Long-term stabilization of N-labeled experimental NH deposition in a temperate forest under high N deposition.

High nitrogen (N) deposition levels, currently present in many industrial and agricultural regions of the world, can strongly affect the functioning of forest ecosystems. In a pine forest with strong N leaching, located in the Netherlands, we studied the long-term fate of a year-long NH deposition cohort labeled with N. A high ambient and a low N deposition treatment had been established at the site by means of a roof and sprinklers.

Ecosystem responses to reduced and oxidised nitrogen inputs in European terrestrial habitats.

While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NH(x) and NO(y)) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and reduced nitrogen inputs are occurring, this oversight requires attention. One reason for this knowledge gap is that plants experience a different NH(x):NO(y) ratio in soil to that seen in atmospheric deposits because atmospheric inputs are modified by soil transformations, mediated by soil pH.

Long term changes in atmospheric N and S throughfall deposition and effects on soil solution chemistry in a Scots pine forest in the Netherlands.

In a Scots pine forest the throughfall deposition and the chemical composition of the soil solution was monitored since 1984. (Inter)national legislation measures led to a reduction of the deposition of nitrogen and sulphur. The deposition of sulphur has decreased by approximately 65%.

The bioseparation needs for tomorrow.

Will we replace oil with wheat or corn as a feedstock for producing natural plastic? The success of biotechnology for bulk product manufacturing will heavily depend on engineering solutions in the downstream processes in which separation and purification have a crucial role with respect to commercial development. Development of efficient bioseparation methods is important for a broad range of business areas including pharmaceuticals, nutrition and health products, bio-based materials and crop protection chemicals. Depending on the value of the end product and the scale of production, the processing required varies significantly.

Does (K+Mg+Ca+P) fertilization lead to recovery of tree health in a nitrogen stressed Quercus rubra L. stand?

In The Netherlands atmospheric deposition of nitrogen compounds to forest ecosystems has been very high for some decades and has led to severe nutritional imbalances in soils as well as in trees. At this moment legislation is not fully in effect with respect to lowering emission/deposition fluxes, particularly of nitrogen. The trees suffer mainly from severe magnesium, potassium and calcium and sometimes phosphorus deficiencies.

Deconvolution of light-scattering patterns by observing intensity fluctuations.

Results are presented on the statistical fluctuations occurring in a forward-light-scattering experiment to determine the particle size distribution. A sample of glass beads was measured using a Malvern 2600D instrument and analyzed with a proposed deconvolution procedure that incorporates the observed intensity fluctuations. This procedure yields a qualitative improvement of the solution, provides error intervals, and offers a better means for model discrimination.

Effects of ammonium and aluminium on the development and nutrition of Pinus nigra in hydroculture.

Application of ammonium and aluminium to young Pinus nigra var. maritima (Ait.) Melville trees resulted in a variety of negative effects.

A study of the mechanism by which inhibitors of the plasmamembrane ATPase enhance uptake of divalent cations in yeast.

The enhancement of divalent cation uptake in yeast provoked by the membrane ATPase inhibitors trifluoperazine, miconazole, compound 48/80, ethidium, DIO-9 and calmidazolium should be ascribed to an increase in cation permeability of the yeast rather than to hyperpolarisation of the yeast cell membrane. For trifluoperazine and miconazole it is unequivocally shown that the cells are hyperpolarized though for miconazole only transiently. Whether the other drugs also hyperpolarize the yeast cells is uncertain.

Possible energization of K+ accumulation into metabolizing yeast by the protonmotive force. Binding correction to be applied in the calculation of the yeast membrane potential from tetraphenylphosphonium distribution.

Membrane potentials of yeast cells, Saccharomyces cerevisiae, calculated from the equilibrium distribution of tetraphenylphosphonium (TPP) between cell-water and medium should be corrected for a contribution due to binding of TPP to intracellular constituents. The magnitude of this correction depends upon the way in which it is determined. In cells permeabilized by boiling, cell-binding is much higher than in cells permeabilized by repeated freezing and thawing.

Some characteristics of tetraphenylphosphonium uptake into Saccharomyces cerevisiae.

The characteristics of the uptake of the lipophilic cation tetraphenylphosphonium (TPP+) into Saccharomyces cerevisiae have been investigated in order to establish whether this compound can be used to monitor the membrane potential of his organism. Unlike dibenzyldimethylammonium, TPP+ is not translocated via the thiamine transport system, nor via another inducible translocation mechanism. On changing the experimental conditions the equilibrium potential of TPP+ varies according to expected changes of the membrane potential.