Changes in optical properties caused by UV-irradiation of aquatic humic substances from the amazon river basin: seasonal variability evaluation

Aquatic humic substances (AHS) isolated from two characteristic seasons of the Negro river, winter and summer corresponding to floody and dry periods, were structurally characterized by 13C nuclear magnetic ressonance. Subsequently, AHS aqueous solutions were irradiated with a polychromatic lamp (290-475 nm) and monitored by its total organic carbon (TOC) content, ultraviolet-visible (UV-vis) absorbance, fluorescence, and Fourier transformed infrared spectroscopy (FTIR). As a result, a photobleaching up to 80% after irradiation of 48 h was observed. Conformational rearrangements and formation of low molecular complexity structures were formed during the irradiation, as deduced from the pH decrement and the fluorescence shifting to lower wavelengths. Additionally a significant mineralization with the formation of CO2, CO, and inorganic carbon compounds was registered, as assumed by TOC losses of up to 70%. The differences in photodegradation between samples expressed by photobleaching efficiency were enhanced in the summer sample and related to its elevated aromatic content. Aromatic structures are assumed to have high autosensitization capacity effects mediated by the free radical generation from quinone and phenolic moieties.     

Effect of processing for saponin removal on fungal contamination of quinoa seeds (Chenopodium quinoa Willd.)

Incidence of fungal contamination of quinoa seeds from three locations (Salar de Uyuni, Bolivia; Salta and Tucumán provinces, Argentina) was analyzed in samples with and without treatment to remove saponins (wet method). In processed samples, the percentage of infection was reduced. Distribution of the different fungal genera was not homogeneous in the three locations (p<0.05), although Penicillium and Aspergillus were the most prevalent contaminants, regardless the geographic origin of the samples. Other genera, such as Eurotium, Fusarium, Phoma, Ulocladium, Mucor and Rhizopus were less frequently isolated. Absidia, Alternaria, Cladosporium, Dreschlera, Epicoccum and Monascus were sporadically encountered. Significant differences (p<0.05) in the distribution of fungal genera in samples with and without saponins from each location were observed. In all cases, processing caused a decrease of Aspergillus incidence, while increased the proportion of Penicillium, Eurotium, Mucor and Rhizopus indicating that these genera were part of the internal mycota. A. flavus and A. niger were the dominating species of genus Aspergillus. A similar pattern of prevalent Penicillium species was observed in samples with and without saponins, since P. aurantiogriseum, P.chrysogenum, P. citrinum and P. crustosum were always present in high number, although their relative density was variable according to the geographic origin of samples. Mycotoxin-producing ability of most representative species was also determined. Toxigenic strains of A. flavus (aflatoxins and cyclopiazonic acid), A. parasiticus (aflatoxins), P. citrinum (citrinin) and P. griseofulvum (cyclopiazonic acid) were found. None of the A. niger isolates was ochratoxin A producer. The above mentioned mycotoxins were not detected in the samples analyzed.     

Assessment of Mineralogical,Textural, and Water Chemistry Changes During Long-Distance Tailings-Slurry Transport

An exploratory study demonstrated that subtle changes in solids and process water were caused by long-distance turbulent transport of tailings from the concentrator to the impoundment of a Cu (Mo) porphyry copper deposit. Slurry water chemical analysis was complemented by modelling potential phase precipitation or dissolution and speciation of dissolved metals. It was found that transport did not affect major insoluble mineral phases. However, the degrees of liberation of several phyllosilicates, as determined by automated mineralogy, were reduced close to the impoundment, which points to separation of clay particles from tectosilicate surfaces by the turbulence; this also was observed by SEM examination of micro-aggregate specimens. Reduction of maximum particle sizes, increased N2 monolayer adsorption, and resultant specific surface areas indicate that transport modified the micro-aggregates. Major element water chemistry is controlled by the presence of soluble mineral phases, such as gypsum, and reagents, such as lime, in the flotation process. Changes in the dissolved concentrations of some elements could potentially affect tailings deportment in the impoundment. Increased concentrations of Al may affect the clay settling behaviour, while Mo and As levels will require treatment prior to the discharge of water from the tailings impoundment. This study demonstrated that systematic scrutiny of tailings slurries leaving the concentrator and before entering the impoundment can be potentially useful, though care will have to be exercised to replicate sample handling and analytical conditions, during any long-term monitoring.     

