Preparation and Characterization of Fine-Grained 3Y-TZP/BaFe12O19 In Situ Composites

Composites of BaFe₁₂O₁₉ particles dispersed throughout a 3-mol%-yttria-doped zirconia (3Y-TZP) matrix have been prepared using the pressureless reactive sintering of 3Y-TZP, BaCO₃, and γ-Fe₂O₃ powders. The reaction behavior of the mixed powder was studied with an in situ , high-temperature powder X-ray diffraction technique. The composite that was sintered at 1300°C consisted of submicrometer-sized 3Y-TZP grains and BaFe₁₂O₁₉ particles; the size of the 3Y-TZP grains was ∼100-300 nm, and the size of the BaFe₁₂O₁₉ particles was ∼200-500 nm. Based on the grain size, most of the BaFe₁₂O₁₉ grains presumably had a single-magnetic-domain structure. The 3Y-TZP/20-wt%-BaFe₁₂O₁₉ composite showed high magnetization and coercivity values, despite the low concentration of ferromagnetic phase. Preliminary mechanical tests revealed that the composite possessed moderately good mechanical properties.     

Ordered Mesoporous Aluminosilicates Assembled from Dissolved LTA Precursors

Aluminosilicate sols containing Si–O–Al bonds were obtained by dissolving zeolite LTA crystals in HCl solution. The solutions were used as single-source molecular precursors of silicon and aluminum. Highly ordered cage-like mesoporous aluminosilicates with Si/Al ratios ranging from 13 to 35 were synthesized using PEO₁₀₆PPO₇₀PEO₁₀₆ triblock copolymer aqueous solution and LTA dissolved in HCl solution under mild acidic conditions.     

Phase behavior and hydrated solid structure in lysophospholipid/long-chain alcohol/water system and effect of cholesterol addition

Phase behavior in lysophospholipid/long-chain alcohol/water system at 80°C was investigated using hexanol and oleyl alcohol as the long-chain alcohol. Similarly to hydrophilic surfactant, a micellar phase in a lysophospholipid/water system transitioned to a lamellar liquid-crystalline phase by the addition of long-chain alcohol. In the oleyl alcohol system the lamellar liquid-crystalline phase was observed in wider region compared to the hexanol system. The effect of cholesterol addition on the phase behavior was also studied. The region of liquid-crystalline phase and (reverse micellar + liquid-crystalline + water) phase shifted towards higher lysophospholipid concentrations. The structure of hydrated solid as well as the transition between lamellar liquid-crystalline phase and hydrated solid was analyzed by X-ray scattering measurement and differential scanning calorimetry measurement. It was revealed that the hydrated solid was α-type crystals with lamellar structure. The hydrated solid (gel)-liquid crystal transition temperature gradually decreased with increasing oleyl alcohol concentration and the decrement was enhanced by the addition of cholesterol.     

High-Temperature Fracture Energy of Superplastically Forged Silicon Nitride

The fracture energy of superplastically forged silicon nitride, where rodlike silicon nitride grains are aligned in one direction, was investigated at high temperatures from 1100° to 1300°C and at room temperature. Bending tests using chevron-notched beams were conducted at two displacement rates, 0.05 and 0.005 mm/min. The superplastically forged silicon nitride showed remarkably high fracture energies, 200–630 J/m². The fracture energy was largely dependent on the temperature and the displacement rate. The high fracture energy was attributed to grain pullout enhanced by the softened grain-boundary glassy phase and the aligned rodlike grains.     

An alternate computational architecture for advanced process engineering

An algorithm for equation-oriented (EO) flowsheeting to which the interfacing of external modular procedures is readily allowed is presented. In the algorithm, all the process units in a flowsheet are solved simultaneously in an EO environment while taking advantage of the external software as it is. The algorithm is the basis for the process simulator MIKAN. The simulator consists of two parts, namely EO main, which is the simulator's executive, and add-on blocks to incorporate external procedures. EO main also serves to solve separation processes. The PBM (Pseudo-Binary-Mixture)-based algorithm for separation processes (Ishii & Otto, 2008) is fully exploited in EO main. The equations of the entire system are composed of a set of equations for separation processes and sets of equations representing the input-output relation of each add-on block. The input-output relation is obtained by numerical perturbation where all the component flow rates are perturbed collectively. Although the proposed perturbation is simple and significantly less expensive, it is very reliable since the interactions among the input variables affecting the output are fully accounted for.Robustness, flexibility and efficiency of the new algorithm have been confirmed by its implementation. A serious drawback with the EO approach is the difficult accessibility to the user when incorporating new or external process models. Easy accessibility is an important attribute of the new algorithm, even though the simulator's executive is highly integrated and complex. It is significant that the derivative information at various levels of a flowsheet is easily obtained in the algorithm. The novel algorithmic capabilities of the algorithm provide a robust platform for the next stage of advanced process engineering.     

