The Complete Analysis of Wood Polysaccharides Using HPLC

The paper describes an analytical method whereby the chemical composition of the polysaccharide fraction of woody materials, including the uronic acids and carbohydrate acid degradation products, can be completely determined. Sealed vessels, termed bombs, are used during the high temperature acid hydrolysis of the materials to retain volatile constituents that would otherwise be lost. High-Performance Liquid Chromatography (HPLC) is used for all of the analyses. The sample preparation procedures are simple and easily adopted into a routine. To demonstrate the reproducibility of the method, triplicate samples of Quaking aspen ( Populus tremuloides ) and White fir ( Abies concolor ) were analyzed. No significant peaks in the chromatograms were left unidentified.     

Conceptual Design for SuperCDMS SNOLAB

Beyond the present dark matter direct detection experiment at the Soudan underground laboratory, the SuperCDMS Collaboration is engaged in R&D activities for a 100-kg scale germanium dark matter experiment nominally sited at SNOLAB (2070 m overburden of rock). The expected sensitivity after 3 years of running is 3×10^?46?cm² for the spin-independent cross section, an order of magnitude improvement over present exclusion limits for WIMP masses ～80?GeV/c². At this depth, and appropriate design of shielding and cryostat, neutron backgrounds will be negligible. The baseline design is an expanded version of CDMS II with Ge substrates (100×33?mm discs) instrumented with the iZIP phonon sensor layout to achieve the electron surface-event rejection power required.     

A sub-50meV spectrometer and energy filter for use in combination with 200kV monochromated (S)TEMs

A high-energy resolution post-column spectrometer for the purpose of electron energy loss spectroscopy (EELS) and energy-filtered TEM in combination with a monochromated (S)TEM is presented. The prism aberrations were corrected up to fourth order using multipole elements improving the electron optical energy resolution and increasing the acceptance of the spectrometer for a combination of object area and collection angles. Electronics supplying the prism, drift tube, high-tension reference and critical lenses have been newly designed such that, in combination with the new electron optics, a sub-50 meV energy resolution has been realized, a 10-fold improvement over past post-column spectrometer designs. The first system has been installed on a 200 kV monochromated TEM at the Delft University of Technology. Total system energy resolution of sub-100 meV has been demonstrated. For a 1s exposure the resolution degraded to 110 meV as a result of noise. No further degradation in energy resolution was measured for exposures up to 1 min at 120 kV. Spectral resolution measurements, performed on the pi* peak of the BN K-edge, demonstrated a 350 meV (FWHM) peak width at 200 kV. This measure is predominantly determined by the natural line width of the BN K-edge.     

Relevance of hair and spines of the European hedgehog (Erinaceus europaeus) as biomonitoring tissues for arsenic and metals in relation to blood

Hair has been proven to be suitable for non-destructive and non-invasive exposure assessments in human and mammal populations. A previous study with European hedgehog (Erinaceus europaeus) showed that, for some metals, hair and spine metal concentrations were positively correlated to levels in liver, kidney and muscle. Although blood has been studied in a wide variety of species, the relationship between hair and blood metal concentrations has yet to be quantified in many mammalian species. Tissue concentrations from hedgehogs residing in a park with known metal pollution were compared with those from a reference park and correlations between contaminant levels in hair and blood, and spines and blood were studied. Moreover, the relative distribution of arsenic and metals in hair, spines and blood was determined. Elevated concentrations were found in hedgehogs residing in the polluted site for As (8.2 μg/g, 6.3 μg/g, 3.6 μg/ml), Cd (0.48 μg/g, 0.17 μg/g, 0.02 μg/ml) and Pb (7.6 μg/g, 7.3 μg/g, 54 μg/ml), in hair, spines and blood respectively. Positive correlations were identified for exposure levels between hair and blood as well as between spines and blood for three elements (As, Cd, and Pb), whereas a negative correlation was found between Cr concentrations in spines and blood. In conclusion, hair and spines can be used to monitor blood concentrations of some metals, although more data are needed on uptake from the food chain and on the incorporation dynamics of these contaminants.     

