Preparation of long sticky ends for universal ligation-independent cloning: Sequential T4 DNA polymerase treatments

Ligation-independent cloning (LIC) is a useful method for efficient directional cloning of a PCR product. LIC requires a specially designed vector containing a long stretch of sequence that is missing any one of the four nucleotides. When the linearized vector is treated with T4 DNA polymerase, in the presence of the absent base, long single-stranded overhangs are generated that are suitable for cloning. In this study, long and efficient sticky ends for LIC were produced by sequential T4 DNA polymerase treatments at non-specific sequences on a commercially available vector. All restriction enzyme sites become available in the current LIC.     

A systematic design formulation for Butler matrix applied FFT algorithm

A systematic general design formulation for a Butler matrix (Bmatrix) is described. TheBmatrix design problem discussed is used to determine phase shift location and value in a matrix, when the number of beam (elements of array)M = 2^{N}and the scattering matrix for the hybrid couplers are specified. The design formulation presented is based on the fact that aBmatrix design procedure and an FFT algorithm are equivalent in fundamental concepts. It is shown that theBmatrix design procedure can be systematically formulated by the FFT algorithm modifications, which preserves the topological properties of the original signal flow diagram. A simple design formula has been established by this formulation.     

New switched-capacitor immittance converter using operational amplifier leapfrog structure

A new switched-capacitor immittance converter is obtained from the operational amplifier leapfrog structure which simulates a grounded inductor. Any capacitive (n + 1)-terminal network which has a capacitance matrix can be converted into the corresponding inductive network by using a set of these n immittance converters.     

A 16-Mbit DRAM with a relaxed sense-amplifier-pitch open-bit-linearchitecture

A 16-Mb dynamic RAM has been designed and fabricated using 0.5-μm CMOS technology with double-level metallization. It uses a novel trench-type surrounding high-capacitance cell (SCC) that measures only 3.3-μm² in cell size with a 63-fF storage capacitance. A novel relaxed sense-amplifier-pitch (RSAP) open-bit-line architecture used on the DRAM achieves a high-density memory cell array, while maintaining a large enough layout pitch for the sense amplifier. These concepts allow the small chip that measures 5.4×17.38 (93.85) mm² to be mounted in a 300-mil dual-in-line package with 65-ns RAS access time and 35-ns column address access time     

Involvement of heat shock protein 90 in the degradation of mutant insulin receptors by the proteasome

We previously reported three families with type A insulin-resistant syndrome who had mutations, either Asp1179 or Leu1193, in the kinase domain of the insulin receptor. The extreme insulin resistance of these patients was found to be caused by the decreased number of insulin receptors on the cell surface, due to the intracellular rapid degradation (Imamura, T., Takata, Y., Sasaoka, T., Takada, Y., Morioka, H., Haruta, T., Sawa, T., Iwanishi, M., Yang, G. H., Suzuki, Y., Hamada, J., and Kobayashi, M. (1994) J. Biol. Chem. 269, 31019-31027). In the present study, we first examined whether these mutations caused rapid degradation of unprocessed proreceptors, using the exon 13 deleted mutant insulin receptors (DeltaEx13-IR), which were accumulated in the endoplasmic reticulum as unprocessed proreceptors. The addition of Asp1179 or Leu1193 mutation to DeltaEx13-IR caused accelerated degradation of the unprocessed DeltaEx13-IR in the transfected COS-7 cells. Next, we tested whether these mutant receptors were degraded by the proteasome. Treatment with proteasome inhibitors Z-Leu-Leu-Nva-H (MG-115) or Z-Leu-Leu-Leu-H (MG-132) prevented the accelerated degradation of these mutant receptors, resulting in increased amounts of the mutant receptors in the COS-7 cells. Essentially the same results were obtained in the patient's transformed lymphocytes. Finally, we found that these mutant receptors bound to heat shock protein 90 (Hsp90). To determine whether Hsp90 played an important role in the accelerated receptor degradation, we examined the effect of anti-Hsp90 antibody on the mutant receptor degradation. The microinjection of anti-Hsp90 antibody into cells prevented the accelerated degradation of both Asp1179 and Leu1193 mutant insulin receptors. Taken together, these results suggest that Hsp90 is involved in dislocation of the mutant insulin receptors out of the endoplasmic reticulum into the cytosol, where the mutant receptors are degraded by the proteasome.     

Formation of monodisperse lead aerosols and identification of particle number concentration by ice nucleation

Lead aerosols were generated to investigate the conditions for the formation of monodisperse aerosols in nitrogen stream. Aerosols of high monodispersity could be obtained by vaporizing lead at a temperature in the range of 1000° to 1150°C and by flowing nitrogen at a rte of 1.5 l/min.In order to produce “lead iodide aerosols” portions of the lead aerosols were conducted into a test chamber in which the atmosphere of iodine vapor had previously been prepared. This mixture containing the aerosols with low concentration was moderately stirred under different temperatures.“The lead iodide aerosols” were sampled with a syringe to be injected into a modified Bigg's test device for ice nucleation. The aerosols injected rapidly changed into ice crystals, which could grow in size. As the number of ice crystals could give that of lead iodide aerosols, the reactivity of lead aerosols with iodine vapor was investigated under various temperatures. An increase in temperature during the ageing of lead aerosols with iodine vapor promoted their reactivity.     

0.81 ?m band AlGaAs/GaAs double-channel planar buried-heterostructure laser with large optical cavity

0.81 ?m-band AlGaAs/GaAs double-channel planar buried-heterostructure laser diodes with large optical cavity have been developed as light sources for use in analogue optical fibre communication systems. Linear light-output/current characteristics and a single-longitudinal-mode spectrum at a modulation frequency f = 100 MHz with modulation index m = 0.9 have been attained.     

Insolubilization mechanism and lithographic characteristics of a negative electron beam resist iodinated polystyrene

To elucidate the insolubilization mechanism of iodinated polystyrene (IPS) upon exposure to an electron beam and deep UV, the effects of additives on exposure characteristics of IPS and its parent polymer, polystyrene, are clarified. Results indicate the following mechanism. Iodine atoms produced by homolytic dissociation upon exposure undergo competitive reactions: the radical recombination which is the reverse of dissociation and the formation of other radicals that leads to insolubilization. The proposed reaction mechanism can explain the relationship between the sensitivity and degree of iodination. The G values for crosslinking of IPS, G(X), are also obtained according to Charlesby's theory. The calculated lithographic characteristics on the basis of G(X) are discussed.     

Stable transverse mode oscillation in planar stripe laser with deep Zn diffusion

The guiding mechanism in a planar stripe laser with deep Zn diffusion under the lasing conditions was investigated both theoretically and experimentally. The conditions necessary to realize refractive index guiding depend on a combination of electron and hole concentrations. The lasers under refractive index guiding, whose stripe width is less than twice the diffusion length, with an adequate combination of electron and hole concentrations, show stable fundamental transverse mode oscillation up to three times the threshold current level.