PubMed Health⌕ Search

Biomedical subjects

E Eisenriegler

Publications and source records attributed to E Eisenriegler.

16 recordsLinked to original sources

Long flexible polymers interacting with ellipsoids, cylinders, and needles.

The depletion interactions of ellipsoidal colloidal particles in a solution of long polymer chains are analyzed. Of primary concern are the limiting cases in which the ellipsoid reduces to a cylinder of infinite length and finite radius and a "needle" of finite length and vanishing radius. Relations are obtained between the polymer effects induced by a needle that is much shorter than the polymer size and by a cylinder with radius much smaller than the polymer size. These imply exact quantitative results for the orientation-dependent depletion interaction between a short needle and a wall. Qualitative differences between the needle and thin disk are discussed.

Journal Article↗

Anisotropic colloidal particles interacting with polymers in a good solvent.

We study the consequences of chain self-avoidance for the interaction between nonadsorbing polymers and colloidal particles of anisotropic shape, such as ellipsoids, lenses, and dumbbells. In the framework of a field theoretic operator expansion for small mesoscopic particles, we obtain exact results for self-avoiding polymers in d=2 spatial dimensions and we compare ideal and self-avoiding polymers in 2<d<4. Changing the orientation of a particle, with a given size and shape, near a boundary wall requires less free energy if the chains are self-avoiding. The distance dependence of the anisotropic interation, mediated by the polymers between particle and wall, is changed both qualitatively and quantitatively by self-avoidance.

Journal Article↗

Anisotropic colloidal particles in critical fluids.

We consider anisotropic colloidal particles with dumbbell or lens shapes that are immersed in a critical binary fluid mixture. The orientation-dependent long-ranged universal interactions mediated by the critical solvent between a particle and a wall or between two particles are investigated for mesoscopic particle sizes small compared to the correlation length and interparticle distances. Exact results are obtained using a "small particle operator expansion." The amplitudes of the isotropic and anisotropic operators in the expansion depend on the size and aspect ratio of the dumbbell or lens and are determined by density profiles in the Ising model at the critical point in a wedge geometry with symmetry-breaking fixed-spin boundary conditions. Dumbbells and ellipsoids with a symmetry preserving surface are also considered.

Journal Article↗

[A set of questionnaires for the assessment (screening) of psychological disorders and social problems in cardiac rehabilitation patients].

A set of questionnaires for the assessment (screening) of psychological and social problems in cardiac rehabilitation patients is analyzed for its psychometric properties. The test battery had before been consented by a task force of the German Association for the Prevention and Rehabilitation of Cardiovascular Disease, DGPR. It integrates generally approved and well-tried assessments for depression/anxiety, social isolation (vocational) stress, and subjective vocational disability. The questionnaire was administered to a convenience sample of 426 patients undergoing inpatient cardiac rehabilitation. Results on the psychometric properties, a comparison of the cardiac sample to the general population, as well as distributions of quartile ranges are reported. Also, a preliminary appraisal of the need for further assessment or treatment is made. The results confirm that the short test battery is suited for assessing psychological and social problems in cardiac rehabilitation patients.

Adult↗

Polymer depletion effects near mesoscopic particles.

The behavior of mesoscopic particles dissolved in a dilute solution of long, flexible, and nonadsorbing polymer chains is studied by field-theoretic methods. For spherical and cylindrical particles the solvation free energy for immersing a single particle in the solution is calculated explicitly. Important features are qualitatively different for self-avoiding polymer chains as compared with ideal chains. The results corroborate the validity of the Helfrich-type curvature expansion for general particle shapes and allow for quantitative experimental tests. For the effective interactions between a small sphere and a wall, between a thin rod and a wall, and between two small spheres, quantitative results are presented. A systematic approach for studying effective many-body interactions is provided. The common Asakura-Oosawa approximation modeling the polymer coils as hard spheres turns out to fail completely for small particles and still fails by about 10% for large particles.

Journal Article↗

[Special aspects of physical training during the rehabilitation stage of coronary patients].

Practical aspects: Physical exercise is a basic component of the rehabilitation program for patients recuperating from myocardial infarction or bypass surgery. The aim of exercise is to enhance physical performance by improving coordination, flexibility, strength, speed and endurance. The training concept is matched to the individual capability, which is determined by an exercise test at the beginning of the rehabilitation program. On the basis of this test, an "exercise heart rate" is calculated with the aim of protecting the patient from overstrenuous activity. Depending on their physical fitness, the patients are divided into two groups: those with a capability of less, and those with a capability of more than 1 watt/kg. Most elderly patients are no longer active participants in sports, so that guidance through flexibility and coordination exercise is offered. Usually, patients perform a daily program of 15 minutes of physical activity in their individual groups, and spend 45 minutes walking and relaxing. In addition, they have opportunities for swimming, jogging and cycling. Decreased left-ventricular function: The effects of a four-week training program in myocardial infarction (MI) patients with moderate-to-severe left-ventricular dysfunction were investigated in two distinct studies. In neither study was a deterioration in the ejection fraction at rest or during exercise observed. In the second study, an additional parameter was provided by the Swan-Ganz catheter. Neither pulmonary wedge pressure (PWP) nor cardiac output indicated any deterioration in response to dosed training. However, in this second study, four patients in the training group with a resting ejection fraction (EF) less than 30% developed complications. All these patients had a pathological PWP at rest. Nevertheless, five patients with an EF less than 30% but with a normal PWP at rest completed the training program without complications. The long-term prognosis for training post-MI patients with severe left-ventricular dysfunction would appear to be no worse than for controls. Results of the first study: During the four-week training program, no complications occurred. No major changes in the EF at rest and during training were seen. In the training group the EF at rest increased slightly to 40 +/- 10%. The EF during exercise improved to 39 +/- 10%. Delta EF showed a decrease of 3 +/- 8%. After the four-week training period the decrease was 1 +/- 9%. In the control group, a major increase in the EF at rest to 41 +/- 10% was seen. The EF during exercise, however, showed only a small increase to 43 +/- 15%.(ABSTRACT TRUNCATED AT 400 WORDS)

Coronary Disease↗

[A survey of the medical and psychosocial status of 140 workers 32 months following myocardial infarct].

We suspected there could be different social, psychological, and medical problems for women after a first myocardial infarction than those affecting men. 140 women (56.4 +/- 7 years) were interviewed by questionnaire 32 +/- 8.7 months after myocardial infarction; 83% (n = 119) responded (8.8% of the sample group had died), 12% suffered a reinfarction, and 11% underwent aortocoronary bypass surgery. For 84% of those responding it was harder to do their housework after myocardial infarction, but 73% did it without help. 51.5% showed a mood change that included increasing depression, anxiousness, and insecurity. In 12.5% of the women their relationship with their husband was adversely affected; in 6.6% their relationship with their children worsened. 83% (n = 89) saw their infarction as a result of stress. 45% could not relieve their stress after 32 months. A subjective feeling of stress decrease in 54% was achieved with a quieter life, in 39.5% by resigning their jobs, and in 6.5% by the death of the husband. Concerning somatic risk factors 74% of the smokers stopped smoking; oral contraceptives were discontinued in all cases. 90.5% (n = 97) of the women said they had their serum lipid values checked regularly, but these were only under control in 35%. We conclude the rehabilitation process does not end when patients leave a rehabilitation clinic. Patients should acquire household help, and their family situation should be discussed during their stay in the rehabilitation clinic. Concerning the somatic risk factors, women who survive myocardial infarction require better care and information.

Adult↗