Sporicidal kinetics of Bacillus subtilis spores by heated scallop shell powder

Scallop shell powder heated at 1,000 degrees C for 1 h exhibited sporicidal action against Bacillus subtilis spores. The sporicidal kinetics of this action were analyzed with the use of a nonlogarithmic model. Apparent death rate constants (k) were obtained under various conditions. The value of k increased with powder concentration but became constant beyond the concentration representing the solubility of Ca(OH)2. A linear inverse relationship between k and temperature was found, and from this relationship the activation energy required for the death of B. subtilis spores in the heated shell powder slurry could be determined.     

Random sampling approach to state estimation in switching environments

This paper deals with the state estimation for the systems under measurement noise whose mean and covariance change with Markov transition probabilities. The minimum variance estimate for the state involves consideration of a prohibitively large number of sequences, so that the usual computation method becomes impractical. In the algorithm proposed here, the estimate is calculated with a relatively small number of sequences sampled at random from the set of a large number of sequences. The average risk of the algorithm is shown to converge to the optimal average risk as the number of sampled sequences increases. An ideal sampling probability yielding a very fast convergence is found. The probability is approximated in a minimum mean squared sense by a probability according to which sequences can be sampled sequentially and with great ease. This policy of determination of sampling probability makes it possible to design practical and efficient algorithms. Digital simulation results show a good performance of the proposed algorithm.     

Radiation effect on partial pressure of fission product iodine

The knowledge of the partial pressure of fission product iodine is important for evaluating the FCCI (fuel cladding chemical interaction) in FBR. Thermodynamical analysis shows that iodine is believed to react with cesium so strongly that the partial pressure of iodine is kept too low to cause FCCI. A molecule of cesium iodide is, however, excited by radiation in the reactor and dissociates into radical and ion. In this work, the radiation effect on the partial pressure of iodine is theoretically studied for the gaseous cesium-iodine system. Fission fragment flux is considered as the radiation and the iodine partial pressure is evaluated based on the theory of gaseous reaction. The results of the calculation show that the partial pressure of iodine can be increased enough to cause FCCI in the radiation field. In the case of the FBR fuel pin, the partial pressure of iodine under radiation conditions can be calculated to be ~ 10^?2 Pa (~10^?7 atm), which is higher than that of the non-radiation condition ~10^?9 Pa (~10^?14 atm). These calculations were carried out under the assumption that the cladding inner surface temperature was 873 K (600°C) and the oxygen potential was ?418 kJ/mol (?100 kcal/mol).     

Reliability evaluation of protective system with scheduled and unscheduled maintenance

Protective systems have two contradictory failures: one is failed-dangerous and the other is failed-safe. Scheduled maintenance is carried out to prevent these failures. Unscheduled maintenance is also carried out when the protective system shuts down the plant to be protected. This paper develops an integral equation for a statistically expected cumulative loss which is caused by the failures of the protective system and the plant. This equation represents special cases number of normal and spurious shutdowns, and hazards. An optimal scheduled maintenance interval is obtained, minimizing the expected loss.     

URE3] prion propagation is abolished by a mutation of the primary cytosolic Hsp70 of budding yeast

[URE3] and [PSI(+)] are infectious protein forms of the Saccharomyces cerevisiae Ure2p and Sup35p, respectively. We isolated an allele of SSA2, the primary cytosolic Hsp70, in a screen for mutants unable to maintain [URE3]. Designated ssa2-10, the mutation results in a leucine substitution for proline 395, a conserved residue of the peptide-binding domain. This allele also unexpectedly destabilizes [URE3] in newly formed heterozygotes: [URE3] is either absent in heterozygotes formed by crossing wild-type [URE3] cells with ssa2-10 mutants, or present and fully stable. SSA2 deletion mutants are weakly capable of maintaining [URE3]. The ssa2-10 allele is compatible with propagation of [PSI(+)]. However, in combination with a deletion of SSA1, ssa2-10 eliminates the nonsense-suppression phenotype of [PSI(+)] cells.     

