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Precise regulation of the active site structure is an important means to enhance the activity and selectivity of catalysts in CO 2 electroreduction. Here, we creatively introduce anionic groups, which can not only stabilize metal sites with strong coordination ability but also have rich interactions with protons at active sites to modify the electronic structure and proton transfer process of catalysts. This strategy helps to convert CO 2 into fuel chemicals at low overpotentials. As a typical example, a composite catalyst, CuO/Cu-NSO 4 /CN, with highly dispersed Cu(II)-SO 4 sites has been reported, in which CO 2 electroreduction to formate occurs at a low overpotential with a high Faradaic efficiency (-0.5 V vs. RHE, FE formate =87.4 %). Pure HCOOH is produced with an energy conversion efficiency of 44.3 % at a cell voltage of 2.8 V. Theoretical modeling demonstrates that sulfate promotes CO 2 transformation into a carboxyl intermediate followed by HCOOH generation, whose mechanism is significantly different from that of the traditional process via a formate intermediate for HCOOH production., (© 2024 Wiley-VCH GmbH.)

Vertically stacked multiple atomically thin layers have recently widened the landscape of rich optical structures thanks to these quantum metamaterials or van der Waals (vdW) materials, featuring hyperbolic polaritons with unprecedented avenues for light. Despite their far-reaching implications, most of their properties rest entirely on a trivial band topological origin. Here, a 2D approach is adopted toward a micromechanical vdW analogue that, as a result of engineered chiral and mirror symmetries, provides topologically resilient hyperbolic radiation of mechanical vibrations in the ultrasonic regime. By applying laser vibrometry of the micrometer-sized metasurface, we are able to exhibit the exotic fingerprints of robust hyperbolic radiation spanning several frequencies, which beyond their physical relevance, may enable ultrasonic technologies., (© 2024 Wiley‐VCH GmbH.)

Non-Abelian topological phases (NATPs) exhibit enigmatic intrinsic physics distinct from well-established Abelian topological phases, while lacking straightforward configuration and manipulation, especially for classical waves. In this Letter, we exploit novel braiding-type couplings among a pair of triple-component acoustic dipoles, which act as functional elements with effective imaginary couplings. Sequencing them in one dimension allows us to generate acoustic NATPs in a compact yet time-reversal invariant Hermitian system. We further provide the whole phase diagram that encompasses all i, j, and k non-Abelian phases, and directly demonstrate their unique quotient relations via different end point states. Our NATPs based on real-space braiding may inspire the exploration of acoustic devices with non-commutative characters.

Ethnopharmacological Relevance: Fructus Tribuli (FT), a traditional Chinese medicinal herbal, has been used for the clinical treatment of cardiovascular diseases for many years and affects vascular endothelial dysfunction (ED) in patients with hypertension., Aim of the Study: This study aimed to demonstrate the pharmacodynamic basis and mechanisms of FT for the treatment of ED., Materials and Methods: The present study used ultra-high-performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) to analyze and identify the chemical components of FT. The active components in blood were determined after the oral administration of FT by comparative analysis to blank plasma. Then, based on the active components in vivo, network pharmacology was performed to predict the potential targets of FT in treating ED. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were also performed, and component-target-pathway networks were constructed. Interactions between the major active components and main targets were verified by molecular docking. Moreover, spontaneously hypertensive rats (SHRs) were divided into the normal, model, valsartan, low-dose FT, medium-dose FT, and high-dose FT experimental groups. In pharmacodynamic verification studies, treatment effects on blood pressure, serum markers (nitric oxide [NO], endothelin-1 [ET-1,], and angiotensin Ⅱ [Ang Ⅱ)]) of ED, and endothelial morphology of the thoracic aorta were evaluated and compared between groups. Finally, the PI3K/AKT/eNOS pathway was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot of the thoracic aorta of rats in each group to detect the mRNA expression of PI3K, AKT, and eNOS and the protein expression of PI3K, AKT, p-AKT, eNOS, and p-eNOS., Results: A total of 51 chemical components were identified in FT, and 49 active components were identified in rat plasma. Thirteen major active components, 22 main targets, and the PI3K/AKT signaling pathway were screened by network pharmacology. The animal experiment results showed that FT reduced systolic blood pressure and ET-1 and Ang Ⅱ levels and increased NO levels in SHRs to varying degrees. The therapeutic effects were positively correlated with the oral dose of FT. Hematoxylin-eosin (HE) staining confirmed that FT could alleviate the pathological damage of the vascular endothelium. qRT-PCR and Western blot analysis confirmed that up-regulated expression of the PI3K/AKT/eNOS signaling pathway could improve ED., Conclusions: In this study, the material basis of FT was comprehensively identified, and the protective effect on ED was confirmed. FT had a treatment effect on ED through multi-component, multi-target, and multi-pathways. It also played a role by up-regulating the PI3K/AKT/eNOS signaling pathway., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Fermionic time-reversal symmetry ([Formula: see text])-protected quantum spin Hall (QSH) materials feature gapless helical edge states when adjacent to arbitrary trivial cladding materials. However, due to symmetry reduction at the boundary, bosonic counterparts usually exhibit gaps and thus require additional cladding crystals to maintain robustness, limiting their applications. In this study, we demonstrate an ideal acoustic QSH with gapless behaviour by constructing a global T f on both the bulk and the boundary based on bilayer structures. Consequently, a pair of helical edge states robustly winds several times in the first Brillouin zone when coupled to resonators, promising broadband topological slow waves. We further reveal that this ideal QSH phase behaves as a topological phase transition plane that bridges trivial and higher-order phases. Our versatile multi-topology platform sheds light on compact topological slow-wave and lasing devices., (© 2023. The Author(s).)

