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Biomedical subjects

E Kats

Publications and source records attributed to E Kats.

7 recordsLinked to original sources
PubMed2006

Stabilization of membrane pores by packing.

We present a model for pore stabilization in membranes without surface tension. Whereas an isolated pore is always unstable (since it either shrinks, tending to reseal, or grows without bound until membrane disintegration), it is shown that excluded volume interactions in a system of many pores can stabilize individual pores of a given size in a certain range of model parameters. For such a multipore membrane system, the distribution of pore size and associated pore lifetime are calculated within the mean-field approximation. We predict that, above the temperature T(m), when the effective line tension becomes negative, the membrane exhibits a dynamic sievelike porous structure.

Journal Article↗
PubMed2004

Bubble relaxation dynamics in double-stranded DNA.

This paper deals with the two-state (opening-closing of base pairs) model used to describe the fluctuation dynamics of a single bubble formation. We present an exact solution for the discrete and finite size version of the model that includes end effects and derive analytic expressions of the correlation function, survival probability, and lifetimes for the bubble relaxation dynamics. It is shown that the continuous and semi-infinite limit of the model becomes a good approximation to an exact result when aN <<1, where N is bubble size and a, the ratio of opening to closing rates of base pairs, is the control parameter of DNA melting.

Base Sequence↗
PubMed2001

Disjoining pressure and thinning transitions in smectic-A liquid crystal films.

The contact angle between a free standing film of a smectic-A liquid crystal and its meniscus is different from zero. It increases independently of the meniscus size when the film thickness decreases. This angle provides a very precise measurement of the film tension and of the interactions between the two free surfaces. This interaction is attractive and can be qualitatively explained within the framework of the de Gennes theory of the presmectic state. According to this model, the attraction is caused by an increase of the smectic order parameter at the free surface. This phenomenon also explains the metastability of very thin smectic films above the bulk smectic-A-nematic phase transition. The temperatures T(N) of spontaneous thinning from N layers to N-1 layers is measured in the smectic phase of the liquid crystal 8CB (octylcyanobiphenyl).

Journal Article↗
PubMed1992

Culturalizing the ethnic patient: educational films and images of interethnic relations in health care.

In the wake of an apparent increased utilization of health services by people from ethnic minorities and the perceptions of this as problematic, an educational 'offensive' has been launched in The Netherlands. It is directed at ethnic minority groups and health care professionals, and makes extensive use of educational films. In this article, we discuss results of a qualitative analysis of the ways in which educational films represent interethnic relations in health care, and compare them with the outcomes of an earlier analysis of educational films on discrimination and racism. Instead of a tendency to moralize ethnic attitudes of whites in the latter, we found that films on health care presuppose a professional will to learn and to adapt, but at the same time they emphasize the obstacles posed by ethnic backgrounds. In such films, the traditional culture, rather than institutional constraints, figures as the main reason for the setbacks the ethnic patient experiences and for the problems professionals face in order to accommodate the new situation. Educational films on ethnic minorities and health (care) could be improved by analysing problems rather than focusing on ready-made solutions, and by paying attention to institutional constraints rather than showing a seemingly boundless flexibility of medical professionals in their interaction with ethnic minorities.

Culture↗
PubMed1991

Sixty-three cases of traumatic injury of the diaphragm.

In the examination of patients with severe thoracic and/or abdominal trauma not requiring surgical exploration, special attention should be given to signs of traumatic diaphragmatic herniation (TDH). We analysed the hospital records of 63 patients with traumatic injuries of the diaphragm. Of these patients, 39 had suffered a blunt trauma in a traffic accident, 21 penetrating trauma, and three had fallen from a great height. There were 51 patients (81 per cent) with left-sided diaphragmatic injuries, ten (16 per cent) with right-sided injuries, and in two patients (3 per cent) the injuries to the diaphragm were bilateral. There were 22 patients (35 per cent) who had intrathoracic migration of abdominal viscera. Surgical treatment was given in all cases. Twelve patients (19 per cent) died due to massive haemorrhage, neurological lesions, or septicaemia. Based on the literature and our own experience, we developed a diagnostic protocol for the management of diaphragmatic injuries. Chest radiographs should be made routinely. If diaphragmatic injury is suspected, ultrasound investigation must be performed. If the physician is still in doubt, computed tomography should be performed. At laparotomy, the diaphragm should always be thoroughly examined for lacerations.

Abdominal Injuries↗