Demonstration of an ion-implanted, wavelength-shifted quantum-well laser

A technique for fabricating many different wavelength lasers on the same wafer has been developed. High energy ion implantation was used to selectively blue shift the emission wavelength of an InP-based quantum well laser structure. This structure was then processed into fully functional broad-area lasers whose current threshold was unaffected by the implantation process, indicating extremely high material quality after bandgap-shifting. This process has the potential for the integration of not only different wavelength lasers, but also other devices, such as waveguides, detectors, modulators, etc., on a single wafer.     

Improvement of shelf-life and wholesomeness of ground beef by irradiation-2. Chemical analysis and sensory evaluation

Lean ground beef was exposed to three dose levels of gamma radiations (Cobalt-60) (1·0, 2·5 and 5·0 kGy). Chemical indices monitored throughout the storage period (16 days, 4°C) included pH, free fatty acids and peroxides. Irradiation clearly contributed to a diminution of the pH and an increase of the peroxides. Free fatty acids were not affected. The 10 non-expert panellists indicated a noticeable effect of irradiation on the odour and colour of the raw product. The odour and flavour of the irradiated cooked ground beef was slightly disliked while no difference was perceived in the colour and texture of the cooked irradiated ground beef. Following these considerations, it is recommended that ground beef be treated with a low dose (such as 1 kGy).     

Investigation of corrosion and container integrity in metal food containers using scanning electron microscopy-X-ray microanalysis

Scanning electron microscopy and x-ray microanalysis were used to investigate microleakage, two incidences of loss of coating integrity, filiform corrosion, and sulfide black corrosion in enamel-lined metal food containers. Microleakage developed in a canned cheese sauce at the side seam weld and was traced to a hot weld and a cold weld defect. An enamel-blistering problem developed in an aseptically processed milk-based product when the tinplate was heated above its melting point; the tin melted under the enamel coating, causing the blistering. An enamel-blistering problem, due to silicon contamination of the metal surface prior to enameling, developed on the bottom of a two-piece can that contained a chicken-based product. A sulfide black problem developed in canned clams, caused by scratches in the coating that were introduced during can manufacturing. A filiform corrosion problem developed on the outside of the easy score line of enameled tinplate lids with a light tin coating 0.08 microns thick.     

Eyepiece focus and vergence/accommodation conflict: Implications for night‐vision devices

Abstract— Aviation increasingly conducts night operations using night‐vision devices. However, design of some aspects may limit performance. As pointed out by Kotulak, vergence/accommodation mismatch in NVDs, usually due to eyepiece focus misadjustments, is sometimes a source of visual acuity (VA) decrement. The increased separation between sensors, existing in some binocular helmetmounted displays, was also identified to be potentially responsible for decreased VA at short distances. Based upon knowledge pertaining to vergence and accommodation, a study was performed to better understand the problem of dissociation accommodation/convergence. Different conditions of interocular separation and viewing distances were used. Twelve subjects participated and were asked to resolve Landolt C charts using night‐vision goggles. The results show that, with the eyepiece focus fixed at 10 m, the decrease in VA is roughly proportional to the interocular separation, when looking at short distances. A fixed eyepiece focus at 4 m considerably reduces the conflict and results in improved VA. An additional experiment was conducted to investigate the effect of fixing the objective lenses focus at infinity. With this setting, the decrease in VA at a short distance was such that effects of the mismatch accommodation/convergence are no longer apparent regardless of the interocular separation.     

Regulation of p53 levels by the E1B 55-kilodalton protein and E4orf6 in adenovirus-infected cells

The adenovirus type 5 243R E1A protein induces p53-dependent apoptosis in the absence of the 19- and 55-kDa E1B polypeptides. This effect appears to result from an accumulation of p53 protein and is unrelated to expression of E1B products. We now report that in the presence of the E1B 55-kDa polypeptide, the 289R E1A protein does not induce such p53 accumulation and, in fact, is able to block that induced by E1A 243R. This inhibition also requires the 289R-dependent transactivation of E4orf6 expression. E4orf6 is known to form complexes with the E1B 55-kDa protein and to function both in the transport and stabilization of viral mRNA and in shutoff of host cell protein synthesis. We demonstrated that the block in p53 accumulation is not due to the generalized shutoff of host cell metabolism. Rather, it appears to result from a mechanism targeted specifically to p53, most likely involving a decrease in the stability of p53 protein. The E1B 55-kDa protein is known to interact with both E4orf6 and p53, and as demonstrated recently by others, we showed that E4orf6 also binds directly to p53. Thus, multiple interactions between all three proteins may regulate p53 stability, resulting in the maintenance of low levels of p53 following virus infection.