Mixed-species plantations of eucalyptus with nitrogen fixing trees: a review

Mixed-species plantations of Eucalyptus with a nitrogen (N2) fixing species have the potential to increase productivity while maintaining soil fertility, compared to Eucalyptus monocultures. However, it is difficult to predict combinations of species and sites that will lead to these benefits. We review the processes and interactions occurring in mixed plantations, 5 and the influence of species or site attributes, to aid the selection of successful combinations of species and sites. Successful mixtures, where productivity is increased over that of monocultures, have often developed stratified canopies, such that the less shade-tolerant species overtops the more shadetolerant species. Successful mixtures also have significantly higher rates of N and P cycling than 10 Eucalyptus monocultures. It is therefore important to select N2-fixing species with readily decomposable litter and high rates of nutrient cycling, as well as high rates of N2-fixation. While the dynamics of N2-fixation in tree stands are not well understood, it appears as though eucalypts can benefit from fixed N as early as the first or second year following plantation establishment. A meta-analysis of 18 published studies revealed several trials in which mixtures were significantly 15 (

Modular independent metering system for mobile applications providing smooth mode transition

Independent metering valve systems open up for more flexibility because of the ability to control meter in and meter out flow individually, thus enabling many possibilities to adapt the actuator s behaviour to the user´s needs without altering any hardware. Furthermore, with alternative flow modes significant energy savings are possible. In many applications like excavators smooth switching between flow modes is required, a demand the market does not provide a satisfying solution for yet. Here, an approach using a short circuit path for smooth switching has been developed. The control algorithm hands over the volume flow from one path to another continuously depending on the current actuator load. Due to the flexible software structure the developed control algorithm can be applied to a very broad variety of independent metering valve layouts. Simulation results are promising and currently the solution is undergoing test rig evaluation

Modular independent metering system for mobile applications providing smooth mode transition

Independent metering valve systems open up for more flexibility because of the ability to control meter in and meter out flow individually, thus enabling many possibilities to adapt the actuator s behaviour to the user´s needs without altering any hardware. Furthermore, with alternative flow modes significant energy savings are possible. In many applications like excavators smooth switching between flow modes is required, a demand the market does not provide a satisfying solution for yet. Here, an approach using a short circuit path for smooth switching has been developed. The control algorithm hands over the volume flow from one path to another continuously depending on the current actuator load. Due to the flexible software structure the developed control algorithm can be applied to a very broad variety of independent metering valve layouts. Simulation results are promising and currently the solution is undergoing test rig evaluation

Priming of T cells with Ad-transduced DC followed by expansion with peptide-pulsed DC significantly enhances the induction of tumor-specific CD8+ T cells : implications for an efficient vaccination strategy

In recent years, vaccination strategies using antigen-presenting cells (APC) have been under investigation. Antigen delivery using genetic immunization through ex vivo transduction of dendritic cells (DC) is supposed to enhance the induction of antitumor responses in humans by activating a broad range of peptide-specific CD8+ T cells. In this study, we compared the potential of adenoviral (Ad)-transduced versus peptide-pulsed DC to induce melanoma-antigen (Ag)-specific T-cell responses in vitro. Whereas gp100-peptide-pulsed DC induced long-lasting specific CD8+ T-cell responses against single peptides, Ad-transduced DC induced broad and strong, specific immunity against various peptides of the gp100-Ag. Surprisingly, several restimulations led to decreasing gp100-specific and in parallel to increasing anti-adenoviral T-cell responses. Nevertheless, those anti-adenoviral T-cell responses provided an %22adjuvant%22 effect by inducing an early release of high amounts of IL-2/IFN-gamma, therewith enhancing CTL induction in the initiation phase. Based on these data, we suggest a prime/boost vaccination strategy in melanoma patients--combining the use of Ad-DC and peptide-pulsed DC--to obtain efficient and long-term antitumor T-cell responses

Efficient transduction of mature CD83+ dendritic cells using recombinant adenovirus suppressed T cell stimulatory capacity

We have developed a culture method for the foreign serum-free generation of highly immunostimulatory, CD83+ human dendritic cells (DC). In this study, we evaluated the feasibility and consequences of endogenously expressing antigens in mature DC using adenoviral vectors. Transduction of DC with Ad-EGFP demonstrated endogenous fluorescence in 50-85% of CD83+ DC. Ad-transduced DC stimulated the proliferation of allogeneic CD8+ and CD4+ T cells at low DC: T cell ratios. However, at high DC: T cell ratios the stimulatory capacity of Ad-transduced DC was suppressed. This immunosuppressive effect was confirmed by demonstrating that the stimulatory function of untreated DC could be suppressed in a dose-dependent manner by addition of Ad-transduced DC. Furthermore, transwell experiments suggested that direct cell contact was required. Taken together, our results demonstrate the feasibility of efficiently expressing antigens in CD83+ DC using adenoviruses. However, immunosuppressive effects must be considered and carefully studied before Ad-transduced DC are employed for clinical trials. Gene Therapy (2000) 7, 249-254