SIRT6 prevent chronic cerebral hypoperfusion induced cognitive impairment by remodeling mitochondrial dynamics in a STAT5-PGAM5-Drp1 dependent manner.

Vascular dementia (VaD) is a prevalent form of dementia resulting from chronic cerebral hypoperfusion (CCH). However, the pathogenic mechanisms of VaD and corresponding therapeutic strategies are not well understood. Sirtuin 6 (SIRT6) has been implicated in various biological processes, including cellular metabolism, DNA repair, redox homeostasis, and aging. Nevertheless, its functional relevance in VaD remains unexplored. In this study, we utilized a bilateral common carotid artery stenosis (BCAS) mouse model of VaD to investigate the role of SIRT6. We detected a significant decrease in neuronal SIRT6 protein expression following CCH. Intriguingly, neuron-specific ablation of Sirt6 in mice exacerbated neuronal damage and cognitive deficits after CCH. Conversely, treatment with MDL-800, an agonist of SIRT6, effectively mitigated neuronal loss and facilitated neurological recovery. Mechanistically, SIRT6 inhibited excessive mitochondrial fission by suppressing the CCH-induced STAT5-PGAM5-Drp1 signaling cascade. Additionally, the gene expression of monocyte SIRT6 in patients with asymptomatic carotid stenosis showed a correlation with cognitive outcomes, suggesting translational implications in human subjects. Our findings provide the first evidence that SIRT6 prevents cognitive impairment induced by CCH, and mechanistically, this protection is achieved through the remodeling of mitochondrial dynamics in a STAT5-PGAM5-Drp1-dependent manner.

Local Excitation of Kagome Spin Ice Magnetism Seen by Scanning Tunneling Microscopy.

The kagome spin ice can host frustrated magnetic excitations by flipping its local spin. Under an inelastic tunneling condition, the tip in a scanning tunneling microscope can flip the local spin, and we apply this technique to kagome metal HoAgGe with a long-range ordered spin ice ground state. Away from defects, we discover a pair of pronounced dips in the local tunneling spectrum at symmetrical bias voltages with negative intensity values, serving as a striking inelastic tunneling signal. This signal disappears above the spin ice formation temperature and has a dependence on the magnetic fields, demonstrating its intimate relation with the spin ice magnetism. We provide a two-level spin-flip model to explain the tunneling dips considering the spin ice magnetism under spin-orbit coupling. Our results uncover a local emergent excitation of spin ice magnetism in a kagome metal, suggesting that local electrical field induced spin flip climbs over a barrier caused by spin-orbital locking.

Factors associated with clinical nurse's mental health: a qualitative study applying the social ecological model.

BACKGROUND: The prevalence of burnout, depression, and anxiety among Chinese nurses was 34%, 55.5%, and 41.8% respectively. Mental health problems have significant impacts on their personal well-being, work performance, patient care quality, and the overall healthcare system. Mental health is influenced by factors at multiple levels and their interactions. METHODS: This was a descriptive qualitative study using phenomenological approach. We recruited a total of 48 nurses from a tertiary hospital in Changsha, Hunan Province, China. Data were collected through focus group interviews. Audio-recorded data were transcribed and inductively analysed. RESULTS: Four major themes with 13 subthemes were identified according to the social ecological model: (1) individual-level factors, including personality traits, sleep quality, workplace adaptability, and years of work experience; (2) interpersonal-level factors, encompassing interpersonal support and role conflict; (3) organization-level factors, such as organizational climate, organizational support, career plateau, and job control; and (4) social-level factors, which included compensation packages, social status, and legislative provision and policy. CONCLUSIONS: Our study provides a nuanced understanding of the multifaceted factors influencing nurses' mental health. Recognizing the interconnectedness of individual, interpersonal, organizational, and social elements is essential for developing targeted interventions and comprehensive strategies to promote and safeguard the mental well-being of nurses in clinical settings. TRIAL AND PROTOCOL REGISTRATION: The larger study was registered with Chinese Clinical Trial Registry: ChiCTR2300072142 (05/06/2023) https://www.chictr.org.cn/showproj.html?proj=192676 . REPORTING METHOD: This study is reported according to the Consolidated Criteria for Reporting Qualitative Research (COREQ).

