Analyses of used BWR fuel assay data with the integrated burnup code system SWAT4.0

Criticality safety of the fuel debris from the Fukushima Daiichi Nuclear Power Plant is one of the most important issues, and the adoption of burnup credit is desired for criticality safety evaluation. To adopt the burnup credit, validation of the burnup calculation codes is required. Assay data of the used nuclear fuel irradiated by the Fukushima Daini Nuclear Power Plant Unit 2 are evaluated to validate the SWAT4.0 code for solving the BWR fuel burnup problem. The calculation results revealed that the number densities of many heavy nuclides and fission products show good agreement with the experimental data, except for those of ²³⁷Np, ²³⁸Pu, and samarium isotopes. These differences were considered to originate from inappropriate assumption of void fraction. Our results implied overestimation of the (n, γ) cross-section of ²³⁷Np in JENDL-4.0. The Calculation/Experiment – 1 (C/E–1) value did not depend on the type of fuel rod (UO₂ or UO₂–Gd₂O₃), which was similar to the case of PWR fuel. The differences in the number densities of ²³⁵U, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, ¹⁴⁹Sm, and ¹⁵¹Sm have a large impact on k_eff. However, the reactivity uncertainty related to the burnup analysis was less than 3%. These results indicate that SWAT4.0 appropriately analyzes the isotopic composition of BWR fuel, and it has sufficient accuracy to be adopted in the burnup credit evaluation of fuel debris.     

Epoxy Resin Particles, 3. Particle Formation of Epoxy Resin in Aqueous Emulsion State

A Bisphenol A‐type epoxy resin is readily emulsified in aqueous medium with an ethylene oxide adduct to a Friedel‐Crafts reaction product of styrene and 4‐(4‐cumyl)phenol as emulsifier. The resultant epoxy resin emulsion is reacted with amine‐type hardeners to obtain epoxy resin particles that are fully cross‐linked. The size and size distribution of the resultant particles are almost comparable to those of the primarily formed emulsion particles which are determined by the amount of emulsifier, mixing temperature and speed. The average diameter of the finally obtained particles ranges from 0.5 to 22 μm depending on the reaction conditions. The particles hardened with 1,2‐diaminoethane (DEA) have a spherical form with homogeneous surface, whereas the particles hardened with N,N ′‐bis(2‐aminoethyl)‐1,2‐diaminoethane (TTA) have a shrunk appearance with rough surface. These particles can readily be isolated from the dispersion without causing the solvent‐derived pollution for environment.     

Analysis of the constituents in jojoba wax used as a food additive by LC/MS/MS

Jojoba wax is a natural gum base used as a food additive in Japan, and is obtained from jojoba oil with a characteristically high melting point. Although the constituents of jojoba oil have been reported, the quality of jojoba wax used as a food additive has not yet been clarified. In order to evaluate its quality as a food additive and to obtain basic information useful for setting official standards, we investigated the constituents and their concentrations in jojoba wax. LC/MS analysis of the jojoba wax showed six peaks with [M+H]+ ions in the range from m/z 533.6 to 673.7 at intervals of m/z 28. After isolation of the components of the four main peaks by preparative LC/MS, the fatty acid and long chain alcohol moieties of the wax esters were analyzed by methanolysis and hydrolysis, followed by GC/MS. The results indicated that the main constituents in jojoba wax were various kinds of wax esters, namely eicosenyl octadecenoate (C20:1-C18:1) (1), eicosenyl eicosenoate (C20:1-C20:1) (II), docosenyl eicosenoate (C22:1-C20:1) (III), eicosenyl docosenoate (C20:1-C22:1) (IV) and tetracosenyl eiosenoate (C24:1-C20:1) (V). To confirm and quantify the wax esters in jojoba wax directly, LC/MS/MS analysis was performed. The product ions corresponding to the fatty acid moieties of the wax esters were observed, and by using the product ions derived from the protonated molecular ions of wax esters the fatty acid moieties were identified by MRM analysis. The concentrations of the wax esters I, II and III, in jojoba wax were 5.5, 21.4 and 37.8%, respectively. In summary, we clarified the main constituents of jojoba wax and quantified the molecular species of the wax esters without hydrolysis by monitoring their product ions, using a LC/MS/MS system.     

Transient gene expression in guard cell chloroplasts of tobacco using ArF excimer laser microablation

In this paper, we report a novel method for delivering genes into chloroplasts of tobacco cells using laser microablation. The plasmid pLD200-GFP was introduced into chloroplasts of Nicotiana tabacum cv. Xanthi guard cells and transient GFP expression was detected in the chloroplasts after 2-3 d of incubation. The technique uses an argon fluoride (ArF) excimer laser to perforate the cell surface in a 4 mum(2) area in the presence of plasmid coated gold microparticles. Pretreatment of guard cells to promote stomatal closure prior to laser ablation resulted in a significant increase in the survival rate of cells and a transient expression rate of 2-3% in trial number basis was archived. Our method has unique advantages such as avoiding laborious pretreatments that adversely affect cell viability and specific delivery of transgenes into a desired cell in complex leaf tissue. This technique is a potential tool for cell specific transient gene expression studies for elucidation of gene regulation and expression.     

