Effect of sample preparation and bacterial concentration on Salmonella enterica detection in poultry meat using culture methods and PCR assaying of preenrichment broths

We evaluated the sensitivity of a PCR assay in the detection of Salmonella enterica at the broth preenrichment step of poultry meat. A total of 162 retail poultry meat samples, which were prepared by manual massaging, stomacher or no homogenization were compared for Salmonella recovery. Using these homogenization methods, the PCR assay at the broth preenrichment step detected Salmonella in, respectively, 48.9%, 62.2% and 50.0% of meat and giblet samples detected as Salmonella-positive using the culture method. In ground chicken, however, Salmonella was detected in 21.7% of samples treated by stomacher homogenization, compared to 40.7% and 48% of untreated and hand-massaged samples, respectively. These results suggest that stomaching of ground chicken causes excessive effusion of food constituents, which affects PCR results. Using the most probable number (MPN) technique, Salmonella was detected at under 1.0 CFU/g in 12 ground chicken samples and under 10³ CFU/ml of broth in seven of the 12 broth-enriched samples, which considered the minimum concentration detectable by PCR assay. These results show that Salmonella detection using routine PCR assays is difficult in poultry meat, and in particular ground chicken, due to low amounts of Salmonella and the presence of inhibitors.     

Effects of miscibility on probe tack of natural-rubber-based pressure-sensitive adhesives

Natural rubber (NR) was blended in various ratios with 29 kinds of tackifier resins, which were prepared from rosin, terpenes, and petroleum. Miscibilities of all the blend systems were illustrated as phase diagrams in our previous articles. From these blend systems, we selected 7 systems having typical phase diagrams [completely miscible, completely immiscible, and lower critical solution temperature (LCST) types] and carried out measurements of probe tack. Probe tack values were measured at various rates of separation and temperatures to obtain master curves. In the case of miscible pressure sensitive adhesives (PSAs) at the condition of measurement, the peak position in the master curve of probe tack shifted to the lower velocity (higher temperature) as the tackifier content increased. On the contrary, immiscible PSAs had much smaller probe tack values than miscible ones and did not give manifest shift of peaks. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 771–776, 1998     

Study of a failure mechanism during UIS switching of planar PT-IGBT with current sense cell

IGBT with sense emitter cells are used in power applications where current sensing or feedback is needed to guarantee safe operation of the switching device. In this paper we show, by experimental measurements and simulations, how the coupling of undesired voltages to the sense cell that is disconnected from the main IGBT emitter is able to trigger the latch-up of the entire device during inductive switching leading to its failure. Being able to reproduce the failure phenomenon by 2D simulations we are able to identify the possible physical cause of this phenomenon.     

Gene expression in the supraoptic nucleus.

The magnocellular neurosecretory cells (MNCs) in the supraoptic nucleus (SON) express multiple kinds of genes, including not only the classical hormones arginine vasopressin (AVP) and oxytocin (OXT), but also other physiologically active substances including neuropeptides, their receptors, and nitric oxide (NO) synthase, the rate-limiting enzyme in the synthesis of NO under physiological condition. For example, osmotic stimuli such as dehydration and chronic salt loading cause a wide range of changes of the expression levels of the genes and marked induction of the expression of the genes in the SON. The expression of the NO synthase gene in the SON under physiological conditions is reviewed.     

Development of elevated temperature structural design guide for Japanese demonstration breeder reactor

Programs to develop the “elevated temperature structural design guide for the demonstration fast breeder reactor” (DDS) in Japan have been conducted since 1987. The DDS is to be developed on the basis of the “elevated temperature structural design guide for class 1 components of prototype fast breeder reactors” (ETSDG), by considering structural and material features of the demonstration fast breeder reactor (DFBR) and incorporating results of the latest R&D. This paper describes the progress of the R& D concept of the DDS, and discusses some typical results of current studies on the DDS.     

New materials which respond to visible light: functional polymers containing zirconium

Photoresponsive polymers which change their magnetic properties when illuminated by visible light have been found. n-Butyl zirconate was polymerized in tetrahydrofuran and other solvents. The polymer, when illuminated, changes its conformation and a new spin-nuclear interaction in the electron spin resonance spectrum is observed. These polymers, when 1 wt% Pt was added, exhibited photocatalytic activities and photolysed a 1:1 methanol-H₂O mixture and a 0.24 M Na₂S aqueous solution, using visible light of wavelength 480 to 730 nm.     

Effect of self-representation of interaction history by the robot on perceptions of mind and positive relationship: a case study on a home-use robot

A question in research is concerning the most important factors for increasing the motivation of a human to continue interacting with an interactional robot. Previous studies have argued that the perceptions of mind and interactability of the robot by the interacting human are essential factors. However, ways of improving such perceptions have not sufficiently investigated. In this study, we focused on the case of a home-use interactional robot and investigated ways to improve such perceptions. We proposed the perceived interaction history of the robot to be another essential factor and hypothesized that adding this factor can promote the perceptions of mind and positive relationship. We conducted a human–robot interaction experiment with 32 human subjects, and the experimental results verified our hypothesis.     

Characterization of mono- and multilayered films with Mn-doped ZnS nanoparticles and luminescence properties of the monolayered films prepared by applying magnetic fields

Mn²⁺-doped ZnS (ZnS:Mn) nanoparticles were prepared using bis(2-ethylhexyl) sulfosuccinate (AOT) reversed micelle method. Luminescence at 583-589 nm were observed in the ZnS:Mn nanoparticles and are ascribed to Mn²⁺ ion in the nanoparticles due to energy transfer from ZnS. The luminescence was enhanced by capping with alkanethiol. Mono-and multilayered films with the alkanethiol-capped ZnS:Mn nanoparticles were fabricated on quartz substrates by layer-by-layer method using self-assembled monolayer (SAM) of 1,6-hexanedithiol. The polarization degrees of luminescence for the monolayered films were enhanced by preparation under applying magnetic field. The enhancements are probably caused by magnetic orientation of the ZnS:Mn nanoparticles on the quartz substrates.