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At least 775 records · Page 43Linked to original sources
PubMed1998

A dynamic cadaver model of the stance phase of gait: performance characteristics and kinetic validation.

OBJECTIVE: This study was undertaken to evaluate the performance of a new dynamic laboratory model of the stance phase of gait. DESIGN: Five cadaver feet were repetitively tested in the apparatus. BACKGROUND: Typical biomechanical investigations of cadaver feet simply place a static load on the tibia. The present system was designed to better simulate the changing in-vivo loading environment of the foot and ankle during gait. METHODS: The device mimics the behavior of the tibia, foot, and ankle from heel-strike to toe-off by reproducing the physiologic actions of five extrinsic foot muscles and physiologic motion at the proximal tibia. To verify its utility, cadaver gait simulations were conducted while measuring applied muscle forces, ground reaction forces, and plantar pressures. RESULTS: Dynamic muscle forces were consistently delivered to within 10% of pre-programmed values. Dynamic measurements of ground reaction forces and plantar pressure were similar to those measured in healthy human subjects. Peak vertical (y), foreaft (x) and medio-lateral (z) forces were 110, 18, and 4% of body weight respectively. Compressive force in the tibial shaft reached 410% of body weight. RELEVANCE: Cadaver studies have greatly enhanced our understanding of normal and pathologic foot function, but are often limited by over-simplified loading conditions. The apparatus presented here accurately reproduces the in-vivo loading environment and provides a powerful investigational tool for the study of foot and ankle function. With this device, musculoskeletal structures can be examined in detail under biomechanical conditions similar to those they experience in life.

Journal Article↗
PubMed1999

Federal surveillance of veterinary drugs and chemical residues (with recent data).

The National Residue Program is a dynamic risk-based program involving many Federal agencies, with the objective of preventing illegal drug residues and chemicals in the food supply. Surveillance is the systematic collection, analysis, and interpretation of residue data for public health action. This consists of assessing the cause(s) of the problem, recommending educational incentives, and intervention of prevention and control measures. The role of residue databases in formulating policy decisions and identifying risk factors for drug residues is discussed. A descriptive analysis, of 5 years (1992-1996) field investigative reports of drug residue occurrence in food animals is presented. The results showed that violative residues occurred predominately in culled dairy cows and bob veal calves.

Animals↗
PubMedDate not supplied

Program evaluation. Part 1: Four generations of theory.

Program evaluation is necessary for understanding and improving educational programs in nursing, but it is frequently surrounded by a climate of unease and perplexity. This first article in a two-part series reviews and evaluates extant models of program evaluation using Guba and Lincoln's four generations of evaluation as a theoretical framework. The second article (November/December 1990) examines the state-of-the-art of program evaluation in nursing education and proposes implementation of a responsive model of program evaluation in schools of nursing. The series aims to foster more dynamic, efficient program analysis, thereby enhancing the effectiveness of nursing's educational programs.

Humans↗
PubMed1995

Observer-based dynamic patient modeling for diagnostic computer programs in long term treatment.

This article shows the dynamic patient model concept, the major argument of which is that the state of the patient could change during the computer aided diagnostic procedure. It introduces the definition of quasi parallel diagnostic systems and quasi parallel sensitive points. A kind of verification procedure can be seen for classical diagnostics, examining diagnostic systems by temporally behavior. The rest of the paper represents an adaptive diagnostic structure, convenient for observing and monitoring a dynamically modeled patient in long term treatment. The basis of the structure shown here is the observer theory presented and applied previously in signal processing.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

Changing men's attitudes and behavior: the Zimbabwe Male Motivation Project.

A multimedia communication campaign was conducted between 1988 and 1989 to promote family planning among men in Zimbabwe. The campaign consisted of a 52-episode semiweekly radio soap opera, about 60 motivational talks, and two pamphlets about contraceptive methods. Changes over time were measured by comparing a subset of a follow-up survey conducted from October to December 1989 to a baseline survey conducted from April to June 1988. Men exposed to the campaign were also compared to men who were not exposed. The follow-up survey revealed that the campaign reached 52 percent of men aged 18 to 55. Among married Shona-speaking men, use of modern contraceptive methods increased from about 56 percent to 59 percent during the campaign. Condom use increased from about 5 percent to 10 percent. Awareness and current use of modern contraceptives was also higher among men exposed to the campaign, primarily because of their greater awareness of condoms. Men exposed to the campaign were significantly more likely than other men to make the decision to use family planning and to say that both spouses should decide how many children to have.

Adolescent↗
PubMedDate not supplied

Contraceptive use and fertility decline in Chogoria, Kenya.

This article describes the results pertaining to fertility and family planning from a 1985 survey conducted in the catchment area of Chogoria Hospital in central Kenya. Current contraceptive prevalence was found to be quite high, 43 percent as opposed to 17 percent for Kenya as a whole. The total fertility rate of 5.2 births per woman was 2.5 births lower than the national rate. Very few women reported wanting to have large numbers of children or thinking that fate or God should determine family size. Although these data cannot conclusively demonstrate that the family planning program operating in the area has been responsible for reduced fertility there, they do provide some support for this hypothesis.

