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PubMed1997

Common Optimization of Adaptive Preprocessing Units and a Neural Network during the Learning Period. Application in EEG Pattern Recognition.

In this study, a proposition of simultaneous training of the neural network (multilayer perceptron) and adaptive preprocessing unit is presented. This cooperation enables the network to affect the preprocessing and as a consequence to vary the locations of pattern vectors in a feature space. Thus, during the learning process the network tries to find a good separation of classes of patterns, which results in convergence of the whole learning process. The strategy was developed in order to make efficient EEG monitoring in neonates possible. A comparison of the method presented herein with the known learning strategies for neural networks shows the need for using it as an alternative learning process. The convergence of the whole system is also discussed. Copyright 1997 Elsevier Science Ltd.

Journal Article↗
PubMed1998

What is done, what is needed and what is realistic to expect from medical informatics standards.

Medical informatic experts have made considerable progress in the development of standards for orders and clinical results (CEN, HL7, ASTM), EKG tracings (CEN), diagnostic images (DICOM), claims processing (X12 and EDIFAC) and in vocabulary and codes (SNOMED, Read Codes, the MED, LOINC). Considerable work still remains to be carried out. Abstract models of health care information have to be created, to cover the necessary domain, and yet be simple enough to assimilate, implement, and manage. This requires a high degree of abstraction. Enormous amounts to develop standardized vocabulary are still required to complement such a model, and to define the subsets that apply to given contexts.

Computer Communication Networks↗
PubMed2006

Microbioreactor arrays with integrated mixers and fluid injectors for high-throughput experimentation with pH and dissolved oxygen control.

We have developed an integrated array of microbioreactors, with 100 microL working volume, comprising a peristaltic oxygenating mixer and microfluidic injectors. These integrated devices were fabricated in a single chip and can provide a high oxygen transfer rate (k(L)a approximately 0.1 s(-1)) without introducing bubbles, and closed loop control over dissolved oxygen and pH (+/-0.1). The system was capable of supporting eight simultaneous Escherichia coli fermentations to cell densities greater than 13 g-dcw L(-1) (1 cm OD(650 nm) > 40). This cell density was comparable to that achieved in a 4 litre reference fermentation, conducted with the same strain, in a bench scale stirred tank bioreactor and is more than four times higher than cell densities previously achieved in microbioreactors. Bubble free oxygenation permitted near real time optical density measurements which could be used to observe subtle changes in the growth rate and infer changes in the state of microbial genetic networks. Our system provides a platform for the study of the interaction of microbial populations with different environmental conditions, which has applications in basic science and industrial bioprocess development. We leverage the advantages of microfluidic integration to deliver a disposable, parallel bioreactor in a single chip, rather than robotically multiplexing independent bioreactors, which opens a new avenue for scaling small scale bioreactor arrays with the capabilities of bench scale stirred tank reactors.

Ammonium Hydroxide↗
PubMed2000

From image segmentation to anti-textons.

We apply the 'patchwork engine' (PE; van Tonder and Ejima, 2000 Neural Networks forthcoming) to encode spaces between textons in an attempt to find a suitable feature representation of anti-textons [Williams and Julesz, 1991, in Neural Networks for Perception volume 1: Human and Machine Perception Ed. H Wechsler (San Diego, CA: Academic Press); 1992, Proceedings of the National Academy of Sciences of the USA 89 6531-6534]. With computed anti-textons it is possible to show that tessellation and distribution of anti-textons can differ from that of textons depending on the ratio of texton size to anti-texton size. From this we hypothesise that variability of anti-textons can enhance texture segregation, and test our hypothesis in two psychophysical experiments. Texture segregation asymmetry is the topic of the first test. We found that targets on backgrounds with regular anti-textons segregate more strongly than on backgrounds with highly variable anti-textons. This neatly complements other explanations for texture segregation asymmetry (e.g. Rubenstein and Sagi, 1990 Journal of the Optical Society of America A 7 1632-1643). Second the relative significance of textons and anti-textons in human texture segregation is investigated for a limited set of texture patterns. Subjects consistently judged a combination of texton and anti-texton gradients as more conspicuous than texton-only gradients, and judged texton-only gradients as being more conspicuous than anti-texton-only gradients. In the absence of strong texton gradients the regularity versus irregularity of anti-textons agrees with perceived texture segregation. Using PE outputs as anti-texton features thus enabled the conception of various useful tests on texture segregation. The PE is originally intended as a general image segmentation method based on symmetry axes. With this paper we therefore hope to relate anti-textons with visual processing in a wider sense.

