Evaluation of process variables in bench-scale bio-oxidation of the Olympias concentrate

Abstract: A statistically designed set of eight bio-oxidation tests on the Olympias concentrate was conducted in bench-scale equipment to evaluate the effects of important variables on pyrite/arsenopyrite oxidation and gold extraction. The variables studied were total retention time, feed solid concentration and particle size. High degrees of arsenopyrite oxidation were observed in all tests, as the arsenopyrite oxidation was very fast and therefore not dependent on the variables within the studied range. Statistical analysis of the experimental data reveals that the pyrite oxidation and gold extraction are dependent mainly on the retention time and to a lesser extent on the particle size. The feed solid concentration had a small influence only on the gold extraction. Regressed equations of the experimental data can be used to predict proper operating conditions.     

Purification of an Enzyme with Lysophospholipase Activity from Rat Intestinal Mucosa by Hydrophobic Chromatography

A method based on hydrophobic chromatography is described for the purification of a lysophospholipase from the mucosa of rat small intestine. Under the conditions used, one single chromatographic run on phenyl-Sepharose CL-4B yielded a 582-fold purification with a 79% overall recovery of enzyme activity. A sub-unit molecular weight of 56,000 was deduced from sodium dodecyl sulphate gel electrophoresis; its isoelectric point is 5.6.     

Increased levels of soluble CD40L in African tick bite fever: possible involvement of TLRs in the pathogenic interaction between Rickettsia africae, endothelial cells, and platelets

The pathophysiological hallmark of spotted fever group rickettsioses comprises infection of endothelial cells with subsequent infiltration of inflammatory cells. Based on its ability to promote inflammation and endothelial cell activation, we investigated the role of CD40L in African tick bite fever (ATBF), caused by Rickettsia africae, using different experimental approaches. Several significant findings were revealed. 1) Patients with ATBF (n = 15) had increased serum levels of soluble CD40 ligand (sCD40L), which decreased during follow-up. 2) These enhanced sCD40L levels seem to reflect both direct and indirect (through endothelial cell activation involving CX3CL1-related mechanisms) effects of R. africae on platelets. 3) In combination with sCD40L, R. africae promoted a procoagulant state in endothelial cells by up-regulating tissue factor and down-regulating thrombomodulin expression. 4) Although the R. africae-mediated activation of platelets involved TLR2, the combined procoagulant effects of R. africae and sCD40L on endothelial cells involved TLR4. 5) Doxycycline counteracted the combined procoagulant effects of R. africae and sCD40L on endothelial cells. Our findings suggest an inflammatory interaction between platelets and endothelial cells in ATBF, involving TLR-related mechanisms. This interaction, which includes additive effects between sCD40L and R. africae, may contribute to endothelial inflammation and hypercoagulation in this disorder.     

Effect of a Medicinal Agaricus blazei Murill-Based Mushroom Extract,AndoSan?, on Symptoms,Fatigue and Quality of Life in Patients with Ulcerative Colitis in a Randomized Single-Blinded Placebo Controlled Study

Background

Ingestion of AndoSan^™, based on the mushroom Agaricus blazei Murill, has previously been shown to exhibit anti-inflammatory effects because of reduction of pro-inflammatory cytokines in healthy individuals and patients with ulcerative colitis. In this randomized single-blinded placebo controlled study we examined whether intake of AndoSan^™ also resulted in clinical effects.

Methods and Findings

50 patients with symptomatic ulcerative colitis were block-randomized and blinded for oral daily intake of AndoSan^™ or placebo for the 21 days’ experimental period. The patients reported scores for symptoms, fatigue and health related quality of life (HRQoL) at days 0, 14 and 21. Fecal calprotectin and general blood parameters were also analyzed. In the AndoSan^™ group (n = 24) symptoms improved from baseline (day 0) to days 14 and 21, with respective mean scores (95% CI) of 5.88 (4.92–6.83), 4.71 (3.90–5.52) (p = 0.002) and 4.50 (3.70–5.30) (p = 0.001). Corresponding improved mean scores (±SD) for total fatigue were 16.6 (5.59), 14.1 (4.50) (p = 0.001) and 15.1 (4.09) (p = 0.023). These scores in the placebo group (n = 26) were not improved. When comparing the two study groups using mixed model statistics, we found significant better scores for the AndoSan^™-patients. HRQoL for dimensions bodily pain, vitality, social functioning and mental health improved in the AndoSan^™ group. There were no alterations in general blood samples and fecal calprotectin.

