Graphical abstract

Using confocal microscopy in conjunction with microdrop application of Dil, we have imaged and measured individual dendritic spines of living hippocampal CA1 pyramidal neurons in acute brain slices, before and approximately 3 hr after induction of long-term potentiation by chemical means. Statistical analysis of changes in the length of individual spines, and comparison with results of Monte Carlo simulations, suggests that two forms of structural change occur in chemically induced long-term potentiation: growth of a subpopulation of small spines, and angular displacement of spines. These changes could provide a structural basis for the expression of long-term potentiation.

No abstract

To compare water quality in rivers of developed and developing countries, a study based on physicochemical parameters and dissolved metals levels was conducted. Water samples were collected from selected sites in Dhaka, Bangladesh; Hokkaido and Osaka, Japan; Erdenet, Mongolia and West Java, Indonesia. Analysis of least significant differences revealed that most water quality parameters were within comparable low levels in both developed and developing countries. The dissolved metals concentrations were found to be similar and below those of water standards except for manganese and cadmium at every sampling point, and lead in Erdenet, Mongolia. Some metals showed high enrichment factors in the rivers of Osaka, Japan and Erdenet, Mongolia, indicating accumulation possibility of metals in the river-bed sediments. High concentrations of dissolved organic carbon, Escherichia coli and dissolved metals suggested greater water pollution in some rivers of developing countries than in the rivers of Japan. Principal component analysis showed strong correlations between “dissolved organic carbon and chemical oxygen demand” and “conductivity and total dissolved solids” at each sampling point, and E. coli, nitrate (NOmath image), nitrite (NOmath image), and pH levels were found to be higher in the rivers of Dhaka and Erdenet. In addition, there were high levels of Al and Zn in West Java, Pb in Erdenet, and Mn, Fe, and Cr in the rivers of Dhaka and Japan. Based on pressures and impacts, it is evident that dissolved metal, organic, and fecal pollution in the rivers of developing countries are in somewhat dreadful condition in comparison with the rivers of developed country

No abstract