A new technique for generating regularly spaced crazes to facilitate piece dyeing of polypropylene filaments

The aim of this study was to investigate crazing that generates regular crazes in polymeric fibers. For carrying out this study, we designed and fabricated an experimental apparatus for generating crazes on polypropylene (PP) filaments. By an optical micrograph and a laser scanning micrograph of the surface and cross‐section of the filaments, it was confirmed that the crazes were generated on the surface of the filaments. Optical microscopes and measurements of the craze morphology on the filaments showed that approximately 30–50% of the contact area was crazed. As the crazing tension increased, the interval between the crazes increased, but the width of the crazes did not change significantly. Moreover, it was confirmed that the filaments had a homogenous crazed structure and pores were formed in their structure. The crazing process did not affect the strength of the crazed filaments significantly; the crazing process decreased the light transmittance of the filaments. The acid dyeing was adsorbed onto crazed region of PP filaments. These crazes in the filaments have the potential to lead to new methods for dyeing PP fibers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Single cell reporter assay using cell surface displayed Vargula luciferase

Reporter genes such as firefly luciferase are common tools to monitor gene expression in various systems. As reporter gene represents the expression level of the gene of interest with its enzyme activity, firefly luciferase is most frequently used because its luminescent activity is highly sensitive and less time consumable for assay. However, since firefly luciferase is expressed internally in the cell, lysis of the cell is a critical step, and thus it is difficult to monitor the gene expression level continuously. In this report, we utilized secretive Vargula hilgendorfii luciferase modified to cell surface displayed one by fusing with human EGFR transmembrane sequence. This modified Vargula luciferase was expressed on cell surface without losing its bioluminescent activity. Co-transfection with secretive alkaline phosphatase showed that the behaviors of cell surface displayed Vargula luciferase and secretive alkaline phosphatase are comparable to each other. Furthermore, the luminescence of a single cell expressing cell surface displayed Vargula luciferase can be monitored by using photon counting CCD camera, which indicates that this reporter gene can monitor gene expression in a single cell without cell lysis.     

Minimum energy path search for a manipulator in consideration of all nonlinear characteristics by GA and its experiments

The dissipated energy even of a manipulator must be decreased in order to improve the environment of the earth. This paper describes an optimal path which minimizes the dissipated energy in PTP motions of a vertically articulated manipulator. The dynamic equation of the manipulator is nonlinear due to centrifugal, Coriolis, gravity, and Coulomb friction forces. Moreover the driving system of the joints is also nonlinear in that the generating torque is expressed by a third‐degree polynomial with respect to current. Therefore, an optimal path cannot be obtained by solving a two‐point boundary‐value problem analytically. In this paper an optimal path is searched for by a Genetic Algorithm (GA) in cases in which all kinds of nonlinear characteristics of the manipulator, including the driving system, are taken into consideration. The obtained optimal velocity functions are applied to a vertically articulated manipulator with two direct‐drive motors. The dissipated energy is measured by integrating the input power to the motors. Experimental results agree with the simulation values only when all kinds of nonlinearity are taken into consideration. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 26–34, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20437 Copyright © 2006 Wiley Periodicals, Inc.     

Synthesis of europium-doped yttrium hydroxide and yttrium oxide nanosheets

A new approach has been developed for the preparation of Y(OH)₃:Eu and Y₂O₃:Eu nanosheets using the sol–gel method and hydrothermal reactions. XRD patterns showed that the product was purely hexagonal-phase Y(OH)₃. TEM images revealed that the nanosheets are square shaped (1 × 1 μm²) with a thickness of several tens of nanometers. In addition, it was found that cubic-phase Y₂O₃ nanosheets can be obtained by calcination of Y(OH)₃ at 900 °C for 1 h. More importantly, the thus-prepared Y(OH)₃:Eu and Y₂O₃:Eu nanosheet phosphors were found to exhibit a relatively high photoluminescence (PL) intensity.     

