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With strong spin–orbit coupling (SOC), ultrathin two-dimensional (2D) transitional metal chalcogenides (TMDs) are predicted to exhibit weak antilocalization (WAL) effect at low temperatures. The observation of WAL effect in VSe2is challenging due to the relative weak SOC and three-dimensional (3D) transport nature in thick VSe2. Here, we report on the observation of quasi-2D transport and WAL effect in sublimed-salt-assisted low-temperature chemical vapor deposition (CVD) grown few-layered high-quality VSe2nanosheets. The WAL magnitudes in magnetoconductance can be perfectly fitted by the 2D Hikami–Larkin–Nagaoka (HLN) equation in the presence of strong SOC, by which the spin–orbit scattering length lSOand phase coherence length lϕhave been extracted. The phase coherence length lϕshows a power law dependence with temperature, lϕ∼ T–1/2, revealing an electron–electron interaction-dominated dephasing mechanism. Such sublimed-salt-assisted growth of high-quality few-layered VSe2and the observation of WAL pave the way for future spintronic and valleytronic applications.

Controlling the spin angular momentum of light (or circular polarization state) plays a crucial role in the modern photonic applications such as optical communication, circular dichroism spectroscopy, and quantum information processing. However, the conventional approaches to manipulate the spin of light require naturally occurring chiral or birefringent materials of bulky sizes due to the weak light–matter interactions. Here we experimentally demonstrate an approach to implement spin-selective transmission in the infrared region based on chiral folded metasurfaces that are capable of transmitting one spin state of light while largely prohibiting the other. Due to the intrinsic chirality of the folded metasurface, a remarkable circular dichroism as large as 0.7 with the maximum transmittance exceeding 92% is experimentally demonstrated. The giant circular dichroism is interpreted within the framework of charge-current multipole expansion. Moreover, the intrinsic chirality can be readily controlled by manipulating the folding angle of the metasurface with respect to the cardinal plane. Benefiting from its strong chirality and spin-dependent transmission characteristics, the proposed folded metasurface may be applied to a range of novel photon-spin selective devices for optical communication technologies and biophotonics.

Background: Insulin resistance (IR) had been reported to be associated with age; however, few studies have explored the association between IR and biological age (BA). The HOMA-IR value is a useful indicator of the extent of IR. This cross-sectional study is to explore the relationship between HOMA-IR and BA/advanced aging in the US population. Methods: This study is a cross-sectional analysis of National Health and Nutrition Examination Survey (NHANES) data. The survey comprised 12,266 people from the NHANES, and their full HOMA-IR data as well as BA data were extracted. Four multiple linear regressions were performed to analyze the association between HOMA-IR and BA, and four multiple logistic regression models were performed to analyze the association between HOMA-IR and advanced aging. In addition, trend tests and stratified analysis were performed and smoothed fitted curves were plotted to test the robustness of the results. Results: HOMA-IR was positively correlated with BA [β: 0.51 (0.39, 0.63)], and it was the same to advanced aging [OR: 1.05 (1.02, 1.07)], and both showed a monotonically increasing trend. The trend tests showed that the results were stable (all Pfor trend < 0.0001). The smoothed fitted curves showed that there were non-linear relationships between HOMA-IR and BA/advanced aging. And the stratified analysis indicated that the relationship between HOMA-IR and BA/advanced aging remained robust in all subgroups. Conclusion: The study suggested that HOMA-IR is positively correlated with BA and advanced aging in the US adult population, with a monotonic upward trend. This is a new finding to reveal the relationship between HOMA-IR and age from new standpoint of BA rather than chronological age (CA). And it may contribute to a better understanding of human health aging and may aid future research in this field.

