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PubMed1994

[A computer program to calculate expected cases in a dynamic cohort].

ECIDC (Expected Cases in Dynamic Cohorts) is a new interactive computerized programme in English for personal computers, created specifically to calculate expected cases in prospective cohort studies. Programmes available up to now have calculated the denominators of measurements of frequency, expressed in person-years, using the recruitment date and exit date of each individual in the cohort. ECIDC, instead, calculates directly the number of expected cases, recognizing only the date of recruitment. The programme considers the aging of the cohort, estimates the effect due to competitive mortality and eliminates the expected deaths. Then, it calculates the expected cases by applying incidence or specific mortality from the reference population. ECIDC considers the period effects of both competitive mortality and expected incidence. When observed reference data is lacking, it compiles estimates of age-specific incidence and/or mortality trends. ECIDC can be used in power calculation for the cohort study. It also can be applied to simulation studies of incidence and mortality trends. The present paper tries out various simulations and shows the potential of the computerized programme.

Adolescent↗
PubMed1996

TRICARE: implications for military executive management education--a review of current data.

The Military Health Services System (MHSS) is undergoing major modifications brought about by the Department of Defense health care reform program (TRICARE), a dynamic, multi-dimensional reform initiative affecting health care delivery to eligible beneficiaries. Military managers of the MHSS are currently being impacted by the changes secondary to the implementation of TRICARE. By reviewing needs assessments conducted with these managers, surveying currently available programs and curricula aimed at military health care manager development, and examining the TRICARE concept, it is clear that executive education must be adapted to fit the needs of those who will manage this newly designed and rapidly evolving health care system. This report summarizes current military executive education options and specifically examines the Naval Postgraduate School Executive (Medical) Management Education (EME) Program. This EME Program can support military medical treatment facility and lead agents (Health Service Regions) executive managers in the execution of their TRICARE mission.

Administrative Personnel↗
PubMed2002

Verification of dynamic and segmental IMRT delivery by dynamic log file analysis.

A program has been developed to evaluate the delivered fluence of step-and-shoot segmental and sliding window dynamic multileaf collimator (MLC) fields. To automate these checks, a number of tools have been developed using data available from the dynamic log files that can be created each time a dynamic delivery occurs. Experiments were performed with a Varian 2100EX with a 120 leaf MLC equipped with dynamic capabilities. A dynamic leaf sequence is delivered and measured with film or an amorphous silicon imager. After delivery, the dynamic log file is written by the accelerator control system. The file reports the expected and actual position for each leaf and the dose fraction every 0.055 seconds. Leaf trajectories are calculated from this data and expected and actual fluence images are created from the difference of opposing leaf trajectories. These images can be compared with the expected delivery, measurements, and calculations of fluence. Tools have been developed to investigate other aspects of the delivery, such as specific leaf errors, beam hold-off flags sent by the control system to the MLC, and gap widths. This program is part of a semi-automated quality assurance (QA) system for pretreatment fluence verification and daily treatment verification of dynamic multileaf collimation (DMLC) delivery.

Computer Simulation↗
PubMed1987

A computerized system for modeling pacemaker rhythms.

We have developed a computer program which simulates a paced cardiac rhythm strip, graphically generating the electrocardiogram (ECG) on a color monitor. Any pacemaker, programmed as desired, dynamically interacts with a preselected intrinsic rhythm. Utilizing symbols prevalent in the pacing industry, this graphics-oriented, interactive system promotes a rapid understanding of pacemaker function by automatically superimposing specific pacemaker events on a rhythm strip. These events include: pacemaker spikes, evoked cardiac depolarization waveforms, refractory periods, upper rate intervals, and blanking periods. Applications of this program include interpreting and verifying appropriate pacemaker function, demonstrating idiosyncrasies of the various pacemakers, and teaching.

Computer Graphics↗
PubMed1997

Home exercise and compliance in inflammatory rheumatic diseases--a prospective clinical trial.

