457 research outputs found

    Spatial Modulation Microscopy for Real-Time Imaging of Plasmonic Nanoparticles and Cells

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    Spatial modulation microscopy is a technique originally developed for quantitative spectroscopy of individual nano-objects. Here, a parallel implementation of the spatial modulation microscopy technique is demonstrated based on a line detector capable of demodulation at kHz frequencies. The capabilities of the imaging system are shown using an array of plasmonic nanoantennas and dendritic cells incubated with gold nanoparticles.Comment: 3 pages, 4 figure

    Plasmon oscillations in ellipsoid nanoparticles: beyond dipole approximation

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    The plasmon oscillations of a metallic triaxial ellipsoid nanoparticle have been studied within the framework of the quasistatic approximation. A general method has been proposed for finding the analytical expressions describing the potential and frequencies of the plasmon oscillations of an arbitrary multipolarity order. The analytical expressions have been derived for an electric potential and plasmon oscillation frequencies of the first 24 modes. Other higher orders plasmon modes are investigated numerically.Comment: 33 pages, 12 figure

    Pharmacokinetic Evaluation of Paclitaxel in South Indian Cancer Patients: A Prospective Study

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    Paclitaxel is a promising drug in the treatment of different solid tumors. It exhibits nonlinear pharmacokinetics, particularly when administered as a constant rate infusion for shorter duration (e.g., 3 h). Because of the nonlinearity, relatively small changes in dose may lead to large changes in peak plasma concentration and total drug exposure. The study was conducted to evaluate the pharmacokinetics of different doses of paclitaxel administered intravenously as an infusion. A prospective study was conducted in 23 cancer patients aged between 28 and 74 years, treated with paclitaxel (130, 200, 230, and 260 mg/m2) over 3 h as constant rate infusion. Plasma samples were collected from all patients at 0, 1, and 3 h and for five patients at 5 and 13 h and paclitaxel concentrations were determined using high-performance liquid chromatography method. The overall mean clearance was found to be 47.5847 ± 142.028 l/h; the mean volume of distribution was 142.028 ± 73.438 l; mean elimination rate constant was 0.336 ± 0.002/h; mean half-life was 2.086 ± 0.009 h; mean area under the curve (AUC) was 5.5917 ± 2.707 mg/ml*h; and the mean of mean residence time was 2.980 ± 0.0131 h. Paclitaxel showed nonlinear kinetics and the pharmacokinetic parameters calculated were similar to those quoted in the literature. The peak plasma concentration at 130 mg dose level was 2 μ/ml, but an increase in dose was not associated with proportional increase in plasma concentration. No significant difference was found between pharmacokinetic parameters such as clearance, volume of distribution, and AUC at different dose levels

    PEG Branched Polymer for Functionalization of Nanomaterials with Ultralong Blood Circulation

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    Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched-polymers for functionalization of various nanomaterials including carbon nanotubes, gold nanoparticles (NP) and gold nanorods (NRs), affording high aqueous solubility and stability for these materials. We synthesize different surfactant polymers based upon poly-(g-glutamic acid) (gPGA) and poly(maleic anhydride-alt-1-octadecene) (PMHC18). We use the abundant free carboxylic acid groups of gPGA for attaching lipophilic species such as pyrene or phospholipid, which bind to nanomaterials via robust physisorption. Additionally, the remaining carboxylic acids on gPGA or the amine-reactive anhydrides of PMHC18 are then PEGylated, providing extended hydrophilic groups, affording polymeric amphiphiles. We show that single-walled carbon nanotubes (SWNTs), Au NPs and NRs functionalized by the polymers exhibit high stability in aqueous solutions at different pHs, at elevated temperatures and in serum. Morever, the polymer-coated SWNTs exhibit remarkably long blood circulation (t1/2 22.1 h) upon intravenous injection into mice, far exceeding the previous record of 5.4 h. The ultra-long blood circulation time suggests greatly delayed clearance of nanomaterials by the reticuloendothelial system (RES) of mice, a highly desired property for in vivo applications of nanomaterials, including imaging and drug delivery

    ‘What Do I Get?’ Punk Objects as Meaningful and Valuable Souvenirs

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    Despite social scientists’ increasing interest on souvenirs in tourism, little has been written on the role and meanings of souvenirs within specific subcultures, such as punk subcultures. This chapter focuses on the exploration of punk objects as potential souvenirs in relation to “punk tourism” by investigating the meanings attached to subcultural artefacts as opposed to mass produced products. As part of an ethnographic fieldwork on punk tourism that the two authors have been conducting in Malaysia since 2016, in this chapter we focus on the role and meanings of punk souvenirs within the Malaysian punk scene. As the empirical material presented in this chapter shows, a DIY produced punk product has the advantage of channelling more than one value. While the value of souvenirs lies in their propensity to act as “mnemonic devices” related to a place visited, subcultural products like those produced by punks have the potential to fulfil additional values. In an age where authenticity and claims of appropriation of culture are placed under scrutiny, a punk object holds the potential of being a meaningful and valuable souvenir

    Paclitaxel in self-micro emulsifying formulations: oral bioavailability study in mice

