269 research outputs found

    Improved success rate and stability for phase retrieval by including randomized overrelaxation in the hybrid input output algorithm

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    In this paper, we study the success rate of the reconstruction of objects of finite extent given the magnitude of its Fourier transform and its geometrical shape. We demonstrate that the commonly used combination of the hybrid input output and error reduction algorithm is significantly outperformed by an extension of this algorithm based on randomized overrelaxation. In most cases, this extension tremendously enhances the success rate of reconstructions for a fixed number of iterations as compared to reconstructions solely based on the traditional algorithm. The good scaling properties in terms of computational time and memory requirements of the original algorithm are not influenced by this extension.Comment: 14 pages, 8 figure

    Large orbital magnetic moments in carbon nanotubes generated by resonant transport

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    The nonequilibrium Green's function method is used to study the ballistic transport in metallic carbon nanotubes when a current is injected from the electrodes with finite bias voltages. We reveal, both analytically and numerically, that large loop currents circulating around the tube are induced, which come from a quantum mechanical interference and are much larger than the current along the tube axis when the injected electron is resonant with a time-reversed pair of degenerate states, which are, in fact, inherent in the zigzag and chiral nanotubes. This results in large orbital magnetic moments, making the nanotube a molecular solenoid.Comment: 5 pages, 4 figures; typos correcte

    Incidentally Found Primary Cerebral Malignant Melanoma Associated with Ota Nevus—Wide Dissemination after an Initial Phase of Slow Growth

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    Primary cerebral malignant melanoma accounts for 1% of all melanomas and for 0.7% of all primary tumours of the central nervous system (CNS). We report an incidentally found primary malignant melanoma in the right temporal lobe of a 76-year-old woman with an Ota nevus on her right eyelid and sclera. The lesion was initially characterised by slow growth, followed by tumoural bleeding and wide leptomeningeal dissemination. Magnetic resonance imaging (MRI) during brain checkup demonstrated an 8-mm mass in the right uncus with high intensity on T1-weighted images. The mass grew slowly over the next two years, but asymptomatic tumoural haemorrhage eventually developed. The patient underwent tumour removal via right frontotemporal craniotomy. Extensive subarachnoid dissemination from the right temporal tumour was found; the pathologic diagnosis was malignant melanoma. Despite adjuvant therapy comprising whole-brain radiation and nivolumab, the patient died of severe leptomeningeal dissemination at 4.5 months after the operation (33 months after the initial MRI study). Our literature review found 46 cases of primary CNS malignant melanoma, predominantly in middle-aged to elderly individuals. The most frequent symptom was headache, followed by visual disturbance, nausea/vomiting, and hemiparesis. Only one other case of primary cerebral malignant melanoma had been found incidentally; 11 previously reported patients manifested congenital nevi (Ota nevus, n = 5; other nevi, n = 6). Six patients suffered tumoural haemorrhage, 4 experienced leptomeningeal dissemination, and 5 developed extracranial metastases. The median survival time of the patients was 31 months

    Toona sinensis

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    Toona sinensis is one of the most popular vegetarian cuisines in Taiwan and it has been shown to possess antioxidant, antiangiogenic, and anticancer properties. In this study, we investigated the antiatherosclerotic potential of aqueous leaf extracts from Toona sinensis (TS; 25–100 μg/mL) and its major bioactive compound, gallic acid (GA; 5 μg/mL), in LPS-treated rat aortic smooth muscle (A7r5) cells. We found that pretreatment with noncytotoxic concentrations of TS and GA significantly inhibited inflammatory NO and PGE2 production by downregulating their precursors, iNOS and COX-2, respectively, in LPS-treated A7r5 cells. Furthermore, TS and GA inhibited LPS-induced intracellular ROS and their corresponding mediator, p47phox. Notably, TS and GA pretreatment significantly inhibited LPS-induced migration in transwell assays. Gelatin zymography and western blotting demonstrated that treatment with TS and GA suppressed the activity or expression of MMP-9, MMP-2, and t-PA. Additionally, TS and GA significantly inhibited LPS-induced VEGF, PDGF, and VCAM-1 expression. Further investigation revealed that the inhibition of iNOS/COX-2, MMPs, growth factors, and adhesion molecules was associated with the suppression of NF-κB activation and MAPK (ERK1/2, JNK1/2, and p38) phosphorylation. Thus, Toona sinensis may be useful for the prevention of atherosclerosis

    Pleiotropic Benefit of Monomeric and Oligomeric Flavanols on Vascular Health - A Randomized Controlled Clinical Pilot Study

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    BACKGROUND: Cardiovascular diseases are expanding to a major social-economic burden in the Western World and undermine man's deep desire for healthy ageing. Epidemiological studies suggest that flavanol-rich foods (e.g. grapes, wine, chocolate) sustain cardiovascular health. For an evidenced-based application, however, sound clinical data on their efficacy are strongly demanded. METHODS: In a double-blind, randomized, placebo-controlled intervention study we supplemented 28 male smokers with 200 mg per day of monomeric and oligomeric flavanols (MOF) from grape seeds. At baseline, after 4 and 8 weeks we measured macro- and microvascular function and a cluster of systemic biomarkers for major pathological processes occurring in the vasculature: disturbances in lipid metabolism and cellular redox balance, and activation of inflammatory cells and platelets. RESULTS: In the MOF group serum total cholesterol and LDL decreased significantly (P ≤ 0.05) by 5% (n = 11) and 7% (n = 9), respectively in volunteers with elevated baseline levels. Additionally, after 8 weeks the ratio of glutathione to glutathione disulphide in erythrocytes rose from baseline by 22% (n = 15, P<0.05) in MOF supplemented subjects. We also observed that MOF supplementation exerts anti-inflammatory effects in blood towards ex vivo added bacterial endotoxin and significantly reduces expression of inflammatory genes in leukocytes. Conversely, alterations in macro- and microvascular function, platelet aggregation, plasma levels of nitric oxide surrogates, endothelin-1, C-reactive protein, fibrinogen, prostaglandin F2alpha, plasma antioxidant capacity and gene expression levels of antioxidant defense enzymes did not reach statistical significance after 8 weeks MOF supplementation. However, integrating all measured effects into a global, so-called vascular health index revealed a significant improvement of overall vascular health by MOF compared to placebo (P ≤ 0.05). CONCLUSION: Our integrative multi-biomarker approach unveiled the pleiotropic vascular health benefit of an 8 weeks supplementation with 200 mg/d MOF in humans. TRIAL REGISTRATION: ClinicalTrials.gov NCT00742287
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