Zn–Al layered double hydroxides as chloride nanotraps in active protective coatings

Zn–Al layered double hydroxides (LDHs) intercalated with nitrate anions are suggested as chloride nanotraps for organic polymeric coatings. The addition of such nanotraps to a polymer layer drastically reduces the permeability of corrosive chloride anions through the protective coatings. In solution, Zn(2)–Al–NO₃ LDHs are responsive to the concentration of chlorides and the release of nitrates is accompanied by entrapment of chlorides, with the process governed by ion-exchange equilibrium. In particular, a coating modified with LDH–NO₃ was found to exhibit significantly lower permeability to chlorides when compared to both unmodified and LDH–Cl-containing coatings, which proves the applicability of LDHs in delaying coating degradation and corrosion initiation.     

In-situ contact angle studies of the release of water displacing agents from capsule filled organic coatings

Protective coatings containing polymer microcapsules loaded with water displacing alkoxysilanes were studied by means of a new apparatus allowing the study of advancing and receding contact angles during the simultaneous stretch forming of the coated substrate. FE-SEM studies were performed after stretch forming to correlate the defect structure with the process of hydrophobization. It could be shown that the incorporation of alkoxysilane loaded polymer capsules into a coating system led to a pronounced hydrophobization of cracks that were formed during the stretching of the sample. The local hydrophobization is assigned to the conversion of alkoxysilanes to polysiloxanes via hydrolysis and condensation which are initiated by the contact of those alkoxysilanes with the aqueous electrolyte during water attack.     

Problems of distinction of normal, arteficial and pathological structures in mature human placental villi. III. Morphometric studies in rhesus incompatibility (author's transl)

Sections of human placental villi which were up to 80 micrometer in diameter were examined light microscopically and morphometrically. The villi were obtained by taking an aspiration biopsy of the attached placenta from 20 normal patients at term and from eight patients delivered at or before 37 weeks because of varying degrees of rhesus incompatibility. The distribution of three histological types of villi was determined. The intermediate villi from patients with erythroblastosis showed an increase in number and volume matching the severity of the disease. The intermediate villi also showed an increase in the amount of cytotrophoblasts, in the amount of materno-fetal diffusion surface area, in the thickness of syncytium, and in the number of Hofbauer cells. The terminal villi were not affected by erythroblastosis and the mature end villi showed a relative decrease in number. To obtain these results an optimal fixation technique was required.     

Repeated administration of a F(ab')2 fragment of an anti-tumor necrosis factor alpha monoclonal antibody in patients with severe sepsis: effects on the cardiovascular system and cytokine levels

In an uncontrolled clinical trial the effects of repeated administration of the F(ab')2 fragment of a murine monoclonal anti-tumor necrosis factor alpha (TNF alpha)-antibody (MAK 195F) on cytokine levels and the cardiovascular system were studied in 20 patients with severe sepsis. Patients were treated with a total of 11 single dosages of the anti-TNF alpha-antibody intravenously over 5 days using either 1 mg/kg (n = 10) or 3 mg/kg (n = 10). The anti-TNF alpha-antibody was well tolerated in all patients without signs of toxicity and without development of anti-murine antibodies. As assessed by cytokine levels (TNF alpha, Interleukin-6) and hemodynamics there was no evidence that the higher dosage of the anti-TNF alpha-antibody (3 mg/kg per dose) was more effective than the lower dosage (1 mg/kg per dose). Comparison of our data with recent data from phase I or II trials using a complete murine monoclonal anti-TNF alpha-antibody suggest that the F(ab')2 fragments of the murine monoclonal anti-TNF alpha-antibody may be of similar efficacy. Definitive conclusions, however, with respect to improvement of mortality and improvement of the cardiovascular system, await the results of larger ongoing placebo-controlled trials.     

Verfahren zur Bildung von Personal- und Arbeitsplatzgruppen für Disposition und Planung

Beschreibung der Anforderungen am Arbeitsplatz und der Fähigkeiten des Personals durch die merkmalsweise Arbeitsplatzanalyse. Unterschiedliche Merkmalskonstellationen erfordern die Bildung von Personal- und Arbeitsplatzgruppen. Verfahren zur Objektivierung der Gruppenbildung für die betriebliche Disposition und Planung am Arbeitsplatz.     

Risikoermittlung und Sicherheitsanalysen in der chemischen Technik

Risk assessment and safety analysis in chemical engineering . There are in principle two possible ways of assessing the risks originating from industrial plants: the empirical method, which tries to directly evaluate experience from actual hazards and their consequences in the past, and the theoretical-analytical method, which – in so called risk analyses – uses extensive model calculations to deduce risk values from the interrelationship between minor disturbances and major hazards and their possible consequences. It is shown that in the chemical industry reliable results can only be expected from the empirical method, since indispensable prior conditions for the application of risk analysis methods are not given in operating chemical plants. Because of the considerable degree of uncertainty, theoretically assessed values for risk should not – in the chemical industry – be used for decisions. Empirical risk assessment on the other hand is reliable and makes it clear that the risk from chemical activities is fairly low as compared to other natural and manmade risks for both employees of chemical industries and people living near industrial sites. This is, no doubt, the clear result of the consequent use of hazard and safety analysis methods during the planning and development of chemical plant.