The effect of the polarizations of two counter-propagating relativistic laser pulses interacting with subwavelength thin solid-density foil is investigated. Three-dimensional particle-in-cell simulations and analytical modelling show that the interaction and resulting transverse instability depend strongly on the polarization directions as well as the intensity distribution of the resultant light field in the foil. The left- and right-handed circularly polarized laser pair with the same phase at the common focal spot in the ultrathin foil leads to the strongest distortion of the foil. The fastest growing mode and maximum growth rate depend mainly on the laser intensity. For all polarization and phase-difference combinations, the instability is weakest when the two laser pulses are exactly out of phase at the common focusing point in the foil.

With the escalating laser peak power, modulating and detecting the intensity, duration, phase and polarization of ultra-intense laser pulses progressively becomes increasingly arduous due to the limited damage thresholds of conventional optical components. In particular, the generation and detection of ultra-intense vortex lasers pose great challenges for current laser technologies, which has limited the widely potential applications of relativistic vortex lasers in various domains. In this study, we propose to reconstruct the vortex phase and generate and amplify the relativistic vortex lasers via surface plasma holograms (SPHs). By interfering with the object laser and reference laser, SPHs are formed on the target and the phase of the interfering laser is imprinted through the modulation of surface plasma density. In particular, using the quadrature phase-shift interference, the vortex phase of the object laser can be well reconstructed. The generated vortex lasers can be focused and enhanced further by one order of magnitude, up to $1.7\times {10}^{21}$ W/cm${}^2$, which has been demonstrated by full three-dimensional particle-in-cell simulations. For the first time, we provide a practical way to detect the phase of relativistic vortex lasers, which can be applied in large 1–10 PW laser facilities. This will promote future experimental research of vortex-laser–plasma interaction and open a new avenue of plasma optics in the ultra-relativistic regime.

In the present study, we analysed the effects of SNP rs174547 (T/C) in the fatty acid desaturase 1 (FADS1) gene on long-chain PUFA levels. Four databases were searched to retrieve related literature with keywords such as fatty acid (FA), SNP, FADS1 and rs174547. A meta-analysis of the data was performed using Stata12.0 software, including summary statistics, test for heterogeneity, evaluation of publication bias, subgroup analysis and sensitivity analysis. The associations between rs174547 in FADS1 and seven types of FA, and Δ-5 (D5D) and Δ-6 fatty acid desaturase (D6D) activity were assessed based on the pooled results from eleven papers. A total of 3713 individuals (1529 TT and 2184 TC + CC) were included. The results demonstrated that minor C allele carriers of rs174547 had higher linoleic acid (LA; P < 0·001) and α-linolenic acid (P = 0·020) levels, lower γ-linolenic acid (GLA; P = 0·001) and arachidonic acid (P = 0·024) levels, and lower D5D (P = 0·005) and D6D (P = 0·004) activities than the TT genotype group. Stratification analysis showed that minor C allele carriers of rs174547 had higher LA and lower GLA levels and lower D6D activities in plasma (LA, P < 0·001; GLA, P < 0·001; D6D activity, P < 0·001) samples and in Asian populations (LA, P < 0·001; GLA, P = 0·001; D6D activity, P = 0·001) than the TT genotype group. In conclusion, minor C allele carriers of the SNP rs174547 were associated with decreased activity of D5D and D6D.

Magnetic iron oxide nanoparticles (MIONPs) are particularly attractive in biosensor, antibacterial activity, targeted drug delivery, cell separation, magnetic resonance imaging tumor magnetic hyperthermia, and so on because of their particular properties including superparamagnetic behavior, low toxicity, biocompatibility, etc. Although many methods had been developed to produce MIONPs, some challenges such as severe agglomeration, serious oxidation, and irregular size are still faced in the synthesis of MIONPs. Thus, various strategies had been developed for the surface modification of MIONPs to improve the characteristics of them and obtain multifunctional MIONPs, which will widen the applicational scopes of them. Therefore, the processes, mechanisms, advances, advantages, and disadvantages of six main approaches for the synthesis of MIONPs; surface modification of MIONPs with inorganic materials, organic molecules, and polymer molecules; applications of MIONPs or modified MIONPs; the technical challenges of synthesizing MIONPs; and their limitations in biomedical applications were described in this review to provide the theoretical and technological guidance for their future applications.

