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51.
52.
Adipocytic tumors are the most common subtype of soft tissue tumors. In current clinical practice, distinguishing benign lipomas from well-differentiated liposarcomas (WDLPS), as well as dedifferentiated liposarcomas (DDLPS) from their morphologic mimics, remains a significant diagnostic challenge. This is especially so when examining small biopsy samples and without the aid of additional ancillary tests. Recognizing the important role that microRNAs (miRNAs) play in tumorigenesis and their potential utility in tumor classification, we analyzed routine clinical tissue samples of benign and malignant lipomatous tumors, as well as other sarcoma mimics, to identify distinguishing miRNA-based signatures that can aid in the differential diagnosis of these entities. We discovered a 6-miRNA signature that separated lipomas from WDLPS with high confidence (AUC of 0.963), as well as a separate 6-miRNA signature that distinguished DDLPS from their more aggressive histologic mimics (AUC of 0.740). Functional enrichment analysis unveiled possible mechanistic involvement of these predictive miRNAs in adipocytic cancer-related biological processes and pathways such as PI3K/AKT/mTOR and MAPK signaling, further supporting the relevance of these miRNAs as biomarkers for adipocytic tumors. Our results demonstrate that miRNA expression profiling may potentially be used as an adjunctive tool for the diagnosis of benign and malignant adipocytic tumors. Further validation studies are warranted.  相似文献   
53.
The pH variations of Mg, Zn and Al solutions to which had been added the rare earth metals Nd, Pr and Y were observed in 3.5 wt.% NaCl with respect to high energy mechanical ball milling effects. Mg was directly dissolved and exhibited a pH value of 10.5. On the other hand, Zn and Al needed to be saturated for a certain amount of time. The addition of rare earth metals played a role in increasing the pH with low reduction potentials. Additionally, mechanical ball milling provided high energy to Mg + x wt.% Zn + 0.5 wt.% Nd mixture by fracturing fragmentation of metals, which led to an increase in the pH when the mixture was immersed in 3.5 wt.% NaCl. The addition of Zn to Mg + 0.5 wt.% Nd caused a higher pH than when Mg + 0.5 wt.% Nd alone was added.  相似文献   
54.
Eight current-mode first-order allpass networks using second-generation current conveyors (CCII) are presented. Each of the proposed circuits employs two CCIIs, two grounded capacitors and two grounded resistors. The networks offer high output impedances. Experimental results are also included.  相似文献   
55.
We study the issue of quality of service (QoS) for real-time traffic over a wireless channel deploying automatic repeat request (ARQ) error control. An analytical model has been derived to evaluate the queueing related loss and the wireless channel related loss. In contrast to previous work, this model quantifies the interaction between the network layer and the physical layer, and then it enables the admission controllers of wireless networks to improve utilization while satisfying the traffic QoS constraints through cross-layer design techniques.  相似文献   
56.
Transient phenomena of hybrid Raman/erbium-doped fiber amplifier (EDFA) upon optical channel add-drop are investigated. The transient responses of surviving channels are resulted from the combined dynamics of Raman amplifier and EDFA. It is shown that the suggested method employing fast gain control of EDFA only can effectively suppress the transient variation of output power. The transient-suppressing hybrid Raman/EDFA is proven to be enough for wavelength-division-multiplexing networks including reconfigurable optical add-drop multiplexer and/or transparent optical cross-connect, if the optical switching speed is carefully chosen.  相似文献   
57.
Constrained by the physical environments, the long‐thin topology has recently been promoted for many practical deployments of wireless sensor networks (WSNs). In general, a long‐thin topology is composed of a number of long branches of sensor nodes, where along a branch each sensor node has only one potential parent node toward the sink node. Although data aggregation may alleviate excessive packet contention, the maximum payload size of a packet and the dynamically changing traffic loads may severely affect the amount of sensor readings that may be collected along a long branch of sensor nodes. In addition, many practical applications of long‐thin WSNs demand the exact sensor readings at each location along the deployment areas for monitoring and analysis purposes, so sensor readings may not be aggregated when they are collected. This paper proposes a lightweight, self‐adaptive scheme that designates multiple collection nodes, termed lock gates, along a long‐thin network to collect sensor readings sent from their respective upstream sensor nodes. The self‐adaptive lock gate designation scheme balances between the responsiveness and the congestion of data collection while mitigating the funneling effect. The scheme also dynamically adapts the designation of lock gates to accommodate the time‐varying sensor reading generation rates of different sensor nodes. A testbed of 100 Jennic sensor nodes is developed to demonstrate the effectiveness of the proposed lock gate designation scheme. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
58.
This paper presents near-field (NF) and far-field (FF) analysis of alternating impedance electromagnetic bandgap (AI-EBG) structure in packages and boards. Three test vehicles have been designed and fabricated for NF and FF measurements. Simulation results using a full-wave solver (SONNET) have been compared with measurement results. This paper investigates the radiation due to return current on different reference planes. The analysis results from simulations and measurements provide important guidelines for design of the AI-EBG structure based power distribution network for noise isolation and suppression in mixed-signal systems  相似文献   
59.
In this work, an aqueous acidic thin‐layer‐based strategy for fabricating nanostructures on silicon by using atomic force microscopy (AFM) nanolithography is presented. The approach involves the formation of microscale droplets via dilute hydrofluoride (DHF) etching, the conversion of the droplets to acidic thin layers by AFM‐probe scanning, and subsequent lithographic operations using a biased probe in the aqueous layers. By varying the concentration of the acidic DHF layers, the thin layers can facilitate the creation of both positive and negative patterns, such as oxide dots and Si pores, through anodic oxidation and dissolution. In particular, the anodic oxidation in the acidic media is associated with the field‐enhanced nonequilibrium dissociation of the weak electrolyte. The Si pore structure formation is related to the field‐assisted dissolution of anodic oxides and the Si substrate. The acidic‐layer‐based technique allows switching between different lithographic modes by changing the acidity of the DHF layers, and is complementary to bulk solution‐based and local meniscus‐based approaches in AFM nanolithography. In principle, this method can also be extended to other materials that have similar reactions with DHF.  相似文献   
60.
Dynamic spectrum management for next-generation DSL systems   总被引:1,自引:0,他引:1  
The performance of DSL systems is severely constrained by crosstalk due to the electromagnetic coupling among the multiple twisted pairs making up a phone cable. In order to reduce performance loss arising from crosstalk, DSL systems are currently designed under the assumption of worst-case crosstalk scenarios leading to overly conservative DSL deployments. This article presents a new paradigm for DSL system design, which takes into account the multi-user aspects of the DSL transmission environment. Dynamic spectrum management (DSM) departs from the current design philosophy by enabling transceivers to autonomously and dynamically optimize their communication settings with respect to both the channel and the transmissions of neighboring systems. Along with this distributed optimization, when an additional degree of coordination becomes available for future DSL deployment, DSM will allow even greater improvement in DSL performance. Implementations are readily applicable without causing any performance degradation to the existing DSLs under static spectrum management. After providing an overview of the DSM concept, this article reviews two practical DSM methods: iterative water-filling, an autonomous distributed power control method enabling great improvement in performance, which can be implemented through software options in some existing ADSL and VDSL systems; and vectored-DMT, a coordinated transmission/reception technique achieving crosstalk-free communication for DSL systems, which brings within reach the dream of providing universal Internet access at speeds close to 100 Mb/s to 500 m on 1-2 lines and beyond 1 km on 2-4 lines. DSM-capable DSL thus enables the broadband age.  相似文献   
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