Three-dimensional topological Dirac semimetal (DSM) is a vital state to explore topological phases and phase transitions. However, its bulk-boundary correspondence is elusive. Here, we experimentally investigate the higher-order hinge states in an acoustic DSM. Not only removable trivial surface states but also robust nontrivial hinge arcs are observed, attributed to the direct correspondence between bulk polarization and hinge charge. We further reveal that a pair of zigzag and bearded hinges possess arcs located in complementary momentum regions. Our work provides solid proof of the bulk-hinge correspondence in DSM and sheds light on the study of topological hierarchy across dimensions.

Stable and efficient guided waves are essential for information transmission and processing. Recently, topological valley-contrasting materials in condensed matter systems have been revealed as promising infrastructures for guiding classical waves, for they can provide broadband, non-dispersive and reflection-free electromagnetic/mechanical wave transport with a high degree of freedom. In this work, by designing and manufacturing miniaturized phononic crystals on a semi-infinite substrate, we experimentally realized a valley-locked edge transport for surface acoustic waves (SAWs). Critically, original one-dimensional edge transports could be extended to quasi-two-dimensional ones by doping SAW Dirac "semimetal" layers at the boundaries. We demonstrate that SAWs in the extended topological valley-locked edges are robust against bending and wavelength-scaled defects. Also, this mechanism is configurable and robust depending on the doping, offering various on-chip acoustic manipulation, e.g., SAW routing, focusing, splitting, and converging, all flexible and high-flow. This work may promote future hybrid phononic circuits for acoustic information processing, sensing, and manipulation., (© 2022. The Author(s).)

As a special bio-geomorphic landscape in the Qaidam desert area, Nitraria tangutorum nebkhas play a critical role in fixing quicksand, improving soil quality, and maintaining the stability of regional ecological environment. Taking the N. tangutorum nebkhas with coverage of approximately 15%, 25%, 45% and 60% in Gahai Lake area of Qaidam Basin as the research objects, we analyzed the vertical distribution and enrichment characteristics of soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the contents of SOM, TN, TP, TK, AN, AP and AK varied in the range of 1.67-10.22 g·kg -1 , 0.05-0.42 g·kg -1 , 0.31-0.54 g·kg -1 , 15.87-18.84 g·kg -1 , 2.26-11.68 mg·kg -1 , 0.80-15.00 mg·kg -1 and 45-161 mg·kg -1 , respectively. Vertically, soil nutrients in the N. tangutorum nebkhas with 15% coverage showed a decreasing trend first then increased, and then decreased again with the increase of soil depth, except for TP, which did not show any significant change. In the nebkhas with 25%, 45% and 60% coverage, SOM, TN, AN, TP and AP all showed a decreasing trend with increasing soil depth ,whereas TK and AK did not change significantly with soil layer. Above the nebkhas ground level of N. tangutorum , SOM, TN, TK, AN, AP and AK were all enriched, especially in the surface layer.Aamong all the nutrients, the enrichment rate of AN reached 5.19. In addition, below the nebkhas ground level of N. tangutorum , TN, AN, TK, AK and AP also showed enrichment. SOM, TN, AN, TP, AP, TK and AK were all significantly positively correlated with soil water content, and negatively correlated with altitude. All nutrients except TP were mainly affected by altitude. In conclusion, soil nutrient content of N. tangutorum nebkhas was the highest in the surface layer, the enrichment effect of which was not only reflected in the interior of the nebkhas, but also below the ground level of the nebkhas. Our results could provide reference for the scientific utilization of N. tangutorum nebkhas and ecological environment protection in Qaidam Basin area.

