Synthesis of magnetic nanoparticles and nanocomposites via water-in-oil microemulsions

The effects of surfactants, co-surfactants, aqueous phase and temperature on the solubilisation capability of microemulsion systems were investigated. Appropriate water-in-oil (w/o) microemulsion systems for the synthesis of nanomaterials were selected in consideration of the higher solubilisation and the better thermo-stability. Mono-dispersed iron oxide nanoparticles with the size of 1-5 nm were synthesised via Igepal CO-520/cyclohexane w/o microemulsion at 25°C. The size of particles increased from 1 nm to 10 nm with the increase of the size of water pools. The original particles as prepared were identified as magnetite, which transformed into maghemite after 2-hour hydrothermal at 120°C and into hematite after 2-hour hydrothermal at 140°C, accompanied with the increased crystallite size. Precipitation was employed for basic studies of starting materials, reaction time and temperature. Compared with precipitation-derived particles, microemulsion-derived nanoparticles show smaller particle size, are less aggregated and exhibit higher activities and a lower saturation magnetisation and coercivity both at 5K and 300K. Poly-(methacrylic acid) (PMAA), Polyacrylamide (PAM) nano-spheres were synthesised via Triton X-114/cyclohexane and Brij 97/cyclohexane w/o microemulsions at 60°C, respectively. The size of PMMA spheres is 30-100nm while the size of PAM spheres increased from 50 nm to 200 nm with the increase of surfactant concentration from 19.3% to 28.9%. The increased size of water pools from 2.43 to 4.32 also resulted in the increased size of PAM from 50 nm to 500 nm. The effects of reaction time and temperature, and reagent concentration on PAM polymerisation in microemulsion were investigated in terms of the conversion, molecular weight and morphology of polymers produced. Core-shell structured silica coated iron oxide nanoparticles were synthesised via Igepal CO-520/cyclohexane systems at 25°C, with 5 nm core and 5 nm shell. Nanocomposites of PAM embedded with iron oxide were synthesised in Brij 97/cyclohexane at 60°C, with the size of 120 nm. The crystallinity of magnetic nanoparticles was affected by the coating process.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Stock Market Listing, Investor Myopia and Innovation: The Role of Nominal Share Prices

Lower nominal stock prices tend to attract more speculative trading, causing higher price volatility, which may force managers of publically listed firms to excessively focus on short-term earnings at the expense of R&D. We hypothesize that firms investing more in R&D prefer to set higher share prices to mitigate investor short-termism and foster innovation. Consistent with this hypothesis, we find that firms with high R&D capital (1) choose higher share prices at their initial listing, and (2) are subsequently less likely to engage in stock splits to bring down their share prices. Justifying these price management actions, we find that high share prices are negatively associated with proxies of investor myopia. We also show that high share prices are positively associated with future productivity of innovation, after controlling for a host of other factors. Our results suggest that managers of publicly listed firms use nominal share price as a tool to enhance innovation

Comparative genomics of five Valsa species gives insights on their pathogenicity evolution

Valsa is a genus of ascomycetes within the Valsaceae family. This family includes many wood destructive pathogens such as the well known Valsa mali and Valsa pyri which cause canker diseases in fruit trees and threaten the global fruit production. Lack of genomic information of this family is impeding our understandings about their evolution and genetic basis of their pathogenicity divergence. Here, we report genome assemblies of Valsa malicola, Valsa persoonii, and Valsa sordida which represent close relatives of Valsa mali and Valsa pyri with different host preferences. Comparative genomics analysis revealed that segmental rearrangements, inversions, and translocations frequently occurred among Valsa spp. genomes. Gene families that exhibited gene copy expansions tended to be associated with secondary metabolism, transmembrane transport, and pyrophosphatase activities. Orthologous genes in regions lost synteny exhibited significantly higher rate of synonymous substitution (KS) than those in regions retained synteny. Moreover, among these genes, membrane transporter families associated with antidrug (MFS, DHA) activities and nutrient transportation (SP and APCs) activities were significantly over-represented. Lineage specific synonymous substitution (KS) and nonsynonymous substitution (KA) analysis based on the phylogeny constructed from 11 fungal species identified a set of genes with selection signatures in Valsa clade and these genes were significantly enriched in functions associated with fatty acid beta-oxidation, DNA helicase activity, and ATPase activity. Furthermore, unique genes that possessed or retained by each of the five Valsa species are more likely part of the secondary metabolic (SM) gene clusters. SM gene clusters conserved across five Valsa species showed various degrees of diversification in both identity and completeness. All 11 syntenically conserved SM clusters showed differential expression during the infection of apple branch with Valsa mali suggesting involvements of secondary metabolism in the pathogenicity of Valsa species

Morinda Citrifolia L. (noni) Improves the Quality of Life in Adults with Osteoarthritis

Background: Morinda citrifolia Linn (noni), as a “pain killer”, has been used as a traditional medicine by Polynesians for over 2000 years. It was reported to have a broad range of therapeutic effects including analgesic and anti-inflammation. The in-vitro and in vivoanti-inflammatory and analgesic properties of noni juice (NJ) suggest that NJ may be a useful adjunctive treatment for osteoarthritis (OA). In this pilot study we explored whether NJ improves the symptoms and Quality of Life (QoL) for adults with OA. We also sought to evaluate the tolerability and safety of NJ for patients with OA in a primary care setting. Methods: This was an open label three-month intervention pilot study. Data were collected by pre/post intervention survey and laboratory testing. Inclusion criteria were: adults of both sexes aged 40 to 75, with a diagnosis of OA on the hip or knee by x-ray examination provided by their primary care physician, not on prescription medicine for OA, and who were willing to drink 3 oz of NJ a day for 90 days. Results: Of the 64 questions measuring different aspects of QoL asked on the pre/post survey, 49 (77%) had significant pre/post mean scale differences as measured by independent t-test. The OA patients reported being significantly more satisfied with their current health conditions including mobility, walking and bending, hand, finger, and arm functions, household tasks, social activity, arthritis pain, work ability, level of tension, and mood. The study participants were also more positive about their future health and reported taking less over-the-counter (OTC) pain relievers. Pre/post laboratory testing including: lipid panel, liver and kidney functions were in the normal ranges. High Sensitive C Reactive Protein (hsCRP), an inflammatory biomarker, was reduced by 10% after the intervention