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Fully homomorphic encryption (FHE) has been regarded as the holy grail of cryptography and supports meaningful computations on encrypted data. Recently, Kumer et al. proposed a symmetric FHE scheme based on the Euler theorem. However, we illustrate in the paper that the secret key can be recovered from the homomorphic computation key and only a pair of known plaintext/ciphertext by computing the greatest common divisor with the Euclidean algorithm. Our observations are well supported by the numerical experiments on the suggested parameters. Furthermore, an improvement in the scheme is presented. We mimic Dijk et al.'s idea to illustrate that the improvement can be reduced to the approximate greatest common divisor (AGCD) problem. Several known attacks, including the proposal in this paper, are also examined.

Plasmon lasers can support ultrasmall mode confinement and ultrafast dynamics with device feature sizes below the diffraction limit. At present in the single visible light frequency, the optical gain method of constraint SPP on metal nanowires structure reported less. We design the gold nanowire array structure, consisting of PMMA and R6G dye molecules as gain, by 488 nm pump in the middle of the nanowires position for wide range of light, use symmetry broken overcome that momentum does not match the photonic and SPP energy conversion. Theoretical analysis shows that dyes provide coherent optical feedback, resulting in nanowires face will observe laser properties of surface plasmons. Feature analysis: the incident light and pump joint strength is greater than the sum of strength which is the incident light, pump respectively. Under the effect of dye molecules gain effective, length of SPP transmission can increase 1 µm. The results achieved in a single optical frequency of stimulated radiation, application of dye optical gain can achieve continuous gain effect. This is for the future development of plasma amplifier and the wavelength laser. Keywords: SPP, Stimulated radiation, Gold nanowires array, Dye molecules

Lasers are nowadays widely used in industry, in hospitals and in many devices that we have at home. Random laser development is challenging given its high threshold and low integration. Surface plasmon polariton (SPP) can improve random laser characteristics because of its ability to control diffraction. In this study, we establish a random laser structural model with silicon-based parcel GaN nanowires. The GaN nanowire gain and enhanced surface plasmon increase population inversion level. Our laser model is based on random particle scattering feedback mechanism, nanowire use, and surface plasmon enhancement effect, which causes stochastic laser emergence. Analysis shows that the SPP mode and nanowire waveguides coupled in the dielectric layer of low refractive index can store light energy like a capacitor under low refractive index clearance. The waveguide mode field area and limiting factors show that the modeled laser can achieve sub-wavelength constraints of the output light field. We also investigate emergent laser performance for a more limited light field capacity and lower threshold. Keywords: Random laser, Surface plasmon polariton, Feedback mechanism, Low threshold, Subwavelength constraints

Theoretical analysis in this paper indicates that the accuracy of a silicon piezoresistive pressure sensor is mainly affected by thermal drift, and varies nonlinearly with the temperature. Here, a smart temperature compensation system to reduce its effect on accuracy is proposed. Firstly, an effective conditioning circuit for signal processing and data acquisition is designed. The hardware to implement the system is fabricated. Then, a program is developed on LabVIEW which incorporates an extreme learning machine (ELM) as the calibration algorithm for the pressure drift. The implementation of the algorithm was ported to a micro-control unit (MCU) after calibration in the computer. Practical pressure measurement experiments are carried out to verify the system’s performance. The temperature compensation is solved in the interval from −40 to 85 °C. The compensated sensor is aimed at providing pressure measurement in oil-gas pipelines. Compared with other algorithms, ELM acquires higher accuracy and is more suitable for batch compensation because of its higher generalization and faster learning speed. The accuracy, linearity, zero temperature coefficient and sensitivity temperature coefficient of the tested sensor are 2.57% FS, 2.49% FS, 8.1 × 10−5/°C and 29.5 × 10−5/°C before compensation, and are improved to 0.13%FS, 0.15%FS, 1.17 × 10−5/°C and 2.1 × 10−5/°C respectively, after compensation. The experimental results demonstrate that the proposed system is valid for the temperature compensation and high accuracy requirement of the sensor.

Ahighly sensitive electrochemical aptasensor is developed for the quantification of human a-thrombin (TB), where the response signal is amplified through the recycling of a functional DNA architecture (A1-TB-A2) driven by hairpin strand displacement. This DNA architecture is formed by the proximal binding of TB with two affinity strands (A1 and A2) encoding specific TB aptamer. Only in this case can the unpaired segments cooperatively hybridize with a recognition strand (RS) confined in a Watson-Crick and Hoogsteen triplex-helix (TH), along with the releasing of a DNA hairpin 1 (H1). Upon addition of another hairpin 2 (H2), the complementary base pairing of RS and H2 accelerates the repeated liberation and recycling of A1-TB-A2, bringing H1 releasing and switching into hairpin conformation. As such, the folded H1 with negative charges electrostatically attracts redox mediator [Ru(NH3)6]3+ to produce significantly enhanced current signal. After incubated with Nt.BstNBI, the folded H1 is cleaved at Nt.BstNBI-recognizable nicking site, resulting in decrease of electrostatic attraction to [Ru(NH3)6]3+. The electrochemical response dependent on TB is greatly amplified. Via rational integration of a protein-responsive DNA architecture recycling and enzyme-nicked amplification, this electrochemical strategy is highly specific and sensitive to TB with a limit of detection down to 32 fM, which would be potential to monitor diverse biomolecules. [ABSTRACT FROM AUTHOR]