The potential use of onboard vision sensors (e.g., cameras) has long been recognized for the Sense and Avoid (SAA) of unmanned aerial vehicles (UAVs), especially for micro UAVs with limited payload capacity. However, vision-based SAA for UAVs is extremely challenging because vision sensors usually have limitations on accurate distance information measuring. In this paper, we propose a monocular vision-based UAV SAA approach. Within the approach, the host UAV can accurately and efficiently avoid a noncooperative intruder only through angle measurements and perform maneuvers for optimal tradeoff among target motion estimation, intruder avoidance, and trajectory tracking. We realize this feature by explicitly integrating a target tracking filter into a nonlinear model predictive controller. The effectiveness of the proposed approach is verified through extensive simulations.

Let ${\mathcal{A}}=\{a_{1}<a_{2}<\cdots \,\}$ be a set of nonnegative integers. Put $D({\mathcal{A}})=\gcd \{a_{k+1}-a_{k}:k=1,2,\ldots \}$. The set ${\mathcal{A}}$ is an asymptotic basis if there exists $h$ such that every sufficiently large integer is a sum of at most $h$ (not necessarily distinct) elements of ${\mathcal{A}}$. We prove that if the difference of consecutive integers of ${\mathcal{A}}$ is bounded, then ${\mathcal{A}}$ is an asymptotic basis if and only if there exists an integer $a\in {\mathcal{A}}$ such that $(a,D({\mathcal{A}}))=1$.

Discovery of well-preserved specimens from the Nanba section in Yiyang, Hunan Province, in combination with a literature review, enabled us to re-evaluate and revise the graptolite genus Ancoragraptus. This is a genus of biradiate, multiramous anisograptids with horizontal to reclined rhabdosomes and free lower part of the metasicula and slightly isolated autothecal apertures. According to the revised definition, two species are included in Ancoragraptus, i.e., Ancoragraptus bulmani (Spjeldnæs, 1963) and Ancoragraptus psigraptoides Cho, Kim, and Jin, 2009. It is the first time that A. bulmani has been reported from China. The occurrences of Ancoragraptus reported worldwide are reviewed in the present study and found to be restricted to the lower upper Tremadocian. The restriction of Ancoragraptus in stratigraphical distribution makes it a taxon with a high potential for precise biostratigraphical correlation at both regional and global scale.

How prebiotic metabolic pathways could have formed is an essential question for the origins of life on early Earth. From the abiogenetic point of view, the emergence of primordial metabolism may be postulated as a continuum from Earth's geochemical processes to chemoautotrophic biochemical procedures on mineral surfaces. In the present study, we examined in detail the reversible amination of α-ketoglutarate on UV-irradiated ZnS particles under variable reaction conditions such as pH, temperature, hole scavenger species and concentrations, and different amino acids. It was observed that the reductive amination of α-ketoglutarate and the oxidative amination of glutamate were both effectively performed on ZnS surfaces in the presence and absence of a hole scavenger, respectively. Accordingly, a photocatalytic mechanism was proposed. The reversible photochemical reaction was more efficient under basic conditions but independent of temperature in the range of 30–60 °C. SO32− was more effective than S2− as the hole scavenger. Finally, we extended the glutamate dehydrogenase-like chemistry to a set of other α-amino acids and their corresponding α-oxo acids and found that hydrophobic amino acid side chains were more conducive to the reversible redox reactions. Since the experimental conditions are believed to have been prevalent in shallow water hydrothermal vent systems of early Earth, the results of this work not only suggest that the ZnS-assisted photochemical reaction can regulate the redox equilibrium between α-amino acids and α-oxo acids, but also provide a model of how prebiotic metabolic homoeostasis could have been developed and regulated. These findings can advance our understanding of the establishment of archaic non-enzymatic metabolic systems and the origins of autotrophy.

Silica-on-silicon label-free biosensor with PMMA (Poly(methyl methacrylate), as the functional layer was designed, fabricated, and tested. The sensor is based on Fabry Perot (FP) interferometry. Specific binding was tested with Human IgG and anti-Human IgG. Non-specific binding was tested with Human IgG and Mouse IgG. The testing results show that the sensor has a nearly six-fold greater response upon specific binding than upon non specific binding. Thermal and long term stability experiments show that the sensor is insensitive to the environment fluctuation. The fabrication process is simple without special surface treatment. In addition, this biosensor is inexpensive and easy to use.

Based on Gauss’ principle of least constraint and Nosé-Hoover thermostat formulation, the numerical algorithms for molecular dynamics simulation are developed to investigate the properties of grain boundary in transition metals Fe and Ni at finite temperature. By the appropriate choice of heat bath parameter, a constant temperature version can be realized. A series of parameters are introduced to describe quantitatively the crystallographic characteristic and the distortion of structure unit. The results indicate the applicability of the calculation mode developed by us and reveal the feature of the atomic structure of grain boundary at finite temperature.