Microwave-assisted synthesis of water-dispersed CdTe/CdSe core/shell type II quantum dots

A facile synthesis of mercaptanacid-capped CdTe/CdSe (core/shell) type II quantum dots in aqueous solution by means of a microwave-assisted approach is reported. The results of X-ray diffraction and high-resolution transmission electron microscopy revealed that the as-prepared CdTe/CdSe quantum dots had a core/shell structure with high crystallinity. The core/shell quantum dots exhibit tunable fluorescence emissions by controlling the thickness of the CdSe shell. The photoluminescent properties were dramatically improved through UV-illuminated treatment, and the time-resolved fluorescence spectra showed that there is a gradual increase of decay lifetime with the thickness of CdSe shell

Self-Cleaning Glass of Photocatalytic Anatase TiO2@Carbon Nanotubes Thin Film by Polymer-Assisted Approach

Due to the good photocatalytic activity, the TiO2@CNTs thin film is highly desirable to apply to the self-cleaning glass for green intelligent building. Here, the TiO2@CNTs thin film has been successfully achieved by polymer-assisted approach of an aqueous chemical solution method. The polymer, polyethylenimine, aims to combine the Ti4+ with CNTs for film formation of TiO2@CNTs. The resultant thin film was uniform, highly transparent, and super-hydrophilic. Owing to fast electron transport and effectively hindering electron-hole recombination, the TiO2@CNTs thin film has nearly twofold photocatalytic performance than pure TiO2. The TiO2@CNTs thin films show a good application for self-cleaning glasses

Interspecies interactions and potential Influenza A virus risk in small swine farms in Peru

<p>Abstract</p> <p>Background</p> <p>The recent avian influenza epidemic in Asia and the H1N1 pandemic demonstrated that influenza A viruses pose a threat to global public health. The animal origins of the viruses confirmed the potential for interspecies transmission. Swine are hypothesized to be prime "mixing vessels" due to the dual receptivity of their trachea to human and avian strains. Additionally, avian and human influenza viruses have previously been isolated in swine. Therefore, understanding interspecies contact on smallholder swine farms and its potential role in the transmission of pathogens such as influenza virus is very important.</p> <p>Methods</p> <p>This qualitative study aimed to determine swine-associated interspecies contacts in two coastal areas of Peru. Direct observations were conducted at both small-scale confined and low-investment swine farms (n = 36) and in open areas where swine freely range during the day (n = 4). Interviews were also conducted with key stakeholders in swine farming.</p> <p>Results</p> <p>In both locations, the intermingling of swine and domestic birds was common. An unexpected contact with avian species was that swine were fed poultry mortality in 6/20 of the farms in Chancay. Human-swine contacts were common, with a higher frequency on the confined farms. Mixed farming of swine with chickens or ducks was observed in 36% of all farms. Human-avian interactions were less frequent overall. Use of adequate biosecurity and hygiene practices by farmers was suboptimal at both locations.</p> <p>Conclusions</p> <p>Close human-animal interaction, frequent interspecies contacts and suboptimal biosecurity and hygiene practices pose significant risks of interspecies influenza virus transmission. Farmers in small-scale swine production systems constitute a high-risk population and need to be recognized as key in preventing interspecies pathogen transfer. A two-pronged prevention approach, which offers educational activities for swine farmers about sound hygiene and biosecurity practices and guidelines and education for poultry farmers about alternative approaches for processing poultry mortality, is recommended. Virological and serological surveillance for influenza viruses will also be critical for these human and animal populations.</p

Global transcriptional response to mammalian temperature provides new insight into Francisella tularensis pathogenesis

