Relevance of peat-draining rivers for the riverine input of dissolved iron into the ocean

Peat bogs have the ability to produce strong chelate ligands (humic and fulvic acids) which enhance the weathering rates of iron-silicate minerals and greatly increase the solubility of the essential trace metal iron in river water. Fluvial networks link peat bogs with the ocean, and thus terrestrial-derived fulvic-iron complexes fuel the ocean's biological productivity and biological carbon pump, but understanding this role is constrained by inconsistent observations regarding the behaviour of riverine iron in the estuarine mixing zone, where precipitation reactions remove iron from the water column. We applied a characterization of the colloidal iron carriers in peatland-draining rivers in North Scotland, using field-flow fractionation (FFF), in combination with end-member mixing experiments of river water sampled near the river mouth and coastal seawater using a ⁵⁹Fe radiotracer method. According to our results, the investigated river contributed “truly dissolved” Fe concentrations of about 3300 nmol L^− 1 to the ocean which is nearly two orders of magnitude higher than the dissolved iron contribution of the “average world” river (∼ 40 nmol L^− 1). Thus we conclude that peatland-draining rivers are important sources of dissolved iron to the ocean margins. We propose highly electrostatic and sterical stabilized iron-organic matter complexes in the size range of < 2 kDa to be responsible for iron transport across the estuarine mixing zone.     

Scalar transport in a milli-scale metal foam reactor

We present an investigation on species mass transfer in a milli-scale plug flow reactor using metal foams to enhance the mixing process. In the current design the reactor consists of a pipe with an inner diameter of 7 mm and metal foam inserts with different pore sizes of 20, 30 and 45 ppi. Simultaneous PIV and LIF measurements were performed in orthogonal planes normal to the radial and axial direction downstream of a foam element of 50 mm length. The investigated Reynolds numbers range from 600 to 7600 defined with the empty tube diameter and the bulk velocity. We discuss the influence of the pore sizes on the scalar mixing efficiency and compare the results to the reference empty tube case. A strongly intermittent flow caused by the metal foam was observed over the whole range of Reynolds numbers. The increased radial velocities lead to an enhanced mixing performance. Coefficients of Variation in the order of 0.1 were achieved.     

Investigations on the oxalic acid content of honey from oxalic acid treated and untreated bee colonies

Varroa destructor, an ectoparasitic mite, is one of the major pests of honeybees in many parts of the world. In order to keep bee colonies alive and productive, effective biological, biotechnical, or acaricidal control measures are necessary. Oxalic acid is one substance under discussion to replace synthetic acaricides (e.g. pyrethroids, organophosphates) to minimize the risk of residues in bee products. The application of oxalic acid based solutions (Bienenwohl or a self-prepared oxalic acid solution with sugar) to control Varroa destructor resulted in no relevant changes in the oxalic acid content of honey produced the following year, compared with honey samples from untreated colonies from the same location. The range of oxalic acid content in honey was 5–68 mg/kg in oxalic acid treated and 5–65 mg/kg in untreated colonies. The oxalic acid content of the honey was positively correlated with its electrical conductivity and thus with its original nectar or honeydew source.     

Multivariate process trajectories for molecular description of MF thermal curing and correlation with hydrolytic stability

During curing of thermosetting resins the technologically relevant properties of binders and coatings develop. However, curing is difficult to monitor due to the multitude of chemical and physical processes taking place. Precise prediction of specific technological properties based on molecular properties is very difficult. In this study, the potential of principal component analysis (PCA) and principal component regression (PCR) in the analysis of Fourier transform infrared (FTIR) spectra is demonstrated using the example of melamine-formaldehyde (MF) resin curing in solid state. FTIR/PCA-based reaction trajectories are used to visualize the influence of temperature on isothermal cure. An FTIR/PCR model for predicting the hydrolysis resistance of cured MF resin from their spectral fingerprints is presented which illustrates the advantages of FTIR/PCR compared to the combination differential scanning calorimetry/isoconversional kinetic analysis. The presented methodology is transferable to the curing reactions of any thermosetting resin and can be applied to model other technologically relevant final properties as well.     

