Antioxidant, antimicrobial, and anticancer activity of 3 Umbilicaria species

Abstract: The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activity of the acetone extracts of the lichens Umbilicaria crustulosa, U. cylindrica, and U. polyphylla. Antioxidant activity was evaluated by 5 separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds, and determination of total flavonoid content. Of the lichens tested, U. polyphylla had largest free radical scavenging activity (72.79% inhibition at a concentration of 1 mg/mL), which was similar as standard antioxidants in the same concentration. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was extract of U. polyphylla with minimum inhibitory concentration values ranging from 1.56 to 12.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All extracts were found to be strong anticancer activity toward both cell lines with IC₅₀ values ranging from 28.45 to 97.82 μg/mL. The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggests that lichens may be used as possible natural antioxidant, antimicrobial, and anticancer agents.     

Liquid–solid mass transfer in a three-phase stationary catalytic basket reactor

Measurements of the liquid–solid mass transfer coefficient k_S were performed in a three-phase multiple impeller and stationary catalytic basket reactor, called a Robinson–Mahoney reactor. Local coefficients were determined using naphtol particle dissolution in water and n-heptane with or without gas flow. Experiments have shown that local coefficients k_{S loc} depend on the particle position in the basket, agitation speed, and liquid properties. A correlation linking k_S to liquid velocity was established in a reactor simulating hydrodynamics in a piece of catalytic basket. Liquid velocity values were validated using a particle image velocimetry technique in a Robinson–Mahoney reactor, using water. © 2005 American Institute of Chemical Engineers AIChE J, 2005     

A new set of features for a bimodal system based on on-line signature and speech

In this work, a new set of features is presented for a biometric system based on speech and on-line signature. The feature vector is nonhomogeneous and it comprises using TESPAR DZ coefficients, wavelet energy coefficients and also some additional features resulted from the time domain analysis in the case of speech. A feature selection procedure is then applied to reduce the feature vector dimension. A modified symbols alphabet for the TESPAR DZ method is presented. Experimental results were reported using the SVC2004 database for signature and our own bimodal database BimDB10 (for on-line signature and speech). A feature level fusion strategy was adapted in order to achieve our goals. The results show that the fusion of biometric features brings improvement to the system performance.     

Comparison of intelligent systems in detecting a child’s mathematical gift

This paper compares the efficiency of two intelligent methods: expert systems and neural networks, in detecting children’s mathematical gift at the fourth grade of elementary school. The input space for the expert system and the neural network model consisted of 60 variables describing five basic components of a child’s mathematical gift identified in previous research. The expert system estimated a child’s gift based on heuristically defined logic rules, while the scientifically confirmed psychological evaluation of gift based on Raven’s standard progressive matrices was used at the output of neural network models. Three neural network algorithms were tested on a Croatian dataset. The results show that both the expert system and the neural network recognize more pupils as mathematically gifted than teachers do. The expert system produces the highest average hit rate, although the highest accuracy in classifying gifted children is obtained by the radial basis neural network algorithm, which also yields lower type II error. Due to the ability of expert systems to explain the result, it can be suggested that both the expert system and the neural network model have potential to serve as effective intelligent decision support tools in detecting mathematical gift in early stage, therefore enabling its further development.     

10大电源管理半导体供应商面临小型同业的竞争压力日增

据iSuppli公司报告,由于增长放缓、价格压力沉重和来自小型同业的竞争加剧,2007年最大的10家电源管理半导体供应商多数表现逊于总体市场.     

Quantification of the thaumatin-like kiwi allergen by a monoclonal antibody-based ELISA

Thaumatin-like proteins (TLPs) have been established as a new family of fruit and pollen allergens. The aim of this study was to develop a two-site ELISA for the quantification of the thaumatin-like kiwi allergen (Act d 2) in kiwifruit extracts and kiwifruit-containing food products. Genomic DNA (gDNA) of Act d 2 was amplified and the deduced amino acid sequence was determined to obtain a primary structure. Act d 2 purified from kiwifruit extract by HPLC was identified by Edman degradation and MS. Balb/c mice were immunized with Act d 2 for the production of mAbs by hybridoma technology. The optimized ELISA measured Act d 2 concentrations ranging from 0.2 to 9.0 ng/mL, with intra- and interassay coefficients of variation of 3.65 and 10.44%, respectively. The developed ELISA is a useful method for the quantification of the thaumatin-like kiwi allergen in kiwifruit extracts as well as the allergen level in kiwifruit-containing food products. It may be a helpful analytical tool for the evaluation of the stability (integrity) of fruit allergen extracts for in vitro diagnosis.     