Contrast Sensitivity↗
PubMed2004

Capacity of oscillatory associative-memory networks with error-free retrieval.

Networks of coupled periodic oscillators (similar to the Kuramoto model) have been proposed as models of associative memory. However, error-free retrieval states of such oscillatory networks are typically unstable, resulting in a near zero capacity. This puts the networks at disadvantage as compared with the classical Hopfield network. Here we propose a simple remedy for this undesirable property and show rigorously that the error-free capacity of our oscillatory, associative-memory networks can be made as high as that of the Hopfield network. They can thus not only provide insights into the origin of biological memory, but can also be potentially useful for applications in information science and engineering.

Association↗
PubMed2005

An algebraic geometry approach to protein structure determination from NMR data.

Our paper describes the first provably-efficient algorithm for determining protein structures de novo, solely from experimental data. We show how the global nature of a certain kind of NMR data provides quantifiable complexity-theoretic benefits, allowing us to classify our algorithm as running in polynomial time. While our algorithm uses NMR data as input, it is the first polynomial-time algorithm to compute high-resolution structures de novo using any experimentally-recorded data, from either NMR spectroscopy or X-Ray crystallography. Improved algorithms for protein structure determination are needed, because currently, the process is expensive and time-consuming. For example, an area of intense research in NMR methodology is automated assignment of nuclear Overhauser effect (NOE) restraints, in which structure determination sits in a tight inner-loop (cycle) of assignment/refinement. These algorithms are very time-consuming, and typically require a large cluster. Thus, algorithms for protein structure determination that are known to run in polynomial time and provide guarantees on solution accuracy are likely to have great impact in the long-term. Methods stemming from a technique called "distance geometry embedding" do come with provable guarantees, but the NP-hardness of these problem formulations implies that in the worst case these techniques cannot run in polynomial time. We are able to avoid the NP-hardness by (a) some mild assumptions about the protein being studied, (b) the use of residual dipolar couplings (RDCs) instead of a dense network of NOEs, and (c) novel algorithms and proofs that exploit the biophysical geometry of (a) and (b), drawing on a variety of computer science, computational geometry, and computational algebra techniques. In our algorithm, RDC data, which gives global restraints on the orientation of internuclear bond vectors, is used in conjunction with very sparse NOE data to obtain a polynomial-time algorithm for protein structure determination. An implementation of our algorithm has been applied to 6 different real biological NMR data sets recorded for 3 proteins. Our algorithm is combinatorially precise, polynomial-time, and uses much less NMR data to produce results that are as good or better than previous approaches in terms of accuracy of the computed structure as well as running time. In practice approaches such as restrained molecular dynamics and simulated annealing, which lack both combinatorial precision and guarantees on running time and solution quality, are commonly used. Our results show that by using a different "slice" of the data, an algorithm that is polynomial time and that has guarantees about solution quality can be obtained. We believe that our techniques can be extended and generalized for other structure-determination problems such as computing side-chain conformations and the structure of nucleic acids from experimental data.

Algorithms↗
PubMed2004

Modeling infection transmission.

Understanding what determines patterns of infection spread in populations is important for controlling infection transmission. The science that advances this understanding uses mathematical and computer models that vary from deterministic models of continuous populations to models of dynamically evolving contact networks between individuals. These provide insight, serve as scientific theories, help design studies, and help analyze data. The key to their use lies in assessing the robustness of inferences made using them to violation of their simplifying assumptions. This involves changing model forms from deterministic to stochastic and from compartmental to network, as well as adding realistic detail and changing parameter values. Currently inferences about infection transmission are often made using stratified rate or risk comparisons, logistic regression models, or proportionate hazards models that assume an absence of transmission. Robustness assessment will show many of these inferences to be wrong. A community of epidemiologist modelers is needed for effective robustness assessment.