Cobalt-Induced Phase Transformation of Ni3Ga4 Generates Chiral Intermetallic Co3Ni3Ga8.

The scientific community has found immense difficulty to focus on the generation of chiral intermetallics compared to the chiral molecular structure, probably due to the technical difficulty in producing them as no general controlled protocol is available. Herein, using a conventional metal flux technique, we have discovered a new ternary intermetallic Co3Ni3Ga8, substituting Co at the Ni sublattice in a highly symmetric Ni3Ga4 (Ia3̅d). Co3Ni3Ga8 crystallizes in the I4132 space group, a Sohncke type, and can host the chiral structure. To the best of our knowledge, this is the first report of a ternary intermetallic crystallizing in this space group. The chiral structure of Co3Ni3Ga8 is comprehensively mapped by various techniques such as single-crystal X-ray diffraction (XRD), synchrotron powder XRD, X-ray absorption spectroscopy (XAS), scanning transmission electron microscopy (STEM) and theoretically studied using density functional theory. The discovery of this chiral compound can inspire the researchers to design hidden ternary chiral intermetallics to study the exotic electrical and magnetic properties.

Anisotropic Growth of One-Dimensional Carbides in Single-Walled Carbon Nanotubes with Strong Interaction for Catalysis.

Tungsten and molybdenum carbides have shown great potential in catalysis and superconductivity. However, the synthesis of ultrathin W/Mo carbides with a controlled dimension and unique structure is still difficult. Here, inspired by the host-guest assembly strategy with single-walled carbon nanotubes (SWCNTs) as a transparent template, we reported the synthesis of ultrathin (0.8-2.0 nm) W2C and Mo2C nanowires confined in SWCNTs deriving from the encapsulated W/Mo polyoxometalate clusters. The atom-resolved electron microscope combined with spectroscopy and theoretical calculations revealed that the strong interaction between the highly carbophilic W/Mo and SWCNT resulted in the anisotropic growth of carbide nanowires along a specific crystal direction, accompanied by lattice strain and electron donation to the SWCNTs. The SWCNT template endowed carbides with resistance to H2O corrosion. Different from normal modification on the outer surface of SWCNTs, such M2C@SWCNTs (M = W, Mo) provided a delocalized and electron-enriched SWCNT surface to uniformly construct the negatively charged Pd catalyst, which was demonstrated to inhibit the formation of active PdHx hydride and thus achieve highly selective semihydrogenation of a series of alkynes. This work could provide a nondestructive way to design the electron-delocalized SWCNT surface and expand the methodology in synthesizing unusual 1D ultrathin carbophilic-metal nanowires (e.g., TaC, NbC, ß-W) with precise control of the anisotropy in SWCNT arrays.

High-entropy enhanced capacitive energy storage.

Electrostatic dielectric capacitors are essential components in advanced electronic and electrical power systems due to their ultrafast charging/discharging speed and high power density. A major challenge, however, is how to improve their energy densities to effectuate the next-generation applications that demand miniaturization and integration. Here, we report a high-entropy stabilized Bi2Ti2O7-based dielectric film that exhibits an energy density as high as 182 J cm-3 with an efficiency of 78% at an electric field of 6.35 MV cm-1. Our results reveal that regulating the atomic configurational entropy introduces favourable and stable microstructural features, including lattice distorted nano-crystalline grains and a disordered amorphous-like phase, which enhances the breakdown strength and reduces the polarization switching hysteresis, thus synergistically contributing to the energy storage performance. This high-entropy approach is expected to be widely applicable for the development of high-performance dielectrics.

