Collective memories of Germans and Japanese about the past half-century

We investigate the collective memories of two samples drawn in 1991, one from the former West Germany and one from Yokohama, Japan. In the early 1990s such samples included many members of World War II cohorts and also cohorts born long after that war had ended. We consider the relation of age, conceptualised as birth cohort, to the salience of memories of national and world events that were mentioned as important in response to a quite general open-ended question about the past half-century. The relations are similar across the two countries in so far as external events like World War II might have had similar impacts on each population, while each country is distinctive with regard to events that especially impinged upon it. Hypotheses about the importance of adolescence and early adulthood to the imprinting of memories are generally confirmed, but several types of evidence suggest the need to extend the delimiting ages to earlier than the mid-teens and later than the mid-twenties. Other evidence indicates the desirability of distinguishing between recent events that are the focus of media attention and earlier events that depend more fully on autobiographical memory.     

Risk factors for colorectal cancer in a prospective study among U.S. white men

The mRNA expression of presenilin-1 (PS1) and beta-amyloid precursor protein (betaAPP) was investigated in the embryonic day 20 rat olfactory bulb, nasal cavity, and inner ear using in situ hybridization histochemistry. In the olfactory bulb, PS1 mRNA was strongly expressed in both olfactory bulb neuroepithelium and the differentiating olfactory bulb. In contrast, betaAPP mRNA was preferentially expressed in differentiating fields. In the nasal cavity, PS1 mRNA was strongly expressed throughout the olfactory epithelium, while betaAPP mRNA expression was concentrated in the middle part of the epithelium. In the membrane labyrinth of the inner ear, although PS1 mRNA was evenly distributed in both sensory epithelium and supporting cells, betaAPP mRNA was exclusively expressed in the sensory epithelium. These data suggest that PS1 is expressed earlier than betaAPP, and that PS1 and betaAPP co-operatively play pivotal roles in the development of the olfactory and vestibulocochlear systems.     

A role for the cadherin family of cell adhesion molecules in hippocampal long-term potentiation

The cadherins are a family of cell-cell adhesion molecules that mediate Ca2+-dependent homophilic interactions between cells and transduce signals by interacting with cytoplasmic proteins. In the hippocampus, immunostaining combined with confocal microscopy revealed that both neural- (N-) and epithelial- (E-) cadherin are present at synaptic sites, implying a role in synaptic function. Pretreatment of hippocampal slices with antibodies (Abs) raised against the extracellular domain of either N-cad or E-cad had no effect on basal synaptic properties but significantly reduced long-term potentiation (LTP). Infusion of antagonistic peptides containing the His-Ala-Val (HAV) consensus sequence for cadherin dimerization also attenuated LTP induction without affecting previously established LTP. Because the intense synaptic stimulation associated with LTP induction might transiently deplete extracellular Ca2+ and hence potentially destabilize cadherin-cadherin interactions, we examined whether slices could be protected from inhibition by N-cad Abs or HAV peptides by raising the extracellular Ca2+ concentration. Indeed, we found that high extracellular Ca2+ prevented the block of LTP by these agents. Taken together, these results indicate that cadherins are involved in synaptic plasticity, and the stability of cadherin-cadherin bonds may be regulated by synaptic stimulation.     

Consistent lack of association between breast cancer and oral contraceptives using either hospital or neighborhood controls

BACKGROUND: Case-control studies of oral contraceptive use and breast cancer have used neighborhood, population, or hospital controls. METHODS: To determine whether this association differs according to type of controls, interview data from 131 incident cases of breast cancer were compared with those of 189 hospital controls and 182 neighborhood controls Study subjects were white females recruited between 1973 and 1975 from among residents of Baltimore City and County ages 18 to 59 years. RESULTS: Adjusted relative odds of breast cancer related to ever versus never use of oral contraceptives were 1.0 and 0.8, using hospital and neighborhood controls, respectively. Relative odds did not increase proportionally to duration of oral contraceptive use or to progestogen potency. Although few subjects had used oral contraceptives for more than 2 years, almost all pill brands contained more than 49 micrograms of ethinyl estradiol or of mestranol. CONCLUSIONS: Results from the present study do not support the hypothesis that early preparations of oral contraceptives increased breast cancer risk among white women, regardless of whether controls are neighbors of the cases or hospital patients. However, its conclusions cannot be generalized to women who began taking the pill before their first full-term birth or took it for more than 2 years.     

