Polar Bloch points in strained ferroelectric films.

Topological domain structures have drawn great attention as they have potential applications in future electronic devices. As an important concept linking the quantum and classical magnetism, a magnetic Bloch point, predicted in 1960s but not observed directly so far, is a singular point around which magnetization vectors orient to nearly all directions. Here we show polar Bloch points in tensile-strained ultrathin ferroelectric PbTiO3 films, which are alternatively visualized by phase-field simulations and aberration-corrected scanning transmission electron microscopic imaging. The phase-field simulations indicate local steady-state negative capacitance around the Bloch points. The observation of polar Bloch points and their emergent properties consequently implies novel applications in future integrated circuits and low power electronic devices.

Atomic Insight into the Successive Antiferroelectric-Ferroelectric Phase Transition in Antiferroelectric Oxides.

Antiferroelectrics characterized by voltage-driven reversible transitions between antiparallel and parallel polarity are promising for cutting-edge electronic and electrical power applications. Wide-ranging explorations revealing the macroscopic performances and microstructural characteristics of typical antiferroelectric systems have been conducted. However, the underlying mechanism has not yet been fully unraveled, which depends largely on the atomistic processes. Herein, based on atomic-resolution transmission electron microscopy, the deterministic phase transition pathway along with the underlying lattice-by-lattice details in lead zirconate thin films was elucidated. Specifically, we identified a new type of ferrielectric-like dipole configuration with both angular and amplitude modulations, which plays the role of a precursor for a subsequent antiferroelectric to ferroelectric transformation. With the participation of the ferrielectric-like phase, the phase transition pathways driven by the phase boundary have been revealed. We provide new insights into the consecutive phase transformation in low-dimensional lead zirconate, which thus would promote potential antiferroelectric-based multifunctional devices.

Achieving High-Temperature Multiferroism by Atomic Architecture.

Materials with multiple order parameters, typically, in which ferroelectricity and magnetism are coupled, are illuminative for next-generation multifunctional electronics. However, searching for such single-phase multiferroics is challenging owing to antagonistic orbital occupancy and chemical bonding requirements for polarity and magnetism. Appropriate multiferroic candidates have been proposed, but their practical implementation is impeded by the low working temperature, weak coupling between ferroic orders, or antiparallel spin alignment in magnetic sublattices. Here, we report a family of single-phase multiferroic materials in which high-temperature magnetism and voltage-switchable ferroelectricity are coupled. Using pulsed laser deposition, we have fabricated single-crystalline thin films incorporating a uniformly percolated open-shell dn framework, which are composed of Fe cations with B-site occupancy and exhibit long-range spin ordering into the displacive ferroelectric PbTiO3 lattice, as demonstrated by atomically resolved chemical analysis. The tetragonal polar Pb(Ti1-x,Fex)O3 (PFT(x), x ≤ 0.10) family exhibits a switchable ferroelectric nature and magnetic interaction with a moderate coercive field of around 300 Oe at room temperature. Notably, the magnetic order even persists above 500 K, which is higher than already reported potential multiferroic candidates until now. Our strategy of merging a spin-ordered sublattice into inherent ferroelectrics via atomic occupancy engineering provides an available pathway for highly thermally stable multiferroic and spintronic applications.

Real-Time Transformation of Flux-Closure Domains with Superhigh Thermal Stability.

Polar topologies have received extensive attention due to their exotic configurations and functionalities. Understanding their responsive behaviors to external stimuli, especially thermal excitation, is highly desirable to extend their applications to high temperature, which is still unclear. Here, combining in situ transmission electron microscopy and phase-field simulations, the thermal dynamics of the flux-closure domains were illuminated in PbTiO3/SrTiO3 multilayers. In-depth analyses suggested that the topological transition processes from a/c domains to flux-closure quadrants were influenced by the boundary conditions of PbTiO3 layers. The symmetrical boundary condition stabilized the flux-closure domains at higher temperature than in the asymmetrical case. Furthermore, the reversible thermal responsive behaviors of the flux-closure domains displayed superior thermal stability, which maintained robust up to 450 °C (near the Curie temperature). This work provides new insights into the dynamics of polar topologies under thermal excitation and facilitates their applications as nanoelectronics under extreme conditions.

