Multi-dimensional cylindrical vector beam (de)multiplexing through cascaded wavelength- and polarization-sensitive metasurfaces.

Cylindrical vector beams (CVBs) exhibit great potential for multiplexing communication, owing to their mode orthogonality and compatibility with conventional wavelength multiplexing techniques. However, the practical application of CVB multiplexing communication faces challenges due to the lack of effective spatial polarization manipulation technologies for (de)multiplexing multi-dimensional physical dimensions of CVBs. Herein, we introduce a wavelength- and polarization-sensitive cascaded phase modulation strategy that utilizes multiple coaxial metasurfaces for multi-dimensional modulation of CVBs. By leveraging the spin-dependent phase modulation mechanism, these metasurfaces enable the independent transformation of the two orthogonal polarization components of CVB modes. Combined with the wavelength sensitivity of Fresnel diffraction in progressive phase modulation, this approach establishes a high-dimensional mapping relationship among CVB modes, wavelengths, spatial positions, and Gaussian fundamental modes, thereby facilitating multi-dimensional (de)multiplexing involving CVB modes and wavelengths. As a proof of concept, we theoretically demonstrate a 9-channel multi-dimensional multiplexing system, successfully achieving joint (de)multiplexing of 3 CVB modes (1, 2, and 3) and 3 wavelengths (1550 nm, 1560 nm, and 1570 nm) with a diffraction efficiency exceeding 80%. Additionally, we show the transmission of 16-QAM signals across 9 channels with the bit-error-rates below 10-5. By combining the integrability of metasurfaces with the high-dimensional wavefront manipulation capabilities of multilevel modulation, our strategy can effectively address the diverse demands of different wavelengths and CVB modes in optical communication.

Forces driving transposable element load variation during Arabidopsis range expansion.

Genetic load refers to the accumulated and potentially life-threatening deleterious mutations in populations. Understanding the mechanisms underlying genetic load variation of transposable element (TE) insertion, a major large-effect mutation, during range expansion is an intriguing question in biology. Here, we used 1,115 global natural accessions of Arabidopsis (Arabidopsis thaliana) to study the driving forces of TE load variation during its range expansion. TE load increased with range expansion, especially in the recently established Yangtze River basin population. Effective population size, which explains 62.0% of the variance in TE load, high transposition rate, and selective sweeps contributed to TE accumulation in the expanded populations. We genetically mapped and identified multiple candidate causal genes and TEs, and revealed the genetic architecture of TE load variation. Overall, this study reveals the variation in TE genetic load during Arabidopsis expansion and highlights the causes of TE load variation from the perspectives of both population genetics and quantitative genetics.

High-order orbital angular momentum mode-based phase shift-keying communication using phase difference modulation.

Orbital angular momentum (OAM) mode offers a promising modulation dimension for high-order shift-keying (SK) communication due to its mode orthogonality. However, the expansion of modulation order through superposing OAM modes is constrained by the mode-field mismatch resulting from the rapidly increased divergence with mode orders. Herein, we address this problem by propose a phase-difference modulation strategy that breaks the limitation of modulation orders via introducing a phase-difference degree of freedom (DoF) beyond OAM modes. Phase-difference modulation exploits the sensitivity of mode interference to phase differences, thereby providing distinct tunable parameters. This enables the generation of a series of codable spatial modes with continuous variation within the same superposed OAM modes by manipulating the interference state. Due to the inherent independence between OAM mode and phase-difference DoF, the number of codable modes increases exponentially, which facilitates establishing ultra-high-order phase shift-keying by discretizing the continuous phase difference and establishing a one-to-one mapping between coding symbols and constructed modes. We show that a phase shift-keying communication link with a modulation order of up to 4 × 104 is achieved by employing only 3 OAM modes (+1, + 2 and +3), and the decode accuracy reaches 99.9%. Since the modulation order is exponentially correlated with the OAM modes and phase differences, the order can be greatly improved by further increasing the superimposed OAM modes, which may provide new insight for high-order OAM-based SK communication.