Investigation of unusual inactivity of industrial platinum-rhodium catalyst gauze

The aim of this work was to obtain information about the causes of unusual lack of activation of fresh, unused, 90% platinum-10% rhodium catalyst gauze that was detected after the activation process in an industrial ammonia oxidation plant. To reach the usual efficiency, it was necessary to regenerate the catalyst immediately after the activation procedure by using an acid bath. To avoid future unexpected shutdowns in the ammonia oxidation plant, the possible sources of impurities accumulated on the catalyst surface were investigated by an analysis of the experimental results and technological processes. The absence of accumulation on the unused catalyst surface eliminates the possibility of contamination during the preparation, while the composition of the impurities indicates that it cannot result from the reactor construction material. In mixed feedstock, detectable amounts of the poisons mentioned were not detected either after filtration or before the reactor. All these considerations imply that the time when the catalyst contamination occurred must have been before the contact with the gas mixture. From data obtained, it is hypothesized that the origin of this substance is from the polluted air in the industrial area where the ammonia oxidation plant is located and that the accumulation probably took place during the preparation of the catalyst pad.     

An attributional analysis of the development of excuse giving in aggressive and nonaggressive African American boys.

This study examined the effects of age and aggressive status on children's understanding and use of excuses. Younger (3rd–5th grade) and older (6th–8th grade) aggressive and nonaggressive African American boys were first instructed to imagine that they failed to fulfill a social obligation. The cause of the transgression was presented as controllable (e.g., choosing to do something else), and children indicated whether they would reveal that cause or make up an excuse. Next, 4 causes of the same transgression were manipulated to be either controllable or uncontrollable. Children inferred that they would be held more responsible for controllable causes of social misconduct, that these causes would elicit more anger, and that they would be more likely to withhold these causes (i.e., make up an excuse). The linkages between perceived responsibility, anticipated anger, and excuse giving were stronger among older than younger boys and among nonaggressive than aggressive boys. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is the digestive gland of Mytilus galloprovincialis a tissue of choice for estimating cadmium exposure by means of metallothioneins?

A study performed over 12 months with caged mussels Mytilus galloprovincialis in the coastal marine zone, which is under urban pressure, reveals a temporal variation of digestive gland mass, which causes "biological dilution" of cytosolic metallothionein (MT) and trace metal (Cd, Cu, Zn, Fe, Mn) concentrations. The dilution effect was corrected by expressing the cytosolic MT and metal concentrations as the tissue content. Consequently, the changes of the average digestive gland mass coincide with the changes of MT and trace metal contents. From February to June, MT contents are nearly twice and trace metal contents nearly three times higher than those of the other months. The period of increased average digestive gland mass, of MT and trace metal contents probably overlaps with the sexual maturation of mussels (gametogenesis) and enhanced food availability. Since natural factors contribute more to the MT content than the sublethal levels of Cd, the digestive gland of M. galloprovincialis is not considered as a tissue of choice for estimating Cd exposure by means of MTs.     

Development of whey-based beverages

This paper considers beverages consisting of whey, fruit components (orange, pear, peach, and apple), citric acid and sucrose. It also offers their optimal composition. The dry matter of the fruit component, the pH of the beverage and its sucrose content were independent variables. Blends were prepared in accordance with the factorial design. After pasteurization, they were exposed to a sensor analysis so that the following characteristics were estimated: flavour, odour, colour, sediment, appearance and total quality (sum of the previous factors). By applying the regression analysis method, a mathematical model of each characteristic was derived. None of the characteristic functions had an extreme, so the maxima lay at the boundaries of the independent variables (6% of dry matter and 4% or 2% of sucrose ). Only the pH changed within a narrow range. The statistical method has shown that the quality of blends with orange and pear mostly depends on the sucrose content, while the quality of blends with peach and apple depends on the dry matter of the fruit. Interaction of dry matter and sucrose is most significant for the blend with pear, while the balance between sucrose and pH strongly depends on the quality of all the other products. The peach–whey beverage containing 6% of dry matter and 2% of sucrose as well as having pH 3.6 proved to be the best.