Surface grafting of poly(vinylamine) onto poly(ethylene) film by corona discharge‐induced grafting

Poly(vinylamine) (PVAm) was grafted on a poly(ethylene) (PE) film surface via the surface graft polymerization of N‐vinylformamide (NVF) and N‐vinylacetamide (NVA) and the subsequent hydrolysis of those grafted polymers. The surface was characterized by X‐ray photoelectron spectroscopy (XPS), contact angle, moisture absorption, and the leakage of electrostatic charge from the films. PNVF and PNVA were introduced onto the surface of the PE film successfully, in spite of the fact that the initiator for polymerization was a peroxide group. The grafted amounts of PNVF and PNVA were dependent on the grafting time. A PVAm‐grafted surface was obtained via the hydrolysis of the grafted PNVF. The grafted‐PNVA was not hydrolyzed under mild hydrolysis. The obtained PVAm‐grafted surface appeared to be useful for various applications, such as protein immobilization or chemical modification. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1583–1587, 1999     

The effect of copper and manganese on magnetic minor hysteresis loops in neutron irradiated Fe model alloys

Changes of magnetic minor hysteresis loops in pure Fe, Fe-1 wt% Mn, Fe-0.9 wt% Cu, and Fe-0.9 wt% Cu-1 wt% Mn model alloys after neutron irradiation have been studied. Minor-loop coefficients which are obtained from scaling relations between minor-loop parameters and in proportion to internal stress, were found to decrease in all model alloys after the irradiation to a fluence of 3.32 × 10¹⁹ n cm⁻². The decrease of the coefficients is larger for alloys including Cu and is enhanced by 1 wt% Mn addition. Such decrease implying the reduction of internal stress during irradiation is in contrast with changes of yield strength after the irradiation that increase with Cu and Mn contents. A qualitative explanation was given on the basis of the preferential formation of Cu precipitates along pre-existing dislocations which reduces internal stress of the dislocations.     

A novel way of enhancing the electrical and thermal stability of conductive epoxy resin–carbon black composites via the Joule heating effect for heating‐element applications

The influence of Joule heating treatments and carbon black (CB) on the electrical and thermal behavior of epoxy resin composites is well described in this article. The effect of CB and Joule heating on network structure characteristics, such as shrinkability, interparticle distance between conductive particles, crosslinking density, hardness, thermoelectric power, thermal conductivity, the thermal expansion coefficient, and scanning electron microscopy, of epoxy composites was investigated. The electrical conductivity (σ) of epoxy resin correlated with the volume fraction of CB and Joule heating treatment. σ increased continuously with increasing CB content, and Joule heating increased the level of σ, which makes it attractive for electronic utilization. The σ for fresh and Joule heating samples was recorded during heating–cooling cycles. The conduction mechanism of σ for epoxy composites was identified. The activation energy and hopping energy for two batches of epoxy as a function of CB content were estimated. The hopping distance, the state density at the Fermi level, and the radius of localized wave function versus CB content were evaluated. The current–voltage–temperature characteristics of fresh and Joule heating samples of epoxy composites were demonstrated. The thermal reliability was tested by means of temperature–time characteristics when certain applied power was on and off for several cycles. The specific heat and amount of heat transfer by radiation and convection were calculated based on the energy balance model for two batches. The results indicate that the Joule heating effect is a very effective and prospective way of enhancing the electrical and thermal stability of epoxy–CB composites for consumer use as heaters and in other electronic areas such as electromagnetic shielding effectiveness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 97–109, 2003     

The Effects of Synthetic Oligopeptide Derived from Enamel Matrix Derivative on Cell Proliferation and Osteoblastic Differentiation of Human Mesenchymal Stem Cells

Enamel matrix derivative (EMD) is widely used in periodontal tissue regeneration therapy. However, because the bioactivity of EMD varies from batch to batch, and the use of a synthetic peptide could avoid use from an animal source, a completely synthetic peptide (SP) containing the active component of EMD would be useful. In this study an oligopeptide synthesized derived from EMD was evaluated for whether it contributes to periodontal tissue regeneration. We investigated the effects of the SP on cell proliferation and osteoblast differentiation of human mesenchymal stem cells (MSCs), which are involved in tissue regeneration. MSCs were treated with SP (0 to 1000 ng/mL), to determine the optimal concentration. We examined the effects of SP on cell proliferation and osteoblastic differentiation indicators such as alkaline phosphatase activity, the production of procollagen type 1 C-peptide and osteocalcin, and on mineralization. Additionally, we investigated the role of extracellular signal-related kinases (ERK) in cell proliferation and osteoblastic differentiation induced by SP. Our results suggest that SP promotes these processes in human MSCs, and that ERK inhibitors suppress these effects. In conclusion, SP promotes cell proliferation and osteoblastic differentiation of human MSCs, probably through the ERK pathway.     

Production of 8,11,14,17-cis-eicosatetraenoic acid by Δ5 desaturase-defective mutants of an arachidonic acid-producing fungus, Mortierella alpina

Δ5 Desaturase-defective mutants of an arachidonic acid-producing fungus, Mortierella alpina 1S-4, accumulate large amounts of 8,11,14,17-cis-eicosatetraenoic acid (20:4ω3) when grown with linseed oil. One of the mutants, the S14 strain, produced 1.65 mg of 20:4ω3 per mL of culture medium (corresponding to 66.0 mg/g dry mycelia and 11.6% of total cellular fatty acids) when grown in a medium containing 1% glucose, 1% yeast extract, and 4% linseed oil methyl ester at 28°C for 2 d, and then at 16°C for 7 d. In a bench-scale fermentation in a 5-L jar fermenter, 20:4ω3 production reached 1.60 g/L of culture medium on the eighth day (corresponding to 77.3 mg/g dry mycelia and 26.0% of total cellular fatty acids). The cellular lipids of the S14 strain comprised 75.8% triacylglycerol (TG), 6.7% diacylglycerol, and 13.3% phospholipids (PL). The percentage of 20:4ω3 was higher in PL than in TG, and highest in phosphatidylcholine (32.6%).     

