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We developed a reusable surface-amplified nanobiosensor for monitoring airborne viruses with a sub-PFU/mL level detection limit. Here, sandwich structures consisted of magnetic particles functionalized with antibodies, target viruses, and alkaline phosphatases (ALPs) were formed, and they were magnetically concentrated on Ni patterns near an electrochemical sensor transducer. Then, the electrical signals from electrochemical markers generated by ALPs were measured with the sensor transducer, enabling highly-sensitive virus detection. The sandwich structures in the used sensor chip could be removed by applying an external magnetic field, and we could reuse the sensor transducer chip. As a proof of concepts, the repeated detection of airborne influenza virus using a single sensor chip was demonstrated with a detection limit down to a sub-PFU/mL level. Using a single reusable sensor transducer chip, the hemagglutinin (HA) of influenza A (H1N1) virus with different concentrations were measured down to 10 aM level. Importantly, our sensor chip exhibited reliable sensing signals even after more than 18 times of the repeated HA sensing measurements. Furthermore, airborne influenza viruses collected from the air could be measured down to 0.01 PFU/mL level. Interestingly, the detailed quantitative analysis of the measurement results revealed the degradation of HA proteins on the viruses after the air exposure. Considering the ultrasensitivity and reusability of our sensors, it can provide a powerful tool to help preventing epidemics by airborne pathogens in the future.

Homomorphic authenticated encryption allows implicit computation on plaintexts using corresponding ciphertexts without losing privacy, and provides authenticity of the computation and the resultant plaintext of the computation when performing a decryption. However, due to its special functionality, the security notions of the homomorphic authenticated encryption is somewhat complicated and the construction of fully homomorphic authenticated encryption has never been given. In this work, we propose a new security notion and the first construction of fully homomorphic authenticated encryption. Our new security notion is a unified definition for data privacy and authenticity of homomorphic authenticated encryption. Moreover, our security notion is simpler and stronger than the previous ones. To realize our new security notion, we also suggest a construction of fully homomorphic authenticated encryption via generic construction. We combine a fully homomorphic encryption and two homomorphic authenticators, one fully homomorphic and one OR-homomorphic, to construct a fully homomorphic authenticated encryption that satisfies our security notion. Our construction requires its fully homomorphic encryption to be indistinguishable under chosen plaintext attacks and its homomorphic authenticators to be unforgeable under selectively chosen plaintext queries. Our construction also supports multiple datasets and amortized efficiency. For efficiency, we also construct a multi-dataset fully homomorphic authenticator scheme, which is a variant of the first fully homomorphic signature scheme. Our multi-dataset fully homomorphic authenticator scheme satisfies the security requirement of our generic construction above and supports amortized efficiency.

We mapped the nanoscale reduction of resistivity and noise source activities induced by metallic single walled carbon nanotubes (m-SWCNTs) embedded in gold thin films. In this method, current and noise maps of m-SWCNTs/gold hybrid thin films were recorded using a conducting probe in contact with the surface, and the maps were utilized to estimate the nanoscale variation of resistivity (ρ) and the density distribution of noise sources (Neff) generating electrical noises in the hybrid thin film. The m-SWCNTs/gold hybrid thin films with a 5 nm thick gold layer exhibited 300% improved conductivity compared to that of pristine gold thin films. Additionally, the regions with embedded m-SWCNTs showed significantly reduced noise source densities compared with pristine gold film regions. These results clearly show that embedded m-SWCNTs improve the conductivity and reduce electrical noises of metallic electrodes. Interestingly, we observed that the ρ and the Neff on both m-SWCNTs/gold hybrid and pristine gold regions exhibited a scaling behavior of ρ ∝ Neff0.5, implying the hopping charge conduction and noise characteristics of m-SWCNTs/gold hybrid films. Our works can be a useful guideline for the development of high performance electrodes based on CNTs.

Objectives The aim of this study was to evaluate the effect of ticagrelor versus clopidogrel on left ventricular (LV) remodeling after reperfusion of ST-segment elevation myocardial infarction (STEMI) in humans. Background Animal studies have demonstrated that ticagrelor compared with clopidogrel better protects myocardium against reperfusion injury and improves remodeling after myocardial infarction. Methods In this investigator-initiated, randomized, open-label, assessor-blinded trial performed at 10 centers in Korea, patients were enrolled if they had naive STEMI successfully treated with primary percutaneous coronary intervention (PCI) and at least 6-month planned duration of dual-antiplatelet treatment. The coprimary endpoints were LV remodeling index (LVRI) (a relative change of LV end-diastolic volume) measured on 3-dimensional echocardiography and N-terminal pro–B-type natriuretic peptide level at 6 months. Results Among initially enrolled patients with STEMI (n = 336), 139 in each group completed the study. LVRI at 6 months was numerically lower with ticagrelor versus clopidogrel (0.6 ± 18.6% vs. 4.5 ± 16.5%; p = 0.095). Ticagrelor significantly reduced the 6-month level of N-terminal pro–B-type natriuretic peptide (173 ± 141 pg/ml vs. 289 ± 585 pg/ml; p = 0.028). These differences were prominent in patients with pre-PCI TIMI (Thrombolysis In Myocardial Infarction) flow grade 0. By multivariate analysis, ticagrelor versus clopidogrel reduced the risk for positive LV remodeling (LVRI >0%) (odds ratio: 0.56; 95% confidence interval: 0.33 to 0.95; p = 0.030). The LV end-diastolic volume index remained unchanged during ticagrelor treatment (from 54.7 ± 12.2 to 54.2 ± 12.2 ml/m2; p = 0.629), but this value increased over time during clopidogrel treatment (from 54.6 ± 11.3 to 56.4 ± 13.9 ml/m2; p = 0.056) (difference −2.3 ml/m2; 95% confidence interval: −4.8 to 0.2 ml/m2; p = 0.073). Ticagrelor reduced LV end-systolic volume index (from 27.0 ± 8.5 to 24.7 ± 8.4 ml/m2; p Conclusions Ticagrelor was superior to clopidogrel for LV remodeling after reperfusion of STEMI with primary PCI. (High Platelet Inhibition With Ticagrelor to Improve Left Ventricular Remodeling in Patients With ST Segment Elevation Myocardial Infarction [HEALING-AMI]; NCT02224534 )

