Angular dependence of low-frequency noise in Al2O3 -based magnetic tunnel junction sensors with conetic alloy

This journal issue contains selected papers from the 2012 International Magnetics (INTERMAG) ConferenceWe demonstrated the noise performances of Al 2O 3-based magnetic tunnel junction sensors (MTJs) in the low-frequency regimes. Conetic alloy Ni 77Fe 14 Cu 5Mo 4 was deposited as both the MTJ pinned layer and free layer because of its superb magnetically soft properties. A rotating magnetic field was employed to investigate the angular dependence of the MTJ low-frequency noise. Hooge parameter was applied for parameterizing the low-frequency noise. The measurement results demonstrate that the Hooge parameters are angular-dependent and they exhibit a linear relation with respect to the angular magnetoresistive susceptibility. It can be also observed that the Hooge parameters possess a higher value when the Conetic MTJs are in the region of antiparallel state. These results indicate that the magnetic fluctuations in the ferromagnetic layers contribute to the low-frequency noise level in Conetic MTJ sensors. © 2012 IEEE.published_or_final_versionThe IEEE International Magnetics Conference (INTERMAG 2012), Vancouver, BC., 7-11 May 2012. In IEEE Transactions on Magnetics, 2012, v. 48 n. 11, p. 3712-371

Interaction of avian infectious bronchitis virus S1 protein with heat shock protein 47

Infectious bronchitis (IB) caused by a coronavirus is an important disease in chickens; it mainly affects respiratory and kidney systems. The IBV-S1 protein is an important structural and functional protein. To identify the interaction between the IBV-S1 proteins and to elucidate the possible involvement of S1 protein in IBV pathogenesis, a chicken kidney cDNA library was screened using a yeast two-hybrid system assay. HSP47, a molecular chaperone protein facilitating the folding and assembly, was found to interact specifically with the S1 protein. The interaction between S1 and HSP47 was verified by colocalization experiment and co-immunoprecipitation of HeLa cell lysates expressing both proteins. The mapping studies localized the critical S1 sequences for this interaction to amino acids 340-470. Based on these results, we speculate that HSP47 is a functional target of infectious bronchitis virus S1 protein in cells. This is the first report demonstrating the interaction of HSP47 with a structural protein of plusstrand RNA viruses, indicating a new drug target for IBV.Key words: S1 protein, HSP47 protein, yeast two-hybrid, co-localization, co-immunoprecipitation, proteinprotein interaction

Hybrid atomistic-coarse-grained treatment of thin-film lubrication. I

A technique that melds an atomistic description of the interfacial region with a coarse-grained description of the far regions of the solid substrates is presented and applied to a two-dimensional model contact consisting of planar solid substrates separated by a monolayer fluid film. The hybrid method yields results in excellent agreement with the “exact” (i.e., fully atomistic) results. The importance of a proper accounting for the elastic response of the substrates, which is reliably and efficiently accomplished through coarse-graining of the far regions, is demonstrated

Probing Spin-Flip Scattering in Ballistic Nanosystems

Because spin-flip length is longer than the electron mean-free path in a metal, past studies of spin-flip scattering are limited to the diffusive regime. We propose to use a magnetic double barrier tunnel junction to study spin-flip scattering in the nanometer sized spacer layer near the ballistic limit. We extract the voltage and temperature dependence of the spin-flip conductance Gs in the spacer layer from magnetoresistance measurements. In addition to spin scattering information including the mean-free path (70 nm) and the spin-flip length (1:0–2:6 m) at 4.2 K, this technique also yields information on the density of states and quantum well resonance in the spacer laye

Design–material transition threshold of ribbon kirigami

\ua9 2024 The AuthorsThe ribbon kirigami pattern has garnered significant attention over the past decade because of its interesting geometric and mechanical properties such as extreme elongation and high ductility, making it a viable choice for various applications such as developing medical devices and flexible electronics. Despite the promising prospects of this type of morphing structure, its deformation mechanism and sensitivity to materials properties and geometric parameters have remained largely unexplored. Here we take a computational approach to studying the deformation process and ductility of a typical ribbon kirigami metastructure. To this end, the deformation process is divided into various stages. We demonstrate the existence of a certain threshold of the process at which the deformation behavior starts to be dominated by the properties of the constituent material, after the initial geometric-design-dominated stages. This turning point, called the design–material transition (DMT) threshold, determines a key limit in the deformation capacity of such metastructures for practical applications. Based on the introduced deformation mechanism, an elongation prediction model is derived for the metastructure, followed by conducting experiments to validate the accuracy of the model. Furthermore, a genetic algorithm and an interior-point method are utilized to develop an efficient algorithm for the optimization of the geometric parameters of the kirigami pattern. We anticipate that the findings of this study open a path to engineering functional kirigami patterns for the design and fabrication of highly ductile shape-shifting structures

