105 research outputs found

    Synthesis analysis of the free form curves and surfaces parametrical models

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    Parametrical models have become an important mathematical tool for free form curves and surface description. they allow the use of state-of-the-art computers to do the various processing and analysis with respect to shape (calculation of the volume and surface area, vibration analysis, NC programs preparation, etc.). Without these models, the current product design and manufacturing would be difficult. The paper presents an analysis study for the most important parametrical models of free form curves and surfaces description (Ferguson, Coons, Bezier, B-Spline and rational models). Firstly, it emphasises external and mathematical properties of each model. Secondly, it gives the most interesting interfaces between models. Thus the process of complex surface design and manufacturing would be more efficient in view this analysis. Finally for validation, the study is ended by an application to the design of a car bonnet.Parametrical models have become an important mathematical tool for free form curves and surface description. they allow the use of state-of-the-art computers to do the various processing and analysis with respect to shape (calculation of the volume and surface area, vibration analysis, NC programs preparation, etc.). Without these models, the current product design and manufacturing would be difficult. The paper presents an analysis study for the most important parametrical models of free form curves and surfaces description (Ferguson, Coons, Bezier, B-Spline and rational models). Firstly, it emphasises external and mathematical properties of each model. Secondly, it gives the most interesting interfaces between models. Thus the process of complex surface design and manufacturing would be more efficient in view this analysis. Finally for validation, the study is ended by an application to the design of a car bonnet

    Detecting colorectal cancer using electrical impedance spectroscopy: an ex vivo feasibility study

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    Objective: Colorectal cancer is the fourth most common cancer worldwide, with a lifetime risk of around 20%. Current solutions do not allow clinicians to objectively assess tissue abnormality during endoscopy and perioperatively. A solution capable of objectively assessing samples in real time could greatly improve the treatment process. A solution that can be integrated in minimally invasive diagnostics and management strategies to provide real-time point-of-care information would be greatly transformative. Electrical impedance spectroscopy (EIS) may provide such a solution. In this paper, we present a feasibility study on using EIS in assessing colorectal tissue. Approach: We performed tetrapolar EIS using ZedScan on excised human colorectal tumour tissue and the matched normal colonic mucosa in 22 freshly resected specimens following elective surgery for colorectal cancer. Histopathological examination was used to confirm the final diagnosis. Statistical significance was assessed with Wilcoxon signed rank test. Main results: Tetrapolar EIS could discriminate cancer with statistically significant results when applying frequencies between 305 Hz – 625 kHz (p < 0.05). 300 Ω was set as the transfer impedance threshold to detect cancer. Thus, the area under the corresponding receiver operating characteristic curve for this threshold was 0.7105. Significance: This feasibility study demonstrates that impedance spectra changes in colorectal cancer tissue are detectable and may be statistically significant, suggesting that EIS has the potential to be the core technology in a novel non-invasive point of care test for detecting colorectal cancer. These results warrant further development and increasing the size of the study with a device specificity designed for colorectal cancer

    Synthesis and reactivity of N-allenyl cyanamides

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    N-Allenyl cyanamides have been accessed via a one-pot deoxycyanamidation–isomerization approach using propargyl alcohol and N-cyano-N-phenyl-p-methylbenzenesulfonamide. The utility of this novel class of allenamide was explored through derivatization, with hydroarylation, hydroamination, and cycloaddition protocols employed to access an array of cyanamide products that would be challenging to access using existing methods

    Intramuscular vaccination of Atlantic lumpfish (Cyclopterus lumpus L.) induces inflammatory reactions and local immunoglobulin M production at the vaccine administration site

