Micro pixel chambers (
μ
-PIC) are gaseous two-dimensional imaging detectors originally manufactured using printed circuit board (PCB) technology. They are used in MeV gamma-ray astronomy, ...medicalimaging, neutron imaging, the search for dark matter, and dose monitoring. The position resolution of the present
μ
-PIC is approximately 120
μ
m (RMS), however some applications require a fine position resolution of less than 100
μ
m. To this end, we have started to develop a
μ
-PIC based on micro electro mechanical system (MEMS) technology, which provides better manufacturing accuracy than PCB technology. Our simulation predicted the gains of MEMS
μ
-PICs to be twice those of PCB
μ
-PICs at the same anode voltage. We manufactured two MEMS
μ
-PICs and tested them to study their behavior. In these experiments, we successfully operated the fabricatedMEMS
μ
-PICs and we achieved a maximum gain of approximately 7×10
3
and collected their energy spectra under irradiation of X-rays from
55
Fe. However, the measured gains of the MEMS
μ
-PICs were less than half of the values predicted in the simulations. We postulated that the gains of the MEMS
μ
-PICs are diminished by the effect of the silicon used as a semiconducting substrate.
We propose a novel optical orthogonal frequency-division multiplexing (OFDM) transmission, where the frequency spacing of subchannels is less than the symbol rate. We show experimentally that the ...novel OFDM transmission achieves an optical SNR (OSNR) sensitivity level and dispersion tolerance roughly equivalent to those of the conventional OFDM. We also show the influence of chromatic dispersion from the transmission channel on the OFDM signal. The chromatic dispersion causes a desynchronization of the symbol timing between subchannels and breaks the frequency orthogonality in OFDM. We confirm experimentally that it is possible to mitigate the signal degradation due to the chromatic dispersion by optimizing the symbol timing and orthogonally polarizing the subchannels to the neighboring subchannels.
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•Bloodstain stored at below −20°C was suitable for detecting mRNA.•Even if blood was stored at below −20°C, it wasn’t suitable for detecting mRNA.•Bloodstain stored at below −20°C was ...suitable for STR typing.
The effects of various storage conditions on blood identification tests, DNA degradation, and short tandem repeat (STR) typing were evaluated. Bloodstains stored at room temperature, 4°C, −20°C, and −80°C for 20years; blood samples stored at −20°C and −80°C for 20years; and fresh blood samples were analyzed. Leuco-malachite-green testing, anti-human hemoglobin (Hb) testing (using immunochromatography), and tests for hemoglobin-beta (HBB) mRNA were performed as blood identification tests. DNA degradation was evaluated by quantifying the ratios of 305 and 129 base pair (bp) fragments to 41bp fragments. STR typing was performed using an AmpFlSTR® Identifiler™ Plus PCR Amplification Kit. All samples were positive in leuco-malachite-green staining and anti-human Hb assays. HBB was not detected in blood samples stored at −20°C or −80°C, although this marker was detected in all bloodstains. As indicated by the ratio of 129:41bp and 305:41bp DNA fragments, DNA from bloodstains stored at room temperature or 4°C were significantly degraded compared to DNA from all other samples. STR typing analyses revealed that a portion of the loci was undetected in bloodstains stored at room temperature. Therefore, to prevent DNA degradation during long-term storage, it is recommended that bloodstains and blood be stored at below −20°C. In addition, because bloodstains are more suitable for detection of blood-specific mRNAs than blood sample, it is desirable that blood is stored as bloodstain for this method.
Changes in the sugar and amino acid contents of potato tubers during short-term storage and the effect on the acrylamide level in chips after frying were investigated. The acrylamide content in chips ...began to increase after 3 days of storage at 2 deg C in response to the increase of glucose and fructose contents in the tubers. There was strong correlation between the reducing sugar content and acrylamide level, R**2 = 0.873 for fructose and R**2 = 0.836 for glucose. The sucrose content had less correlation with the acrylamide content because of its decrease after 4 weeks of storage at 2 deg C, while the reducing sugar in potato tubers and the acrylamide in chips continued to increase. The contents of the four amino acids, i.e., asparatic acid, asparagine, glutamic acid and glutamine, showed no significant correlation with the acrylamide level. These results suggest that the content of reducing sugars in potato tubers determined the degree of acrylamide formation in chips. The chip color, as evaluated by L* (lightness), was correlated well with the acrylamide content.
An effective condition of graft polymerization of acrylonitrile onto cellulose fiber in large volume of KMnO₄/citric acid aqueous solution was examined and the produced grafted copolymers were ...characterized by using SEM, NMR, FTIR, XRD, TGA, and DSC in comparison with component homopolymers. Graft yield, GY, obtained by simple weighting method was close to the value obtained by NMR analysis. Significant change of chemical structure in cellulose fiber, other than graft reaction, was not detected by NMR and FTIR measurements, whereas a decrease in the degree of crystallinity by the reaction was detected by XRD measurement. It was pointed out that thermograms for grafted samples resembles with that of cellulose at T < 370°C and become similar with that for polyacrylonitrile at T > 370°C and the mass of residue at 550°C is proportional to the content of polyacrylonitrile (GY) only. It is concluded that thermal decomposition of both polymers occurs almost independently in grafted polymers and thermal stability of cellulose fiber is not improved.
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