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

Sequential use of human-derived medium supplements favours cardiovascular tissue engineering

For clinical application of tissue engineering strategies, the use of animal-derived serum in culture medium is not recommended, because it can evoke immune responses in patients. We previously observed that human platelet-lysate (PL) is favourable for cell expansion, but generates weaker tissue as compared to culture in foetal bovine serum (FBS). We investigated if human serum (HS) is a better human supplement to increase tissue strength. Cells were isolated from venous grafts of 10 patients and expanded in media supplemented with PL or HS, to determine proliferation rates and expression of genes related to collagen production and maturation. Zymography was used to assess protease expression. Collagen contraction assays were used as a two-dimensional (2D) model for matrix contraction. As a prove of principle, 3D tissue culture and tensile testing was performed for two patients, to determine tissue strength. Cell proliferation was lower in HS-supplemented medium than in PL medium. The HS cells produced less active matrix metallo-proteinase 2 (MMP2) and showed increased matrix contraction as indicated by gel contraction assays and 3D-tissue culture. Tensile testing showed increased strength for tissues cultured in HS when compared to PL. This effect was more pronounced if cells were sequentially cultured in PL, followed by tissue culture in HS. These data suggest that sequential use of PL and HS as substitutes for FBS in culture medium for cardiovascular tissue engineering results in improved cell proliferation and tissue mechanical properties, as compared to use of PL or HS apart

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

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

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