Study of adenovirus production in serum-free 293SF suspension culture by GFP-expression monitoring

BACKGROUND: Recently, investigators have reported the use of endoscopic myotomy in the treatment of esophageal achalasia. As with the open operation, considerable disagreement exists regarding the appropriate length of the myotomy and the need for a concomitant antireflux procedure. METHODS: Patients presenting with symptomatic achalasia between 1993 and 1997 were included in this prospective study. Preoperative studies included barium upper gastrointestinal study, endoscopy, and esophageal manometry. Laparoscopic myotomy was completed in all 20 patients; 18 had concomitant Toupet fundoplication. RESULTS: Operative times ranged from 95 to 345 minutes (mean 216). Blood loss ranged from 50 to 300 cc (mean 100 cc). There were 7 minor complications (5 mucosal injuries repaired laparoscopically, 1 bile leak and 1 splenic capsular tear). Nine patients began a liquid diet on the first day postoperatively; 19 were tolerating liquids by postoperative day 3. Hospital stay ranged from 2 to 20 days (mean 5). Eighteen patients had complete relief of dysphagia, with less than one reflux episode per month. One individual continues to have mild persistent solid food dysphagia. Another patient initially did well but subsequently developed mild recurrent dysphagia and reflux. One patient required laparoscopic take-down of the wrap because of recurrent dysphagia and now has no problems swallowing, but does complain of mild reflux. Two other patients also have mild reflux, 1 of whom did not undergo fundoplication. CONCLUSIONS: Laparoscopic Heller myotomy can be performed safely with excellent results in patients with achalasia. Adding a partial fundoplication appears to help control postoperative symptoms of reflux. This procedure should be considered the procedure of choice in patients with symptomatic esophageal achalasia.     

On projection methods,convergence and robust formulations in topology optimization

Mesh convergence and manufacturability of topology optimized designs have previously mainly been assured using density or sensitivity based filtering techniques. The drawback of these techniques has been gray transition regions between solid and void parts, but this problem has recently been alleviated using various projection methods. In this paper we show that simple projection methods do not ensure local mesh-convergence and propose a modified robust topology optimization formulation based on erosion, intermediate and dilation projections that ensures both global and local mesh-convergence.     

On the implementation of bytecode compression for interpreted languages

This paper describes a new method for code space optimization for interpreted languages called LZW‐CC . The method is based on a well‐known and widely used compression algorithm, LZW , which has been adapted to compress executable program code represented as bytecode. Frequently occurring sequences of bytecode instructions are replaced by shorter encodings for newly generated bytecode instructions. The interpreter for the compressed code is modified to recognize and execute those new instructions. When applied to systems where a copy of the interpreter is supplied with each user program, space is saved not only by compressing the program code but also by automatically removing the unused implementation code from the interpreter. The method's implementation within two compiler systems for the programming languages Haskell and Java is described and implementation issues of interest are presented, notably the recalculations of target jumps and the automated tailoring of the interpreter to program code. Applying LZW‐CC to nhc98 Haskell results in bytecode size reduction by up to 15.23% and executable size reduction by up to 11.9%. Java bytecode is reduced by up to 52%. The impact of compression on execution speed is also discussed; the typical speed penalty for Java programs is between 1.8 and 6.6%, while most compressed Haskell executables run faster than the original. Copyright © 2008 John Wiley & Sons, Ltd.     

A local linearized least squares algorithm for training feedforwardneural networks

In training the weights of a feedforward neural network, it is well known that the global extended Kalman filter (GEKF) algorithm has much better performance than the popular gradient descent with error backpropagation in terms of convergence and quality of solution. However, the GEKF is very computationally intensive, which has led to the development of efficient algorithms such as the multiple extended Kalman algorithm (MEKA) and the decoupled extended Kalman filter algorithm (DEKF), that are based on dimensional reduction and/or partitioning of the global problem. In this paper we present a new training algorithm, called local linearized least squares (LLLS), that is based on viewing the local system identification subproblems at the neuron level as recursive linearized least squares problems. The objective function of the least squares problems for each neuron is the sum of the squares of the linearized backpropagated error signals. The new algorithm is shown to give better convergence results for three benchmark problems in comparison to MEKA, and in comparison to DEKF for highly coupled applications. The performance of the LLLS algorithm approaches that of the GEKF algorithm in the experiments.     