OBJECTIVE: To survey and to compare the one year effects of dynamic muscle training and progressive muscle relaxation as home exercise for patients with inflammatory rheumatic diseases; and to identify predictors for compliance with a longterm home exercise regimen. METHODS: Fifty-four patients (mean age 54 yrs, mean symptom duration 14 yrs) were assessed for health related quality of life, exercise motivation, joint tenderness, and physical capacities. After randomization into 2 groups, every patient was instructed on one occasion in a 30 min program of either dynamic training or muscle relaxation to carry out at home, 5 times a week during 3 months, and then 2-3 times a week for another 9 months. RESULTS: Seventeen patients in each group completed the one year exercise protocol, while 10 from each group did not. Compliance with the one year exercise regimen seemed to be predicted by high self-efficacy for exercise, regular range-of-motion exercises before the intervention, and being unmarried. After one year, minor improvements in physical effect (p < or = 0.05) and work effect (p < or = 0.05) were found in the dynamic training group, while minor improvements in pain effect (p < or = 0.05), emotional reactions (p < or = 0.05), and arm endurance (p < or = 0.01) were found in the muscle relaxation group. No differences between the groups regarding changes in health status, joint tenderness, or physical capacities during the intervention period were found. CONCLUSION: These results may improve the selection of patients for home exercise, and form a basis for improved administration of home exercise programs.

Adult↗
PubMed1992

Severe contractures of the proximal interphalangeal joint in Dupuytren's disease: results of a prospective trial of operative correction and dynamic extension splinting.

In a prospective study, 23 proximal interphalangeal joints that were severely contracted (> or = 45 degrees) as a result of Dupuytren's disease underwent operative correction and 6 months of dynamic extension splinting. Proximal interphalangeal joint extension was measured preoperatively and postoperatively at 3-month intervals for 1 year and at 6-month intervals thereafter. Mean follow-up was 2 years (minimum, 1 year). Overall, at 2 years, 44% improvement in proximal interphalangeal joint extension was noted. Mean improvement of 59% in proximal interphalangeal joint extension was noted in patients who complied with the postoperative dynamic extension splinting program. Patients who were noncomplaint demonstrated a 25% improvement in proximal interphalangeal joint extension. The difference in values between patients who were compliant and those who were not was statistically significant. Other factors--severity of contracture, digit involved, and the necessity for capsular release--were not significantly related to outcome. This study suggests that soft tissue responds to continuous dynamic extension stresses and can be remodeled over time.

Adult↗
PubMed1998

Modified cyclodextrins as chiral selectors: molecular modelling investigations on the enantioselective binding properties of heptakis(2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl)-beta-cyclodextri n.

Molecular modelling methods have been used to investigate the enantioselective binding properties of chiral dihydrofuranones on heptakis(2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl)-beta-cyclod extrin in capillary gas chromatography. A conformational analysis of the modified beta-cyclodextrin was performed using annealed molecular dynamics. With the program GRID the molecular interaction potential for each of the received energetically reasonable structures of the beta-cyclodextrin and the dihydrofuranones was evaluated using different probe groups. The results of these computations have been used as starting points for constructing geometrically reasonable host-guest complexes between the beta-cyclodextrin and the dihydrofuranones. The subsequently performed molecular dynamics simulations yielded different complex states reflecting the conformational flexibility of the diastereomeric complexes. Considering the evaluated interaction energy between the beta-cyclodextrin and the dihydrofuranones as a measure of complex stability the results are in close agreement with the experimentally determined elution sequences. The methodology for the construction of the interaction model used in this study is capable of simulating the experimental data. We believe that it may serve as a basis for predictions of hitherto unknown elution sequences at modified cyclodextrins.

Carbohydrate Sequence↗
PubMed1993

Strength training alters contractile properties of the triceps brachii in men aged 65-78 years.