Polar Magnetism Above 600 K with High Adaptability in Perovskite Oxides.

High magnetic order temperature, sustainable polar insulating state, and tolerance to device integrations are substantial advantages for applications in next-generation spintronics. However, engineering such functionality in a single-phase system remains a challenge owing to the contradicted chemical and electronic requirements for polar nature and magnetism, especially with an ordering state highly above room temperature. Perovskite-related oxides with unique flexibility allow electron-unpaired subsystems to merge into the polar lattice to induce magnetic interactions, combined with their inherent asymmetry, thereby promising polar magnet design. Herein, by atomic-level composition assembly, a family of Ti/Fe co-occupied perovskite oxide films Pb(Ti1-x,Fex)O3 (PFT(x)) with a Ruddlesden-Popper superstructure are successfully synthesized on several different substrates, demonstrating exceptional adaptability to different integration conditions. Furthermore, second-harmonic generation measurements convince the symmetry-breaking polar character. Notably, a ferromagnetic ground state up to 600 K and a steady insulating state far beyond room temperature were achieved simultaneously in these films. This strategy of constructing layered modular superlattices in perovskite oxides could be extended to other strongly correlated systems for triggering nontrivial quantum physical phenomena.

Differential Responses to Salt Stress in Four White Clover Genotypes Associated With Root Growth, Endogenous Polyamines Metabolism, and Sodium/Potassium Accumulation and Transport.

Selection and utilization of salt-tolerant crops are essential strategies for mitigating salinity damage to crop productivity with increasing soil salinization worldwide. This study was conducted to identify salt-tolerant white clover (Trifolium repens) genotypes among 37 materials based on a comprehensive evaluation of five physiological parameters, namely, chlorophyll (Chl) content, photochemical efficiency of PS II (Fv/Fm), performance index on an absorption basis (PIABS), and leaf relative water content (RWC), and to further analyze the potential mechanism of salt tolerance associated with changes in growth, photosynthetic performance, endogenous polyamine metabolism, and Na+/K+ uptake and transport. The results showed that significant variations in salt tolerance were identified among 37 genotypes, as PI237292 and Tr005 were the top two genotypes with the highest salt tolerance, and PI251432 and Korla were the most salt-sensitive genotypes compared to other materials. The salt-tolerant PI237292 and Tr005 not only maintained significantly lower EL but also showed significantly better photosynthetic performance, higher leaf RWC, underground dry weight, and the root to shoot ratio than the salt-sensitive PI251432 and Korla under salt stress. Increases in endogenous PAs, putrescine (Put), and spermidine (Spd) contents could be key adaptive responses to salt stress in the PI237292 and the Tr005 through upregulating genes encoding Put and Spd biosynthesis (NCA, ADC, SAMDC, and SPDS2). For Na+ and K+ accumulation and transport, higher salt tolerance of the PI237292 could be associated with the maintenance of Na+ and Ca+ homeostasis associated with upregulations of NCLX and BTB/POZ. The K+ homeostasis-related genes (KEA2, HAK25, SKOR, POT2/8/11, TPK3/5, and AKT1/5) are differentially expressed among four genotypes under salt stress. However, the K+ level and K+/Na+ ratio were not completely consistent with the salt tolerance of the four genotypes. The regulatory function of these differentially expressed genes (DEGs) on salt tolerance in the white clover and other leguminous plants needs to be investigated further. The current findings also provide basic genotypes for molecular-based breeding for salt tolerance in white clover species.

Magneto-Electric-Optical Coupling in Multiferroic BiFeO3 -Based Films.

Manipulating ferroic orders and realizing their coupling in multiferroics at room temperature are promising for designing future multifunctional devices. Single external stimulation has been extensively proved to demonstrate the ability of ferroelastic switching in multiferroic oxides, which is crucial to bridge the ferroelectricity and magnetism. However, it is still challenging to directly realize multi-field-driven magnetoelectric coupling in multiferroic oxides as potential multifunctional electrical devices. Here, novel magneto-electric-optical coupling in multiferroic BiFeO3 -based thin films at room temperature mediated by deterministic ferroelastic switching using piezoresponse/magnetic force microscopy and aberration-corrected transmission electron microscopy are shown. Reversible photoinduced ferroelastic switching exhibiting magnetoelectric responses is confirmed in BiFeO3 -based films, which works at flexible strain states. This work directly demonstrates room-temperature magneto-electric-optical coupling in multiferroic films, which provides a framework for designing potential multi-field-driven magnetoelectric devices such as energy conservation memories.

