3,415 research outputs found

    Particles adsorbed at various non-aqueous liquid-liquid interfaces

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    Particles adsorbed at liquid interfaces are commonly used to stabilise water-oil Pickering emulsions and water-air foams. The fundamental understanding of the physics of particles adsorbed at water-air and water-oil interfaces is improving significantly due to novel techniques that enable the measurement of the contact angle of individual particles at a given interface. The case of non-aqueous interfaces and emulsions is less studied in the literature. Non-aqueous liquid-liquid interfaces in which water is replaced by other polar solvents have properties similar to those of water-oil interfaces. Nanocomposites of non-aqueous immiscible polymer blends containing inorganic particles at the interface are of great interest industrially and consequently more work has been devoted to them. By contrast, the behaviour of particles adsorbed at oil-oil interfaces in which both oils are immiscible and of low dielectric constant (ε < 3) is scarcely studied. Hydrophobic particles are required to stabilise these oil-oil emulsions due to their irreversible adsorption, high interfacial activity and elastic shell behaviour

    Dilated Lymphatics in Gottron`s Papules

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    Advanced differentiation in trichoepithelioma and basal cell carcinoma investigated by immunohistochemistry against neurofilaments.

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    Basal cell carcinoma (BCC) and trichoepithelioma (TE) are sometimes diagnostic challenges for the pathologist in terms of their differential diagnosis. Although literature is quite rich in information about histologic and immunohistochemical clues to distinguish the differences between both, no single finding must be completely reliable. Moreover, some consider that TE is a better differentiated follicular tumour, while BCC represents a less developed stage in differentiation. For instance, the latter opinion is supported by the evidence of follicular papillae in TE.The formation of a perifollicular nerve plexus happens later than the formation of the follicular papillae in the development of a normal follicle. The study of the presence of the perifollicular nerve plexus in both tumours which could then provide us with evidence on the stage of differentiation of both tumours. 5 cases of TE and 10 cases of BCC were randomly selected from our archives and an immunohistochemical study for neurofilaments was performed in all the cases.We found a peritumoural nerve plexus in all the cases (TEs and BCCs). Since this plexus is a late sign of differentiation and since both types of neoplasias share it, we conclude that TE and BCC are both terminally differentiated neoplasms. The ability of BCC to infiltrate would have more to do with the acquisition by the tumour of such a property, rather than with a stage of indifferentiation

    Ökologische Bewertung von Bächen auf La Gomera und Teneriffa (Spanien) – ein methodischer Ansatz zur Einschätzung von Renaturierungsmaßnahmen bei der Umsetzung der EU-Wasserrahmenrichtlinie

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    In recent decades, the number of streams on the Canary Islands has decreased dramatically due to the non-sustainable consumption of water for agriculture and tourism. Natural reaches of streams with an endemic macroinvertebrate fauna do, however, still exist in protected areas of Tenerife and La Gomera. Those reaches serve as a reference to develop an assessment method for streams on islands. This method takes into account common parameters such as water quality and hydromorphology, while emphasizing biodiversity and endemism. The latter concepts as they relate to stream conservation are important in both nature conservation and protection of species as many endemic aquatic organisms are endangered.In den letzten Jahrzehnten ist die Zahl der Fließgewässer auf den Kanarischen Inseln drastisch zurückgegangen. Ursache dafür ist eine sehr hohe Wasserentnahme für Landwirtschaft und Tourismus, die das nachhaltig nutzbare Dargebot bei weitem überschreitet. Dennoch existieren in besonders geschützten Bereichen der Inseln Teneriffa und La Gomera noch naturnahe Abschnitte von Fließgewässern mit Elementen endemischer Makroinvertebraten-Fauna. Diese Abschnitte dienen als Referenzgewässer für die Entwicklung eines spezifischen Bewertungssystems für Fließgewässer auf Inseln. Dieses System berücksichtigt die üblichen Qualitätsparameter wie Wassergüte und Hydromorphologie, hebt aber die Biodiversität und den inseltypischen Endemismus besonders hervor. Die daraus resultierenden Gewässerentwicklungskonzepte stellen ein entscheidendes Instrument des Natur- und Artenschutzes dar, da viele der endemischen Gewässerorganismen vom Aussterben bedroht sind
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