Design issues of a distance learning course on Business on the Internet

Abstract The paper presents the main design issues of a distance learning course on Business on the Internet. The instructional design is based on a learner-centred instructional strategy which allows learners to construct their own knowledge while solving real business problems and transferring their knowledge to other learners. They learn autonomously taking the responsibility for their learning and following their individual cognitive styles, interests, preferences. The learners have access to the Internet being members of a global, cooperative learning community. The learning community involves students and tutors who collectively take responsibility for the design and evaluation of the course content and the teaching methods to be applied. Both students and tutors inhabit a virtual learning environment that offers different virtual places and services: virtual university, virtual enterprise, auditoriums, workshop rooms, cafes, libraries, etc. where students from different locations can meet, interact, learn and work together, as if they were face-to-face.     

Comparison of the fatty acids of the tunicateBotryllus schlosseri from the Black Sea with two associated bacterial strains

The fatty acid composition of the tunicateBotryllus schlosseri and of two bacterial strains found within the tunicate, namelyVibrio parahaemolyticus and of an associated but previously unreported gram positive cocci were studied. The polyunsaturated fatty acids 6,9,12-octadecatrienoic acid, 5,8,11,14,17-eicosapentaenoic acid, and 4,7,10,13,16,19-docosahexaenoic acid were particularly abundant inB. schlosseri and were not detected in the two bacterial strains found in the tunicate. Theiso/anteiso pair, 13-methyltetradecanoic acid and 12-methyltetradecanoic acid, were the principal fatty acids in the gram positive cocci, and the 9- and 11-hexadecenoic acids were particulary abundant inV. parahaemolyticus. The diunsaturated fatty acid 9,12-octadecadienoic acid was also shown to be present inV. parahaemolyticus. The fatty acid composition of a third bacterial strain, characterized as either aPseudomonas or anAlteromonas species, and shown to be present only in the sea water from the Black Sea and not inB. schlosseri, is also reported. This is the first investigation on fatty acids from Black Sea bacteria.     

Monitoring motility, spreading, and mortality of adherent insect cells using an impedance sensor

An emerging sensor technology referred to as electric cell-substrate impedance sensing (ECIS) has been extended for monitoring the behavior of insect cells including attachment, motility, and mortality. In ECIS, adherent cells were cultured on an array of eight small gold electrodes deposited on the bottom of tissue culture wells and immersed in a culture medium. Upon the attachment and spreading of cells on the gold electrode, the impedance increased because the cells acted as insulating particles to restrict the current flow. Experimental data revealed that insect cells interacted differently with various proteins used to precoat the gold electrode with concanavalin A as the best promoter to accelerate the rate of cell attachment. After the cells were fully spread, the measured impedance continued to fluctuate to reflect the constant motion and metabolic activity of the cells. As the cell behavior was sensitive to external chemicals, the applicability of ECIS for inhibition assays was demonstrated with HgCl2, trinitrotoluene, trinitrobenzene (TNB), and 2-amino-4,6-dinitrotoluene as model systems. Unlike conventional assays, the quantitative data obtained in this study are taken in real time and in a continuous fashion to depict cell motility and mortality.     

Expert system classification of urban land use/cover for Delhi,India

This study presents the results of classifying land use/land cover for Delhi, India using an expert system approach. For this study Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data of 22 September 2003 were used. The research goals of this project are two‐fold. In one respect, the research goal is to report on the extent covered by urbanization using the classified image. Thirteen different land‐cover categories were identified with an 85.55% overall classification accuracy based on 256 random points for validation and 50 on the ground observations. Secondly, we report on our efforts to duplicate an expert system model previously developed for Phoenix Arizona as a generalized approach for urban land use classification. Results suggest that while some of the methodology could be duplicated, there are local factors (e.g. data availability and specific land features) that required the approach to be modified.