Identification of Serum Oxylipins Associated with the Development of Coronary Artery Disease: A Nested Case-Control Study.

Coronary artery disease (CAD) is among the leading causes of death globally. The American Heart Association recommends that people should consume more PUFA-rich plant foods to replace SFA-rich ones to lower serum cholesterol and prevent CAD. However, PUFA may be susceptible to oxidation and generate oxidized products such as oxylipins. In this study, we investigated whether the blood oxylipin profile is associated with the risk of developing CAD and whether including identified oxylipins may improve the predictability of CAD risk. We designed a nested case-control study with 77 cases and 148 matched controls from a 10-year follow-up of the Nutrition and Health Survey in a Taiwanese cohort of 720 people aged 50 to 70. A panel of 46 oxylipins was measured for baseline serum samples. We discovered four oxylipins associated with CAD risk. 13-oxo-ODE, which has been previously found in formed plagues, was positively associated with CAD (OR = 5.02, 95%CI = 0.85 to 15.6). PGE2/PGD2, previously shown to increase cardiac output, was inversely associated (OR = 0.16, 95%CI = 0.06 to 0.42). 15-deoxy-PGJ2, with anti-inflammatory and anti-apoptosis effects on cardiomyocytes (OR = 0.26, 95%CI = 0.09 to 0.76), and 5-HETE, which was associated with inflammation (OR = 0.28, 95%CI = 0.10 to 0.78), were also negatively associated as protective factors. Adding these four oxylipins to the traditional risk prediction model significantly improved CAD prediction.

Atomic-layered Pt clusters on S-vacancy rich MoS2-x with high electrocatalytic hydrogen evolution.

Developing suitable supports to maximize the atomic utilization efficiency of platinum group metals is of great significance to hydrogen evolution from water splitting. Herein, we report a fully exposed Pt cluster supported on an S-vacancy rich MoS2-x support (Pt/Sv-MoS2-x) by a facile impregnation method. Pt/Sv-MoS2-x exhibits an outstanding electrochemical HER performance with a low overpotential of 26.6 mV at a current density of 10 mA cm-2, a small Tafel slope of 34.8 mV dec-1 and good durability. Most importantly, the mass activity of Pt is an order of magnitude more active than that of commercial Pt/C at an overpotential of 0.08 V. We attribute this exceptional HER catalytic performance to the fact that platinum and Sv-MoS2-x act in synergy to accelerate the reaction kinetics.

Two-Dimensional Metal Organic Framework Nanosheets as Bifunctional Catalyst for Electrochemical and Photoelectrochemical Water Oxidation.

Electrochemical (EC) and photoelectrochemical (PEC) water splitting represent promising strategies for renewable energy conversion and fuel production and require design of efficient catalysts for the oxygen evolution reaction (OER). Herein, we report the synthesis of two-dimensional (2D) Co-based metal organic framework (Co-MOF) nanosheets and their bifunctional catalytic properties for both EC and PEC OER. Benefiting from the large surface area and abundant isolated metal active sites, the Co-MOF nanosheets exhibited excellent OER activity and stability. The efficient electron-hole generation and separation of the nanosheets, owing to dimensional confinement, contributed to an improved visible light response in PEC OER. This study presents a new strategy to design EC/PEC bifunctional catalyst utilizing unique structural and electronic features of 2D MOF.

Self-Assembly Anisotropic Magnetic Nanowire Films Induced by External Magnetic Field.

Self-assembly generated materials induced by an external magnetic field have attracted considerable interest following the development of nanodevices. However, the fabrication of macroscopic and anisotropic magnetic films at the nanoscale remains a challenge. Here, anisotropic magnetic films are successfully prepared using a solution-based nanowire assembly strategy under a magnetic field. The assembly process is manipulated by changing the thickness of silica shell coated on the surface of magnetic nanowires. The anisotropic magnetic films show highly anisotropic magnetization under different angles of magnetic field and better magnetization properties than that of disordered magnetic films. The well-defined nanowire arrays enable magnetization anisotropic property which may be useful in the magnetic energy conversion technologies and biomedical sciences which lie far beyond those achievable with traditional magnetic materials.