Coronavirus Disease 2019 (COVID-19) infected by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been declared a public health emergency of international concerns. Cytokine storm syndrome (CSS) is a critical clinical symptom of severe COVID-19 patients, and the macrophage is recognized as the direct host cell of SARS-CoV-2 and potential drivers of CSS. In the present study, peramivir was identified to reduce TNF-α by partly intervention of NF-κB activity in LPS-induced macrophage model. In vivo , peramivir reduced the multi-cytokines in serum and bronchoalveolar lavage fluid (BALF), alleviated the acute lung injury and prolonged the survival time in mice. In human peripheral blood mononuclear cells (hPBMCs), peramivir could also inhibit the release of TNF-α. Collectively, we proposed that peramivir might be a candidate for the treatment of COVID-19 and other infections related CSS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhang, Tu, Sun, Chen, Zhang, Zhuang, Wang and Su.)

Ethnopharmacological Relevance: Fructus Tribuli (FT) has been commonly used as a traditional medicine for thousands of years. With the diverse uses of FT, more attention has been paid to its hepatorenal toxicity. However, the compounds causing the hepatorenal toxicity of FT remain undetermined. Terrestrosin D (TED), a major spirostanol saponin isolated from FT, may exert hepatorenal toxicity., Aim of the Study: This study aimed to evaluate the potential hepatorenal toxicity of TED, and preliminarily explore the possible mechanism of TED-induced hepatorenal toxicity., Materials and Methods: Cytotoxicity assays, a repeated-dose 28-day in-vivo study, a toxicokinetic study, and a tissue distribution study were used to evaluate the potential hepatorenal toxicity of TED. Furthermore, network pharmacology was applied to preliminarily explore the possible mechanism of TED-induced hepatorenal toxicity., Results: Both the in vitro and in vivo studies showed that the spirostanol saponin TED had potential hepatorenal toxicity. Nonetheless, hepatorenal toxicity induced by oral treatment with TED at a dosage range of 5 - 15 mg/kg daily for 28 consecutive days to Sprague-Dawley (SD) rats was reversible after 14 days of TED withdrawal. The toxicokinetic study demonstrated that the systematic exposure of SD rats to TED had an accumulation phenomenon and a dose-dependent trend after a 28-day repeated-dose oral administration. The tissue distribution study revealed that TED had a targeted distribution in the liver and kidneys accompanied by a phenomenon of accumulation in SD rats. Network pharmacology combined with molecular docking methods was used to screen for the key targets (HSP90AA1, CNR1, and DRD2) and the key pathways of TED-induced hepatorenal toxicity., Conclusions: The spirostanol saponin TED, a major spirostanol saponin isolated from FT, had potential hepatorenal toxicity., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Tandem catalysis, in which a CO 2 -to-C 2 process is divided into a CO 2 -to-CO/*CO step and a CO/*CO-to-C 2 step, is promising for enhancing the C 2 product selectivity when using Cu-based electrochemical CO 2 reduction catalysts. In this work, a nanoporous hollow Au/CuO-CuO tandem catalyst was used for catalyzing the eCO 2 RR, which exhibited a C 2 product FE of 52.8% at -1.0 V vs. RHE and a C 2 product partial current density of 78.77 mA cm -2 at -1.5 V vs. RHE. In addition, the C 2 product FE stably remained at over 40% over a wide potential range, from -1.0 V to -1.5 V. This superior performance was attributed to good matching in terms of the optimal working potential and charge-transfer resistance between CO/*CO-production sites (Au/CuO) and CO/*CO-reduction sites (CuO). This site pair matching effect ensured sufficient supplies of CO/*CO and electrons at CuO sites at the working potentials, thus dramatically enhancing the formation rate of C 2 products., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Waveguides and resonators are core components in the large-scale integration of electronics, photonics and phononics, both in existing and future scenarios. In certain situations, there is critical coupling of the two components; i.e. no energy passes through the waveguide after the incoming wave couples into the resonator. The transmission spectral characteristics resulting from this phenomenon are highly advantageous for signal filtering, switching, multiplexing and sensing. In the present study, adopting an elastic-wave platform, we introduce topological insulator (TI), a remarkable achievement in condensed matter physics over the past decade, into a classical waveguide-ring-resonator configuration. Along with basic similarities with classical systems, a TI system has important differences and advantages, mostly owing to the spin-momentum locked transmission states at the TI boundaries. As an example, a two-port TI waveguide resonator can fundamentally eliminate upstream reflections while completely retaining useful transmission spectral characteristics, and maximize the energy in the resonator, with possible applications being novel signal processing, gyro/sensing, lasering, energy harvesting and intense wave-matter interactions, using phonons, photons or even electrons. The present work further enhances confidence in using topological protection for practical device performance and functionalities, especially considering the crucial advantage of introducing (pseudo)spins to existing conventional configurations. More in-depth research on advancing phononics/photonics, especially on-chip, is foreseen., (© The Author(s) 2020. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.)