Voluntary and electrically evoked contractile properties were studied in the triceps brachii following a 24-week dynamic strength training program in ten men aged 65-78 years. Eight men of a similar age were control subjects. A resistance overload program was undertaken three times per week with subjects performing four sets of six to eight repetitions at 80% of their one repetition on maximum (1RM). Maximum voluntary contraction (MVC) and contractile properties were measured at 0, 12, and 24 weeks in the exercise group and at 0 and 24 weeks in the controls. The 1RM was used to assess dynamic strength at 0 and 24 weeks in the exercise group. Contractile measures consisted of supramaximal isometric twitch and post-activation twitch parameters. Muscle size was estimated from anthropometric measurements. Compared with the control group, the exercise group MVC increased by about 20% and time to peak tension was slowed by about 11%. Also in the exercise group the peak rate of torque development of the potentiated twitch was reduced by about 10%. Twitch potentiation was substantial in both groups (about 140%) and unaffected by training. The 1 RM increased by about 30%, and there was a non-significant positive change of 8.6% in the muscle plus bone cross-sectional area in the exercise group. The results show that the force generating capacity of the triceps brachii in these men can be significantly improved for up to 24 weeks using concentric overload training. Furthermore, the finding of slowed twitch properties and no change in peak twitch amplitude substantiate and extend the limited data currently available on intrinsic contractile changes in the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2005

Time-resolved particle image velocimetry and laser doppler anemometry study of the turbulent flow field of bileaflet mechanical mitral prostheses.

Dynamic particle image velocimetry (PIV) was applied to the study of the flow field associated with prosthetic heart valves. The results were compared with those of laser Doppler anemometry (LDA). Anatomically and antianatomically oriented Jyros (JR) and St. Jude Medical (SJM) valves were compared in the mitral position to study the effects of valve design on the downstream flow field. The experimental program used a dynamic PIV system utilizing high-speed, high-resolution video to map the true time-resolved velocity field inside the simulated ventricle. This system was complemented by a study using the more traditional LDA system for comparison. Based on the experimental data, the following general conclusions can be made. High-resolution dynamic PIV can capture true chronological changes in the velocity and turbulence fields. It also produces very detailed velocity and turbulence information comparable to the LDA results. In the vertical measuring plane that passes both the center of the aortic and mitral valves (A-A section), the two valves (the SJM and the JR) show distinct circulatory flow patterns when the valve is installed in the antianatomical orientation. Small differences in valve design can generate noticeable differences, particularly during the accelerating flow phase. The SJM valve maintains a relatively high velocity through the central orifice; the curved leaflets of the JR valve generate higher velocities with a divergent flow during the accelerating and peak flow phases. In the velocity field directly below the mitral valve and normal to the previous measuring plane (B-B section), where characteristic differences in valve design will be visible, symmetrical twin circulations were observed because of the divergent nature of the flow generated by the two inclined half-disks installed in the antianatomical orientation. The SJM valve, with a central downward flow near the valve, is contrasted with the JR valve, which has a peripheral downward circulation with higher, turbulent stresses.

Heart Valve Prosthesis↗
PubMed2003

Children's feeding programs in Atlantic Canada: some Foucauldian theoretical concepts in action.

Since 1989 the number of Canadian children depending on food banks has increased by more than 85%. To combat perceived hunger, breakfast and lunch programs have been initiated by localized volunteer efforts. This paper attempts to show the Foucauldian concepts of power, truths, space and time in action in feeding programs in Atlantic Canada. A potential 'relation of docility-utility' is imposed upon children by providers of feeding programs and ultimately the state. The 'power over life' or 'micro-physics of power' is accomplished through procedures that use food, rules, rewards, reinforcements, space, time, and truths. Children voluntarily subject themselves to this relation while reserving the power to resist through acts of defiance or by not attending at all. This ability to exercise one's agency allows for shifting power relations in the social dynamics of feeding programs. The potentially coercive nature of these relationships is embedded in the pleasurable environment generated by the feeding process.

Canada↗
PubMed2001

Dynamic water exercise in individuals with late poliomyelitis.

