Local plastic deformation in the vicinity of grain boundaries in Fe–3 mass% Si alloy bicrystals and tricrystal

Nanoindentation was used to study incipient plastic deformation in the vicinity of grain boundaries of different character in Fe–3 mass% Si alloy bicrystals and tricrystal. Pop-in events associated with the grain boundaries were observed in the load–displacement curves. From the pop-in hardness values, the critical stresses required to propagate the yield past the grain boundary were estimated to be in the range of approximately µ/400–µ/130 (where µ is the shear modulus) depending on the grain boundary character: the special boundaries usually had higher critical stresses than the general boundaries. A Hall–Petch (H–P) type relationship was found between the hardness and the distance of the indenter to the grain boundary. The H–P slopes obtained were approximately one order of magnitude lower than the macroscopic value of the H–P slope for the Fe–3 mass% Si alloy, and were generally lower for general grain boundaries than for special boundaries.     

Physicochemical state of the nanotopographic surface of commercially pure titanium following anodization-hydrothermal treatment reveals significantly improved hydrophilicity and surface energy profiles

A method of coating commercially pure titanium (cpTi) implants with a highly crystalline, thin hydroxyapatite (HA) layer using discharge anodic oxidation followed by hydrothermal treatment (Spark discharged Anodic oxidation treatment ; SA-treated cpTi) has been reported for use in clinical dentistry. We hypothesized that a thin HA layer with high crystallinity and nanostructured anodic titanium oxide film on such SA-treated cpTi implant surfaces might be a crucial function of their surface-specific potential energy. To test this, we analyzed anodic oxide (AO) cpTi and SA-treated cpTi disks by SEM and AFM. Contact angles and surface free energy of each disk surface was measured using FAMAS software. High-magnification SEM and AFM revealed the nanotopographic structure of the anodic titanium oxide film on SA-treated cpTi; however, this was not observed on the AO cpTi surface. The contact angle and surface free energy measurements were also significantly different between AO cpTi and SA-treated cpTi surfaces (Tukey's, P < 0.05). These data indicated that the change of physicochemical properties of an anodic titanium oxide film with HA crystals on an SA-treated cpTi surface may play a key role in the phenomenon of osteoconduction during the process of osseointegration.     

Innervated liver plays an inhibitory role in regulation of food intake

BACKGROUND: With the onset of eating, the associated rise of dopamine in the lateral hypothalamus (LHA-DA) is thought to regulate quantity of food consumed per meal. Early release of LHA-DA induced by eating is facilitated by oronasal stimulation; we propose that the subsequent LHA-DA response induced by nutrients in the portal vein is dampened by the innervated liver. This was tested by measuring LHA-DA in normal rats: during parenteral feeding to bypass oronasal stimulation, while eating during parenteral feeding, and while eating only. METHODS: Rats had either total liver denervation or sham operation, with placement of a jugular vein catheter and LHA-DA microdialysis cannula. After a 3-week recovery period total liver denervated rats were randomized to parenterally fed, food only, and parenteral plus food groups each with sham-operated controls in which LHA-DA was measured. RESULTS: No difference in LHA-DA release in food only groups occurred between total liver denervated or sham-operated rats. A significantly higher rise in LHA-DA was observed in total liver denervated versus sham-operated rats in parenterally fed (129% +/- 4% versus 116% +/- 2%; p < 0.05) and parenteral plus food (151% +/- 4% versus 134% +/- 4%; p < 0.05) groups. CONCLUSIONS: In total liver denervation versus sham operation, an increase in LHA-DA release occurs during parenteral feeding and eating during parenteral feeding, suggesting that innervated liver inhibits LHA-DA release.     

Defensive secretion of chrysomelid larvaeLinaeidea aenea linné andPlagiodera versicolora distincta Baly

The larval defensive secretions ofLinaeidea aenea Linné andPlagiodera versicolora distincta Baly were identified as plagiolactone and epiplagiolactone. In addition to these compounds, chrysomelidial and the acetates of hexadecanol, octadecanol and (Z)-I 1-eicosenol from the former insect, and plagiodial and epichrysomelidial from latter insect were identified.This is report No. 3 of the Defensive Secretion of Chrysomelid Beetles. Report No. 2 is Sugawara et al., 1979.     

