Amyloid beta-protein deposition in the leptomeninges and cerebral cortex

To further investigate the process of amyloid beta-protein (Abeta) deposition, we determined, using sensitive enzyme immunoassays, the levels of Abeta40 and Abeta42 (Abetas) in the soluble and insoluble fractions of the leptomeninges (containing arachnoid mater and leptomeningeal vessels) and cerebral cortices from elderly control subjects showing various stages of Abeta deposition and from patients affected by Alzheimer's disease (AD). In both locations, insoluble Abeta levels were higher by orders of magnitude than soluble Abeta levels. Soluble Abeta levels in cortices were much lower than those in leptomeninges. In insoluble Abeta in the cortex, Abeta42 was by far the predominant species, and Abeta42 in AD cortices was characterized by the highest degree of modifications in the amino terminus. In contrast, this Abeta42 predominance was not observed in insoluble Abeta in the leptomeninges, which were found to be able to accumulate Abetas to an extent similar to that in the cortex, on a weight basis. The levels of insoluble Abeta in the leptomeninges or cortex generally correlated with the degree of cerebral amyloid angiopathy or the abundance of senile plaque, respectively. However, the presence of plaque-free cortical samples showing significant levels of insoluble Abeta42 suggests that biochemically detectable Abeta accumulation precedes immunocytochemically detectable Abeta deposition in the cortex.     

Effect of inorganic salt on adsorption of sodium alkyl sulfates and fatty acid sodium salts from aqueous solution onto ion exchange resins

The adsorption isotherms of sodium salts of alkyl sulfonic acid and fatty acid with various carbon numbers onto ion exchange resins were measured in the absence and in the presence of sodium chloride in aqueous solutions. In the absence of the inorganic salt, the amount of adsorption remarkably increased with an increase in the length of alkyl groups in the adsorbates. Furthermore, the amount of adsorption apparently decreased with addition of sodium chloride into the solutions and almost reached a constant value at high concentrations of NaCl. This behavior strongly suggested that the electrostatic interaction on the adsorption decreased with increasing salt concentration and that the effect of hydrophobic interaction seems to play an important role on adsorption.     

Studying re-opened bugs in open source software

Bug fixing accounts for a large amount of the software maintenance resources. Generally, bugs are reported, fixed, verified and closed. However, in some cases bugs have to be re-opened. Re-opened bugs increase maintenance costs, degrade the overall user-perceived quality of the software and lead to unnecessary rework by busy practitioners. In this paper, we study and predict re-opened bugs through a case study on three large open source projects—namely Eclipse, Apache and OpenOffice. We structure our study along four dimensions: (1) the work habits dimension (e.g., the weekday on which the bug was initially closed), (2) the bug report dimension (e.g., the component in which the bug was found) (3) the bug fix dimension (e.g., the amount of time it took to perform the initial fix) and (4) the team dimension (e.g., the experience of the bug fixer). We build decision trees using the aforementioned factors that aim to predict re-opened bugs. We perform top node analysis to determine which factors are the most important indicators of whether or not a bug will be re-opened. Our study shows that the comment text and last status of the bug when it is initially closed are the most important factors related to whether or not a bug will be re-opened. Using a combination of these dimensions, we can build explainable prediction models that can achieve a precision between 52.1–78.6 % and a recall in the range of 70.5–94.1 % when predicting whether a bug will be re-opened. We find that the factors that best indicate which bugs might be re-opened vary based on the project. The comment text is the most important factor for the Eclipse and OpenOffice projects, while the last status is the most important one for Apache. These factors should be closely examined in order to reduce maintenance cost due to re-opened bugs.     

Topology optimization for fluid–thermal interaction problems under constant input power

This paper deals with density-based topology optimization considering fluid and thermal interactions, in which the Navier–Stokes and heat transport equations are coupled. We particularly focus on designing heat exchangers. In the engineering context, heat exchangers are designed while considering a certain amount of input power. Therefore it is important to maximize the performance of a heat exchanger under a constant input power. In this paper we propose a way to control the input power by introducing an extra integral equation. To be more precise, in the fluid analysis, the inlet pressure is determined by solving the extra integral equation together with the Navier–Stokes equation. By doing this we can keep the inlet power constant even when the flow channels are changed in the optimization process. Consequently, the system of equations of the fluid field takes an integrodifferential form. On the other hand, in the heat transport analysis, a single governing equation is defined for simultaneously modeling both the solid and fluid parts. The design variable is a fluid fraction whose distribution represents the topology of the solid and fluid domains. When designing heat exchangers, two different heat conditions are considered in the formulation of the optimization problems, namely temperature-dependent and temperature-independent heat sources. Through the numerical examples for designing flow channels in a heat exchanger, it is shown that distinct topologies can be obtained according to the input power and the heat source conditions.     

General topology optimization method with continuous and discrete orientation design using isoparametric projection

A general topology optimization method, which is capable of simultaneous design of density and orientation of anisotropic material, is proposed by introducing orientation design variables in addition to the density design variable. In this work, the Cartesian components of the orientation vector are utilized as the orientation design variables. The proposed method supports continuous orientation design, which is out of the scope of discrete material optimization approaches, as well as design using discrete angle sets. The advantage of this approach is that vector element representation is less likely to fail into local optima because it depends less on designs of former steps, especially compared with using the angle as a design variable (Continuous Fiber Angle Optimization) by providing a flexible path from one angle to another with relaxation of orientation design space. An additional advantage is that it is compatible with various projection or filtering methods such as sensitivity filters and density filters because it is free from unphysical bound or discontinuity such as the one at θ = 2π and θ = 0 seen with direct angle representation. One complication of Cartesian component representation is the point‐wise quadratic bound of the design variables; that is, each pair of element values has to reside in a given circular bound. To overcome this issue, we propose an isoparametric projection method, which transforms box bounds into circular bounds by a coordinate transformation with isoparametric shape functions without having the singular point that is seen at the origin with polar coordinate representation. A new topology optimization method is built by taking advantage of the aforementioned features and modern topology optimization techniques. Several numerical examples are provided to demonstrate its capability. Copyright © 2014 John Wiley & Sons, Ltd.     

