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Nine M.J.,Gyeongsang National University | Munkhbayar B.,Gyeongsang National University | Rahman M.S.,Hajee Mohammad Danesh Science and Technology University | Chung H.,Gyeongsang National University | Jeong H.,Gyeongsang National University
Materials Chemistry and Physics | Year: 2013

The article reports a simple, economical and highly productive synthesis process of cuprous oxide (Cu2O) and copper/cuprous oxide (Cu/Cu 2O) nanoparticles with an average size of below 30 nm. A hydrolysis of copper (Cu) particles (200 nm or even microsize) employing low energy ball milling in aqueous circumstance results a controlled synthesis of Cu 2O and cermets of Cu/Cu2O nanoparticles. Ground particles are found both in nanobar and spherical shape with cluster nano-clouds into aqueous solution. X-ray diffraction patterns of the sample powder confirm Cu2O nanoparticles and Cu/Cu2O cermets synthesized by complete and incomplete oxidation of Cu particles, respectively. The process is accomplished at room temperature in presence of de-ionized (DI) water and controlled by changing milling period and ball sizes. Enhanced thermal conductivity of Cu2O-water and Cu/Cu2O-water nanofluids are recorded and compared with non-ground Cu-water nanofluids. © 2013 Elsevier B.V. All rights reserved.

Ahmed M.,Chonnam National University | Ahmed M.,Hajee Mohammad Danesh Science and Technology University | Akter M.S.,Chonnam National University | Lee J.-C.,Dongshin University | Eun J.-B.,Chonnam National University
LWT - Food Science and Technology | Year: 2010

Purple-fleshed sweet potato flour could be used to enhance the colour, flavour and nutrients in food products. Thus, the investigation was to produce encapsulated flours from purple-fleshed sweet potato by spray drying using combinations of various levels of ascorbic acid (5 g kg-1 and 10 g kg-1) and maltodextrin (30 g kg-1 and 100 g kg-1) and to evaluate their effects on bioactive components, physicochemical and morphological properties. Encapsulated flours had higher total phenolic content, antioxidant capacity and water solubility index than non-encapsulated flour. There were no significant differences in anthocyanin content between encapsulated and non-encapsulated flours. However, water absorption index and flavonoids content of encapsulated flours depended on concentrations of ascorbic acid and maltodextrin. In addition, the high concentrations of ascorbic acid and maltodextrin encapsulated flours had higher glass transition temperature as compared to that of lower concentrations. In respect to morphology, the particles of encapsulated flours with high concentration of ascorbic acid and maltodextrin were more aggregated than those encapsulated with lower concentrations. Therefore, flours encapsulated with 10 g kg-1 ascorbic acid and 30 g kg-1 maltodextrin could be used to enhance the antioxidant activities of functional food ingredients. © 2010 Elsevier Ltd.

Mehbub M.F.,Flinders University | Mehbub M.F.,Hajee Mohammad Danesh Science and Technology University | Lei J.,Flinders University | Franco C.,Flinders University | Zhang W.,Flinders University
Marine Drugs | Year: 2014

Marine sponges belonging to the phylum Porifera (Metazoa), evolutionarily the oldest animals are the single best source of marine natural products. The present review presents a comprehensive overview of the source, taxonomy, country of origin or geographical position, chemical class, and biological activity of sponge-derived new natural products discovered between 2001 and 2010. The data has been analyzed with a view to gaining an outlook on the future trends and opportunities in the search for new compounds and their sources from marine sponges. © 2014 by the authors.

El Taj H.F.,Andong National University | El Taj H.F.,Hajee Mohammad Danesh Science and Technology University | Jung C.,Andong National University
Experimental and Applied Acarology | Year: 2012

The developmental rate and reproductive biology of Neoseiulus californicus, a generalist predator on spider mites and small insects, was investigated in the laboratory at five constant temperatures: 15, 20, 25, 30, and 34°C. The European red mite, Panonychus ulmi, an important pest in Korean apple orchards, was used as prey. Mean developmental time and adult longevity were inversely related to temperature from 15 to 30°C. Lifetime fecundity was greatest at 25°C, whereas daily fecundity was highest at 30°C. The sex ratio (female to male) was highest (0.77) at 25°C and lowest (0.67) at 34°C. Survivorship during immature development varied from 74.3 to 92.9%, with the lowest rate at 34°C. Life table parameters were analyzed and pseudo-replicates for the generation time (t G), the intrinsic rate of natural increase (r m), finite rate of increase (λ), net reproductive rate (R 0), and doubling time (t D) were generated using the Jackknife method. Generation time (t G) was lowest (10.7 days) at 34°C, R 0 was highest (49.2) at 25°C, and both r m (0.29) and λ (1.34) were highest at 30°C. In conclusion, the development and adult life-history traits obtained for N. californicus fed on P. ulmi indicated significant potential for biological control. © 2012 Springer Science+Business Media B.V.

Siddique S.,University of Bonn | Matera C.,University of Bonn | Radakovic Z.S.,University of Bonn | Hasan M.S.,University of Bonn | And 6 more authors.
Science Signaling | Year: 2014

Plants and animals produce reactive oxygen species (ROS) in response to infection. In plants, ROS not only activate defense responses and promote cell death to limit the spread of pathogens but also restrict the amount of cell death in response to pathogen recognition. Plants also use hormones, such as salicylic acid, tomediate immune responses to infection. However, there are long-lasting biotrophic plant-pathogen interactions, such as the interaction between parasitic nematodes and plant roots during which defense responses are suppressed and root cells are reorganized to specific nurse cell systems. In plants, ROS are primarily generated by plasma membrane-localized NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidases, and loss of NADPH oxidase activity compromises immune responses and cell death. We found that infection of Arabidopsis thaliana by the parasitic nematode Heterodera schachtii activated the NADPH oxidases RbohD and RbohF to produce ROS, which was necessary to restrict infected plant cell death and promote nurse cell formation. RbohD- and RbohF-deficient plants exhibited larger regions of cell death in response to nematode infection, and nurse cell formation was greatly reduced. Genetic disruption of SID2, which is required for salicylic acid accumulation and immune activation in nematode-infected plants, led to the increased size of nematodes in RbohD- and RbohF-deficient plants, but did not decrease plant cell death. Thus, by stimulating NADPH oxidase-generated ROS, parasitic nematodes fine-tune the pattern of plant cell death during the destructive root invasion and may antagonize salicylic acid-induced defense responses during biotrophic life stages.

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