Wavelength division two-way fibre-optic transmission experiments using micro-optic duplexers

Experimental two-way transmission of high-speed digital pulse signals over a single 10 km optical fibre line has been realised at 800 nm band, employing newly developed small size and low-loss micro-optic duplexers, AlGaAs d.h. lasers of different emission wavelengths, a spliced graded-index high-silica fibre and Si-a.p.d.s.     

Assembly and Photoinduced Organization of Mono‐ and Oligopeptide Molecules Containing an Azobenzene Moiety

Assembled systems consisting of an azobenzene moiety as the photofunctional component and valyl units as the network backbone are investigated. The molecular ordering of these assemblies is examined by spectroscopy and theoretical calculations. The number of valyl units greatly influences the molecular order in the organized systems. Only N‐(L ‐valyl‐L ‐valyl‐L ‐valyl)azobenzene‐4‐carboxamide ( 3 ) forms a complete β‐sheet structure in this artificial assembly. Upon photoirradiation, the azobenzene moieties isomerize completely, revealing the reversibility in the structural organization through the flexibility of the β‐sheet network in this system.     

Measurement of droplet size distribution in core region of high-speed spray by micro-probe L2F

In order to investigate the distribution of droplet sizes in the core region of diesel fuel spray, instantaneous measurement of droplet sizes was conducted by an advanced laser 2-focus velocimeter （L2F）. The micro-scale probe of the L2F is made up of two foci and the distance between them is 36 lain. The tested nozzle had a 0.2 mm diameter single-hole. The measurements of injection pressure, needle lift, and crank angle were synchronized with the measurement by the L2F at the position 10 mm downstream from the nozzle exit. It is clearly shown that the droplet near the spray axis is larger than that in the off-axis region under the needle full lift condition and that the spatial distribution of droplet sizes varies temporally. It is found that the probability density distribution of droplet sizes in the spray core region can be fitted m the Nukiyama-Tanasawa distribution in most injection periods.     

Molecular Features and Clinical Management of Hereditary Pancreatic Cancer Syndromes and Familial Pancreatic Cancer

Hereditary pancreatic cancers are caused by several inherited genes. Familial pancreatic cancer is defined as pancreatic cancer arising in a patient with at least two first-degree relatives with pancreatic cancer in the absence of an identified genetic cause. Hereditary pancreatic cancer syndromes and familial pancreatic cancers account for about 10% of pancreatic cancer cases. Germline mutations in BRCA1, BRCA2, ATM, PALB2, CDKN2A, STK11, and TP53 and mismatch repair genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) are among the well-known inherited susceptibility genes. Currently available targeted medications include poly (ADP-ribose) polymerase inhibitors (PARP) for cases with mutant BRCA and immune checkpoint inhibitors for cases with mismatch repair deficiency. Loss of heterozygosity of hereditary pancreatic cancer susceptibility genes such as BRCA1/2 plays a key role in carcinogenesis and sensitivity to PARP inhibitors. Signature 3 identified by whole genome sequencing is also associated with homologous recombination deficiency and sensitivity to targeted therapies. In this review, we summarize molecular features and treatments of hereditary pancreatic cancer syndromes and surveillance procedures for unaffected high-risk cases. We also review transgenic murine models to gain a better understanding of carcinogenesis in hereditary pancreatic cancer.     

Fractal dimension analysis for run length diagnosis of Monte Carlo criticality calculation

In Monte Carlo criticality calculation (MCCC), each output quantity of interest is a series of tallies under autocorrelation. As a consequence from the functional central limit theorem, the stepwise interpolation of standardized tallies (SIST) converges in distribution to Brownian bridge (BB). Here, the standardization of tallies is a functional version of the statistic in the central limit theorem with the sample mean at each generation and the true mean replaced by the sample mean at the final generation. Fractional Brownian motion (FBM) is a family of stochastic processes including Brownian motion and assumes a unique value of the box-counting dimension (BCD) in fractal geometry. This work shows that the BCD of SIST is an effective diagnostic measure for the run length of MCCC. The sufficiency of the number of generations run can be judged by relating the BCD of FBM to that of BB. Numerical results are presented for the tallies of representative autocorrelation characteristics in a three-dimensional model of a pressurized water reactor and the effective multiplication factor (k_eff) tallies of the criticality problem by D. Mennerdahl.     

Epimerization and Decomposition of Kojibiose and Sophorose by Heat Treatment under Neutral pH Conditions

We evaluated the stabilities of kojibiose and sophorose when heated under neutral pH conditions. Kojibiose and sophorose epimerized at the C-2 position of glucose on the reducing end, resulting in the production of 2-O-α-D-glucopyranosyl-D-mannose and 2-O-β-D-glucopyranosyl-D-mannose, respectively. Under weak alkaline conditions, kojibiose was decomposed due to heating into its mono-dehydrated derivatives, including 3-deoxy-2,3-unsaturated compounds and bicyclic 3,6-anhydro compounds. Following these experiments, we propose a kinetic model for the epimerization and decomposition of kojibiose and sophorose by heat treatment under neutral pH and alkaline conditions. The proposed model shows a good fit with the experimental data collected in this study. The rate constants of a reversible epimerization of kojibiose at pH 7.5 and 90 °C were (1.6 ± 0.1) × 10⁻⁵ s⁻¹ and (3.2 ± 0.2) × 10⁻⁵ s⁻¹ for the forward and reverse reactions, respectively, and were almost identical to those [(1.5 ± 0.1) × 10⁻⁵ s⁻¹ and (3.5 ± 0.4) × 10⁻⁵ s⁻¹] of sophorose. The rate constant of the decomposition reaction for kojibiose was (4.7 ± 1.1) × 10⁻⁷ s⁻¹ whereas that for sophorose [(3.7 ± 0.2) × 10⁻⁶ s⁻¹] was about ten times higher. The epimerization reaction was not significantly affected by the variation in the buffer except for a borate buffer, and depended instead upon the pH value (concentration of hydroxide ions), indicating that epimerization occurred as a function of the hydroxide ion. These instabilities are an extension of the neutral pH conditions for keto-enol tautomerization that are often observed under strong alkaline conditions.     

Effect of MgO addition to upgraded brown coal on ash-deposition behavior during combustion

The objectives of this study were the evaluation of the effect of MgO addition to coal on the reduction of ash deposition during upgraded brown coal (UBC) combustion, and the elucidation of the mechanisms of the reduction of ash deposition. The melting temperature of UBC ash is 1494 K, which is lower than that of bituminous coal ash. Before the actual ash-deposition experiments, the molten slag fraction in the UBC ash was estimated by means of chemical equilibrium calculations for various mixing mass ratios of MgO to coal ash. The simulation results indicate that MgO addition plays a role in decreasing the molten slag fraction. It was confirmed that Mg formed solid composites with Si, Fe, Al, Ca, and Mn, and played a role in decreasing the molten slag fraction in the ash on the tube. As a next step, ash-deposition tests were conducted using a pilot-scale pulverized coal combustion furnace equipped with a refractory wall. The results showed that MgO addition contributed to decreasing the rate of ash deposition even for UBC. These calculations and experimental results suggested that one of the reduction mechanisms due to MgO addition involved the production of solid-phase aluminosilicates.