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The surface of three-dimensional materials provides an ideal and versatile platform to explore quantum-confined physics. Here, we systematically investigate the electronic structure of Na-intercalated CrTe2, a van der Waals antiferromagnet, using angle-resolved photoemission spectroscopy and ab initio calculations. The measured band structure deviates from the calculation of bulk NaCrTe2 but agrees with that of ferromagnetic monolayer CrTe2. Consistently, we observe unexpected exchange splitting of the band dispersions, persisting well above the Néel temperature of bulk NaCrTe2. We argue that NaCrTe2 features a quantum-confined 2D ferromagnetic state in the topmost surface layer due to strong ferromagnetic correlation in the CrTe2 layer. Moreover, the exchange splitting and the critical temperature can be controlled by surface doping of alkali-metal atoms, suggesting the feasibility of tuning the surface ferromagnetism. Our work not only presents a simple platform for exploring tunable 2D ferromagnetism but also provides important insights into the quantum-confined low-dimensional magnetic states.
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Interface design has enormous potential for the enhancement of interfacial polarization and microwave absorption properties. However, the construction of interfaces is always limited in components of a single dimension. Developing systematic strategies to customize multidimensional interfaces and fully utilize advantages of low-dimensional materials remains challenging. Two-dimensional transition metal dichalcogenides (TMDCs) have garnered significant attention owing to their distinctive electrical conductivity and exceptional interfacial effects. In this study, a series of hollow TMDCs@C fibers are synthesized via sacrificial template of CdS and confined growth of TMDCs embedded in the fibers. The complex permittivity of the hollow TMDCs@C fibers can be adjusted by tuning the content of CdS templates. Importantly, the multidimensional interfaces of the fibers contribute to elevating the microwave absorption performance. Among the hollow TMDCs@C fibers, the minimum reflection loss (RLmin) of the hollow MoS2@C fibers can reach -52.0 dB at the thickness of 2.5 mm, with a broad effective absorption bandwidth of 4.56 GHz at 2.0 mm. This work establishes an alternative approach for constructing multidimensional coupling interfaces and optimizing TMDCs as microwave absorption materials.
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BACKGROUND: Cognitive and emotional impairment are among the core features of schizophrenia; assessment of vocal emotion recognition may facilitate the detection of schizophrenia. We explored the differences between cognitive and social aspects of emotion using vocal emotion recognition and detailed clinical characterization. METHODS: Clinical symptoms and social and cognitive functioning were assessed by trained clinical psychiatrists. A vocal emotion perception test, including an assessment of emotion recognition and emotional intensity, was conducted. One-hundred-six patients with schizophrenia (SCZ) and 230 healthy controls (HCs) were recruited. RESULTS: Considering emotion recognition, scores for all emotion categories were significantly lower in SCZ compared to HC. Considering emotional intensity, scores for anger, calmness, sadness, and surprise were significantly lower in the SCZs. Vocal recognition patterns showed a trend of unification and simplification in SCZs. A direct correlation was confirmed between vocal recognition impairment and cognition. In diagnostic tests, only the total score of vocal emotion recognition was a reliable index for the presence of schizophrenia. CONCLUSIONS: This study shows that patients with schizophrenia are characterized by impaired vocal emotion perception. Furthermore, explicit and implicit vocal emotion perception processing in individuals with schizophrenia are viewed as distinct entities. This study provides a voice recognition tool to facilitate and improve the diagnosis of schizophrenia.
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Esquizofrenia , Humanos , Esquizofrenia/diagnóstico , Emociones , Cognición , Ira , Percepción , Expresión Facial , Percepción SocialRESUMEN
Rashba spin-orbit coupling (SOC) could facilitate an efficient interconversion between spin and charge currents. Among various systems, BiTeI holds one of the largest Rashba-type spin splittings. Unlike other Rashba systems (e.g., Bi/Ag and Bi2Se3), an experimental investigation of the spin-to-charge interconversion in BiTeI remains to be explored. Through performing an angle-resolved photoemission spectroscopy (ARPES) measurement, such a large Rashba-type spin splitting with a Rashba parameter αR = 3.68 eV Å is directly identified. By studying the spin pumping effect in the BiTeI/NiFe bilayer, we reveal a very large inverse Rashba-Edelstein length λIREE ≈ 1.92 nm of BiTeI at room temperature. Furthermore, the λIREE monotonously increases to 5.00 nm at 60 K, indicating an enhanced Rashba SOC at low temperature. These results suggest that BiTeI films with the giant Rashba SOC are promising for achieving efficient spin-to-charge interconversion, which could be implemented for building low-power-consumption spin-orbitronic devices.
