase Nusselt number is considered to be caused by dropwise condensation in the liquid phase. However, its effect on the tube bundle is not so remarkable compared with that in gravity-controlled condensation on a vertical surface. This is considered to be caused by the condensate inundation effect. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(6): 342–361, 1996     

Serum Amyloid A3 Promoter-Driven Luciferase Activity Enables Visualization of Diabetic Kidney Disease

The early detection of diabetic nephropathy (DN) in mice is necessary for the development of drugs and functional foods. The purpose of this study was to identify genes that are significantly upregulated in the early stage of DN progression and develop a novel model to non-invasively monitor disease progression within living animals using in vivo imaging technology. Streptozotocin (STZ) treatment has been widely used as a DN model; however, it also exhibits direct cytotoxicity to the kidneys. As it is important to distinguish between DN-related and STZ-induced nephropathy, in this study, we compared renal responses induced by the diabetic milieu with two types of STZ models: multiple low-dose STZ injections with a high-fat diet and two moderate-dose STZ injections to induce DN. We found 221 genes whose expression was significantly altered during DN development in both models and identified serum amyloid A3 (Saa3) as a candidate gene. Next, we applied the Saa3 promoter-driven luciferase reporter (Saa3-promoter luc mice) to these two STZ models and performed in vivo bioluminescent imaging to monitor the progression of renal pathology. In this study, to further exclude the possibility that the in vivo bioluminescence signal is related to renal cytotoxicity by STZ treatment, we injected insulin into Saa3-promoter luc mice and showed that insulin treatment could downregulate renal inflammatory responses with a decreased signal intensity of in vivo bioluminescence imaging. These results strongly suggest that Saa3 promoter activity is a potent non-invasive indicator that can be used to monitor DN progression and explore therapeutic agents and functional foods.     

Immunomodulatory Properties and Osteogenic Activity of Polyetheretherketone Coated with Titanate Nanonetwork Structures

Polyetheretherketone (PEEK) is a potential substitute for conventional metallic biomedical implants owing to its superior mechanical and chemical properties, as well as biocompatibility. However, its inherent bio-inertness and poor osseointegration limit its use in clinical applications. Herein, thin titanium films were deposited on the PEEK substrate by plasma sputtering, and porous nanonetwork structures were incorporated on the PEEK surface by alkali treatment (PEEK-TNS). Changes in the physical and chemical characteristics of the PEEK surface were analyzed to establish the interactions with cell behaviors. The osteoimmunomodulatory properties were evaluated using macrophage cells and osteoblast lineage cells. The functionalized nanostructured surface of PEEK-TNS effectively promoted initial cell adhesion and proliferation, suppressed inflammatory responses, and induced macrophages to anti-inflammatory M2 polarization. Compared with PEEK, PEEK-TNS provided a more beneficial osteoimmune environment, including increased levels of osteogenic, angiogenic, and fibrogenic gene expression, and balanced osteoclast activities. Furthermore, the crosstalk between macrophages and osteoblast cells showed that PEEK-TNS could provide favorable osteoimmunodulatory environment for bone regeneration. PEEK-TNS exhibited high osteogenic activity, as indicated by alkaline phosphatase activity, osteogenic factor production, and the osteogenesis/osteoclastogenesis-related gene expression of osteoblasts. The study establishes that the fabrication of titanate nanonetwork structures on PEEK surfaces could extract an adequate immune response and favorable osteogenesis for functional bone regeneration. Furthermore, it indicates the potential of PEEK-TNS in implant applications.     

Effects of fatty acid and emulsifier on the complex formation and in vitro digestibility of gelatinized potato starch

The effects of fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with varying chain length in their acyl chains on the extent of complex formation (complex index) and in vitro enzymatic digestibility of gelatinized potato starch were investigated. The complex index increased with increase in the concentration of the ligands (fatty acid, monoacylglycerol, and polyglycerol fatty acid ester), with the plateau in the complex index value depending on the type of ligands. In comparison of complex index among fatty acid-samples, the complex index maximum increased as the chain length increased up to octanoic acid and then decreased. In comparison of complex index among fatty acid-, monoacylglycerol-, and polyglycerol fatty acid ester-samples at each acyl chain, the complex index maximum followed the order polyglycerol fatty acid ester > monoacylglycerol > fatty acid. Fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with long acyl chains greatly reduced the enzymatic hydrolysis of starch. Polyglycerol fatty acid ester with palmitic acid chains was the strongest inhibitor of starch hydrolysis, suggesting that further complex formation may occur during the hydrolysis of gelatinized starch (enzyme-annealing).     

