Monte Carlo calculation of the small sample reactivity effect

A monte Carlo method for the calculation of the reactivity effect of a small sample in a nuclear reactor is described. Particle histories are started within the sample. Therefore, it is not necessary to enter the sample from outside with a small probability. After leaving the sample, the histories are terminated at some distance from the sample site using pre-calculated results of the unperturbed reference system. The influence of some approximations is diminished because these pre-calculated results are used only far away from the region of interest. Some numerical results show the efficiency of the method. The method is fast and can also be used at rather small and slow computers.     

How tree shrews (Tupaia belangeri) perform in a searching task: Evidence for strategy use.

This study investigated how male tree shrews (Tupaia balngeri) performed in a searching task while in their home cages and assessed whether different food distributions affected their performance. The animals were faced with a holeboard containing 9 food sources arranged in a 3 X 3 matrix or in 3 clusters, each containing 3 sources. Animals tended to start and end the trials from preferred locations, thereafter solving the task by strategically organizing the reward collection according to a minimum-distance principle. In the cluster configuration, they visited the sources hierarchically. Food distribution did not affect the performance. Comparison with data from mice and capuchin monkeys revealed that tree shrews and capuchins solved the task in a similar strategic way, whereas mice did not. These findings attract particular attention because of the phylogenetic position of tree shrews, which are regarded as closely related to primates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rheological,microstructural and sensory characterization of low-fat and whole milk set yoghurt as influenced by inulin addition

The effect of inulin addition (0–4%) upon texture and microstructure of set yoghurt with different levels of fat (0.2%–3.5%) was investigated. A two-factor experimental design with four treatments was used for data analysis. Skimmed milk with various inulin and cream concentrations was standardized to 4% protein content, homogenized, heated to 92 °C and fermented at 42 °C until a pH of 4.6 was reached. The chemical composition, pH, consistency and microstructure properties of the yoghurts were analysed after 6 days of storage at 5 °C. The statistical analysis showed that inulin and fat significantly affected the rheological and sensory results. Higher yield stress, “firmness” and “creaminess” values were observed in yoghurt produced with higher inulin additions, whereas the pH value was not affected. A significant correlation was found between yield stress and sensory determined firmness (r = 0.91). The microstructure examined by confocal laser scanning microscopy (CLSM) was only slightly affected by the concentrations of inulin in the range studied, possibly due to weak protein interactions between the inulin and the milk protein network.     

Microbial Abundance in the Schwertmannite Formed in a Mine Water Treatment Plant

Treatment of acidic iron- and sulfate-rich mine waters in a pilot plant at the opencast lignite mining pit Nochten (Lusatia, Germany) involves microbial iron oxidation and subsequent precipitation of the iron-oxyhydroxysulfate schwertmannite. To determine if recirculation of schwertmannite can stabilize and optimize the oxidation process, cell number, viability, and diversity of the bacterial community in schwertmannite precipitated on carrier material and stored schwertmannite were analyzed. In schwertmannite on carrier material, the total cell number decreased slightly with increasing mineral depth, whereas the percentage of viable cells decreased significantly. The microbial community, investigated by fluorescence-in-situ-hybridization (FISH) and terminal restriction fragment length polymorphism (T-RFLP), revealed the presence of the iron-oxidizing bacterium “Ferrovum” sp. and relatives of Gallionella, independent of mineral depth. Analysis of the viability of microorganism in stored schwertmannite indicated an almost constant percentage of viable cells over 42 days.     

Etching of Laminates with Hydrogen Peroxide in Sulphuric Acid Solution

Three types of nuclear reaction have been applied to study chromium conversion coatings on zinc electroplate. The 1005keV resonance in the ⁵²Crlp, Y)⁵³Mn reaction has been used to determine the depth versus concentration profile of chromium in the coatings, while the ¹⁵O(d,α) ¹⁴N reaction has been used to profile oxygen content, or particle induced elastic forward scattering of protons (proton recoil) was used to determine the hydrogen profile in the samples. The results suggest that the newly introduced trivalent type treatments produce coatings containing comparable water/hydroxide contents to the establishedhexavalent type treatments.     

New statistical method for detection and quantification ofrespiratory sinus arrhythmia

A statistical method with the advantages of 1) enabling graphical representation of within-respiratory cycle heart rate variations, 2) detecting the presence of respiratory sinus arrhythmia (RSA) in a moving window, and 3) providing breath-by-breath RSA amplitude and phase obtained from the fitting of a sinusoid to the instantaneous relative heart rate is presented.     

cis-Diaminedichloroplatinum(II) Complexes Reversibly Linked into the Main Chain of Water-Soluble Polyamides

As a follow-up study to previous work involving the platination of polyamide carriers through metal chelation by side group-incorporated ethylenediamine ligands, the present investigation is concerned with the synthesis of platinum-containing polymers in which the metal-coordinating ethylenediamine segments are components of the main chain. Two chloro groups in cis geometry are attached to each Pt atom as additional ligands, complementing a square-planar cis-diaminedichloroplatinum(II) complex system. The water-soluble polymeric carriers are synthesized by Michael-type addition polymerization, interfacial polymerization, and high-temperature solution polycondensation techniques and are crudely fractionated by stepwise aqueous dialysis, ultimately in tubing with a molecular mass cutoff of 25,000. Carrier platination is brought about by treatment with tetrachloroplatinate(II) anion in aqueous solution, care being taken to exercise strict control of reaction variables and workup conditions in an effort to restrict platination to the given ligands and avoid metal aquation or hydroxylation. The platinum conjugates, with Pt contents ranging from about 11 to 23% by mass, are completely soluble in aqueous media when freshly prepared, although long-term storage at room temperature in the solid state is conducive to gradual loss of solubility. The conjugates are of interest as carcinostatic agents.     

Heterogeneous functionalizing of polysulfone membranes

In recent years efforts have been increased to work with more intelligent membranes which render more than normal filtration properties. Thus, membranes have been prepared using chemically modified polymers or have been furnished with additives in order to increase their selectivity and/or special sorbing capabilities. In this paper, methods are described how commercially available polysulfone membranes can be functionalized by chemical reactions without disintegrating their mechanical properties. For this purpose, Sulfonation, chloromethylation, aminomethylation, and lithiation reactions were applied. A broad spectrum for further conversions modified membranes is opened by these chemical reactions which allow an individual fitting of the membranes with special substitutes. The chemical reactions and the analytical procedures are also described.     

Ozonation of Cycloalkenes Dissolved in Ethanol

The ozonation of cyclooctene and cyclododecene in ethanol was studied at 278 K in a stirred reactor with a flat gas/liquid interface. The parallel reactions with ethanol in the gas and the liquid phase had to be accounted for. At high cyclooctene concentrations, ozone transfer into the liquid phase was enhanced by up to a factor of E = 325. Due to the high ozone solubility and the high enhancement factors, up to half of the mass transfer resistance was on the gas-side. The reaction rate constant k₂ is more than threefold higher for cyclooctene as compared to cyclododecene.