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Ultrathin films of intrinsic magnetic topological insulator MnBi2Te4 exhibit fascinating quantum properties such as the quantum anomalous Hall effect and the axion insulator state. In this work, we systematically investigate the evolution of the electronic structure of MnBi2Te4 thin films. With increasing film thickness, the electronic structure changes from an insulator type with a large energy gap to one with in-gap topological surface states, which is, however, still in drastic contrast to the bulk material. By surface doping of alkali-metal atoms, a Rashba split band gradually emerges and hybridizes with topological surface states, which not only reconciles the puzzling difference between the electronic structures of the bulk and thin-film MnBi2Te4 but also provides an interesting platform to establish Rashba ferromagnet that is attractive for (quantum) anomalous Hall effect. Our results provide important insights into the understanding and engineering of the intriguing quantum properties of MnBi2Te4 thin films.
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Nonlinearity of electroosmotic flows (EOFs) is ubiquitous and plays a crucial role in ion transport, specimen mixing, electrochemistry reaction, and electric energy storage and utilization. When and how the transition from a linear regime to a nonlinear one occurs is essential for understanding, prohibiting, or utilizing nonlinear EOF. However, due to the lack of reliable experimental instruments with high spatial and temporal resolutions, the investigation of the onset of nonlinear EOF still remains in theory. Herein, we experimentally studied the velocity fluctuations of EOFs driven by an alternating current (AC) electric field via ultrasensitive fluorescent blinking tricks. The linear and nonlinear AC EOFs are successfully identified from both the time trace and energy spectra of velocity fluctuations. The transitional electric field (EA,C) is determined by both the convection velocity (U) and AC frequency (ff) as EA,C â¼ ff0.48-0.027U. We hope the current investigation could be essential in the development of both theory and applications of nonlinear EOFs.
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Electricidad , Electroósmosis , Electroquímica , Transporte IónicoRESUMEN
BACKGROUND: Associations of air pollution with anxiety and depression were found in previous studies. However, whether air pollution exposure during pregnancy contributes to prenatal anxiety and depression or not is under-investigated. In this study, we aimed to analyze associations between fine particulate matter (PM2.5) exposure with anxiety and depression during pregnancy and to explore the critical window of PM2.5 exposure. METHODS: This study was based on the Shanghai Maternal-Child Pairs Cohort (Shanghai MCPC). We used a gap-filling random forest model to estimate PM2.5 exposure concentration during pregnancy of each participant. The Self-Rating Anxiety Scale (SAS) and the Center for Epidemiological Survey-Depression Scale (CES-D) were used to quantify the anxiety and depression levels in late pregnancy. Covariate information was obtained from medical records and questionnaires. We performed generalized linear regression and logistic regression models to assess the association and the critical window. RESULTS: Totally 3731 pregnant women were included, with the age of 28.85 ± 3.97 years old. Anxiety and depression rates were 10.8 % and 11.5 % respectively, according to the cut-off value of SAS and CES-D. Generalized linear regression results showed that the increase of PM2.5 concentration in three stages (gestational 0-13 weeks, 0-26 weeks, 0-36 weeks) was related to the increase of scale score. The PM2.5 concentration in 0-13 weeks could increase the risk of anxiety and depression by approximately 23 % and 25 %, respectively. And the gestational weeks 4th-13th were the suspicious critical window of PM2.5 exposure. CONCLUSION: The increased risk of anxiety or depression was related to PM2.5 exposure during pregnancy, especially early pregnancy.