Conclusions

Beneficiary effects on symptoms, fatigue and HRQoL from AndoSan^™ consumption were demonstrated in this per-protocol study, supporting its use as a supplement to conventional medication for patients with mild to moderate symptoms from ulcerative colitis. The patients did not report any harms or unintended effects of AndoSan^™ in this study.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01496053","term_id":"NCT01496053"}}NCT01496053     

Gone…but not away—addressing the problem of long-term impacts from landfills in LCA

Background, aim and scope  Land filling of materials with content of toxic metals or highly persistent organic compounds has posed a problem for life cycle assessment (LCA) practitioners for many years. The slow release from the landfill entails a dilution in time, which is dramatic compared to other emissions occurring in the life cycle, and with its focus on the emitted mass, LCA is poorly equipped to handle this difference. As a consequence, the long-term emissions from landfills occurring over thousands of years are often disregarded, which is unacceptable to many stakeholders considering the quantities of toxic substances that can be present. On the other hand, inclusion of all future emissions (over thousands of years) in the inventories potentially dominates all other impacts from the product system. The paper aims to present a pragmatic approach to address this dilemma. Materials and methods  Two new impact categories are introduced representing the stored ecotoxicity and stored human toxicity of the contaminants remaining in the landfill after a ‘foreseeable’ time period of 100 years. The impact scores are calculated using the normal characterisation factors for the ecotoxicity and human toxicity impact categories, and they represent the toxicity potentials of what remains in the landfill after 100 years (hence the term ‘stored’ (eco)toxicity). Normalisation references are developed for the stored toxicity categories based on Danish figures to support comparison with indicator scores for the conventional environmental impact categories. In contrast to the scores for the conventional impact categories, it is uncertain to what extent the stored toxicity scores represent emissions, which will occur at all. Guidance is given on how to reflect this uncertainty in the weighting and interpretation of the scores. Results and discussion  In landfills and road constructions used to deposit residuals from incinerators, less than 1% of the content of metals is leached within the first 100 years. The stored toxicity scores are therefore much higher than the conventional impact scores that represent the actual emissions. Several examples are given illustrating the use and potential significance of the stored toxicity categories. Conclusions and perspectives  The methodology to calculate stored human and ecotoxicity is a simple and pragmatic approach to address LCA’s problem of treating the slow long-term emissions at very low concentrations appropriately. The problem resides in the inventory analysis and the impact assessment, and the methodology circumvents the problem by converting it into a weighting and interpretation issue accommodating the value-based discussion of how to weight potential effects in the far future. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Lower–Middle Ordovician carbon and oxygen isotope chemostratigraphy at Hällekis,Sweden: implications for regional to global correlation and palaeoenvironmental development

A high‐resolution chemostratigraphical (coupled δ¹³C_carb and δ¹⁸O_carb) study of the topmost Floian through the middle Darriwilian (Ordovician) succession at the Hällekis quarry, Kinnekulle, southern Sweden, shows relatively steady isotopic values with overall minor changes, although some notable short‐ and long‐term shifts are discernible. A pronounced positive shift in δ¹³C in the uppermost part of the study succession is identified as the Middle Darriwilian Isotopic Carbon Excursion (MDICE), representing the only named global isotopic excursion in the data set. Regional and global comparisons suggest that few details in the different carbon and oxygen isotope curves can be confidently correlated, but longer‐term patterns appear quite consistent. Trends in the isotope data are in agreement with palaeogeographical reconstructions. Differences in stratigraphical patterns of both carbon and oxygen isotopes between localities suggest strong secular development at several spatiotemporal scales; any global signal involving relatively minor isotopic shifts is often masked/subdued by local and regional overprinting and care should be taken not to overinterpret data sets. Collectively, the data suggest rising sea levels and cooling climates through the studied time interval, but detailed interpretations remain problematic.     

OXIDIZED AND REDUCED GLUTATHIONE IN THE RAT BRAIN UNDER NORMOXIC AND HYPOXIC CONDITIONS

In order to test the proposition that hypoxia leads to a change in the concentration ratio of reduced (GSH) and oxidized (GSSG) glutathione in the brain, enzymatic, fluorometric assays were worked out for measuring GSH and GSSG. In lightly anaesthetized and immobilized rats. GSH concentrations in the cerebral cortex and the cerebellum were close to 2 μmol.g^-1 while a slightly lower concentration (approx 1.4μmol.g^-1) was found in the brain stem. In order to avoid artefactual oxidation of GSH during sample preparation for GSSG determination the tissue was extracted with trichloroacetic acid, following alkylation of SH groups with N-ethylmaleimide. With these precautions GSSG concentrations were approx 0.7% of the corresponding GSH concentrations. However. the results indicated that the true GSSG concentrations may be even lower. During hypoxia there was neither a decrease in GSH nor an increase in GSSG concentrations in cortical tissue or cisternal CSF.     

