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PubMedDate not supplied

The freeware AIDA interactive educational diabetes simulator--http://www.2aida.org--(2). Simulating glycosylated haemoglobin (HbA1c) levels in AIDA v4.3.

In 1996 an interactive educational diabetes simulator called AIDA was released without charge on the Internet as a non-commercial contribution to continuing diabetes education. Over the past 4+ years over 74,000 people have visited the AIDA Web pages at http://www.2aida.org and over 20,000 copies of the program have been downloaded from there free-of-charge. This article builds on the experience gained from the AIDA development, and the World Wide Web distribution of the software, and highlights some of the problems which users have reported with the program. An updated release of the software (AIDA v4.3) is described and the method applied for modelling glycosylated haemoglobin (HbA1c) levels within this new version of AIDA is documented. An overview is provided of the trialling and beta-testing of this latest release of the program, and the general concept of a 'virtual diabetic patient' that provides an electronic representation of a patient with diabetes--and which can be used for self-learning/teaching/demonstration purposes--is highlighted.

Computer Simulation↗
PubMed1992

[Computer simulation of blood level profiles. Drug liberation from two sustained-release preparations and computer simulation of single- and multiple-dose pharmacokinetics].

A series of computer programs (BASIC) is introduced for the evaluation of in vitro dissolution data as well as for the calculation of pharmacokinetic parameters and for blood level curve fitting to the respective in vitro data. Furthermore, programs are offered for the simulation of blood level profiles under variable conditions. In order to demonstrate the practical use of these programs, the expected blood level profiles following the administration of two commercial sustained-release dosage forms containing the drug pentoxifylline have been compared.

Computer Simulation↗
PubMed2006

The Surgical Simulation and Training Markup Language (SSTML): an XML-based language for medical simulation.

Under contract with the Telemedicine & Advanced Technology Research Center (TATRC), Energid Technologies is developing a new XML-based language for describing surgical training exercises, the Surgical Simulation and Training Markup Language (SSTML). SSTML must represent everything from organ models (including tissue properties) to surgical procedures. SSTML is an open language (i.e., freely downloadable) that defines surgical training data through an XML schema. This article focuses on the data representation of the surgical procedures and organ modeling, as they highlight the need for a standard language and illustrate the features of SSTML. Integration of SSTML with software is also discussed.

Computer Simulation↗
PubMed1989

[Effects of longterm selection on the genetic structure of populations--a simulation study. I. Simulation models and selection responses].

Monte Carlo method has been utilized to investigate responses to longterm selection. The simulation involves 3 gene effect models (additive, dominant, and over-dominant), two population sizes, three linkage intensities, and three heritability levels, thus making 54 combinations. For each combination, 5 replicate populations are selected over 49 consecutive non-overlapping generations. The results demonstrate that under all the gene effect models, linkage is important only in the case of small populations and intense linkage, when it reduces responses significantly due to hampering the fixation of favourable alleles and accelerating their loss. Linkage has no apparent effect if it is not very tight or if the population is large. Much greater responses are achieved in the large populations than in the small ones, especially for traits with low heritability. Among those discussed are problems of crossing selected lines to obtain extra responses, and discrepancy of some theoretic results on selection limits.

Computer Simulation↗
PubMed1987

[Simulation, dissimulation, and simulation games in teaching and in surgical diagnosis].

The characteristic aspects of the year's course in Surgical Symptomatology included in the curriculum of the degree course in Medicine and Surgery are examined. The report covers the student's behaviour at the first contact with the patient, his initial reaction and subsequent professional acclimatization, the techniques of didactic simulation and the new diagnostic technologies that essentially follow the dialectic of the "electronic game". Direct personal evidence and selected technical documentation constitute the demonstrative back up for the various points under discussion.

Computer Simulation↗
PubMed1978

Dissolution kinetics of cholesterol in simulated bile II: influence of simulated bile composition.

Normal human gallbladder bile and gallbladder bile of patients undergoing chenodeoxycholic acid therapy were simulated by using appropriate combinations of taurine and glycine conjugates of cholic, chenodeoxycholic, and deoxycholic acids. Also, the total bile acid concentration and the total bile acid to lecithin ratio were varied over physiological ranges. Dissolution rates of cholesterol monohydrate pellets (model gallstone) in these solutions were 90--99% interfacially controlled. Even under conditions favorable for dissolution, i.e., high bile acid concentration and high bile acid to lecithin ratio, the interfacial resistances were extremely large. These results are of the same order of magnitude as those found in the limited studies with actual gallbladder bile and suggest that the bile acids, lecithin, and the electrolytes are the primary determinants of the interfacial resistance for cholesterol dissolution. Furthermore, the kinetics of dissolution were always much faster with the chenodeoxycholic acid-rich compositions than with the corresponding normal compositions. This finding suggests, therefore, that in addition to desaturating bile with respect to cholesterol, the feeding of chenodeoxycholic acid further facilitates cholesterol gallstone dissolution by reducing the interfacial resistance of the process.

Bile↗
PubMed1997

Effect of the addition of Peptostreptococcus productus ATCC35244 on the gastro-intestinal microbiota and its activity, as simulated in an in vitro simulator of the human gastro-intestinal tract.

