Confocal microscopy and microbial viability detection for food research.

Confocal microscopy offers several advantages over other conventional microscopic techniques as a tool for studying the interaction of bacteria with food and the role of food microstructure in product quality and safety. When using confocal microscopy, samples can be observed without extensive preparation processes, which allows for the evaluation of food without introducing artifacts. In addition, observations can be made in three dimensions without physically sectioning the specimen. The confocal microscope can be used to follow changes over a period of time, such as the development of the food structure or changes in microbial population during a process. Microbial attachment to and detachment from food and food contact surfaces with complex three-dimensional (3-D) structures can be observed in situ. The fate of microbial populations in food system depends on processing, distribution, and storage conditions as well as decontamination procedures that are applied to inactivate and remove them. The ability to determine the physiological status of microorganisms without disrupting their physical relationship with a food system can be useful for determining the means by which microorganisms survive decontamination treatments. Conventional culturing techniques can detect viable cells; however, these techniques lack the ability to locate viable cells in respect to the microscopic structures of food. Various microscopic methods take advantage of physiological changes in bacterial cells that are associated with the viability to assess the physiologic status of individual cells while retaining the ability to locate the cell within a food tissue system. This paper reviews the application of confocal microscopy in food research and direct observation of viable bacteria with emphasis on their use in food microbiology.     

Deposition of DLC film from adamantane by using pulsed discharge plasma CVD

Diamond like carbon films are deposited on silicon and quartz substrates using adamantane as a sole source of carbon by pulsed discharge plasma chemical vapor deposition. Tauc band gap of such films has been successfully tuned from 1.7eV to 2.9eV. Iodine incorporation is observed to favor the growth of such films and induces disorder in the films. It also brings down in energy the on-set of photon absorption. Such iodine incorporated diamond like carbon films may be interesting candidates for the new coming applications such as for heterojunction photovoltaic devices.     

Wide-area current differential backup protection employingbroadband communications and time transfer systems

As power systems grow larger, it is becoming difficult to achieve reach and time coordination in backup protection when using distance relays. To cope with those problems, current differential backup protection for a busbar and transmission circuits connected to that busbar on an inter-station or wide-area basis is proposed. The proposed system can operate better than conventional systems with respect to operation time, section selectivity, etc. A system configuration is also proposed to utilize ATM transmission networks and time synchronous systems which make the construction and operation of the proposed wide-area protection system easy and flexible     

Dimensional measurement of high aspect ratio micro structures with a resonating micro cantilever probe

 In non-destructive dimensional measurement of high aspect ratio micro structures (HARMS), optical methods cannot offer full three dimensional information due to the lack of observation light. Again, conventional mechanical measurement, such as a surface profiler or a coordinate measurement machine, cannot be applied because their stylus is too large. Furthermore, the AFM, though popular among the semiconductor industry, is also limited in terms of dimensional measurement, because its system is usually designed for planar samples. Thus, we have developed a new sensor-integrated micro resonating cantilever probe and a new dimensional measurement machine, which allows the probe's vertical access to microstructures in a sample. The new probe is made of tungsten carbide super hard alloy and possesses design flexibility according to its intended application. Validity of the system is confirmed through the measurement experiment of EDM drilled and chemically etched micro holes.     

Thermal stability and mechanical properties of Gd-Co-A1 bulk glass alloys

The glass forming ability of Gd-Co-A1 ternary alloy systems with a composition ranging from 50% to 70% （molar fraction） for Gd and from 5% to 40% （molar fraction） for AI were investigated by copper mold casting and Gd60Co25Al15 bulk glass alloy cylinders with the maximum diameter of 5 mm were obtained. The reduced glass transformation temperature （TG/Tm） and the distance of supercooling region ATx are 0.616 and 45 K, respectively for this Gd-Co-A1 alloy. The compressive fracture strength （σf） and elastic modulus （E） of Gd-Co-A1 glassy alloys are 1 170-1 380 MPa and 59-70 GPa, respectively. The Gd-AI-Co bulk glassy alloys with high glass forming ability and good mechanical properties are promising for the future development as a new type function materials.     

Chitosan-conjugated thermo-responsive polymer for the rapid removal of phenol in water

Chitosan-conjugated thermo-responsive polymers (PNIPAAm-CSs) containing 2.0–8.7% (w/w) chitosan were readily synthesized by the condensation of chitosan and poly(N-isopropylacrylamide-co-acrylic acid) with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. PNIPAAm-CSs were water-soluble at 30 °C, while they deposited above the lower critical solution temperature (LCST, ca. 34 °C in 50 mM sodium phosphate, pH 6.8). Tyrosinase-induced phenol oxidation was performed in the dilute aqueous polymer solution at 30 °C for the rapid binding of oxidized compounds to the amino moiety of PNIPAAm-CS. By heating and shaking the solution, the polymer containing highly concentrated oxidized compounds deposited and agglutinated to a condensed coagulate. Increasing polymer concentration and chitosan content in the polymer increased the removal of phenol and its oxidized compounds. When 1.0 g of PNIPAAm-CS containing 8.7% chitosan was employed for treating 1 l of contaminated water, the concentration of phenol (19 mg l⁻¹) was reduced below the detection limit (0.08 mg l⁻¹) within 2 h.     