PCR detection of Bacillus and Staphylococcus in various foods

A broad-range PCR assay for the detection of bacteria belonging to Bacillus and Staphylococcus genera was developed. Primers targeting the bacterial 16S rRNA gene were newly designed and used in a PCR assay. To determine the specificity of the assay, 81 different bacterial strains (of 50 genera), 2 fungi, 3 animals, and 4 plants were tested. Results were positive for every tested Bacillus, Staphylococcus, or Aerococcus strain. In addition, the result for Listeria grayi was positive with lower PCR product. For all other bacterial strains and eukaryotes tested, results were negative. Bacterial DNA was prepared with the use of achromopeptidase and Chelex 100 resin from culture after growth in brain heart infusion medium. To test the sensitivity of this PCR assay for Bacillus or Staphylococcus genus, either Bacillus cereus or Staphylococcus aureus was inoculated into various foods with undetectable levels of endogenous microbial contamination as an indicator. Inoculation of bacteria at 10 to 30 CFU/g of food was followed by a 5-h enrichment culture step after which the PCR assay allowed the detection of bacterial cells. When the inoculation (B. cereus or S. aureus) of 10 to 90 CFU/g into noodle foods containing endogenous microflora (10(3) to 10(5) CFU/g) was followed by a 6-h enrichment culture step, the PCR assay detected the bacteria. Including the enrichment culture step, the entire PCR detection process can be completed within 8.5 h.     

Gas holdup, liquid circulating velocity and mass transfer properties in a mini-scale external loop airlift bubble column

The external loop airlift bubble column has been regarded as a promising type of gas-liquid or gas-liquid-solid biooreactor because of the liquid circulating flow between the riser and downcomer. A mini-scale column is useful and efficient in the process research and development for highly specialized materials such as fine chemicals, advanced bioproducts and biocatalysts utilized in two or three phase system. In this work, a mini-scale glass column of in volume was designed and characterized. The gas holdup ε_G in the riser was obtained by measuring the volume expansion through photographs taken with a digital camera. The liquid circulating velocity U_L was measured by observing the time required for a tracer particle to travel a fixed distance in the downcomer through analysis of the images taken by a video camera. The gas-liquid volumetric oxygen transfer coefficient k_La and liquid-solid oxygen transfer coefficient k_S were determined by our previous method in which the air oxidation of glucose was catalysed by the immobilized glucose oxidase gel beads suspended in the column to obtain a pseudo steady state concentration of the dissolved oxygen and the corresponding constant rate of glucose consumption. It was shown that even such a mini-scale external loop bubble column could be characterized in terms of gas holdup, liquid circulating velocity and mass transfer properties according to our previous correlations proposed for the bench to pilot scale column.     

A New Hypothetical Concept in Metabolic Understanding of Cardiac Fibrosis: Glycolysis Combined with TGF-β and KLF5 Signaling

The accumulation of fibrosis in cardiac tissues is one of the leading causes of heart failure. The principal cellular effectors in cardiac fibrosis are activated fibroblasts and myofibroblasts, which serve as the primary source of matrix proteins. TGF-β signaling pathways play a prominent role in cardiac fibrosis. The control of TGF-β by KLF5 in cardiac fibrosis has been demonstrated for modulating cardiovascular remodeling. Since the expression of KLF5 is reduced, the accumulation of fibrosis diminishes. Because the molecular mechanism of fibrosis is still being explored, there are currently few options for effectively reducing or reversing it. Studying metabolic alterations is considered an essential process that supports the explanation of fibrosis in a variety of organs and especially the glycolysis alteration in the heart. However, the interplay among the main factors involved in fibrosis pathogenesis, namely TGF-β, KLF5, and the metabolic process in glycolysis, is still indistinct. In this review, we explain what we know about cardiac fibroblasts and how they could help with heart repair. Moreover, we hypothesize and summarize the knowledge trend on the molecular mechanism of TGF-β, KLF5, the role of the glycolysis pathway in fibrosis, and present the future therapy of cardiac fibrosis. These studies may target therapies that could become important strategies for fibrosis reduction in the future.     

