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排序方式: 共有287条查询结果,搜索用时 15 毫秒
1.
A. Mandrino R. Eloy B. Moyen J. L. Lerat D. Treheux 《Journal of materials science. Materials in medicine》1992,3(6):457-463
Base alumina ceramics with dispersoids (BAC) are a new class of ceramics with improved mechanical properties as compared to pure alumina. They are obtained by dispersion of powder within an alumina matrix. Of the three new ceramics studied here, A20Z possesses the best mechanical properties as well as tribological properties superior to those of pure alumina whether it is used in ceramic-ceramic or ceramic-polyethylene combination.Mechanical behaviour and tissue response afterin vivo implantation were studied. Small four-point flexion bars obtained by pressureless sintering were implanted subcutaneously in the rat. The mechanical properties were unmodified even after one year from implantation.The tissue response was studied up to one year on cylinders implanted in the paravertebral muscles of Wistar rats, and was evaluated by qualitative examination of the encapsulating membrane and measurement of its thickness in relation to pure alumina. The tissue responses were comparable for both alumina and the three tested ceramics. 相似文献
2.
The partial oxidation of methane over the supported Rh (0.8 wt.%) catalysts was investigated. Two kinds of supports were used, MgO and Ti-modified MgO (prepared by grafting technique). Among the Ti-modified MgO supports, two different compounds were used as source of Ti: inorganic (chloride) and organic (alkoxide). The catalytic performance of Rh-supported catalysts depends on the support and varies in the sequence: Ti-MgO/I > Ti-MgO/O > MgO. Ti-containing catalysts exhibited higher activity and selectivity compared to MgO, which is especially noticeable at low temperature. Possible explanations for the phenomena observed were proposed on the basis of characterization results. 相似文献
3.
Wenbo Zhou Julia Craft Alex Ojemann Luke Bergen Arin Graner Aitana Gonzales Qianbin He Timothy Kopper Marie Smith Michael W. Graner Xiaoli Yu 《International journal of molecular sciences》2022,23(13)
WHO Grade 4 IDH-wild type astrocytoma (GBM) is the deadliest brain tumor with a poor prognosis. Meningioma (MMA) is a more common “benign” central nervous system tumor but with significant recurrence rates. There is an urgent need for brain tumor biomarkers for early diagnosis and effective treatment options. Extracellular vesicles (EVs) are tiny membrane-enclosed vesicles that play essential functions in cell-to-cell communications among tumor cells. We aimed to identify epitopes of brain tumor EVs by phage peptide libraries. EVs from GBM plasma, MMA plasma, or brain tumor cell lines were used to screen phage-displayed random peptide libraries to identify high-affinity peptides. We purified EVs from three GBM plasma pools (23 patients), one MMA pool (10 patients), and four brain tumor cell lines. We identified a total of 21 high-affinity phage peptides (12 unique) specific to brain tumor EVs. The peptides shared high sequence homologies among those selected by the same EVs. Dose–response ELISA demonstrated that phage peptides were specific to brain tumor EVs compared to controls. Peptide affinity purification identified unique brain tumor EV subpopulations. Significantly, GBM EV peptides inhibit brain tumor EV-induced complement-dependent cytotoxicity (necrosis) in neurons. We conclude that phage display technology could identify specific peptides to isolate and characterize tumor EVs. 相似文献
4.