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    Atlantic lumpfish were vaccinated by intramuscular (im) or intraperitoneal (ip) injection with a multivalent oil‐based vaccine, while control fish were injected with phosphate‐buffered saline. Four lumpfish per group were sampled for skin/muscle and head kidney tissue at 0, 2, 7, 21 and 42 days post‐immunization (dpi) for histopathology and immunohistochemistry (IHC). Gene expressions of secretory IgM, membrane‐bound IgM, IgD, TCRα, CD3ε and MHC class IIβ were studied in tissues by using qPCR. Im. vaccinated fish showed vaccine‐induced inflammation with formation of granulomas and increasing number of eosinophilic granulocyte‐like cells over time. On IHC sections, we observed diffuse intercellular staining of secretory IgM at the injection site at 2 dpi, while IgM + cells appeared in small numbers at 21 and 42 dpi. Skin/muscle samples from im. vaccinated fish demonstrated an increase in gene expression of IgM mRNA (secretory and membrane‐bound) at 21 and 42 dpi and small changes for other genes. Our results indicated that im. vaccination of lumpfish induced local IgM production at the vaccine injection site, with no apparent proliferation of IgM + cells. Eosinophilic granulocyte‐like cells appeared shortly after im. injection and increased in numbers as the inflammation progressed.publishedVersio

    Detecting colorectal cancer using electrical impedance spectroscopy: an ex vivo feasibility study

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    Objective: Colorectal cancer is the fourth most common cancer worldwide, with a lifetime risk of around 20%. Current solutions do not allow clinicians to objectively assess tissue abnormality during endoscopy and perioperatively. A solution capable of objectively assessing samples in real time could greatly improve the treatment process. A solution that can be integrated in minimally invasive diagnostics and management strategies to provide real-time point-of-care information would be greatly transformative. Electrical impedance spectroscopy (EIS) may provide such a solution. In this paper, we present a feasibility study on using EIS in assessing colorectal tissue. Approach: We performed tetrapolar EIS using ZedScan on excised human colorectal tumour tissue and the matched normal colonic mucosa in 22 freshly resected specimens following elective surgery for colorectal cancer. Histopathological examination was used to confirm the final diagnosis. Statistical significance was assessed with Wilcoxon signed rank test. Main results: Tetrapolar EIS could discriminate cancer with statistically significant results when applying frequencies between 305 Hz – 625 kHz (p < 0.05). 300 Ω was set as the transfer impedance threshold to detect cancer. Thus, the area under the corresponding receiver operating characteristic curve for this threshold was 0.7105. Significance: This feasibility study demonstrates that impedance spectra changes in colorectal cancer tissue are detectable and may be statistically significant, suggesting that EIS has the potential to be the core technology in a novel non-invasive point of care test for detecting colorectal cancer. These results warrant further development and increasing the size of the study with a device specificity designed for colorectal cancer

    Comfort radicalism and NEETs: a conservative praxis

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    Young people who are not in education, employment or training (NEET) are construed by policy makers as a pressing problem about which something should be done. Such young people's lack of employment is thought to pose difficulties for wider society in relation to social cohesion and inclusion and it is feared that they will become a 'lost generation'. This paper(1) draws upon English research, seeking to historicise the debate whilst acknowledging that these issues have a much wider purchase. The notion of NEETs rests alongside longstanding concerns of the English state and middle classes, addressing unruly male working class youth as well as the moral turpitude of working class girls. Waged labour and domesticity are seen as a means to integrate such groups into society thereby generating social cohesion. The paper places the debate within it socio-economic context and draws on theorisations of cognitive capitalism, Italian workerism, as well as emerging theories of antiwork to analyse these. It concludes by arguing that ‘radical’ approaches to NEETs that point towards inequities embedded in the social structure and call for social democratic solutions veer towards a form of comfort radicalism. Such approaches leave in place the dominance of capitalist relations as well as productivist orientations that celebrate waged labour

    Aryl, bi-functionalised imidazo[4,5-f]-1,10-phenanthroline ligands and their luminescent rhenium(I) complexes

