Comparison of a new anti-glutamic acid decarboxylase (GAD) enzyme-linked immunosorbent assay (ELISA) with radioimmunoassay methods: a multicenter study

Several methods are available for the measurement of antibodies to glutamic acid decarboxylase (anti GAD). These antibodies are valuable tools for the immunodiagnosis of insulin-dependent (type 1) diabetes mellitus (IDDM) and for the assessment of risk for the future development of IDDM. We here describe a new enzyme-linked immunosorbent assay (ELISA) for the detection of anti-GAD which was tested in a multicenter study. The results of the new anti-GAD ELISA correlate well with those obtained by radioimmunoassays (RIA) and they have a higher sensitivity (69%) and specificity (98%) compared to other anti-GAD enzyme immunoassays as determined in the IDW Proficiency Test Program for the detection of GAD antibodies. The new ELISA is simple and easy to perform, with convenient handling of the reagents. Quantitative and reproducible test results are available within approximately four hours. The new anti-GAD ELISA can be used for large scale population screening to indicate a prediabetic state as well as to diagnose autoimmune diabetes in adults (LADA) and the risk for IDDM in pregnant women with gestational diabetes.     

Blood loss in total hip arthroplasty. Lateral position combined with preservation of the capsule versus supine position combined with capsulectomy

The intraoperative blood loss of 40 uncomplicated primary total hip arthroplasties was studied in a retrospective, matched pair analysis. Half of them were implanted in the supine position after complete excision of the capsule and the other half in the lateral position with preservation of the capsule. The patients were matched for mono- or bilateral procedure. Only one surgeon carried out the operations using the same operative technique and identical prosthesis in both groups. The intraoperative blood loss associated with the lateral position and preservation of the capsule averaged 830 ml and was significantly lower (P = 0.01) than 1165 ml with the supine position and complete capsulectomy. Thus, the intraoperative blood loss can be significantly reduced in primary total hip arthroplasty by choosing the lateral position and preserving the capsule.     

Factoring polynomials using binary representations of finite fields

The factorization of polynomials over finite fields is considered. A new deterministic algorithm is proposed that solves the equal-degree factorization problem by combining Berlekamp's (1970) trace algorithm iterative method with the concept of binary representations of finite fields. The interesting aspects of the new algorithm are its simple structure, the easy proof of its correctness, and its efficiency when an efficient realization of the mapping from the finite field to a binary representation is known. Some results about binary representations of finite fields are derived to show that the new factoring algorithm is also nonasymptotically efficient for every finite field. The only practical drawback may be the precomputation of some constants needed in the binary representation, but several suggestions are given to improve this when more about the finite field is known     

Proportional Service Differentiation in Wireless LANs Using Spacing-based Channel Occupancy Regulation

In this paper, we propose Spacing-based Channel Occupancy Regulation (SCORE) MAC protocol for wireless LANs that provides proportional service differentiation in terms of normalized throughput. As shown by our system model and simulation study, SCORE provides consistent, scalable and adjustable proportional differentiation for any network size, any service class distribution, any node data rate and any packet size. Compared to state-of-the-art prioritized service differentiation schemes like Enhanced Distributed Coordination Function (EDCF), SCORE can quantitatively control the channel sharing between different service classes. Moreover, SCORE obtains significant performance improvements in terms of higher network throughput, higher transmission efficiency, lower medium access delay and lower delay jitter. Dr. Qi Xue is now a senior systems engineer with Qualcomm Inc. since Feb. 2005. Qi Xue is currently a Ph.D. candidate in the department of Electrical and Computer Engineering, University of Massachusetts at Amherst. He received his M.S. degree in Electrical and Information Engineering from Huazhong University of Science and Technology, China, in 2000. His research interests include protocol design and performance analysis in wireless networks. Weibo Gong received his Ph.D degree from Harvard University in 1987, and have been with the Dept. of Electrical and Computer Engineering, University of Massachusetts, Amherst since then. He is also an adjunct professor in the Dept. of Computer Science at the same campus. His major research interests include control and systems methods in communication networks, network security, and network modeling and analysis. He is a receipient of the IEEE Transactions on Automatic Control’s George Axelby Outstanding paper award, an IEEE Fellow, and the Program Committee Chair for the 43rd IEEE Conference on Decision and Control. Aura Ganz received her B.Sc, M.Sc and Ph.D degrees in Computer Science from the Technion in Israel. She is currently an associate professor and Director of the Multimedia Networks Laboratory at the ECE Department, University of Massachusetts at Amherst. She has experience in topics related to all strata of networking technology, from work related to topics in the network infrastructure development to advanced user-space application development for mobile clients. The research results are validated by a combination of analytical, simulation and prototyping tools. She has published a book “Multimedia Wireless Networks: Technologies, Standards and QoS” (Prentice Hall) and authored over one hundred and fifty peer reviewed publications. Dr. Ganz is a senior member of IEEE     

Analysis of optimized plates for buckling

This paper is concerned with the analysis of optimized plates for buckling. The Rayleigh-Ritz technique is used to solve variable thickness rectangular plates. A double sine series is used to represent the lateral displacements and convergence is attained for a six term series. The result yields a buckling load which is 44% higher than that of a uniform thickness plate having the same volume. The plate itself was optimized using variational calculus to obtain the optimality condition which states that the thickness is proportional to the strain energy density and a truncated Fourier series solution (one term) was used to obtain an optimal shape having a critical load 112% higher than the uniform thickness plate.     

Localization of human intestinal defensin 5 in Paneth cell granules

Antibiotic peptides of higher animals include the defensins, first discovered in phagocytic cells but recently also found to be produced by epithelial cells. We biosynthesized recombinant human intestinal defensin 5 (rHD-5) using the baculovirus-insect cell expression system. Since insect cells process defensin incompletely and secrete the precursor proHD-5, we substituted a methionine for an alanine at a likely processing site to allow selective chemical cleavage with cyanogen bromide, and rHD-5 was used to elicit polyclonal antibodies. By the immunoperoxidase-staining technique, the antibodies selectively stained Paneth cells of the normal adult small intestine. Immunogold electron microscopy further localized HD-5 to the Paneth cell secretory granules. Since some defensins exert activity cytotoxic to mammalian cells, we assayed the effect of rHD-5 on the human intestinal cell lines Caco2 and Int407. proHD-5 did not exert cytotoxic activity, and rHD-5 showed only minimal activity against Int407 and was inert against Caco2. Since Paneth cells release their granules adjacent to the mitotic cells of the intestinal crypts, HD could protect this cell population against invasion and parasitization by microbes.     

Tractable analytic models of demand assignment protocols innetworks with arbitrary buffer capacity

The authors introduce analytic models for evaluating demand assignment protocols in realistic finite-buffer/finite-station network configurations. A solution for protocols with gated and nongated service disciplines that enables one to model demand assignment protocols as found, for example, in local and metropolitan area networks and in satellite communication systems is presented. A tractable approximate solution based on linear equations whose number is also linear is given. It is demonstrated that in addition to its computational efficiency, the presented approach does not incur a significant penalty in terms of accuracy