Bedeutung des Speichersystems Lohsa II für die wasserhaushaltliche Sanierung im Spreegebiet

Within the framework of the mining remidiation the residual holes of the former brown coal opencast mines “Lohsa”, “Dreiweibern” and “Burghammer” will be connected with each other in order to form the retaining system “Lohsa II”. Including the neighbouring residual hole “Bärwalde” they will provide a storage capacity of more than 90 millions m ³ (118.421 millions cu yards). Considering the water economy the project is expected to be completely ready for operation in the year 2005. Up to 13 m ³ /s (16.9 cu yards per second) of water are to be supplied during dry spells. This will sustain the draining function of the river Spree which has been damaged by lignite mining. At the same time the ecological requirements of the biosphere reserve “Spreewald” and the demands of the conurbation Berlin – concerning its water supply and water storage – will be fulfilled     

Micro RNA-124a Regulates Lipolysis via Adipose Triglyceride Lipase and Comparative Gene Identification 58

Lipolysis is the biochemical pathway responsible for the catabolism of cellular triacylglycerol (TG). Lipolytic TG breakdown is a central metabolic process leading to the generation of free fatty acids (FA) and glycerol, thereby regulating lipid, as well as energy homeostasis. The precise tuning of lipolysis is imperative to prevent lipotoxicity, obesity, diabetes and other related metabolic disorders. Here, we present our finding that miR-124a attenuates RNA and protein expression of the major TG hydrolase, adipose triglyceride lipase (ATGL/PNPLA2) and its co-activator comparative gene identification 58 (CGI-58/ABHD5). Ectopic expression of miR-124a in adipocytes leads to reduced lipolysis and increased cellular TG accumulation. This phenotype, however, can be rescued by overexpression of truncated Atgl lacking its 3''UTR, which harbors the identified miR-124a target site. In addition, we observe a strong negative correlation between miR-124a and Atgl expression in various murine tissues. Moreover, miR-124a regulates the expression of Atgl and Cgi-58 in murine white adipose tissue during fasting as well as the expression of Atgl in murine liver, during fasting and re-feeding. Together, these results point to an instrumental role of miR-124a in the regulation of TG catabolism. Therefore, we suggest that miR-124a may be involved in the regulation of several cellular and organismal metabolic parameters, including lipid storage and plasma FA concentration.     

Functioning and life context among spouses of remitted and nonremitted depressed patients.

The functioning and life context of spouses of depressed patients were examined at the patients' treatment intake and again after 1 year. Three groups of spouses were defined according to their depressed partner's recovery status at follow-up: remitted (n?=?39), partially remitted (n?=?39), or nonremitted (n?=?40). These spouse groups were compared with each other and with spouses of demographically matched community control participants (n?=?157). At both assessments, the remitted and control spouses were comparable in functioning, stressors, and coping, but the remitted spouses had more social and family problems than control spouses. In contrast, nonremitted spouses had significantly more problems than control spouses on most indices, both at intake and at follow-up. There was no evidence that adaptation of remitted spouses improved or that adaptation of nonremitted spouses deteriorated. Spouse adaptation was typically unrelated to changes in the depression of the depressed partner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thickness dependence of the electrical resistivity of epitaxially grown silver films

Silver films were deposited onto (111)-oriented single-crystal silicon substrates under different deposition conditions. The thickness dependence of their electrical resistivity was analysed in terms of the Fuchs-Sondheimer theory. The scattering parameter p was found to vary from +0.8 to -0.8. The results are correlated with film structure. The negative p values are traced back to the predominant contribution of grain boundary scattering in the case of polycrystalline films.     

Prognose der Sorptionskinetik organischer Schadstoffe in heterogenem Aquifermaterial

A model for the simulation of kinetic sorption processes in heterogeneous aquifer material is presented. Sorption kinetics is responsible for the long persistence of many organic contaminants in the subsurface. Therefore, reliable model predictions of these processes are of major importance concerning, for instance, the design of efficient remediation strategies. The modeling approach presented here recognizes sorption kinetics as retarded diffusion within the intra-particle pore space and, in particular, takes into account the sedimentological and petrographical composition of the aquifer material. This is in accordance with results from laboratory experiments quantifying sorption/desorption processes. For solving the model equations a finite-difference scheme is applied which incorporates several features proven to be relevant in practical model applications (mass balance, flexible choice of boundary conditions, easy handling). The simulation results shown here focus on the impact of aquifer heterogeneity (lithological composition, grain size distribution) on sorption and desorption kinetics of organic contaminants. Furthermore, this approach can be straightforwardly coupled to existing software for simulating multi-dimensional solute transport.