Production of 8,11,14,17-cis-eicosatetraenoic acid (20:4ω-3) by a Δ5 and Δ12 desaturase-defective mutant of an arachidonic acid-producing fungus Mortierella alpina 1S-4

A Δ5 and Δ12 desaturase-defective mutant of an arachidonic acid-producing fungus, Mortierella alpina 1S-4, produced 8,11,14,17-cis-eicosatetraenoic acid (20:4ω3) intracellularly when grown with linseed oil. Dihomo-γ-linolenic acid was the only C₂₀ polyunsaturated fatty acid (4.9 wt% of total mycelial fatty acids) other than 20:4ω3. AA and 5,8,11,14,17-cis-eicosapentaenoic acid were not detected. The mycelial lipids consisted of 82.2% (by mol) triacylglycerol (TG), 7.1% diacylglycerol, 8.9% phospholipids (PL), and 1.9% free fatty acids. The percentage of 20:4ω3 was higher in PL (30.1%) than in TG (11.6%), and highest in phosphatidylcholine (38.9%). Under the optimal conditions with a 5-L jar fermenter, 20:4ω3 production amounted to 97.4 mg/g dry mycelia with a mycelial yield of 23 g/L on the twelfth day (corresponding to 2.24 g/L medium and 37.1% of total mycelial fatty acids).     

A molecular dynamics study on liquid-vapor interface adsorbed by impurities

In this paper, we focus on the microscopic structure of the liquid-vapor interface and the effect of impurities such as surfactants or electrolytes in the aqueous solution on interfacial properties. We perform molecular dynamics (MD) simulations of a simple planar interface system and a bubble system in which a nanometer-size void region is maintained. In these MD systems, some static and dynamic properties of molecules near the interface are investigated and we elucidate some microscopic features of the interface. Especially, we show the difference of the dynamics of water molecules between the surfactant and electrolyte solutions. We also consider the definition of the interface at the molecular level which can treat the local and instantaneous structure, and discuss the physical properties which we calculate including the effect of molecular fluctuations of the interface.     

Low-power video encoder/decoder chip set for digital VCRs

This paper describes the realization of a video encoder/decoder chip set for the consumer use digital video cassette recorder (VCR). The two chips with a 5 Mb external DRAM either encode the CCIR601 digital component video signal into the standard-definition digital VCR (DV) format or decode the DV format signal into a component video signal. The compression rate of the intraframe compression is about 1/6. The total power dissipation of the two LSI's is 142 mW at 2 V internal supply voltage, which is more than one order of magnitude smaller than the recently reported MPIEG2 (MP@ML) encoder systems. Low power was achieved primarily due to the compression scheme which is optimized for large-scale integration (LSI) implementation. The 0.5-μm 2-V CMOS standard cell library was also effective in reducing the power consumption. Each chip, fabricated in two-layer metal 0.5-μm CMOS technology, contains about 500 k transistors on 71 mm² and 79 mm² die, respectively     

Increased anxiety-like behavior in neuropsin (kallikrein-related peptidase 8) gene-deficient mice.

Neuropsin (kallikrein-related peptidase 8) is concentrated in the hippocampus, amygdala, olfactory bulb, and prefrontal cortex. Earlier studies showed that protease deficiency causes a significant impairment of early-phase long-term potentiation in the Schaffer collateral pathway and hippocampus-dependent memory in the Y maze and Morris water maze (Z. Chen et al., 1995; A. Hirata et al., 2001; H. Tamura et al., 2006). In addition to neuropsin's participation in the hippocampal memory, amygdalar and cortical localization of the gene suggests extrahippocampal behavioral function, and the authors therefore examined neuropsin-deficient mice, including tests of sensory motor reflex, open field, light-dark transition, Rota-Rod, elevated plus-maze, hot plate, startle response-prepulse inhibition, Porsolt forced swim, Barnes maze, eight-arm radial maze, and contextual and cued fear conditioning tests. Here, the authors found increased anxiety in neuropsin-deficient mice, suggesting the involvement of this protease in emotional responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emergence of karyotypically unrelated clone in remission of de novo acute myeloblastic leukaemias

The creation of effective cancer units is central to the implementation of the report A Policy Framework for Commissioning Cancer Services, produced by the Chief Medical Officers of England and Wales, recently issued by the Department of Health in April 1995. While cancer units are described in this report a range of important questions remain about their nature and how they should be developed. This paper addresses these issues in three ways. A definition of the cancer unit is suggested and its main implications spelt out. The problems of establishing cancer units are covered under three headings. Where should cancer units be? Which cancer sites should the unit cover? What is needed to establish the cancer unit? Finally two checklists are presented, describing the task from the perspectives of the district health authority and hospital(s) concerned. The underlying theme is that real changes in clinical practice and organisation are the goal, and these can only be achieved where there is extensive local dialogue in which the relevant issues are addressed in a structured and rigorous manner. Cosmetic changes in hospital designation will not achieve the consistent quality of cancer service that is the cornerstone of the 'Calman' policy.