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排序方式: 共有1905条查询结果,搜索用时 31 毫秒
951.
Rajendra Kurapati Julie Russier Marco A. Squillaci Emanuele Treossi Cécilia Ménard‐Moyon Antonio Esaú Del Rio‐Castillo Ester Vazquez Paolo Samorì Vincenzo Palermo Alberto Bianco 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(32):3985-3994
Understanding human health risk associated with the rapidly emerging graphene‐based nanomaterials represents a great challenge because of the diversity of applications and the wide range of possible ways of exposure to this type of materials. Herein, the biodegradation of graphene oxide (GO) sheets is reported by using myeloperoxidase (hMPO) derived from human neutrophils in the presence of a low concentration of hydrogen peroxide. The degradation capability of the enzyme on three different GO samples containing different degree of oxidation on their graphenic lattice, leading to a variable dispersibility in aqueous media is compared. hMPO fails in degrading the most aggregated GO, but succeeds to completely metabolize highly dispersed GO samples. The spectroscopy and microscopy analyses provide unambiguous evidence for the key roles played by hydrophilicity, negative surface charge, and colloidal stability of the aqueous GO in their biodegradation by hMPO catalysis. 相似文献
952.
Olson Ingrid R.; Zhang John X.; Mitchell Karen J.; Johnson Marcia K.; Bloise Suzanne M.; Higgins Julie A. 《Canadian Metallurgical Quarterly》2004,19(2):310
Two studies compared young and older adults' memory for location information after brief intervals. Experiment 1 found that accuracy of intentional spatial memory for individual locations was similar in young and older participants for set sizes of 3 and 6. Both groups also encoded individual locations in relation to the larger configuration of locations. Experiment 2 showed that like young adults, older adults' latency to respond to a test probe in a letter working memory task was negatively influenced by spatial information that was irrelevant to the task. This interference effect indicated preserved incidental memory for spatial information in older adults. Together, these data suggest that initial encoding of spatial information for relatively small numbers of items is largely preserved in healthy older adults and that representations of spatial information persist over short intervals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
953.
Optimal transport is a long-standing theory that has been studied in depth from both theoretical and numerical point of views. Starting from the 50s this theory has also found a lot of applications in operational research. Over the last 30 years it has spread to computer vision and computer graphics and is now becoming hard to ignore. Still, its mathematical complexity can make it difficult to comprehend, and as such, computer vision and computer graphics researchers may find it hard to follow recent developments in their field related to optimal transport. This survey first briefly introduces the theory of optimal transport in layman's terms as well as most common numerical techniques to solve it. More importantly, it presents applications of these numerical techniques to solve various computer graphics and vision related problems. This involves applications ranging from image processing, geometry processing, rendering, fluid simulation, to computational optics, and many more. It is aimed at computer graphics researchers desiring to follow optimal transport research in their field as well as optimal transport researchers willing to find applications for their numerical algorithms. 相似文献
954.
Craig E. Grossman Shirron L. Carter Julie Czupryna Le Wang Mary E. Putt Theresa M. Busch 《International journal of molecular sciences》2016,17(1)
Photodynamic therapy (PDT) of the thoracic cavity can be performed in conjunction with surgery to treat cancers of the lung and its pleura. However, illumination of the cavity results in tissue exposure to a broad range of fluence rates. In a murine model of intrathoracic PDT, we studied the efficacy of 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH; Photochlor®)-mediated PDT in reducing the burden of non-small cell lung cancer for treatments performed at different incident fluence rates (75 versus 150 mW/cm). To better understand a role for growth factor signaling in disease progression after intrathoracic PDT, the expression and activation of epidermal growth factor receptor (EGFR) was evaluated in areas of post-treatment proliferation. The low fluence rate of 75 mW/cm produced the largest reductions in tumor burden. Bioluminescent imaging and histological staining for cell proliferation (anti-Ki-67) identified areas of disease progression at both fluence rates after PDT. However, increased EGFR activation in proliferative areas was detected only after treatment at the higher fluence rate of 150 mW/cm. These data suggest that fluence rate may affect the activation of survival factors, such as EGFR, and weaker activation at lower fluence rate could contribute to a smaller tumor burden after PDT at 75 mW/cm. 相似文献
955.
956.
