Graphene-Semiconductor Composites as Visible Light-Induced Photocatalyst

Graphene-based composites produced by the incorporation of graphene into suitable semiconductors doped with various metals enable to induce the unique properties of the graphene, such as extended light absorption range, charge separation, and so high dye adsorption capacity. Therefore, graphene-based composites can provide to enhance the overall photocatalytic performance of the base semiconductor under the visible-light, and to open up new pathways to high-performance photocatalyst for the future applications. This chapter of the book focuses on the structural and optical properties of the graphene-semiconductor-based composite structure. Furthermore, final photocatalytic properties of the graphene-based composites can be controlled by applying different synthesis routes. Common synthesis methods of the graphene-semiconductor composites such as sol-gel, solution mixing, in situ growth, hydrothermal growth, and solvothermal method are discussed on the resultant visible-light photocatalytic property of the these composites. At the same time, doping of the graphene-semiconductor material with metal ions also allows an improvement of the visible light-induced photocatalytic activity. Therefore, studies related with the effect of the dopant agent on the visible light photocatalytic activity are also reviewed in this chapter

The role of insulin/IGF-1 signaling in the longevity of model invertebrates, C. elegans and D. melanogaster.

Insulin/insulin-like growth factor (IGF)-1 signaling (IIS) pathway regulates aging in many organisms, ranging from simple invertebrates to mammals, including humans. Many seminal discoveries regarding the roles of IIS in aging and longevity have been made by using the roundworm Caenorhabditis elegans and the fruit fly Drosophila melanogaster. In this review, we describe the mechanisms by which various IIS components regulate aging in C. elegans and D. melanogaster. We also cover systemic and tissue-specific effects of the IIS components on the regulation of lifespan. We further discuss IIS-mediated physiological processes other than aging and their effects on human disease models focusing on C. elegans studies. As both C. elegans and D. melanogaster have been essential for key findings regarding the effects of IIS on organismal aging in general, these invertebrate models will continue to serve as workhorses to help our understanding of mammalian aging.1126Ysciescopuskc

SYNTHESIS OF Ag-DOPED ZnO NANO FIBERS USING ELECTROSPINNING METHOD AND THEIR PHOTOCATALYTIC ACTIVITIES

Silver (Ag) doped zinc oxide (ZnO) nanofibers with 1 at% and 3 at% Ag content were prepared using the electrospinning technique and their structural, morphological and photocatalytic  properties were investigated. Pure ZnO nanofibers were also prepared with the same procedure for structure and property related comparison purposes. The photocatalytic activity of the Ag doped ZnO nanofibers were determined as a function of Ag content by exploring the degradation behavior of methylene blue under UV light irradiation. It was found that photocatalytic ability of fibers was improved with Ag addition and higher Ag incorporation resulted better methylene blue degradation rate. For pure ZnO fibers, the remaining dye was 48% of its initial amount after 270 min of UV irradiation time. For the same irridation time, 60% and 67% decomposition ratios of the dye molecules were achieved with the fibers containing 1 at.% Ag and 3 at.% Ag, respectively. The origin of the improvement of photocatalytic activity in Ag doped ZnO nanofibers was attributed to the substitutional incorporation of Ag ions into Zn sites within the ZnO crystal. The substitutional incorporation has been proved with the positional shift of the XRD diffraction lines

Value of Caffeic Acid Phenethyl Ester Pretreatment in Experimental Sepsis Model in Rats

Background and Aim. The aim of this study was to determine the actions of caffeic acid phenethyl ester (CAPE) on the changes of endothelin-1 (ET-1) level, tumor necrosis factor- (TNF-) alpha, and oxidative stress parameters such as superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels in experimental sepsis model in rats. Materials and Methods. Twenty-four rats were randomly divided into three experimental groups: sham (group 1), sepsis (group 2), and sepsis + CAPE (group 3), n = 8 each. CAPE was administered (10 µmol/kg) intraperitoneally to group 3 before sepsis induction. Serum ET-1, serum TNF-alpha, tissue SOD activity, and tissue MDA levels were measured in all groups. Results. Pretreatment with CAPE decreased ET-1, TNF-alpha, and MDA levels in sepsis induced rats. Additionally SOD activities were higher in rats pretreated with CAPE after sepsis induction. Conclusion. Our results demonstrate that CAPE may have a beneficial effect on ET and TNF-alpha levels and oxidative stress parameters induced by sepsis in experimental rat models. Therefore treatment with CAPE can be used to avoid devastating effects of sepsis