The oxygen isotope composition of planktonic foraminifera from the Cariaco Basin,Venezuela: Seasonal and interannual variations

Material collected during a three-year sediment trapping experiment in the Cariaco Basin, Venezuela (January 1997 to December 1999) is used to examine both temporal and inter-species variability in the oxygen isotope composition of planktonic foraminifera. Specifically, this study compares the oxygen isotope composition of six species of planktonic foraminifera (Globigerinoides ruber (pink), Globigerina bulloides, Neogloboquadrina dutertrei, Orbulina universa, Globorotalia menardii and Globorotalia crassaformis) with the climatology and hydrography of the region, and evaluates the application of each species for use in paleoceanographic reconstructions. The isotope results are consistent with known depth habitats for all six species. The lowest δ¹⁸O values (− 1 to − 2‰) were measured on G. ruber (pink) and G. bulloides, two species that live in the surface mixed layer. Values for deeper-dwelling species such as N. dutertrei, G. menardii and G. crassaformis are higher, predominantly ranging from 0 to − 0.5‰. Temperature estimates derived using species-specific paleotemperature equations indicate that G. ruber (pink) accurately estimates sea surface temperatures (SSTs) throughout the year, while G. bulloides temperature estimates are similar to measured surface temperatures only during the upwelling season (January–April). For the remainder of the year, the δ¹⁸O-derived temperatures for G. bulloides typically are lower than the measured SST. Although the maximum flux of all species occurs during upwelling, the flux-weighted annual mean isotopic composition of the six species indicates that only G. bulloides is biased towards this season. Therefore, we conclude that the sediment δ¹⁸O record of G. ruber (pink) is most suitable for estimating past values of mean annual SST, while G. bulloides provides information on conditions during spring upwelling. The depth of calcification of N. dutertrei varies seasonally in response to changes in the depths of the thermocline and chlorophyll maximum. As a result, the δ¹⁸O difference between G. ruber (pink) and N. dutertrei provides an estimate of the annual surface to thermocline temperature gradient in the basin.     

Nematode control in 'green' ruminant production systems

Collectively, nematode parasites of domestic ruminants continue to pose the greatest disease problem in grazing livestock systems worldwide, despite the powerful and extensive chemotherapeutic arsenal available for their control. The widespread development of anthelmintic resistance, particularly in nematode parasites of small ruminants, and the trend towards non-chemical (ecological, organic, green) farming of livestock has provided an impetus for the research and development of alternative parasite control methods. This article provides a brief overview of the non-chemotherapeutic options for parasite control and how they might play a role either in organic farming or in other low-input farming systems.     

The oxygen isotope composition of planktonic foraminifera from the Guaymas Basin,Gulf of California: Seasonal,annual, and interspecies variability

Sediment trap samples collected over a seven-year period (February 1991–October 1997) from Guaymas Basin in the Gulf of California were used to study the oxygen isotope composition of five species of planktonic foraminifera, Globigerinoides ruber (white), Globigerina bulloides, Neogloboquadrina dutertrei, Pulleniatina obliquiloculata, and Globorotalia menardii. The δ¹⁸O data were analyzed for temporal and interspecies variability and were compared to local hydrography to evaluate the use of each species in reconstructing past oceanographic applications. The two surface dwelling species, G. ruber and G. bulloides displayed the lowest δ¹⁸O values (～ 0.0 to ? 5.0‰), while δ¹⁸O values for the thermocline dwelling N. dutertrei, P. obliquiloculata, and G. menardii were higher (～ 0.0 to ? 2.0‰). The δ¹⁸O of G. ruber most accurately records measured sea surface temperatures (SSTs) throughout the year. G. bulloides δ¹⁸O tracks SSTs during the winter–spring upwelling period but for the remainder of the year records slightly colder, subsurface temperatures. The difference between the δ¹⁸O of the surface dwelling species, G. ruber and G. bulloides, and that of the thermocline dwelling species, N. dutertrei, P. obliquiloculata, and G. menardii, was used to estimate the surface to thermocline temperature gradient. During the winter these δ¹⁸O differences are small (～ 0.50‰) reflecting a well-mixed water column. These interspecies δ¹⁸O differences increase during the summer (～ 1.90‰) in response to the strong thermal stratification that exists at this time of year.