Sébastien G. Gouin Dr. Adinda Wellens Julie Bouckaert Dr. José Kovensky Prof. 《ChemMedChem》2009,4(5):749-755
Sweet medicine : Multimeric glycoconjugates with valencies ranging from one to four were synthesized by click chemistry. Unprecedented adhesion inhibitions of piliated E. coli to human bladder cells were recorded with the multimers; a tetravalent derivative showed inhibitory concentrations 6000‐ and 64‐fold lower than mannose and heptyl α‐D ‐mannoside, respectively.
957.
Kelvin Y. Xie Sachin Shrestha Yang Cao Peter J. Felfer Yanbo Wang Xiaozhou Liao Julie M. Cairney Simon P. Ringer 《Acta Materialia》2013,61(2):439-452
The effects of two types of pre-existing defects, dislocations and clusters, on the strength and deformation behavior of body-centered cubic Fe nanopillars with a diameter of ~150 nm were investigated using in situ nanocompression in a transmission electron microscope. The plastic deformation of nanopillars containing high initial dislocation densities was observed to be relatively continuous, proceeding via a series of small- and intermediate-scale strain bursts that were associated with the movement/escape of dislocations and the formation of slip bands. Mechanical annealing was observed in nanopillars with high dislocation densities. When the dislocation density was reduced by in situ heating, the nanopillars were much stronger and the plastic deformation behavior transformed to a more abrupt and explosive mode. The introduction of a dispersion of solute atom clusters into nanopillars caused further strengthening as a higher stress level is required for dislocations to pass the clusters. The strengthening effect of cluster dispersion in nanopillars is comparable to that observed in the bulk steel. These phenomena are universal for Fe nanopillars with different crystallographic orientations. 相似文献
958.
959.
Imalka H. A. M. Arachchilage Joseph Basi Shahedul Islam Julie P. Harmon 《Polymer Engineering and Science》2021,61(3):680-692
Development of polyurethanes (PU) has come a long way from their origin in 1937 and has unique applications in a diverse set of fields. Recent PU developments are focusing more on the naturally-derived diols in the synthesis process in an effort to make them more environmentally friendly. In this study, three different diisocyanates (aliphatic, cycloaliphatic, and aromatic diisocyanates) were combined with laccol, which extracted from Vietnamese lacquer sap (Toxicodendron succedanea) to synthesize novel PUs. Influence of the different diisocyanates in novel PUs, hydrogen bonding capability, and crosslinking ability were investigated to provide a broader characteristic scope for future developments. Resulting materials illustrated good thermal stability after exposed to higher temperatures and the hydrogen bonding regions corresponding to N H (3326 cm−1) and CO (1652 cm−1) groups were shifted to higher wavenumber according to Fourier transform infra-red spectroscopy analysis. Further curing occurred with temperature treatment and improved the overall quality of novel PUs. Powder X-ray analysis, micro hardness, and swelling analysis were utilized to identify molecular packing and crosslinking effects. Higher crosslink density observed for cycloaliphatic and aromatic diisocyanate incorporated novel polyurethanes compared to aliphatic diisocyanate incorporated polyurethane. 相似文献
960.
Claire Mével Julie Carreaud Gaëlle Delaizir Jean-René Duclère François Brisset Julie Bourret Pierre Carles Cécile Genevois Mathieu Allix Sébastien Chenu 《Journal of the European Ceramic Society》2021,41(9):4934-4941
Transparent polycrystalline ZnGa2O4 ceramics are synthesized, for the first time, by combining high-energy ball milling, solid-state reaction and spark plasma sintering. They appear transparent in both the visible and near infrared (up to 9 μm) ranges after a post-SPS annealing in air converting the raw semiconductor into an electrical insulator. The maximum of transmittance is reached in the near infrared region, at around 2.5 μm, with a value of 78 % (1 mm thick sample) close to the maximum value of transmittance previously measured for single crystals. These transparent ceramics present a classic cubic spinel ZnGa2O4 structure and a dense microstructure (> 99 %) attained without sintering aids, with an average grain size of 600 nm and a random orientation of the crystallites. TEM observations performed on thin foils have revealed limited nanometer scale intergranular porosity which does not affect much the transparency. As a proof of interest, red long-lasting luminescence arising from the entire sample volume is observed in these Cr3+ doped transparent ceramics. This innovative work is anticipated to further drive the development of transparent ZnGa2O4 ceramics towards a wider range of performing optical applications such as laser emission. 相似文献