Magnetic record support

The magnetic layer of a magnetic record support is coated with a thin film of a polymer with a siloxane bond. The magnetic layer consists of a thin film obtained by vacuum metallization, cathode sputtering or dispersion of a ferromagnetic metal powder in a binder. The polymer with a siloxane bond is produced by the polymerization of an organic silicon compound which inherently contains or is able to form this bond. Polymerization is preferably performed by plasma polymerization

Development of a liquid scintillator containing a zirconium β-keto ester complex for the ZICOS experiment

AbstractA liquid scintillator containing a zirconium β-keto ester complex has been developed for the ZIrconium Complex in Organic Scintillator (ZICOS) neutrinoless double beta decay experiment. We are aiming to develop a detector which has a good energy resolution (4% at 2.5 MeV), a large light yield (60% that of BC505) and a low background rate (0.1 counts/tonne⋅year) with several tonnes of 96Zr isotope, so we have investigated the zirconium β-keto ester complexes tetrakis(isopropyl acetoacetato)zirconium and tetrakis(ethyl acetoacetato)zirconium, which have high solubility (over 10 wt.%) in anisole. We measured the performance of liquid scintillators containing these zirconium β-keto ester complexes and obtained 40% of the light yield of BC505 and energy resolution of 4.1% at 2.5 MeV assuming 40% photo coverage of the photomultiplier in the ZICOS detector. Thus we almost achieved our initial goal. Preliminary investigations indicate that tetrakis(diethyl malonato)zirconium will give us no quenching of the light yield and an energy resolution of 2.9% at 2.5 MeV. This will be a suitable complex for the ZICOS experiment, if it has a large solubility

Development of Liquid Scintillator containing a Zirconium Complex for Neutrinoless Double Beta Decay Experiment

An organic liquid scintillator containing a zirconium complex has been developed for a new neutrinoless double beta decay experiment. In order to produce a detector that has good energy resolution (4% at 2.5 MeV) and low background (0.1 counts/(tonne・year) and that can monitor tonnes of target isotope, we chose a zirconium β-diketone complex having high solubility (over 10 wt.%) in anisole. However, the absorption peak of the diketone ligand overlaps with the luminescence of anisole. Therefore, the light yield of the liquid scintillator decreases in proportion to the concentration of the complex. To avoid this problem, we synthesized a β-keto ester complex introducing -OC3H7 or -OC2H5 substituent groups in the β-diketone ligand, and a diethyl malonate complex. Those shifted the absorption peak to around 245nm and 210nm, respectively, which are shorter than the emission peak of anisole (275nm). However, the shift of the absorption peak depends on the the scintillation solvent. Therefore we have to choose an adequate solvent for the liquid scintillator. The best performance will be obtained by pure anisole scintillator containing a tetrakis diethyl malonate zirconium. We also synthesized a Zr-ODZ complex, which has a high quantum yield (30%) and good emission wavelength (425nm) with a solubility 5 wt.% in benzonitrile. However, the absorption peak of the Zr-ODZ complex was around 240 nm. Therefore, it is better to use the scintillation solvent which has shorter luminescence wavelength than that of benzonitrile

Seasonal variations of atmospheric C2-C7 nonmethane hydrocarbons in Tokyo

Eighteen C2-C7 NMHCs (nonmethane hydrocarbons) were measured hourly during the Integrated Measurement Program for Aerosol and Oxidant Chemistry in Tokyo (IMPACT) measurement campaigns conducted in central Tokyo during four different periods (summer/autumn of 2003 and winter/summer of 2004). The ambient atmospheric concentrations of NMHCs showed an inverse correlation with wind speed and mixing height and were significantly affected by mesoscale weather conditions. The mixing ratio of isoprene tightly correlated with solar flux and temperature in summer, as it was dominantly emitted by the local vegetation. All the observed NMHCs except isoprene showed high correlation with each other in winter (r2 > 0.5), suggesting concurrent accumulation under stagnant condition and common sources. Emission ratios were calculated on the basis of the correlation with carbon monoxide and ethyne. Compared to the typical winter NMEC composition, during summer there was a significant increase (up to 7 times higher than wintertime) of C4-C5 alkanes from ftiel evaporation; of C2-C3 alkenes, n-hexane and benzene from chemical industry; and of toluene from local manufacturers, reflecting the temperature dependence of these evaporative emissions. In addition to the online measurements in Tokyo, canister sampling at a suburban site (Kisai) followed by multidimensional GC analyses was conducted during the summer campaign in 2004. The atmospheric concentrations of longer-lived compounds (≥ several days) at Kisai showed the buildup under sea breeze circulation. The average ambient, concentration of toluene was 2 times higher than that in central Tokyo, likely because of substantial emissions from local industries as reported in the prefectural statistics. Copyright 2007 by the American Geophysical Union