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Depresión , Mujeres Embarazadas , Humanos , Femenino , Embarazo , Adulto Joven , Adulto , Depresión/epidemiología , China/epidemiología , Ansiedad/epidemiología , Vitaminas , Material Particulado/efectos adversosRESUMEN
Giant ragweed (Ambrosia trifida L.), an invasive weed, has an expanding distribution area and has recently started to spread in grasslands. This unusual event threatens grasslands worldwide. In this study, we aimed to evaluate the changes in the grassland soil seed banks caused by the giant ragweed invasion in Yili Valley, Xinjiang, China. Using the space-for-time substitution approach, we compared and quantified the soil seed bank communities in a grassland over eight years following giant ragweed invasion and after its removal. The results showed that the duration of invasion determined whether giant ragweed might pose a significant threat to the native seed bank community. Four years after the invasion, the in-site seed bank density of native community significantly decreased (30.44%), while the relative coverage of giant ragweed aboveground reached 83.75%. Furthermore, the species richness in the seed bank decreased significantly (12.36%), while the relative coverage of giant ragweed reached 100% six years after the invasion. Eight years after the invasion, the seed bank density and species richness of the native community decreased by 83.28% and 39.33%, respectively, whereby the seed banks tended to be homogeneous. After the removal of giant ragweed, the potential for regeneration was limited by the residual seed bank densities of the native community. Although the native seed bank density had increased significantly after three years of restoration, new growth was dominated by weedy species, rather than by the distinctive components of the grassland habitat. Our study clarifies the process by which giant ragweed causes damage to grasslands and serves as a reference for grassland restoration and management efforts.
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Banco de Semillas , Suelo , Ambrosia , Ecosistema , Pradera , SemillasRESUMEN
Multicomponent reactions that involve interception of onium ylides through Aldol, Mannich, and Michael addition with corresponding bench-stable acceptors have demonstrated broad applications in synthetic chemistry. However, because of the high reactivity and transient survival of these in situ generated intermediates, the substitution-type interception process, especially the asymmetric catalytic version, remains hitherto unknown. Herein, a three-component asymmetric allylation of α-diazo carbonyl compounds with alcohols and allyl carbonates is disclosed by employing a ternary cooperative catalysis of achiral Pd-complex, Rh2(OAc)4, and chiral phosphoric acid CPA. This method represents the first example of three-component asymmetric allylic alkylation through an SN1-type trapping process, which involves a convergent assembly of two active intermediates, Pd-allyl species, and enol derived from onium ylides, providing an expeditious access to chiral α,α-disubstituted ketones in good to high yields with high to excellent enantioselectivity. Combined experimental and computational studies have shed light on the mechanism of this novel three-component reaction, including the critical role of Xantphos ligand and the origin of enantioselectivity.
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An external-photocatalyst-free, light-driven alkylative ring-opening of stable spiroindolines was developed to construct indolo- and benzoannulated eight-membered lactams. The spiroindolines were prepared from tetrahydro-ß-carbolines by a dearomative Heck reaction. Mechanistic experimental studies on the alkylative ring opening suggested that a photoredox pathway was involved, in which the spiroindoline performed as both reagent and photosensitizer. DFT calculations showed that the radical addition toward a cyclic alkene was the key to the diastereoselective formation of tetracyclic medium-sized lactams.
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The convenient cross-coupling of sp2 or sp3 carbons with a specific boron vertex on carborane cage represents significant synthetic values and insurmountable challenges. In this work, we report an Rh-catalyzed reaction between o-carborane and N-acyl-glutarimides to construct various Bcage -C bonds. Under the optimized condition, the removable imine directing group (DG) leads to B(3)- or B(3,6)-C couplings, while the pyridyl DG leads to B(3,5)-Ar coupling. In particular, an unexpected rearrangement of amide reagent is observed in pyridyl directed B(4)-C(sp3 ) formation. This scalable protocol has many advantages, including easy access, the use of cheap and widely available coupling agents, no requirement of an external ligand, base or oxidant, high efficiency, and a broad substrate scope. Leveraging the RhI dimer and twisted amides, this method enables straightforward access to diversely substituted and therapeutically important carborane derivatives at boron site, and provides a highly valuable vista for carborane-based drug screening.
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A visible-light-driven radical silylative cyclization of aza-1,6-dienes featuring an acrylonitrile or acrylate moiety and an electron-neutral olefin was developed, which allows for stereoselective synthesis of densely functionalized piperidines in a highly atom-economical manner. Depending on the substitution pattern of the electron-neutral olefin, poor-to-excellent diastereoselectivity was observed. It was suggested that the 6-exo-trig cyclization was initiated by a chemoselective addition of silyl radical toward electron-deficient olefin and the geometry of the remaining olefin is closely associated with the cis-stereoselectivity. DFT calculations supported that a transition state with a cyano group locating at the axial position of the forming piperidine ring might be involved, in which either the increase of 1,3-diaxial repulsion or the lack of hydrogen bonding interaction will diminish diastereoselectivity.
