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151.
Kennedy LC Bear AS Young JK Lewinski NA Kim J Foster AE Drezek RA 《Nanoscale research letters》2011,6(1):283
Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies
and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and
are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated
with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect
for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of
tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can
be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently
loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production).
Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to
tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system
also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could
enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation. 相似文献
152.
Yann Battie Olivier Ducloux Philippe Thobois Nelly Dorval Jean Sébastien Lauret Brigitte Attal-Trétout Annick Loiseau 《Carbon》2011,49(11):3544-3552
A comparative study was made of sorted semi-conducting single walled carbon nanotube (SWCNT) films and unsorted SWCNT films for gas sensing applications. The transmission line method is used to monitor separately the SWCNTs film resistance and the contact resistance between electrodes and the SWCNTs, thus revealing that the sensing mechanism mainly relies on a modification of the tube conductivity during gas exposure. The fabricated sensors demonstrate a detection limit of 20 ppb NO2 and 600 ppb NH3 mainly attributed to experimental setup limitations. Moreover, semi-conducting nanotubes happened to be 2.5 times more sensitive to NH3 than unsorted ones, thus proving that selectivity can be improved by sorting the SWCNTs. The temperature dependence of the sensor sensitivity was studied, and a good agreement was found between experimental results and the Langmuir adsorption model. 相似文献
153.
Gislaine M. Bragagnolo Zehbour Panossian Neusvaldo Lira de Almeida Márcio Bispo de Almeida Jean V. Ferrari Mário Carlos Andreoli Fernando de L. Fragata 《Journal of Coatings Technology and Research》2011,8(5):629-638
The influences of the chromate quenching step and the surface chloride contamination levels of galvanized steel on the performance of duplex systems were studied. Steel panels were galvanized in a commercial steel bath adopting three different postdipping procedures. A comparative study of the galvanized steel, both painted and nonpainted, was performed by electrochemical techniques. It was verified that the chloride contamination level of the galvanized steel surfaces is the main cause of duplex system failures. An explanation for the influence of the chromate quenching on the performance of duplex systems was presented. 相似文献
154.
155.
Jean‐Marc Gonnet Jacques Guillet Claude Raveyre Gilles Assezat Rene Fulchiron Gerard Seytre 《Polymer Engineering and Science》2002,42(6):1171-1180
In recent years, electrical techniques like microdielectrometry have increasingly been utilized for their ability to continuously monitor, in a nondestructive way, the advancement of the reaction of thermoset resins under cure. This paper discusses an extension of this technique for the “in‐situ” monitoring of the crystallization of thermoplastics applied during an injection molding process. Electric sensors were positioned at the walls of the mold cavity so that an analysis of the volume dielectric properties of material during the filling, the post‐filling, and the cooling steps could be carried out. Poly(vinylidene fluoride) was chosen for this study. A correlation between the evolution of the dielectric parameters and the succession of the steps in this process was undertaken. The dielectric response was sufficiently sensitive to identify the steps of the closing of the mold, filling, post‐filling, cooling, and ejection of the part. In addition, information concerning the crystallization phenomenon near the wall or in the middle of the sample was collected. The gradual filling of the cavity of the mold was also identified by dielectric measurements. The temperature dependence of dielectric properties of the sample was beneficial in evaluating the increase of the temperature of the mold with the succession of injection cycles. The influence of the packing pressure has been clearly identified and confirms the usefulness of the dielectric method as a probe for detecting the shrinkage of the part during the optimization phase of the machine parameters. The dielectric method detailed herein provides a new non‐invasive technique and could be applied to a closed‐loop control of the injection molding process. 相似文献
156.
Oxygenation reactions (hydroxylation, epoxidation, N- or S-oxide formation, etc.) catalyzed by cytochrome P450 enzymes and related biomimetic models involve an electrophilic oxidative species as the active species, namely a high-valent metal-oxo intermediate. Among the different methods to study the oxygenation reactions mediated by high-valent metal-oxo porphyrin complexes, the recent discovery of oxo-hydroxo tautomerism provides a useful tool to investigate the mechanism of O-atom transfer reactions in aqueous media. 相似文献
157.