<p>Abstract</p> <p>Background</p> <p>After infecting a mammalian host, the facultative intracellular bacterium, <it>Francisella tularensis</it>, encounters an elevated environmental temperature. We hypothesized that this temperature change may regulate genes essential for infection.</p> <p>Results</p> <p>Microarray analysis of <it>F. tularensis </it>LVS shifted from 26°C (environmental) to 37°C (mammalian) showed ~11% of this bacterium's genes were differentially-regulated. Importantly, 40% of the protein-coding genes that were induced at 37°C have been previously implicated in virulence or intracellular growth of <it>Francisella </it>in other studies, associating the bacterial response to this temperature shift with pathogenesis. Forty-four percent of the genes induced at 37°C encode proteins of unknown function, suggesting novel <it>Francisella </it>virulence traits are regulated by mammalian temperature. To explore this possibility, we generated two mutants of loci induced at 37°C [FTL_1581 and FTL_1664 (<it>deoB</it>)]. The FTL_1581 mutant was attenuated in a chicken embryo infection model, which was likely attributable to a defect in survival within macrophages. FTL_1581 encodes a novel hypothetical protein that we suggest naming <it>t</it>emperature-<it>i</it>nduced, <it>v</it>irulence-associated locus <it>A</it>, <it>tivA</it>. Interestingly, the <it>deoB </it>mutant showed diminished entry into mammalian cells compared to wild-type LVS, including primary human macrophages and dendritic cells, the macrophage-like RAW 264.7 line, and non-phagocytic HEK-293 cells. This is the first study identifying a <it>Francisella </it>gene that contributes to uptake into both phagocytic and non-phagocytic host cells.</p> <p>Conclusion</p> <p>Our results provide new insight into mechanisms of <it>Francisella </it>virulence regulation and pathogenesis. <it>F. tularensis </it>LVS undergoes considerable gene expression changes in response to mammalian body temperature. This temperature shift is important for the regulation of genes that are critical for the pathogenesis of <it>Francisella</it>. Importantly, the compilation of temperature-regulated genes also defines a rich collection of novel candidate virulence determinants, including <it>tivA </it>(FTL_1581). An analysis of <it>tivA </it>and <it>deoB </it>(FTL_1664) revealed that these genes contribute to intracellular survival and entry into mammalian cells, respectively.</p

MiR-133a in Human Circulating Monocytes: A Potential Biomarker Associated with Postmenopausal Osteoporosis

Background: Osteoporosis mainly occurs in postmenopausal women, which is characterized by low bone mineral density (BMD) due to unbalanced bone resorption by osteoclasts and formation by osteoblasts. Circulating monocytes play important roles in osteoclastogenesis by acting as osteoclast precursors and secreting osteoclastogenic factors, such as IL-1, IL-6 and TNF-a. MicroRNAs (miRNAs) have been implicated as important biomarkers in various diseases. The present study aimed to find significant miRNA biomarkers in human circulating monocytes underlying postmenopausal osteoporosis. Methodology/Principal Findings: We used ABI TaqManH miRNA array followed by qRT-PCR validation in circulating monocytes to identify miRNA biomarkers in 10 high and 10 low BMD postmenopausal Caucasian women. MiR-133a was upregulated (P = 0.007) in the low compared with the high BMD groups in the array analyses, which was also validated by qRT-PCR (P = 0.044). We performed bioinformatic target gene analysis and found three potential osteoclast-related target genes, CXCL11, CXCR3 and SLC39A1. In addition, we performed Pearson correlation analyses between the expression levels of miR-133a and the three potential target genes in the 20 postmenopausal women. We did find negative correlations between miR-133a and all the three genes though not significant. Conclusions/Significance: This is the first in vivo miRNA expression analysis in human circulating monocytes to identif