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Because genetic variants in microRNAs (miRNAs) or their surrounding regions can alter miRNA processing, expression and final biological function, we investigated whether miRNA single-nucleotide polymorphisms (SNPs) are associated with cervical cancer (CC) susceptibility. Common miRNA SNPs (i.e. miR-146a rs2910164, miR-149 rs2292832, miR-196a2 rs11614913, miR-499 rs3746444, miR-605 rs2043556 and miR-618 rs2682818) were genotyped in the 954 patients and 1339 controls. The results showed that the miR-149 rs2292832 TC/CC genotypes were associated with a 21% increased risk of CC compared with the TT genotype [odds ratio (OR) = 1.21, 95% confidence interval (CI) = 1.00-1.47]. The association was more prominent among the subjects with age ≤ 48 years (OR = 1.55, 95% CI = 1.16-2.06), having history of abortion (OR = 1.44, 95% CI = 1.12-1.86), premenopausal status (OR = 1.41, 95% CI = 1.08-1.85) and patients with clinical stage II of CC (OR = 1.43, 95% CI = 1.08-1.90). The expression plasmids containing the pre-miR-149 sequence with C allele of rs2292832 transcribed higher amount of mature miR-149-5p/3p than these with T allele in the HeLa and SiHa cells. Therefore, the rs2292832 polymorphism might influence CC susceptibility through modulation of the procession of pre-miR-149 to mature miRNAs.
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MicroARNs/genética , Neoplasias del Cuello Uterino/genética , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Alelos , Pueblo Asiatico/genética , Carcinoma Adenoescamoso/genética , Carcinoma Adenoescamoso/metabolismo , Carcinoma Adenoescamoso/patología , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Femenino , Predisposición Genética a la Enfermedad , Células HeLa , Humanos , MicroARNs/metabolismo , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Factores de Riesgo , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patologíaRESUMEN
The recalcitrance of lignocellulosic biomass is a major factor limiting its conversion into biofuels. Therefore, in this study, we pretreated corn stalk with 2% Na2 CO3 and 2% H2 O2 for time 70 min at 130°C using a corn stalk to liquid ratio of 1:10. The fermentation broth from multicopy Saccharomyces cerevisiae strains engineered for lignocellulase synthesis was used to enzymatically hydrolyze the pretreated corn stalk. The highest monosaccharide yield (102 mmol/L) was obtained using 15 IU endocellulase, 10 IU exocellulase, and 15 IU ß-glucosidase per gram of cellulose and 20 IU xylanase per gram of hemicellulose. Subsequently, the high-efficiency ethanol-producing S. cerevisiae strain WXY12, which can produce ethanol from glucose and xylose simultaneously, was added to the fermentation system. The entire process involved ethanol production through simultaneous saccharification and fermentation (SSF). Optimization of the fermentation conditions (yeast powder as a nitrogen source, temperature of 30°C, MgSO4 as a metal ion inducer, rotation speed of 180 rpm, solid-liquid ratio of 1:8, and inoculation amount of 2%) resulted in an ethanol output of 46.87 g/L and a theoretical conversion rate of 27.4%. The results of this study improved corn stalk utilization, reduced hydrolysis costs, and generated high ethanol yields.
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Biocombustibles , Etanol/metabolismo , Fermentación , Saccharomyces cerevisiae/metabolismo , Zea mays/química , Zea mays/metabolismo , Bioingeniería , Biomasa , Hidrólisis , Lignina/química , Lignina/metabolismo , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMEN
Hantavirus infection during pregnancy can influence both maternal and fetal outcomes. Here, we describe four cases of hemorrhagic fever with renal syndrome (HFRS) in pregnant Chinese women. The HFRS put these women at increased risk for severe illness, despite the patients' symptomologies in the onset phase were similar to those observed in non-pregnant HFRS patients, such as fever, headache, nausea, and thrombocytopenia. Pregnant women appeared to have a more severe status, presenting with severe complications, such as hypervolemia and pulmonary edema. Nevertheless, with appropriate management, mothers with HFRS may carry to full-term and breastfeeding maybe safe and feasible.
