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排序方式: 共有3061条查询结果,搜索用时 31 毫秒
31.
Davide Barbagallo Angela Caponnetto Cristina Barbagallo Rosalia Battaglia Federica Mirabella Duilia Brex Michele Stella Giuseppe Broggi Roberto Altieri Francesco Certo Rosario Caltabiano Giuseppe Maria Vincenzo Barbagallo Carmelina Daniela Anfuso Gabriella Lupo Marco Ragusa Cinzia Di Pietro Thomas Birkballe Hansen Michele Purrello 《International journal of molecular sciences》2021,22(4)
Circular RNAs (circRNAs) are a large class of RNAs with regulatory functions within cells. We recently showed that circSMARCA5 is a tumor suppressor in glioblastoma multiforme (GBM) and acts as a decoy for Serine and Arginine Rich Splicing Factor 1 (SRSF1) through six predicted binding sites (BSs). Here we characterized RNA motifs functionally involved in the interaction between circSMARCA5 and SRSF1. Three different circSMARCA5 molecules (Mut1, Mut2, Mut3), each mutated in two predicted SRSF1 BSs at once, were obtained through PCR-based replacement of wild-type (WT) BS sequences and cloned in three independent pcDNA3 vectors. Mut1 significantly decreased its capability to interact with SRSF1 as compared to WT, based on the RNA immunoprecipitation assay. In silico analysis through the “Find Individual Motif Occurrences” (FIMO) algorithm showed GAUGAA as an experimentally validated SRSF1 binding motif significantly overrepresented within both predicted SRSF1 BSs mutated in Mut1 (q-value = 0.0011). U87MG and CAS-1, transfected with Mut1, significantly increased their migration with respect to controls transfected with WT, as revealed by the cell exclusion zone assay. Immortalized human brain microvascular endothelial cells (IM-HBMEC) exposed to conditioned medium (CM) harvested from U87MG and CAS-1 transfected with Mut1 significantly sprouted more than those treated with CM harvested from U87MG and CAS-1 transfected with WT, as shown by the tube formation assay. qRT-PCR showed that the intracellular pro- to anti-angiogenic Vascular Endothelial Growth Factor A (VEGFA) mRNA isoform ratio and the amount of total VEGFA mRNA secreted in CM significantly increased in Mut1-transfected CAS-1 as compared to controls transfected with WT. Our data suggest that GAUGAA is the RNA motif responsible for the interaction between circSMARCA5 and SRSF1 as well as for the circSMARCA5-mediated control of GBM cell migration and angiogenic potential. 相似文献
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Valeria Ciaffaglione Prof. Maria N. Modica Prof. Valeria Pittalà Prof. Giuseppe Romeo Prof. Loredana Salerno Dr. Sebastiano Intagliata 《ChemMedChem》2021,16(23):3496-3512
The development of potent antitumor agents with a low toxicological profile against healthy cells is still one of the greatest challenges facing medicinal chemistry. In this context, the “mutual prodrug” approach has emerged as a potential tool to overcome undesirable physicochemical features and mitigate the side effects of approved drugs. Among broad-spectrum chemotherapeutics available for clinical use today, 5-fluorouracil (5-FU) is one of the most representative, also included in the World Health Organization model list of essential medicines. Unfortunately, severe side effects and drug resistance phenomena are still the primary limits and drawbacks in its clinical use. This review describes the progress made over the last ten years in developing 5-FU-based mutual prodrugs to improve the therapeutic profile and achieve targeted delivery to cancer tissues. 相似文献
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Inter-domain routing data and Internet active probing measurements are two types of information commonly available in huge datasets and subject to extensive, focused analysis. However, the study of the correlation between these two complementary types of information still remains one of the most challenging problems in today’s research in networking. In this paper we describe a metaphor for the visualization of the interplay between the routing information exchanged via BGP and the round-trip delay measurements collected by several geolocated probes. We implemented a prototype based on the above metaphor. Our prototype highlights both the Autonomous System topology and the latency associated with each AS-path over time. Further, it shows how probes are partitioned into clusters associated with each border gateway, based on observed traffic patterns. The resulting visualization allows the user to explore the dynamics of the correlation between the two types of information. 相似文献
36.
Hans-Joachim Kleebe Giuseppe Pezzotti 《Journal of the American Ceramic Society》2002,85(12):3049-3053
The grain-boundary structure of a model SiAlON polycrystal with nominal composition Si5 AlON7 was characterized by transmission electron microscopy (TEM) both in an equilibrium (as-processed) state at room temperature and after quenching from elevated temperature. In addition, low-frequency (1–13 Hz) internal friction data were recorded as a function of temperature, showing a pronounced grain-boundary sliding peak positioned at 1030°C. High-resolution transmission electron microscopy (HRTEM) of the equilibrated low-temperature microstructure revealed residual glass only at multigrain junctions, but no amorphous intergranular films were observed. The detection of clean interfaces in the as-processed sample contradicts the internal friction data, which instead suggests the presence of a low-viscosity grain boundary phase, sliding at elevated temperatures. Therefore, a thin section of the as-sintered material was heated to 1380°C and rapidly quenched. HRTEM analysis of this sample showed, apart from residual glass pockets, wetted grain boundaries, which is in line with the internal friction experiment. This wetting-dewetting phenomenon observed in z = 1 SiAlON is expected to have a strong impact not only on high-temperature engineering ceramics but also on geological, temperature-activated processes such as volcanic eruptions. 相似文献
37.