[Determination of eight active components of Bufei Huoxue Capsules in rat plasma and their pharmacokinetics by UHPLC-MS/MS].

An ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS) method was established to investigate the pharmacokinetic behaviors of psoralenoside, isopsoralenoside, calycosin-7-glucoside, ononin, psoralen, isopsoralen, methylnissolin, and neobavaisoflavone in rat plasma after oral administration of Bufei Huoxue Capsules. After SD rats were administered with Bufei Huoxue Capsules suspension by gavage, blood samples were collected from the inner canthus at different time points. After protein precipitation, plasma samples were separated on ACQUITY UPLC BEH C_(18) column(2.1 mm×100 mm, 1.7 µm). The mobile phase consisted of acetonitrile(A) and water(B) containing 0.1% formic acid in gradient elution. The positive and negative ions were measured simultaneously in the multi-reaction monitoring(MRM) mode. The pharmacokinetic parameters were calculated and fitted by DAS 3.2.8. Psoralenoside, isopsoralenoside, calycosin-7-glucoside, ononin, psoralen, isopsoralen, methylnissolin, and neobavaisoflavone were detected in the rat plasma after drug administration, with AUC_(0-t) of(3 357±1 348),(3 555±1 696),(3.03±0.88),(2.21±0.33),(1 787±522),(2 295±539),(5.69±1.41) and(3.40±0.75) µg·L~(-1)·h, and T_(max) of(1.56±0.62),(1.40±0.70),(0.21±0.05),(0.25±0.12),(0.26±0.11),(0.34±0.29),(0.74±0.59), and 0.25 h. The method is proved specific and repeatable and is suitable for the determination of psoralenoside, isopsoralenoside, calycosin-7-glucoside, ononin, pso-ralen, isopsoralen, methylnissolin, and neobavaisoflavone in the rat plasma, which can be applied to pharmacokinetic study.

Diethyl Aminoethyl Hexanoate Priming Ameliorates Seed Germination via Involvement in Hormonal Changes, Osmotic Adjustment, and Dehydrins Accumulation in White Clover Under Drought Stress.

Drought is a serious outcome of climate change reducing the productivity of forage species under arid and semi-arid conditions worldwide. Diethyl aminoethyl hexanoate (DA-6), a novel plant growth regulator, has proven to be involved in the amelioration of critical physiological functions in many agricultural crops under various abiotic stresses, but the role of the DA-6 in improving seed germination has never been investigated under drought stress. The present study was carried out to elucidate the impact of the DA-6 priming on seeds germination of white clover under drought stress. Results showed that seed priming with the DA-6 significantly mitigated the drought-induced reduction in germination percentage, germination vigor, germination index, seed vigor index, root length, shoot length, and fresh weight after 7 days of seed germination. The DA-6 significantly increased the endogenous indole-3-acetic acid, gibberellin, and cytokinin content with marked reduction in abscisic acid content in seedlings under drought stress. In addition, the DA-6 significantly accelerated starch catabolism by enhancing the activities of hydrolases contributing toward enhanced soluble sugars, proline content and ameliorated the antioxidant defense system to enhance the ability of reactive oxygen species scavenging under drought stress. Furthermore, exogenous DA-6 application significantly increased dehydrins accumulation and upregulated transcript levels of genes encoding dehydrins (SK2, Y2SK, or DHNb) during seeds germination under water deficient condition. These findings suggested that the DA-6 mediated seeds germination and drought tolerance associated with changes in endogenous phytohormones resulting in increased starch degradation, osmotic adjustment, antioxidants activity, and dehydrins accumulation during seed germination under water deficient condition.

Atomic mapping of periodic dipole waves in ferroelectric oxide.