Toll-like receptor may be involved in acquired immune response in pearl oyster Pinctada fucata.

The increasing experimental evidence suggests that there are some forms of specific acquired immunity in invertebrates, in which Toll-like receptors (TLRs) play vital roles in activating innate and adaptive immunity and have been comprehensively investigated in mammalian species. Yet, the immune mechanisms underlying TLR mediation in mollusks remain obscure. In this study, we identified a TLR13 gene in the pearl oyster Pinctada fucata for the first time and named it PfTLR13 which consists of a 5'-untranslated terminal region (5'-UTR) of 543 bp, an open reading frame (ORF) of 2667 bp, and a 3'-UTR of 729 bp. We found that PfTLR13 mRNA was expressed in all tissues examined, with the highest level in the gills. The expression of PfTLR13 in the gills of oysters exposed to Vibrio alginolyticus or pathogen-associated molecular patterns (PAMPs) (including LPS, PGN, and poly(I:C)) was significantly higher than in the control group. Interestingly, the immune response to the first stimulation was weaker than the response to the second stimulation, suggesting that the primary stimulation may lead to immune priming of TLR in pearl oysters, similar to acquired immunity in vertebrates. Furthermore, we found that PfTLR13 expression was differentially associated with allograft and xenograft in the pearl oyster P. fucata, with the highest expression levels observed at 12 h post-allograft and 24 h post-xenograft. Overall, our findings provide new insights into the immune mechanisms underlying TLR mediation in mollusks and suggest that PfTLR13 may play a crucial role in the specific acquired immunity of pearl oysters.

Magnetotransport signatures of Weyl physics and discrete scale invariance in the elemental semiconductor tellurium.

The study of topological materials possessing nontrivial band structures enables exploitation of relativistic physics and development of a spectrum of intriguing physical phenomena. However, previous studies of Weyl physics have been limited exclusively to semimetals. Here, via systematic magnetotransport measurements, two representative topological transport signatures of Weyl physics, the negative longitudinal magnetoresistance and the planar Hall effect, are observed in the elemental semiconductor tellurium. More strikingly, logarithmically periodic oscillations in both the magnetoresistance and Hall data are revealed beyond the quantum limit and found to share similar characteristics with those observed in ZrTe5 and HfTe5 The log-periodic oscillations originate from the formation of two-body quasi-bound states formed between Weyl fermions and opposite charge centers, the energies of which constitute a geometric series that matches the general feature of discrete scale invariance (DSI). Our discovery reveals the topological nature of tellurium and further confirms the universality of DSI in topological materials. Moreover, introduction of Weyl physics into semiconductors to develop "Weyl semiconductors" provides an ideal platform for manipulating fundamental Weyl fermionic behaviors and for designing future topological devices.

Abundance, characteristics, and removal of microplastics in the Cihu Lake-wetland microcosm system.

Sewage treatment plants (STPs) are significant routes through which microplastics (MPs) are released into the aquatic environment. Constructed wetland is an effective facility for deep treatment of tailwater. At present, research on the removal of MPs in the tailwater of STPs by multi-stage constructed wetlands is limited. This work investigated and analyzed the removal characteristics of MPs in the tailwater treatment system of Cihu wetland park in Huangshi, Hubei Province of China. The abundance/removal of MPs in the Cihu Lake-wetland microcosm system was investigated. The results showed that the multi-stage constructed wetlands achieved a total removal rate of 94.7% for MPs with 2.2 particles/L MPs in the effluent. The removal rates of MPs reached 89 and 37.5%, respectively, in the (horizontal/vertical) subsurface flow constructed wetland and surface flow constructed wetland. The abundance of MPs in receiving water of Cihu Lake substantially decreased due to the dilution of wetland effluents. This study partially bridged the knowledge gap hypothesis on the treatment of MPs in tailwater by multi-stage constructed wetlands.

Electric Polarization Switching on an Atomically Thin Metallic Oxide.

