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排序方式: 共有355条查询结果,搜索用时 15 毫秒
91.
Stefano Montanelli Devis Bianchini Carola Aiello Roberto Baldoni Cristiana Bolchini Silvia Bonomi Silvana Castano Tiziana Catarci Valeria De Antonellis Alfio Ferrara Michele Melchiori Elisa Quintarelli Monica Scannapieco Fabio A. Schreiber Letizia Tanca 《Journal of Intelligent Information Systems》2011,36(2):167-195
In this paper, we present Esteem (Emergent Semantics and cooperaTion in multi-knowledgE EnvironMents), a community-based P2P platform for supporting semantic collaboration among a set of independent peers, without prior reciprocal knowledge and no predefined relationships. Goal of Esteem is to go beyond the existing state-of-the-art solutions for P2P knowledge sharing and to provide an integrated platform for both data and service discovery. A distinguishing feature of Esteem is the use of semantic communities to explicitly give shape to the collective knowledge and expertise of peer groups with similar interests. Key techniques of Esteem will be presented in the paper and concern: shuffling-based communication, ontology and service matchmaking, context management, and quality-aware data integration. An application example of data and service discovery in the health-care domain will be presented, by also discussing results of system and user evaluation. 相似文献
92.
Luca Fambri Izabela Dabrowska Giuseppe Ferrara Alessandro Pegoretti 《Polymer Composites》2016,37(1):288-298
Viscoelastic properties of nanocomposite fibers of high density polyethylene (HDPE) and organically modified hydrotalcite were studied. Neat and nanofilled HDPE fibers (with nanofiller content between 0.5 and 3 wt%) were produced by melt spinning and hot‐drawing at different draw ratios up to 20. Effect of temperature on storage modulus, loss modulus, and creep compliance were compared. Rising nanofiller content and/or drawing ratio accounted for an increase in storage modulus in the glassy (i.e., below the γ transition at −100°C) as well as in the rubbery state of non‐crystalline regions. The α relaxation temperature read‐off for the maximum of the loss modulus peak ranged from 20 to 60°C being dependent on frequency, filler content and draw ratio. Sumita model was successfully applied to evaluate the effective volume fraction of the dispersed phase; maximum fraction of immobilized matrix was observed for the composite with 1 wt% of nanofiller. Creep behavior was evaluated by fitting experimental data with the Burgers model. The addition of a small amount of well‐dispersed hydrotalcite (0.5–1 wt%) had a beneficial effect on the creep resistance of drawn fibers at room temperature as well as at 70°C. TEM analysis evidenced a good dispersion of 0.5% nanofiller in as‐spun fibers and improved interfacial adhesion after drawing. The best mechanical properties were observed for the composition with 1 wt% of hydrotalcite, due to combined effects of nanofiller reinforcement and stiffening produced by hot drawing. POLYM. COMPOS., 288–298, 2016. © 2014 Society of Plastics Engineers 相似文献
93.
Kruse DE Silverman RH Fornaris RJ Coleman DJ Ferrara KW 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1998,45(6):1437-1440
In contrast to previous systems in which an ultrasonic pulse was repeatedly directed to a discrete line of sight, a new method has been developed to continuously scan over a region in order to rapidly assess blood velocities in superficial small blood vessels. Using this technique, which we call swept-scan, a high frequency transducer can rapidly translate across a region of interest, and sensitive maps of blood velocity in small blood vessels can be constructed. This system has been applied to flow mapping in the anterior segment of the eye, which is clinically significant in cases of trauma and glaucoma. No previous imaging technique has been capable of estimating blood velocities within this region in a clinically useful manner. With this new technique, each 2-D scan of the eye can be obtained in an interval on the order of 1 second, and blood flow through the iris and ciliary body can be detected in vessels as small as 40 microns. A major implication of this new technique is that a wall filter can be applied continuously to the return from all regions, thus eliminating the transient response that occurs along each line of sight in traditional Doppler systems. 相似文献
94.
Patel DN Bloch SH Dayton PA Ferrara KW 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(3):293-301
Previous studies have revealed that hard-shelled submicron contrast agents exhibit large relative expansions and strong acoustical echoes that can be observed experimentally, and predicted by theoretical simulations. In this paper, we study harmonic imaging and pulse-pair imaging techniques designed to assist in the differentiation of these contrast agents from tissue. For harmonic imaging, we apply a high-sensitivity, narrowband strategy that differentiates the microbubble from tissue based on the generation of strong harmonic echoes. For pulse-pair imaging, we apply high spatial resolution, wideband strategies using phase inversion, which relies on the frequency differences observed in response to phase-inverted pulses, and signal subtraction, which takes advantage of the amplitude differences in response to identical pulses. The bubble-to-phantom signal amplitude ratio in the absence of motion approaches 20 dB using phase inversion and 30 dB using signal subtraction; both techniques are robust for up to 50 microm of simulated motion. With the experience gained in these studies, we hope to advance the development of multi-pulse or shaped-pulse techniques that are optimized for specific clinical applications. 相似文献
95.
