De organische - stofhuishouding van grassportvelden

Aan de hand van gegevens uit de literatuur en uit eigen onderzoek wordt een kwalitatieve benadering gegeven voor de organische-stofhuishouding bij grassportvelden in de laag 0-5 cm. Hierbij is gebruik gemaakt van de door Kortleven (1963) ontwikkelde formules

Aspects of agricultural use of potato starch waste water.

Disposal of potato starch process water (average N, P2O5, K2O contents, 390, 140, 700 mg/l) on the land results in a high degree of purification. Complete purification is obtained in sandy soils if the rates do not exceed 100 to 150 mm/year. To maintain favourable conditions for biological decomposition of the organic matter the dose should be less than the water storage capacity of the soil. Disposal of the annual amount between a number of sprinkling irrigations is therefore recommended. Application rates can be adjusted to plant nutrient requirements. Optimum adjustment leads to an average yearly application of 25 mm yearly for the normal cropping pattern of the Peat Colonies. If excess supply is accepted the average value can be increased to 60 mm without harmful effects. From a computerized model study of the effect of the utilization of this waste water on farm economic results, the applications of 50 and 100 mm gave the highest returns.[227.7]. (Abstract retrieved from CAB Abstracts by CABI’s permission

The pathophysiological basis of pharmacological interventions in CAVD

Calcific aortic valve disease (CAVD) results in aortic valve stenosis and is one of the most common cardiac diseases in both Western and developing countries. The burden of this disease is expected to increase rapidly in the future, but there are still no relevant pharmacological therapies available and aortic valve replacement remains the sole definite therapy. This review presents an overview of the most common causes of CAVD, followed by current debates and trials related to the onset and progression of this disease. Several differences and similarities between the different causes of CAVD are presented. Additionally, stages of CAVD are compared with stages in atherosclerosis. Finally, future directions for research on CAVD will be discussed

Design and Implementation of an Architectural Framework for Web Portals in a Ubiquitous Pervasive Environment

Web Portals function as a single point of access to information on the World Wide Web (WWW). The web portal always contacts the portal’s gateway for the information flow that causes network traffic over the Internet. Moreover, it provides real time/dynamic access to the stored information, but not access to the real time information. This inherent functionality of web portals limits their role for resource constrained digital devices in the Ubiquitous era (U-era). This paper presents a framework for the web portal in the U-era. We have introduced the concept of Local Regions in the proposed framework, so that the local queries could be solved locally rather than having to route them over the Internet. Moreover, our framework enables one-to-one device communication for real time information flow. To provide an in-depth analysis, firstly, we provide an analytical model for query processing at the servers for our framework-oriented web portal. At the end, we have deployed a testbed, as one of the world’s largest IP based wireless sensor networks testbed, and real time measurements are observed that prove the efficacy and workability of the proposed framework

De betekenis van de zuurgraad van de grond en de fosfaat- en kalivoorziening van grassportvelden = The significance of soil pH and the supply of phosphorus and potassium to sports turf

In dit rapport worden de resultaten van eigen onderzoek omtrent de eisen die grasvelden aan de pH van de zodelaag en aan de voorziening met fosfaat en kali stellen, besproken en vergeleken met literatuurgegeven

Composteren van materialen die vrijkomen bij het beheer van heidevelden : Composting of materials resulting from heathland management

As heather materials contain relatively little easily decomposable organic matter, the composting process proceeds slowly. Composted heather materials have low contents of nutrients , a low electrical conductivity and a rather low p

Towards new therapies for calcific aortic valve disease

Calcific aortic valve disease (CAVD) is characterized by progressive calcification of the aortic valve cusps. The end-stage (stenosis), can lead to heart failure and death. Approximately 2-3% of adults over 65 years of age are thought to suffer from valve stenosis, requiring aortic valve replacement. This amounts to a total number of approximately 300,000 aortic valve replacements worldwide and this number is thought to triple by 2050. Currently used prostheses for heart valve replacement therapies are sub-optimal, mostly because they lack living tissue, hence the ability to grow and repair and remodel in vivo. Therefore, the search for alternative treatment options is warranted. In the first part of this thesis, we aimed to improve currently used strategies for heart valve tissue engineering. These strategies have been successfully applied in laboratory settings and even in pre-clinical animal models, but protocols need to be adapted for translation from bench to bedside. For this purpose, we have investigated if animal serum in culture protocols can be replaced with human plasma/serum alternatives. Our initial results showed that human platelet-lysate (PL) was a suitable substitute: use of PL resulted in enhanced cell proliferation, collagen production and expression of matrix metalloproteinases (MMPs) when compared to fetal bovine serum (FBS). The results from these 2D cell studies suggested that the use of PL would results in reduced waiting time to obtain sufficient amounts of cells, while subsequent tissue culture would benefit from enhanced collagen production and matrix remodeling. Unfortunately, a follow-up of this study in 3D-tissue strips revealed that tissue produced in PL-containing medium was significantly weaker when compared to tissue cultured in FSB-containing medium. Therefore, we hypothesized that human serum (HS) may be a more suitable alternative for FBS, because it should contain less platelet-derived growth factors which may induce expression and activity of MMPs. Indeed, in a third study, we showed that the use of HS instead of PL increased tissue strength to a level comparable to FBS. From these studies, we concluded that matrix remodeling by MMPs and the length and arrangement of collagen fibers are important determinants for tissue strength. Moreover, we showed that sequential use of PL and HS is an optimal autologous culture protocol for heart valve tissue engineering, as PL enhances cell proliferation, while HS stimulates production of load-bearing tissue. In the second part, we focused on future targets for pharmacological treatment of CAVD, which might halt progression of the disease, thereby preventing the need for invasive surgery. Following a review on etiology and pathogenesis of CAVD, we identified Wnt-signaling as a potential new target in onset and progression of CAVD. We describe a new pathway in valve tissue in which BMP2 stimulates Wnt-signaling, leading to enhanced expression of osteogenic transcription factor Runx2, independent of Smad-signaling. In the final chapter, we compare microRNA expression patterns from healthy and diseased valve tissue, resulting in identification of microRNAs possibly involved in CAVD. Future studies will be performed to determine if these studies result in new targets for future pharmacological treatments