Performance of a liquid scintillator containing a zirconium β-keto ester complex developed for the ZICOS experiment

A liquid scintillator containing a zirconium β-keto ester complex has been developed for the ZIrconium Complex in Organic Scintillator (ZICOS) neutrinoless double beta decay experiment. We are aiming to develop a detector which has a good energy resolution (4% at 2.5 MeV), a large light yield (60% that of BC505) and a low background rate (0.1 counts/tonne・year) with several tonnes of 96Zr isotope, so we have investigated the zirconium β-keto ester complexes tetrakis (isopropyl acetoacetato) zirconium and tetrakis (ethyl acetoacetato) zirconium, which have high solubility (over 10 wt.%) in anisole. We measured the performance of liquid scintillators containing these zirconium β-keto ester complexes and obtained 40% of the light yield of BC505 and energy resolution of 4.1% at 2.5 MeV assuming 40% photo coverage of the photomultiplier in the ZICOS detector. Thus we almost achieved our initial goal. Preliminary investigations indicate that tetrakis (diethyl malonato) zirconium will give us no quenching of the light yield and an energy resolution of 2.9% at 2.5 MeV. This will be a suitable complex for the ZICOS experiment, if it has a large solubility

Discrimination of Cherenkov light in Liquid Scintillator for Neutrinoless Double Beta Decay Experiment

　A liquid scintillator containing a tetrakis（isopropyl acetoacetato）zirconium has been developed for ZICOS experiment. We will use 180 tons of liquid scintillator containing 75 kg of 96Zr in the inner balloon（45 kg in fiducial volume）surrounding 64 % photo coverage of 20 inch photomultiplier. In order to reach the sensitivity ≥1027 years, we have to reduce 95 % of 208Tl decay backgrounds at least. Using Monte Carlo simulation, we could demonstrate new method using the hit pattern of PMT which received Cherenkov light, and could reduce 93 % of 208Tl background with 78 % efficiency for 0νββ signal. For the discrimination of Cherenkov light, we measured the timing pulse shape of Zr loaded liquid scintillator using FADC digitizer, and we found an inconsistent pulse shape at the rise timing with the template of scintillation. Also the event with an inconsistent pulse shape seems to have a directionality

Quantitative Virion Maturation Fluorescence Microscopy

HIV-1 infectivity is achieved through virion maturation. Virus particles undergo structural changes via cleavage of the Gag polyprotein mediated by the viral protease, causing the transition from an uninfectious to an infectious status. The majority of proviruses in people living with HIV-1 treated with combination antiretroviral therapy are defective with large internal deletions. Defective proviral DNA frequently preserves intact sequences capable of expressing viral structural proteins to form virus-like particles whose maturation status is an important factor for chronic antigen-mediated immune stimulation and inflammation. Thus, novel methods to study the maturation capability of defective virus particles are needed to characterize their immunogenicity. To build a quantitative tool to study virion maturation in vitro, we developed a novel single virion visualization technique based on fluorescence resonance energy transfer (FRET). We inserted an optimized intramolecular CFP-YPF FRET donor-acceptor pair bridged with an HIV-1 protease cleavage sequence between the Gag MA-CA domains. This system allowed us to microscopically distinguish mature and immature virions via their FRET signal when the FRET donor and acceptor proteins were separated by the viral protease during maturation. We found that approximately 80% of the FRET labeled virus particles were mature with equivalent infectivity to wild type. The proportion of immature virions was increased by treatment of virus producer cells with a protease inhibitor in a dose-dependent manner, which corresponded to a relative decrease in infectivity. Potential areas of application for this tool are assessing maturation efficiency in different cell type settings of intact or deficient proviral DNA integrated cells. We believe that this FRET-based single-virion imaging platform will facilitate estimating the impact on the immune system of both extracellular intact and defective viruses by quantifying the Gag maturation status