Kazutoshi Ito

Forward instrumentation for ILC detectors

Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10?3 and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised.

Purification and characterization of a raw starch-digestive amylase from non-sulfur purple photosynthetic bacterium

A strain of non-sulfur purple photosynthetic bacteria could utilize raw starch from corn, potato and cassava efficiently as a source of electron donor for hydrogen production. At least two amylases were found in the culture grown under light-anaerobic conditions with raw corn starch as a carbon source. These two amylases could digest raw starch as well as soluble starch. One of them was purified as a homogeneous protein with DEAE-cellulose column chromatography, ultra filtration with a membrane of Amicon XM 300, hydroxyapatite column chromatography, Toyopearl 55 HW gel filtration and starch gel affinity chromatography. The activity of this amylase was reactivated specifically by calcium ion after the enzyme was treated by EDTA. The optimum temperature of the enzyme activity was 40°C and the activity was stable up to 45°C. The optimum pH was 6.0 and the enzyme was quite stable at alkaline pH up to 12.0. This enzyme is an amylase that can digest raw starch from corn, potato and cassava.

Treatment of lipid-containing wastewater using bacteria which assimilate lipids

Abstract Bacteria which grew in a medium containing olive oil as a sole source of carbon were isolated from two meat plants in the Sendai district of Japan. All of the isolates tested assimilated beef tallow, lard, olive oil and used salad oil as a sole carbon source in shaking cultures. One of the isolates, strain 351, digested lipids most efficiently, as shown by the amount of n -hexane extracts that remained. This bacterium was identified as Bacillus sp. A new and efficient laboratory-scale apparatus for the biological treatment of lipid-containing wastewater was devised using strain 351. The apparatus consisted of a water circulation system for the primary treatment of the water, in which strain 351 was inoculated, and an ordinary aeration tank using activated sludge as a secondary treatment. Lipids in the wastewater could be almost completely removed by this apparatus without physical treatment. On the other hand, an ordinary aeration system in the laboratory using an air stone and air pump resulted in the floating of lipids, and was not successful in digesting lipids even in the presence of strain 351.

Cloning and expression of pectin lyase gene from Erwinia carotovora in Escherichia coli

A pectin lyase (PNL; EC 4.2.2.10) gene of Erwinia carotovora Er was cloned and expressed in Escherichia coli. The analysis of the nucleotide sequence of the 0.6 kb StuI-EcoRI fragment, which was hybridized with the mixed oligonucleotide probe for PNL gene, revealed the presence of an open reading frame (0RF) and correlated exactly with the known N-terminal 18 amino acid sequence of PNL. When a plasmid pTN2159, which has a BamHI-EcoRI fragment containing this ORF, was introduced into E. coli JM109, PNL was not expressed. When a tac-promoter was inserted in front of the ORF, PNL was efficiently expressed in E. coli. Synthesis of PNL by E. coli was also confirmed by immunoblot analysis.

Study of beam profile measurement at interaction point in international linear collider

Abstract At the international linear collider, measurement of the beam profile at the interaction point is a key issue to achieve high luminosity. We report a simulation study on a new beam profile monitor, called the pair monitor, which uses the hit distribution of the electron–positron pairs generated at the interaction point. We obtained measurement accuracies of 5.1%, 10.0%, and 4.0% for the horizontal ( σ x ) , vertical ( σ y ) , and longitudinal beam sizes ( σ z ) , respectively, for 50 bunch crossings.

Pixelated Readout Circuit for Pair-Monitor at International Linear Collider

The pair monitor measures the beam profile at the interaction point of the international linear collider. It extracts the information from the directional distribution of a large number of electron-positron pairs created by collision of bunches. The pairs are detected by pixel detectors placed close to the beam on both sides of the interaction point, and a readout ASIC that meets the stringent requirements has been developed. In order to measure the beam profile as a function of location within a train, and also to deal with the high hit rate, the pixel detector is read out in 16 time slices per bunch train. In this paper, we describe the design of the readout circuit and present the result of performance tests.

Cloning of two protease genes fromRhodocyclus gelatinosa APR 3-2 and their expression inEscherichia coli

Two different protease genes were cloned fromRhodocyclus gelatinosa APR 3-2 inEscherichia coli HB 101/λ with pBR329 or its derivatives. The recombinant plasmids designated as pRP100 and pRP300 contained 11.2 and 10.6 kb DNA fragments, respectively. The differences of both plasmids in restriction enzyme maps indicate that these plasmids contained different protease genes. DNA fragments coding for protease, 6.4 kb and 4.5 kb from pRP100 and pRP300, were subcloned into pRP329 and designated as pRP101 and pRP301, respectively. The two cloned proteases were excreted in culture medium ofE. coli, and ß-lactamase ofE. coli, which was originally localized in periplasmic space, was also excreted in the medium.

Pyocyanine as a potent inhibitor for the growth ofRhodopseudomonas sphaeroides B5

Pyocyanine seveely inhibited the growth ofRhodopseudomonas sphaeroides B5 under photosynthetic conditions. Under these conditions, pyocynine at concentrations of 0.05 and 0.1 μg/ml gave rise to about 61% and 99% inhibition, respectively, whereas pyocyanine at a concentration of 1 μg/ml was required to inhibit the growth by about 55% under aerobic dark conditions. Antibiotic action of pyocyanine under photosynthetic conditions was reveersible and not bactericidal. Degradation of carotenoid was observe in pyocyanine-treated cultures.