Eric Bardenhagen Giulio Senes Susan Rodiek Cristina Ferrara Adeleh Nejati Natalia Fumagalli 《Landscape Research》2013,38(6):688-701
To test applicability of an environmental assessment instrument in new settings, the ratings and reliability of the SOS Tool were compared in diverse settings with a similar climate: Milan, Italy; and Bryan/College Station, Texas, USA. This instrument evaluates physical environment support for outdoor usage by residents at senior facilities. Two trained raters assigned ratings (using a 1–7 scale) to the 60 instrument items at each setting (Italy: 94 outdoor spaces, 67 facilities; US: 22 outdoor spaces, 12 facilities). Overall mean ratings were similar across both sites (6% difference), and three of the five domains had comparable mean ratings. Mean inter-rater reliability was good in both settings but higher in Italy (ICC = .97 versus .82). Despite geographic/cultural differences, mean ratings for most items and domains were surprisingly similar between Italy and the US. This finding, and the high inter-rater reliability found in both settings, suggest this instrument may be useful in a wide range of settings. 相似文献
96.
Liberato Ferrara Massimiliano Cremonesi Nathan Tregger Attilio Frangi Surendra P. Shah 《Cement and Concrete Research》2012,42(8):1134-1146
Cementitious composites with customized rheologies are becoming increasingly popular throughout a wide variety of civil engineering applications. Assessing their fundamental rheological properties is crucial for the success of a particular application. Their measurement is not a trivial task and typically requires dedicated and expensive equipment. These equipment may not be compatible with field applications and not even available in every laboratory. Correlations between fundamental rheological properties and field test measurements have been assessed, as for the yield stress versus the slump flow diameter. As for the plastic viscosity, different attempts have been made, with flow time parameters measured from different tests. This work provides further evidence to the aforementioned correlations, with reference to a broad range of cement pastes and mortars formulated from SCCs, as well as employing a tool for Computational Fluid Dynamics (CFD) modeling developed by the authors. 相似文献
97.
Laura Micheli Samuele Maramai Alessandra Toti Valentina Ferrara Clara Ciampi Lorenzo Di Cesare Mannelli Carla Ghelardini 《International journal of molecular sciences》2022,23(15)
Neuroinflammation is a key pathological event shared by different diseases affecting the nervous system. Since the underlying mechanism of neuroinflammation is a complex and multifaceted process, current pharmacological treatments are unsatisfactory—a reason why new therapeutic approaches are mandatory. In this context, the endocannabinoid system has proven to possess neuroprotective and immunomodulatory actions under neuroinflammatory status, and its modulation could represent a valuable approach to address different inflammatory processes. To this aim, we evaluated the efficacy of a repeated treatment with NSD1819, a potent β-lactam-based monoacylglycerol lipase inhibitor in a mouse model of neuroinflammation induced by lipopolysaccharide (LPS) injection. Mice were intraperitoneally injected with LPS 1 mg/kg for five consecutive days to induce systemic inflammation. Concurrently, NSD1819 (3 mg/kg) was daily per os administered from day 1 until the end of the experiment (day 11). Starting from day 8, behavioral measurements were performed to evaluate the effect of the treatment on cognitive impairments, allodynia, motor alterations, anhedonia, and depressive-like behaviors evoked by LPS. Histologically, glial analysis of the spinal cord was also performed. The administration of NSD1819 was able to completely counteract thermal and mechanical allodynia as highlighted by the Cold plate and von Frey tests, respectively, and to reduce motor impairments as demonstrated by the Rota rod test. Moreover, the compound was capable of neutralizing the memory loss in the Passive avoidance test, and reducing depressive-like behavior in the Porsolt test. Finally, LPS stimulation caused a significant glial cells activation in the dorsal horn of the lumbar spinal cord that was significantly recovered by NSD1819 repeated treatment. In conclusion, NSD1819 was able to thwart the plethora of symptoms evoked by LPS, thus representing a promising candidate for future applications in the context of neuroinflammation and related diseases. 相似文献
98.
