Sulfated Hyaluronan Binds to Heparanase and Blocks Its Enzymatic and Cellular Actions in Carcinoma Cells

We examined whether sulfated hyaluronan exerts inhibitory effects on enzymatic and biological actions of heparanase, a sole endo-beta-glucuronidase implicated in cancer malignancy and inflammation. Degradation of heparan sulfate by human and mouse heparanase was inhibited by sulfated hyaluronan. In particular, high-sulfated hyaluronan modified with approximately 2.5 sulfate groups per disaccharide unit effectively inhibited the enzymatic activity at a lower concentration than heparin. Human and mouse heparanase bound to immobilized sulfated hyaluronan. Invasion of heparanase-positive colon-26 cells and 4T1 cells under 3D culture conditions was significantly suppressed in the presence of high-sulfated hyaluronan. Heparanase-induced release of CCL2 from colon-26 cells was suppressed in the presence of sulfated hyaluronan via blocking of cell surface binding and subsequent intracellular NF-κB-dependent signaling. The inhibitory effect of sulfated hyaluronan is likely due to competitive binding to the heparanase molecule, which antagonizes the heparanase-substrate interaction. Fragment molecular orbital calculation revealed a strong binding of sulfated hyaluronan tetrasaccharide to the heparanase molecule based on electrostatic interactions, particularly characterized by interactions of (−1)- and (−2)-positioned sulfated sugar residues with basic amino acid residues composing the heparin-binding domain-1 of heparanase. These results propose a relevance for sulfated hyaluronan in the blocking of heparanase-mediated enzymatic and cellular actions.     

Mechanism of simultaneous tripping of ground directional relays in a 6.6‐kV distribution system

In Kyushu Electric Power's 6.6‐kV distribution system, after a single‐phase ground fault occurred in the circuit of a distribution line, we experienced a phenomenon in which the analogue ground directional relays of the other circuits linked to the same bank were simultaneously tripped. In this paper, focus is placed on the mechanism and possibility of simultaneous tripping of ground directional relays. This mechanism was examined in an experiment carried out using an analogue simulator. The results of the test revealed that such simultaneous tripping was attributable to the neutral instability phenomenon of grounding potential transformers installed in an isolated neutral system. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(2): 23–30, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20919     

Advances in Digital Front-End and Software RF Processing： Part II

In the first editorial of this two-part special issue, we pointed out that one of the biggest trends in wireless broadband, radar, sonar, and broadcasting technology is software RF processing and digital front-end [1]. This     

Arraying needle-like TiO2 particles in a composite film by applying ac bias and its transmittance anisotropy

In an effort to improve energy-efficient windows, we experimented with a precursor slurry composite by using needle-like TiO₂ particles as the filler in a urethane matrix. Applying dc bias to the slurry failed to array the needle-like particles in the composite and to deposit on the film surface because of electrophoretic movement. However, applying ac bias of ±5 V to the precursor slurry composite for 12 h resulted in the needle-like TiO₂ particles being arrayed in the composite in a direction normal to the film surface. This resulted in an improvement in the energy efficiency of the material through an angular dependence of transmittance in the visible–near-infrared range.     

GPC Profile Change of Potato Starch with Extrusion Processing

Native potato starch (moisture content 15%) was treated by twin screw extruder under four operating conditions with varying barrel temperatures (110°C–230°C). These modified starch samples were compared to native and drum-dried starch. Starch sample solution for gel chromatography was prepared by the three methods (acidic, alkaline, and neutral methods). They were subjected to gel chromatography on Toyopearl HW-75, and some difference was found among the three gel chromatographic patterns obtained from the same starch solution. This discrepancy among GPC patterns suggests formation of some types of anhydro-bonds between chains of amylopectin and or amylose in the extrusion process. Elevating barrel temperature increases degree of depolymerization. The size of fragments formed with the treatment is bigger than that of oligosaccharides but smaller than that of amylose.     

An optically clocked transistor array with dual serial-to-parallel and parallel-to-serial conversion capability for optical label swapping

We propose an optically clocked transistor array optoelectronic integrated circuit (OEIC) for both serial-to-parallel and parallel-to-serial conversion (demux/mux), enabling an interface between high-speed asynchronous burst optical labels and CMOS circuitry for optical label swapping. Dual functionality of the OEIC reduces size, power, and cost of the optical label swapper. The capability for greater than 20-Gb/s conversion operation is demonstrated.     

High-power mid-infrared wavelength generation using difference frequency generation in damage-resistant Zn:LiNb03 waveguide

High-power 3.4 mum difference frequency generation (DFG) using a quasi-phase-matched Zn:LiNbO₃ waveguide fabricated by direct bonding technology is presented. The high resistance of the waveguide to photorefractive damage allows high-power generation. A 65 mW mid-infrared output was obtained using a continuous-wave high- power fibre amplifier as pump source. The DFG source can access over 10 nm continuously simply by scanning the signal wavelength, and will be useful for real-time trace gas sensing.     

Scaling theory for double-gate SOI MOSFET's

A scaling theory for double-gate SOI MOSFETs, which gives guidance for device design (silicon thickness t_si; gate oxide thickness t_ox) that maintains a subthreshold factor for a given gate length is discussed. According to the theory, a device can be designed with a gate length of less than 0.1 μm while maintaining the ideal subthreshold factor. This is verified numerically with a two-dimensional device simulator     

The high-speed limit of FM response in semiconductor lasers

The high-speed frequency modulation (FM) response has been investigated through rate equation analysis. The intrinsic limit of FM response has been found to be given by the product of FM efficiency, η_FM, and the FM bandwidth, B. This relation shows that a wide FM bandwidth means a small FM efficiency. Although the FM efficiency changes with the differential gain or the nonlinear gain coefficient, η_FMB is almost constant. The value of η _FMB was about 5 GHz²/mA for 1.5-μm InGaAsP/InP lasers with 300-μm cavity length. This limit has been confirmed experimentally     

A 10-s doping technology for the application of low-temperaturepolysilicon TFTs to giant microelectronics

A bucket-type high-density (0.25-1.2-mA/cm²) low-energy (500-2000 V) ion source was utilized for high-speed phosphorus doping directly into a thin polysilicon layer without cap SiO₂. Doping gas with He dilution was selected to reduce etching of polysilicon film. Excimer laser (XeCl, 8 mm×8 mm) pulse annealing was introduced to activate effectively the doped impurity. The combination of these techniques provided a practically low sheet resistance for the TFT source, drain, and gate with a short time doping. The low-temperature polysilicon TFT fabricated with a doping time of 10 s had characteristics comparable to those of that fabricated by a longer time doping or conventional ion implantation, showing the practicality of this technology and its promise for giant microelectronics