The original version of this Article contained errors in the second sentence in the legend of Fig. 1, which incorrectly read 'These two elastic insulators are identical in lattice constant a (3a 0 ), plate thickness (0.4a 0 ), and radius of perforated holes r (0.18a 0 ) but different hole-center distance characterized by b.' The correct version states 'plate thickness (√3 × 0.4a 0 )' in place of 'plate thickness (0.4a 0 )' and 'radius of perforated holes r (√3 × 0.18a 0 )' rather than 'radius of perforated holes r (0.18a 0 )'.The first sentence of the 'Sample preparation' section of the Methods originally incorrectly read 'Our samples are prepared exclusively on polished stainless-steel plates (Type 201, mass density 7803 kg m -3 ) with a fixed plate thickness 7.82 mm.' In the corrected version, 'mass density 7903 kg m -3 ' replaces 'mass density 7803 kg m -3 '.The second sentence in the legend of Supplementary Fig. 3, originally incorrectly read 'The symmetry of the phononic crystal remains unchanged as C 6ν , and thickness of the substrates H (equals to 0.4a 0 ), lattice constant a (equals to 3a 0 ) and radius of perforated holes r (equals to 0.18 a 0 ) maintain constant.' The correct version states '√3 × 0.4a 0 ' in place of '0.4a 0 ' and '√3 × 0.18a 0 ' rather than '0.18a 0 '.This has been corrected in both the PDF and HTML versions of the Article.

Topological valley states at the domain wall between two artificial crystals with opposite valley Chern numbers offer a feasible way to realize robust wave transport since only broken spatial symmetry is required. In addition to the valley, spin and crystal dimension are two other important degrees of freedom, particularly in realizing spin-related topological phenomena. Here we experimentally demonstrate that it is possible to construct two-dimensional acoustic topological pseudospin-valley coupled saddle surface states, designed from glide symmetry in a three-dimensional system. By taking advantage of such two-dimensional surface states, a full set of acoustic pseudospins can be realized, exhibiting pseudospin-valley dependent transport. Furthermore, due to the hyperbolic character of the dispersion of saddle surface states, multi-directional anisotropic controllable robust sound transport with little backscattering is observed. Our findings may open research frontiers for acoustic pseudospins and provide a satisfactory platform for exploring unique acoustic topological properties in three-dimensional structures.

