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排序方式: 共有1380条查询结果,搜索用时 15 毫秒
121.
Abstract An empirical electrical equivalent circuit for dielectric thin films, based on experimental data, is developed. Current responses to voltage-steps and to voltage-ramps are calculated and compared with experimental data. The simulation allows us to separate current contributions of different physical processes while the experiment only reveals the sum of the currents. 相似文献
122.
Kampf Thomas Sturm Volker J. F. Basse-Lüsebrink Thomas C. Fischer André Buschle Lukas R. Kurz Felix T. Schlemmer Heinz-Peter Ziener Christian H. Heiland Sabine Bendszus Martin Pham Mirko Stoll Guido Jakob Peter M. 《Magma (New York, N.Y.)》2019,32(1):63-77
Magnetic Resonance Materials in Physics, Biology and Medicine - In magnetic resonance imaging (MRI), compressed sensing (CS) enables the reconstruction of undersampled sparse data sets. Thus,... 相似文献
123.
Guido H. Jajamovich Wei Huang Cecilia Besa Xin Li Aneela Afzal Hadrien A. Dyvorne Bachir Taouli 《Magma (New York, N.Y.)》2016,29(1):49-58
Objective
To quantify hepatocellular carcinoma (HCC) perfusion and flow with the fast exchange regime-allowed Shutter-Speed model (SSM) compared to the Tofts model (TM).Materials and methods
In this prospective study, 25 patients with HCC underwent DCE-MRI. ROIs were placed in liver parenchyma, portal vein, aorta and HCC lesions. Signal intensities were analyzed employing dual-input TM and SSM models. ART (arterial fraction), K trans (contrast agent transfer rate constant from plasma to extravascular extracellular space), v e (extravascular extracellular volume fraction), k ep (contrast agent intravasation rate constant), and τ i (mean intracellular water molecule lifetime) were compared between liver parenchyma and HCC, and ART, K trans, v e and k ep were compared between models using Wilcoxon tests and limits of agreement. Test–retest reproducibility was assessed in 10 patients.Results
ART and v e obtained with TM; ART, v e , k e and τ i obtained with SSM were significantly different between liver parenchyma and HCC (p < 0.04). Parameters showed variable reproducibility (CV range 14.7–66.5 % for both models). Liver K trans and v e ; HCC v e and k ep were significantly different when estimated with the two models (p < 0.03).Conclusion
Our results show differences when computed between the TM and the SSM. However, these differences are smaller than parameter reproducibilities and may be of limited clinical significance.124.
Daniela Lisini Sara Lettieri Sara Nava Giulia Accordino Simona Frigerio Chandra Bortolotto Andrea Lancia Andrea Riccardo Filippi Francesco Agustoni Laura Pandolfi Davide Piloni Patrizia Comoli Angelo Guido Corsico Giulia Maria Stella 《International journal of molecular sciences》2021,22(16)
Malignant Pleural Mesothelioma (MPM) is a rare and aggressive neoplasm of the pleural mesothelium, mainly associated with asbestos exposure and still lacking effective therapies. Modern targeted biological strategies that have revolutionized the therapy of other solid tumors have not had success so far in the MPM. Combination immunotherapy might achieve better results over chemotherapy alone, but there is still a need for more effective therapeutic approaches. Based on the peculiar disease features of MPM, several strategies for local therapeutic delivery have been developed over the past years. The common rationale of these approaches is: (i) to reduce the risk of drug inactivation before reaching the target tumor cells; (ii) to increase the concentration of active drugs in the tumor micro-environment and their bioavailability; (iii) to reduce toxic effects on normal, non-transformed cells, because of much lower drug doses than those used for systemic chemotherapy. The complex interactions between drugs and the local immune-inflammatory micro-environment modulate the subsequent clinical response. In this perspective, the main interest is currently addressed to the development of local drug delivery platforms, both cell therapy and engineered nanotools. We here propose a review aimed at deep investigation of the biologic effects of the current local therapies for MPM, including cell therapies, and the mechanisms of interaction with the tumor micro-environment. 相似文献
125.
Debora?FinoEmail author Paolo?Fino Guido?Saracco Vito?Specchia 《Korean Journal of Chemical Engineering》2003,20(3):445-450
The development of catalytic means for the regeneration of particulate-laden traps for diesel exhaust cleaning is the main
topic of this paper. All the steps of the catalytic trap preparation are dealt with, including: the synthesis and choice of
the proper catalyst and trap materials, the development ofin situ catalyst deposition, and the bench testing of the derived catalytic traps. Two different traps were considered (i.e., silicon
carbide and cordierite wallflow monoliths operating via a shallow-bed filtration mechanism), whereas the best catalyst selected
was the perovskite LaCr0.9O3. The filtration efficiency and the pressure drops of the catalytic and non-catalytic monoliths were evaluated on a diesel
engine bench under various operating conditions. On the basis of the obtained results the catalysed SiC converter was found
to be the most satisfactory converter to be placed on the exhaust line of the modern common rail diesel-engine cars. 相似文献
126.