Materials with reduced dimensions have been shown to host a wide variety of exotic properties and novel quantum states that often defy textbook wisdom. Polarization switching and metallic screening are well-known examples of mutually exclusive properties that cannot coexist in bulk solids. Here we report the fabrication of (SrRuO3)1/(BaTiO3)10 superlattices that exhibits reversible polarization switching in an atomically thin metallic layer. A multipronged investigation combining structural analyses, electrical measurements, and first-principles electronic structure calculations unravels the coexistence of two-dimensional (2D) metallicity in the SrRuO3 layer accompanied by the breaking of inversion symmetry, supporting electric polarization along the out-of-plane direction. Such a 2D ferroelectric-like metal paves a novel way to engineer a quantum multistate with unusual coexisting properties, such as ferroelectrics and metals, manipulated by external fields.

Hierarchical Self-Assembly of Nanowires on the Surface by Metallo-Supramolecular Truncated Cuboctahedra.

Parastichy, the spiral arrangement of plant organs, is an example of the long-range apparent order seen in biological systems. These ordered arrangements provide scientists with both an aesthetic challenge and a mathematical inspiration. Synthetic efforts to replicate the regularity of parastichy may allow for molecular-scale control over particle arrangement processes. Here we report the packing of a supramolecular truncated cuboctahedron (TCO) into double-helical (DH) nanowires on a graphite surface with a non-natural parastichy pattern ascribed to the symmetry of the TCOs and interactions between TCOs. Such a study is expected to advance our understanding of the design inputs needed to create complex, but precisely controlled, hierarchical materials. It is also one of the few reported helical packing structures based on Platonic or Archimedean solids since the discovery of the Boerdijk-Coxeter helix. As such, it may provide experimental support for studies of packing theory at the molecular level.

Point Defect Engineering: Co-Doping Synergy Realizing Superior Performance in n-Type Bi2 Te3 Thermoelectric Materials.

Bi2 Te3 has attracted great attention because of its excellent thermoelectric (TE) performance around room temperature. However, the TE property of the n-type Bi2 Te3 is still relatively low compared to the p-type counterpart, which seriously hinders its commercial application with a combination of the n-type and p-type materials. Herein, an effective process of Cl and W co-doping is employed into the n-type Bi2 Te3 materials to enhance its TE properties. The Bi1.996 W0.004 Te2.476 Cl0.024 Se0.5 sample achieves a peak and average ZT over 1.3 and 1.2, respectively, at temperature range of 300-575 K. A 24-leg TE module of this n-type material and a home-made p-type Bi2 Te3 sample can produce a high efficiency over 6% at a temperature gradient of 235 K, which possesses a 71% improvement compared with a commercial Bi2 Te3 module. This high performance is ascribed to the effect of the Cl and W doping. This co-doping not only significantly increases the Grüneisen parameter but also successfully induces interstitial atoms in the van der Waals gap, which lead to a low lattice thermal conductivity (κl ) of 0.31W m-1 K-1 and a boosted charge transport. This finding represents an important step to promote the development of the n-type Bi2 Te3 materials.

Strained Endotaxial PbS Nanoprecipitates Boosting Ultrahigh Thermoelectric Quality Factor in n-Type PbTe As-Cast Ingots.

Lead telluride (PbTe) has long been regarded as an excellent thermoelectric material at intermediate temperature range (573-873 K); however, n-type PbTe's performance is always relatively inferior to its p-type counterpart mainly due to their different electronic band structures. In this work, an ultrahigh thermoelectric quality factor (µ/κL  ≈ 1.36 × 105 cm3 KJ-1 V-1 ) is reported in extra 0.3% Cu doped n-type (PbTe)0.9 (PbS)0.1 as-cast ingots. Transmission electron microscopy (TEM) characterization reveals that excess PbS exists in PbTe matrix as strained endotaxial nanoprecipitates, which affect electrical and thermal conduction discriminately: (1) coherent PbTe/PbS lattice minimizes the interface scattering of charge carriers; (2) periodic strain centers at PbTe/PbS interface exhibit intensive strain contrast, which can strongly scatter heat-carrying phonons. Electron backscattered diffraction (EBSD) characterization illustrates very large PbTe grains (≈1 mm) in these as-cast ingots, ensuring an extremely low grain boundary scattering rate thus a very high charge carrier mobility. Eventually, a remarkably high ZTmax  ≈ 1.5 at 773 K and an outstanding ZTavg  ≈ 1.0 between 323 and 773 K are simultaneously achieved in the (PbTe)0.9 (PbS)0.1  +0.3%Cu sample; these values are highly competitive with reported state-of-art n-type PbTe materials.