Data Interpretation, Statistical↗
PubMed2006

Outstanding scientist of the year 2006: Rogel Patawaran, BS.

Rogel Patawaran is cofounder of iQSecure Solutions, Inc., a secure web mail company, which began in 2002 and is currently based in Santa Monica, California. Its unique service enables hospitals, clinics, and doctors' offices the opportunity to have secure web-based video and telephone conferencing by simply switching online services offered by this innovative company. In addition, he is cofounder of AuthoTecq, based in Long Beach, California, and inventor of the AuthoTecq system in 1999. The AuthoTecq system is an online credit card processing company. Rogel Patawaran sought to remedy one of the problems facing users of internet transactions. Because internet merchants act as their own gateway for financial transactions, they have been storing credit card numbers in their own databases, thereby failing to address the necessary security provisions involved in the storage of such sensitive information. AuthoTecq removes this responsibility from the merchant by processing financial transactions on behalf of the merchants. Its system dramatically reduces credit card theft, and thereby decreases the amount of credit card fraud. In his landmark book Saving Lives & Saving Money, Newt Gingrich, former Speaker of House of Representatives, describes a new approach to the challenge of creating a better system of personal health and health care for the 21st century, a system that saves lives and saves money. He indicates that you could be visiting a clinic with electronic medical records, electronic laboratory reports, and electronic drug prescriptions. This entirely electronic clinic saves money and lives because it is far more accurate than a paper system. Such clinics exist at the Kaiser Permanente Hospitals, the Mayo Clinic in Jacksonville, Florida, the Cleveland Clinic, many Harvard hospitals, and all Veteran Administration hospitals in the US. He indicates that healthcare is the only industry in America that can give you a disease and then charge you to cure it. He further reports that out of 100 hospital patients, five or six will be the victim of a preventable error. He states that medication errors alone kill 7000 people each year, adding $2 billion to the overall cost of healthcare. He stresses that these 7000 needless deaths are not only unacceptable but un-American as well. During the 1990s, the pharmaceutical industry sought help from the Food and Drug Administration (FDA) to develop a standard by which a paperless system could be adopted for healthcare. In March of 1997, the FDA issued its final ruling, which established the criteria for which the FDA will recognize the transmission of authenticity within electronic data as well as establishing standards of authenticity for electronic data equivalent to the validity of signatures on paper documents and records. The FDA also recognizes the growth that can be experienced by converting healthcare technology to a paperless system, such as the expediting of patient files in a more organized manner, increasing the speed of file transfer of such documents, reducing prescription errors, enabling computer-generated data analysis and statistics, and reducing storage space. Rogel Patawaran and his colleagues also realized that electronic healthcare technology using the highest standard of data encryption to transfer data could also dramatically improve the safety of patients in our nation and the world. To answer the needs within healthcare technology, Rogel Patawaran created a system for healthcare providers using the most superior encryption methods, and in the process creating iQSolutions, Inc. Its web mail system uses the Public Key Infrastructure (PKI) format, which is the strongest known encryption format. PKI is used in combination with the Advance Encryption Standard (AES) digital encryption algorithm, which is the current algorithm used by banks and government agencies, thereby protecting the privacy and accuracy of the information. Rogel Patawaran's remarkable contributions to the encryption process will aid in the number of lives saved as well as helping to avoid medical malpractice by ensuring the accuracy of medical records, as well as reducing the number of medication errors or inappropriate prescriptions being filled. These remarkable accomplishments in patient safety are accomplished at a rapid speed that ensures that data-sensitive patient files can be securely transmitted between and within hospitals. Finally, with the growing need for an electronic system within the medical field, doctors will be able to securely access all such data from anywhere and at any time, thus reducing the age-old problem of time constraints that a paper system presented doctors and hospitals alike. In recognition of Rogel Patawaran's contributions to the medical field through the use of encryption teamed with the transferring of sensitive data such as hospital records, Rogel Patawaran has been selected as the Outstanding Scientist of 2006.