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    The anticancer drug paclitaxel is formulated for i.v. administration in a mixture of Cremophor EL and ethanol. Its oral bioavailability is very low due to the action of P-glycoprotein in the gut wall and CYP450 in gut wall and liver. However, proof-of-concept studies using the i.v. formulation diluted in drinking water have demonstrated the feasibility of the oral route as an alternative when given in combination with inhibitors of P-glycoprotein and CYP450. Because of the unacceptable pharmaceutical properties of the drinking solution, a better formulation for oral application is needed. We have evaluated the suitability of various self-micro emulsifying oily formulations (SMEOF’s) of paclitaxel for oral application using wild-type and P-glycoprotein knockout mice and cyclosporin A (CsA) as P-glycoprotein and CYP450 inhibitor. The oral bioavailability of paclitaxel in all SMEOF’s without concomitant CsA was low in wild-type mice, showing that this vehicle does not enhance intestinal uptake by itself. Paclitaxel (10 mg/kg) in SMEOF#3 given with CsA resulted in plasma levels that were comparable to the Cremophor EL-ethanol containing drinking solution plus CsA. Whereas the AUC increased linearly with the oral paclitaxel dose in P-glycoprotein knockout mice, it increased less than proportional in wild-type mice given with CsA. In both strains more unchanged paclitaxel was recovered in the feces at higher doses. This observation most likely reflects more profound precipitation of paclitaxel within the gastro-intestinal tract at higher doses. The resulting absolute reduction in absorption of paclitaxel from the gut was possibly concealed by partial saturation of first-pass metabolism when P-glycoprotein was absent. In conclusion, SMEOF’s maybe a useful vehicle for oral delivery of paclitaxel in combination with CsA, although the physical stability within the gastro-intestinal tract remains a critical issue, especially when applied at higher dose levels

    The effectiveness of the Austrian disease management programme for type 2 diabetes: a cluster-randomised controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Disease management programmes (DMPs) are costly and impose additional work load on general practitioners (GPs). Data on their effectiveness are inconclusive. We therefore conducted a cluster-randomised controlled trial to evaluate the effectiveness of the Austrian DMP for diabetes mellitus type 2 on HbA1c and quality of care for adult patients in primary care.</p> <p>Methods</p> <p>All GPs of Salzburg-province were invited to participate. After cluster-randomisation by district, all patients with diabetes type 2 were recruited consecutively from 7-11/2007. The DMP, consisting mainly of physician and patient education, standardised documentation and agreement on therapeutic goals, was implemented in the intervention group while the control group received usual care. We aimed to show superiority of the intervention regarding metabolic control and process quality. The primary outcome measure was a change in HbA1c after one year. Secondary outcomes were days in the hospital, blood pressure, lipids, body mass index (BMI), enrolment in patient education and regular guideline-adherent examination. Blinding was not possible.</p> <p>Results</p> <p>92 physicians recruited 1489 patients (649 intervention, 840 control). After 401 ± 47 days, 590 intervention-patients and 754 controls had complete data. In the intention to treat analysis (ITT) of all 1489 patients, HbA1c decreased 0.41% in the intervention group and 0.28% in controls. The difference of -0.13% (95% CI -0.24; -0.02) was significant at p = 0.026. Significance was lost in mixed models adjusted for baseline value and cluster-effects (adjusted mean difference -0.03 (95% CI -0.15; 0.09, p = 0.607). Of the secondary outcome measures, BMI and cholesterol were significantly reduced in the intervention group compared to controls in ITT after adjustments (-0.53 kg/m²; 95% CI -1.03;-0.02; p = 0.014 and -0.10 mmol/l; 95% CI -0.21; -0.003; p = 0.043). Additionally, more patients received patient education (49.5% vs. 20.1%, p < 0.0001), eye- (71.0% vs. 51.2%, p < 0.0001), foot examinations (73.8% vs. 45.1%, p < 0.0001), and regular HbA1c checks (44.1% vs. 36.0%, p < 0.01) in the intervention group.</p> <p>Conclusion</p> <p>The Austrian DMP implemented by statutory health insurance improves process quality and enhances weight reduction, but does not significantly improve metabolic control for patients with type 2 diabetes mellitus. Whether the small benefit seen in secondary outcome measures leads to better patient outcomes, remains unclear.</p> <p>Trial Registration</p> <p>Current Controlled trials Ltd., ISRCTN27414162.</p

    A Lipid Receptor Sorts Polyomavirus from the Endolysosome to the Endoplasmic Reticulum to Cause Infection

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    The mechanisms by which receptors guide intracellular virus transport are poorly characterized. The murine polyomavirus (Py) binds to the lipid receptor ganglioside GD1a and traffics to the endoplasmic reticulum (ER) where it enters the cytosol and then the nucleus to initiate infection. How Py reaches the ER is unclear. We show that Py is transported initially to the endolysosome where the low pH imparts a conformational change that enhances its subsequent ER-to-cytosol membrane penetration. GD1a stimulates not viral binding or entry, but rather sorting of Py from late endosomes and/or lysosomes to the ER, suggesting that GD1a binding is responsible for ER targeting. Consistent with this, an artificial particle coated with a GD1a antibody is transported to the ER. Our results provide a rationale for transport of Py through the endolysosome, demonstrate a novel endolysosome-to-ER transport pathway that is regulated by a lipid, and implicate ganglioside binding as a general ER targeting mechanism
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