The effect of builders on the activity of protease enzymes

The effect of builders on the stability of protease enzyme activity was studied in an effort to identify superior builders which are soluble in water and compatible with enzymes formulated into heavy duty laundry powders. Various poly(styrenesulfonate-methacrylate) copolymers, polyacrylate and tripolyphosphate anionic builders, as well as various poly(vinylalcohol-vinylacetate) nonionic copolymers, namely PVAs, were used. Zeolite 4A was also used as a typical nonphosphate particulate builder in the detergents. The protease used is frombacillus stearothermophilus. The calcium content was determined to be 16.7 mole/mole of protease by atomic spectrophotometry. In binary systems composed of a fixed concentration of 10 U/mL protease and varied concentrations of compound, builder or surfacant, it was found that compounds having the larger calcium ion binding capacity (C.B.C.) lowered the relative activity of protease enzyme. The activity of protease enzyme alone was lowered about 20% by addition of 0.02% sodium dodecylbenzene sulfonate (DBS). The anionic builders added to the binary system of fixed 10 U/mL protease and 0.02% DBS reduce the protease enzyme activity in proportion to the magnitude of their C.B.C. Addition of anionic builders further lowered the protease enzyme activity. The nonionic builders and the nonionic surfactant can enhance the protease enzyme activity by protection of protease against the inhibitor, DBS. It is certain that calcium atoms contained in the protease must play an important role for the protease enzyme activity and its stability. Calcium atoms must have a great influence on the formation of protease-substrate complex, protease-compound complex and substrate-compound complex, because the protease, protein substrate and anionic compound would all be negatively charged in alkaline solutions. Builders for enzyme-containing detergents should be constructed to be insensitive to calcium ion.     

Modification of Takaishi-Sensui formula for a diaphragm gauge system connected by an arbitrary length pipe

The thermal transpiration effect in a vacuum system, where a circular pipe connects a capacitance diaphragm gauge (CDG) and a vacuum vessel, was numerically investigated using the direct simulation Monte Carlo (DSMC) method. The simulated pressure ratios were plotted versus the Knudsen number K, over the range 10⁻³ ≤ K ≤ 10³, for a fixed diameter and various pipe lengths. The curve obtained here was compared with that obtained using the Takaishi-Sensui formula (T-S curve). For a long pipe, with λ ≥ 10, (λ: aspect ratio of length to diameter), the simulated curve agreed well with the T-S curve over the entire examined range of K. For a shorter pipe (λ < 10), the simulated curve seemed to shift in the low K (high pressure) direction, with respect to the T-S curve, and the distance between the curves abruptly increased with decreasing λ. The discrepancy for a short pipe was found to be removable by rescaling the Knudsen number. The discrepancy that originally existed for a long pipe could also be reduced, if the reflection on the pipe wall obeyed an incompletely accommodated Maxwell model.     

N-alkylated nitrogen-in-the-ring sugars: conformational basis of inhibition of glycosidases and HIV-1 replication

The conformations of nitrogen-in-the-ring sugars and their N-alkyl derivatives were studied from 1H NMR analyses, mainly using 3J(H,H) coupling constants and quantitative NOE experiments. No significant difference was seen in the ring conformation of 1-deoxynojirimycin (1), N-methyl-1-deoxynojirimycin (2), and N-butyl-1-deoxynojirimycin (3). However, it was shown that the C6 OH group in 1 is predominantly equatorial to the piperidine ring, while that in 2 or 3 is predominantly axial, and its N-alkyl group is oriented equatorially. In the furanose analogues 1,4-dideoxy-1,4-imino-D-arabinitol (4) and its N-methyl (5) and N-butyl (6) derivatives, the five-membered ring conformation differed significantly by the presence or absence of the N-substituted group and the length of the N-alkyl chain. Compound 3 reduced its inhibitory effect on almost all glycosidases, resulting in an extremely specific inhibitor for processing alpha-glucosidase I since N-alkylation of 1 is known to enhance both the potency and specificity of this enzyme in vitro and in vivo. This preferred (C6 OH axial) conformation in 2 and 3 appears to be responsible for their strong alpha-glucosidase I activity. Compound 4 is a good inhibitor of intestinal alpha-glucohydrolases, alpha-glucosidase II, and Golgi alpha-mannosidases I and II, but its N-alkyl derivatives 5 and 6 markedly decreased inhibitory potential for all enzymes tested. In the case of 2,5-dideoxy-2,5-imino-D-mannitol (DMDP, 7), which is a potent beta-galactosidase inhibitor, its N-methyl (8) and N-butyl (9) derivatives completely lost potency toward beta-galactosidase as well. N-Alkylation of compounds 4 and 7, known well as potent yeast alpha-glucosidase inhibitors, resulted in a serious loss of inhibitory activity toward yeast alpha-glucohydrolases. Activity of these nine analogues against HIV-1 replication was determined, based on the inhibition of virus-induced cytopathogenicity in MT-4 and MOLT-4 cells. Compounds 2 and 3, which are better inhibitors of alpha-glucosidase I than 1, proved active with EC50 values of 69 and 49 micrograms/mL in MT-4 cells and 100 and 37 micrograms/mL in MOLT-4 cells, respectively, while none of the furanose analogues exhibited any inhibitory effects on HIV-1. The change in potency and specificity of bioactivity by N-alkylation of nitrogen-in-the-ring sugars appears to be correlated with their conformational change.