One-step activation of high-graphitization N-doped porous biomass carbon as advanced catalyst for vanadium redox flow battery.

In this paper, we reported a one-step activation strategy to prepare highly graphitized N-doped porous carbon materials (KDC-FAC) derived from biomass, and adopted ferric ammonium citrate (FAC) as active agent. At high temperature, FAC was decomposed into Fe- and NH3-based materials, further increasing graphitization degree, introducing N-containing functional groups and forming porous structure. KDC-FAC has superior electrocatalytic activity and stability towards V2+/V3+ and VO2+/VO2+ redox reactions. High graphitization degree can enhance the conductivity of carbon material, and porous structure is conducive to increase reaction area of vanadium redox couples. Moreover, N-containing functional groups are beneficial to improve the electrode wettability and serve as active sites. The single cell tests demonstrate that KDC-FAC modified cell exhibits good adaptability under high current density and superb stability in cycling test. Compared with pristine cell, the energy efficiency of KDC-FAC modified cell is increased by 9% at 150 mA cm-2. This biomass-derived carbon-based material proposed in our work is expected to be an excellent catalyst for vanadium redox flow battery.

Synthesis of Few-Layer Graphene Sheets from Waste Expanded Polystyrene by Dense Fe Cluster Catalysis.

Graphene sheets have a vast number of potential applications due to their excellent properties. However, poor quality and harsh preparation conditions restrict their application. Here, few-layer graphene (FLG) sheet powder with high quality has been synthesized from waste expanded polystyrene (EPS) at low temperature by dense Fe cluster catalysis. The micron-sized FLG sheets comprising about three layers show high crystallinity and good electrical conductivity that are comparable to those of the shear-exfoliated graphene nanoplatelets. More than 70% carbon yield of FLG sheets from cheap EPS and their safe, controllable synthesis conditions make it easy to expand production. The catalytic formation mechanism of FLG sheets is studied.

Application of porous biomass carbon materials in vanadium redox flow battery.

Porous nano biomass carbon was synthesized by one-step method using scaphium scaphigerum as carbon source and was employed as negative catalyst for vanadium redox flow battery. Potassium ferrate was used to realize synchronous etching, introducing oxygen-containing groups and graphitization of scaphium scaphigerum to obtain porous, oxygen-rich, high-graphization carbon materials (SS-K/Fe). Compared with traditional two-step method, one-step method has advantages of low-time requirement, high efficiency and no pollution. The prepared SS-K/Fe sample has abundant microporous structure, high degree of graphitization and many oxygen-containing groups. The electrochemical test results show that the prepared carbon-based materials exhibit superior electrocatalytic capability for V2+/V3+ redox reaction. The electrode process can be accelerated from three steps including ion diffusion, electrochemical reaction and electron transfer processes, which are due to the enhancement of wetting performance and electrical conductivity, and an increase of effective catalytic area. Compared with pristine cell, the SS-K/Fe modified cell can improve the energy efficiency by 6.2% at the current density of 50 mA cm-2. This method is expected to realize low cost, green and renewable porous carbon materials for future energy storage systems.

In Situ Construction of CNT/CuS Hybrids and Their Application in Photodegradation for Removing Organic Dyes.

