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排序方式: 共有1631条查询结果,搜索用时 15 毫秒
151.
Giulio Giovannetti Francesca Frijia Simona Attanasio Luca Menichetti Valentina Hartwig Nicola Vanello Jan Henrik Ardenkjaer-Larsen Daniele De Marchi Vincenzo Positano Rolf Schulte Luigi Landini Massimo Lombardi Maria Filomena Santarelli 《Measurement》2013
Hyperpolarized 13C magnetic resonance spectroscopy in pig models enables cardiac metabolism assessment and provides a powerful tool for heart physiology studies, although the low molar concentration of derivate metabolites gives rise to technological limitations in terms of data quality. The design of dedicated coils capable of providing large field of view with high Signal-to-Noise Ratio (SNR) data is of fundamental importance. 相似文献
152.
153.
Massimo Stefani Stefania Rigacci 《International journal of molecular sciences》2013,14(6):12411-12457
Amyloid aggregation is a hallmark of several degenerative diseases affecting the brain or peripheral tissues, whose intermediates (oligomers, protofibrils) and final mature fibrils display different toxicity. Consequently, compounds counteracting amyloid aggregation have been investigated for their ability (i) to stabilize toxic amyloid precursors; (ii) to prevent the growth of toxic oligomers or speed that of fibrils; (iii) to inhibit fibril growth and deposition; (iv) to disassemble preformed fibrils; and (v) to favor amyloid clearance. Natural phenols, a wide panel of plant molecules, are one of the most actively investigated categories of potential amyloid inhibitors. They are considered responsible for the beneficial effects of several traditional diets being present in green tea, extra virgin olive oil, red wine, spices, berries and aromatic herbs. Accordingly, it has been proposed that some natural phenols could be exploited to prevent and to treat amyloid diseases, and recent studies have provided significant information on their ability to inhibit peptide/protein aggregation in various ways and to stimulate cell defenses, leading to identify shared or specific mechanisms. In the first part of this review, we will overview the significance and mechanisms of amyloid aggregation and aggregate toxicity; then, we will summarize the recent achievements on protection against amyloid diseases by many natural phenols. 相似文献
154.
The scope for diffusion of very low-enthalpy geothermal plants in the Piemonte region of Italy, using groundwater heat pumps (GWHP), was analyzed to check environmental sustainability and the benefits in terms of reducing greenhouse gas emissions from fossil fuels. GWHP implementation seemed particularly suitable to the specific characteristics of the Piemonte plain. An important thick and productive shallow aquifer is present across the entire plain beneath the major energy users and is therefore appropriate for geothermal energy development purposes. The building stock could be adapted to heat pumps in different ways, but objective-oriented policies will be required to reach the best results in terms of environmental benefits. 相似文献
155.
Cristiano Nicolella Antonio Bertei Massimo Viviani Antonio Barbucci 《Journal of Applied Electrochemistry》2009,39(4):503-511
This paper presents a mathematical model of mass and charge transport and electrochemical reaction in porous composite cathodes
for application in solid oxide fuel cells. The model describes a porous composite cathode as a continuum, and characterises
charge and mass transfer and electrochemical kinetics using effective parameters (i.e. conductivity, diffusivity, exchange
current) related to morphology and material properties by percolation theory. The model accounts for the distribution of morphological
properties (i.e. porosity, tortuosity, density of contacts among particles) along cathode thickness, as experimentally observed
on scanning electron microscope images of LSM/YSZ cathodes of varying thickness. This feature allows the model to reproduce
the dependence of polarisation resistance on thickness, as determined by impedance spectroscopy on LSM/YSZ cathodes of varying
thickness. Polarisation resistance in these cathodes is almost constant for thin cathodes (up to 10 μm thickness), it sharply
decreases for intermediate thickness, to reach a minimum value for about 50 μm thickness, then it slightly increases in thicker
cathodes. 相似文献
156.
Davinson Mariano da Silva Luciana Reyes Pires Kassab Massimo Olivero Thiago B.N. Lemos Douglas V. da Silva A.S.L. Gomes 《Optical Materials》2011,33(12):1902-1906
The authors report the fabrication and characterization of active waveguides in GeO2–PbO–Ga2O3 glass samples doped with Er3+, written with a femtosecond laser delivering pulses of 150 fs duration at 1 kHz repetition rate. Permanent refractive index change was obtained and waveguides were formed under different laser pulse energies and scan velocities. The passive and active optical properties of the waveguides were investigated. The minimum value of propagation loss was of 4.8 dB/cm. Optical amplification at 1.5 μm under 980 nm excitation was observed showing a maximal internal gain of 2.7 dB/cm. 相似文献
157.
We compare and contrast teacher-centered and student-centered paradigms of engineering education. We identify the following seven roles for teachers wishing to adopt a student-centered paradigm: 1) model thinking/processing skills, 2) identify students' cognitive development, 3) develop questions that facilitate exploration/growth, 4) introduce visual tools to aid establishing connections, 5) provide group learning settings, 6) use analogies and metaphors, and 7) provide a “no-risk” student feedback channel for information. Several case studies for different subjects and from different institutions are presented. Our results indicate a student-centered model is most effective when coupled with academic depth and experience in the subject matter. 相似文献
158.
Hawkins J. David; Catalano Richard F.; Wells Elizabeth A. 《Canadian Metallurgical Quarterly》1986,54(5):661
Examined the effectiveness of a supplemental skills training and social-network-development aftercare program with 130 drug abusers (aged 15–55 yrs) from 4 residential therapeutic communities. The program included training in assertiveness, problem-solving, stress management, and giving and receiving praise; training techniques included group discussion, modeling, role playing and feedback. Pre- and posttesting with a problem situation inventory showed that the intervention produced positive effects on Ss' performance at the conclusion of treatment. Performance improved in situations involving avoidance of drug use, coping with drug relapse, social interaction, interpersonal problem solving, and coping with stress. It is concluded that as a reentry strategy, the supplemental intervention is an effective adjunct to residential treatment. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
159.
Daniela Aiello Flaviano Testa Rosario Aiello Luca Malfatti Tongjit Kidchob Plinio Innocenzi Iolinda Aiello Tonino Martino Mauro Ghedini Massimo La Deda 《Inorganic chemistry communications》2009,12(3):237-239
A luminescent zinc complex was successfully incorporated to mesostructured porous titania films through a grafting process. The resulting films show an intense blue-emission increasing with functionalization time. The emission quantum yield of these newly synthesized films was quantitatively and accurately determined by measurements carried by an integrating sphere. 相似文献
160.
Massimo Marezio Edgar T. Alexandre Pierre Bordet Jean-Jacques Capponi Catherine Chaillout Evgueni M. Kopnin Sergio M. Loureiro Paolo G. Radaelli Gustaaf Van Tendeloo 《Journal of Superconductivity》1995,8(4):507-510
Cu and C substitution for Hg in Hg-based cuprate superconductors is discussed. The large Hg Debye-Waller factor usually obtained from refinements based on diffraction data should be interpreted as an indication of carbon substitution for the Hg cations. This assumption is corroborated by HREM, powder x-ray anomalous dispersion, and powder neutron diffraction investigations. 相似文献