SUMMARYThe purpose of this paper is to provide a quick overview of neural networks and to explain how they can be used in control systems. We introduce the multilayer perceptron neural network and describe how it can be used for function approximation. The backpropagation algorithm (including its variations) is the principal procedure for training multilayer perceptrons; it is briefly described here. Care must be taken, when training perceptron networks, to ensure that they do not overfit the training data and then fail to generalize well in new situations. Several techniques for improving generalization are discussed. The paper also presents three control architectures: model reference adaptive control, model predictive control, and feedback linearization control. These controllers demonstrate the variety of ways in which multilayer perceptron neural networks can be used as basic building blocks. We demonstrate the practical implementation of these controllers on three applications: a continuous stirred tank reactor, a robot arm, and a magnetic levitation system.

CST (BART BARF0) family viral RNAs are expressed in several types of Epstein-Barr virus (EBV) infection, including EBV-associated cancers.Many different spliced forms of these RNAs have been described; here we have clarified the structures of some of the more abundant splicing patterns. We report the first cDNAs representing a full-length CST mRNA from a clone library and further characterize the transcription start. The relative abundance of splicing patterns and genomic analysis of the open reading frames (ORFs) suggest that, in addition to the much studied BARF0 ORF, there may be important products made from some of the upstream ORFs in the CST RNAs. Potential biological functions are identified for two of these. The product of the RPMS1 ORF is shown to be a nuclear protein that can bind to the CBF1 component of Notch signal transduction. RPMS1 can inhibit the transcription activation induced through CBF1 by NotchIC or EBNA-2. The protein product of another CST ORF, A73, is shown to be a cytoplasmic protein which can interact with the cell RACK1 protein. Since RACK1 modulates signaling from protein kinase C and Src tyrosine kinases, the results suggest a possible role for CST products in growth control, perhaps consistent with the abundant transcription of CST RNAs in cancers such as nasopharyngeal carcinoma.In several types of infection, in addition to the well-established EBNA, LMP and EBER genes, Epstein-Barr virus (EBV) has been found to express various spliced RNAs transcribed rightward from the region spanning 150,000 to 161,000 on the B95-8 EBV genetic map. These have been referred to as complementary strand transcripts (CSTs), BamHI A rightward transcripts (BARTs), or the BARF0 RNAs. RNAs of this type were originally identified in cDNA made from the C15 xenograft culture of nasopharyngeal carcinoma (NPC) tissue (17). Similar RNAs were subsequently found in various EBV-positive NPC tumor biopsies and xenografts, Burkitt's lymphoma, lymphoid cell lines (LCLs) (3,6,11,15,19,31,43), and biopsies of oral hairy leukoplakia (24). Expression of CST RNAs has also been demonstrated in peripheral blood of normal human carriers of EBV (5), sera from NPC patients have been found to immunoprecipitate a protein product of the BARF0 open reading frame (ORF) made in vitro (12), and cytotoxic T lymphocytes that respond to a peptide derived from BARF0 have been identified in EBV-infected people (22).A very complicated picture of alternatively spliced CST RNAs has built up (36, 38), but some of the proposed structures have been deduced using very sensitive reverse transcription (RT)-PCR methods or have been only single isolates from cDNA libraries, and thus they may yet represent very minor species within the family of RNAs that can be expressed. Predominant sizes of the RNAs expressed have been deduced from Northern blots, but these have only partly been related to the spliced RNA structures. In addition, the coding content of the CST RNAs remains uncertain. Most attention has focused on the BARF0 ORF, particularly a sp...

Calreticulin is an endoplasmic reticulum resident molecule known to be involved in the folding and assembly of major histocompatibility complex (MHC) class I molecules. In the present study, expression of calreticulin was analyzed in human peripheral blood T lymphocytes. Pulse-chase experiments in [35 S]methionine-labeled T cell blasts showed that calreticulin was associated with several proteins in the endoplasmic reticulum and suggested that it was expressed at the cell surface. Indeed, the 60-kDa calreticulin was labeled by cell surface biotinylation and precipitated from the surface of activated T cells together with a protein with an apparent molecular mass of 46 kDa. Cell surface expression of calreticulin by activated T lymphocytes was further confirmed by immunofluorescence and flow cytometry, studies that showed that both CD8؉ and CD4؉ T cells expressed calreticulin in the plasma membrane. Low amounts of cell surface calreticulin were detected in resting T lymphocytes. By sequential immunoprecipitation using the conformation independent monoclonal antibody HC-10, we provided evidence that the cell surface 46-kDa protein co-precipitated with calreticulin is unfolded MHC I. These results show for the first time that after T cell activation, significant amounts of calreticulin are expressed on the T cell surface, where they are found in physical association with a pool of ␤ 2 -free MHC class I molecules.Calreticulin is a highly conserved and widely tissue distributed calcium-binding protein with a C-terminal KDEL endoplasmic reticulum (ER) 1 retrieval sequence (1-3). However, calreticulin has also been found outside the ER, such as within the secretory granules of cytotoxic lymphocytes, the cell surface of melanoma cells and virus-infected fibroblasts, and the cytosol and nucleus of several cell types reviewed in Ref. 9). Given its lectin-like properties, calreticulin is considered to be an ER chaperone involved in the assembly and folding of nascent glycoproteins (10 -13).Mature MHC class I molecules are composites of a 44 -49-kDa polymorphic heavy chain and a 12-kDa light chain (␤ 2 m) complexed with a cytosolic-processed peptide that are expressed on the plasma membrane of almost every nucleated cell (14). A number of ER resident molecular chaperones, such as calnexin, BiP, and transporter-associated protein, are involved in the assembly of the different composites (15)(16)(17)(18). Recently, calreticulin has also been shown to function as a chaperone in the assembly and folding of MHC class I molecules in the ER (19 -22). Contrary to calnexin, calreticulin binds to MHC class I-␤ 2 m dimers and to transporter-associated protein via another chaperone, tapasin (19,21). After peptide loading and deglucosylation of N-linked glycans, calreticulin dissociates from the MHC class I-␤ 2 m dimers, thus allowing the final transport of mature MHC class I molecules to the cell surface (20).Recent studies on the biosynthesis of TcR⅐CD3 complexes suggest that some chaperones such as calnexin can escape the ER retent...

Surgery for meningiomas involving the cavernous sinus seems to provide excellent tumor control. Our experience suggests that for the majority of these tumors, complete tumor resection can be performed with acceptable risks of morbidity and mortality and seems to increase the duration of recurrence-free survival. The long-term quality of life of surviving patients is satisfactory, with the great majority of the patients being independent.