40-Gbit/s TDM transmission technologies based on ultra-high-speedICs

This paper presents 40-Gbit/s time division multiplexing (TDM) transmission technologies based on 0.1-μm-gate-length InP high electron mobility transistor IC's and a scheme for upgrading toward a terabit-per-second capacity system. A 40-Gbit/s, 300-km, in-line transmission experiment and a dispersion-tolerant 40-Gbit/s duobinary transmission experiment are described as 40-Gbit/s single carrier system applications on dispersion-shifted fiber. An ultra-high-speed receiver configuration using a high-output-power photodiode is introduced to realize fully electrical receiver operation beyond 40 Gbit/s. The high-sensitivity operation of the optical receiver (-27.6 dBm@BER=10^-9) is demonstrated at a data bit rate of 50 Gbit/s for the first time using a unitraveling carrier photodiode. A dense wavelength division multiplexing (DWDM) system operating up to terabits per second can be easily realized on a zero-dispersion flattened transmission line using ultra-high speed TDM channels of 40 Gbit/s and beyond. An experiment demonstrates 1.04-Tbit/s DWDM transmission based on 40-Gbit/s TDM channels with high optical spectrum density (0.4 bit/s/Hz) without dispersion compensation     

Strigolactones Modulate Salicylic Acid-Mediated Disease Resistance in Arabidopsis thaliana

Strigolactones are low-molecular-weight phytohormones that play several roles in plants, such as regulation of shoot branching and interactions with arbuscular mycorrhizal fungi and parasitic weeds. Recently, strigolactones have been shown to be involved in plant responses to abiotic and biotic stress conditions. Herein, we analyzed the effects of strigolactones on systemic acquired resistance induced through salicylic acid-mediated signaling. We observed that the systemic acquired resistance inducer enhanced disease resistance in strigolactone-signaling and biosynthesis-deficient mutants. However, the amount of endogenous salicylic acid and the expression levels of salicylic acid-responsive genes were lower in strigolactone signaling-deficient max2 mutants than in wildtype plants. In both the wildtype and strigolactone biosynthesis-deficient mutants, the strigolactone analog GR24 enhanced disease resistance, whereas treatment with a strigolactone biosynthesis inhibitor suppressed disease resistance in the wildtype. Before inoculation of wildtype plants with pathogenic bacteria, treatment with GR24 did not induce defense-related genes; however, salicylic acid-responsive defense genes were rapidly induced after pathogenic infection. These findings suggest that strigolactones have a priming effect on Arabidopsis thaliana by inducing salicylic acid-mediated disease resistance.     

Determination of back-pressure profile for forward extrusion using sequential approximate optimization

This paper proposes a method for determining optimal back-pressure profile in forging of aluminum alloy using a sequential approximate optimization (SAO). In forging, it is important to improve the mold filling for the product quality. In addition, it is preferable to produce a product with a minimum forming energy. To achieve these objectives simultaneously, a forging method with back-pressure profile is proposed. Here, the back-pressure profile implies that the back-pressure varies through the stroke. In this paper, a multi-objective optimization (MOO) problem is formulated. To improve the mold filling, an unfilled area is taken as the first objective function. Furthermore, a forming energy during the forging is taken as the second objective function. Numerical simulation in the forging is so expensive that the SAO using the radial basis function (RBF) network is adopted, and the pareto-frontier is identified with a small number of simulation runs. Based on the numerical result, the experiments are also conducted. It can be found from these results that, the back-pressure profile approach is valid for improving the mold filling as well as the forming energy.     

Decameric GTP cyclohydrolase I forms complexes with two pentameric GTP cyclohydrolase I feedback regulatory proteins in the presence of phenylalanine or of a combination of tetrahydrobiopterin and GTP

The activity of GTP cyclohydrolase I is inhibited by (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (BH4) and stimulated by phenylalanine through complex formation with GTP cyclohydrolase I feedback regulatory protein (GFRP). Gel filtration experiments as well as enzyme activity measurements showed that the number of subunits of GFRP in both the inhibitory and stimulatory complexes is equal to that of GTP cyclohydrolase I. Because GFRP is a pentamer and GTP cyclohydrolase I was shown here by cross-linking experiments to be a decamer, the results indicate that two molecules of a pentameric GFRP associate with one molecule of GTP cyclohydrolase I. Gel filtration analysis suggested that the complex has a radius of gyration similar to that of the enzyme itself. These observations support our model that one molecule of GFRP binds to each of the two outer faces of the torus-shaped GTP cyclohydrolase I. For formation of the inhibitory protein complex, both BH4 and GTP were required; the median effective concentrations of BH4 and GTP were 2 and 26 microM, respectively. BH4 was the most potent of biopterins with different oxidative states. Among GTP analogues, dGTP as well as guanosine 5'-O-(3'-thiotriphosphate) exhibited similar inducibility compared with GTP, whereas other nucleotide triphosphates had no effect. On the other hand, phenylalanine alone was enough for formation of the stimulatory protein complex, and positive cooperativity was found for the phenylalanine-induced protein complex formation. Phenylalanine was the most potent of the aromatic amino acids.     

