In vitro kinetic analysis of carbohydrate and aromatic amino acid metabolism of different members of the human colon

The carbohydrate and aromatic amino acid metabolism of several species related to the human colon was investigated into more detail. Therefore, in vitro fermentations were performed, with different carbohydrate sources, during which several aromatic amino acids were added to the fermentation medium. Shifts in end-product formation in response to the available nutrients were observed for all strains tested. The major part of amino acid degradation occurred after depletion of the carbohydrates. Moreover, it was shown that Bifidobacterium strains are capable of degrading aromatic amino acids in the absence of carbohydrates. The excretion of certain intermediates of the aromatic amino acid metabolism was observed for a strain of Clostridium clostridioforme, after which they were metabolized again during a later stage of fermentation. This implies that cross-feeding on degradation products of aromatic amino acids, albeit within the same species, can occur in the human colon.     

A review of the current status of small-scale seawater reverse osmosis desalination

The current status of small-scale desalination (produced water capacity 100 m³/day or less) is reviewed to provide an overview of the market segment. The use of energy-recovery devices in this market segment is also reviewed. We find that the Middle East accounts for the largest market share worldwide at present, and reverse osmosis is overwhelmingly dominant among the desalination technologies adopted. Implementation of energy-recovery devices at small scale is rare, which leads to relatively high energy consumption for small-scale seawater reverse osmosis desalination systems.     

DFT-Study on Antioxydant of 3-Alkyl-4-P henylacetylam i no-1H-1,2,4-Triazol-5-O nes and Its Derivatives

In this article, we have performed B3LYP/6-31＋G（d） calculations of geometrical and reaction enthalpies of antioxidant mechanisms for ADPHT 1-4 （3-alkyl-4-phenylacetylamino-lH-1,2,4-triazol-5-ones） and its derivatives： HAT （hydrogen atom transfer）, SET-PT （single electron transfer-proton transfer） and SPLET （sequential proton-loss electron transfer） were investigated in gas and solution-phases. Solvent contribution to enthalpies was computed employing integral equation formalism IEF-PCM （integral equation formalism method） method. It turned out that the lowest BDEs （bond dissociation energies） is obtained for C-H bonds due to captodative effect in various media. Results indicate that HAT mechanism represents the most anticipated process in gas-phase from thermodynamic point of view. But, the SPLET represents the thermodynamically preferred reaction pathway in solvents （2-propanol, acetonitrile, DMF （N,N-dimethylformamide） and water）. The authors showed that bond dissociation energies, IP （ionization potential） and PA （proton affinity） are sufficient to evaluate the thermodynamically preferred mechanism.     

Hanseniaspora opuntiae, Saccharomyces cerevisiae, Lactobacillus fermentum, and Acetobacter pasteurianus predominate during well-performed Malaysian cocoa bean box fermentations,underlining the importance of these microbial species for a successful cocoa bean fermentation process

Two spontaneous Malaysian cocoa bean box fermentations (one farm, two plantation plots) were investigated. Physical parameters, microbial community dynamics, yeast and bacterial species diversity [mainly lactic acid bacteria (LAB) and acetic acid bacteria (AAB)], and metabolite kinetics were monitored, and chocolates were produced from the respective fermented dry cocoa beans. Similar microbial growth and metabolite profiles were obtained for the two fermentations. Low concentrations of citric acid were found in the fresh pulp, revealing low acidity of the raw material. The main end-products of the catabolism of the pulp substrates glucose, fructose, and citric acid by yeasts, LAB, and AAB were ethanol, lactic acid, acetic acid, and/or mannitol. Hanseniaspora opuntiae, Lactobacillus fermentum, and Acetobacter pasteurianus were the prevalent species of the two fermentations. Saccharomyces cerevisiae, Lactobacillus plantarum, Lactobacillus pentosus, and Acetobacter ghanensis were also found during the mid-phase of the fermentation processes. Leuconostoc pseudomesenteroides and Acetobacter senegalensis were among the prevailing species during the initial phase of the fermentations. Tatumella saanichensis and Enterobacter sp. were present in the beginning of the fermentations and they could be responsible for the degradation of citric acid and/or the production of gluconic acid and lactic acid, respectively. The presence of facultative heterofermentative LAB during the fermentations caused a high production of lactic acid. Finally, as these fermentations were carried out with high-quality raw material and were characterised by a restricted microbial species diversity, resulting in successfully fermented dry cocoa beans and good chocolates produced thereof, it is likely that the prevailing species H. opuntiae, S. cerevisiae, Lb. fermentum, and A. pasteurianus were responsible for it.     