Kay-Arne Walther Jos Roberto Gonzales Sabine Grger Benjamin Ehmke Dogan Kaner Katrin Lorenz Peter Eickholz Thomas Kocher Ti-Sun Kim Ulrich Schlagenhauf Raphael Koch Jrg Meyle 《International journal of molecular sciences》2022,23(13)
Periodontitis is a multifactorial disease. The aim of this explorative study was to investigate the role of Interleukin-(IL)-1, IL-4, GATA-3 and Cyclooxygenase-(COX)-2 polymorphisms after non-surgical periodontal therapy with adjunctive systemic antibiotics (amoxicillin/metronidazole) and subsequent maintenance in a Caucasian population. Analyses were performed using blood samples from periodontitis patients of a multi-center trial (ClinicalTrials.gov =ABPARO-study). Polymorphisms were analyzed using quantitative real-time PCR. Clinical attachment levels (CAL), percentage of sites showing further attachment loss (PSAL) ≥1.3 mm, bleeding on probing (BOP) and plaque score were assessed. Exploratory statistical analysis was performed. A total of 209 samples were genotyped. Patients carrying heterozygous genotypes and single-nucleotide-polymorphisms (SNP) on the GATA-3-IVS4 +1468 gene locus showed less CAL loss than patients carrying wild type. Heterozygous genotypes and SNPs on the IL-1A-889, IL-1B +3954, IL-4-34, IL-4-590, GATA-3-IVS4 +1468 and COX-2-1195 gene loci did not influence CAL. In multivariate analysis, CAL was lower in patients carrying GATA-3 heterozygous genotypes and SNPs than those carrying wild-types. For the first time, effects of different genotypes were analyzed in periodontitis progression after periodontal therapy and during supportive treatment using systemic antibiotics demonstrating a slight association of GATA-3 gene locus with CAL. This result suggests that GATA-3 genotypes are a contributory but non-essential risk factor for periodontal disease progression. NCT00707369相似文献
5.
Mariano Cabezas Arnau Oliver Eloy Roura Jordi Freixenet Joan C. Vilanova Lluís Ramió-Torrentà Àlex Rovira Xavier Lladó 《Computer methods and programs in biomedicine》2014
Magnetic resonance imaging (MRI) is frequently used to detect and segment multiple sclerosis lesions due to the detailed and rich information provided. We present a modified expectation-maximisation algorithm to segment brain tissues (white matter, grey matter, and cerebro-spinal fluid) as well as a partial volume class containing fluid and grey matter. This algorithm provides an initial segmentation in which lesions are not separated from tissue, thus a second step is needed to find them. This second step involves the thresholding of the FLAIR image, followed by a regionwise refinement to discard false detections. To evaluate the proposal, we used a database with 45 cases comprising 1.5T imaging data from three different hospitals with different scanner machines and with a variable lesion load per case. The results for our database point out to a higher accuracy when compared to two of the best state-of-the-art approaches. 相似文献
6.
Wanderson Gonalves e Gonalves Marcelo Henrique Paula dos Santos Leonardo Miranda Brito Helber Gonzales Almeida Palheta Fbio Manoel Frana Lobato Samia Demachki ndrea Ribeiro-dos-Santos Gilderlanio Santana de Araújo 《International journal of molecular sciences》2022,23(23)
Emerging deep learning-based applications in precision medicine include computational histopathological analysis. However, there is a lack of the required training image datasets to generate classification and detection models. This phenomenon occurs mainly due to human factors that make it difficult to obtain well-annotated data. The present study provides a curated public collection of histopathological images (DeepHP) and a convolutional neural network model for diagnosing gastritis. Images from gastric biopsy histopathological exams were used to investigate the performance of the proposed model in detecting gastric mucosa with Helicobacter pylori infection. The DeepHP database comprises 394,926 histopathological images, of which 111 K were labeled as Helicobacter pylori positive and 283 K were Helicobacter pylori negative. We investigated the classification performance of three Convolutional Neural Network architectures. The models were tested and validated with two distinct image sets of 15% (59K patches) chosen randomly. The VGG16 architecture showed the best results with an Area Under the Curve of 0.998%. The results showed that CNN could be used to classify histopathological images from gastric mucosa with marked precision. Our model evidenced high potential and application in the computational pathology field. 相似文献
7.