Experimental study of bubbly swirling flow in a vertical tube using ultrasonic velocity profiler (UVP) and wire mesh sensor (WMS)

Two-phase air-water bubbly swirling flow through a pipe is a complex turbulent flow and its prediction is still challenging. The present paper describes the experimental investigation of the air-water bubbly swirling flow in vertical co-current flow. Swirling flow is induced by a twisted tape in a 20 mm inner diameter pipe. The flow is investigated using Ultrasonic velocity profiler (UVP), which allows the measurement of liquid and gas velocities simultaneously. Furthermore, simultaneous measurement of void fraction is performed using Wire mesh sensor (WMS). The experimental results reveal that swirling flow has significant impact on bubbles’ distribution. In low liquid flow rate, the average bubble velocity is fairly uniform along the radial position and void fraction increases in the near wall region. However, increasing liquid flow rate at constant gas flow rate leads to increase in void fraction in the core region, this is mainly due to drift velocity which is affected by centrifugal force. Experimental findings and parametric trends based on the effects of swirling flow are summarized and discussed.     

Investigation of radiation-induced surface activation effect in austenitic stainless steel under ultraviolet and γ-ray irradiations

The radiation-induced surface activation (RISA) effect will be applied to the core design in supercritical light water reactor (SCWR) in order to achieve a high performance with excellent economy and safety. The purpose of the present study is to investigate the RISA effect in the candidate fuel cladding materials in SCWR such as PNC1520. The change of weldability due to RISA effect and the related microstructure analysis were performed in oxidized PNC1520 and 304 stainless steel with various oxidization periods. The phases contained in the surface oxide layer of the present specimen were identified as Fe₂CrO₄, γ-Fe₂O₃, and Fe₂O₃. The lifetime of 13.8 days for wettability improving factor was confirmed in the ultraviolet (UV) irradiation. Meanwhile, the long life of 13.8 days and short life of 0.8 days for wettability improving factors were identified in the γ-ray irradiation. Based on the fact that the band gap energies of Fe₂CrO₄, γ-Fe₂O₃, and Fe₂O₃ were, respectively, 2.1, 2.0, and 2.2 eV, and the photo energies of UV and γ-ray irradiation were 4.48 eV and 13.3 MeV, it is therefore clarified that the hydrophilization on the oxide layer is ascribed to the RISA effect.     

Coagulation process of soymilk characterized by electrical impedance spectroscopy

Soymilk coagulation process is the most important step in tofu making. An experimental setup was developed to control the coagulation temperature and heating rate by ohmic heating and to perform impedance measurement in time-sharing mode. Soymilk coagulation process was characterized by electrical impedance spectroscopy. Frequency 10 kHz was chosen to analyze the coagulation process. Normalized conductivity was useful in determination of the endpoint of soymilk coagulation process. The coagulation process was considered as two successive first-order reactions. The rate constant in the first stage was 10 times higher than that in the second stage, both rate constants increased with coagulation temperature. The activation energy in the second stage was three times greater than that in the first stage. The successive reaction process was elucidated by using soymilk coagulation mechanism. The use of impedance measurement to analyze the coagulation process provides a basis for the control of soymilk coagulation process.     

Patterning of Non-Linear Optical Crystals in Glass by Laser-Induced Crystallization

This paper reports recent progress in the patterning of non-linear optical crystals on the glass surface by laser irradiation. Two techniques for the writing of crystal lines have been developed, i.e., rare-earth (samarium) atom heat processing and transition metal atom heat processing, in which a continuous wave Nd:YAG laser (wavelength: λ=1064 nm) is irradiated to the glasses containing rare-earth (RE: Sm³⁺, Dy³⁺) ions or transition metal (TM: Ni²⁺, Fe²⁺, V⁴⁺) ions. The writing of crystal lines such as β-BaB₂O₄, Sm _x Bi_{1− x} BO₃, and Ba₂TiGe₂O₈ showing second harmonic generations has been successful. It is clarified from the azimuthal dependence of second harmonic intensity and polarized micro-Raman scattering spectra that crystal lines consist of highly oriented crystals along the crystal line growth direction. It is also possible to write two-dimensional crystal bending or curved lines by just changing the laser scanning direction. The mechanism of the laser-induced crystallization has been proposed.     

Environmentally friendly coloured materials: cellulose/titanium dioxide/inorganic pigment composite spherical microbeads prepared by viscose phase-separation method

In order to develop environmentally friendly coloured materials, cellulose composite spherical microbeads hybridised with titanium dioxide (TiO₂) particles and inorganic pigment were prepared by a phase-separation method using viscose and an aqueous solution containing sodium polyacrylate. Findings regarding the relationships between cellulose xanthate and the electronic characteristics of TiO₂ particles used in the cellulose/inorganic material composite sphering process are also reported. These findings suggest that the location of TiO₂ particles in cellulose microbeads is related to electrical repulsion between the xanthate (CSS⁻) group and TiO₂. The use of TiO₂ powder as colour pigment is limited, as its colour is white. The cellulose composite spherical microbeads covered with TiO₂ and Fe₂O₃ particles were developed by addition of iron oxide (Fe₂O₃). Their surfaces were viewed by laser microscope and using SEM images. These composite microbeads retained the photocatalytic property of TiO₂. Cellulose/TiO₂/Fe₂O₃ composite spherical microbeads with both colour function and photocatalytic properties were successfully prepared.