An aqueous suspension system for phospholipase D-mediated synthesis of PS without toxic organic solvent

Enzymatic synthesis of PS by phospholipase D (PLD)-mediated transphosphatidylation in an aqueous media was investigated. The purpose of this study was to establish a novel synthetic method where no toxic organic solvents were used. An attempt to react soybean lecithin (simply dispersed in an aqueous buffer) with an aqueous solution of l-serine and PLD was unsuccessful, giving only 20% of PS. By contrast, a suspension of lecithin adsorbed on fine powders such as silica was effectively converted into PS in an aqueous solution of l-serine and PLD. After screening various powders for use as the lecithin adsorbent, calcium sulfate was found to be the best with respect to lecithin conversion. In addition, calcium sulfate did not require prior adsorption of lecithin (i.e., the reaction proceeded effectively simply by adding the powder to an aqueous mixture of lecithin, l-serine, and PLD). With this “aqueous suspension system” of calcium sulfate, up to 180 mg/mL lecithin was completely converted, resulting in more than 80% PS in 24 h. The synthesized PS could easily be recovered from the powder by extracting with a mixture of n-hexane, ethanol, and diluted HCl.     

Fourier synthesis image reconstruction by use of one-dimensional position-sensitive detectors

An improvement of Fourier synthesis optics for hard x-ray imaging is described, and the basic performance of the new optics is confirmed through numerical simulations. The original concept of the Fourier synthesis imager utilizes nonposition-sensitive hard x-ray detectors coupled to individual bigrid modulation collimators. The improved concept employs a one-dimensional position-sensitive detector (such as a CdTe strip detector) instead of the second grid layer of each bigrid modulation collimator. This improves the imaging performance in several respects over the original design. One performance improvement is a two-fold increase in the average transmission, from 1/4 to 1/2. The second merit is that both the sine and cosine components can be derived from a single grid-detector module, and hence the number of imaging modules can be halved. Furthermore, it provides information along the depth direction simultaneously. This in turn enables a three-dimensional imaging hard x-ray microscope for medical diagnostics, incorporating radioactive tracers. A conceptual design of such a microscope is presented, designed to provide a field of view of 4 mm and a spatial resolution of 400 microm.     

Cautionary observations on preparing and interpreting brain images using molecular biology-based staining techniques

Though molecular biology-based visualization techniques such as antibody staining, in situ hybridization, and induction of reporter gene expression have become routine procedures for analyzing the structures of the brain, precautions to prevent misinterpretation have not always been taken when preparing and interpreting images. For example, sigmoidal development of the chemical processes in staining might exaggerate the specificity of a label. Or, adjustment of exposure for bright fluorescent signals might result in overlooking weak signals. Furthermore, documentation of a staining pattern is affected easily by recognized organized features in the image while other parts interpreted as "disorganized" may be ignored or discounted. Also, a higher intensity of a label per cell can often be confused with a higher percentage of labeled cells among a population. The quality, and hence interpretability, of the three-dimensional reconstruction with confocal microscopy can be affected by the attenuation of fluorescence during the scan, the refraction between the immersion and mounting media, and the choice of the reconstruction algorithm. Additionally, visualization of neurons with the induced expression of reporter genes can suffer because of the low specificity and low ubiquity of the expression drivers. The morphology and even the number of labeled cells can differ considerably depending on the reporters and antibodies used for detection. These aspects might affect the reliability of the experiments that involves induced expression of effector genes to perturb cellular functions. Examples of these potential pitfalls are discussed here using staining of Drosophila brain.     

Coagulation mechanism of salt solution-extracted active component in Moringa oleifera seeds

This study focuses on the coagulation mechanism by the purified coagulant solution (MOC-SC-PC) with the coagulation active component extracted from M. oleifera seeds using salt solution. The addition of MOC-SC-PC tap water formed insoluble matters. This formation was responsible for kaolin coagulation. On the other hand, insoluble matters were not formed when the MOC-SC-PC was added into distilled water. The formation was affected by Ca2+ or other bivalent cations which may connect each molecule of the active coagulation component in MOC-SC-PC and form a net-like structure. The coagulation mechanism of MOC-SC-PC seemed to be an enmeshment of Kaolin by the insoluble matters with the net-like structure. In case of Ca2+ ion (bivalent cations), at least 0.2 mM was necessary for coagulation at 0.3 mgC l-1 dose of MOC-SC-PC. Other coagulation mechanisms like compression of double layer, interparticle bridging or charge neutralization were not responsible for the coagulation by MOC-SC-PC.     

Human and chimpanzee face recognition in chimpanzees (Pan troglodytes): Role of exposure and impact on categorical perception.