Poly(thioether imide)s via chloro-displacement polymerization

Summary Thioether containing polyimides were prepared by displacement of chlorine groups from substituted imides by aromatic and aliphatic sulfur nucleophiles. The allaromatic monomers and polymers had poor solubility which led to precipitation during synthesis and low molecular weight polymers. However, these polymers were thermally stable up to 400 °C and had T_g's ranging from 212 °C to 233 °C. Poly(thioether imide)s prepared from 1,3-propanedithiol and 2-mercaptoethyl sulfide had good solubility but lower thermal stability, showing TGA loss onset temperatures of 297 °C and 298 °C, respectively.     

A 40-Gbit/s superdynamic decision IC fabricated with 0.12-μmGaAs MESFET's

This paper describes a 4O-Gbit/s decision integrated circuit (IC) fabricated with 0.12-μm gate length GaAs metal-semiconductor field-effect transistors (MESFET's). A superdynamic flip-flop circuit and a wide-band amplifier were applied in order to attain 40-Gbit/s operation. A conventional static decision IC was also fabricated for comparison. The dynamic decision IC operated up to 40 Gbit/s, which is twice as fast as the conventional static decision IC. Error-free 40-Gbit/s operation is the fastest among GaAs MESFET decision IC's     

Numerical simulation of recorded bit in magneto-optical mediahaving thermally different protective layers

The influence of the thermal properties of the media in a multilayered magnetooptical disk on thermomagnetic recording characteristics such as recorded bit size and sensitivity has been investigated. Thermal properties have been simulated using several different dielectrics and metals for both undercoat and overcoat layers. Media with oxide layers represent those having low thermal diffusivity and large heat capacity, whereas nitride layers represent those with high thermal diffusivity and small heat capacity. Small domains are formed when an Al layer covers a Ta₂O₅ overcoat. Both recording sensitivity and bit-size increase for media with nitride layers compared with those having an Al top coat. When the same recording power is applied, media with oxide layers provide the most sensitive disks with the largest recorded bit-size among the structures studied. The results are explained by the differences in the heat capacities of the media together with the differences between the vertical and lateral heat flow throughout the layered structure     

Prophylactic perioperative treatment in a patient with colon carcinoma complicated by polycythemia vera

A patient with colon carcinoma complicated by polycythemia vera (PV) who underwent a partial colectomy concomitant with prophylactic perioperative treatment resulting in successful outcome is herein described. Seven weeks after the cessation of the latest exacerbation of PV, a partial colectomy was performed. In order to prevent the development of disseminated intravascular coagulation and thrombotic complications, the following perioperative treatment was performed: administration of gabexate mesilate (2,000 mg/day), fresh frozen plasma (300 ml/day), heparin (5,000 IU/day) for 7 days and anti-thrombin-III for 4 days, and a potent antibiotic therapy for 12 days and graded elastic bandages around the bilateral lower extremities for 14 days. As a result, an uneventful postoperative course was achieved. The present case suggests that these treatments are useful in the perioperative management of PV patients.     

Periodic metal plate-loaded dielectric slab antenna with broadsideradiation

Wave guiding properties of a periodic metal plate-loaded dielectric slab structure are investigated for obtaining surface wave antennas with broadside radiation and low voltage standing wave ratio (VSWR) characteristics. A novel technique is proposed in which dielectric phase transformers play an essential role for realizing a uniform phase distribution on the radiating aperture which is required to achieve broadside radiation. A quarter-guided wavelength spacing of the metal plates guarantees the suppression of reflections at the input port. On the basis of the theoretical results obtained, two types of antennas have been designed at 10 GHz, one having the exponential aperture distribution, the other the uniform aperture distribution. The overall antenna efficiency of the latter type has been found to be 53%, exhibiting a practical performance at microwave frequencies