Two-dimensional (2D) coupled resonant optical waveguide (CROW), exhibiting topological edge states, provides an efficient platform for designing integrated topological photonic devices. In this paper, we propose an experimentally feasible design of 2D honeycomb CROW photonic structure. The characteristic optical system possesses two-fold and three-fold Dirac points at different positions in the Brillouin zone. The effective gauge fields implemented by the intrinsic pseudo-spin-orbit interaction open up topologically nontrivial bandgaps through the Dirac points. Spatial lattice geometries allow destructive wave interference, leading to a dispersionless, near-flat energy band in the vicinity of the three-fold Dirac point in the telecommunication frequency regime. This nontrivial structure with a near-flat band yields topologically protected edge states. These characteristics underpin the fundamental importance as well as the potential applications in various optical devices. Based on the honeycomb CROW lattice, we design the shape-independent topological cavity and the beam splitter, which demonstrate the relevance for a wide range of photonic applications.

Precise control of solid-state elastic waves' mode content and coherence is of great use nowadays in reinforcing mechanical energy harvesting/storage, nondestructive material testing, wave-matter interaction, high sensitivity sensing, and information processing, etc. Its efficacy is highly dependent on having elastic transmission channels with lower loss and higher degree of freedom. Here, we demonstrate experimentally an elastic analog of the quantum spin Hall effects in a monolithically scalable configuration, which opens up a route in manipulating elastic waves represented by elastic pseudospins with spin-momentum locking. Their unique features including robustness and negligible propagation loss may enhance elastic planar-integrated circuit-level and system-level performance. Our approach promotes topological materials that can interact with solid-state phonons in both static and time-dependent regimes. It thus can be immediately applied to multifarious chip-scale topological phononic devices, such as path-arbitrary elastic wave-guiding, elastic splitters and elastic resonators with high-quality factors.

Objective: To investigate the effect of vitamin D deficiency on susceptibility to spinal tuberculosis and its pathological development., Methods: A case-control design was used in this study. A total of 163 treatment-naïve patients with spinal tuberculosis admitted to this institute for an operation from June 2013 to May 2016 were included in the case group, and 170 subjects who received a health examination in the same hospital were included in the control group. Control group patients were frequency-matched with the case group by age, gender, and season. Serum 25-hydroxyvitamin D levels were detected using an enzyme linked immunosorbent assay (ELISA). Pathological classification of patients in the case group was conducted according to intraoperative findings, and definite diagnosis of spinal tuberculosis was confirmed after operation., Results: The serum level of vitamin D [23.99 (20.55, 29.54) nmol/L] in the case group was lower than that in the control group [42.94 (35.68, 51.04) nmol/L], and the difference was statistically significant (Z = -9.048, P < 0.05). Out of the 163 patients with spinal tuberculosis who underwent pathological classification, 107 cases of caseous necrosis and 56 cases of hyperplasia were identified. Based on the vitamin D levels of the patients in the case group, these patients were further divided into a low-level group (<25 nmol/L) and a high-level group (≥25 nmol/L). The proportion of patients with caseous necrosis in the low-level group (79.17%) was higher than that in the high-level group (46.27%), with a statistically significant difference (χ 2  = 18.937, P < 0.05)., Conclusion: Vitamin D deficiency is associated with susceptibility to spinal tuberculosis and its pathological classification, and vitamin D deficiency affects the occurrence and development of spinal tuberculosis., (Copyright © 2017 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.)

