Extractability and bioavailability of zinic,nickle, cadmium and copper in three Danish soils sampled 5 years after application of sewage sludge

Soils from three Danish experiments testing identical quantities of sewage sludge were sampled 5 years after the application of sludge ceased. Chemical studies on the soils involving single and sequential extractions, displaced solution measurements and plant uptake experiments in a glasshouse showed that sludge-added Zn, Ni, Cd and Cu persisted in extractable and bioavailable forms in the topsoils and that soil pH and texture influenced their chemistry and availability. The EDTA-extractabilities of native and of sludge-added Cd were similar, but native Zn, Ni and Cu were less extractable than sludge-added metals. 0.1 M-calcium chloride was the best extractant for predicting plant uptake. In some cases a chelating extractant combined with pH measurements is suitable if a single reagent is to be used for all four metals.     

The bending performance of T&G joints subjected to concentrated loads

The stiffness, considered to be the slope of the linear region of the load-displacement chart has been calculated. Linear regression lines between failure load and stiffness were sought. Relatively good correlation (R²=0.88) was found for the unjointed samples, however, less good correlation (R²=0.63) was found for the glued jointed samples and even worse correlation (R²=0.53) was found for the unglued jointed ones. Generally, the stiffness can be considered as a useful indicator for the failure load and failure mode of the particleboard samples. For increased stiffness values the boards tend to fail at higher loads and in a more brittle mode, providing a sudden vertical drop in the load/displacement curves. At values over 456 N/mm `catastrophic' failure modes (instant total failures) were observed (span size of 450 mm and thickness of the boards of 18 mm). However, at values less than 420 N/mm the failure mode was more ductile, described by `smooth' post failure curves. By gluing the joints the stiffness of the structure increases significantly. The failure load also increases but not by an amount that is statistically significant. The failure mode of glued jointed structures seems to be more ductile when compared to unglued ones. This means that after the maximum failure load has been achieved, the boards continue to sustain the load for a longer period of time up to ultimate failure occurs.

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2 =0,88), schwache für verleimte Proben (R²=0,63) und noch schw?chere für unverleimte Verbindungen (R²=0,53). Allgemein erwies sich die Steifigkeit der Spanplatten als guter Indikator für die zu erwartende Bruchlast und die Art des Bruchs. Bei erh?hter Steifigkeit erfolgte der Bruch bei h?herer Belastung, war zunehmend spr?der und zeigte als ein pl?tzlicher senkrechter Abfall in der Verformungskurve. Bei Werten oberhalb 456 N/mm erfolgte ein unmittelbares totales Versagen (Katastrophenfall). Bei Werten unterhalb 420 N/mm war der Bruchverlauf z?her mit “sanfterem” Kurvenverlauf nach dem Bruch.

     

Difference in hydrophobic and hydrophilic multilayered systems

Functional clothing, sportswear and military uniforms, are mainly made of polyester or cotton fabrics for dealing with sweat absorption and heat transfer produced by the human body. The human body typically wears two or three garments, such as innerwear, T-shirt, and jacket, thus comprising a multilayered system. Garments’ responses to heat transfer and vapor flow differ depending on whether their physical structures are hydrophobic or hydrophilic. Hence, this study analyzes differences in heat transfer and vapor flow, induced by the human body covered with multilayered garment systems, consisting of three polyester or cotton layers. In particular, it verifies three differences in the heat transfer and relative humidity, amount of relative humidity, and response time of thermal equilibrium in multilayered systems by using a new measurement system, “H&M evaluation device”. Resultant data provide precise information regarding several differences in hydrophilic and hydrophobic multilayered fabric systems.     

Semiclosed-Cell Mullite Foams: Preparation and Macro- and Micromechanical Characterization

The preparation and characterization of the properties of mullite ceramic foams suitable for diesel exhaust filtration systems are described. Two foams of different cell sizes, 32 and 61 ppi (pores per inch), were prepared from slurries by the replication process with polyurethane sponges as the templates. The microstructure and the dependence of the porosity and the mechanical properties on the preparation and resulting foam cell size and normalized density are discussed. In addition the micro- and macromechanical properties have been characterized using instrumented indentation techniques; with sharp (Berkovich) and small spherical-tipped indenters the hardness and modulus of the dense strut materials have been measured. The macroproperties have been measured with a large sapphire indenter, ∼5 mm radius using a load partial-unloading technique. The latter enables the modulus and the contact pressure versus penetration to be measured. These values are compared with traditional bulk measurements for crushing strength and elastic modulus. The results are discussed in terms of available theoretical treatments of the indentation of brittle porous materials.     