OBJECTIVE: To evaluate the specific effects of general dynamic water exercise in individuals with late effects of poliomyelitis. DESIGN: Before-after tests. SETTING: A university hospital department. PARTICIPANTS: Twenty-eight individuals with late effects of polio, 15 assigned to the training group (TG) and 13 to the control group (CG). INTERVENTION: The TG completed a 40-minute general fitness training session in warm water twice weekly. Assessment instruments included the bicycle ergometer test, isokinetic muscle strength, a 30-meter walk indoors, Berg balance scale, a pain drawing, a visual analog scale, the Physical Activity Scale for the Elderly, and the Nottingham Health Profile (NHP). MAIN OUTCOME MEASURES: Peak load, peak work load, peak oxygen uptake, peak heart rate (HR), muscle function in knee extensors and flexors, and pain dimension of the NHP. RESULTS: The average training period was 5 months; compliance was 75% (range, 55-98). No negative effects were seen. The exercise did not influence the peak work load, peak oxygen uptake, or muscle function in knee extensors compared with the controls. However, a decreased HR at the same individual work load was seen, as well as a significantly lower distress in the dimension pain of the NHP. Qualitative aspects such as increased well-being, pain relief, and increased physical fitness were reported. CONCLUSIONS: A program of nonswimming dynamic exercises in heated water has a positive impact on individuals with late effects of polio, with a decreased HR at exercise, less pain, and a subjective positive experience. The program was well tolerated (no adverse effects were reported) and can be recommended for this group of individuals.

Adult↗
PubMed1999

[Methods of rehabilitation of fingers after the repair of flexor tendon injuries of first and second degree].

Post-operative rehabilitation of fingers after flexor tendon repair is the important part of therapy which considerably affects final result of the treatment. Method of dynamic traction splinting introduced by Kleinert in 1973, resulted in significantly improvement of final outcomes of repaired flexor tendons, particularly in zone II. Several other than Kleinert dynamic splinting rehabilitation programs were described in the paper. These methods are precisely designed protocols including mode and duration of immobilization of the fingers in the cast, daily range and frequency of finger moves and rate of restoration of the full range of motion. The following rehabilitation protocols were described: active flexion-active extension (Billericay and Belfast), active flexion-active extension using an internal profundus splinting, passive flexion-passive extension and combined regimen of controlled motion with dynamic traction splinting. The late results of the treatment using mentioned above rehabilitation protocols were compared, with respect to proportion of excellent and good results and rate of ruptures of repaired tendons in the course of rehabilitation. Combined regimen of controlled motion with dynamic traction splinting appeared to be superior than other presented methods. There was mentioned that Kleinert dynamic traction splinting, which is the most frequently used post-operative protocol after flexor tendon repairs in Poland, is not the only way of rehabilitation and that other presented methods give comparable results and may be used as an effective, alternative technique.

Clinical Protocols↗
PubMedDate not supplied

Microcomputer simulation as an aid in analyzing data and teaching the principles of glomerular dynamics.

This report describes a simple program, written in BASIC language, that closely emulates a previously published network thermodynamic model of glomerular dynamics. While the latter requires the SPICE 2 simulation program and a mainframe computer for its execution, the present program operates on any IBM-compatible microcomputer. It has equal utility as an aid in the interpretation of laboratory studies of glomerular dynamics and as a tool for teaching the intricacies of the control of glomerular function. The program is available in 'user friendly' format that obviates the need for any expertise in the use of computers.

Computer Simulation↗
PubMed1999

Balance training for persons with functionally unstable ankles.

