Timing jitter removers of photon detectors

Among various performances of photon detectors, the timing jitter is difficult to improve because of its trade-offs with other important performances such as detection efficiency. Such trade-offs have been an issue in applications, especially for high-purity non-Gaussian-state generation necessary in optical quantum computation. Here, we introduce a method using an external fast optical switch -- Timing Jitter Remover (TJR) -- whose time window limits the photon-detectable time of photon detectors and improve the timing jitter without sacrificing other performances. By using a TJR, we experimentally improve the timing jitter of a photon-number-resolving detector based on a transition edge sensor, from 50 ns to 10 ns. Using this improved detector, we generate one of important non-Gaussian states, a Schr\"{o}dinger cat state with Wigner negativity of -0.01, which cannot be observed without TJRs. TJRs would be the key technology for the realization of ultra-fast, fault-tolerant, universal optical quantum computer.Comment: 26 pages, 6 figure

Effects of medium-chain triglycerides on gluconeogenesis and ureagenesis in weaned rats fed a high fat diet

We explored the effects of Medium-chain triglycerides (MCT) on gluconeogenesis and ureagenesis in the liver of weaned male rats fed high fat, carbohydrate-free diets. The rats of three experimental groups and control were fed for 10 days. The diets were high fat, carbohydrate-free diets consisting either of a corn oil or MCT, and high protein carbohydrate-free diet and a control (high carbohydrate) diet. The hepatic glucose-6-phosphatase (G6Pase) activity increased in the experimental groups. Despite the elevated G6Pase activity in these groups, hepatic activities of glutamic alanine transaminase (GAT), pyruvate carboxylase (PC) and arginase differed among the experimental groups. The HF-corn oil rats showed elevation of PC activity, but no elevation of GAT activity, and the lowest arginase activity among the three groups. The HF-MCT diet-fed rats showed higher GAT and arginase activities than the HF-corn oil group. In the HP diet-fed rats, GAT and arginase activities enhanced, PC did not

Structure elements can be predicted using the contact Volume among protein residues

Previously, the structure elements of dihydrofolate reductase (DHFR) were determined using comprehen­sive Ala-insertion mutation analysis, which is assumed to be a kind of protein “building blocks.” It is hypo­thesized that our comprehension of the structure elements could lead to understanding how an amino acid sequence dictates its tertiary structure. However, the comprehensive Ala-insertion mutation analysis is a time- and cost-consuming process and only a set of the DHFR structure elements have been reported so far. Therefore, developing a computational method to predict structure elements is an urgent necessity. We focused on intramolecular residue–residue contacts to predict the structure elements. We introduced a simple and effective parameter: the overlapped contact volume (CV) among the residues and calculated the CV along the DHFR sequence using the crystal structure. Our results indicate that the CV profile can recapitulate its precipitate ratio profile, which was used to define the structure elements in the Ala-insertion mutation analysis. The CV profile allowed us to predict structure elements like the experimentally determined structure elements. The strong correlation between the CV and precipitate ratio profiles indicates the importance of the intramolecular residue–residue contact in maintaining the tertiary structure. Additionally, the CVs between the structure elements are considerably more than those between a structure element and a linker or two linkers, indicating that the structure elements play a funda­mental role in increasing the intramolecular adhesion. Thus, we propose that the structure elements can be considered a type of “building blocks” that maintain and dictate the tertiary structures of proteins

ABROGATION OF THE G2/M ARREST ENHANCED THE CYTOTOXIC EFFECTS BY CARBON-ION BEAMS

The aim of this study is to clarify cell cycle distribution and cytotoxicity after carbon-ion beams (C-ions). One human malignant melanoma cell line, HMV-I was exposed to X-rays or 290 MeV/u C-ions at the center of SOBP. We applied flow cytometry technique and colony formation assay. C-ions induced G2/M arrest effectively more than X-rays at 24 h. The iso-effect dose, i.e. the 10% survival dose (5.0Gy for X-rays, 2.7Gy for C-ions) was used to examine the cell cycle kinetics. G2/M fraction increased immediately after irradiations, and showed a peak at 15 h. G2/M arrest cells were stayed long time after C-ions, whereas it released quickly after X-rays. In addition, the mRNA expression of molecules related with the arrest was suppressed with D10 dose and the effects were transitory after X-rays, whereas C-ions showed prolonged suppression. The arrest was released significantly by caffeine, and the cell killing by C-ions was enhanced with caffeine together. It is suggested that the release from G2/M arrest after C-ions can enhance the cytotoxic effects. Repair of complex DNA damage by C-ions takes long time. When it released intermediate of the process, incomplete repaired damage cause cell death.MICROS 2009 15th International Symposium on Microdosimetr