A CMOS multichannel 10-Gb/s transceiver

We describe a CMOS multichannel transceiver that transmits and receives 10 Gb/s per channel over balanced copper media. The transceiver consists of two identical 10-Gb/s modules. Each module operates off a single 1.2-V supply and has a single 5-GHz phase-locked loop to supply a reference clock to two transmitter (Tx) channels and two receiver (Rx) channels. To track the input-signal phase, the Rx channel has a clock recovery unit (CRU), which uses a phase-interpolator-based timing generator and digital loop filter. The CRU can adjust the recovered clock phase with a resolution of 1.56 ps. Two sets of two-channel transceiver units were fabricated in 0.11-/spl mu/m CMOS on a single test chip. The transceiver unit size was 1.6 mm /spl times/ 2.6 mm. The Rx sensitivity was 120-mVp-p differential with a 70-ps phase margin for a common-mode voltage ranging from 0.6 to 1.0 V. The evaluated jitter tolerance curve met the OC-192 specification.     

Eosinophil chemotaxis induced by several biologically active substances and the effects of apafant on it in vitro

Chemotaxis of guinea pig eosinophils induced by various stimuli in use of a modified Boyden chamber technique in vitro and the effect of a platelet-activating factor (PAF) antagonist, apafant (CAS 105219-56-5, WEB 2086 BS), on it were examined. The eosinophils were obtained by bronchoalveolar lavage from the animals treated by i.v. injection with Sephadex G-200 and purified by Percoll density gradient centrifugation. PAF significantly and potently induced the chemotaxis at a broad range of 10(-17) to 10(-7) mol/l, where no concentration-dependency was observed. Leukotriene B4 also induced the chemotaxis in a concentration-dependent manner at 10(-14) to 10(-12) mol/l and the enhanced migration was not declined until 10(-7) mol/l. Interleukin-5 (IL-5), IL-8 and regulated on activation normal T expressed and secreted (RANTES) only modestly enhanced the chemotaxis in some concentrations at 10(-13) to 10(-7) mol/l with or without significance and with no concentration-dependency while formyl-methionyl-leucyl-phenylalanine (FMLP), a known chemoattractant, increased the migration at 10(-7) to 10(-5) mol/l. Apafant at 10(-8) to 10(-6) mol/l strongly and concentration-dependently inhibited 10(-8) mol/l PAF-induced chemotaxis. However, the drug showed nominal or no influences on their chemotaxis stimulated by the other agonists, at the concentrations of which the enhanced migration was observed. From these results, it is concluded that IL-5, IL-8 and RANTES, different from PAF and LTB4, are not potent stimuli for the eosinophil chemotaxis and that apafant is a selective antagonist of PAF, which is expected to be therapeutically effective for PAF-associated diseases including bronchial asthma.     

KGa-priderite and related compound for the selective reduction of nitrogen monoxide with propylene

The catalytic activity of KGa-priderite, K_1.6Ga_1.6Ti_6.4O₁₆, and its related compound KGa₈Ga₉Ti₁₅O₅₆ was investigated for the selective reduction of nitrogen monoxide (NO) with propylene (C₃H₆) in the presence of high oxygen concentrations. The KGa-priderite showed significant activity during this reaction, but the related compound showed only a little activity. These compounds are quite different from the conventional catalysts for NO_x selective reduction and are characterized by the fact that their properties are free from the effects of solid acidity and support metals. This difference was attributable to the NO desorption rate at the surface of these compounds. It has become clear that the KGa-priderite catalyst remarkably adsorbed NO, and it is suggested that the amount of NO adsorbed and the amount of catalytic activity are able to be increased by the design of priderite structure.     

Physical and functional association of cortactin with Syk in human leukemic cell line K562

Human leukemic cell line K562 is induced to differentiate into the megakaryocytic lineage by stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA). We demonstrate here that TPA stimulation increases tyrosine phosphorylation of an 80-kDa protein at an early stage of megakaryocytic differentiation and that this 80-kDa protein is identical with cortactin. Since tyrosine kinase Syk was activated by TPA stimulation, we examined the possibility that cortactin is a potential substrate of Syk in K562 cells. TPA-induced tyrosine phosphorylation of cortactin was decreased profoundly by overexpression of dominant-negative Syk. Furthermore, cortactin was associated with Syk even before TPA stimulation. Since cortactin was previously referred as an 80/85-kilodalton pp60src substrate, we examined the association between Src and cortactin, whereas its association could not be detected. These data suggest that Syk phosphorylates cortactin in K562 cells upon TPA treatment.     