The respective influences of exposure and inborn neural networks on conspecific and nonconspecific face processing remain unclear. Although the importance of exposure in the development of object and face recognition in general is well documented, studies explicitly comparing face recognition across species showed a species-specific effect. For instance, laboratory monkeys exposed daily to human faces were better at discriminating monkeys than humans, suggesting that the role of exposure may not be the only factor affecting cross-species recognition. In the present study, the authors investigated conspecific and nonconspecific face recognition in chimpanzees (Pan troglodytes) from 2 primate centers that provided different exposure to chimpanzee and human faces. The authors showed that the chimpanzees from the center providing more exposure to human faces than to chimpanzee faces were better at discriminating human faces than they were at discriminating chimpanzee faces. The chimpanzees from the other center did not show the same effect. A computational simulation was developed to evaluate the average similarities among human pictures and among chimpanzee pictures. Both categories were comparable. Chimpanzees' scores were significantly correlated with the similarity coefficients. Overall, the results show that exposure is a critical determinant in conspecific and nonconspecific face recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cermet-type hydrogen separation membrane obtained from fine particles of high temperature proton-conductive oxide and palladium

A mixed ionic and electronic conducting hydrogen separation membrane, which consisted of proton-conductive oxide and metallic palladium, was fabricated. A porous alumina tube was employed as a support, and proton-conductive oxide particles were introduced into a microporous top layer of the support by an impregnation method. Palladium particles were deposited into the same porous layer by chemical vapor deposition. Hydrogen permeated preferentially via the membrane thus obtained with a hydrogen permeance (PH₂) of 1.2 × 10^− 9 mol·m^− 2·s^− 1·Pa^− 1 at 873 K. Selectivity for hydrogen (PH₂/PN₂) increased with the operating temperature due to an increase in proton conductivity of the membrane, and PH₂/PN₂ = 5.7 was attained at 873 K.     

Investigation of gas-liquid interface in atmospheric-pressure micro plasma with solution

An atmospheric-pressure glow-discharge micro plasma in contact with liquid paraffin is stably generated by using a capacitively coupled plasma method with a mesh electrode. When characteristics of the plasma are measured in the boundary between the micro plasma (gas-phase) and liquid paraffin (liquid-phase) using optical emission spectroscopy, spectrum peaks of the emission of CH and C₂ which dissociate from paraffin are observed. The result indicates that solution can feed particles to the plasma at gas-liquid interface and this plasma is accordingly expected to promote an attractive plasma process for creating materials consisting of elements in various solutions.     

Control of swarm behavior in crossing pedestrians based on temporal/spatial frequencies

In the densely-populated urban areas, pedestrian flows often cross each other and congestion is caused. The congestion makes us feel uncomfortable and sometimes leads to pedestrian accidents. To reduce the congestion or the risk of accidents, it is required to control the swarm behavior of pedestrian flows. This paper proposes modeling and controlling method of the crossing pedestrian flows. In the social/urban engineering, it is well known that the swarm behavior with a diagonal stripe pattern emerges in the crossing area of the flows. This is a self-organized phenomenon caused by the local collision avoidance effect of the pedestrians. To control the macroscopic behavior of the flows, we utilize this self-organized phenomenon. Firstly, we propose the continuum model of the crossing pedestrian flows. In the continuum model, the dynamic change of the congestion in the diagonal stripe pattern is simulated as the density. Secondly, the novel control method to improve average flow velocity is proposed based on the model. The proposed method utilizes the dynamic interaction between the diagonal stripe pattern and guides, who are moving in the flows. The authors derive the control algorithm through an analysis on the temporal and spatial frequencies of the crossing flows. The validity is verified with simulations using the continuum model. Moreover, we apply the proposed method to the particle model, assuming the actual pedestrians.     

Capillary rise properties of porous mullite ceramics prepared by an extrusion method with various diameters of fiber pore formers

Porous mullite ceramics with unidirectionally oriented pores were prepared by an extrusion method using rayon fibers as the pore formers. Rayon fibers of 8.1, 9.6, 16.8, and 37.6 μm in diameter were used as the pore formers and were kneaded with alumina powder, kaolin clay, China earthen clay, and water to form pastes. These pastes were extruded into cylindrical tubes, dried, and fired at 1500 °C for 4 h. The apparent porosities ranged from 45.7 to 48.2 %. The pore size distributions showed a sharp peak at 9.4, 10.0, 15.6, and 30 μm with increasing fiber diameters. The height of the capillary rise was 1780, 1670, 1320, and 950 mm with increasing fiber diameter. The maximum capillary rise is much higher than previously reported. The contact angle and effective pore radius that determine the capillary rise ability were calculated by fitting the capillary rise curves using the Fries and Dreyer’s equation.     

Near-net-shape forming of Al-Al3Ni functionally graded material over eutectic melting temperature

A possibility to make near-net-shape functionally graded material (FGM) products has been examined. The FGM billets having a graded volume fraction of Al₃Ni in thickness direction were machined from an Al-Al₃Ni FGM thick-walled tube manufactured by a vacuum centrifugal method. Billets, which were set in the container for the backward extruding, were heated to 650 °C to 680 °C, at which temperature the FGM becomes a mixture of molten aluminum eutectic and solid intermetallics. Then, billets were extruded successfully to FGM cups by a semisolid forming, except at 650 °C. Residual bulky Al₃Ni particles are found at higher temperature. Thus, an optimum operation temperature is found to be around 660 °C, because bulky Al₃Ni particles transform to fine spheroidal or fibrous shape after the forming. The volume fraction of intermetallics at the bottom region of the cup was condensed more than 60 vol pct in a proper billet setting.