Calibration of shielded microwave probes using bulk dielectrics

A stripline-type near-field microwave probe is microfabricated for microwave impedance microscopy. Unlike the poorly shielded coplanar probe that senses the sample tens of microns away, the stripline structure removes the stray fields from the cantilever body and localizes the interaction only around the focused-ion beam deposited Pt tip. The approaching curve of an oscillating tip toward bulk dielectrics can be quantitatively simulated and fitted to the finite-element analysis result. The peak signal of the approaching curve is a measure of the sample dielectric constant and can be used to study unknown bulk materials.Comment: 10 pages, 3 figure

Experimental study of the normal zone propagation velocity in double-layer 2G-HTS wires by thermal and electrical methods

The Normal Zone Propagation Velocity (NZPV) of a double-layer second generation (2G) high temperature superconducting (HTS) wire manufactured by American Superconductor has been measured by electrical and thermal methods, and the results have been compared and discussed. The NZPV values determined by the voltage traces are ranging from 3.8 mm/s at 0.4 Ic to 19.2 mm/s at 0.9 Ic; while from 5.9 mm/s to 18.3 mm/s by the temperature traces. NZPV determined by these two approaches agrees well with each other. Also, NZPV of double-layer YBCO tape is close to that of conventional single-layer superconducting tape.This work was supported in part by the EPSRC under Grant NMZF/064.This is the accepted manuscript. The final version is available from IEEE at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6963291&sortType%3Dasc_p_Sequence%26filter%3DAND%28p_IS_Number%3A6353170%29%26rowsPerPage%3D50

Three-jet cross sections in hadron-hadron collisions at next-to-leading order

We present a new QCD event generator for hadron collider which can calculate one-, two- and three-jet cross sections at next-to-leading order accuracy. In this letter we study the transverse energy spectrum of three-jet hadronic events using the kT algorithm. We show that the next-to-leading order correction significantly reduces the renormalization and factorization scale dependence of the three-jet cross section.Comment: 4 pages, 4 figures, REVTEX

Modeling of a Cantilever-Based Near-Field Scanning Microwave Microscope

We present a detailed modeling and characterization of our scalable microwave nanoprobe, which is a micro-fabricated cantilever-based scanning microwave probe with separated excitation and sensing electrodes. Using finite-element analysis, the tip-sample interaction is modeled as small impedance changes between the tip electrode and the ground at our working frequencies near 1GHz. The equivalent lumped elements of the cantilever can be determined by transmission line simulation of the matching network, which routes the cantilever signals to 50 Ohm feed lines. In the microwave electronics, the background common-mode signal is cancelled before the amplifier stage so that high sensitivity (below 1 atto-Farad capacitance changes) is obtained. Experimental characterization of the microwave probes was performed on ion-implanted Si wafers and patterned semiconductor samples. Pure electrical or topographical signals can be realized using different reflection modes of the probe.Comment: 7 figure

Microwave imaging of mesoscopic percolating network in a manganite thin film

Many unusual behaviors in complex oxides are deeply associated with the spontaneous emergence of microscopic phase separation. Depending on the underlying mechanism, the competing phases can form ordered or random patterns at vastly different length scales. Using a microwave impedance microscope, we observed an orientation-ordered percolating network in strained Nd0.5Sr0.5MnO3 thin films with a large period of 100 nm. The filamentary metallic domains align preferentially along certain crystal axes of the substrate, suggesting the anisotropic elastic strain as the key interaction in this system. The local impedance maps provide microscopic electrical information of the hysteretic behavior in strained thin film manganites, suggesting close connection between the glassy order and the colossal magnetoresistance effects at low temperatures.Comment: 4 pages,4 figure

On the Kinetic Roughening in Polymer Film Growth by Vapor Deposition

This is a Comment on a recent publication: Y.-P. Zhao et al., Phys. Rev. Lett. 85, 3229 (2000). In the Letter, the authors report on an experimental investigation of polymeric (p-xylene) thin film growth and propose a new universality class not previously known. Here, we point out that the critical exponents reported in the Letter are consistent with the critical exponents of Das Sarma-Tamborenea growth model.Comment: 2 pages, 1 figure include

iTRAQ proteomics analysis reveals that PI3K is highly associated with bupivacaine-induced neurotoxicity pathways

Bupivacaine, a commonly used local anesthetic, has potential neurotoxicity through diverse signaling pathways. However, the key mechanism of bupivacaine-induced neurotoxicity remains unclear. Cultured human SH-SY5Y neuroblastoma cells were treated (bupivacaine) or untreated (control) with bupivacaine for 24 h. Compared to the control group, bupivacaine significantly increased cyto-inhibition, cellular reactive oxygen species, DNA damage, mitochondrial injury, apoptosis (increased TUNEL-positive cells, cleaved caspase 3, and Bcl-2/Bax), and activated autophagy (enhanced LC3II/LC3I ratio). To explore changes in protein expression and intercommunication among the pathways involved in bupivacaine-induced neurotoxicity, an 8-plex iTRAQ proteomic technique and bioinformatics analysis were performed. Compared to the control group, 241 differentially expressed proteins were identified, of which, 145 were up-regulated and 96 were down-regulated. Bioinformatics analysis of the cross-talk between the significant proteins with altered expression in bupivacaine-induced neurotoxicity indicated that phosphatidyl-3-kinase (PI3K) was the most frequently targeted protein in each of the interactions. We further confirmed these results by determining the downstream targets of the identified signaling pathways (PI3K, Akt, FoxO1, Erk, and JNK). In conclusion, our study demonstrated that PI3K may play a central role in contacting and regulating the signaling pathways that contribute to bupivacaine-induced neurotoxicity.postprin

Rhymes: a shared virtual memory system for non-coherent tiled many-core architectures

The rising core count per processor is pushing chip complexity to a level that hardware-based cache coherency protocols become too hard and costly to scale. We need new designs of many-core hardware and software other than traditional technologies to keep up with the ever-increasing scalability demands. The Intel Single-chip Cloud Computer (SCC) is a recent research processor exemplifying a new cluster-on-chip architecture which promotes a software-oriented approach instead of hardware support to implementing shared memory coherence. This paper presents a shared virtual memory (SVM) system, dubbed Rhymes, tailored to such a new processor kind of non-coherent and hybrid memory architectures. Rhymes features a two-way cache coherence protocol to enforce release consistency for pages allocated in shared physical memory (SPM) and scope consistency for pages in per-core private memory. It also supports page remapping on a per-core basis to boost data locality. We implement Rhymes on the SCC port of the Barrelfish OS. Experimental results show that our SVM outperforms the pure SPM approach used by Intel's software managed coherence (SMC) library by up to 12 times, with superlinear speedups (due to L2 cache effect) noted for applications with strong data reuse patterns.published_or_final_versio