Based on a cascade dual-signal enhancement strategy by integrating exonuclease III (Exo III)-assisted target-recycling (EATR) with rolling circle amplification (RCA), a highly sensitive electrochemical biosensor was developed for the detection of target DNA (tDNA), a kind of Alzheimer's disease biomarkers. When tDNA was hybridized with hairpin DNA (hDNA) previously modified in the electrode surface by Au-SH bond, the subsequent introduction of Exo III triggered EATR through cleaving hDNA, releasing tDNA and further hybridizing with other hDNA. After repeated recycling, the remained DNA (rDNA) fragments of hDNA as initiators of RCA were extended, generating numerous copies of G-rich base sequence. The presence of hemin resulted in the in situ assembly of multiple hemin/G-quarduplex structures in the resultant electrode surface, which were acted as both label-free redox probes and mimicking peroxidase catalysts for the electrochemical signal readout and amplification, producing significantly enhanced electrochemical response dependent on tDNA. Thus, the developed biosensor exhibited ultrahigh sensitivity with a limit of detection of 3.3 aM. By combining EATR with subsequent RCA, the cascade dual-signal amplification strategy would be promising and potential in biological analysis and clinical diagnosis. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) laser-induced photothermal ablation (PTA) therapy has great potential to revolutionize conventional therapeutic approaches for cancers, and a prerequisite is to obtain biocompatible and efficient photothermal agents. Herein, we have developed hydrophilic W[sub 18]O[sub 49] nanowires with average lengths of about 800 nm (abbreviated as W[sub 18]O[sub 49]-800 NWs) as an efficient photothermal agent, which are prepared by the solvothermal synthesis-simultaneous PEGylation/exfoliation/breaking two-step route. These W[sub 18]O[sub 49]-800 NWs exhibit stronger NIR photoabsorption than short nanowires with average lengths of about 50 nm (abbreviated as W[sub 18]O[sub 49]-50 NWs) that are prepared via a solvothermal one-step route. Under irradiation of 980 nm with a safe intensity of 0.72 W cm[sup -2], the aqueous dispersion of W[sub 18]O[sub 49]-800 NWs (1.0 mg mL[sup -1]) exhibits the temperature elevation by 35.2 °C in 5 min; which is a 37.5% increase compared to that (by 25.6 °C) from W[sub 18]O[sub 49]-50 NWs (1.0 mg mL[sup -1]). More importantly, under 980 nm laser irradiation (0.72 W cm[sup -2]) for 10 min, in vivo cancer cells can be efficiently ablated by the photothermal effects of W[sub 18]O[sub 49]-800 NWs. Therefore, these W[sub 18]O[sub 49]-800 NWs can be used as a more efficient and promising photothermal nanoagent for the ablation of cancer cells in vivo. [ABSTRACT FROM AUTHOR]

A highly sensitive electrochemical aptasensor for thrombin detection is developed and demonstrated by using porous platinum nanotubes modified with polyamidoamine dendrimers as nanocarriers and electrocatalysts. The proposed strategy affords a low detection limit of 0.03 pM based on enzyme-based signal amplification. [ABSTRACT FROM AUTHOR]

Surface plasmon polariton (SPP) nanolaser, which can achieve an all-optical circuit, is a major research topic in the field of micro light source. In this study, we examine a novel SPP graphene nanolaser in an optoelectronic integration field. The proposed nanolaser consists of metallic silver, two-dimensional (2D) graphene and high refractive index semiconductor of indium gallium arsenide phosphorus. Compared with other metals, Ag can reduce the threshold and propagation loss. The SPP field, excited by coupling Ag and InGaAsP, can be enhanced by the 2D material of graphene. In the proposed nanolaser, the maximum value of propagation loss is approximately 0.055 dB/μm, and the normalized mode area is constantly less than 0.05, and the best threshold can achieve 3380 cm−1 simultaneously. Meanwhile, the proposed nanolaser can be fabricated by conventional materials and work in optical communication (1550 nm), which can be easily achieved with current nanotechnology. It is also an important method that will be used to overcome the challenges of high speed, miniaturization, and integration in optoelectronic integrated technology. [ABSTRACT FROM AUTHOR]