Preparation of sharp-melting hard palm midfraction and its use as hard butter in chocolate

Preparation of hard palm midfractions (PMF) and its use as a cocoa butter equivalent ingredient were studied. Hard PMF is obtained by multistep fractionation of palm oil involving dry fractionation (DF) and/or solvent fractionation (SF), usually using hexane or acetone. From our experience, in acetone, a polar solvent, symmetrical 1,3-disaturated triacylglycerols tend to selectively crystallize more than nonsymmetrical 1,2- or 2,3-disaturated triacylglycerols, making it suitable for obtaining the solid midfraction. Unfortunately, triacylglycerols are very soluble in hexane, and temperatures at least 15 degrees lower than those required for acetone must be used for equivalent crystal yields. On the other hand, DF is a less expensive and safer process. Thus, multistep fractionation combining DF and SF using acetone was developed to achieve sufficient removal of high-melting components, and further enrichment of 1,3-dipalmitoyl-2-oleoylglycerol and the hard PMF was obtained by triple-step fractionation of palm olein or double-step fractionation of soft PMF. Compared to conventional hard PMF, this hard PMF had a steeper melting curve and better snapping and sharp-melting qualities when used in chocolate. Heat resistance of the hard PMF chocolate was similar to the conventional hard PMF chocolate, and its bloom resistance could be improved by adding polyglycerol fatty acid esters.     

Mycotoxicological quality evaluation of corn samples used by processing industries in the Northern region of Paraná State,Brazil

Based on fungal and fumonisin contamination of 870 freshly harvested samples, the quality of corn used by processing industries in the Northern region of Paraná State, Brazil (2003 and 2004 crop-year) was evaluated. Sampling was carried out for each crop at two points in the production chain, i.e. at reception by the processors and at the pre-drying step. Corn samples were more frequently contaminated with Fusarium sp. (100%) and Penicillium sp. (84.1–95.3%) than Aspergillus sp. (5.6–19.8%). Fumonisin B₁ (FB₁) was detected in all samples from the two points in both crop-years. FB₁ levels ranged 0.02–11.83 µg g^?1 in the reception and 0.02–10.98 µg g^?1 in the pre-drying samples of the 2003 crop. Samples from the 2004 crop showed FB₁ levels ranging 0.03–12.04 µg g^?1 in the reception and 0.06–7.74 µg g^?1 in the pre-drying samples. FB₂ levels ranged 0.02–5.25 µg g^?1 in the reception and 0.01–7.89 µg g^?1 in the pre-drying samples (2003 crop-year). In samples from the 2004 crop, FB₂ levels ranged 0.02–6.12 µg g^?1 in the reception and 0.05–3.47 µg g^?1 in the pre-drying samples. Low fumonisin levels were detected in most corn samples used by processors in the Northern region of Paraná State, showing a decreasing trend in fumonisin contamination over the years.     

Formation Mechanism and Synthesis of Apatite-Type Structure Ba2+xLa8−x(SiO4)6O2−δ

The formation process of Ba₂La₈(SiO₄)₆O₂ was clarified using thermogravimetry–differential thermal analysis (TG-DTA) and a high-temperature powder X-ray diffraction (HT-XRD) method. Phase changes identified from the HT-XRD data surprisingly corresponded to the weight loss and/or endothermic peaks observed in the TG-DTA curves. Raw material with the composition Ba₂La₈(SiO₄)₆O₂ was completely reacted at 1400°C and produced only an apatite-type compound without a secondary phase. Moreover, the synthesis of Ba_{2+ x} La_{8− x} (SiO₄)₆O_2−δ crystals with x = 0–2 was attempted using a solid-state reaction.     

Optimization of Set-up Conditions for Stability of The Centerless Grinding Process

The stability of the centerless grinding process is very sensitive to the set-up conditions due to the uniqueness of the work-holding system. Centerless grinding produces precision components with high productivity only when the set-up condition is optimally chosen. This paper describes the effect of set-up conditions on three stability criteria of the centerless grinding system. It also presents guidelines for determining proper set-up conditions to avoid spinners, chatter vibration and roundness problems. Finally, an algorithm for providing the optimum set-up condition based on process aims is proposed and the simulation results are discussed.     

深基坑工程动态施工反演分析与变形预报

提出了动态施工反演分析的思想，即在常规的反分析过程中引入逐步开挖和逐道支撑的动态施工因素，以求仿真模拟工程实际情况，进而为相继施工阶段的变形预报提供可靠保证。文中基于任意施工阶段间围护墙体变形与内支撑梁轴力的增量测值和施工ＦＥＭ优化反演分析法，反推了各土层的弹性模量系数，给出了作用在墙体两侧的土压力分布，并预报各相继施工阶段的墙体和土体变形、内力及内支撑梁轴力。