868 resultados para Compound Eyes
Resumo:
The new anionic functionalized aryldiamine ligands [2,6-(Me(2)NCH(2))(2)-4-R-C6H2](-) (R = Me(3)SiC=C, C6H5, Me(3)Si), formally derived from [2,6-(Me(2)NCH(2))(2)C6H3](-), have been prepared as their lithium compounds. The compound [Li{2,6-(Me(2)NCH(2))(2)-4-Ph-C6H2}](2) crystallizes in the monoclinic space group C2/c (no. 15) with a = 13.1225(5), b = 13.5844(7), c = 15.9859(12) Angstrom, beta = 105.329(5)degrees, V = 3264.0(3)Angstrom(3), Z = 4. The structure refinement converged to R(1) = 0.0374 for 2037 observed reflections [F-o>4 sigma(F-o)] and wR(2) = 0.0922 for 2560 unique data. The organolithium compounds have been used in transmetalation reactions to give the corresponding functionalized organoruthenium(II) complexes [Ru-II{2,6-(Me(2)NCH(2))(2)-4-R-C6H2}(terpy)]Cl-+(-) (terpy = 2,2';6',2 ''-terpyridine). The Ru-II species with R = HC = C has also been synthesized.
Resumo:
Behavioral effects of a novel anti-inflammatory SEN1176 were investigated. This pyrrolo[3,2-e][1,2,4]triazolo[1,5-a]pyrimidine suppresses amyloid-ß (Aß)1-42-induced macrophage production of nitric oxide, TNF-a, IL-1ß, and IL-6 in a dose-dependent fashion, an activity profile consistent with SEN1176 being a neuroinflammation inhibitor. Using male Sprague-Dawley rats, SEN1176 was examined relative to detrimental behavioral effects induced following bilateral intrahippocampal (IH) injections of aggregated Aß1-42. The rats were trained to respond under an alternating-lever cyclic-ratio (ALCR) schedule of food reinforcement, enabling measurement of parameters of operant performance that reflect aspects of learning and memory. Under the ALCR schedule, orally administered SEN1176 at 5, 20, or 30 mg/kg was effective in reducing the behavioral deficit caused by bilateral IH aggregated Aß1-42 injections in a dose-related manner over a 90-day treatment period. SEN1176 at 20 and 30 mg/kg significantly reduced lever switching errors and, at doses of 5, 10, and 30 mg/kg, significantly reduced incorrect lever perseverations, indicating a reduction of the behavioral deficit induced as a result of inflammation following IH Aß1-42 injections. When treatment with SEN1176 was instigated 30 days after IH Aß1-42 injections, it resulted in progressive protection, and withdrawal of SEN1176 treatment 60 days after IH Aß1-42 injections revealed partial retention of the protective effect. SEN1176 also significantly reduced numbers of activated astrocytes adjacent to the aggregated Aß1-42 injection sites. These results indicate the potential of SEN1176 for alleviating chronic neuroinflammatory processes related to brain Aß deposition that affect learning and memory in Alzheimer's disease.
Resumo:
A clinical trial using human embryonic stem cell (hESC) therapy for an inherited retinal degenerative disease is about to commence. The Advanced Cell Technology (ACT) trial will treat patients with Stargardt's macular dystrophy using transplanted retinal pigment epithelium derived from hESCs. Currently, no effective treatment is available for Stargardt's disease so a stem cell-based therapy that can slow progression of this blinding condition could represent a significant breakthrough. While there are some hurdles to clear, the ACT trial is a fine example of translational research that could eventually pave the way for a range of stem cell therapies for the retina and other tissues.
Resumo:
A new nonlinear theory for the perpendicular transport of charged particles is presented. This approach is based on an improved nonlinear treatment of field line random walk in combination with a generalized compound diffusion model. The generalized compound diffusion model is much more systematic and reliable, in comparison to previous theories. Furthermore, the new theory shows remarkably good agreement with test-particle simulations and heliospheric observations.
Resumo:
Intact nitrofurazone is present in whole eyes of chickens fed varying levels of this banned antibiotic and may therefore be used as an alternative to the controversial marker residue, semicarbazide, to monitor for abuse of this drug in primary production.