Herein, a coprecipitation method used to synthesize CuS nanostructures is reported. By varying the reaction time and temperature, the evolution of the CuS morphology between nanoparticles and nanoflakes was investigated. It was found that CuS easily crystallizes into sphere-/ellipsoid-like nanoparticles within a short reaction time (0.5 h) or at a high reaction temperature (120 °C), whereas CuS nanoflakes are readily formed at a low reaction temperature (20 °C) for a long time (12 h). Photodegradation experiments demonstrate that CuS nanoflakes exhibit a higher photodegradation performance than CuS nanoparticles for removing rhodamine B (RhB) from aqueous solution under simulated sunlight irradiation. Carbon nanotubes (CNTs) were further used to modify the photodegradation performance of a CuS photocatalyst. To achieve this aim, CNTs and CuS were integrated to form CNT/CuS hybrid composites via an in situ coprecipitation method. In the in situ constructed CNT/CuS composites, CuS is preferably formed as nanoparticles, but cannot be crystallized into nanoflakes. Compared to bare CuS, the CNT/CuS composites manifest an obviously enhanced photodegradation of RhB; notably, the 3% CNT/CuS composite with CNT content of 3% showed the highest photodegradation performance (η = 89.4% for 120 min reaction, kapp = 0.01782 min-1). To make a comparison, CuS nanoflakes and CNTs were mechanically mixed in absolute alcohol and then dried to obtain the 3% CNT/CuS-MD composite. It was observed that the 3% CNT/CuS-MD composite exhibited a slightly higher photodegradation performance (η = 92.4%, kapp = 0.0208 min-1) than the 3% CNT/CuS composite, which may be attributed to the fact that CuS maintains the morphology of nanoflakes in the 3% CNT/CuS-MD composite. The underlying enhanced photocatalytic mechanism of the CNT/CuS composites was systematically investigated and discussed.

Temperature-Invariant Superelastic and Fatigue Resistant Carbon Nanofiber Aerogels.

Superelastic and fatigue-resistant materials that can work over a wide temperature range are highly desired for diverse applications. A morphology-retained and scalable carbonization method is reported to thermally convert a structural biological material (i.e., bacterial cellulose) into graphitic carbon nanofiber aerogel by engineering the pyrolysis chemistry. The prepared carbon aerogel perfectly inherits the hierarchical structures of bacterial cellulose from macroscopic to microscopic scales, resulting in remarkable thermomechanical properties. In particular, it maintains superelasticity without plastic deformation even after 2 × 106 compressive cycles and exhibits exceptional temperature-invariant superelasticity and fatigue resistance over a wide temperature range at least from -100 to 500 °C. This aerogel shows unique advantages over polymeric foams, metallic foams, and ceramic foams in terms of thermomechanical stability and fatigue resistance, with the realization of scalable synthesis and the economic advantage of biological materials.

Fabrication of core@shell structural Fe-Fe2O3@PHCP nanochains with high saturation magnetization and abundant amino groups for hexavalent chromium adsorption and reduction.

The rational design of novel adsorption materials is imperative to remove toxic metal species from the polluted water. Herein, a core@shell structural Fe-Fe2O3@poly (hexachlorocyclotriphosphazene-co-polyethylenimine) (Fe-Fe2O3@PHCP) magnetic nanochain with high saturation magnetization was fabricated and used for effective adsorption and reduction of hexavalent chromium. The morphology and microstructure of Fe-Fe2O3@PHCP were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The effects of concentration, pH, contact time, temperature and coexisting ions on Cr (VI) removal were studied. Four kinetic models (pseudo-first-order, pseudo-second-order, Bangham and intraparticle diffusion models) and two isotherm models (Freundlich and Langmuir) were used to fit experimental data. Results show the adsorption capacity of Fe-Fe2O3@PHCP for Cr (VI) is up to 229.0 mg g-1. The excellent performance was ascribed to the favorable reduction of Cr (VI) to Cr (III), followed by the chelation of Cr (III) with imino groups. Meanwhile, the residual Cr (VI) were adsorbed on protonated amino and imino groups. The adsorption process is exothermic and spontaneous and nicely follows pseudo-second-order kinetics, intraparticle diffusion model and Langmuir isotherm model. These results indicated that easily separable Fe-Fe2O3@PHCP magnetic nanochains could be a promising adsorbent to remediate chromate wastewater.

Magnetic hollow poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol)-Fe3O4 hybrid nanocapsules for adsorbing Safranine T and catalytic oxidation of 3,3',5,5'-tetramethylbenzidine.