Poke-through protection

The author discusses a simple, yet effective approach to slowing the spread of fire through openings in buildings.     

Creating layers of concentrated inorganic particles by interdiffusion of polyethylenes in microlayers

Interdiffusion of a polymer pair in microlayers was exploited to increase the concentration of inorganic particles in one of the components. When microlayers of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) were taken into the melt, greater mobility of linear LLDPE chains compared to branched LDPE chains caused the layer boundary to move in the direction of the more slowly diffusing chains in a manner similar to the Kirkendall effect in metals. This resulted in substantial shrinkage of the LLDPE layers and corresponding thickening of the LDPE layers. Adding a particulate in the LLDPE did not impede the process of interdiffusion in the melt, and the resultant shrinkage served to increase the particle concentration. For example, resistivity of initially nonconductive LLDPE layers containing nickel platelets decreased by 6 orders of magnitude into the semiconductor range after shrinkage concentrated the particles. The concentrating effect was also demonstrated with TiO₂ particles and talc platelets. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2877–2885, 1999     

Study of Deformation Mechanisms in Titanium by Interrupted Rolling and Channel Die Compression Tests

The mechanisms of small plastic deformation of titanium (T40) during cold rolling and channel die compression by means of "interrupted in situ" EBSD orientation measurements were studied. These interrupted EBSD orientation measurements allow to determine the rotation flow field which leads to the development of the crystallographic texture during the plastic deformation. Results show that during rolling, tension twins and compression twins occur and various glide systems are activated, the number of grains being larger with twins than with slip traces. In channel die compression, only tension twins are observed in some grains, whereas slip traces can be spotted in almost all observed grains. The different stress conditions and different strain rates existing under the two modes of deformation lead to the activation of different deformation mechanisms.     

A Study of Twin Variant Selection and Twin Growth in Titanium

An in depth analysis on twin variant selection and twin growth character during compression by means of “interrupted in situ” EBSD orientation measurement was carried out. An experimental verification and geometrical analysis of the use of Schmid's law as a criterion for selecting twin variants was performed, and proved to be conclusive. Twin variants having Schmid factors higher than 0.4 have a good chance to be activated. The twin growth exhibits two modes: {11–22} twins show a tendency to multiple variants system (MVS) and {10–12} twins show predominant variant system (PVS). The Schmid factor plays an important role in MVS and PVS.     

Effects of fluorinated substituents on the refractive index and optical radiation resistance of methacrylates

Novel fluorinated methacrylate polymers were synthesized. The purpose was to produce polymers with low refractive indices and increased resistance to optical radiation damage. Six different fluorinated substituents were appended on the monomer before polymerization. Optical-quality samples were prepared, and their transmission spectra, through 0.8 cm thick samples, were obtained. Each sample was tested for refractive index and glass transition temperature. The samples absorbed 10 MRad gamma radiation from a ⁶⁰Co source in an air environment; their transmission spectra were recorded immediately after irradiation and again after seven days had elapsed. As expected, increasing the fluorine content in the side chains resulted in decreased refractive indices. Fluorine content also influenced optical radiation stability. One polymer, poly(1H,1H-heptafluorobutyl methacrylate) retained superior UV/visible transmission after irradiation. © 1993 John Wiley & Sons, Inc.     

Average sidelobe levels in corporate-feed arrays

The article looks at the practical aspect of tolerances on antenna design. We all know that our designs need to work after the variations caused by manufacturing. Tight tolerances are costly. The author takes us inside the feed network of an array, and shows the effects of errors, at different levels of the network, on the sidelobe performance. We can then specify the different parts properly, and produce antennas at the lowest cost