Effect of physical activity on the distensibility of the aortic wall in healthy males

BACKGROUND AND PURPOSE: Diethylenetriamine penta acetic acid (99mTc-DTPA), a substance which indicates glomerular filtration, is distributed equally in blood and tissue after a bolus intravenously injection. Ambulatory Renal Monitor (ARM) is a portable and non invasive device which monitors extracorporeally the clearance of intravenously injected 99mTc-DTPA. We examined correlation between half-time of clearance estimated by ARM and glomerular filtration rare, and clinical usefulness of ARM for a renal function monitoring. MATERIALS AND METHODS: The purposes of this paper are to describe the results obtained through basic analysis experiments and reproducibility in normal control, and its clinical application for 9 renal transplant patients, three drug-induced renal damage, one acute renal failure, one hemolytic uremic syndrome (HUS), two chronic nephritis, one donor of renal transplantation, one ureteral tumor, three renal tumors, two ureteral stones, one bilateral hydronephrosis and two normal controls. The half time of clearance of the tracer measured by an ARM. (ARM-HTC) is compared with the half time of clearance of the tracer measured by repeated blood sampling (Sampling-HTC) as a golden standard, serum creatinine and creatinine clearance. RESULTS: A significant correlation (linear) was detected when ARM-HTC was compared with Sampling-HTC (r = 0.91), 1/serum creatinine (r = 0.85) or creatinine clearance (r = 0.82), although ARM-HTC showed a delay compared with Sampling-HTC. CONCLUSIONS: The reason of this delay may be due to a difference in half-time when the tracer distributed in the blood and tissue. The results indicate that the estimation of 99mTc-DTPA clearance by ARM is valuable for renal function evaluation in wide ranges of renal function and in different origins of renal dysfunction such as in renal transplantation.     

Growth of Listeria monocytogenes on iceberg lettuce and solid media

The growth of pathogenic bacterium Listeria monocytogenes on fresh-cut iceberg lettuce under constant temperatures was modelled in order to investigate microbial safety during distribution of this vegetable. We examined the effects of several incubation temperatures, ranging from 5 to 25 degrees C, on bacterial growth. These data were fitted to the Baranyi model and the curves showed a high correlation coefficient at all temperature (R2 > 0.95). In addition, the native bacterial flora of the lettuce did not affect the growth rate of L. monocytogenes regardless of incubation temperature. However, the lag time was reduced at a ratio of native bacteria to inoculated L. monocytogenes (100:1) at low incubation temperatures (5 and 10 degrees C). Furthermore, the maximum population density (MPD) was increased at a low ratio of native to inoculated L. monocytogenes (1:1) at all incubation temperatures. These results were compared with the previous work published by [Buchanan, R.L., Stahl, H.G., Whiting, R.C., 1989. Effects and interactions of temperature, pH, atmosphere, sodium chloride, and sodium nitrite on the growth of Listeria monocytogenes. J. Food Prot. 52, 844-851] that is being developed at the US Department of Agriculture (USDA) Agricultural Research Service's Pathogen Modelling Program (PMP). The broth-based Buchanan model for L. monocytogenes was found to markedly deviate from the observed data. In order to investigate this discrepancy, we examined the effects of medium environment and nutrient content on L. monocytogenes growth using tryptic soy agar plates (TSAP) and agar plates (AP) containing 1.7% sucrose. The inoculated bacteria on both TSAP and AP showed slower growth rates than that predicted by the PMP. The MPD of bacteria grown on TSAP was similar to the PMP model ( approximately 9 log10 CFU/ml or plate (circle of diameter of 90 mm)) regardless of the incubation temperature. By contrast, the MPD observed on AP was approximately 4 log10 CFU lower than that observed on TSAP or predicted by the PMP. Both the growth rate and the MPD of L. monocytogenes on AP were similar to those on lettuce. These results suggest that the solid medium and poor nutrient content inhibited the growth of L. monocytogenes on lettuce. The growth rates of the inoculated L. monocytogenes on all media were described using Ratkowsky's simple square root model.     