The development of novel adsorbents with high adsorption capacity and easy recovery property is imperative in the field of wastewater treatment. In this study, a hard template-induced assembly strategy was developed to fabricate the magnetic hollow poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol)-Fe3O4 (PZS-Fe3O4) hybrid nanocapsules, in which Fe3O4 nanoparticles were well embedded in the cross-linked PZS shell. The resulting samples were well characterized using SEM, TEM, EDS, FT-IR, VSM, XPS, XRD and N2 sorption. Then, using Safranine T (ST) as model dye, the adsorption behavior of as-prepared hollow PZS-Fe3O4 nanocapsules including adsorption kinetics, adsorption isotherms, adsorption mechanism, and recyclability were systematically evaluated and discussed. The results revealed that the magnetic hollow PZS-Fe3O4 nanocapsules own high adsorption capacity towards ST dye and outstanding magnetic separation functionality. The pseudo-second-order kinetic model and the Langmuir model can well describe the experimental data, and the adsorption process is controlled by more than one diffusion step. The interaction between ST dye and hollow PZS-Fe3O4 nanocapsules is ascribed to π-π interaction and electrostatic interaction. The thermodynamic parameters demonstrated that the adsorption processes were physical, endothermic, and spontaneous. Additionally, the magnetic hollow PZS-Fe3O4 nanocapsules also shows excellent peroxidase-like catalytic activity in the oxidation of 3,3',5,5'-tetramethylbenzidine with H2O2, indirectly confirming the adsorption kinetic results.

Large-scale fabrication of N-doped porous carbon nanosheets for dye adsorption and supercapacitor applications.

The development of novel large-scale synthesis protocols for heteroatom-doped porous carbon nanosheets is highly imperative for wastewater purification and high-performance electrode materials. In the present work, we propose a simple and feasible explosion-assisted activation strategy to fabricate a kind of N-doped porous carbon nanosheet (N-PCNS) at a large scale, in which only lactose and zinc nitrate were used as raw materials. The obtained N-PCNS possesses hierarchical micro- and mesopore nanostructures with a high specific surface area of 879 m2 g-1 while keeping a high nitrogen content of 3.73 at%. The adsorption properties of the N-PCNS were systematically evaluated through adsorption of neutral red (NR) dye. The adsorption capacity of the N-PCNS was as high as 439.6 mg g-1, meanwhile the adsorption process exhibited fine correlation with the Langmuir isotherm and pseudo-second-order kinetic models. As an electrode material for supercapacitors, the specific capacitance of the N-PCNS is up to 263 F g-1 at 1 A g-1 and 194 F g-1 at 20 A g-1, revealing superior rate performance. The capacitance retention after 10 000 cycles at 20 A g-1 is 96%, demonstrating excellent cycling stability. Our work provides an effective approach to achieve the large-scale preparation of high-performance doped carbon materials.

Transposable elements drive rapid phenotypic variation in Capsella rubella.

Rapid phenotypic changes in traits of adaptive significance are crucial for organisms to thrive in changing environments. How such phenotypic variation is achieved rapidly, despite limited genetic variation in species that experience a genetic bottleneck is unknown. Capsella rubella, an annual and inbreeding forb (Brassicaceae), is a great system for studying this basic question. Its distribution is wider than those of its congeneric species, despite an extreme genetic bottleneck event that severely diminished its genetic variation. Here, we demonstrate that transposable elements (TEs) are an important source of genetic variation that could account for its high phenotypic diversity. TEs are (i) highly enriched in C. rubella compared with its outcrossing sister species Capsella grandiflora, and (ii) 4.2% of polymorphic TEs in C. rubella are associated with variation in the expression levels of their adjacent genes. Furthermore, we show that frequent TE insertions at FLOWERING LOCUS C (FLC) in natural populations of C. rubella could explain 12.5% of the natural variation in flowering time, a key life history trait correlated with fitness and adaptation. In particular, we show that a recent TE insertion at the 3' UTR of FLC affects mRNA stability, which results in reducing its steady-state expression levels, to promote the onset of flowering. Our results highlight that TE insertions can drive rapid phenotypic variation, which could potentially help with adaptation to changing environments in a species with limited standing genetic variation.