Frédéric Destaillats Jean B. Jean-Denis Joseph Arul Robert L. Wolff Paul Angers 《Journal of the American Oil Chemists' Society》2002,79(11):1091-1094
GC analysis was performed to determine regiospecific distribution and FA composition in seed oils of the Aceraceae species,
Acer saccharum and A. saccharinum. The oil content in the seeds was low at 5.0% in A. saccharum and 5.8% in A. saccharinum, and the main FA were linoleic (30.8 and 29.4%), oleic (21.3 and 27.6%), palmitic (10.1 and 10.5%), and cis-vaccenic (9.4 and 7.9%) acids, respectively. In addition, both oils contained long-chain monoenes of the n−9 and n−7 groups,
including 11-eicosenoic, 13-docosenoic, 15-tetracosenoic, 13-eicosenoic, and 15-docosenoic acids, whereas γ-linolenic acid
accounted for 0.8% of total FA in A. saccharum, and 0.5% in A. saccharinum. Regiospecific analysis, performed using the methodology of dibutyroyl derivatives of MAG, indicated that linoleic, oleic,
and linolenic acids were mainly esterified at the internal position of TAG in both seed oils, whereas long-chain monoenes
of the n−7 group were almost exclusively esterified on the external positions. 相似文献
158.
Jean Marcel R. Gallo David M. Alonso Max A. Mellmer Jher Hau Yeap Hui Chin Wong James A. Dumesic 《Topics in Catalysis》2013,56(18-20):1775-1781
The production of furfural from the C5 monosaccharides xylose, arabinose and ribose, as well as from real biomass (corn fiber), was studied using H-Beta zeolite as catalyst in a monophasic system with the biomass-derived solvent, gamma-valerolactone. Due to the combination of Brønsted and Lewis acid sites on this catalyst (Brønsted:Lewis ratio = 1.66), H-Beta acts as a bifunctional catalyst, being able to isomerize (Lewis acid) and dehydrate (Brønsted acid) monosaccharides. The combination of Lewis and Brønsted acid functionality of H-Beta was shown to be effective for the isomerization of xylose and arabinose, followed by dehydration. While no advantages were found in the conversion of xylose, higher furfural yields were achieved from arabinose, using H-Beta, 73 %, compared to sulfuric acid (44 %) and Mordenite (49 %). The furfural yields from corn fiber for H-Beta, H-Mordenite and sulfuric acid were 62, 44, and 55 %, respectively, showing that H-Beta is particularly effective for conversion of this biomass feedstock composed of 45 wt% hemicellulose, of which 66 % is xylose and 33 % arabinose. 相似文献
159.
S. Schneider D. Bazin G. Meunier R. Noirot M. Capelle F. Garin G. Maire 《Catalysis Letters》2001,71(3-4):155-162
Face to the difficulty to find an efficient catalyst in the reduction of NO by hydrocarbon in diesel exhaust gases, we have examined the interaction of some concerned reactant gases, NO, C3H6 and O2, with a catalyst constituted of nanometer scale platinum particles deposited on alumina. Indeed, in order to understand the catalytic process, it seems essential to have information on the adsorption process and on the evolution of the structural parameters of the particles when submitted to such gases. This work has been performed on a 1% Pt/Al2O3 catalyst by using in situ EXAFS measurements. We have concentrated our study, on the one hand, on the influence of NO, C3H6 in the presence or not of an excess of oxygen and, on the other hand, on the influence of the total mixture. The most striking result is the growth of the platinum particles under NO. Moreover, when the catalyst is submitted either to a mixture of NO + O2 or C3H6 + O2, the particles are not fully oxidised. With the total mixture, the particles both grow and are oxidised. 相似文献
160.
Thermophoresis is the movement of particles in a thermal gradient. It has the advantages of being simple to set up and to carry out. Here, it is used to prevent the recontamination of emitted particles smaller than 0.5 μm during the dry laser cleaning of particles not chemically bound to the substrate. Its use permits the efficiency of such dry laser cleaning to be greatly improved. A comparison between the thermophoretic and laminar flow techniques is carried out, showing that thermophoresis is more efficient. 相似文献