Litchi is one of the most important subtropical evergreen fruit trees in southern Asia. Previous studies indicated that high-temperature conditions encourage growth of rudimentary leaves in panicles and suppress flowering. We have demonstrated that methyl viologen dichloride hydrate (MV) and sodium nitroprusside (SNP) promoted flowering in litchi partially by inhibiting the growth of rudimentary leaves via reactive oxygen species (ROS) and nitric oxide (NO). In the present study, we examined the microstructure and ultrastructure, programmed cell death (PCD) ratio, nuclei morphology of the rudimentary leaves, and the expression of senescence-related genes after the treatment with ROS or NO. The results showed that chromatins of the ROS- or NO-treated cells in the rudimentary leaves were condensed. Fusion of the cytoplasm-digesting vesicles with the vacuole and degradation of cytoplasm forming scattered debris were found in those of the treated cells. Treatment with ROS or NO increased the cell PCD ratio. Morphology of the nuclei stained by propidium iodide (PI) showed that nuclei shape became irregular after the ROS or NO treatment. Further, the expression levels of LcRboh, LcMC-1-like, and LcPirinwere higher in the ROS- and NO-treated rudimentary leaves than those in the control ones, suggesting that these genes may be involved in the ROS and NO-induced senescence and abscission of the rudimentary leaves in litchi. Our results suggested that ROS and NO play an important role in inducing the senescence of the rudimentary leaves, and ROS- and NO-induced PCD may be involved in the regulation of the rudimentary leaf growth in litchi. Warmer winter temperatures suppress flowering of litchi trees, threatening fruit production, but researchers have found another way to trigger litchi trees to reproduce. In litchi, spring buds contain both flower and leaf primordia, and cold cues the plants to shed the young leaves, allowing the flower primordia to develop. With recent warmer winters, the leaves are crowding out the flowers. Biyan Zhou at South China Agricultural University investigated whether spraying with compounds that make the trees produce stress-signaling molecules, such as nitrous oxide, would mimic the effects of a cold winter. Following treatment, the trees shed their rudimentary leaves and flowers developed. Microscopic examination of buds showed that the leaf shedding process looked similar to cold-triggered shedding. This study offers a method to induce litchis to flower and fruit, even in a changing climate.

Fe2O3nanorods and hexagonal nanoplates were synthesized and used as the promoters for Pt electrocatalysts toward the methanol oxidation reaction (MOR) in an alkaline electrolyte. The catalysts were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammetry and chronoamperometry. The results show that the presence of Fe2O3in the electrocatalysts can promote the kinetic processes of MOR on Pt, and this promoting effect is related to the morphology of the Fe2O3promoter. The catalyst with Fe2O3nanorods as the promoter (Pt-Fe2O3/C-R) exhibits much higher catalytic activity and stability than that with Fe2O3nanoplates as the promoter (Pt-Fe2O3/C-P). The mass activity and specific activity of Pt in a Pt-Fe2O3/C-R catalyst are 5.32 A/mgPtand 162.7 A/m2Pt, respectively, which are approximately 1.67 and 2.04 times those of the Pt-Fe2O3/C-P catalyst, and 4.19 and 6.16 times those of a commercial PtRu/C catalyst, respectively. Synergistic effects between Fe2O3and Pt and the high content of Pt oxides in the catalysts are responsible for the improvement. These findings contribute not only to our understanding of the MOR mechanism but also to the development of advanced electrocatalysts with high catalytic properties for direct methanol fuel cells.

The performances of GaN-based vertical light emitting diodes with surface texture of GaN cones were studied. The cones were fabricated by inductively coupled plasma reactive ion etching with Cr mask, which can enhance the light intensity by about 95 % at injection current of 350 mA. Angle and wavelength-resolved far-field spectra were measured, and the maximum light enhancement lies at about ±15°–50° respect to normal direction. This is because of the successive reflection of light by the sidewall of cones, which can be concluded from the far-field pattern that the Fabry-Perot like resonance of patterned LED disappears compared to the original device. The polarization property of patterned LED was also analyzed, which can explain the increasing of enhancement ratio with injection current.