STUDY DESIGN: A nonrandomized 2-group pretest-posttest design. OBJECTIVES: To determine the effects of a 4-week balance training program during stance on a single leg. BACKGROUND: Individuals who have experienced multiple episodes of inversion ankle sprains often participate in balance training programs. Balance training is performed to treat existing proprioceptive deficits and to restore ankle joint stability, presumably by retraining altered afferent neuromuscular pathways. The effectiveness of such programs on individuals with functionally unstable ankles has yet to be established. METHODS AND MEASURES: Prior to and following training, subjects with self-reported functionally unstable ankles (5 women and 8 men, mean age = 21.9 +/- 3.1 years) and nonimpaired subjects (6 women and 7 men, mean age = 21.2 +/- 2.5 years) completed a static balance assessment for both limbs as well as the ankle joint functional assessment tool questionnaire (AJFAT). The subjects from both groups participated in a unilateral, multilevel, static and dynamic balance training program 3 times a week for 4 weeks. Subjects from the experimental group trained only the involved limb, and the nonimpaired group trained a randomly selected limb. A stability index (SI) was calculated during the balance assessment to indicate the amount of platform motion. Compared to low stability indices, high stability indices indicate greater platform motion during stance and therefore less stability. RESULTS: Following training, subjects from both groups demonstrated significant improvements in balance ability. When balance was assessed at a low resistance to platform tilt (stability level 2), the posttraining scores of both the subjects with unstable ankles (mean SI = 2.63 +/- 1.92) and the nonimpaired subjects (mean SI = 2.69 +/- 2.32) were significantly better than their pretraining scores (mean SIs = 5.93 +/- 3.65 and 4.67 +/- 3.43, respectively). Assessed at a high resistance to platform tilt (stability level 6), the posttraining scores of both subjects with unstable ankles (mean SI = 1.27 +/- 0.66) and the nonimpaired subjects (mean SI = 1.37 +/- 0.66) were significantly better than their pretraining scores (mean SIs = 2.30 +/- 1.88 and 2.04 +/- 1.43, respectively). Additionally, the posttraining AJFAT scores of subjects with unstable ankles (25.78 +/- 3.80) and the nonimpaired subjects (29.15 +/- 5.27) were significantly greater than their pretraining scores (17.11 +/- 3.44 and 22.92 +/- 5.22, respectively), indicating an overall improvement in perceived ankle joint functional stability. CONCLUSIONS: This study suggests that balance training is an effective means of improving joint proprioception and single-leg standing ability in subjects with unstable and nonimpaired ankles.

Adolescent↗
PubMed1993

Living with mental illness: professional/family collaboration.

What started as a pilot project in the spring of 1990 has matured into a successful ongoing enterprise between professionals and families that continues to meet the needs of families experiencing the impact of mental illness. According to self-administered evaluations completed by those in attendance, and a subjective review by the planning committee, the program was an immediate success. It attained its overall education and mutual support objectives, and fostered successful collaboration between professionals and families. One hundred percent of family participants indicated that they would recommend the workshop to others in similar situations. In managing mental illness through collaborative partnerships, the family must be an integral part of each phase of project development. Family members are the "thermometer," measuring how closely the project is mirroring their needs. Since its inception, 370 people have participated in this dynamic project. This program demonstrates that through understanding, respect, and positive regard, families, friends, and professionals can work collaboratively to enhance the quality of life for all who are victimized by mental illness.

Adaptation, Psychological↗
PubMed2004

Apoptotic cell death dynamics of HL60 cells studied using a microfluidic cell trap device.

This paper presents the design, fabrication and first results of a microfluidic cell trap device for analysis of apoptosis. The microfluidic silicon-glass chip enables the immobilization of cells and real-time monitoring of the apoptotic process. Induction of apoptosis, either electric field mediated or chemically induced with tumour necrosis factor (TNF-alpha), in combination with cycloheximide (CHX), was addressed. Exposure of cells to the appropriate fluorescent dyes, FLICA and PI, allows one to discriminate between viable, apoptotic and necrotic cells. The results showed that the onset of apoptosis and the transitions during the course of the cell death cascade were followed in chemically induced apoptotic HL60 cells. For the case of electric field mediated cell death, the distinction between apoptotic and necrotic stage was not clear. This paper presents the first results to analyse programmed cell death dynamics using this apoptosis chip and a first step towards an integrated apoptosis chip for high-throughput drug screening on a single cellular level.

Apoptosis↗
PubMed1999

Evolution and development of a central pattern generator for the swimming of a lamprey.