Di-(2-ethylhexyl)-phthalate (DEHP) is causing serious health hazard in wildlife animal and human through environment and food chain, including the effect of brain development and impacted neurobehavioral outcomes. However, DEHP exposure caused cerebellar toxicity in bird remains unclear. To evaluate DEHP-exerted potential neurotoxicity in cerebellum, male quails were exposed with 0, 250, 500 and 750 mg/kg BW/day DEHP by gavage treatment for 45 days. Neurobehavioral abnormality and cerebellar histopathological alternation were observed in DEHP-induced quails. DEHP exposure increased the contents of total Cytochrome P450s (CYPs) and Cytochrome b5 (Cyt b5) and the activities of NADPH-cytochrome c reductase (NCR) and aniline-4-hydeoxylase (AH) in quail cerebellum. The expression of nuclear xenobiotic receptors (NXRs) and the transcriptions of CYP enzyme isoforms were also influenced in cerebellum by DEHP exposure. These results suggested that DEHP exposure caused the toxic effects of quail cerebellum. DEHP exposure disrupted the cerebellar CYP enzyme system homeostasis via affecting the transcription of CYP enzyme isoforms. The cerebellar P450arom and CYP3A4 might be biomarkers in evaluating the neurotoxicity of DEHP in bird. Finally, this study provided new evidence that DEHP-induced toxic effect of quail cerebellum was associated with activating the NXRs responses and disrupting the CYP enzyme system homeostasis., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Selenophosphate synthetase (SPS) is essential for selenoprotein biosynthesis. In two SPS paralogues, SPS1 was only cloned from a cDNA library prepared from avian organ. However, the biological function of SPS1 in chicken central nervous system (CNS) remains largely unclear. To investigate the role of avian SPS1 in the development and selenium (Se) homeostasis of CNS, fertile eggs, chicken embryos, embryo neurons and chicks were employed in this study. The response of SPS1 transcription to the development and Se levels of CNS tissues was analyzed using qRT-PCR. SPS1 gene exists extensively in the development of chicken CNS. The wide expression of avian SPS1 can be controlled by the Se content levels, which suggests that SPS1 is important in the regulation of Se homeostasis. The fundamental mechanism of these effects is that Se alters the half-life and stability of SPS1 mRNA. Therefore, SPS1 exerts an irreplaceable biological function in chicken CNS and Se homeostasis is closely related to the expression of SPS1. These results suggested that SPS1 was required for the development and Se homeostasis of CNS in chicken.

Knowledge about mammalian selenoproteins is increasing. However, the selenoproteome of birds remains considerably less understood, especially concerning its biochemical characterization, structure-function relationships and the interactions of binding molecules. In this work, the SECIS elements, subcellular localization, protein domains and interactions of binding molecules of the selenoproteome in Gallus gallus were analyzed using bioinformatics tools. We carried out comprehensive analyses of the structure-function relationships and interactions of the binding molecules of selenoproteins, to provide biochemical characterization of the selenoproteome in Gallus gallus. Our data provided a wealth of information on the biochemical functions of bird selenoproteins. Members of the selenoproteome were found to be involved in various biological processes in chickens, such as in antioxidants, maintenance of the redox balance, Se transport, and interactions with metals. Six membrane-bound selenoproteins (SelI, SelK, SelS, SelT, DIO1 and DIO3) played important roles in maintaining the membrane integrity. Chicken selenoproteins were classified according to their ligand binding sites as zinc-containing matrix metalloselenoproteins (Sep15, MsrB1, SelW and SelM), POP-containing selenoproteins (GPx1-4), FAD-interacting selenoproteins (TrxR1-3), secretory transport selenoproteins (GPx3 and SelPa) and other selenoproteins. The results of our study provided new evidence for the unknown biological functions of the selenoproteome in birds. Future research is required to confirm the novel biochemical functions of bird selenoproteins.

Strategic manipulation of wave and particle transport in various media is the key driving force for modern information processing and communication. In a strongly scattering medium, waves and particles exhibit versatile transport characteristics such as localization, tunnelling with exponential decay, ballistic, and diffusion behaviours due to dynamical multiple scattering from strong scatters or impurities. Recent investigations of graphene have offered a unique approach, from a quantum point of view, to design the dispersion of electrons on demand, enabling relativistic massless Dirac quasiparticles, and thus inducing low-loss transport either ballistically or diffusively. Here, we report an experimental demonstration of an artificial phononic graphene tailored for surface phonons on a LiNbO 3 integrated platform. The system exhibits Dirac quasiparticle-like transport, that is, pseudo-diffusion at the Dirac point, which gives rise to a thickness-independent temporal beating for transmitted pulses, an analogue of Zitterbewegung effects. The demonstrated fully integrated artificial phononic graphene platform here constitutes a step towards on-chip quantum simulators of graphene and unique monolithic electro-acoustic integrated circuits.