Food-derived sensory cues modulate longevity via distinct neuroendocrine insulin-like peptides

Environmental fluctuations influence organismal aging by affecting various regulatory systems. One such system involves sensory neurons, which affect life span in many species. However, how sensory neurons coordinate organismal aging in response to changes in environmental signals remains elusive. Here, we found that a subset of sensory neurons shortens Caenorhabditis elegans' life span by differentially regulating the expression of a specific insulin-like peptide (ILP), INS-6. Notably, treatment with food-derived cues or optogenetic activation of sensory neurons significantly increases ins-6 expression and decreases life span. INS-6 in turn relays the longevity signals to nonneuronal tissues by decreasing the activity of the transcription factor DAF-16/FOXO. Together, our study delineates a mechanism through which environmental sensory cues regulate aging rates by modulating the activities of specific sensory neurons and ILPs.1186Ysciescopu

Study on a daf-18/PTEN allele that uncouples distinct phenotypes in daf-2/Insulin/IGF-1 receptor mutant C. elegans

MasterInsulin/IGF-1 signaling is one of the well-described and evolutionarily conserved longevity-mediating pathway. The Caenorhabditis elegans daf-2 is a key regulator of lifespan, larval development and resistance to bacterial pathogens. Although many research has been conducted to date, whether the regulation of pleiotropic effects such as development and immunity can be uncoupled at a certain point in IIS pathway has not been addressed yet. In this study, a mutant animal with complete suppression of dauer state which is hibernation-like stage of diapause, and relatively reduced pathogen resistance in daf-2(e1370) mutant background, hereby named as sdli (Suppressor-of-Dauer-but-Less-Immunity), was generated through EMS mutagenesis. Its various physiologic characteristics have been identified. A new mutation on daf-18 gene was reported as the causative of sdli phenotype in daf-2(e1370) mutant animals, whose genotype is daf-2(e1370); daf-18(yh1). It was found out that C105Y change in DAF-18 is the EMS-induced change leading to sdli phenotype. Various life history traits of daf-2(e1370); daf-18(yh1) were examined including lifespan, brood size, and oxidative stress resistance were also examined. Importantly, mutant animal also preserved increased lifespan up to certain level compared to well-known null mutant daf-2(e1370); daf-18(nr2037). This study is important since it is an example of how a specific daf-18 mutation can uncouple certain pleiotropic phenotypes of daf-2(e1370) mutants

Specific PTEN mutations uncouple development and immunity phenotypes conferred by reduced insulin/IGF-1 signaling in C. elegans

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Effect of precipitation temperature and organic additives on size and morphology of ZnO nanoparticles

Low temperature (25 degrees C-80 degrees C) synthesis of zinc oxide (ZnO) nanoparticles (<20 nm) at short synthesis periods (similar to 30 min) was achieved by precipitation. The precipitation system was formed using zinc acetate dihydrate as zinc source, ethylene glycol (EG) as solvent and polyvinyl pyrrolidone (PVP) as chelating agent. The size of spherical ZnO nanoparticles was manipulated by the choice of precipitation temperature (13.0 +/- 1.9 nm at 25 degrees C and 9.0 +/- 1.3 nm at 80 degrees C), which essentially changes the nature of adsorption events between ZnO crystals and organic molecules. The particle size can also be regulated by the amount of chelating agent as a result of further enhancement in adsorption between ZnO crystals and organic additives. The spherical ZnO nanoparticles were agglomerated into triangular form when different solvent was used - by substituting water for EG, which has different adsorption ability. Accordingly, formation and growth mechanisms controlling the size and morphology of ZnO nanoparticles have been proposed