Adolescent↗
PubMed2001

Is sedation safe during dynamic sleep fluoroscopy of children with obstructive sleep apnea?

OBJECTIVE: Airway compromise is considered a relative contraindication for pediatric sedation. This contraindication presents a paradoxical problem when patients require sedation in preparation for imaging performed to evaluate the cause of airway obstruction. We use dynamic sleep fluoroscopy in the evaluation of children who have obstructive sleep apnea. The purpose of this study was to evaluate the success and safety of a structured sedation program for dynamic sleep fluoroscopy. MATERIALS AND METHODS: Eighty consecutive dynamic sleep fluoroscopic studies were evaluated. The type of sedation used, success rate, complications related to the sedation, and characteristics of the children studied were reviewed. Patients were sedated in accordance with our departmental sedation program guidelines. Findings on fluoroscopy were correlated with episodes of oxygen desaturation or noisy breathing. RESULTS: In all 80 cases, dynamic sleep fluoroscopy was successfully performed. Seventy-two studies were performed, with sedation supervised by the radiologist. Four patients fell asleep without sedation. In four patients, sedation was performed by an anesthesiologist (preprocedural decision). Sixty-four children (80%) had complex medical problems, and 39 (49%) had a history of previous airway surgery. All studies were considered successful. Specific diagnoses were identified in 66 children (83%). No children suffered complications or required tracheal intubation. CONCLUSION: Children with airway compromise who are being evaluated for obstructive sleep apnea can be successfully and safely sedated for dynamic sleep fluoroscopy when a structured sedation program is used.

Child, Preschool↗
PubMed1994

[Intensive back exercises 5 weeks after surgery of lumbar disk prolapse. A prospective, randomized multicenter trial with a historical control group].

An intensive, dynamic rehabilitation program applied to patients who had undergone first time lumbar discectomy was evaluated in a multicentre, clinical trial. Ninety-six patients between 18 and 70 years of age who had been operated within the period September 1989 to May 1990 at the Department of Neurosurgery, Copenhagen County Hospital, Glostrup were consecutively randomized into one of two rehabilitation programs: a) traditional mild, general mobility-improving exercises within pain limits; or b) intensive dynamic back extension and abdominal exercises without low back pain being the limiting factor. Both groups underwent 14 hours of treatment over a period of six weeks, starting five weeks after surgery. Seventy-six patients operated within the period January 1989 to September 1989 formed the historical control group. The results at follow-up at 26 weeks favoured intensive exercises with regard to the patients disability-index and working capabilities. The results are statistically significant. After one year a trend favouring intensive exercises can be observed. No differences in pain or objective measurements were found. A rehabilitation program using intensive exercises without back pain being the limiting factor appears to give the patients increased behavioural support, resulting in improvements in work capacity and reduction in patients' self-rated disability.

Adolescent↗
PubMed2006

Effects of two 4-week proprioceptive neuromuscular facilitation programs on muscle endurance, flexibility, and functional performance in women with chronic low back pain.

BACKGROUND AND PURPOSE: Improving functional performance in patients with chronic low back pain is of primary importance. The purpose of this study was to examine the effects of 2 proprioceptive neuromuscular facilitation (PNF) programs on trunk muscle endurance, flexibility, and functional performance in subjects with chronic low back pain (CLBP). SUBJECTS: Eighty-six women (40.2+/-11.9 [mean+/-SD] years of age) who had complaints of CLBP were randomly assigned to 3 groups: rhythmic stabilization training, combination of isotonic exercises, and control. METHODS: Subjects trained with each program for 4 weeks with the aim of improving trunk stability and strength. Static and dynamic trunk muscle endurance and lumbar mobility were measured before, at the end of, and 4 and 8 weeks after training. Disability and back pain intensity also were measured with the Oswestry Index. RESULTS: Multivariate analysis of variance indicated that both training groups demonstrated significant improvements in lumbar mobility (8.6%-24.1%), static and dynamic muscle endurance (23.6%-81%), and Oswestry Index (29.3%-31.8%) measurements. DISCUSSION AND CONCLUSION: Static and dynamic PNF programs may be appropriate for improving short-term trunk muscle endurance and trunk mobility in people with CLBP.

Adult↗
PubMed2001

Linking population-level risk assessment with landscape and habitat models.

Ecological risk assessment at the population level often involves predicting the effects of a particular change in the land-use patterns on the viability of native species. A common method of addressing such questions is modeling the metapopulation dynamics of the species in the landscape. However, the landscape and, as a result, the spatial structure of the metapopulation usually do not remain unchanged, thus the assessment of viability must incorporate the dynamic nature of the landscape. A new link being developed between a metapopulation modeling program (RAMAS) and a landscape dynamics program (LANDIS) will allow the transitional dynamics of the landscape to be incorporated into assessment of viability and threat. This approach combines methods of landscape prediction with those of metapopulation simulation. The link between the landscape model and metapopulation model is provided by statistical models of habitat suitability for the species in focus.