Flash Solid-Solid Synthesis of Silicon Oxide Nanorods.

1D silicon-based nanomaterials, renowned for their unique chemical and physical properties, have enabled the development of numerous advanced materials and biomedical technologies. Their production often necessitates complex and expensive equipment, requires hazardous precursors and demanding experimental conditions, and involves lengthy processes. Herein, a flash solid-solid (FSS) process is presented for the synthesis of silicon oxide nanorods completed within seconds. The innovative features of this FSS process include its simplicity, speed, and exclusive use of solid precursors, comprising hydrogen-terminated silicon nanosheets and a metal nitrate catalyst. Advanced electron microscopy and X-ray spectroscopy analyses favor a solid-liquid-solid reaction pathway for the growth of the silicon oxide nanorods with vapor-liquid-solid characteristics.

Nano-patterning of a monolayer molybdenum disulfide with sub-nanometer helium ion beam: considering its shape, size and damage.

We have studied nano-patterning of a two-dimensional (2D) material with an ultrafine helium ion beam considering shape-, size- and damage-control. The study reveals that the crystalline structure plays an important role in shape-control. Instead of commonly circular-shaped nanopores, spot irradiation onto a single layer of molybdenum disulfide (MoS2) gives rise to a rhombus-shaped nanopore, which is well explained by the sub-rhombus crystalline structure of MoS2. Helium ion beams also show promising capability to precisely control size using a delivered dose. However, the size of the nanopores is not linear with the delivered dose, due to the Gaussian distributed intensity profile of the helium ion beam. The intensity profiles are further estimated by considering aperture size, those results could be taken as a significant reference for size-control. In addition, we clarify that most of the damage is a result of re-deposition, thus controlling re-deposition might be a useful way to alleviate the damage.

Butterfly Wing Hears Sound: Acoustic Detection Using Biophotonic Nanostructure.

The biophotonic nanostructures of Morpho butterfly wing display iridescent colors through the combined effect of light diffraction and interference. These nanostructures have attracted wide attention due to their high optical sensitivity and deformable material properties and have been applied to various infrared (IR), volatile organic compound (VOC), and pH sensors. This work explores the application of such biophotonic nanostructures of butterfly wing for acoustic detection and voice recognition. The pressure variation of the acoustic waves induces the vibration of butterfly wing diaphragm, resulting in the periodic change of reflectance. The integrated butterfly wing-based acoustic sensor shows high fidelity in replicating the original acoustic signals. The sensor also demonstrates promise in distinguishing human voices, which provides an alternative approach for voice recognition.

Directing Gold Nanoparticles into Free-Standing Honeycomb-Like Ordered Mesoporous Superstructures.