Artificial Intelligence↗
PubMed2002

Bacterial and fungal aerosols in indoor environment in Central and Eastern European countries.

Studies of indoor bioaerosols conducted in Central and Eastern European countries, as a result of the scarcity of funding, mostly do not attain the level presented by similar studies in Northern America and Western Europe. For socio-economic reasons, most of the intense studies on indoor bioaerosols in Central and Eastern European countries were carried out in industrial facilities and have contributed significantly to occupational health science. In contrast, until recently, insufficient of studies have been conducted on bioaerosols of residential and communal premises (dwellings, offices, schools, etc.) and no network for monitoring the microbiological quality of air in such premises exists. In Poland, in the mid-1990s complex bioaerosol investigations were carried out by the Bioaerosol Group at the Institute of Occupational Medicine and Environmental Health in Sosnowiec. The concentrations of airborne bacteria and fungi in dwellings without mold problems were between 88-4297 cfu/m(3) and 0-1997 cfu/m(3), while in moldy homes they were 178-4751 cfu/m(3) and 49-16,968 cfu/m(3), respectively. As many as 167 microbial species were isolated from the air of examined dwellings. Most frequently occurred Gram-positive cocci (Micrococcus/ Kocuria spp., Staphylococcus spp.), endospore-forming bacilli (Bacillus spp.), Gram-negative bacteria (Pseudomonadaceae, Aeromonas spp.), filamentous fungi (Penicillium spp., Aspergillus spp.), and yeasts. Notable studies of indoor bioaerosols have also been performed in the other Central and Eastern European countries: Lithuania, Latvia, Estonia, Russian Federation, Ukraine, Czech Republic, Slovakia, Bulgaria and Hungary, are reviewed in this article. The lack of reference limit values for bioaerosols seriously hinders interpretation of results obtained in various countries. The following residential limit values (RLV) for dwellings and communal premises are proposed for the concentration of airborne bacteria, fungi and bacterial endotoxin: 5 x 10(3) cfu/m(3), 5 x 10(3) cfu/m(3) and 5 ng/m(3) (50 EU), respectively. The proposed values of occupational exposure limit (OEL) for industrial settings contaminated by organic dust are 100 x (3) cfu/m(3), 50 x (3) cfu/m(3) and 200 ng/m(3) (2000 EU), respectively. It is also proposed that the presence in indoor air of microorganisms from risk groups 3 and 4 of European Community Directive 2000/54/EC (e.g., Mycobacterium tuberculosis, Bacillus anthracis, Coxiella burnetii), independently of the concentration, should always be inadmissible and result in preventive actions.

Aerosols↗
PubMed2004

Web usage mining at an academic health sciences library: an exploratory study.

OBJECTIVES: This paper explores the potential of multinomial logistic regression analysis to perform Web usage mining for an academic health sciences library Website. METHODS: Usage of database-driven resource gateway pages was logged for a six-month period, including information about users' network addresses, referring uniform resource locators (URLs), and types of resource accessed. RESULTS: It was found that referring URL did vary significantly by two factors: whether a user was on-campus and what type of resource was accessed. CONCLUSIONS: Although the data available for analysis are limited by the nature of the Web and concerns for privacy, this method demonstrates the potential for gaining insight into Web usage that supplements Web log analysis. It can be used to improve the design of static and dynamic Websites today and could be used in the design of more advanced Web systems in the future.

Academic Medical Centers↗
PubMed1997

Common ground: the HealthWeb project as a model for Internet collaboration.