Behavior of Liquefied Sands Under Extremely Large Strain Levels in Cyclic Torsional Shear Tests

In order to study the cyclic behavior of liquefied sands at extremely large strain levels up to double amplitude shear strain of about 100%, a series of undrained cyclic torsional shear tests while keeping the specimen height constant was performed on saturated Toyoura sand under different densities, two kinds of in-situ frozen sandy samples and their reconstituted specimens. Due correction was made for the effect of membrane force on the measured shear stress. After exceeding a certain level of overall shear strain, the specimen deformation became non-uniform, which is called as “strain localization” in the present study. The initiation of such localization was associated with the changes in the cyclic amplitude of deviator stress and the increment of shear strain. In the case of Toyoura sand, the limiting value of shear strain to initiate strain localization was found to increase with decrease in the relative density, and such a trend was consistent with the empirical correlation of soil liquefaction when the relative density is higher than 30%. In the case of in-situ frozen sandy samples, their limiting shear strain values were smaller than those of the reconstituted specimens, suggesting that their soil structures were different from each other under different degrees of natural aging effects.     

A study on technical feasibility of applying tubular linear induction motor to vertical movement

It is necessary for a linear induction motor (LIM) to have large thrust force in applications for the vertical movement. If it does not have sufficient thrust force, it cannot lift even itself. A ratio (thrust force/weight of motor), therefore, is the most important factor for the design of this motor. In this paper, assuming the LIM has no slot-effect and infinite length, a simple analytical model is introduced for steady-state operation. By comparison with the results of detailed numerical analysis, it is verified to be applicable for basic evaluation of the motor. The design of the motor for vertical movement is carried out and the ratio is maximized. The basic dimensions of a feasible motor are given for such application.     

Modeling the Stress-Strain Relations of Sand in Cyclic Plane Strain Loading

A modeling procedure to simulate stress-strain relations of sand subjected to cyclic loading is proposed. Results from drained plane strain compression, extension, and cyclic loading tests on Toyoura sand are analyzed. The monotonic loading behavior is simulated by the generalized hyperbolic equation to use as the skeleton curves in the simulation of cyclic behavior. To construct hysteretic stress-strain curves based on the skeleton curves, the Masing’s rule is generalized to the proportional rule consisting of the internal and external rules. The drag rule is then introduced to simulate cyclic stress-strain behavior in which the stress amplitude increases at a decreasing rate during cyclic loading with a constant strain amplitude. It is assumed that any plastic shear strain increment taking place in a certain direction drags the whole skeleton curve for loading in the opposite direction towards the direction of the concerned shear strain increment. The measured cyclic stress-strain behavior is well simulated by the proposed method.     

An airborne smoke sampling package for field measurements of fires

A unique airborne smoke sample package (ASSP) for determining the smoke yield of large fires has been developed. The uncertainty in the average smoke yield at the 95% confidence interval is about ±7% of the average of three repeat measurements. The ASSP, which weighs less than 4 kg, is light enough to be flown suspended below a tethered helium-filled balloon or attached to a small radio-controlled aircraft. Measurements are made by flying the sampling equipment into a fire's smoke plume. Additional smoke plume measurements that can be made with the ASSP include particle size distribution using a cascade impactor, smoke agglomerate structure using transmission electron microscope (TEM) grids, and polycyclic aromatic hydrocarbons (PAHs) analysis using various sorbent tubes. The application of the ASSP in measuring laboratory and large outdoors petroleum pool fires is discussed. Smoke yield values measured in field burns of Louisiana crude oil range from 0.080 to 0.137, and the primary sphere diameter of the agglomerates is as large as 0.15 µm.