Layer Buildup on Two-Layered Porous Substrate by Dip-Coating: Modeling and Effect of Additives on Growth Rate.

A model was developed to describe layer buildup on a two-layered substrate during dip-coating. In this model, the growth rate can be used to estimate the permeability of the cast layer. Layers of submicron alumina were dip-coated onto the asymmetric porous substrate to evaluate the model. The layer buildup and properties were studied with different slip additives. Slips were deflocculated with nitric acid or sodium poly(methacrylic acid) (Na-PMAA) to achieve electrostatic or electrosteric stabilization. Properties of the slips with electrostatic stabilization were varied with poly(vinyl alcohol) (PVA) concentration. Properties of the slips with electrosteric stabilization were varied with Na-PMAA concentration. PVA addition decreased the growth rate of the layer by reducing capillary pressure and increasing the viscosity of the filtrate. Electrostatic stabilization of the slip with PVA addition also led to almost complete deflocculation and a rather high density of layers. Na-PMAA addition led to fast growth of the layer. Na-PMAA addition increased the capillary pressure and had a minor effect on the viscosity of the liquid phase. Na-PMAA addition led to an incomplete dispersion of particles and therefore a high porosity of layers. Permeability values of coated layers obtained from the model were compared with permeability values predicted by the Kozeny-Carman equation. In the case of complete deflocculation of the slip, the permeability values estimated with the model correlated reasonably well with the predicted values. Incomplete deflocculation led to higher permeability values than predicted by the Kozeny-Carman equation. Copyright 2000 Academic Press.

Haemodynamic results of femoropopliteal percutaneous transluminal angioplasty.

OBJECTIVES: To determine the utility of percutaneous transluminal angioplasty (PTA) of the femoropopliteal segment in patients with claudication and critical leg ischaemia (CLI). DESIGN: Longitudinal observational study. SETTING: A university based vascular surgical centre. MATERIAL: Ninety-five patients with stenosing or occlusive arterial lesions of the femoropopliteal segment underwent 52 primary PTA for claudication and 50 primary PTA for CLI. METHODS: The procedure was considered haemodynamically successful when the increase of immediate postprocedural ABI was 0.15 or more. The criterion for haemodynamic success during follow-up was an ABI having not decreased by more than 0.15 from the immediate postprocedural level. The run-off arteries were graded according to the scoring system proposed by the SVS/ISCVS. RESULTS: Among the technically successful procedures (83%), the haemodynamic success rate was 77% at 1 month, 55% after 1 year, and 51% after 2 years. The cumulative haemodynamic success rates were 83%, 66% and 61% in claudicants, and 70%, 42%, and 38% in CLI (p = 0.03). In patients with a run-off score < or = 7.5, the success rates were 84%, 67%, and 60%, respectively, whereas in those with a crural score > 7.5 these were 61%, 39%, and 39%, respectively (p = 0.04). CONCLUSIONS: The haemodynamic results suggest that PTA to the femoropopliteal segment is seldom a procedure of choice for critically ischaemic legs with poor run-off. The run-off score is useful in identifying patients who may benefit from PTA.

Passive immunization with monoclonal antibodies specific for lipopolysaccharide (LPS) O-side chain protects mice against intravenous Yersinia enterocolitica serotype O:3 infection.

Passive immunization with monoclonal antibodies specific for the lipopolysaccharide (LPS) O-side chain protected mice against intravenously given lethal doses of Yersinia enterocolitica O:3 bacteria. On the other hand, passive immunization with monoclonal antibody specific for the LPS core oligosaccharide did not protect mice. Neither antibody was able to protect mice against orally given lethal doses of bacteria. These results indicate that the O-side chain functions as an important antigenic structure during infection, and that immunity to it probably offer protection also in the in vivo situation.

Coordinate-based mapping--a new method in health services research.

The Finnish national hospital discharge registers from 1985 and 1988 have been analysed by the National Board of Health. Results are provided for all the 21 Finnish hospital districts and central communal organizations. The small area variation phenomenon in hospital utilization cannot be explained by demographic or epidemiological factors. Rather, the variations seem to be largely due to organizational factors. The project aims to develop a data processing system capable of handling information on one million patients rapidly and economically, and show the results in an intelligible form as a table with standard headers or as a map illustration. Maps are superior to traditional statistical tables in demonstrating regional variations in health care utilization and in mortality. Maps based on small administrative units are useful for many purposes. These maps are, however, relatively 'noisy' due to substantial random variation. Coordinate-based mapping is a method to overcome some of these difficulties. It is based on linking hospital discharge and mortality data with exact address data. The method allows mapping independent of administrative boundaries. Several examples of coordinate-based maps are given. The method is used in Finland for annual analysis of hospital use.

Clinical manifestations of Yersinia pseudotuberculosis infection in children.

The clinical manifestations of infection were analysed during an outbreak of 34 cases of Yersinia pseudotuberculosis serotype Ia infection. The diagnosis was based on the results of enzyme immunoassay and verified by stool culture in five cases. The first four patients were pupils from the same school, and information on any signs and symptoms of infection was obtained by questionnaire from pupils of the school. A blood sample was obtained from 101 children. Strong IgM and IgG antibody responses to Yersinia pseudotuberculosis Ia were found in 13 (25%) of the 52 pupils who reported signs and symptoms of infection and in 9 (18%) of the 49 with no manifestations of infection. The vigorous immune response also resulted in effective opsonization of the causative microorganism. The most common symptoms were fever and abdominal pain. Three children operated on because of suspected appendicitis were found to have mesenteric lymphadenitis. Only one patient developed reactive arthritis. Analysis showed that a remarkable proportion of Yersinia pseudotuberculosis infections may be subclinical, and that individual Yersinia pseudotuberculosis strains may have different capacities to cause postinfection complications.