This article describes the design of neural control architectures for locomotion using an evolutionary approach. Inspired by the central pattern generators found in animals, we develop neural controllers that can produce the patterns of oscillations necessary for the swimming of a simulated lamprey. This work is inspired by Ekeberg's neuronal and mechanical model of a lamprey [11] and follows experiments in which swimming controllers were evolved using a simple encoding scheme [25, 26]. Here, controllers are developed using an evolutionary algorithm based on the SGOCE encoding [31, 32] in which a genetic programming approach is used to evolve developmental programs that encode the growing of a dynamical neural network. The developmental programs determine how neurons located on a two-dimensional substrate produce new cells through cellular division and how they form efferent or afferent interconnections. Swimming controllers are generated when the growing networks eventually create connections to the muscles located on both sides of the rectangular substrate. These muscles are part of a two-dimensional mechanical simulation of the body of the lamprey in interaction with water. The motivation of this article is to develop a method for the design of control mechanisms for animal-like locomotion. Such a locomotion is characterized by a large number of actuators, a rhythmic activity, and the fact that efficient motion is only obtained when the actuators are well coordinated. The task of the control mechanism is therefore to transform commands concerning the speed and direction of motion into the signals sent to the multiple actuators. We define a fitness function, based on several simulations of the controller with different commands settings, that rewards the capacity of modulating the speed and the direction of swimming in response to simple, varying input signals. Central pattern generators are thus evolved capable of producing the relatively complex patterns of oscillations necessary for swimming. The best solutions generate traveling waves of neural activity, and propagate, similarly to the swimming of a real lamprey, undulations of the body from head to tail propelling the lamprey forward through water. By simply varying the amplitude of two input signals, the speed and the direction of swimming can be modulated.

Algorithms↗
PubMed2004

Assessment of the reproducibility of postprocessing dynamic CT perfusion data.

BACKGROUND AND PURPOSE: Commercially available software programs for the conversion of dynamic CT perfusion (CTP) source data into cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) maps require operators to subjectively define parameters that are used in subsequent postprocessing calculations. Our purpose was to define the variability of CBV, CBF, and MTT values derived from CTP maps generated from the same source data postprocessed by three different CT technologists (CTTs). METHODS: Raw data derived from dynamic CTP examinations performed in 20 subjects were postprocessed seven times by three experienced CTTs. Parenchymal regions of interest derived from each map (CBV, CBF, and MTT) were compared. The CBF maps generated by each technologist were also qualitatively assessed. Decisions made by each analyzer during postprocessing were assessed. RESULTS: The intraclass correlation coefficients were 0.73 (95% CI, 0.64-0.81), 0.87 (0.83-0.91) and 0.89 (0.85-0.93), for the CBV, CBF, and MTT parenchymal regions of interest, respectively. All individual correlation coefficients between data sets were significant to a P value <.05. Measurement error, made solely on the basis of different technologists postprocessing the same source data and expressed as the coefficients of variation, were 31%, 30%, and 14% for CBV, CBF, and MTT, respectively. The selection of the arterial input function (AIF) region of interest, venous function region of interest, and preenhancement interval were very reproducible. The technologists differed significantly with respect to the selection of the postenhancement image (PoEI) (P <.01). A retrospective review of the individual CBF maps indicated that variance in the PoEI selection accounted for much of the variation in the qualitative appearance of the CBF maps generated by different technologists. The PoEI was selected to demarcate the baseline of the AIF time-attenuation curve. It is likely that this method of PoEI selection significantly contributed to intra- and interanalyzer variability. CONCLUSION: There is a high degree of correlation between parenchymal regions of interest derived from CBV, CBF, and MTT maps generated from the same dynamic CTP source data postprocessed by different operators. The level of agreement, however, may not be sufficient to incorporate quantitative values into clinical decision making. Quantitative differences between parenchymal regions of interest were not infrequently manifest as significant differences in the qualitative appearance of the CBF maps. It is likely that, with optimization of postprocessing parameter selection, the degree of variability may be substantially reduced.

Arizona↗