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

High catalytic activity of oriented 2.0.0 copper(I) oxide grown on graphene film

[EN] Metal oxide nanoparticles supported on graphene exhibit high catalytic activity for oxidation, reduction and coupling reactions. Here we show that pyrolysis at 900 C under inert atmosphere of copper(II) nitrate embedded in chitosan films affords 1.1.1 facet-oriented copper nanoplatelets supported on few-layered graphene. Oriented (1.1.1) copper nanoplatelets on graphene undergo spontaneous oxidation to render oriented (2.0.0) copper(I) oxide nanoplatelets on few-layered graphene. These films containing oriented copper(I) oxide exhibit as catalyst turnover numbers that can be three orders of magnitude higher for the Ullmann-type coupling, dehydrogenative coupling of dimethylphenylsilane with n-butanol and C–N cross-coupling than those of analogous unoriented graphene-supported copper(I) oxide nanoplatelets.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2012-32315) and Generalitat Valenciana (Prometeo 2013-019) is gratefully acknowledged. Partial financial support from European Union (Being Energy project) is also acknowledged. J.F.B. and I. E.-A. thank the Technical University of Valencia and the Spanish Ministry of Science for PhD scholarships, respectively. The authors are grateful to Mrs. Amparo Forneli for her assistance in the sample preparation and to Dr. Agouram Said from SCSIE, University of Valencia for the sample preparation and HRTEM characterization of samples. AD thanks University Grants Commission, New Delhi, for the award of Assistant Professorship under its Faculty Recharge Programme. AD also thanks Department of Science and Technology, India, for the financial support through Fast Track project (SB/FT/CS-166/2013) and the Generalidad Valenciana for financial aid supporting his stay at Valencia through the Prometeo programme. VP thanks UEFISCDI for financial support through PN-II-ID-PCE-2011-3-0060 project (275/2011).Primo Arnau, AM.; Esteve Adell, I.; Blandez Barradas, JF.; Amarajothi, D.; Alvaro Rodríguez, MM.; Candu, N.; Coman, SM.... (2015). High catalytic activity of oriented 2.0.0 copper(I) oxide grown on graphene film. Nature Communications. 6. https://doi.org/10.1038/ncomms9561S85616Huang, J. et al. Nanocomposites of size-controlled gold nanoparticles and graphene oxide: formation and applications in SERS and catalysis. Nanoscale 2, 2733–2738 (2010).Li, X., Wang, X., Song, S., Liu, D. & Zhang, H. Selectively deposited noble metal nanoparticles on fe3o4/graphene composites: stable, recyclable, and magnetically separable catalysts. Chem. Eur. J. 18, 7601–7760 (2012).Liang, Y. et al. Covalent hybrid of spinel manganese-cobalt oxide and graphene as advanced oxygen reduction electrocatalysts. J. Am. Chem. Soc. 134, 3517–3523 (2012).Ghanbarlou, H., Rowshanzamir, S., Kazeminasab, B. & Parnian, M. J. Non-precious metal nanoparticles supported on nitrogen-doped graphene as a promising catalyst for oxygen reduction reaction: synthesis, characterization and electrocatalytic performance. J. Power Sources 273, 981–989 (2015).Chu, H. et al. Ionic-liquid-assisted preparation of carbon nanotube-supported uniform noble metal nanoparticles and their enhanced catalytic performance. Adv. Funct. Mater. 20, 3747–3752 (2010).Ramulifho, T., Ozoemena, K. I., Modibedi, R. M., Jafta, C. J. & Mathe, M. K. Fast microwave-assisted solvothermal synthesis of metal nanoparticles (Pd, Ni, Sn) supported on sulfonated MWCNTs: Pd-based bimetallic catalysts for ethanol oxidation in alkaline medium. Electrochim. Acta 59, 310–320 (2012).Wang, Y., Zhao, Y., He, W., Yin, J. & Su, Y. Palladium nanoparticles supported on reduced graphene oxide: facile synthesis and highly efficient electrocatalytic performance for methanol oxidation. Thin Solid Films 544, 88–92 (2013).He, Y. et al. Metal nanoparticles supported graphene oxide 3D porous monoliths and their excellent catalytic activity. Mater. Chem. Phys. 134, 585–589 (2012).Li, Z. et al. One-pot synthesis of pd nanoparticle catalysts supported on n-doped carbon and application in the domino carbonylation. ACS Catal. 