Guido Busca 《Catalysis Today》1996,27(3-4):457-496
The use of IR spectroscopic techniques to provide information on the mechanisms of catalytic oxidation over metal oxide catalysts is briefly discussed. The data published on studies of the catalytic oxidation of methanol, of linear C4 hydrocarbons and of methylaromatics over different metal oxide surfaces are reviewed and discussed. Lattice oxygen appears to act as the active oxygen species in both selective and total oxidation. Generalized mechanisms of these complex oxidation reactions are proposed and the catalyst features affecting selectivities in these reactions are discussed. The reaction network is apparently essentially governed by the organic chemistry of the reacting molecule (thus being substantially the same over the different oxide catalysts). However, the catalyst surface governs the rate of the different steps, favoring some paths over others. Thus, selectivity is determined by the catalyst chemical behavior and by the reaction variables (contact time, temperature, gas-phase composition, presence of steam, etc.). IR studies, if performed under conditions where some intermediates are actually detectable and jointly with other techniques, can give valuable information on the catalysis mechanisms. On the other hand, it has been concluded that in situ studies frequently do not give reliable information on reaction mechanisms, because under reaction conditions spectators rather than intermediates are detected. 相似文献
127.
The Expression of Lipoprotein Receptors Is Increased in the Infarcted Area After Myocardial Infarction Induced in Rats With Cardiac Dysfunction 下载免费PDF全文
Aline D. de Lima Maria C. Guido Elaine R. Tavares Priscila O. Carvalho Alyne F. Marques Marcelo D. T. de Melo Vera M. C. Salemi Roberto Kalil‐Filho Raul C. Maranhão 《Lipids》2018,53(2):177-187
Left ventricular (LV) remodeling after myocardial infarction constitutes the structural basis for ventricular dysfunction and heart failure. The characterization underlying the expression of lipoprotein receptors in cardiac dysfunction is scarcely explored. The aim of this study was to analyze the status of lipoprotein receptors on the infarcted and noninfarcted areas of LV and to verify whether nanoparticles that mimic the lipid structure of low‐density lipoprotein (LDL) and have the ability to bind to LDL receptors (LDE) are taken up more avidly by the noninfarcted LV. 13 male Wistar rats with left coronary artery ligation (myocardial infarction [MI]) and 12 animals with SHAM operation (SHAM) were used in this study. 6 weeks after the procedure, the quantification of low‐density lipoprotein receptor (LDLR), LDL receptor‐related protein 1 (LRP1), scavenger receptor‐class B type I (SR‐BI) lipoprotein receptors, and PCNA proliferation marker, and tissue uptake of radioactively labeled LDE were performed. Immunohistochemistry and Western blot analysis showed that LDLR, LRP1, SR‐BI, and PCNA, expression in infarcted area of MI was remarkably higher than SHAM and noninfarcted subendocardial (SEN) and interstitial (INT) areas. In addition, in SEN noninfarcted area of MI, the presence of LDLR was about threefold higher than in SHAM SEN and INT noninfarcted areas. The LDE uptake of noninfarcted LV of MI group was about 30% greater than that of SHAM group. In conclusion, these findings regarding the status of lipoprotein receptors after MI induction could help to establish mechanisms on myocardial repairing. In conclusion, infarcted rats with LV dysfunction showed increased expression of lipoprotein receptors mainly in the infarcted area. 相似文献
128.
Targeting Serotonin 2A and Adrenergic α1 Receptors for Ocular Antihypertensive Agents: Discovery of 3,4‐Dihydropyrazino[1,2‐b]indazol‐1(2H)‐one Derivatives 下载免费PDF全文
Dr. Guido Furlotti Dr. Maria Alessandra Alisi Dr. Nicola Cazzolla Dr. Francesca Ceccacci Dr. Beatrice Garrone Dr. Tecla Gasperi Dr. Angela La Bella Prof. Dr. Francesca Leonelli Prof. Dr. Maria Antonietta Loreto Dr. Gabriele Magarò Giorgina Mangano Prof. Dr. Rinaldo Marini Bettolo Dr. Emanuela Masini Dr. Martina Miceli Dr. Luisa Maria Migneco Dr. Marco Vitiello 《ChemMedChem》2018,13(15):1597-1607
Glaucoma affects millions of people worldwide and causes optic nerve damage and blindness. The elevation of the intraocular pressure (IOP) is the main risk factor associated with this pathology, and decreasing IOP is the key therapeutic target of current pharmacological treatments. As potential ocular hypotensive agents, we studied compounds that act on two receptors (serotonin 2A and adrenergic α1) linked to the regulation of aqueous humour dynamics. Herein we describe the design, synthesis, and pharmacological profiling of a series of novel bicyclic and tricyclic N2‐alkyl‐indazole‐amide derivatives. This study identified a 3,4‐dihydropyrazino[1,2‐b]indazol‐1(2H)‐one derivative with potent serotonin 2A receptor antagonism, >100‐fold selectivity over other serotonin subtype receptors, and high affinity for the α1 receptor. Moreover, upon local administration, this compound showed superior ocular hypotensive action in vivo relative to the clinically used reference compound timolol. 相似文献
129.
130.
Summary. In this paper we introduce and analyze two new cost measures related to the communication overhead and the space requirements
associated with virtual path layouts in ATM networks, that is the edge congestion and the node congestion. Informally, the edge congestion of a given edge e at an incident node u is defined as the number of VPs terminating at or starting from u and using e, while the node congestion of a node v is defined as the number of VPs having v as an endpoint. We investigate the problem of constructing virtual path layouts allowing to connect a specified root node
to all the others in at most h hops and with maximum edge or node congestion c, for two given integers h and c. We first give tight results concerning the time complexity of the construction of such layouts for both the two congestion
measures, that is we exactly determine all the tractable and intractable cases. Then, we provide some combinatorial bounds
for arbitrary networks, together with optimal layouts for specific topologies such as chains, rings and grids.
Received: December 1997 / Accepted: August 2000 相似文献