The establishment of the HealthWeb project by twelve health sciences libraries provides a collaborative means of organizing and enhancing access to Internet resources for the international health sciences community. The project is based on the idea that the Internet is common ground for all libraries and that through collaboration a more comprehensive, robust, and long-lasting information product can be maintained. The participants include more than seventy librarians from the health sciences libraries of the Committee on Institutional Cooperation (CIC), an academic consortium of twelve major research universities. The Greater Midwest Region of the National Network of Libraries of Medicine serves as a cosponsor. HealthWeb is an information resource that provides access to evaluated, annotated Internet resources via the World Wide Web. The project vision as well as the progress reported on its implementation may serve as a model for other collaborative Internet projects.

Computer Communication Networks↗
PubMed2005

[Instruments for patient-reported outcomes and predictors in German-speaking rehabilitation research--current developments within the "Rehabilitation Sciences" research funding programme].

In 1998, the German Federal Ministry of Education and Research (BMBF) and the German pension insurance scheme established a funding programme for research in rehabilitation. This initiative led to the establishment of eight regional research networks in which numerous research projects were sponsored for eight years (1998-2005). Within the framework of this funding programme, various self-assessment instruments were developed, adapted or improved in order to measure patient-reported outcomes and predictors. In sum, the analyses meet high psychometric standards. In this paper, a comprehensive review is given in five important assessment fields of rehabilitation research in Germany: Health-related quality of life (generic, disease-specific, children and adolescents, preference-based), evaluation of specific therapy and education programmes, motivation, screening for vocational problems and screening for comorbid mental disorders. The instruments are critically discussed, and perspectives for further research are pointed out.

Biomedical Research↗
PubMed1991

The International Clinical Epidemiology Network (INCLEN): a progress report.

The International Clinical Epidemiology Network (INCLEN) was established in 1982 to strengthen the research capacity of medical schools in the developing world through the development of Clinical Epidemiology Units (CEUs). The role of these units is to promote a rational approach to clinical and health care decision making, drawing on the methods of clinical epidemiology, biostatistics, health economics and health social science. This paper summarizes the evolution of the INCLEN model and the experience to date. Progress with Phase 1, the designation of sites for CEU development and the provision of advanced research training by developed country training centres has been substantial. The network now consists of 27 units: 26 in developing country medical schools in Asia, Latin America, India and Africa and 1 in France. More than 60% of the target of 270 fellows have completed training and returned to take up faculty positions in their unit. The remainder will be trained and on site by 1995. The non-return rate of fellows (2%) is very low. Research productivity is significant given only 60 fellows have been working in their CEUs for more than 3 years following the completion of training. An appropriate balance between hospital and community-based research is evident and changes in clinical and health care policy have been made based on the research conducted. The educational responsibilities of all units include courses and workshops in critical appraisal and clinical epidemiology for medical trainees and colleagues. Graduate training programs have emerged in 3 units so far. Major challenges lie ahead as we move into Phase 2 of the project--self sustainability and the transfer of training responsibility to the CEUs. The problems encountered during Phase 1 will need to be addressed. These include time protection for research, the limited availability of research funds, the low priority given to research careers and the poor linkage between health researchers and government policy makers. Our experience echos the recommendations of the recent report of the Commission on Health Research for Development, namely that donors and national governments should give increased priority to the role of health research in less developed countries. We conclude that with continuing support and special attention to the problems encountered, the INCLEN approach can contribute to ensuring that the medical establishment is part of the solution rather than the problem faced by health systems in less developed countries.

Developing Countries↗
PubMed1996

Scientific data-exchange in periodontology via Internet.

The aim of the present paper was to study the current state of electronic scientific data-exchange in the field of dentistry and particularly in the specialty of periodontology. The use of electronic communication is unquestionably growing in all areas of life and has established itself in almost all areas of sciences and research. The potential use of Internet resources in the area of periodontology is the main topic of this paper. An overview explains the Internet system, its history, its structure, and the necessary hardware and software to use it. Text-orientated software and graphic interfaces like the World Wide Web will be described. Examples will be included to describing the basic services of Internet. The pros and cons of Internet use will be discussed and a preview of possible future developments in the field of communication for scientifically-oriented information will be included. This paper indicates that modern periodontal therapy and research may be enhanced by the use of Internet resources.

Communication↗