On Ohmic Boundary Conditions for Density-Gradient Theory

Conventional ohmic boundary conditions are shown to be inconsistent with density-gradient (DG) theory. New ohmic conditions that are consistent with DG theory are then derived and illustrated with two device examples. The first example uses a short p-n diode to understand the basic situation while the second treats a MOSFET contact and studies the insulator proximity effect seen at the point/edge where the ohmic contact abuts an insulator.     

Will simulation survive the arrival of intelligent control systems

Intelligent, decision-making control systems are on the horizon. (We are discussing those control systems which can intelligently control an operation, process, etc. without human intervention.) Expert systems, AI, fuzzy systems and object oriented simulation programming technologies provide the vehicles by which these systems can be built.     

Expert system for IE student advisement

Student advising is a key function within an academic environment. An expert system may be used as a first line of response to students' advising needs. The system currently under development, uses hypermedia as the interface between user and hidden expert system routines. Hypermedia allows use of user oriented facilities (icon driven menus, branching following user requests, digitized photographs, video discs, animation, etc). The software architecture chosen is that of a hypergraph with embedded, distributed expert systems.     

ManIS: Manufacturing information systems

Information technology, responsible for data collection, processing, storage, retrieval and distribution has made significant strides in the last decade or so. Unfortunately, manufacturing environments have not kept up with the pace of information technology and have failed to utilize this powerful technology to its fullest extent. Manufacturing environments are plagued with a piece-meal approach to problems that need broad and long-range solutions. What is lacking is a broad, comprehensive and focused approach to integrate information systems within the manufacturing environment. We propose ManIS (Manufacturing Information Systems), a model that provides a strategic framework for planning, designing and integrating information systems in a manufacturing environment.     

Effects of 17 beta-estradiol on serum hormone concentrations and estrous cycle in female Crl:CD BR rats: effects on parental and first generation rats

It has been proposed that short-term activation of the hypothalamo-pituitary adrenal axis, with a consequent increase in the secretion of cortisol, amy disrupt the endocrine events prior to ovulation and thereby impair reproduction in females. We investigated this concept in gilts in which oestrus was detected by introduction to boars, where intense physical contact is possible, or by applying pressure to the back of gilts (back-pressure test) during fence-line exposure to boars, where intense physical contact is prohibited. We expected that there would be a greater release of cortisol and that reproduction would be inhibited in gilts introduced to boars compared to gilts in which the back-pressure test was used. As expected, introduction of gilts to boars resulted in a significant transient increase in plasma concentrations of cortisol while there was no significant effect of using the back-pressure test on plasma cortisol. Nevertheless, introduction of gilts to boars did not impair reproduction and there was no effect of method of detecting oestrus on duration of oestrus, sexual receptivity, fertility or fecundity. The length of the oestrous cycle was decreased and ovulation rate increased in gilts that were introduced to boars compared to gilts that underwent the back-pressure test, indicating that introduction of gilts to boars may have stimulated these aspects of reproduction. These stimulatory effects may have been due to an increased exposure of gilts to sexual behaviour and stimuli from boars when introduced to boars and/or to stimulatory effects of the hypothalamo-pituitary adrenal axis on some aspects of reproduction.     

The future of artificial intelligence (AI) in manufacturing

Artificial Intelligence (AI) is now among the buzzwords in manufacturing. Articles are written about various aspects of AI in manufacturing and some of these are discussed by Miller in “Artificial Intelligence: Applications for Manufacturing” [1]. Most of those authors extol the virtues of AI in manufacturing. From some of the literature, one might draw the conclusion that AI will solve all of our problems.

AI technologies are very sophisticated and are not going to easily accomodate the “noise” of the factory floor. We can see some of these techniques beginning to make inroads into manufacturing, but the road to full-scale implementation will be a rocky one.     

A rapid and sensitive radioimmunoassay for the detection of human cytomegalovirus binding and infection of human fibroblasts

A rapid and sensitive radioimmunoassay for the quantitation of HCMV binding and infection of human fibroblasts (HFF) was developed. The protocol involves the use of a monoclonal antibody (27-156) reactive with HCMV gB (alpha-gB), followed by an 125I-labeled second antibody to mouse IgG. Antibody to gB bound specifically to HFF inoculated with HCMV when compared to sham inoculated cells or cells inoculated with HSV (strain KOS). Antibody to gB also bound to HFF infected with HCMV 48 h prior to assay. The binding of antibody to HFF inoculated with HCMV was found to be dependent on antibody concentration and to demonstrate saturable kinetics. Moreover, antibody binding was directly dependent on the concentration of the virus inoculum, using either conventional viral preparations or gradient purified HCMV. The binding of antibody to HFF inoculated with HCMV at 4 degrees C was found to be dependent on antibody concentration and to demonstrate saturable kinetics. Displacement of HCMV binding to HFF with the proteoglycan heparin sulfate could be detected, thus allowing for competitive binding studies. This binding assay allows for the relative quantitation of HCMV binding to cells and will be useful for examining the early events of cell-viral interactions.     

Beta-actin mRNA-binding proteins associated with the cytoskeletal framework

Association of mRNA with the cytoskeletal framework (CSK) is thought to play a strategic role in the placement of mRNA in the cytoplasm. However, the molecular determinants underlying mRNA/CSK association are completely unknown. To begin addressing this issue, we have employed a binding assay to identify proteins of the CSK compartment of NIH 3T3 cells that bind in-vitro-transcribed 32P-labelled beta-actin mRNA with high affinity. Three proteins, of approximate molecular masses 27, 50 and 97 kDa, were observed to exhibit strong binding. Binding to these proteins took place at physiological salt concentration and withstood washing in 0.5 M salt. Furthermore, binding was unaffected by heparin but was inhibited by unlabelled beta-actin mRNA. Treatment of isolated CSKs with the microfilament-severing agent DNase I abolished all beta-actin mRNA-binding activities, thus suggesting a possible association of beta-actin mRNA with the microfilament network in situ. Removal of the 3' untranslated region (UTR) significantly reduced beta-actin mRNA binding to all three CSK proteins but removal of the 5' UTR mainly affected binding to the 97-kDa species and that to a lesser extent. beta-Tubulin mRNA bound to the same three CSK proteins as did beta-actin mRNA, but with considerably less avidity. In contrast, vimentin mRNA strongly recognized these CSK proteins, and further bound to a group of smaller proteins (< 29 kDa). As beta-actin mRNA, beta-tubulin mRNA and vimentin mRNA have been observed to occupy separate cytoplasmic locales, the proteins detected here may be operative both in binding mRNAs to the CSK in situ, as well as in localizing mRNA in the cytoplasm.