1,376 research outputs found

    PPH dendrimers grafted on silica nanoparticles: surface chemistry, characterization, silver colloids hosting and antibacterial activity

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    Polyphosphorhydrazone (PPH) dendrimers have been grafted on silica nanoparticles, and the surface functions of the dendrimers have been derivatized to phosphonates with lateral poly(ethyleneglycol) (PEG) chains. All materials have been thoroughly characterized by MAS NMR, FT-IR, electron microscopy, TGA and elemental analysis. These materials successfully hosted silver and silver oxide nanoparticles. The resulting composites exhibit antibacterial activity

    The role of climate change in a developing threat: the case of bluetongue in Europe

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    Climate Change Contribution to the Emergence or Re-Emergence of Parasitic Diseases.

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    The connection between our environment and parasitic diseases may not always be straightforward, but it exists nonetheless. This article highlights how climate as a component of our environment, or more specifically climate change, has the capability to drive parasitic disease incidence and prevalence worldwide. There are both direct and indirect implications of climate change on the scope and distribution of parasitic organisms and their associated vectors and host species. We aim to encompass a large body of literature to demonstrate how a changing climate will perpetuate, or perhaps exacerbate, public health issues and economic stagnation due to parasitic diseases. The diseases examined include those caused by ingested protozoa and soil helminths, malaria, lymphatic filariasis, Chagas disease, human African trypanosomiasis, leishmaniasis, babesiosis, schistosomiasis, and echinococcus, as well as parasites affecting livestock. It is our goal to impress on the scientific community the magnitude a changing climate can have on public health in relation to parasitic disease burden. Once impending climate changes are now upon us, and as we see these events unfold, it is critical to create management plans that will protect the health and quality of life of the people living in the communities that will be significantly affected

    A dynamic, climate-driven model of Rift Valley fever

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    Outbreaks of Rift Valley fever (RVF) in eastern Africa have previously occurred following specific rainfall dynamics and flooding events that appear to support the emergence of large numbers of mosquito vectors. As such, transmission of the virus is considered to be sensitive to environmental conditions and therefore changes in climate can impact the spatiotemporal dynamics of epizootic vulnerability. Epidemiological information describing the methods and parameters of RVF transmission and its dependence on climatic factors are used to develop a new spatio-temporal mathematical model that simulates these dynamics and can predict the impact of changes in climate. The Liverpool RVF (LRVF) model is a new dynamic, process-based model driven by climate data that provides a predictive output of geographical changes in RVF outbreak susceptibility as a result of the climate and local livestock immunity. This description of the multi-disciplinary process of model development is accessible to mathematicians, epidemiological modellers and climate scientists, uniting dynamic mathematical modelling, empirical parameterisation and state-of-the-art climate information

    Synthesis, X-ray structures and reactivity of the first bis(amino)metallastibanes and bis(amino)metallabismuthanes

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    The reaction of Me2Si(N-t-Bu)2ECl (E = Sb, Bi) with NaM(CO)nCp (M = Fe, Mo, W; Cp = ?5-C5H5) affords metallastibanes and bismuthanes, Cp(CO)nME(N-t-Bu)2SiMe2 (4a-c, 5a-c). The structures of 4c (E = Sb, M = W) and 5c (E = Bi, M = W) have been determined by X-ray crystallography. Both compounds are isotypic and isostructural and crystallize in the triclinic space group with a = 7.030 (9) A°, b = 10.51 (1) A°, c = 16.22 (2) A°, a = 94.1 (1)°, ß = 90.4 (1)°, ? = 104.9 (1)°, Z = 2 for 4c and a = 7.014 (9) A°, b = 10.57 (1) A°, c = 16.25 (2) A°, a = 94.1 (1)°, ß= 90.1 (1)°, ? = 104.6 (1)°, Z = 2 for 5c. The E-W s-bond lengths are 3.010 (1) A° for E = Sb and 3.082 (1) A° for E = Bi. The reaction of the antimony derivatives with Fe2(CO)9 yields [Fe(CO)4]Cp(CO)nMSb(N-t-Bu)2SiMe2 (6a-c) as a result of the complexation of the antimony lone pair. The crystal structures of 6a (M = Fe) and 6b (M = Mo) have been determined. 6a crystallizes in the monoclinic space group with a = 10.399 (9) A°, b = 16.76 (2) A°, c = 15.74 (1) A°, ß = 94.16 (6)°, and Z = 4. Both Sb-Fe bond lengths are almost similar: 2.547 (1) A° for the covalent bond and 2.530 (1) A° for the dative bond. 6b crystallizes in the monoclinic space group with a = 12.305 (7) A°, b = 13.812 (7) A°, c = 16.75 (1) A°, ß = 99.03 (5)°, and Z = 4. The Sb-Mo covalent bond length is 2.871 (1) A° and the Sb-Fe dative bond 2.539 (1) A°
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