A dipole wave is composed of head-to-tail connected electric dipoles in the form of sine function. Potential applications in information carrying, transporting, and processing are expected, and logic circuits based on nonlinear wave interaction are promising for dipole waves. Although similar spin waves are well known in ferromagnetic materials for their roles in some physical essence, electric dipole wave behavior and even its existence in ferroelectric materials are still elusive. Here, we observe the atomic morphology of large-scale dipole waves in PbTiO3/SrTiO3 superlattice mediated by tensile epitaxial strains on scandate substrates. The dipole waves can be expressed in the formula of y = Asin (2πx/L) + y 0, where the wave amplitude (A) and wavelength (L) correspond to 1.5 and 6.6 nm, respectively. This study suggests that by engineering strain at the nanoscale, it should be possible to fabricate unknown polar textures, which could facilitate the development of nanoscale ferroelectric devices.

Th17 cells are involved in mouse chronic obstructive pulmonary disease complicated with invasive pulmonary aspergillosis.

BACKGROUND: The incidence of chronic obstructive pulmonary disease (COPD) complicated with invasive pulmonary aspergillosis (IPA) has increased in the last two decades. The mechanism underpinning susceptibility to and high mortality of COPD complicated with IPA is unclear, and the role of T helper cells 17 (Th17 cells) in the compound disease remains unknown. Therefore, this study aimed to assess the function of Th17 cells in COPD combined with IPA. METHODS: COPD, IPA, and COPD+IPA mouse models were established in male wild type C57/BL6 mice. The amounts of Th17 cells and retinoic acid-related orphan receptors γt (RORγt) were tested by flow cytometry. Then, serum interleukin (IL)-17 and IL-23 levels were detected by enzyme-linked immunosorbent assay (ELISA) in the control, COPD, IPA and COPD+IPA groups. In addition, COPD+IPA was induced in IL-17 knockout (KO) mice, for determining the role of Th17 cells in COPD+IPA. RESULTS: Compared with the COPD group, the COPD+IPA group showed higher amounts of blood RORγt ([35.09 ±â€Š16.12]% vs. [17.92 ±â€Š4.91]%, P = 0.02) and serum IL-17 (17.96 ±â€Š9.59 pg/mL vs. 8.05 ±â€Š4.44 pg/mL, P = 0.02), but blood ([5.18 ±â€Š1.09]% vs. [4.15 ±â€Š0.87]%, P = 0.28) and lung levels of Th17 cells ([1.98 ±â€Š0.83]% vs. [2.03 ±â€Š0.98]%, P = 0.91), lung levels of RORγt ([9.58 ±â€Š6.93]% vs. [9.63 ±â€Š5.98]%, P = 0.49) and serum IL-23 (51.55 ±â€Š27.82 pg/mL vs. 68.70 ±â€Š15.20 pg/mL, P = 0.15) showed no significant differences. Compared with the IPA group, the COPD+IPA group displayed lower amounts of blood ([5.18 ±â€Š1.09]% vs. [9.21 ±â€Š3.56]%, P = 0.01) and lung Th17 cells ([1.98 ±â€Š0.83]% vs. [6.29 ±â€Š1.11]%, P = 0.01) and serum IL-23 (51.55 ±â€Š27.82 pg/mL vs. 154.90 ±â€Š64.60 pg/mL, P = 0.01) and IL-17 (17.96 ±â€Š9.59 pg/mL vs. 39.81 ±â€Š22.37 pg/mL, P = 0.02), while comparable blood ([35.09 ±â€Š16.12]% vs. [29.86 ±â€Š15.42]%, P = 0.25) and lung levels of RORγt ([9.58 ±â€Š6.93]% vs. [15.10 ±â€Š2.95]%, P = 0.18) were found in these two groups. Finally, Aspergillus load in IL-17 KO COPD+IPA mice was almost 2 times that of COPD+IPA mice (1,851,687.69 ±â€Š944,480.43 vs. 892,958.10 ±â€Š686,808.80, t = 2.32, P = 0.02). CONCLUSION: These findings indicate that Th17 cells might be involved in the pathogenesis of COPD combined with IPA, with IL-17 likely playing an antifungal role.

Chitosan regulates metabolic balance, polyamine accumulation, and Na+ transport contributing to salt tolerance in creeping bentgrass.