Long-term follow-up of surgical patients with single-ventricle physiology: prognostic anatomical determinants

The objectives of this study were to compare the reliability and validity of written test formats that are widely used in medical education (multiple choice, uncued, extended matching, and true/false) and evaluate the effects of uncued examinations on long-term retention of medical knowledge. Uncued tests were introduced into a traditional course in general and systemic pathology (six interim tests). In the following year, students were given eight tests written in the four formats, each being used twice. The academic achievement of students in these 2 years was compared with that of students in 2 previous years, in which multiple choice tests were used. Measures of academic achievement included performance on a final comprehensive examination and the United States Medical Licensing Examination (USMLE). Student performance on uncued tests was consistent over time (i.e., there was no learning curve). Mean scores ranged from 77% to 84%, and coefficient alpha reliability estimates on 100-item tests were excellent (0.79 to 0.90). Extended matching tests were also reliable, with a mean coefficient alpha of 0.90. There was no significant relationship between test format and student performance on subsequent comprehensive examinations. Our results indicate that extended matching and uncued tests have considerable advantages over multiple choice and true/false examinations. They are more reliable, better able to discriminate the well-prepared from the marginal student, and well suited for tested core knowledge. Contrary to our expectation, extended matching questions with 20 choices presented to the student were as statistically reliable and valid as uncued queries with several hundred choices.     

Transient analyses for accelerator driven system PDS-XADS using the extended SIMMER-III code

Transient analyses for Preliminary Design Studies of an Experimental Accelerator Driven System (PDS-XADS) were performed with the reactor safety analysis code SIMMER-III, which was originally developed for the safety assessment of sodium-cooled fast reactors and recently extended by the authors so as to describe the XADS specifics such as subcritical core, strong external neutron source and lead–bismuth–eutectic (LBE) coolant. As transient scenarios, the following cases were analyzed in accordance with the PDS-XADS program: spurious beam trip (BT), unprotected beam overpower (UBOP), unprotected transient overpower (UTOP), unprotected loss of flow (ULOF) and unprotected blockage (UBL) in a single fuel assembly. In addition, to cover some core-melt situations and investigate the potential for recriticalities, so-called snap-shot analyses with ad hoc postulated severe blockage conditions were also investigated.The simulation results for BT and UBOP showed that immediate fuel damage might not take place under short-time beam interruption or a 100% increase of the external neutron source. Concerning UTOP, it was found that a reactivity jump of 1 $ would not lead to damage of the fuel and the cladding. The ULOF simulation showed that the remaining natural convection of the coolant would prevent the cladding from disruptions. In the simulation of UBL in a single fuel assembly, it was shown that no cladding failure might be expected, due to the radial heat transfer and the coolant flow in the hexcan gap. Under an artificial suppression of the radial heat transfer for this UBL case, a pin failure occurred in the simulation but subsequent fuel sweep-out into the upper plenum region would bring a reactivity reduction and no power excursion. The severe accident simulations starting from postulated blockage above an already disrupted core showed that a severe recriticality could be avoided by the fuel sweep-out into the dummy-assembly or hexcan gap regions.The present simulation results showed that the current PDS-XADS design has a remarkable resistance against severe transient scenarios even in core-degradation conditions.     

Investigation of liquid film behavior at the onset of flooding during adiabatic counter-current air–water two-phase flow in an inclined pipe

The liquid film characteristics at the onset of flooding in an inclined pipe (16 mm i.d. and 2.2 m in length) have been investigated experimentally. A constant electric current method and visual observation were utilized to elucidate the flow mechanisms at the onset of flooding. Two mechanisms are clarified to control the flooding in lower flooding and upper flooding, respectively. The lower flooding occurred at lower liquid flow rate and high pipe inclination angle. In this mechanism, the liquid film does not block the pipe cross-section. On the other hand, the upper flooding occurred at higher liquid flow rate and low pipe inclination angle. In this case, blocking of the pipe cross-section by large wave and entrainment plays an important role. The experimental data indicated that there was no reversal motion of liquid film at the onset of flooding during the operation of both lower flooding and upper flooding. The effects of pipe inclination angle on the onset of flooding are also discussed.