3, 839–845 (2013).Xiang, G., He, J., Li, T., Zhuang, J. & Wang, X. Rapid preparation of noble metal nanocrystals via facile coreduction with graphene oxide and their enhanced catalytic properties. Nanoscale 3, 3737–3742 (2011).Li, Z. et al. Experimental and DFT studies of gold nanoparticles supported on MgO(111) nano-sheets and their catalytic activity. Phys. Chem. Chem. Phys. 13, 2582–2589 (2011).Ding, M., Tang, Y. & Star, A. Understanding interfaces in metal-graphitic hybrid nanostructures. J. Phys. Chem. Lett. 4, 147–160 (2013).Wildgoose, G. G., Banks, C. E. & Compton, R. G. Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications. Small 2, 182–193 (2006).Blandez, J. F., Primo, A., Asiri, A. M., Álvaro, M. & García, H. Copper nanoparticles supported on doped graphenes as catalyst for the dehydrogenative coupling of silanes and alcohols. Angew. Chem. Int. Ed. 53, 12581–12586 (2014).Yang, M. Q., Zhang, N., Pagliaro, M. & Xu, Y. J. Artificial photosynthesis over graphene-semiconductor composites. Are we getting better? Chem. Soc. Rev. 43, 8240–8254 (2014).Zhang, N., Zhang, Y. & Xu, Y. J. Recent progress on graphene-based photocatalysts: current status and future perspectives. Nanoscale 4, 5792–5813 (2012).Parga, A. L. V. de., Ha nacido una estrella. El grafeno. An. Quím. 107, 213–220 (2011).Rao, C. N. R., Sood, A. K., Subrahmanyam, K. S. & Govindaraj, A. Graphene: the new two-dimensional nanomaterial. Angew. Chem. Int. Ed. 48, 7752–7777 (2009).Sun, T. et al. Facile and green synthesis of palladium nanoparticles-graphene-carbon nanotube material with high catalytic activity. Nature 3, 1–6 (2013).Yoo, E. et al. Enhanced electrocatalytic activity of Pt subnanoclusters on graphene nanosheet surface. Nano Lett. 9, 2255–2259 (2009).Jin, X. et al. Lattice-matched bimetallic CuPd-graphene nanocatalysts for facile conversion of biomass-derived polyols to chemicals. ACS Nano 7, 1309–1316 (2013).Hong, C. et al. Graphene oxide stabilized Cu2O for shape selective nanocatalysis. J. Mater. Chem. A 2, 7147–7151 (2014).Reina, A. et al. Large area, few-layer graphene films on arbitrary substrates by chemical vapor deposition. Nano Lett. 9, 30–35 (2008).Wei, D. et al. Synthesis of N-doped graphene by chemical vapor deposition and its electrical properties. Nano Lett. 9, 1752–1758 (2009).Kim, K. S. et al. Large-scale pattern growth of graphene films for stretchable transparent electrodes. Nature 457, 706–710 (2009).Li, X. et al. Large-area graphene single crystals grown by low-pressure chemical vapor deposition of methane on copper. J. Am. Chem. Soc. 133, 2816–2819 (2011).Mattevi, C., Kima, H. & Chhowalla, M. A review of chemical vapour deposition of graphene on copper. J. Mater. Chem. 21, 3324–3334 (2010).Liu, W., Li, H., Xu, C., Khatami, Y. & Banerjee, K. Synthesis of high-quality monolayer and bilayer graphene on copper using chemical vapor deposition. Carbon 49, 4122–4130 (2011).Losurdo, M., Giangregorio, M. M., Capezzuto, P. & Bruno, G. Graphene CVD growth on copper and nickel: role of hydrogen in kinetics and structure. Phys. Chem. Chem. Phys. 13, 20836–20843 (2011).Gao, L., Guest, J. R. & Guisinguer, N. P. Epitaxial graphene on Cu (111). Nano Lett. 10, 3512–3516 (2010).Zhao, L. et al. Influence of copper crystal surface on the growth of large area monolayer graphene. Solid State Commun. 151, 509–513 (2011).Wood, J. D., Schmucker, S. W., Lyons, A. S., Pop, E. & Lyding, J. W. Effects of polycrystalline Cu substrate on graphene growth by chemical vapor deposition. Nano Lett. 11, 4547–4554 (2011).Primo, A., Atienzar, P., Sanchez, E., Delgado, J. M. & Garcia, H. From biomass wastes to large-area, high-quality, N-doped graphene: catalyst-free carbonization of chitosan coatings on arbitrary substrates. Chem. Commun. 