Adaptation and Phenotypic Diversification in Arabidopsis through Loss-of-Function Mutations in Protein-Coding Genes.

According to the less-is-more hypothesis, gene loss is an engine for evolutionary change. Loss-of-function (LoF) mutations resulting in the natural knockout of protein-coding genes not only provide information about gene function but also play important roles in adaptation and phenotypic diversification. Although the less-is-more hypothesis was proposed two decades ago, it remains to be explored on a large scale. In this study, we identified 60,819 LoF variants in 1071 Arabidopsis (Arabidopsis thaliana) genomes and found that 34% of Arabidopsis protein-coding genes annotated in the Columbia-0 genome do not have any LoF variants. We found that nucleotide diversity, transposable element density, and gene family size are strongly correlated with the presence of LoF variants. Intriguingly, 0.9% of LoF variants with minor allele frequency larger than 0.5% are associated with climate change. In addition, in the Yangtze River basin population, 1% of genes with LoF mutations were under positive selection, providing important insights into the contribution of LoF mutations to adaptation. In particular, our results demonstrate that LoF mutations shape diverse phenotypic traits. Overall, our results highlight the importance of the LoF variants for the adaptation and phenotypic diversification of plants.

Three-Phase Partitioning for the Extraction and Purification of Polysaccharides from the Immunomodulatory Medicinal Mushroom Inonotus obliquus.

Polysaccharides from the immunomodulatory medicinal mushroom Inonotus obliquus (IOPS) were extracted and purified using three-phase partitioning (TPP), which is an efficient, fast, safe, and green purification technique. An optimal extraction procedure that gave a good 2.2% isolated yield was identified, using the following protocol: a solid-liquid ratio of 1 g to 12 mL; mass fraction of (NH4)2SO4 20% (w/v); 11 mL t-butanol; pH 8.0; temperature 30 °C; and extraction time 30 min. The purified IOPS was shown to be a proteoglycan of 40 kDa molecular weight comprising of d-galactose, d-glucose, d-xylose, and d-mannose in a molar ratio of 2.0:3.5:1.0:1.5. The purified IOPS displayed strong free-radical scavenging abilities, antioxidant activities, and immunological activity in vitro. IOPS' Trolox antioxidant equivalent capacity and ferric-reducing ability of plasma were 251.2 µmol Trolox/g sample and 1040.5 µmol Fe2+/g sample, respectively, with the activity of its immunomodulatory behavior shown to be gradient dependent.

Transposable Elements Contribute to the Adaptation of Arabidopsis thaliana.

Transposable elements (TEs) are mobile genetic elements with very high mutation rates that play important roles in shaping genome architecture and regulating phenotypic variation. However, the extent to which TEs influence the adaptation of organisms in their natural habitats is largely unknown. Here, we scanned 201 representative resequenced genomes from the model plant Arabidopsis thaliana and identified 2,311 polymorphic TEs from noncentromeric regions. We found expansion and contraction of different types of TEs in different A. thaliana populations. More importantly, we identified two TE insertions that are likely candidates to play a role in adaptive evolution. Our results highlight the importance of variations in TEs for the adaptation of plants in general in the context of rapid global climate change.

Electron Transfer and Geometric Conversion of Co-NO Moiety in Saddled Porphyrins: Implications for Trigger Role of Tetrapyrrole Distortion.

The electrons of NO and Co are strongly delocalized in normal {Co-NO}8 species. In this work, {Co-NO}8 complexes are induced to convert from (CoII)+•-NO• to CoIII-NO- by a core contraction of 0.06 Šin saddled cobalt(II) porphyrins. This intramolecular electron transfer mechanism indicates that nonplanarity of porphyrin is involved in driving conversion of the NO units from electrophilic NO• as a bent geometry to nucleophilic NO- as a linear geometry. This implies that distortion acts as a trigger in enzymes containing tetrapyrrole. The electronic behaviors of the CoII ions and Co-NO moieties were confirmed by X-ray crystallography, EPR spectroscopy, theoretical calculation, UV-vis and IR spectroscopy, and electrochemistry.