A broadband power meter calibration system in the frequency rangefrom 10 MHz to 40 GHz using a coaxial calorimeter

A broadband power meter calibration system based on a newly constructed coaxial calorimeter has been developed in the frequency region 10 MHz-40 GHz. The RF power is measured as the difference of DC power supplied to the calorimeter built-in heater in the RF load, when RF is turned off and on, holding an isothermal control between the RF load and a temperature reference. To minimize the error due to the adiabatic coaxial waveguide, we devised a new method utilizing its output port as a test port. The evaluations showed a calibration uncertainty of (0.28-2.2)% expressed by one standard deviation at the 1 mW level in the full band     

Generation of monoclonal antibodies to the rabbit interleukin-2 receptor alpha chain (CD25) and its distribution in HTLV-1-transformed rabbit T cells

Rabbits can be infected with human retroviruses such as human T-cell leukemia virus-1 (HTLV-1) and human immunodeficiency virus (HIV), and provide useful animal models to study retroviral diseases such as adult T-cell leukemia and HIV. Previously we have succeeded in generating monoclonal antibodies (mAbs) against rabbit CD4, CD5 and CD11a antigens. To make this animal species more amenable to cellular and molecular studies, we have attempted to extend the panel of mAbs against rabbit CD antigens. Here we report on the generation of three neutralizing mAbs against interleukin-2 receptor alpha chain (IL-2R alpha) (CD25), Kei-alpha 1 (IgG2b), Kei-alpha 2 (IgG2a) and Kei-alpha 3 (IgG1). They specifically recognize the rabbit Mr 55,000 IL-2 binding protein, IL-2R alpha, and completely inhibit both high- and low-affinity IL-2 binding to F648b cells that express IL-2R alpha as well as IL-2R beta. The use of mAb Kei-alpha 1 confirmed that the rabbit IL-2R alpha is not only a low-affinity IL-2R on its own but also an essential component of high-affinity IL-2R as found in other animal species, and that rabbit activated T cells including HTLV-1-transformed cell lines express high levels of the IL-2R alpha. Together with mAbs against various rabbit CD antigens that we reported previously, these neutralizing mAbs to IL-2R alpha will be valuable for studies of human retrovirus infections, such as those induced by HTLV-1 or HIV, in rabbits.     

Analysis of amyloid deposition in a transgenic mouse model of homozygous familial amyloidotic polyneuropathy

Amyloid fibrils derived from the Japanese, Portuguese, and Swedish types of familial amyloidotic polyneuropathy all consist of a variant transthyretin (TTR) with a substitution of methionine for valine at position 30 (TTR Met 30). In an attempt to establish an animal model of TTR Met-30-associated homozygous familial amyloidotic polyneuropathy and to study the structural and functional properties of human TTR Met 30, we generated a mouse line carrying a null mutation at the endogenous ttr locus (ttr-/-) and the human mutant ttr gene (6.0-hMet 30) as a transgene. In these mice, human TTR Met-30-derived amyloid deposits were first observed in the esophagus and stomach when the mice were 11 months of age. With advancing age, amyloid deposits extended to various other tissues. Because no significant difference was detected in the onset, progression, and tissue distribution of amyloid deposition between the ttr-/- and ttr+/+ transgenic mice expressing 6.0-hMet 30, endogenous normal mouse TTR probably does not affect the deposition of human TTR Met-30-derived amyloid in mice. TTR is a tetramer composed of four identical subunits that binds thyroxine (T4) and plasma retinol-binding protein. The introduction of 6.0-hMet 30 into the ttr-/- mice significantly increased their depressed serum levels of T4 and retinol-binding protein, suggesting that human TTR Met 30 binds T4 and retinol-binding protein in vivo. The T4-binding ability of human TTR Met 30 was confirmed by the analysis of T4-binding proteins in the sera of ttr-/- transgenic mice expressing 6.0-hMet 30. The T4-binding studies also demonstrated the presence of hybrid tetramers between mouse and human TTR subunits in the ttr+/+ transgenic mice expressing 6.0-hMet 30.     

Characteristics of a continuous Si-Ti-C-O fibre with low oxygen content using an organometallic polymer precursor

A continuous Si-Ti-C-O fibre with 12 wt% oxygen content, which is lower than the usual 18 wt% found in the normal fibres, was synthesized by using polytitanocarbosilane which has fewer Si-Si bonds than the usual precursor polymer. The density, tensile strength, tensile modulus and thermal conductivity were found to be 2.37 g cm^–3, 3.4±0.3 GPa, 190±10 GPa and 1.40 W m^–1 K^–1, respectively. Amongst these properties, the tensile modulus was improved by 20 GPa and the thermal conductivity had a higher value in comparison with that of the ordinary Si-Ti-C-O fibre with 18 wt% oxygen content. The Si-Ti-C-O fibre with a 12 wt% oxygen content has a better heat resistance above 1400 °C in an argon atmosphere and 1300 °C in air, than the usual fibre. About 60 and 40% of its tensile strength at room temperature were retained in air at respectively, 1500 and 1600 °C. This improved ceramic fibre is considered to be useful as a reinforcing material for advanced composites such as high-temperature ceramic matrix composites and metal matrix composites.