Resumo:
Nitrofuran antibiotic residues in food continue to be of international concern. The finding of sources of semicarbazide (SEM), other than through the misuse of nitrofurazone, present a challenge to the use of SEM as a definitive marker residue for this drug. Detection of intact (parent) nitrofurazone would avoid confusion over the source of SEM residues. Broiler chickens were fed sub-therapeutic nitrofuran-containing diets and their tissues were analysed for parent compounds and metabolites by liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS). Depletion half-lives in muscle were longer for tissue-bound metabolite residues, 3.4 days - 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidone (AMOZ) - to 4.5 days (SEM), than total metabolite residues, 2.0 days (AOZ) to 3.2 days (SEM). Metabolite concentrations were higher in eyes than in muscle. Metabolite half-lives in eyes ranged from 8.5 days (1-aminohydantoin (AHD)) to 20.3 days (SEM). Nitrofuran parent compounds were also detected in eyes. Furaltadone was detected in single eyes after 21 days' withdrawal of a 6 mg kg -1 furaltadone diet. When 50 eyes from broilers containing metabolites in muscle close to the 1 µg kg -1 minimum required performance level (MRPL) were pooled into single samples, 1.2 ng of furazolidone and 31.1 ng of furaltadone were detected, but nitrofurazone was not detected due to the long depletion half-life of SEM in muscle. Further studies are required to improve LC-MS/MS nitrofurazone sensitivity and refine the sample size necessary to use nitrofurazone detection in pooled eyes as a complement to SEM detection in muscle.
Resumo:
A new compound, IrMnSi, has been synthesized, and its crystal structure and magnetic properties have been investigated by means of neutron powder diffraction, magnetization measurements, and first-principles theory. The crystal structure is found to be of the TiNiSi type (ordered Co2P, space group Pnma). The Mn-projected electronic states are situated at the Fermi level, giving rise to metallic binding, whereas a certain degree of covalent character is observed for the chemical bond between the It and Si atoms. A cycloidal, i.e., noncollinear, magnetic structure was observed below 460 K, with the propagation vector q=[0,0,0.4530(5)] at 10 K. The magnetism is dominated by large moments on the Mn sites, 3.8 mu(B)/atom from neutron diffraction. First-principles theory reproduces the propagation vector of the experimental magnetic structure as well as the angles between the Mn moments. The calculations further result in a magnetic moment of 3.21 mu(B) for the Mn atoms, whereas the Ir and Si moments are negligible, in agreement with observations. A calculation that more directly incorporates electron-electron interactions improves the agreement between the theoretical and experimental magnetic moments. A band mechanism is suggested to explain the observed magnetic order.
Resumo:
Aim - To describe a new method of evaluating the topographic distribution of fundus autofluorescence in eyes with retinal disease. Methods - Images of fundus autofluorescence were obtained in five patients and 34 normal volunteers using a confocal scanning laser ophthalmoscope (cSLO). To evaluate the topographic distribution of fundus autofluorescence throughout the posterior pole a rectangular box, 10 x 750 pixels, was used as the area of analysis. The box was placed, horizontally, across the macular region. The intensity of fundus autofluorescence of each pixel within the rectangular box was plotted against its degree of eccentricity. Profiles of fundus autofluorescence from patients were compared with those obtained from the age matched control group and with cSLO images. Results - Profiles of fundus autofluorescence appeared to represent the topographic distribution of fundus autofluorescence throughout the posterior pole appreciated in the cSLO images, and allowed rapid identification and quantification of areas of increased or decreased fundus autofluorescence. Conclusions - Fundus autofluorescence profiles appear to be useful to study the spatial distribution of fundus autofluorescence in eyes with retinal disease.
Resumo:
Purpose – The purpose of this paper is to explore accountability from the perspective of charity donors.
Design/methodology/approach – The research utilises semi-structured interviews with a range of donors. In addition, it summarises the main findings from key related research (that uses document content analysis and questionnaire surveys) as a basis for better appreciating donor engagement.
Findings – This research offers evidence that while donors are viewed as the key stakeholder to whom a charity should be accountable, the relevance of the information commonly disclosed in formal charity communications is questionable. This is viewed as significant in terms of small dependent donors, although less critical in the case of non-dependent large donors who have power to demand individualised information. However, although all donors do not particularly engage with these formal communications, they are viewed by them as having significance and their production and publication serves as an important legitimising tool in the sector (enhancing trust and reputation).
Research limitations/implications – This research is based on semi-structured interviews with individual small donors and large institutional donors to large UK charities and therefore any generalising of the conclusions beyond large charities, and beyond the UK, should be undertaken with care. In addition, it focuses solely on the perceptions of donors, and other stakeholder groups are also important in this process.
Originality/value – Despite the widespread acceptance that charities have a duty to discharge accountability to their stakeholders, there is limited knowledge of their information needs and whether the performance information currently being disclosed fulfils them. This study provides a unique insight into the perspective of a key stakeholder group (donors) with respect to accountability.