BACKGROUND: Chitosan (CTS), a natural polysaccharide, exhibits multiple functions of stress adaptation regulation in plants. However, effects and mechanism of CTS on alleviating salt stress damage are still not fully understood. Objectives of this study were to investigate the function of CTS on improving salt tolerance associated with metabolic balance, polyamine (PAs) accumulation, and Na+ transport in creeping bentgrass (Agrostis stolonifera). RESULTS: CTS pretreatment significantly alleviated declines in relative water content, photosynthesis, photochemical efficiency, and water use efficiency in leaves under salt stress. Exogenous CTS increased endogenous PAs accumulation, antioxidant enzyme (SOD, POD, and CAT) activities, and sucrose accumulation and metabolism through the activation of sucrose synthase and pyruvate kinase activities, and inhibition of invertase activity. The CTS also improved total amino acids, glutamic acid, and γ-aminobutyric acid (GABA) accumulation. In addition, CTS-pretreated plants exhibited significantly higher Na+ content in roots and lower Na+ accumulation in leaves then untreated plants in response to salt stress. However, CTS had no significant effects on K+/Na+ ratio. Importantly, CTS enhanced salt overly sensitive (SOS) pathways and also up-regulated the expression of AsHKT1 and genes (AsNHX4, AsNHX5, and AsNHX6) encoding Na+/H+ exchangers under salt stress. CONCLUSIONS: The application of CTS increased antioxidant enzyme activities, thereby reducing oxidative damage to roots and leaves. CTS-induced increases in sucrose and GABA accumulation and metabolism played important roles in osmotic adjustment and energy metabolism during salt stress. The CTS also enhanced SOS pathway associated with Na+ excretion from cytosol into rhizosphere, increased AsHKT1 expression inhibiting Na+ transport to the photosynthetic tissues, and also up-regulated the expression of AsNHX4, AsNHX5, and AsNHX6 promoting the capacity of Na+ compartmentalization in roots and leaves under salt stress. In addition, CTS-induced PAs accumulation could be an important regulatory mechanism contributing to enhanced salt tolerance. These findings reveal new functions of CTS on regulating Na+ transport, enhancing sugars and amino acids metabolism for osmotic adjustment and energy supply, and increasing PAs accumulation when creeping bentgrass responds to salt stress.

Application of alveolar recruitment strategy and positive end-expiratory pressure combined with autoflow in the one-lung ventilation during thoracic surgery in obese patients.

BACKGROUND: The present study aims to evaluate the influence of alveolar recruitment strategy (ARS) and positive end-expiratory pressure (PEEP) combined with autoflow on respiratory mechanics, the oxygen index (OI), pulmonary shut [Qs/Qt(%)], and the concentrations of IL-6 and TNF-α in venous blood after surgery in obese patients who experienced thoracic surgery with one-lung ventilation (OLV). METHODS: A total of 36 obese patients with ASAII-III degree, who experienced selective pulmonary lobectomy, were within 36-74 years old, and had a BMI of 30-40 kg/m2, were randomly divided into two groups: control group (C group) and protective ventilation group (P group). In the P group, ARS was given once when OLV began. Then, ventilation at 7 mmHg of PEEP and autoflow were given. The Ppeak before OLV (T1), at 30 minutes after OLV (T2), and at the 5 minutes after two-lung ventilation (TLV) (T3), and the changes of Pplat and Cdyn were recorded. Then, arteriovenous blood was drawn at T1, T2, T3 and T4 (6 hours after the operation), blood-gas indicators, including SPO2, PaCO2 and PaO2, were measured, and the value of Qs/Qt(%) was calculated. Afterwards, venous blood was collected at T1 and T5 (18 hours after surgery), and the concentrations of IL-6 and TNF-α were detected. The clinical pulmonary infection score (CPIS) was determined at the first day and seventh day after the operation. RESULTS: In both groups, Cdyn and OI decreased, while Pplat, Ppeak and Qs/Qt(%) increased (P<0.05) at T2, when compared with those at T1. At T2 and T3, Pplat and Ppeak decreased (P<0.05) in the P group, when compared with the C group. At T2, T3 and T4, OI increased (P<0.05) in the P group, when compared with the C group. At T2, T3 and T4, PaCO2 and Qs/Qt(%) decreased in the P group, when compared with the C group. The concentrations of IL-6 and TNF-α decreased in the P group, when compared with the C group. CONCLUSIONS: The ventilation model of ARS and PEEP combined with autoflow can better reduce airway pressure and the production of injurious inflammatory cytokines in blood in obese patients. Furthermore, it can reduce Qs/Qt during and at 6 hours after thoracotomy, improve OI and maintain the acid-base balance of the internal environment, which may be applied in clinical work. This brings new enlightenment and needs to be clarified through further studies.

