83 research outputs found
Renewable Energy
This chapter presents an in-depth examination of major renewable energy technologies, including their installed capacity and energy supply in 2009 , the current state of market and technology development, their economic and financial feasibility in 2009 and in the near future,
as well as major issues they may face relative to their sustainability
or implementation. Renewable energy sources have been important for humankind since the beginning of civilization. For centuries, biomass has been used for heating, cooking, steam generation, and power production;
solar energy has been used for heating and drying; geothermal energy has been used for hot water supplies; hydropower, for movement;
and wind energy, for pumping and irrigation. For many decades renewable energy sources have also been used to produce electricity or
other modern energy carriers
A heuristic method for determining CO2 efficiency in transportation planning
Background CO2 emissions are generally considered the most important indicator to determine the global warming effects. Their evaluation in the case of a transportation infrastructure is generally not easy and could be achieved through a separate balance
Magnetic resonance imaging findings in 46 elbows with a radial head fracture
Radial head fractures are common, and may be associated with other injuries of clinical importance. We present the results of a standard additional MRI scan for patients with a radial head fracture. PATIENTS AND METhods: 44 patients (mean age 47 years) with 46 radial head fractures underwent MRI. 17 elbows had a Mason type-I fracture, 23 a Mason type-II fracture, and 6 elbows had a Mason type-III fracture. Associated injuries were found in 35 elbows: 28 elbows had a lateral collateral ligament lesion, 18 had capitellar injury, 1 had a coronoid fracture, and 1 elbow had medial collateral ligament injury. The incidence of associated injuries with radial head fractures found with MRI was high. The clinical relevance should be investigate
Fungal GH25 muramidases : New family members with applications in animal nutrition and a crystal structure at 0.78Å resolution
Muramidases/lysozymes hydrolyse the peptidoglycan component of the bacterial cell wall. They are found in many of the glycoside hydrolase (GH) families. Family GH25 contains muramidases/lysozymes, known as CH type lysozymes, as they were initially discovered in the Chalaropsis species of fungus. The characterized enzymes from GH25 exhibit both β-1,4-N-acetyl- and β-1,4-N,6-O-diacetylmuramidase activities, cleaving the β-1,4-glycosidic bond between N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) moieties in the carbohydrate backbone of bacterial peptidoglycan. Here, a set of fungal GH25 muramidases were identified from a sequence search, cloned and expressed and screened for their ability to digest bacterial peptidoglycan, to be used in a commercial application in chicken feed. The screen identified the enzyme from Acremonium alcalophilum JCM 736 as a suitable candidate for this purpose and its relevant biochemical and biophysical and properties are described. We report the crystal structure of the A. alcalophilum enzyme at atomic, 0.78 Å resolution, together with that of its homologue from Trichobolus zukalii at 1.4 Å, and compare these with the structures of homologues. GH25 enzymes offer a new solution in animal feed applications such as for processing bacterial debris in the animal gut
Climate changes spatial planning : knowledge project plan
Uitgave in het kader van Programma Klimaat voor Ruimt
Structural and functional insights into asymmetric enzymatic dehydration of alkenols
The asymmetric dehydration of alcohols is an important process for the direct synthesis of alkenes. We report the structure and substrate specificity of the bifunctional linalool dehydratase isomerase (LinD) from the bacterium Castellaniella defragrans that catalyzes in nature the hydration of β-myrcene to linalool and the subsequent isomerization to geraniol. Enzymatic kinetic resolutions of truncated and elongated aromatic and aliphatic tertiary alcohols (C5-C15) that contain a specific signature motif demonstrate the broad substrate specificity of LinD. The three-dimensional structure of LinD from Castellaniella defragrans revealed a pentamer with active sites at the protomer interfaces. Furthermore, the structure of LinD in complex with the product geraniol provides initial mechanistic insights into this bifunctional enzyme. Site-directed mutagenesis confirmed active site amino acid residues essential for its dehydration and isomerization activity. These structural and mechanistic insights facilitate the development of hydrating catalysts, enriching the toolbox for novel bond-forming biocatalysis
Climategate: de feiten
Het waarheidsgehalte van het jongste IPCC-rapport staat zwaar onder druk. Gevolg is dat wereldwijd het draagvlak groeit voor criticasters die beweren dat klimaatverandering als gevolg van menselijk handelen een fabeltje is. Dat is het beslist niet, betogen Rik Leemans en Wim Turkensteen. Punt voor punt gaan de twee hoogleraren, beiden direct betrokken bij het IPCC, in op de gesignaleerde onjuistheden en voorzien deze van commentaar. Verplichte kost voor iedereen die zich in het klimaatdebat roert
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