Animals↗
PubMed1982

The demographic impact of the family planning--health services project in Matlab, Bangladesh.

This paper evaluates the demographic impact of the Family Planning-Health Services Project in Matlab Thana of rural Bangladesh. The project was begun by the International Centre for Diarrhoeal Disease Research, Bangladesh in October 1977. Contraceptive services--including pills, condoms, IUDs, sterilization, and injectables--are supplemented by oral rehydration, tetanus toxoid, and other services. About 33 percent of eligible couples are using contraception. Impact is evaluated by direct measurement of birth rates in the treatment and comparison areas. An overall fertility decline of about 25 percent is observed, concentrated among older women. The impact is two-to-three times that of an earlier project that included fewer methods and used lesser trained workers. The study shows that intensive family planning efforts can affect fertility in the absence of socioeconomic changes.

Adolescent↗
PubMedDate not supplied

Reweighting DHS data to serve multiple perspectives.

Information about health and family planning infrastructures is collected through the service availability module (SAM), an important feature of the Demographic and Health Surveys (DHS) conducted in many developing countries. The DHS samples were designed to provide a representative sample of households and women of reproductive age. Using the weights routinely provided with DHS data sets, service accessibility can be described straightforwardly at the individual and household levels. However, without further adjustment, SAM data do not provide a representative picture of service delivery at the community, or primary sampling unit, level, where the data are collected. This report proposes a methodology for reweighting the SAM data, using rural data from the Egypt DHS as an illustration, so that available family planning facilities at this level may be usefully characterized at little additional cost.

Adolescent↗
PubMed2004

Distributed interactive virtual environments for collaborative experiential learning and training independent of distance over Internet2.

Medical knowledge and skills essential for tomorrow's healthcare professionals continue to change faster than ever before creating new demands in medical education. Project TOUCH (Telehealth Outreach for Unified Community Health) has been developing methods to enhance learning by coupling innovations in medical education with advanced technology in high performance computing and next generation Internet2 embedded in virtual reality environments (VRE), artificial intelligence and experiential active learning. Simulations have been used in education and training to allow learners to make mistakes safely in lieu of real-life situations, learn from those mistakes and ultimately improve performance by subsequent avoidance of those mistakes. Distributed virtual interactive environments are used over distance to enable learning and participation in dynamic, problem-based, clinical, artificial intelligence rules-based, virtual simulations. The virtual reality patient is programmed to dynamically change over time and respond to the manipulations by the learner. Participants are fully immersed within the VRE platform using a head-mounted display and tracker system. Navigation, locomotion and handling of objects are accomplished using a joy-wand. Distribution is managed via the Internet2 Access Grid using point-to-point or multi-casting connectivity through which the participants can interact. Medical students in Hawaii and New Mexico (NM) participated collaboratively in problem solving and managing of a simulated patient with a closed head injury in VRE; dividing tasks, handing off objects, and functioning as a team. Students stated that opportunities to make mistakes and repeat actions in the VRE were extremely helpful in learning specific principles. VRE created higher performance expectations and some anxiety among VRE users. VRE orientation was adequate but students needed time to adapt and practice in order to improve efficiency. This was also demonstrated successfully between Western Australia and UNM. We successfully demonstrated the ability to fully immerse participants in a distributed virtual environment independent of distance for collaborative team interaction in medical simulation designed for education and training. The ability to make mistakes in a safe environment is well received by students and has a positive impact on their understanding, as well as memory of the principles involved in correcting those mistakes. Bringing people together as virtual teams for interactive experiential learning and collaborative training, independent of distance, provides a platform for distributed "just-in-time" training, performance assessment and credentialing. Further validation is necessary to determine the potential value of the distributed VRE in knowledge transfer, improved future performance and should entail training participants to competence in using these tools.

Computer Simulation↗
PubMed2003

Experimental evaluation of an elastic foundation model to predict contact pressures in knee replacements.

Computational wear prediction is an attractive concept for evaluating new total knee replacement designs prior to physical testing and implementation. An important hurdle to such technology is the lack of in vivo contact pressure predictions. To address this issue, this study evaluates a computationally efficient simulation approach that combines the advantages of rigid and deformable body modeling. The hybrid method uses rigid body dynamics to predict body positions and orientations and elastic foundation theory to predict contact pressures between general three-dimensional surfaces. To evaluate the method, we performed static pressure experiments with a commercial knee implant in neutral alignment using flexion angles of 0, 30, 60, and 90 degrees and loads of 750, 1500, 2250, and 3000N. Using manufacturer CAD geometry for the same implant, an elastic foundation model with linear or nonlinear polyethylene material properties was implemented within a commercial multibody dynamics software program. The model's ability to predict experimental peak and average contact pressures simultaneously was evaluated by performing dynamic simulations to find the static configuration. Both the linear and nonlinear material models predicted the average contact pressure data well, while only the linear material model could simultaneously predict the trends in the peak contact pressure data. This novel modeling approach is sufficiently fast and accurate to be used in design sensitivity and optimization studies of knee implant mechanics and ultimately wear.

Compressive Strength↗