Downstream changes in the composition,numbers and biomass of bottom fauna in the Tees below Cow Green Reservoir and in an unregulated tributary Maize Beck,in the first five years after impoundment

Changes in composition, numbers and biomass of benthic fauna of the Tees below Cow Green Reservoir and an unregulated tributary Maize Beck were followed between 1972 and 1975 and pre- and post-impoundment conditions were compared. Species diversity was lowest just below the dam and numbers and biomass were highest 240 m downstream of the dam. Faunal densities increased in the Tees after impoundment but in Maize Back no major changes were observed.Freshwater Biological Association, Cow Green UnitFreshwater Biological Association, Cow Green Unit     

A review of allograft ophthalmic tissue in eye surgery

Transplanting human tissue to the front of the eye has been practiced for over 100 years. Contiguous corneal layers may be transplanted separately (lamellar keratoplasty) or together (full thickness or penetrating keratoplasty). The former methods are gaining in popularity, replacing full thickness transplants. Reasons for transplantation and current practice and techniques are described with respect to their impact on vision, and associated adverse events.     

Seleno-dl-methionine reduces freezing injury in hearts protected with ethanediol

Perfusion of whole rabbit hearts with solutions containing 20 μg/liter seleno-dl-methionine improved the cryoprotection afforded by ethanediol (3 mol/liter) during freezing at ?15 °C. In five of the six hearts frozen with seleno-dl-methionine, all of the chambers contracted after rewarming and removal of ethanediol, whereas in hearts frozen without selenium, only one or two chambers showed any activity. The vascular resistance in hearts from both groups increased approximately sixfold during the removal of the cryoprotectant, indicating severe vascular damage. The left ventricle, the interventricular septum and the papillary muscles suffered the greatest decrease in perfusion after freezing. Although vascular damage was severe, selenium apparently increased the tolerance of the myocardial cells to freezing.     

A highly alkaline Lake in Nicaragua

Zusammenfassung Der Nejapa-See liegt in einem vulkanischen Krater. Sein pH übertrifft 10; die Bikarbonat-Alkalinität betrug 4.39 g/l, die Karbonat-Alkalinitat 10.44 g/l. Vier Blaualgenarten wurden gefunden, jedoch kein Zooplankton.