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Lactoferrin Ameliorates Dry Eye Disease Potentially through Enhancement of Short-Chain Fatty Acid Production by Gut Microbiota in Mice

Lactoferrin is a glycoprotein found at high concentrations within exocrine secretions, including tears. Low levels of lactoferrin have been implicated in the loss of tear secretion and ageing. Furthermore, lactoferrin possesses a range of functionalities, including anti-inflammatory properties and the ability to modulate the gut microbiota. Expanding evidence demonstrates a crucial role of the gut microbiota in immune regulation and development. The specific composition of bacterial species of the gut has a profound influence on local and systemic inflammation, leading to a protective capacity against a number of inflammatory diseases, potentially by the induction of regulatory immune cells. In this study, we demonstrated that oral administration of lactoferrin maintains tear secretion in a restraint and desiccating stress induced mouse model of dry eye disease. Furthermore, we revealed that lactoferrin induces the reduction of inflammatory cytokines, modulates gut microbiota, and induces short-chain fatty acid production. Whereas, the antibiotic vancomycin abrogates the effects of lactoferrin on dry eye disease and significantly reduces short-chain fatty acid concentrations. Therefore, this protective effect of LF against a mice model of DED may be explained by our observations of an altered gut microbiota and an enhanced production of immunomodulatory short-chain fatty acids.     

A novel dry photopolymer for volume‐phase holograms

A novel photopolymer for the fabrication of high‐resolution volume‐phase holograms, which primarily are used for holographic optical elements, is reported. This photopolymer consists of a thermosetting resin as a polymeric binder, a polyfunctional monomer, a photoinitiator, and a sensitizing dye. The chemistry to form images is based on the polymerization of an acrylic monomer initiated by radical species while making the holographic exposure, and accelerated diffusion transfer of the polymerized monomer with postexposure baking, and of a bisphenol‐type epoxy resin as a binder initiated by cations with UV exposure, which are generated through photodecomposition of a diaryliodonium salt‐sensitized 3‐ketocoumarin dye. Exposure of these photopolymer films to an Ar⁺ laser beam emitting 514.5 nm light at 60–150 mJ/cm² and subsequent heat treatment resulted in a refractive index alteration according to the light intensity. With this dry process, high diffraction efficiency and heat‐stable holograms can be formed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2189–2200, 2000     

A Film Diffusional Effect on the Apparent Kinetic Parameters in Packed-Bed Immobilized Enzyme Reactors

A film diffusional effect on the apparent kinetic parameters in packed-bed reactors containing the enzyme immobilized on the surface of a nonporous support was investigated. A comparison of the plug-flow reactor model equation, expressed analytically in terms of the apparent kinetic parameters, with experimental data showed that the conventional linearized plot based on the reactor model equation was essentially nonlinear. Simulations for the apparent kinetic parameters were made using the intrinsic kinetic parameters and volumetric mass-transfer coefficient previously determined from experimental data. Consequently, the apparent kinetic parameters were found to decrease monotonically with the increase of liquid flow rate. On the other hand, with the increase of reactor-inlet substrate concentration, these constants first increased, passed through a maximum, and finally decreased toward their respective intrinsic values. © 1997 SCI.     

Heat and mass transfer in super active carbon/ethanol adsorption heat pump with a packed bed type adsorber

The possibility of producing cold heat energy by a super active carbon/ethanol adsorption heat pump (AHP) with a packed bed type adsorber is discussed on the basis of both experimental and calculated results of the transient behavior accompanied by this operation. The trend in experimental results for heat and mass transfer agrees well with computer simulation for closed-system, one-component, non-isothermal conditions in both the adsorption and desorption processes. The super active carbon/ethanol AHP proposed generates a high level of cold heat energy by raising the desorption temperature. Therefore, this AHP is applicable to a refrigerator. However, it is suggested that enhancement of heat transfer in the adsorber is indispensable to obtain a high power from this type of AHP. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(7): 466–475, 1996