Comparison of efficiency of terminal differentiation of oligodendrocytes from induced pluripotent stem cells versus embryonic stem cells in vitro

Oligodendrocytes are the myelinating cells of the central nervous system (CNS), and defects in these cells can result in the loss of CNS functions. Although oligodendrocyte progenitor cells transplantation therapy is an effective cure for such symptoms, there is no readily available source of these cells. Recent studies have described the generation of induced pluripotent stem cells (iPS cells) from somatic cells, leading to anticipation of this technique as a novel therapeutic tool in regenerative medicine. In this study, we evaluated the ability of iPS cells derived from mouse embryonic fibroblasts to differentiate into oligodendrocytes and compared this with the differential ability of mouse embryonic stem cells (ES cells). Experiments using an in vitro oligodendrocyte differentiation protocol that was optimized to ES cells demonstrated that 2.3% of iPS cells differentiated into O4⁺ oligodendrocytes compared with 24.0% of ES cells. However, the rate of induction of A2B5⁺ oligodendrocyte precursor cell (OPC) was similar for both iPS-derived cells and ES-derived cells (14.1% and 12.6%, respectively). These findings suggest that some intracellular factors in iPS cells inhibit the terminal differentiation of oligodendrocytes from the OPC stage.     

Liquid Crystalline Inorganic Nanosheet Colloids Derived From Layered Materials

Inorganic layered crystals such as clay minerals, layered niobates, and graphite are exfoliated in solvents to form colloidal dispersions of extremely thin inorganic nanosheets. Recently, the liquid crystal phases of these “nanosheet colloids” have been rediscovered and are attracting interest as new types of inorganic liquid crystals. The huge anisotropy of the mesogenic nanosheets compared to other liquid crystal systems is an important feature of the nanosheet liquid crystals for fundamental studies in the fields of colloid science and soft matter physics. In addition, the rich functionalities intrinsic to inorganic materials open a variety of applications such as smart colloids and composite materials with structural regularity. In this article, the recent progress of the emerging new materials of inorganic nanosheet liquid crystals is reviewed with a focus on the behaviors of each system, alignment by external field, and theoretical aspects.     

Protein-based nanotubes for biomedical applications

This review presents highlights of our latest results of studies directed at developing protein-based smart nanotubes for biomedical applications. These practical biocylinders were prepared using an alternate layer-by-layer (LbL) assembly of protein and oppositely charged poly(amino acid) into a nanoporous polycarbonate (PC) membrane (pore diameter, 400 nm), with subsequent dissolution of the template. The tube wall typically comprises six layers of poly-L-arginine (PLA) and human serum albumin (HSA) [(PLA/HSA)(3)]. The obtained (PLA/HSA)(3) nanotubes (NTs) can be dispersed in aqueous medium and are hydrated significantly. Several ligands for HSA, such as zinc(II) protoporphyrin IX (ZnPP), were bound to the HSA component in the cylindrical wall. Similar NTs comprising recombinant HSA mutant, which has a strong binding affinity for ZnPP, captured the ligand more tightly. The Fe(3)O(4)-coated NTs can be collected easily by exposure to a magnetic field. The hybrid NTs bearing a single avidin layer as an internal wall captured biotin-labeled nanoparticles into the central channel when their particle size is sufficiently small to enter the pores. The NTs with an antibody surface interior entrapped human hepatitis B virus with size selectivity. It is noteworthy that the infectious Dane particles were encapsulated completely into the hollows. Other HSA-based NTs having an α-glucosidase inner wall hydrolysed a glucopyranoside to yield α-D-glucose. A perspective of the practical use of the protein-based NTs is also described.     

Growth control of genetically modified cells using an antibody/c-Kit chimera

Gene therapy has been regarded as an innovative potential treatment against serious congenital diseases. However, applications of gene therapy remain limited, partly because its clinical success depends on therapeutic gene-transduced cells acquiring a proliferative advantage. To address this problem, we have developed the antigen-mediated genetically modified cell amplification (AMEGA) system, which uses chimeric receptors to enable the selective proliferation of gene-transduced cells. In this report, we describe mimicry of c-Kit signaling and its application to the AMEGA system. We created an antibody/c-Kit chimera in which the extracellular domain of c-Kit is replaced with an anti-fluorescein single-chain Fv antibody fragment and the extracellular D2 domain of the erythropoietin receptor. A genetically modified mouse pro-B cell line carrying this chimera showed selective expansion in the presence of fluorescein-conjugated BSA (BSA-FL) as a growth inducer. By further engineering the transmembrane domain of the chimera to reduce interchain interaction we attained stricter ligand-dependency. Since c-Kit is an important molecule in the expansion of hematopoietic stem cells (HSCs), this antibody/c-Kit chimera could be a promising tool for gene therapy targeting HSCs.