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排序方式: 共有1001条查询结果,搜索用时 359 毫秒
91.
Lido Calorini Anna Fallani Donatella Tombaccini Emanuela Barletta Gabriele Mugnai Maria F. Di Renzo Paolo M. Comoglio Salvatore Ruggieri 《Lipids》1989,24(8):685-690
To determine whether a metastatic phenotype may be corelated with a characteristic lipid pattern, we compared the lipid composition
of low metastasizing Balb/c 3T3 cells transformed by the B77 strain of Rous sarcoma virus (B77-3T3 cells) with that of a subclone
isolated by growth in 0.6% agar, the B77-AA6 cells, which exhibit a high capacity for spontaneous metastasis. B77-3T3 cells
revealed characteristics in their lipid composition common to other systems of transformed cells, i.e., an accumulation of
ether-linked lipids, a reduction of the more complex gangliosides, an increase of oleic acid (18∶1) and a decrease of arachidonic
(20∶4) and C22 polyunsaturated fatty acids in phospholipids. High metastatic B77-AA6 cells showed: a) an even more marked
decrease of complex gangliosides; b) a more pronounced increase of 18∶1 and decrease of 20∶4 and 22 polyunsaturated fatty
acids in certain phospholipid classes; and c) a higher percentage of alkyl-acyl subfractions in both phosphatidylcholine and
phosphatidylethanolamine than B77-3T3 cells.
Comparing the data for other systems of metastatic cells with those of lipid studies of spontaneously metastasizing B77-AA6
cell system leads us to conclude that the metastatic phenotype is characterized by a change in ether-linked lipids, rather
than in fatty acids. 相似文献
92.
93.
Antonio Angrisano Salvatore Gaglione Salvatore Troisi 《Wireless Personal Communications》2014,79(1):211-221
In global navigation satellite systems (GNSS) navigation the receiver and satellite clocks play a key role. The receivers are usually equipped with inaccurate quartz clocks, which experiment large drift relative to system time and consequently offset growing very fast; receiver manufactures bound the magnitude of the receiver clock offset to prevent it becomes too large and the actual bounding procedures vary from one manufacturer to another. The most common approach consists of introducing discrete jumps when the offset exceeds a threshold (usually 1 ms). This method is common in low-cost GNSS receivers and influences several applications as differential positioning, cycle-slip detection, precise point positioning technique, absolute positioning with Kalman filter. In this work some techniques to detect and account for millisecond clock jump, suitable for code positioning of a single receiver with Kalman filter, are proposed. Two deterministic algorithms to detect receiver clock jumps are shown: in measurement and parameter domain. The technique in measurement domain uses current pseudorange measurements compared with pseudorange and Doppler measurements at previous epoch; the technique in parameter domain compares current and previous least squares estimations of receiver clock bias, considering the clock drift. Two different approaches are described to account for the clock jumps, once detected, a deterministic one, consisting of fixing the pseudorange discontinuities, and a statistic one, consisting of suitably varying the Kalman filter settings. A static GNSS data set is processed with and without the proposed algorithms to demonstrate their efficiency. 相似文献
94.
Transient Electronics: Wireless Microfluidic Systems for Programmed,Functional Transformation of Transient Electronic Devices (Adv. Funct. Mater. 32/2015)
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95.
96.
Di Bartolomeo A Giubileo F Santandrea S Romeo F Citro R Schroeder T Lupina G 《Nanotechnology》2011,22(27):275702
We discuss the origin of an additional dip other than the charge neutrality point observed in the transfer characteristics of graphene-based field-effect transistors with a Si/SiO2 substrate used as the back-gate. The double dip is proved to arise from charge transfer between the graphene and the metal electrodes, while charge storage at the graphene/SiO2 interface can make it more evident. Considering a different Fermi energy from the neutrality point along the channel and partial charge pinning at the contacts, we propose a model which explains all the features observed in the gate voltage loops. We finally show that the double dip enhanced hysteresis in the transfer characteristics can be exploited to realize graphene-based memory devices. 相似文献
97.
Salvatore AielloGiuseppe Campione Giovanni MinafòNunzio Scibilia 《Engineering Structures》2011,33(12):3402-3408
Several experimental investigations in the past few years have highlighted the fact that the compressive strength of glass was significantly higher than its tensile strength, allowing new applications of glass in compression members. However, due to the high slenderness of structural glass elements made of thin glass panels, they tend to fail in a brittle manner. A substantial amount of fundamental research has been carried out in the past few years to investigate the stability behaviour of structural glass elements. However, although buckling of glass panels has been quite well studied, a very poor amount of research has been addressed to glass columns, which by contrast represent the most interesting case due to their direct application in buildings. In this paper, the results of ten compressive tests on glass panels and columns are presented and discussed. The main variables considered were slenderness of panels and the shape of the cross-section for columns. The results of six bending tests on monolithic and laminated glass panels are also shown, and the level of connection between the glass sheets was evaluated. A review of the theoretical background is provided and the results achievable with existing analytical models are compared. 相似文献
98.
Jordi Perelló Annalisa Morea Salvatore Spadaro Albert Pagès Sergio Ricciardi Matthias Gunkel Gabriel Junyent 《Photonic Network Communications》2014,28(3):276-286
Network survivability requires the provisioning of backup resources in order to protect active traffic against any failure scenario. Backup resources, however, can remain unused most of the time while the network is not in failure condition, inducing high power consumption wastage, if fully powered on. In this paper, we highlight the power consumption wastage of the additional resources for survivability in IP/multi-protocol label switching (MPLS) over dense wavelength division multiplexing multi-layer optical networks. We assume MPLS protection switching as the failure recovery mechanism in the network, a solution interesting for current network operators to ensure fast recovery as well as fine-grained recovery treatment per label switched path. Next, we quantitatively show how elastic optical technologies can effectively reduce such a power consumption by dynamically adjusting the data rate of the transponders to the carried amount of traffic. 相似文献
99.
What is available to psychologists to assist them in identifying or minimizing the damage that can result from inappropriate professional boundary crossings? Frequency data of both sexual and nonsexual boundary violations by psychologists are provided as they occurred with clients, supervisees, and students. The impact of engaging in such relationships on subsequent professional practice is also reported. Data on 18 nonsexual boundary crossings are described, and guidelines for making decisions about crossing accepted professional boundaries are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Effects of the degree of undercooling on flow induced crystallization in polymer melts 总被引:1,自引:0,他引:1
This study investigates the coupled effects of mild shear flow and temperature on the crystallization behavior of two thermoplastic polymers, namely, an isotactic polypropylene and an isotactic poly(1-butene). Rheological experiments are used to measure the crystallization induction time under isothermal, steady shear flow conditions. The experimental results clearly show the effects of the degree of undercooling on flow-induced crystallization (FIC). As temperature decreases, the corresponding increase in chain orientation at a given shear rate leads to an absolutely faster crystallization. At the same time, however, a temperature decrease makes the flow-induced driving force to crystallization relatively less influent with respect to the intrinsic kinetics. A FIC model based on the Doi-Edwards micro-rheological theory is shown to successfully describe the quantitative details of the observed experimental behavior. 相似文献