[A comparison of double-lumen endotracheal tube with univent blocker and bronchial blocker during thoracic surgical anesthesia].

OBJECTIVE: To compare the effectiveness of lung isolation among double-lumen endotracheal tube, Univent blocker and bronchial blocker during thoracic surgical anesthesia. METHODS: A total of 120 patients undergoing elective thoracic surgery were enrolled. They were intubated with Mallinckrodt DLT (DLT group, n = 40), Univent blocker (UNI group, n = 40) and Coopdech bronchial blocker (BB group, n = 40) after intravenous anesthesia induction. The following parameters were recorded:(1) time to initially position the assigned tube; (2) changes of mean arterial pressure (MAP) and heart rate (HR) at 5 min post-intubation; (3) lung collapse scores; (4) frequency of malpositions; (5) airway press and blood gas change during one lung ventilation (OLV); (6)postoperative sore throat at 24 h postoperation. RESULTS: No statistical difference existed in positioning three types of endotracheal tubes. But MAP and HR were higher at post-intubation in DLT group compared with the other 2 groups. No difference existed among the lung isolation devices in lung collapse scores at 5/10 min after pleural opening. As compared with the UNI and BB groups, Ppeak and Pplat increased while compliance decreased in DLT group during OLV. Statistical differences existed in tube malpositions among three groups (n = 4, DLT; n = 5, UNI; n = 8, BB). The incidence of postoperative sore throat was significantly higher in DLT group (70%) than the other two groups (37.5%, UNI; 22.5%, BB). CONCLUSION: As compared with DLT, Univent and Coopdech bronchial blocker may reduce the airway injury and improve the compliance during OLV. But there is a higher intraoperative incidence of tube malposition.

Herbarone, a rearranged heptaketide derivative from the sea hare associated fungus Torula herbarum.

Herbarone (1), a novel heptaketide with a tetrahydro-5,9-methanobenzo[8]annulen-10(5H)-one skeleton, together with the new ent-astropaquinones B (2) and C (3) and four known pyranonaphthoquinones (4-7), was isolated from the sea hare associated fungus Torula herbarum. The structures of the new compounds were elucidated by detailed spectroscopic analysis, and the absolute configurations were determined by solution TDDFT/ECD calculations. Absolute configurations of the known compounds were studied by ECD measurements and calculations. The isolation of heptaketide 1 suggests that an intramolecular aldol reaction takes place to form the tricyclic scaffold.

[The diagnosis and therapy of chylous ascites].

OBJECTIVE: To discuss the diagnosis and therapy of chylous ascites. METHODS: To diagnose 40 patients of chylous ascite with regular test and quantitative analysis of chyle, direct lymphangiography, CT (immediately after direct lymphangiography), lymphangioscintigraphy, MRI. Twenty-two patients received conservative therapy, 18 patients received retroperitoneal lymphangiectomy and (or) lymph-vein shunting. RESULTS: Lymphatic dysplasia and chylous reflux were found in almost every patient, total parenteral nutrition showed good results. Followed up from 1 month to 5 years, in conservative therapy group, 9 patients were controlled well clinically, the condition of 6 patients was improved better. Seven patients showed no effect. In operation group, 11 patients were controlled well clinically. Four patients got mitigated. Total 7 patients died, although 4 of them ameliorated temporarily. CONCLUSIONS: Direct lymphangiography, CT (immediately after direct lymphangiography) are the most important diagnosis methods. The influence of the therapy to the malformed lymphatic system of patients should be well considered. Lymph-vein shunting, such as thoracic duct-left external jugular vein anastomosis, gastroenteral or retroperitoneal lymphatics-testicular or ovarian vein anastomosis, could improve the circulation of lymph and chyle of patients. Lymphatic microsurgery will play more and more important roles in the treatment of chylous diseases.