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排序方式: 共有3475条查询结果,搜索用时 15 毫秒
31.
32.
Calogero D. Presti Francesco Carrara Giuseppe Palmisano 《Analog Integrated Circuits and Signal Processing》2007,51(1):51-54
A variable-gain up-conversion mixer for 5-GHz WLAN applications is presented, whose input stage is based on a novel variable
gain transconductor. The proposed topology features reduced power consumption by exploiting dc current reuse for mixer biasing.
Moreover, a new low-consumption control circuit is introduced, which achieves a temperature-stable and linear-in-dB characteristic,
providing a 40-dB dynamic range within ±1 dB gain error. 相似文献
33.
Marco Lucamarini Alessandro Ceré Giovanni Di Giuseppe Stefano Mancini David Vitali Paolo Tombesi 《Open Systems & Information Dynamics》2007,14(2):169-178
The security of a deterministic quantum scheme for communication, namely the LM05 [1], is studied in presence of a lossy channel
under the assumption of imperfect generation and detection of single photons. It is shown that the scheme allows for a rate
of distillable secure bits higher than that pertaining to BB84 [2]. We report on a first implementation of LM05 with weak
pulses. 相似文献
34.
35.
When immersed in a disturbing electromagnetic field, electronic systems are subject to interference due to the energy injected by the external field into the system through the electronic units and, especially, through the transmission lines connecting units one another. The issue of reducing the unwanted energy injection through connecting transmission lines is addressed in this contribution from the point of view of the routing, i.e. of the disposition of the connecting lines that minimizes the injection. The problem is formulated as an optimization problem, dealt with by the simulated annealing minimization technique combined with an efficient way of computing the field coupling to the lines. Results are reported for various cases, and the relation between the characteristics of the interfering field and the efficiency of the reduction is discussed. 相似文献
36.
AI Robles ML Rodriguez-Puebla AB Glick C Trempus L Hansen P Sicinski RW Tennant RA Weinberg SH Yuspa CJ Conti 《Canadian Metallurgical Quarterly》1998,12(16):2469-2474
Cyclin D1 is part of a cell cycle control node consistently deregulated in most human cancers. However, studies with cyclin D1-null mice indicate that it is dispensable for normal mouse development as well as cell growth in culture. Here, we provide evidence that ras-mediated tumorigenesis depends on signaling pathways that act preferentially through cyclin D1. Cyclin D1 expression and the activity of its associated kinase are up-regulated in keratinocytes in response to oncogenic ras. Furthermore, cyclin D1 deficiency results in up to an 80% decrease in the development of squamous tumors generated through either grafting of retroviral ras-transduced keratinocytes, phorbol ester treatment of ras transgenic mice, or two-stage carcinogenesis. 相似文献
37.
High-computing speed and modularity have made RNS-based arithmetic processors attractive for a long time, especially in signal processing, where additions and multiplications are very frequent. The VLSI technology renewed this interest because RNS-based circuits are becoming more feasible; however, intermodular operations degradate their performance and a great effort results on this topic. In this paper, we deal with the problem of performing the basic operationX(modm), that is the remainder of the integer divisionX/m, for large values of the integerX, following an approximating and correcting approach, which guarantees the correctness of the result. We also define a structure to computeX(modm) by means of few fast VLSI binary multipliers, which is exemplified for 32-bit long numbers, obtaining a total response time lower than 200 nsec. Furthermore, such a structure is evaluated in terms of VLSI complexity and area and time figuresA=?(n 2 T m 2 ) andT=?(T M ) for the parameterT M in \([\log n,\sqrt n ]\) are derived. A simple positional-to-residue converter is finally presented, based on this structure; it improves some complexity results previously obtained by authors. 相似文献
38.
Monica Bianco Ilenia Viola Miriam Cezza Francesca Pietracaprina Giuseppe Gigli Rosaria Rinaldi Valentina Arima 《Microfluidics and nanofluidics》2012,13(3):399-409
Solid surface/liquid interactions play an important role in microfluidics and particularly in manipulation of films, drops and bubbles, a basic requirement for a number of lab-on-chip applications. The behavior of solvents in coated microchannels is difficult to be predicted considering theories; therefore, experimental methods able to estimate the properties at the interface in real time and during the operational regime are amenable. Here, we propose to use an experimental setup to evaluate the effective dynamics of solvents inside PDMS microchannels. The influence of the solvent properties as well as of the channel wall’s wettability on the fluid movements was evaluated. Modification of the channel properties was achieved by introducing Teflon coatings that allow producing stable hydrophobic microchannel walls. The results were fitted according to Washburn-type power-law and compared with theoretical calculations of the parameter β that expresses the dependence of capillary dynamics on surface tension γ, liquid viscosity η, contact angles θ and the hydraulic radius R H. A comparison between the calculated and the experimental values reveled that parameters other than the contemplated ones influenced the measurements. The main parameter that affects the flow of solvents such as water, methanol ethanol, dimethylformamide, acetonitrile and acetone was found to be the γ/η ratio. Considering these results, the investigation tool described here is believed to be promising to predict the dynamics of common organic solvents inside integrated functional fluidic devices and to accurately control solvent flow, particularly in capillary-driven pumpless systems, a basic requirement for widening the application range of PDMS lab-on-chip devices. 相似文献
39.
Roberto Lande Immacolata Pietraforte Anna Mennella Raffaella Palazzo Francesca Romana Spinelli Konstantinos Giannakakis Francesca Spadaro Mario Falchi Valeria Riccieri Katia Stefanantoni Curdin Conrad Cristiano Alessandri Fabrizio Conti Loredana Frasca 《International journal of molecular sciences》2021,22(4)
LL37 acts as T-cell/B-cell autoantigen in Systemic lupus erythematosus (SLE) and psoriatic disease. Moreover, when bound to “self” nucleic acids, LL37 acts as “danger signal,” leading to type I interferon (IFN-I)/pro-inflammatory factors production. T-cell epitopes derived from citrullinated-LL37 act as better antigens than unmodified LL37 epitopes in SLE, at least in selected HLA-backgrounds, included the SLE-associated HLA-DRB1*1501/HLA-DRB5*0101 backgrounds. Remarkably, while “fully-citrullinated” LL37 acts as better T-cell-stimulator, it loses DNA-binding ability and the associated “adjuvant-like” properties. Since LL37 undergoes a further irreversible post-translational modification, carbamylation and antibodies to carbamylated self-proteins other than LL37 are present in SLE, here we addressed the involvement of carbamylated-LL37 in autoimmunity and inflammation in SLE. We detected carbamylated-LL37 in SLE-affected tissues. Most importantly, carbamylated-LL37-specific antibodies and CD4 T-cells circulate in SLE and both correlate with disease activity. In contrast to “fully citrullinated-LL37,” “fully carbamylated-LL37” maintains both innate and adaptive immune-cells’ stimulatory abilities: in complex with DNA, carbamylated-LL37 stimulates plasmacytoid dendritic cell IFN-α production and B-cell maturation into plasma cells. Thus, we report a further example of how different post-translational modifications of a self-antigen exert complementary effects that sustain autoimmunity and inflammation, respectively. These data also show that T/B-cell responses to carbamylated-LL37 represent novel SLE disease biomarkers. 相似文献
40.
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