Physicochemical analysis of liposome membranes consisting of model lipids in the stratum corneum

Lamellar lipid layers in the stratum corneum (SC), the outermost layer of the skin, act as a primary permeability barrier to protect the body. The roles of SC lipid composition and membrane structure in skin barrier function have been extensively investigated using ex-vivo SC samples and reconstructed SC lipids in the form of multi-lamellar lipids or liposomes. The primary lipids, especially ceramide, have been found to be highly important. Atopic dermatitis (AD) is a well-known chronic inflammatory skin disease with immunologic and epidermal abnormalities of the permeability barrier; therefore, a comparison of SC lipids in AD skin with those in normal skin is a promising method to explore the mechanisms of skin barrier function. Here, we focused on the effect of sphingoids (ceramide metabolites and a minor component of the SC lipids) and their content/species on skin barrier function. A significant difference in the leakage ratio was observed between model SC lipid liposomes with a different sphingolipid ratio (sphingosine/sphinganine), with a value of 5.43 for normal skin vs. 14.3 for AD skin. This result shows a good concordance with AD mouse experiments. Therefore, an alteration in the composition of minor SC lipids resulting from a ceramide metabolic abnormality can affect the membrane integrity (i.e., skin barrier function). Small angle X-ray scattering (SAXS) measurements revealed no distinct differences in the SAXS pattern between the 3 models, with all models forming a rigid membrane (i.e., a nearly hydrated solid). According to increasing the temperature, the peaks indicated that the lamellar structures decreased in all models and that the lateral packing of lipids decreased, which suggested annealing or melting of the gel to a liquid crystal, although no distinct phase transition was observed through fluorescence anisotropy measurements. Hence, we assume that the altered sphingoid composition triggers local membrane structural changes (i.e., formation of domains or clusters).     

Modelling the growth of carbon nanotubes produced by chemical vapor deposition

An improved model of C₂H₂ deposition for the growth of carbon nanotubes (CNT) in a horizontal tube reactor has been developed. This includes detailed gas-phase reactions of acetylene pyrolysis, and surface catalytic reactions for CNT growth. Based on this model, the mechanism of CNT growth has been studied by analyzing the change of the CNT growth rate for different growth conditions such as pressure, temperature, number of catalyst nanoparticles per unit area, and diameters of catalyst nanoparticles. The influence of gas-phase reactions and their products on CNT growth has also been evaluated. It is found that although C₂H₂ is the main contributor to the growth of CNTs, the contribution from the gas-phase products could not be ignored, especially at high temperature.     

An enhanced pseudo-binary-mixture (PBM) algorithm for multistage separation processes

A scale-shift approach is introduced to further refine the pseudo-binary-mixture (PBM) simultaneous correction procedure for the solution of multicomponent, multistage separation problems [Ishii, Y., & Otto, F. D. (2001). An efficient simultaneous correction procedure for multicomponent, multistage separation calculations for non-ideal systems. Computers and Chemical Engineering, 25, 1285–1298; & Ishii, Y., & Otto, F. D. (2003a). A method to extend the domain of convergence for difficult multicomponent, multistage separation problems. Computers and Chemical Engineering, 27, 855–868]. The scale-shift approach takes advantage of the fact that a solution to a stage-wise separation problem is more easily obtained the fewer the number of stages. In the approach the column specified in a given problem is initially downsized to a configuration having a small number of stages and then scaled up to the original one in a multiple-step manner. A solution is obtained at each scale-shift step and the results are used as a set of initial assumptions to solve the subsequent scaled-up problem. Combining the scale-shift approach along with the gradual non-ideal enhancing method with the PBM algorithm provides a more robust and efficient algorithm for the simulation and solution of difficult multicomponent, multistage separation problems including those involving non-ideal mixtures that are highly sensitive to the quality of initial values. A geometric consideration for the gradual non-ideal enhancing method and details of the unique procedure for the algebraic inversion of matrices employed in the algorithm are also presented.     

Mitochondrial Unfolded Protein Responses in White Adipose Tissue: Lipoatrophy,Whole-Body Metabolism and Lifespan

The mitochondrial unfolded protein response (UPR^mt) is a stress response mediated by the expression of genes such as chaperones, proteases, and mitokines to maintain mitochondrial proteostasis. Certain genetically modified mice, which defect mitochondrial proteins specifically in adipocytes, developed atrophy of the white adipose tissue, resisted diet-induced obesity, and had altered whole-body metabolism. UPR^mt, which has beneficial functions for living organisms, is termed “mitohormesis”, but its specific characteristics and detailed regulatory mechanism have not been elucidated to date. In this review, we discuss the function of UPR^mt in adipose atrophy (lipoatrophy), whole-body metabolism, and lifespan based on the concept of mitohormesis.     

Surface control of hydrophilicity and degradability with block copolymers composed of lactide and cyclic carbonate bearing methoxyethoxyl groups

Block copolymers of L-lactide (LA) and trimethylene carbonate (TMC) derivatives bearing methoxyethyl groups [poly(TMCM-MOE1OM)-block-PLLA] were employed as spin-coated films on substrates, and their hydrophilic and degradation behaviors were investigated. Changing the solvents for film preparation, film thickness, and copolymer composition ratios varied the contact angles in the range of 84.3° ± 2.8° at 269 nm thickness and 18.2° ± 2.5° at 15 nm thickness. These contact angles showed dynamic changes from hydrophobic to hydrophilic properties, probably due to the methoxyethoxyl groups connecting the flexible TMC moieties in the copolymer. Immersion into water or hexane affected the dynamic contact angles. X-ray photoelectron spectroscopy analyses revealed that a large amount of hydrophilic groups was segregated onto the surface, although both LA and TMC units existed. Such dynamic contact angle changes were delayed by the crystallization of polylactide. The hydrolyzed behaviors of these films were examined by quartz cell microbalance, showing a slow degradation process.