Production of free amino acids by some earthworm-borne microorganisms

Production of free amino acids by some earthworm-borne microorganisms was investigated in three different synthetic media. Among the fungi tried Gliocladium roseum and Heterocephallum aurantiacum; among bacteria screened Bacillus macerans and B. mycoides; and among actinomycetes tested Streptomyces rimosus, S. violans, S. antibiticus, S. corchorusii and S. atroolivaceus produced significant amount of free amino acids. No correlations could be observed between vegetative growth and free amino acid production.

Evaluation of Community Care Network (CCN) system in a rural health care setting

Concurrent Engineering Research Center (CERC), under the sponsorship of NLM (National Library of Medicine) is in the process of developing a computerized patient record system for a clinical environment distributed in rural West Virginia. This realization of the CCN (Community Care Network), besides providing computer-based patient records accessible from a chain of clinics and one hospital, supports collaborative health care processes like referral and consulting. To evaluate the effectiveness of the system, a study was designed and is in the process of being executed. Three surveys were designed to provide subjective measures, and four experiments for collecting objective data. Data collection is taking place in several phases: baseline data are collected before the system is deployed; the process is repeated with minimal changes three, then six months later or as often as new versions of the system are installed. Results are then to be compared, using whenever possible matching techniques (i.e. the preliminary data collected on a provider will be matched with the data collected later on the same provider). Surveys are conducted through questionnaires distributed to providers and nurses and person-to-person interviews of the patients. The time spent on patient-chart related activities is measured by work-sampling, aided by a computer application running on a laptop PC. Information about missing patient record parts is collected by the providers, the frequency by which new features of the computerized system are used will be logged by the system itself and clinical outcome measures will be studied from the results of the clinics' own patient chart audits. Preliminary results of the surveys and plans for the immediate and distant future are discussed at the end of the paper.

Selective membranes for the construction and optimization of an amperometric oxalate enzyme electrode

Oxalate oxidase has been immobilized within a membrane laminate. Integration of the laminate within an amperometric electrode afforded a sensor for determining oxalate via electrochemical oxidation of H2O2 and subsequent current generation. A study of novel poly(vinyl chloride) (PVC) and cellulose acetate (CA) membranes with various outer/inner membrane configurations made it possible to eliminate direct electrochemical interference from species present in urine, typically ascorbate (60-500 mumol l-1), homovanillic acid (40-60 mumol l-1) and oxalate itself (50-500 mumol l-1). Of the membranes studied, only CA and plasticized PVC were found to screen out the direct oxalate electrochemical signal effectively. Cellulose acetate exhibited the best selectivity ratio for H2O2 over urine interference. An outer 0.05 micron pore radius polycarbonate membrane imparted sensor linearity in the narrow range 2-200 mumol l-1 oxalate, which fell below the normal range of oxalate in urine. The application of unplasticized PVC as an outer membrane allowed the sensor to exhibit linear characteristics which extended beyond the clinically relevant range (> 700 mumol l-1). The Michaelis-Menten constant of the immobilized enzyme was measured and found to be 10(-3) mol l-1.

ARTEMIS: a collaborative framework for health care

Patient centered healthcare delivery is an inherently collaborative process. This involves a wide range of individuals and organizations with diverse perspectives: primary care physicians, hospital administrators, labs, clinics, and insurance. The key to cost reduction and quality improvement in health care is effective management of this collaborative process. The use of multi-media collaboration technology can facilitate timely delivery of patient care and reduce cost at the same time. During the last five years, the Concurrent Engineering Research Center (CERC), under the sponsorship of DARPA (Defense Advanced Research Projects Agency, recently renamed ARPA) developed a number of generic key subsystems of a comprehensive collaboration environment. These subsystems are intended to overcome the barriers that inhibit the collaborative process. Three subsystems developed under this program include: MONET (Meeting On the Net)--to provide consultation over a computer network, ISS (Information Sharing Server)--to provide access to multi-media information, and PCB (Project Coordination Board)--to better coordinate focussed activities. These systems have been integrated into an open environment to enable collaborative processes. This environment is being used to create a wide-area (geographically distributed) research testbed under DARPA sponsorship, ARTEMIS (Advance Research Testbed for Medical Informatics) to explore the collaborative health care processes. We believe this technology will play a key role in the current national thrust to reengineer the present health-care delivery system.

Effect of carbon and nitrogen sources on the production of penitrem B by Penicillium aurantiogriseum

Effect of different carbon and nitrogen sources on the production of penitrem B was studied. D-Xylose induced maximum penitrem B production, while melibiose, glycerol, citric acid and succinic acid were poor substrates. Potassium nitrate, L-asparagine, sodium nitrate, glycine, DL-aspartic acid and L-tryptophan supported good production of penitrem B. Conversely zirconyl nitrate, barium nitrate, aluminum nitrate, acetanilide, 4-aminobenzoic acid, 4-nitrobenzoic acid and 4-nitroaniline were toxic and did not even permit the growth of the fungus.

Guaranteed convergence in a class of Hopfield networks

A class of symmetric Hopfield networks with nonpositive synapses and zero threshold is analyzed in detail. It is shown that all stationary points have a one-to-one correspondence with the minimal vertex covers of certain undirected graphs, that the sequential Hopfield algorithm as applied to this class of networks converges in at most 2n steps (n being the number of neurons), and that the parallel Hopfield algorithm either converges in one step or enters a two-cycle in one step. The necessary and sufficient condition on the initial iterate for the parallel algorithm to converge in one step are given. A modified parallel algorithm which is guaranteed to converge in [3n/2] steps ([x] being the integer part of x) for an n-neuron network of this particular class is also given. By way of application, it is shown that this class naturally solves the vertex cover problem. Simulations confirm that the solution provided by this method is better than those provided by other known methods.