Viscosity changes of synovia after application of water treated with ultrasound

Zusammenfassung Nach Applikation von beschalltem Wasser wurde infolge physikochemischer Degradation der Polysaccharide ein Viskositätsabfall der Synovia nachgewiesen.     

Oxidative activity of limbic structures during sexual cycle in rats

Resumen Se ha estudiado el consumo de oxígeno de la amigdala y del hipocámpo en ratas hembras durante el ciclo sexual. La corteza cerebral se utilizó como control. Los resultados obtenidos indican que ambas estructuras límbicas sufren cambios ciclicos. La mayor actividad metabólica de la amigdala fué observada durante el estro en cambio el hipocampo tiene su mayor consumo de oxígeno durante el diestro.

---

---

Supported by a grant of Fundacón Marqués de Urquijo.     

Action of tobacco on lipolysis and its modification by insulin

Resumen Los fumadores habituales tienen niveles de FFA significantivamente más altos que los no fumadores. El acto de fumar incrementa la lipolisis. Fumar sin inhalar el humo produce incremento de lipolisis. La insulina inhibe la accion lipolítica del humo de tabaco.     

A record of Permian subaqueous vent activity in southeastern Brazil

The remarkable occurrence of more than 4,500 conical siliceous mounds in an area of less than 1.5 square kilometres has been reported in the Paraná basin, near Anhembi, S?o Paulo, in southeastern Brazil. These structures, which are up to two metres high, are thought to have been formed at the margin of a very shallow, broad but waning internal sea, and it was originally suggested that they are stromatolites. Yet their restricted occurrence, unusual abundance and nearly pure siliceous composition have never been satisfactorily explained by this hypothesis. Here we report field and laboratory observations on their shape, construction, composition and mineralogy. On the basis of our data we suggest that the conical mounds are the result of subaqueous Late Permian vent activity in southwestern Gondwana. The present siliceous cone field differs considerably from other Palaeozoic siliceous hot spring deposits, such as those at Rhynie, Scotland, and the Drummond basin, Australia, and therefore represents an unusual occurrence of vent activity.     

The obscuration by dust of most of the growth of supermassive black holes

Supermassive black holes underwent periods of exponential growth during which we see them as quasars in the distant Universe. The summed emission from these quasars generates the cosmic X-ray background, the spectrum of which has been used to argue that most black-hole growth is obscured. There are clear examples of obscured black-hole growth in the form of 'type-2' quasars, but their numbers are fewer than expected from modelling of the X-ray background. Here we report the direct detection of a population of distant type-2 quasars, which is at least comparable in size to the well-known unobscured type-1 population. We selected objects that have mid-infrared and radio emissions characteristic of quasars, but which are faint at near-infrared and optical wavelengths. We conclude that this population is responsible for most of the black-hole growth in the young Universe and that, throughout cosmic history, black-hole growth occurs in the dusty, gas-rich centres of active galaxies.     

Tumour biology: senescence in premalignant tumours

Oncogene-induced senescence is a cellular response that may be crucial for protection against cancer development, but its investigation has so far been restricted to cultured cells that have been manipulated to overexpress an oncogene. Here we analyse tumours initiated by an endogenous oncogene, ras, and show that senescent cells exist in premalignant tumours but not in malignant ones. Senescence is therefore a defining feature of premalignant tumours that could prove valuable in the diagnosis and prognosis of cancer.