A topological insulator is a material with an insulating interior but time-reversal symmetry-protected conducting edge states. Since its prediction and discovery almost a decade ago, such a symmetry-protected topological phase has been explored beyond electronic systems in the realm of photonics. Electrons are spin-1/2 particles, whereas photons are spin-1 particles. The distinct spin difference between these two kinds of particles means that their corresponding symmetry is fundamentally different. It is well understood that an electronic topological insulator is protected by the electron's spin-1/2 (fermionic) time-reversal symmetry [Formula: see text] However, the same protection does not exist under normal circumstances for a photonic topological insulator, due to photon's spin-1 (bosonic) time-reversal symmetry [Formula: see text] In this work, we report a design of photonic topological insulator using the Tellegen magnetoelectric coupling as the photonic pseudospin orbit interaction for left and right circularly polarized helical spin states. The Tellegen magnetoelectric coupling breaks bosonic time-reversal symmetry but instead gives rise to a conserved artificial fermionic-like-pseudo time-reversal symmetry, Tp ([Formula: see text]), due to the electromagnetic duality. Surprisingly, we find that, in this system, the helical edge states are, in fact, protected by this fermionic-like pseudo time-reversal symmetry Tp rather than by the bosonic time-reversal symmetry Tb This remarkable finding is expected to pave a new path to understanding the symmetry protection mechanism for topological phases of other fundamental particles and to searching for novel implementations for topological insulators.

An acoustic asymmetric transmission device exhibiting unidirectional transmission property for acoustic waves is extremely desirable in many practical scenarios. Such a unique property may be realized in various configurations utilizing acoustic Zeeman effects in moving media as well as frequency-conversion in passive nonlinear acoustic systems and in active acoustic systems. Here we demonstrate a new acoustic frequency conversion process in a time-varying system, consisting of a rotating blade and the surrounding air. The scattered acoustic waves from this time-varying system experience frequency shifts, which are linearly dependent on the blade's rotating frequency. Such scattering mechanism can be well described theoretically by an acoustic linear time-varying perturbation theory. Combining such time-varying scattering effects with highly efficient acoustic filtering, we successfully develop a tunable acoustic unidirectional device with 20 dB power transmission contrast ratio between two counter propagation directions at audible frequencies.

Artificial honeycomb lattices with Dirac cone dispersion provide a macroscopic platform to study the massless Dirac quasiparticles and their novel geometric phases. In this paper, a quadruple-degenerate state is achieved at the center of the Brillouin zone in a two-dimensional honeycomb lattice phononic crystal, which is a result of accidental degeneracy of two double-degenerate states. In the vicinity of the quadruple-degenerate state, the dispersion relation is linear. Such quadruple degeneracy is analyzed by rigorous representation theory of groups. Using k·p method, a reduced Hamiltonian is obtained to describe the linear Dirac dispersion relations of this quadruple-degenerate state, which is well consistent with the simulation results. Near such accidental degeneracy, we observe some unique properties in wave propagating, such as defect-insensitive propagating character and the Talbot effect.

We study the nonreciprocal Tamm plasmon polaritons (TPPs) inside the light cone, which can be directly excited at the interface between the one-dimensional photonic crystal (1DPC) and magneto-optical (MO) metal film. Applying an external magnetic field on the MO metal, the broken time-reversal symmetry gives rise to such nonreciprocal electrons oscillation mediated plasmon mode. Separately exciting the forward and backward TPPs, light can be transmitted and reflected in one-way. An analytic dispersion relation based on admittance-matching approach is obtained. This design offers promising potential in realizing the optical diode.

Based on fluorescence and absorbance spectroscopy, the photophysical properties and mechanisms of novel organic europium (III) complexes in the case of different concentration in ethanol solution and solid flour were studied at room temperature. It was found that the complex absorption spectra are mainly due to the Phenanthroline ligand, gradually exhibit saturated absorption from shortwave to long wave with the concentration increased, and stretch and broaden to long wave. And four characteristic peaks of the fluorescence spectra are all emission spectra of Eu3+ in the complex, and the strongest emission wavelength was 617 nm corresponding to the (5)D0-->(7)F2 transition of Eu2+. And then, it is presented that the perturbation of acetanil ligand changes the parity state of Eu3+ energy field, resulting in the increase of (5)D0-->(7)F2 transition probability, making phenanthroline transfer its energy absorbed to Eu3+, and inducing 617nm strong emission of fluorescence peak.