This paper investigates the performance interference of blockchain services that run on cloud data centers. As the data centers offer shared computing resources to multiple services, the blockchain services can experience performance interference due to the co-located services. We explore the impact of the interference on Fabric performance and develop a new technique to offer performance isolation for Hyperledger Fabric, the most popular blockchain platform. First, we analyze the characteristics of the different components in Hyperledger Fabric and show that Fabric components have different impacts on the performance of Fabric. Then, we present QiOi, component-level performance isolation technique for Hyperledger Fabric. The key idea of QiOi is to dynamically control the CPU scheduling of Fabric components to cope with the performance interference. We implement QiOi as a user-level daemon and evaluate how QiOi mitigates the performance interference of Fabric. The evaluation results demonstrate that QiOi mitigates performance degradation of Fabric by 22% and improves Fabric latency by 2.5 times without sacrificing the performance of co-located services. In addition, we show that QiOi can support different ordering services and chaincodes with negligible overhead to Fabric performance.

A method is developed to directly map nanoscale "noise-source switching" phenomena during the optoelectronic switching of phase-separated polymer nanocomposites of tetrathiafulvalene (TTF) and phenyl-C61 -butyric acid methyl ester (PCBM) molecules dispersed in a polystyrene (PS) matrix. In the method, electrical current and noise maps of the nanocomposite film are recorded using a conducting nanoprobe, enabling the mapping of a conductivity and a noise-source density. The results provide evidence for a repeated modulation in noise sources, a "noise-source switching," in each stage of a switching cycle. Interestingly, when the nanocomposite is "set" by a high bias, insulating PS-rich phases shows a drastic decrease in a noise-source density which becomes lower than that of conducting TTF-PCBM-rich phases. This can be attributed to a trap filling by charge carriers generated from a TTF (donor)-PCBM (acceptor) complex. In addition, when the film is exposed to UV, an optical switching occurs due to chemical reactions which lead to irreversible changes on the noise-source density and conductivity. The method provides a new insight on noise-source activities during the optoelectronic switching of polymer nanocomposites and thus can be a powerful tool for basic noise research and applications in organic memory devices.

An electrical noise is one of the key parameters determining the performance of modern electronic devices. However, it has been extremely difficult, if not impossible, to image localized noise sources or their activities in such devices. We report a “noise spectral imaging” strategy to map the activities of localized noise sources in graphene domains. Using this method, we could quantitatively estimate sheet resistances and noise source densities inside graphene domains, on domain boundaries and on the edge of graphene. The results show high activities of noise sources and large sheet resistance values at the domain boundary and edge of graphene. Additionally, we showed that the top layer in double-layer graphene had lower noises than single-layer graphene. This work provides valuable insights about the electrical noises of graphene. Furthermore, the capability to directly map noise sources in electronic channels can be a major breakthrough in electrical noise research in general.

In the present study, nanoscale wavelength-selective photovoltaic activities in H- and J-aggregates of azo dye-based solar cell films were mapped by wavelength-dependent photoconductive noise microscopy. In this strategy, the local conductivities and charge traps in dye films were mapped by a conducting probe scanning the surface while illuminating the lights with selected wavelengths. We observed the formation of localized domains exhibiting wavelength-dependent photoconductivities. The individual domains could be identified as H- and J-aggregates, which showed dominant photoexcitations at wavelengths of 600 and 450 nm, respectively. Notably, the short-circuit currents Isc and photoconductivities ΔσPC of the film showed power-law dependencies with trap densities under illuminated conditions (NT_L) and the trap density change by the illumination (ΔNT), respectively, like ΔσPC ∝ |ΔNT|1/2 and Isc ∝ NT_L−3/4 for each wavelength illumination. These results revealed the carrier recombination process in cooperation with the traps which could be a major factor determining the performance of solar cells. Significantly, the J-aggregates showed lower trap densities than those of the H-aggregates, resulting in superior solar cell characteristics of the J-aggregates, such as a higher Isc and larger open circuit voltages. Since our method allows mapping the nanoscale photovoltaic activities of solar cell film aggregates, it can be a powerful tool for both basic research and in the application of photoelectronic devices.

International audience; Semiconducting single-walled carbon nanotube-Au (sSWCNT-Au) hybrid films are prepared to build a thermistor device with an adjustable temperature coefficient and show that the embedded sSWCNTs reduce the resistivity and noise source activities in the nanoscale regions of the film. The temperature coefficient of the hybrid films can be adjusted from negative to positive values simply by increasing the deposited Au thickness. Moreover, scanning noise microscopy is utilized to map the nanoscale variation of the resistivity and noise source density on the sSWCNT-Au hybrid films. Interestingly, the map shows that the regions with both sSWCNT and Au exhibit three times lower resistivity and 18 times smaller noise source activities than pristine Au regions, indicating that sSWCNTs embedded in metallic films can significantly reduce the resistivity and electrical noise source activities in the film.