Novel macro-microporous gelatin scaffold fabricated by particulate leaching for soft tissue reconstruction with adipose-derived stem cells

The restoration of body contours as shaped by adipose tissue remains a clinical challenge specifically in patients who have experienced loss of contour due to trauma, surgical removal of tumours or congenital abnormalities. We have developed a novel macro-microporous biomaterial for use in soft tissue re-bulking and augmentation. Alginate beads provided the pore template for the construct. Incorporation, and subsequent dissolution, of the beads within a 7 % (w/v) gelatin matrix, produced a highly porous scaffold with an average pore size of 2.01 ± 0.08 mm. The ability of this scaffold to support the in vitro growth and differentiation of human adipose-derived stem cells (ADSCs) was then investigated. Histological analysis confirmed that the scaffold itself provided a suitable environment to support the growth of ADSCs on the scaffold walls. When delivered into the macropores in a fibrin hydrogel, ADSCs proliferated and filled the pores. In addition, ADSCs could readily be differentiated along the adipogenic lineage. These results therefore describe a novel scaffold that can support the proliferation and delivery of ADSCs. The scaffold is the first stage in developing a clinical alternative to current treatment methods for soft tissue reconstruction.     

Retrieval of phytoplankton size from bio-optical measurements: theory and applications

The absorption coefficient of a substance distributed as discrete particles in suspension is less than that of the same material dissolved uniformly in a medium—a phenomenon commonly referred to as the flattening effect. The decrease in the absorption coefficient owing to flattening effect depends on the concentration of the absorbing pigment inside the particle, the specific absorption coefficient of the pigment within the particle, and on the diameter of the particle, if the particles are assumed to be spherical. For phytoplankton cells in the ocean, with diameters ranging from less than 1 µm to more than 100 µm, the flattening effect is variable, and sometimes pronounced, as has been well documented in the literature. Here, we demonstrate how the in vivo absorption coefficient of phytoplankton cells per unit concentration of its major pigment, chlorophyll a, can be used to determine the average cell size of the phytoplankton population. Sensitivity analyses are carried out to evaluate the errors in the estimated diameter owing to potential errors in the model assumptions. Cell sizes computed for field samples using the model are compared qualitatively with indirect estimates of size classes derived from high performance liquid chromatography data. Also, the results are compared quantitatively against measurements of cell size in laboratory cultures. The method developed is easy-to-apply as an operational tool for in situ observations, and has the potential for application to remote sensing of ocean colour data.     

EFFICIENT NEW SYNTHESES OF POLYCYCLIC AROMATIC HYDROCARBON ORTHO-QUINONES AND THEIR 2′-DEOXYRIBONUCLEOSIDE ADDUCTS

Three mechanisms have been proposed to explain the carcinogenic activities of polycyclic aromatic hydrocarbons (PAHs). On the basis of the nature of the active metabolites involved, they may be termed: the diol epoxide mechanism, the quinone mechanism, and the radical-cation mechanism. In connection with studies to evaluate the relative importance of these pathways, we required practical methods for the syntheses of the active PAH metabolites involved. We now report efficient new synthesis of the o-quinones of benzo[a]pyrene (BPQ), 7,12-dimethylbenz[a]anthracene (DMBAQ), and benz[a]anthracene (BAQ). These quinones are convenient synthetic precursors of the related o-catechols, trans-dihydrodiols, and diol epoxides, as well as the stable adducts of the o-quinones with 2-deoxyadenosine and 2′-deoxyguanosine.     

Spatio-temporal modelling of climate-sensitive disease risk: Towards an early warning system for dengue in Brazil

This paper considers the potential for using seasonal climate forecasts in developing an early warning system for dengue fever epidemics in Brazil. In the first instance, a generalised linear model (GLM) is used to select climate and other covariates which are both readily available and prove significant in prediction of confirmed monthly dengue cases based on data collected across the whole of Brazil for the period January 2001 to December 2008 at the microregion level (typically consisting of one large city and several smaller municipalities). The covariates explored include temperature and precipitation data on a 2.5^°×2.5^° longitude-latitude grid with time lags relevant to dengue transmission, an El Niño Southern Oscillation index and other relevant socio-economic and environmental variables. A negative binomial model formulation is adopted in this model selection to allow for extra-Poisson variation (overdispersion) in the observed dengue counts caused by unknown/unobserved confounding factors and possible correlations in these effects in both time and space. Subsequently, the selected global model is refined in the context of the South East region of Brazil, where dengue predominates, by reverting to a Poisson framework and explicitly modelling the overdispersion through a combination of unstructured and spatio-temporal structured random effects. The resulting spatio-temporal hierarchical model (or GLMM—generalised linear mixed model) is implemented via a Bayesian framework using Markov Chain Monte Carlo (MCMC). Dengue predictions are found to be enhanced both spatially and temporally when using the GLMM and the Bayesian framework allows posterior predictive distributions for dengue cases to be derived, which can be useful for developing a dengue alert system. Using this model, we conclude that seasonal climate forecasts could have potential value in helping to predict dengue incidence months in advance of an epidemic in South East Brazil.