8,251 research outputs found
Valley-symmetry-preserved transport in ballistic graphene with gate-defined carrier guiding
No full textEver since the discovery of graphene(1), valley symmetry and its control(2,3) in the material have been a focus of continued studies in relation to valleytronics(4,5). Carrier-guiding quasi-one-dimensional (1D) graphene nanoribbons (GNRs)(6-12) with quantized energy subbands preserving the intrinsic Dirac nature have provided an ideal system to that end. Here, by guiding carriers through dual-gate operation in high-mobility monolayer graphene, we report the realization of quantized conductance in steps of 4e(2)/h in zero magnetic field, which arises from the full symmetry conservation of quasi-1D ballistic GNRs with effective zigzag-edge conduction. A tight-binding model calculation confirms conductance quantization corresponding to zigzag-edge conduction even for arbitrary GNR orientation. Valley-symmetry conservation is further confirmed by intrinsic conductance interference with a preserved Berry phase of pi in a graphene-based Aharonov-Bohm(AB) ring preparedby similar dualgating. This top-down approach for gate-defined carrier guiding in ballistic graphene is of particular relevance in the efforts towards efficient and promising valleytronic applications.112013sciescopu
The D-SPECT SH reconstruction protocol: improved quantification of small left ventricle volumes.
No full textBACKGROUND
Due to spatial resolution limitations, conventional NaI-SPECT typically overestimates the left ventricular (LV) ejection fraction (EF) in patients with small LV volumes. The purpose of this study was to explore the clinical application value of the small heart (SH) reconstruction protocol embedded in the postprocessing procedure of D-SPECT.
METHODS
We retrospectively analyzed patients who undergo both D-SPECT and echocardiography (Echo) within one week. Patients with small LV volume were defined as those with a rest end-systolic volume (rESV) ≤ 25 mL and underwent reconstruction using the standard (SD) reconstruction protocol. The SH protocol was deemed successful in correcting the LVEF value if it decreased by 5% or more compared to the SD protocol. The ROC curve was used to calculate the optimal cutoff value of the SH protocol. LVEF, ESV and EDV were computed with SD and SH, respectively. Echo was performed as a reference, and Echo-LVEF, ESV, and EDV were calculated using the Teichholz formula. One-way ANOVA was used to compare these parameters among the three groups.
RESULTS
The final study included 209 patients (73.21% female, age 67.34 ± 7.85 years). Compared with the SD protocol, the SH protocol significantly decreased LVEF (67.43 ± 7.38% vs. 71.30 ± 7.61%, p 17 mL (AUC = 0.651, sensitivity = 78.43%, specificity = 45.57%, p = 0.001). In the subgroup of rESV > 17 mL, there was no significant difference in LVEF (61.84 ± 4.67% vs. 62.83 ± 2.85%, p = 0.481) between the SH protocol and Echo, and no significant difference was observed in rESV (26.92 ± 3.25 mL vs. 27.94 ± 7.96 mL, p = 0.60) between the SH protocol and Echo.
CONCLUSION
This pilot study demonstrated that the SH reconstruction protocol was able to effectively correct the overestimation of LVEF in patients with small LV volumes. Particularly, in the rESV > 17 mL subgroup, the time and computing power waste could be reduced while still ensuring the accuracy of the LVEF value and image quality
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SH-CRAN: hierarchical framework to support mobile big data computing in a secure manner
No full textThe heterogeneous cloud radio access network (H-CRAN) has been emerging as a cost-effective solution supporting huge volumes of mobile traffic in the big data era. This paper investigates potential security challenges on H-CRAN and analyzes their likelihoods and difficulty levels. Typically, the security threats in H-CRAN can be categorized into three groups, i.e., security threats towards remote radio heads (RRHs), those towards the radio cloud infrastructure and towards backhaul networks. To overcome challenges made by the security threats, we propose a hierarchical security framework called Secure H-CRAN (SH-CRAN) to protect the H-CRAN system against the potential threats. Specifically, the architecture of SH-CRAN contains three logically independent secure domains (SDs), which are the SDs of radio cloud infrastructure, RRHs and backhauls. The notable merits of SH-CRAN include two aspects: (i) the proposed framework is able to provide security assurance for the evolving H-CRAN system, and (ii) the impacts of any failure are limited in one specific component of H-CRAN. The proposed SH-CRAN can be regarded as the basis of the future security mechanisms of mobile bag data computing
Cloning and characterization of a shrimp clip domain serine protease homolog (c-SPH) as a cell adhesion molecule.
No full textChanges of white blood cell, immunosuppressive acidic protein, and interleukin-2 receptor after open heart surgery.
No full textCarpinus omeiensis Hu & Fang
No full text26. Carpinus omeiensis Hu & Fang Acta Phytotaxonomica Sinica 9: 296 (Hu 1964). – Type: China, Sichuan, Mount Omei [Éméi Shān], Dashiaochenfeng, 1900 m a.s.l., 7 Oct. 1957, K.H. Yang [Yang Kuang-Hway, 杨光辉] 57490 (lecto-, designated here: PE00021939!; isolecto-: IBSC0368104, KUN0590785!, NAS00070308, PE00818214!). – Additional type material: China, Guizhou, Teking Hsien, Yaimenko, 1200 m a.s.l., in dense forest on slope, 15 Aug. 1959, North Kweichow Exped. [黔北队] 1631 (para-: KUN0590783!, NAS00070309!, PE00818217!, PE00818218!).Published as part of Holstein, Norbert & Weigend, Maximilian, 2017, No taxon left behind? - a critical taxonomic checklist of Carpinus and Ostrya (Coryloideae, Betulaceae), pp. 1-52 in European Journal of Taxonomy 375 on page 20, DOI: 10.5852/ejt.2017.375, http://zenodo.org/record/383854
Tracking control of uncertain Euler-Lagrange systems with finite-time convergence
No full textAbstract not available.Qinglei Hu, Bing Xiao and Peng Sh
Wellesly Sh. W. to Mr. James Meredith (2 October 1962)
No full textSigned by Wellesly Sh. W.https://egrove.olemiss.edu/mercorr_pro/1531/thumbnail.jp
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