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    Five new imidazo[4,5-f]-1,10-phenanthroline based ligands (1–5) have been synthesised and characterised. The facile synthesis of 1–5 allows two regiochemical points of structural variety allowing highly conjugated and bulky aryl groups of varying functionalities, including azobenzene, trityl and terpyridine constituents, to be attached to the ligand core. 1–5 are fluorescent (λem = 410–415 nm), and react readily with [ReBr(CO)5] in toluene to give neutral coordination complexes of the form fac-[ReBr(CO)3(1–5)]. The series of complexes was characterised using a variety of spectroscopic and analytical techniques. Two examples of this series were characterised in the solid state using single crystal X-ray diffraction which confirmed the octahedral geometry and formulation. Photophysical studies showed that fac-[ReBr(CO)3(1–5)] are phosphorescent in solution under ambient conditions, revealing visible emission (558–585 nm) in aerated solution with corresponding lifetimes in the range 149–267 ns. These attributes are consistent with a triplet metal to ligand charge transfer (3MLCT) emitting state

    Biological and structural studies of phosphonium 'masked thiolate' compounds

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    The ability of phosphonium cations to act as intracellular transport vectors is well-established. Phosphonioalkylthiosulfate zwitterions, and (omega)-thioacetylalkylphosphonium salts, which act as 'masked thiolate' ligands, are useful precursors for the formation of phosphonium-functionalised gold nanoparticles, enabling the nanoparticles to be transported into cells for diagnostic and therapeutic purposes. In this study we have completed cytotoxicity studies of (omega)-thioacetylpropylphosphonium salts derived from triphenylphosphine and tri(4-fluorophenyl)phosphine, which show that the compounds are only toxic towards PC3 prostate cancer cells at high concentrations and at prolonged incubation periods and display IC50 values of 67uM and 252uM respectively, significantly higher than those of other phosphonium salts. MALDI-TOF-MS has been used to investigate the uptake of the compounds by PC3 cells and to quantify detectable levels of the compounds inside the cells. The structures of (omega)-thioacetylpropyl(tri-4-fluorophenyl) phosphonium bromide and the corresponding tri(4-fluorophenyl)phosphonio-propylthiosulfate zwitterion have been investigated by single crystal X-ray crystallography. The results show that molecules of the zwitterion are held together through an extensive array of electrostatic and non-covalent interactions. The unit cell of (omega)-thioacetylpropyl(tri-4-fluorophenyl)phosphonium bromide contains eight cations together with eight bromide anions and two waters of crystallisation, all held together through a complex network of hydrogen bonds. The differences in the molecular packing of the two compounds may account for the lower solubility of the zwitterion in aqueous solutions, compared with that of the phosphonium salt

    Mechanical Analysis of Feeding Behavior in the Extinct “Terror Bird” Andalgalornis steulleti (Gruiformes: Phorusrhacidae)

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    The South American phorusrhacid bird radiation comprised at least 18 species of small to gigantic terrestrial predators for which there are no close modern analogs. Here we perform functional analyses of the skull of the medium-sized (∼40 kg) patagornithine phorusrhacid Andalgalornis steulleti (upper Miocene–lower Pliocene, Andalgalá Formation, Catamarca, Argentina) to assess its mechanical performance in a comparative context. Based on computed tomographic (CT) scanning and morphological analysis, the skull of Andalgalornis steulleti is interpreted as showing features reflecting loss of intracranial immobility. Discrete anatomical attributes permitting such cranial kinesis are widespread phorusrhacids outgroups, but this is the first clear evidence of loss of cranial kinesis in a gruiform bird and may be among the best documented cases among all birds. This apomorphic loss is interpreted as an adaptation for enhanced craniofacial rigidity, particularly with regard to sagittal loading. We apply a Finite Element approach to a three-dimensional (3D) model of the skull. Based on regression analysis we estimate the bite force of Andalgalornis at the bill tip to be 133 N. Relative to results obtained from Finite Element Analysis of one of its closest living relatives (seriema) and a large predatory bird (eagle), the phorusrhacid's skull shows relatively high stress under lateral loadings, but low stress where force is applied dorsoventrally (sagittally) and in “pullback” simulations. Given the relative weakness of the skull mediolaterally, it seems unlikely that Andalgalornis engaged in potentially risky behaviors that involved subduing large, struggling prey with its beak. We suggest that it either consumed smaller prey that could be killed and consumed more safely (e.g., swallowed whole) or that it used multiple well-targeted sagittal strikes with the beak in a repetitive attack-and-retreat strategy
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