Occurrence patterns of alien freshwater turtles in a large urban pond ‘Archipelago’ (Rome,Italy): Suggesting hypotheses on root causes 下载免费PDF全文
Maria Paola Di Santo Leonardo Vignoli Giuseppe M. Carpaneto Corrado Battisti 《Lakes & Reservoirs: Research and Management》2017,22(1):56-64
The patterns of the occurrence and distribution of alien freshwater turtle species in an urban pond archipelago (Rome, Italy) were analysed, with the aim of exploring the role of a set of factors (type of ponds, landscape context, size area, distance from the nearest road) with a generalized linear model approach. A total of 311 ponds subdivided in three types (fountains, small basins, lakes) embedded in different landscape contexts (public parks, private parks, urban areas) at differing distances from the nearest road were sampled. Six non‐native freshwater turtle species in 31 sites were recorded (9.97%). Lakes exhibited the highest occurrence rates of alien freshwater turtles, compared to small basins and fountains. Freshwater turtle species in urbanized areas were only observed in parks (both public and private). In both the public and private parks, the lakes exhibited the highest percentage of occupied sites, with fountains being the lowest. A direct and significant relationship was observed between pond size and species richness. The distance from the nearest road did not appear to affect species richness. A first interpretation of the data from this study facilitated the postulation of two a posteriori hypotheses that should be tested, as follows: (i) the causal process of turtle release is random, and the rate of extinction (and recapture) is higher in smaller ponds, thus producing the observed pattern; and (ii) the turtle release is not random, and people actively select the ponds they consider more suitable for their pet animals. In this study, it appears the lakes were perceived by those who abandon their pets as the most ecologically suitable habitats among other pond types to accommodate the different species of turtles. Knowledge of people's attitudes in regard to releasing pet animals also might assist managers of public green spaces to develop strategies aimed to preserve local biodiversity, and to educate the public about the conservation issue represented by the alien species. 相似文献
38.
A 2-layer drawing represents a bipartite graph where each vertex is a point on one of two parallel lines, no two vertices on the same line are adjacent, and the edges are straight-line segments. In this paper we study 2-layer drawings where any two crossing edges meet at right angle. We characterize the graphs that admit this type of drawing, provide linear-time testing and embedding algorithms, and present a polynomial-time crossing minimization technique. Also, for a given graph G and a constant k, we prove that it is $\mathcal{NP}$ -complete to decide whether G contains a subgraph of at least k edges having a 2-layer drawing with right angle crossings. 相似文献
39.
Giuseppe Placidi Danilo Avola Marco Ferrari Daniela Iacoviello Andrea Petracca Valentina Quaresima Matteo Spezialetti 《Computer methods and programs in biomedicine》2014
Background and objective
The degeneration of the balance control system in the elderly and in many pathologies requires measuring the equilibrium conditions very often. In clinical practice, equilibrium control is commonly evaluated by using a force platform (stabilometric platform) in a clinical environment.In this paper, we demonstrate how a simple movement analysis system, based on a 3D video camera and a 3D real time model reconstruction of the human body, can be used to collect information usually recorded by a physical stabilometric platform.Methods
The algorithm used to reconstruct the human body model as a set of spheres is described and discussed. Moreover, experimental measurements and comparisons with data collected by a physical stabilometric platform are also reported. The measurements were collected on a set of 6 healthy subjects to whom a change in equilibrium condition was stimulated by performing an equilibrium task.Results
The experimental results showed that more than 95% of data collected by the proposed method were not significantly different from those collected by the classic platform, thus confirming the usefulness of the proposed system.Conclusions
The proposed virtual balance assessment system can be implemented at low cost (about 500$) and, for this reason, can be considered a home use medical device. On the contrary, astabilometric platform has a cost of about 10,000$ and requires periodical calibration. The proposed system does not require periodical calibration, as is necessary for stabilometric force platforms, and it is easy to use. In future, the proposed system with little integration can be used, besides being an emulator of a stabilometric platform, also to recognize and track, in real time, head, legs, arms and trunk, that is to collect information actually obtained by sophisticated optoelectronic systems. 相似文献40.
Giuseppe Ajroldi Maurizio Pianca Massimiliano Fumagalli Giovanni Moggi 《Polymer》1989,30(12):2180-2187
The dynamic-mechanical properties of some fluoroelastomers were determined as a function of composition at low frequency (≈ 1 Hz), by means of a free oscillation torsion pendulum, between −180°C and the softening point. Vinylidenefluoride (VDF)-hexafluoropropene (HFP) copolymers of molar composition 0–39% HFP and terpolymers of VDF and HFP with up to 30mol% tetrafluoroethylene (TFE) and a constant VDF to HFP molar ratio of 3.4 were considered. Two relaxation processes typical of the amorphous phase were found. The first, located at about −87°C, is related to local motions and the transition temperature was found to be independent of composition for copolymers, while it depends on TFE molar content for terpolymers. The second is related to the glass transition and the transition temperature depends on the composition. However, for semicrystalline copolymers the double glass transition phenomenon was observed. When crystallinity goes to zero at about 20 mol% HFP, only one transition is observed. It was also found that ordered structures can take place for terpolymers when TFE molar concentration exceeds 20%. The crystal disorder transition of pure PVDF (75°C) is observed also for low HFP concentrations but the transition temperature is strongly reduced. Analogies between the VDF-HFP and E-P systems are also discussed. 相似文献