Pd-based nanomaterials have been considered as an effective catalyst for formic acid electrooxidation reaction (FAOR). Herein, we reported two types of polyaniline (PANI)-promoted Pd catalysts. One was an nPANI/Pd electrocatalyst prepared by the electropolymerization of aniline and the electrodeposition of Pd. The other was a Pd/C/nPANI catalyst prepared by the direct electropolymerization of aniline on a commercial Pd/C catalyst. The results show that PANI alone has no catalytic activity for FAOR; however, PANI can exhibit a significant promoting effect to Pd. The current densities of FAOR on the Pd catalysts with a PANI coating show a significant increase compared with that of the Pd reference catalyst without PANI as a promoter. The promoting effects of PANI are strongly dependent on the electropolymerization potential cycles (n). The highest catalytic activities for FAOR of all the nPANI/Pd and Pd/C/nPANI catalysts were those of 15PANI/Pd and Pd/C/20PANI. The mass-specific activity (MSA) of Pd in 15PANI/Pd was 7.5 times that of the Pd catalyst, and the MSA and intrinsic activity of Pd/C/20PANI were 2.3 and 3.3 times that of the Pd/C catalyst, respectively. The enhanced performance of Pd catalysts is proposed as an electronic effect between Pd nanoparticles and PANI.

An ultrathin layer is investigated for its potential application of replacing conventional diffusion barriers and promoting interface adhesion for nanoelectric circuits with porous ultralow dielectrics. The porous ultralow dielectric (k≈ 2.5) substrate is silanized by 3-aminopropyltrimethoxysilane (APTMS) to form the nanoadhesive layer by performing oxygen plasma modification and tailoring the silanization conditions appropriately. The high primary amine content is obtained in favor of strong interaction between amino groups and copper. And the results of leakage current measurements of metal-oxide-semiconductor capacitor structure demonstrate that the aminosilanization nanoadhesive layer can block copper diffusion effectively and guarantee the performance of devices. Furthermore, the results of four-point bending tests indicate that the nanoadhesive layer with monolayer structure can provide the satisfactory interface toughness up to 6.7 ± 0.5 J/m2for Cu/ultralow-kinterface. Additionally, an annealing-enhanced interface toughness effect occurs because of the formation of Cu–N bonding and siloxane bridges below 500 °C. However, the interface is weakened on account of the oxidization of amines and copper as well as the breaking of Cu–N bonding above 500 °C. It is also found that APTMS nanoadhesive layer with multilayer structure provides relatively low interface toughness compared with monolayer structure, which is mainly correlated to the breaking of interlayer hydrogen bonding.

Ferromagnetism in graphite/graphenes is attractive for fundamental science and potential applications in carbon-based magnetism and spintronics. In this work, we show that magnetic particle inspection can be miniaturized to detect local magnetic moments with a high spatial resolution of ∼1.0 nm using scanning electron microscopy. A metal nanowire and adjacent nanogap can be found at the edges of graphenes and graphite for atoms with magnetic moments (Fe, Co, Ni, Mn, Pd, Al), whereas no similar characteristics are found for diamagnetic metals (Au, Ag). By investigating these features under an external magnetic field and at different temperatures, we discuss possible mechanisms and propose that intrinsic ferromagnets exist and form a one-dimensional array at the edges of graphenes and graphite. Meanwhile, the size of individual magnets (<4.8 Å), orientation, magnitude (∼0.45 μBper carbon edge atom) of magnetic moments, and their Curie temperature (>95 °C) are obtained, which are novel and interesting.

By means of the CALPHAD technique, the Er–Pd system was critically assessed. The solution phases (liquid, f.c.c. and h.c.p.) are modeled with the Redlich–Kister equation. The intermetallic compounds ErPd3and ErPd, which have a homogeneity range, are treated as the phases MPd3and ErM, respectively, by a two-sublattice model with Pd in MPd3and Er in ErM on one sublattice and M on the other one, where M is used as an abbreviation for a mixture of Er and Pd. The other compounds were treated as stoichiometric. A set of self-consistent thermodynamic parameters of the Er–Pd system was obtained.

The evidence of Acupuncture combined with speech rehabilitation training for post-stroke dysarthria is insufficient and there is no consensus on its efficacy.