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Virus Hantaan/aislamiento & purificación , Fiebre Hemorrágica con Síndrome Renal/virología , Riñón/virología , Complicaciones Infecciosas del Embarazo/virología , Adulto , Anticuerpos Antivirales/sangre , China/epidemiología , Femenino , Fiebre , Fiebre Hemorrágica con Síndrome Renal/epidemiología , Humanos , Riñón/fisiopatología , Embarazo , Adulto JovenRESUMEN
A supramolecular polycatenane stabilized by outer surface interactions between cucurbit[6]uril (Q[6] or CB[6]) cations and [CdCl4 ]2- is reported. The arrangement of the poly-interlocked supramolecular framework is evidently constructed by a favorable combination of weak non-covalent interactions such as hydrophobic effects, hydrogen bonding, ion-dipole interactions, and C-Hâ â â Cl interactions in the solid state. Further study suggests that such 3D poly-interlocked species could be rapidly precipitated from the mixture solution in high yield owing to electrostatic interaction of the [CdCl4 ]2- anion with the electropositive outer surface of Q[6] host. This work thus demonstrates a simple, low-cost, and efficient non-covalent approach for the construction of a infinite 3D interlocked structure in water besides through coordination or covalent bonds.
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The host-guest complexation of symmetrical di-cyclohexanocucurbit[6]uril (Cy2Q[6]) and hexa-cyclohexanocucurbit[6]uril (Cy6Q[6]) with a series of alkyldiammonium ions (H(3+)N(CH(2))nNH(3+), n = 2-8) has been studied both in solution and in the gas phase. (1)H NMR data indicate that all alkyldiammonium ions have inclusion interactions with both hosts except for the ethanediammonium ion. In addition, if the alkyl chain of the alkyldiammonium ion is longer than n = 5 methylene groups, compressed conformation may occur, which depends on the cavity shape of the hosts and the length of the alkyl chain. Isothermal titration calorimetry (ITC) studies point out that the host-guest complexations of both hosts with the latter five alkyldiammonium ions are enthalpically driven. The comparison of the thermodynamic data reveals that the enthalpies of the van der Waals interactions contribute more to the host-guest complexation enthalpy than the ion-dipole interactions. The enthalpic gain arises from the van der Waals interactions and the reduction of entropy upon the host-guest complexation is strongly affected by the cavity shape of the host. Gas phase structures of long alkyldiammonium guests within both hosts are completely different from those in aqueous solution.
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Control of surface wettability is needed in many applications. The potential use of 3D printing technology to gain control over wettability remains largely unexplored. In this paper, Fused Deposition Molding (FDM) 3D printing technology was utilized to print polylactic acid (PLA) microplate array structures to generate superhydrophobic surfaces with reversable wetting properties. This was achieved by spraying polydimethylsiloxane (PDMS) and silica (SiO2) solutions, over microplate surfaces. Anisotropic wetting properties were also achieved based on the surface structure design. Due to the shape memory properties of PLA, the morphology of the microplate arrays could be switched between the original upright shape and deformed shape. Through alternating pressing and heating treatments, the microplate arrays showed anisotropic wettability switching. The difference between the contact angle (CA) and sliding angle (SA) of water droplets on the original surface parallel to and perpendicular to the microplate array direction were ΔCA = 7° and ΔSA = 3° respectively, and those on the surface of the deformed microplate array were ΔCA = 7° and ΔSA = 21°, respectively. This process enabled reversible alteration in the wetting behavior of water droplets on the original and deformed surfaces between sliding and sticking states. PLA-based shape memory anisotropic superhydrophobic surfaces with tunable adhesion were successfully applied to rewritable platforms, micro droplet reaction platforms, and gas sensing.
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Blumea balsamifera (L.) DC., an important economic and medicinal herb, has a long history of being used as a traditional Chinese medicine. Its leaves have always been used as a raw material for the extraction of essential oils, comprising large amounts of terpenoids, which have good therapeutic effects on many diseases, such as eczema, bacterial infection, and hypertension. However, the genetic basis of terpenoid biosynthesis in this plant is virtually unknown on account of the lack of genomic data. Here, a combination of next-generation sequencing (NGS) and full-length transcriptome sequencing was applied to identify genes involved in terpenoid biosynthesis at five developmental stages. Then, the main components of essential oils in B. balsamifera were identified using GC-MS. Overall, 16 monoterpenoids and 20 sesquiterpenoids were identified and 333,860 CCS reads were generated, yielding 65,045 non-redundant transcripts. Among these highly accurate transcripts, 59,958 (92.18%) transcripts were successfully annotated using NR, eggNOG, Swissprot, KEGG, KOG, COG, Pfam, and GO databases. Finally, a total of 56 differently expressed genes (DEGs) involved in terpenoid biosynthesis were identified, including 38 terpenoid backbone genes and 18 TPSs, which provide a significant amount of genetic information for B. balsamifera. These results build a basis for resource protection, molecular breeding, and the metabolic engineering of this plant.