Experimental Investigation on the ICCP-SS Technique for Sea-Sand RC Beams

Impressed current cathodic protection (ICCP) is an efficient method to prevent further corrosion of the re-bars, while strengthening structures (SS) by using carbon fiber mesh can help improve the loading capacity of the degraded sea-sand reinforced concrete (RC) structures. This study proposes a new dual-functional method, ICCP-SS, to retrofit the sea-sand RC structures by using the carbon - fiber reinforced cementitious matrix (C-FRCM). The C-FRCM composite, comprised of carbon fiber mesh and inorganic cementitious material, is both the anodic material in the ICCP process as well as the structural strengthening material. This paper presents an experimental program consisting of 11 simply supported beams, 10 of them casted by simulated sea-sand and subjected to accelerated corrosion process for 130 days. The specimens casted by sea-sand were afterwards bonded with C-FRCM composite, treated by ICCP for 130 days, and finally tested. In this study, the flexure strength of the beams, the deflection and curvature of the specimens, as well as the strain and the open circuit potential of re-bars are obtained and used to assess the performance of the repaired specimens. The proposed technique has been shown to be effective in retarding the corrosion of re-bars and recovering the loading capacity of the corroded specimens, which should be beneficial for the durability of sea-sand RC structures

Smear microscopy and culture conversion rates among smear positive pulmonary tuberculosis patients by HIV status in Dar es Salaam, Tanzania

Tanzania ranks 15th among the world's 22 countries with the largest tuberculosis burden and tuberculosis has continued to be among the major public health problems in the country. Limited data, especially in patients co infected with HIV, are available to predict the duration of time required for a smear positive pulmonary tuberculosis patient to achieve sputum conversion after starting effective treatment. In this study we assessed the sputum smear and culture conversion rates among HIV positive and HIV negative smear positive pulmonary tuberculosis patients in Dar es Salaam The study was a prospective cohort study which lasted for nine months, from April to December 2008 A total of 502 smear positive pulmonary tuberculosis patients were recruited. HIV test results were obtained for 498 patients, of which 33.7% were HIV positive. After two weeks of treatment the conversion rate by standard sputum microscopy was higher in HIV positive(72.8%) than HIV negative(63.3%) patients by univariate analysis(P = 0.046), but not in multivariate analysis. Also after two weeks of treatment the conversion rate by fluorescence microscopy was higher in HIV positive (72.8%) than in HIV negative(63.2%) patients by univariate analysis (P = 0.043) but not in the multivariate analysis. The conversion rates by both methods during the rest of the treatment period (8, 12, and 20 weeks) were not significantly different between HIV positive and HIV negative patients.With regards to culture, the conversion rate during the whole period of the treatment (2, 8, 12 and 20 weeks) were not significantly different between HIV positive and HIV negative patients.\ud Conversion rates of standard smear microscopy, fluorescence microscopy and culture did not differ between HIV positive and HIV negative pulmonary tuberculosis patients

Self-repairing interphase reconstructed in each cycle for highly reversible aqueous zinc batteries

Aqueous zinc (Zn) chemistry features intrinsic safety, but suffers from severe irreversibility, as exemplified by low Coulombic efficiency, sustained water consumption and dendrite growth, which hampers practical applications of rechargeable Zn batteries. Herein, we report a highly reversible aqueous Zn battery in which the graphitic carbon nitride quantum dots additive serves as fast colloid ion carriers and assists the construction of a dynamic & self-repairing protective interphase. This real-time assembled interphase enables an ion-sieving effect and is found actively regenerate in each battery cycle, in effect endowing the system with single Zn2+ conduction and constant conformal integrality, executing timely adaption of Zn deposition, thus retaining sustainable long-term protective effect. In consequence, dendrite-free Zn plating/stripping at ~99.6% Coulombic efficiency for 200 cycles, steady charge-discharge for 1200 h, and impressive cyclability (61.2% retention for 500 cycles in a Zn | |MnO2 full battery, 73.2% retention for 500 cycles in a Zn | |V2O5 full battery and 93.5% retention for 3000 cycles in a Zn | |VOPO4 full battery) are achieved, which defines a general pathway to challenge Lithium in all low-cost, large-scale applications