Peptostreptococcus productus ATCC35244, a reductive acetogenic strain, was added daily over 9 successive days to the fourth vessel (ascending colon) of the SHIME, a six-stage reactor system simulating the in vivo continuous culture conditions of the human gastro-intestinal tract. Final numbers of organisms (cfu)/ml reactor contents (c) were attained such that log10c = 6.9 +/- 0.1. The addition caused the CH4 production to decrease below the detection limit while total gas and CO2 production in the fifth (transverse colon) and sixth reactor (descending colon) were lowered and the acetic acid concentration was augmented. Ending the supplementation caused CH4 production to re-establish within 4 days, while CO2 production increased much more slowly. The concentration of acetic acid only started to decrease after 7 days. The results indicate that P. productus, upon regular administration, is able to compete with methanogens for H2 in the gastro-intestinal microbial ecosystem because of its reductive acetogenic character.

Acetic Acid↗
PubMed2004

Disruptive visions: predictive simulation--between scientific method and clinical trial is the role of modeling and simulation in scientific discovery and validation.

The foundations of surgery have rested upon the passing of knowledge from generation to generation by mentors and manuscripts. Until the 1900 s, the passage of knowledge was through tradition. Since then, it has changed from observation and experience to the scientific method to clinical trials. A new approach, derived from other scientific disciplines, is that of predicting results from modeling and simulation, which will allow for acceleration of the process of validation of discoveries and optimizing the implementation of clinical trials in order to more rapidly transfer trusted knowledge from generation to generation.

Biomedical Research↗
PubMed2005

A comparison of experimental and simulated propagators in porous media using confocal laser scanning microscopy, lattice Boltzmann hydrodynamic simulations and nuclear magnetic resonance.

Confocal laser scanning microscopy has been used to obtain 3D optical image stacks of packings of glass ballotini in various fluorescent dye-containing fluids inside a 3D micromodel. The fluids' refractive index was matched to that of the glass ballotini so that clear images at an appreciable depth (approximately 400 microm) inside the packings were obtained. The lattice Boltzmann method was then used to produce 3D velocity fields through the 3D image stacks of the packed ballotini. These have been used in conjunction with a stochastic random-walk algorithm to produce simulated displacement propagators, which have been shown to be in qualitative agreement with experimental propagators, obtained using nuclear magnetic resonance, of water flowing through the exact same micromodel.

Algorithms↗
PubMed2004

Raptor: combining dual-shell representation, induced-fit simulation, and hydrophobicity scoring in receptor modeling: application toward the simulation of structurally diverse ligand sets.

We present a novel receptor-modeling approach (software Raptor) based on multidimensional quantitative structure-activity relationships (QSARs). To accurately predict relative free energies of ligand binding, it is of utmost importance to simulate induced fit. In Raptor, we explicitly and anisotropically allow for this phenomenon by a dual-shell representation of the receptor surrogate. In our concept, induced fit is not limited to steric aspects but includes the variation of the physicochemical fields along with it. The underlying scoring function for evaluating ligand-receptor interactions includes directional terms for hydrogen bonding and hydrophobicity and thereby treats solvation effects implicitly. This makes the approach independent from a partial-charge model and, as a consequence, allows one to smoothly model ligand molecules binding to the receptor with different net charges. We have applied the new concept toward the estimation of ligand-binding energies associated with the chemokine receptor-3 (50 ligands: r(2) = 0.965; p(2) = 0.932), the bradykinin B(2) receptor (52 ligands: r(2) = 0.949; p(2) = 0.859), and the estrogen receptor (116 ligands: r(2) = 0.908; p(2) = 0.907), respectively.

Binding Sites↗
PubMed1988

Phenobarbital adsorption from simulated intestinal fluid, U.S.P., and simulated gastric fluid, U.S.P., by two activated charcoals.

Adsorption of phenobarbital from simulated intestinal and gastric fluids by two activated charcoals was studied. Adsorption isotherm data were analyzed by the linearized Langmuir equation and by nonlinear least-squares regression employing both Langmuir and Freundlich models. These analyses indicated differences in the capacities of the two charcoals for phenobarbital which could not be completely explained by surface-area considerations.

Adsorption↗
PubMed2003

In vitro simulation of stance phase gait part II: Simulated anterior tibial tendon dysfunction and potential compensation.

The diagnosis of anterior tibial tendon tear is often missed. The ability of the remaining ankle extensor muscles to compensate for lost anterior tibial force was thus investigated. The effect of tibialis anterior deficiency on tarsal bone motion and plantar pressure was measured during in vitro simulated stance phase gait on eight cadaver specimens. Increased internal rotation, plantarflexion, and inversion of the talus and calcaneus (p < or = .001), as well as significant reductions of plantar pressure on the heel (p < or = .04) were observed during the first half of the stance phase. The observed drop foot was partly compensated by increased extensor muscle force.

Aged↗
PubMed2003

Using Advanced Continuous Simulation Language (ACSL) to simulate, solve, and fit mathematical models in nutrition.

The ACSL programs (AEgis Technologies, 2000a, b) are fairly easy to use and provide a good combination of canned programming with the flexibility to do more, if one is willing to learn the language (for Fortran and m files). The manuals are fairly easy to understand but are not detailed enough. The manuals are geared toward operating the software. For the Optimize software, the best references are the Simusolv manuals (Steiner et al., 1990). ACSL also provides an interface (Open API or ACSL Server) which can be purchased separately. The interface allows compiled models to be distributed and run as independent programs with Visual Basic or C/C++. For models built with the Graphic Modeler, the interface is shareware.

Animals↗