Accumulation of acetylcholine receptors is a necessary condition for normal accumulation of acetylcholinesterase during in vitro neuromuscular synaptogenesis

To study a step of the very complex processes of the formation of the neuromuscular junction (NMJ), we have analysed the clustering of acetylcholine receptors (AChR) and acetylcholinesterase (AChE) in myotubes cultured in various conditions. On the surface of rat myotubes cultured in the presence of spinal cord cells from embryonic rat, numerous AChE clusters appeared. Such clusters are always co-localized with AChR clusters, but the reverse is not true: the number of AChR clusters largely exceeds that of AChE clusters. Very few AChE clusters formed when such co-cultures were treated with monoclonal antibodies (mAbs) against the main immunogenic region (MIR) of the AChR, which provoke internalization and degradation of the AChRs of the muscular membrane. The total levels of AChE and proportions of molecular forms were unaffected. We also used non-innervated myotubes in which addition of agrin, a protein normally synthesized by motoneurons, transported to nerve terminals and inserted into the synaptic basal lamina, induces the formation of small clusters of AChE. When added to rat myotubes devoid of membrane AChR, agrin-induced AChE clusters did not form. Finally, we analysed the capacity of the variant of the C2 mouse muscle cell line deficient in AChR (1R-) to form clusters of AChE in co-cultures with spinal cord cells from rat: no formation of AChE clusters could be observed. In all these different systems of cultures, the conditions which prevented clustering of AChR (anti-AChR antibodies, deficiency of the variant C2 cell line) also suppressed AChE clustering. We concluded that clustering of AChR is a prerequisite for clustering of AChE, so that NMJ formation implies the sequential accumulation of these two components.     

Religious activity and depression among community-dwelling elderly persons with cancer: the moderating effect of race

OBJECTIVES: Research has been oriented toward elucidating the links between religion and mental health. The purpose of this article is to further our knowledge in this area by examining the effect of religious activity on depressive symptomatology among community-dwelling elderly persons with cancer. We also test whether these effects differ between Blacks and Whites. METHODS: We use two waves of data collected from a community-dwelling sample of elderly persons living in North Carolina. Depressive symptomatology is measured using four subscales from the CES-D 20 scale: somatic-retarded activity, depressed affect, positive affect, and interpersonal relations. Measures of religious activity include service attendance, religious devotion, and watching or listening to religious programs. RESULTS: The findings indicate that among Blacks with cancer, religious activity is related to lower levels of depressive symptomatology; no such relationship is found for respondent with other illnesses or no illness. Further, the effects of religious activity are stronger among Blacks than Whites. DISCUSSION: The analyses lend support to the hypothesis that religious activity is a strong predictor of depression in elderly adults with cancer. This finding, however, is not as strong as we had anticipated.     

PARTICLE-SIZE DISTRIBUTION OF GLAZES*

The particle-size distributions of experimental and commercial stains and glazes and glaze materials were determined by using the Andreasen pipette method. The variation in particle size of two porcelain glazes, raw and fritted, was correlated with the glaze working properties and certain physical properties of the glaze film, such as fluidity, microtexture, scratch-hardness, and glaze stress. The relation of grinding efficiency to length of milling time and different ball size was studied for these two glazes and also for a stain, and the color imparted by the stain at different grain sizes was noted.     

USE OF NEPHELINE SYENITE IN FLOOR-TILE AND WALL-TILE BODIES*

The physical properties of wall-tile bodies and floor-tile bodies are described. The wall-tile bodies are fluxed respectively with nepheline syenite; feldspar; talc and feldspar; talc and syenite; talc, pyrophyllite, and syenite; and talc, pyrophyllite, and feldspar. Floor-tile bodies, developing at lower temperatures, may be formulated with nepheline syenite. The greater refractoriness of American clays used in these bodies, as compared to English clays, is compensated for by the increased fluxing action of nepheline syenite.     

The impact of a media campaign in the reduction of risk-taking behavior on the part of drivers

As part of an ongoing media educational campaign to enhance pedestrian safety in the Victoria (Canada) metropolitan area, multimedia campaigns have been targeted at drivers. This paper evaluates the campaign that focused on encouraging left-turning drivers to yield. Observers monitored five signalized intersections during five separate weeks. Logistic regression analyses indicate that this media campaign produced a long-term effect of increasing drivers' yielding behaviors.     

Photophysical processes in poly(hexamethylene adipamide)–acid dye complexes: Energetics of nylon 66 phototendering

The mechanism of dye-sensitized photo-oxidative degradation of nylon 66 was investigated. A known phototendering dye, C.I. Acid Blue 40 (1-amino-4-(p-aminoacetanilide)-2-anthraquinone sodium sulfonate), was used for this study. Excitation and emission spectra of the dyed and undyed nylons indicated that a ground-state complex between the dye and the polyamide was formed upon dyeing. The energy level of the complex's electronic states favor triplet–triplet energy transfer from the nylon to the complex. Quenching studies show that the energy transfer occurs efficiently with a rate constant of 45.8 l. mole^?1 sec^?1. An additional energy transfer occurs between the excited free dye and the complex by either a singlet–triplet or a triplet–triplet mechanism. Kinetic analysis of the nylon-complex energy transfer suggests that the triplet energy of nylon migrates 24 to 33 Å along the amide chromophores in an exciton fashion until an energy trapping complex is reached. Energy is then transferred by an exchange mechanism. Photo-oxidative studies verify that the dye–nylon complex sensitizes the polyamide photo-oxidative degradation at its own expense without dye photobleaching.     

Electric utility rate structures and distributed thermal energy storage: A cost-benefit analysis

We examine three alternative methods by which electric utilities might take advantage of distributed thermal energy storage to smooth out their load profiles. These three methods are: (1) time-specific rates, (2) time-invariant rates with subsidized storage, and (3) direct load controls with no subsidies to storage. The optimal form of each of these policies is determined and relations indicating the relative desirability of each are developed.     

Fourier transform infrared spectroscopic study of transitions above Tg in atactic polystyrene

Fourier transform infrared spectroscopy (FT-IR) has been applied to the study of the molecular mechanisms of transitions of atactic polystyrene above T_g. Intensity measurements of vibrational modes as a function of temperature revealed two transitions above T_g, which are designated as T_u and T′_u. T′_u is independent of molecular weight as opposed to the molecular weight dependent T_u whose behavior is similar to T_g. Infrared measurements are more sensitive to T′_u than T_u. Conformationally sensitive bands show that T′_u may be related to disruption of local order where there is a negligible barrier to conformational change.