Tracking Hidden Binding Pockets Along the Molecular Recognition Path of l-Trp to Indoleamine 2,3-Dioxygenase 1

Indoleamine 2,3-dioxygenase 1 (IDO1) catalyzes the oxidative cleavage of l -Tryptophan (l -Trp) to yield N-formyl-kynurenine in the first and rate limiting step of the kynurenine pathway. Bioactive metabolites, involved in the regulation of important immunological responses and neurological processes, are then produced by downstream enzymes along the pathway. Inhibitors of IDO1 are being designed and developed as therapeutic agents for immuno-oncology. In this work, we investigated the molecular recognition path of l -Trp to IDO1, integrating biophysical methods with supervised molecular dynamics (suMD) and mutagenesis experiments. Results allowed disclosing for the first time high and low dissociation constants of l -Trp to IDO1, and the presence of a metastable interaction site located at the upper part of a channel whose borders are defined by the EF-loop and the C-terminal part of the JK-loop. Collectively, our results provide new clues for the design of next-generation IDO1 ligands.     

Isomere Monoensäuren in Pflanzenölen

Isomeric Monoenoic Acids in Vegetable Oils In the scope of systematic studies the fatty acids of oils from seed and fruits of 38 plants are investigated for presence of isomeric monoenoic acids with 16, 18 and 20 C-atoms. All analyzed oils contain between 2 and 4 hexadecenoic, octadecenoic and icosenoic acids with different position of the double bound. Vaccenic acid, the cis-11-octadecenoic acid, is always found in low quantities. Its share depends within certain limits on the content of the oils of cis-9-hexadecenoic acid, the so-called palmitoleic acid. Petroselinic acid, cis-6-octadecenoic acid, is found in apiaceae oils and also in the seed oil of some other plant families. Besides, 14 of the investigated oils contain low quantities of ω5-monoenoic acids.     

Einfluß der Segmentstruktur und der Vernetzung auf den Glasübergang Tg. Möglichkeiten der Vorausberechnung von Tg über die Kohäsionsenergie Ecoh

Linear polymers, particularly polyesters, and crosslinked epoxide systems were studied to determine the relationship between glass transition, T_g, and cohesive energy, E_coh, which was calculated from incremental values as described by Fedors. In the case of thermoplastics having no side chains and in the absence of pronounced intermolecular interactions, it was found that standardization of E_coh with reference to the number of structural elements capable of rather independent motions leads to a linear relationship between T_g, and E_coh from which T_g, can be predicted. Without modifying our equation to suit the polymer, the influence of substituents and side chains can as yet only be assessed when they form a small part of the total segment. In the case of crosslinked epoxide systems, addition of the contribution made by crosslinking to the value of T_g, for the uncured polymer calculated from E_coh results in a shift to higher T_g, values. In linear aliphatic polyamides and other polymers with analogous structure the formation of hydrogen bonds leads to an increase in T_g, comparable to the effect of chemical crosslinking. Reinforcing fillers also act as multifunctional crosslinks between the macromolecules and increase T_g. Just as E_coh can be used to calculate T_g, experimentally readily ascertainable T_g values can be used to calculate E_coh. This approach provides information on material properties like flexural strength at the yield point and torsional adhesive strength as well as on the effect of reinforcing fillers.     

鲁尔：一部区域规划的简史

本文根据鲁尔区的产业发展总结了这一地区在20世纪的区域规划。自1871年统一为德意志帝国后,鲁尔区是德国最重要的经济地区之一,直至第一次世界大战(1914-1918)结束这里经历了经济发展的第一个阶段,二战(1939-1945)后又经历了第二个经济增长阶段。在这一时期形成的基础产业煤炭和钢铁生产在1970年代逐渐失去了发展动力,而此时在各地区都出现了新技术发展和新经济增长地区的形成。为了扭转衰败局面,鲁尔区以新规划思想为基础制定了新规划,利用了现有的最初是为工业地区组织的景观结构,并将其重新构造为后工业区域的景观系统。     

Fitting in and feeling fine: Conformity and coping motives as mediators of the relationship between social anxiety and problematic drinking.

The present research was conducted to clarify the relationships among social anxiety, alcohol consumption, alcohol-related problems, and negative-reinforcement drinking motives among college students. Heavy drinking students (N = 316, 53.80% female) completed self-report measures of social anxiety, alcohol consumption, alcohol-related problems, and drinking motives. Findings indicated that students higher in social anxiety consumed less alcohol but experienced more negative consequences. Moreover, the relationship between social anxiety and negative consequences was mediated by coping and conformity drinking motives in addition to alcohol consumption. In the context of social anxiety, the current research demonstrates the importance of examining problematic drinking as distinct constructs: alcohol consumption and negative consequences. Findings are also discussed in terms of implications for interventions with socially anxious students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)