48, 9254–9256 (2012).Primo, A., Sánchez, E., Delgado, J. M. & García, H. High-yield production of N-doped graphitic platelets by aqueous exfoliation of pyrolyzed chitosan. Carbon 68, 777–783 (2014).Primo, A., Forneli, A., Corma, A. & García, H. From biomass wastes to highly efficient CO2 adsorbents: graphitisation of chitosan and alginate biopolymers. ChemSusChem. 5, 2207–2214 (2012).Ravi Kumar, M. N. V. A review of chitin and chitosan applications. React. Funct. Polym. 46, 1–27 (2000).Rinaudo, M. Chitin and chitosan: properties and applications. Prog. Polym. Sci. 31, 603–632 (2006).Rinaudo, M. Main properties and current applications of some polysaccharides as biomaterials. Polym. Int. 57, 397–430 (2008).Latorre-Sanchez, M. et al. The synthesis of a hybrid graphene-nickel/manganese mixed oxide and its performance in lithium-ion batteries. Carbon 50, 518–525 (2012).Park, B. K. et al. Synthesis and size control of monodisperse copper nanoparticles by polyol method. J. Colloid Interface Sci. 311, 417–424 (2007).Lavorato, C., Primo, A., Molinari, R. & Garcia, H. Natural alginate as a graphene precursor and template in the synthesis of nanoparticulate ceria/graphene water oxidation photocatalysts. ACS Catal. 4, 497–504 (2014).Wu, S. et al. Electrochemical deposition of Cl-doped n-type Cu2O on reduced graphene oxide electrodes. J. Mater. Chem. 21, 3467–3470 (2011).Jiang, L. et al. Surface-enhanced Raman scattering spectra of adsorbates on Cu2O nanospheres: charge-transfer and electromagnetic enhancement. Nanoscale 5, 2784–2789 (2013).Sridhara Rao, D. V., Muraleedharan, K. & Humphreys, C. J. Microscopy Science, Technology, Applications and Education Vol. 2, 1232–1244Formatex, Badajos (2011).Lewin, A. H. & Cohen, T. The mechanism of the Ullman reaction. Detection of an organocopper intermediate. Tetrahedron Lett. 6, 4531–4536 (1965).Hassan, J., Sévignon, M., Gozzi, C., Schulz, E. & Lemaire, M. Aryl-aryl bond formation one century after the discovery of the Ullmann reaction. Chem. Rev. 102, 1359–1469 (2002).Ma, D., Cai, Q. & Zhang, H. Mild method for Ullman coupling reaction of amines and aryl halides. Org. Lett. 5, 2453–2455 (2003).Li, Y., Gao, W., Ci, L., Wang, C. & Ajayan, P. M. Catalytic performance of Pt nanoparticles on reduced graphene oxide for methanol electro-oxidation. Carbon 48, 1124–1130 (2010).Ong, W.-J., Tan, L.-L., Chai, S.-P. & Yong, S.-T. Heterojunction engineering of graphitic carbon nitride (g-C3N4) via Pt loading with improved daylight-induced photocatalytic reduction of carbon dioxide to methane. Dalton Trans. 44, 1249–1257 (2015).Luo, C., Zhang, Y., Zeng, X., Zeng, Y. & Wang, Y. The role of poly(ethylene glycol) in the formation of silver nanoparticles. J. Colloid Interface Sci. 288, 444–448 (2005).Wu, S.-H. & Chen, D.-H. Synthesis and characterization of nickel nanoparticles by hydrazine reduction in ethylene glycol. J. Colloid Interface Sci. 259, 282–286 (2003).Hou, Z., Theyssen, N., Brinkmann, A. & Leitner, W. Biphasic aerobic oxidation of alcohols catalyzed by poly(ethylene glycol)-stabilized palladium nanoparticles in supercritical carbon dioxide. Angew. Chem. Int. Ed. 117, 1370–1373 (2005).Dhakshinamoorthy, A., Navalon, S., Sempere, D., Alvaro, M. & Garcia, H. Reduction of alkenes catalyzed by copper nanoparticles supported on diamond nanoparticles. Chem. Commun. 49, 2359–2361 (2013).Ito, H., Watanabe, A. & Sawamura, M. Versatile dehydrogenative alcohol silylation catalyzed by Cu (I)-phosphine complex. Org. Lett. 7, 1869–1871 (2005).Rendler, S. et al. Stereoselective alcohol silylation by dehydrogenative Si-O coupling: scope, limitations, and mechanism of the Cu-H-catalyzed non-enzimatic kinetic resolution with silicon-stereogenic silanes. Chem. Eur. J. 14, 11512–11528 (2008).Cristau, H. J., Cellier, P. P., Spindler, J. F. & Taillefer, M. Highly efficient and mild copper-catalyzed N- and C-arylations with aryl bromides and iodides. Chemistry 10, 5607–5622 (2004).Shafir, A. & Buchwald, S. L. Highly selective room-temperature copper-catalyzed C-N coupling reactions. J. Am. Chem. Soc. 128, 8742–8743 (2006)