Benedetta Ferrara Erica Dugnani Valeria Sordi Valentina Pasquale Silvia Pellegrini Michele Reni Gianpaolo Balzano Lorenzo Piemonti 《International journal of molecular sciences》2022,23(18)
The aim of this study is to provide a comprehensive characterization of stemness in pancreatic ductal adenocarcinoma (PDAC) cell lines. Seventeen cell lines were evaluated for the expression of cancer stem cell (CSC) markers. The two putative pancreatic CSC phenotypes were expressed heterogeneously ranging from 0 to 99.35% (median 3.46) for ESA+CD24+CD44+ and 0 to 1.94% (median 0.13) for CXCR4+CD133+. Cell lines were classified according to ESA+CD24+CD44+ expression as: Low-Stemness (LS; <5%, n = 9, median 0.31%); Medium-Stemness (MS; 6–20%, n = 4, median 12.4%); and High-Stemness (HS; >20%, n = 4, median 95.8%) cell lines. Higher degree of stemness was associated with in vivo tumorigenicity but not with in vitro growth kinetics, clonogenicity, and chemo-resistance. A wide characterization (chemokine receptors, factors involved in pancreatic organogenesis, markers of epithelial–mesenchymal transition, and secretome) revealed that the degree of stemness was associated with KRT19 and NKX2.2 mRNA expression, with CD49a and CA19.9/Tie2 protein expression, and with the secretion of VEGF, IL-7, IL-12p70, IL-6, CCL3, IL-10, and CXCL9. The expression of stem cell markers was also evaluated on primary tumor cells from 55 PDAC patients who underwent pancreatectomy with radical intent, revealing that CXCR4+/CD133+ and CD24+ cells, but not ESA+CD24+CD44+, are independent predictors of mortality. 相似文献
99.
A Ferrara E Barrett-Connor DL Wingard SL Edelstein 《Canadian Metallurgical Quarterly》1995,18(2):220-225
OBJECTIVE--To determine if insulin levels vary with sex, independent of estrogen replacement therapy (ERT), differences in body mass index (BMI), waist-to-hip ratio (WHR), and glycemia. RESEARCH DESIGN AND METHODS--In a population-based study of older adults, insulin levels were measured before and after a standardized oral glucose tolerance test in 673 men and 849 women, all free of known diabetes. RESULTS--Age-adjusted fasting insulin levels were highest in men, intermediate in women not taking estrogen, and lowest in estrogen-treated women (P < 0.01). Differences between men and women not taking estrogen disappeared after adjusting for age and BMI, but not glycemia; estrogen-treated women had significantly lower fasting insulin levels than did men (P < 0.01) and women not taking estrogen (P < 0.01). The association of estrogen use with lower fasting insulin levels persisted after adjusting for age and WHR (P < 0.001) and was stronger among women with abnormal glucose tolerance. Age-adjusted postchallenge insulin levels were higher in women than in men (P < 0.01). The sex difference persisted after adjusting for age and BMI or glycemia. Postchallenge insulin levels did not vary by ERT. CONCLUSIONS--Men have higher fasting insulin levels than do women, whether or not the women are using ERT. Differences between men and untreated women are explained by differences in BMI, but estrogen users have lower fasting insulin levels independent of BMI. Postchallenge insulin levels are higher in women than men and are independent of ERT, BMI, and glycemia. Clinical trials in women are needed to determine whether ERT can improve insulin and glucose metabolism. 相似文献
100.
Giulia Ferrara Antonio Salvaggio Roberta Pecoraro Elena Maria Scalisi Andrea Maria Presti Giuliana Impellizzeri Maria Violetta Brundo 《Microscopy research and technique》2020,83(4):332-337
The aim of this study was to evaluate the toxicity of titanium dioxide nanoparticles (TiO2NPs) by short‐term toxicity tests in Apis mellifera, considered an excellent bioindicator organism mainly due to its sensitivity. Bees have been exposed to several concentrations of TiO2NPs (1 × 10?3, 1 × 10?4, 1 × 10?5, 1 × 10?6 mg/10 ml) for 10 days. Morphostructural and histological assays were done on gut and honey sac. The research of exposure biomarkers like metallothioneins 1 (MT1) and Heat Shock Protein 70 (HSP70) was performed to verify if a detoxification mechanism has been activated in the exposed animals. No histological alteration on the epithelium of the gut and honey sac were observed in exposed samples. A significant positivity for anti‐MT1 antibody was observed only in the honey sac cells. A weak positivity for HSP70 was observed in both structures analyzed. In several studies have shown the non‐toxicity of TiO2NPs on other model organisms, in our study, titanium dioxide nanoparticles was proven to be highly toxic at the highest concentration tested (100% of lethality to 1 × 10?3 mg/10 ml) and moderately toxic at lower concentrations. Honey bees proved to be excellent models for study of NPs toxicity and for monitoring environment. 相似文献