Growth and energy generation by Enterococcus faecium FAIR-E 198 during citrate metabolism

Citrate metabolism by Enterococcus faecium FAIR-E 198, isolated from Greek Feta cheese, was studied in various growth media containing citrate either in the presence of glucose, or as the sole carbon source, both under aerobic and anaerobic conditions. In de Man-Rogosa-Sharpe (MRS) broth with increasing citrate concentrations, cometabolism of citrate and glucose took place. Glucose was stoichiometrically converted into lactate, while citrate into acetate. Glucose consumption and biomass yield were enhanced with increasing initial citrate concentrations, even though maximum specific growth rate was not. When citrate was used as the sole carbon source in increasing initial concentrations, the main end product was acetate. Small amounts of lactate, formate, ethanol, and acetoin were also produced. In all cases, no significant differences were observed between aerobic and anaerobic conditions. However, when citrate was used as sole carbon source, formate production was favored in the absence of oxygen. The present work shows that E. faecium is able to utilize citrate in synthetic media, either in the presence of glucose or as the sole carbon source, resulting in energy production and the formation of aroma compounds.     

Exposure of several Belgian consumer groups to pesticide residues through fresh fruit and vegetable consumption

The output of a pesticide surveillance program (detection frequency and number of exceeding measures) can lead to unnecessary concern among consumers since they lack information concerning the actual exposure. In this study, the exposure to pesticide residues through fruit and vegetable consumption is evaluated based on the 2008 surveillance data of the Belgian Federal Agency for the Safety of the Food Chain (FASFC).Results (deterministic and probabilistic approach) demonstrate that the chronic exposure of the adult population (>15 years) is generally under control, even at high or frequent consumption of fruit and vegetables. For most of the pesticide residues studied, the exposure is one hundred times lower than the ‘acceptable daily intake’ or ADI. With regard to children (2–5 years) who consume regularly or large amounts of fruit and vegetables, there are however, indications that for some pesticides the ADI can be exceeded. Nevertheless, due to the large uncertainty in these calculations, a more detailed study is required for this vulnerable group of consumers. In addition, it was demonstrated that washing and peeling of fruit and vegetables result in an exposure that is probably five to six times lower.     

Adaptation for river basins: connecting policy goals to the water resources system.

This paper focuses on a methodology called 'generic adaptation methodology for river basins' (AMR) that provides guidance to water managers seeking: (1) potential adaptation measures to climate change and climate variability, (2) measuring impacts, and (3) evaluating adaptations. The methodology uses basic elements addressed in existing adaptation research and is designed for a participatory setting involving various stakeholders. In AMR, the water resources system is seen as an economic asset that provides 'goods and services' for both humans and ecosystems. The innovative aspect of AMR is that it distinguishes impacts to water management objectives and impacts to the physical state of water resources in a river basin in a relatively simple iterative approach. Both impact types are quantified using indicators. The framework and results are demonstrated for a case study in the Walawe basin (Sri Lanka). It is explained that actually implementing adaptations in policy making can be difficult in trans-boundary river basins as each riparian country has its own policy objectives and hence ways of dealing with adaptation.     

Cluster-grouping: from subgroup discovery to clustering

We introduce the problem of cluster-grouping and show that it can be considered a subtask in several important data mining tasks, such as subgroup discovery, mining correlated patterns, clustering and classification. The algorithm CG for solving cluster-grouping problems is then introduced, and it is incorporated as a component in several existing and novel algorithms for tackling subgroup discovery, clustering and classification. The resulting systems are empirically compared to state-of-the-art systems such as CN2, CBA, Ripper, Autoclass and CobWeb. The results indicate that the CG algorithm can be useful as a generic local pattern mining component in a wide variety of data mining and machine learning algorithms.     

Instability during cohesive zone growth

Tensile microcracking of quasi-brittle materials is studied by means of micromechanics, based on (i) an elasto-damaging cohesive zone model accounting for cohesive softening and (ii) a dilute distribution of non-interacting microcracks of uniform orientation and size. Considering virgin microcracks (initially without cohesive zones), macroscopic tensile load increase results in growth of cohesive zones ahead of stationary (non-propagating) cracks and, subsequently, in crack propagation which, notably, will be encountered before the cohesive zones are fully developed i.e. onset of instable cohesive zone growth will be encountered at a load level (i) at which tractions are still transmitted across the inner edges of the cohesive zones and (ii) at which the separation at the inner edges of the cohesive zones is smaller than its critical value. Focusing on onset of instable cohesive zone growth, the chosen approach allows for accessing quantities characterizing the stability limit (e.g., the intensity of the macroscopic loading and the opening at the inner edges of the cohesive zones), without raising the need for non-linear Finite Element analyses. It is shown that the tensile macrostrength of materials containing virgin microcracks is larger than the one related to cracks with already initially fully developed cohesive zones, and related strength differences are quantified for a wide class of cohesive softening behavior. The proposed model is validated by comparing model predictions with an exact solution (available for the special case of constant cohesive tractions) and with results from reliable Finite Element analyses. The paper will be of interest for engineers involved in testing and/or in modeling of quasi-brittle media including cementitious materials and rock.