Integration and decentralization: the evolution of Dutch regional land policy

The implementation of planning objectives in the public interest depends on the land laws and land policies of a state. Public stakeholders are not only enabled or constrained in their actions by these laws and policies, they also (re)formulate these laws and policies to support their actions. The objective of this paper is to understand how different stakeholders in spatial development processes influence land policy dynamics (both the (re)formulation and the implementation of policies) and vice versa. The paper explores the changes in land policies in the Netherlands, in particular how changes have enabled the regional planning level. The Policy Arrangement Approach is used to analyse the strategic behaviour of agencies and their use of structure in spatial development processes. The findings show that the arrangement rapidly changed from the 1980s onwards, due to changes in the underlying political discourses and the effectuation of these discourses via regulation and instruments. With objectives of decentralization and integration, the national government has enabled the regional planning level to become more active in spatial development processes. Although the provinces were enabled by new laws and policies, this did not significantly change their role within the Dutch planning system.     

Nanomaterials for environmental studies: Classification, reference material issues, and strategies for physico-chemical characterisation

NanoImpactNet is a European Commission Framework Programme 7 (FP7) funded project that provides a forum for the discussion of current opinions on nanomaterials in relation to human and environmental issues. In September 2008, in Zurich, a NanoImpactNet environmental workshop focused on three key questions:

1.

What properties should be characterised for nanomaterials used in environmental and ecotoxicology studies?

2.

What reference materials should be developed for use in environmental and ecotoxicological studies?

3.

Is it possible to group different nanomaterials into categories for consideration in environmental studies?

Such questions have been, at least partially, addressed by other projects/workshops especially in relation to human health effects. Such projects provide a useful basis on which this workshop was based, but in this particular case these questions were reformulated in order to focus specifically on environmental studies. The workshop participants, through a series of discussion and reflection sessions, generated the conclusions listed below.The physicochemical characterisation information identified as important for environmental studies included measures of aggregation/agglomeration/dispersability, size, dissolution (solubility), surface area, surface charge, surface chemistry/composition, with the assumption that chemical composition would already be known.There is a need to have test materials for ecotoxicology, and several substances are potentially useful, including TiO₂ nanoparticles, polystyrene beads labelled with fluorescent dyes, and silver nanoparticles. Some of these test materials could then be developed into certified reference materials over time.No clear consensus was reached regarding the classification of nanomaterials into categories to aid environmental studies, except that a chemistry-based classification system was a reasonable starting point, with some modifications. It was suggested, that additional work may be required to derive criteria that can be used to generate such categories, that would also include aspects of the material structure and physical behaviour.     

Monte Carlo Simulation of Massive Absorbers for Cryogenic Calorimeters

There is a growing interest in cryogenic calorimeters with macroscopic absorbers for applications such as dark matter direct detection and rare event search experiments. The physics of energy transport in calorimeters with absorber masses exceeding several grams is made complex by the anisotropic nature of the absorber crystals as well as the changing mean free paths as phonons decay to progressively lower energies. We present a Monte Carlo model capable of simulating anisotropic phonon transport in cryogenic crystals. We have initiated the validation process and discuss the level of agreement between our simulation and experimental results reported in the literature, focusing on heat pulse propagation in germanium. The simulation framework is implemented using Geant4, a toolkit originally developed for high-energy physics Monte Carlo simulations. Geant4 has also been used for nuclear and accelerator physics, and applications in medical and space sciences. We believe that our current work may open up new avenues for applications in material science and condensed matter physics.     

Study of the dead layer in germanium for the CDMS detectors

We present new measurements on a Cryogenic Dark Matter Search (CDMS) detector with electron, neutron, and gamma sources. The measurements have been performed to investigate the dead layer of one of the CDMS Z-dependent Ionization Phonon germanium detectors. The dead layer has been studied at both charge electrodes and at different electric field intensities. We also present a method to remove the dependence of athermal phonon measurements on event position.