Synthetic and Biological Studies of Sesquiterpene Polygodial: Activity of 9‐Epipolygodial against Drug‐Resistant Cancer Cells 下载免费PDF全文
Dr. Ramesh Dasari Annelise De Carvalho Derek C. Medellin Kelsey N. Middleton Dr. Frédéric Hague Marie N. M. Volmar Prof. Liliya V. Frolova Dr. Mateus F. Rossato Jorge J. De La Chapa Nicholas F. Dybdal‐Hargreaves Akshita Pillai Prof. Véronique Mathieu Prof. Snezna Rogelj Prof. Cara B. Gonzales Prof. João B. Calixto Prof. Antonio Evidente Dr. Mathieu Gautier Dr. Gnanasekar Munirathinam Prof. Rainer Glass Prof. Patricia Burth Dr. Stephen C. Pelly Prof. Willem A. L. van Otterlo Prof. Robert Kiss Prof. Alexander Kornienko 《ChemMedChem》2015,10(12):2014-2026
Polygodial, a terpenoid dialdehyde isolated from Polygonum hydropiper L., is a known agonist of the transient receptor potential vanilloid 1 (TRPV1). In this investigation a series of polygodial analogues were prepared and investigated for TRPV1‐agonist and anticancer activities. These experiments led to the identification of 9‐epipolygodial, which has antiproliferative potency significantly exceeding that of polygodial. 9‐Epipolygodial was found to maintain potency against apoptosis‐resistant cancer cells as well as those displaying the multidrug‐resistant (MDR) phenotype. In addition, the chemical feasibility for the previously proposed mechanism of action of polygodial, involving the formation of a Paal–Knorr pyrrole with a lysine residue on the target protein, was demonstrated by the synthesis of a stable polygodial pyrrole derivative. These studies reveal rich chemical and biological properties associated with polygodial and its direct derivatives. These compounds should inspire further work in this area aimed at the development of new pharmacological agents, or the exploration of novel mechanisms of covalent modification of biological molecules with natural products. 相似文献
8.
R. Delaigle M. M. F. Joseph D. P. Debecker P. Eloy E. M. Gaigneaux 《Topics in Catalysis》2013,56(18-20):1867-1874
An alternative way of synthesis, the “onion” method, was used to deposit silver nanoparticles on a VOx/TiO2 catalyst. This synthesis method consists in the impregnation of organic vesicles containing the metallic silver nanoparticles. In situ calcination is needed to remove the organic vesicles and to offer an access of the reactants to the silver nanoparticles. This removal is easier in presence of vanadium. The addition of silver induces a higher proportion of V5+. The Ag-VOx/TiO2 catalysts prepared with this method exhibit better performances in the total oxidation of benzene after moderate in situ calcination at 350 °C than at 450 °C. A synergy between silver and vanadium is evidenced after both kinds of calcination with a silver loading of 0.125 and 0.25 wt%. The extent of this synergy is higher after a moderate calcination. This effect is likely due to the fact that small nanoparticles prepared via the “onions” sinter less after in situ calcination at 350 °C than at 450 °C. A clear link between the extent of the synergy and the size of the silver nanoparticles is evidenced. A decrease of the nanoparticle size induces a higher extent for the synergy. 相似文献
9.
Andr Luís Muller Eurípedes do Amaral Vargas Jr. Luiz Eloy Vaz Clemente Jos Gonalves 《Journal of Petroleum Science and Engineering》2009,68(3-4):268-276
In general, analysis of oil producing wells is carried out considering that both hydraulic and mechanical parameters of the rock mass are deterministic. Mechanical and hydraulic properties of rock masses and in particular sedimentary rock masses may show a considerable degree of spatial variability. This paper focuses on the evaluation of the three-dimensional borehole response, particularly of the plastic zone, taking into account the spatial variability of both hydraulic and mechanical properties. The analysis is performed with a developed finite element program that incorporates spatial variability, coupled fluid-mechanical effects and elastoplastic behavior of the rock mass. Examples are shown and conclusions are drawn regarding the effect of spatial variability on the three-dimensional borehole analysis. 相似文献
10.