2D mesoporous materials fabricated via the assembly of nanoparticles (NPs) not only possess the unique properties of nanoscale building blocks but also manifest additional collective properties due to the interactions between NPs. In this work, reported is a facile and designable way to prepare free-standing 2D mesoporous gold (Au) superstructures with a honeycomb-like configuration. During the fabrication process, Au NPs with an average diameter of 5.0 nm are assembled into a superlattice film on a diethylene glycol substrate. Then, a subsequent thermal treatment at 180 °C induces NP attachment, forming the honeycomb-like ordered mesoporous Au superstructures. Each individual NP connects with three neighboring NPs in the adjacent layer to form a tetrahedron-based framework. Mesopores confined in the superstructure have a uniform size of 3.5 nm and are arranged in an ordered hexagonal array. The metallic bonding between Au NPs increases the structural stability of architected superstructures, allowing them to be easily transferred to various substrates. In addition, electron energy-loss spectroscopy experiments and 3D finite-difference time-domain simulations reveal that electric field enhancement occurs at the confined mesopores when the superstructures are excited by light, showing their potential in nano-plasmonic applications.

N-type Bi-doped SnSe Thermoelectric Nanomaterials Synthesized by a Facile Solution Method.

An n-type Bi-doped SnSe was synthesized by a facile solution method followed by spark plasma sintering. We used bismuth(III) 2-ethyhexanoate as a cationic dopant precursor, which can absorb on the powder surface and then diffuse into the lattice to realize the substitution of Sn by Bi. A strip structure with low-angle boundary was constructed for effective phonon scattering. With increasing content of Bi, the carrier concentration decreased from 1.35 × 1019 cm-3 (p-type) in undoped SnSe to 4.7 × 1014 cm-3 (n-type) in Sn0.99Bi0.01Se and then increased to 1.3 × 1015 cm-3 (n-type) in Sn0.97Bi0.03Se. The Seebeck coefficient changed from positive to negative and presented n-type conducting behavior in the whole measured temperature range from 300 to 773 K, reaching a maximum absolute value of ∼900 µV K-1 at room temperature and ∼300 µV K-1 at 773 K. Considering the rich variety of metal 2-ethylhexanoates, higher thermoelectric performance is expected by different cationic doping in solution-synthesized nanomaterials.

Achieving high thermoelectric performance of Cu1.8S composites with WSe2 nanoparticles.

Polycrystalline p-type Cu1.8S composites with WSe2 nanoparticles were fabricated by the mechanical alloying method combined with the spark plasma sintering technique. The Seebeck coefficient was significantly enhanced by the optimized carrier concentration, while the thermal conductivity was simultaneously decreased due to the refined grain and WSe2 nanoparticles. An enhanced Seebeck coefficient of 110 µV K-1 and a reduced thermal conductivity of 0.68 W m-1 K-1 were obtained for the Cu1.8S + 1 wt% WSe2 sample at 773 K, resulting in a remarkably enhanced peak ZT of 1.22 at 773 K, which is 2.5 times higher than that (0.49 at 773 K) of a pristine Cu1.8S sample. The cheap and environmentally friendly Cu1.8S-based materials with enhanced properties may find promising applications in thermoelectric devices.

All-solid-state dye-sensitized solar cells with high efficiency.

Dye-sensitized solar cells based on titanium dioxide (TiO(2)) are promising low-cost alternatives to conventional solid-state photovoltaic devices based on materials such as Si, CdTe and CuIn(1-x)Ga(x)Se(2) (refs 1, 2). Despite offering relatively high conversion efficiencies for solar energy, typical dye-sensitized solar cells suffer from durability problems that result from their use of organic liquid electrolytes containing the iodide/tri-iodide redox couple, which causes serious problems such as electrode corrosion and electrolyte leakage. Replacements for iodine-based liquid electrolytes have been extensively studied, but the efficiencies of the resulting devices remain low. Here we show that the solution-processable p-type direct bandgap semiconductor CsSnI(3) can be used for hole conduction in lieu of a liquid electrolyte. The resulting solid-state dye-sensitized solar cells consist of CsSnI(2.95)F(0.05) doped with SnF(2), nanoporous TiO(2) and the dye N719, and show conversion efficiencies of up to 10.2 per cent (8.51 per cent with a mask). With a bandgap of 1.3 electronvolts, CsSnI(3) enhances visible light absorption on the red side of the spectrum to outperform the typical dye-sensitized solar cells in this spectral region.