Structure Responsible for the Superconducting State in La3Ni2O7 at High-Pressure and Low-Temperature Conditions.

Very recently, a new superconductor with Tc = 80 K has been reported in nickelate (La3Ni2O7) at around 15-40 GPa conditions (Nature, 621, 493, 2023), which is the second type of unconventional superconductor, besides cuprates, with Tc above liquid nitrogen temperature. However, the phase diagram plotted in this report was mostly based on the transport measurement under low-temperature and high-pressure conditions, and the assumed corresponding X-ray diffraction (XRD) results were carried out at room temperature. This encouraged us to carry out in situ high-pressure and low-temperature synchrotron XRD experiments to determine which phase is responsible for the high Tc state. In addition to the phase transition from the orthorhombic Amam structure to the orthorhombic Fmmm structure, a tetragonal phase with the space group of I4/mmm was discovered when the sample was compressed to around 19 GPa at 40 K where the superconductivity takes place in La3Ni2O7. The calculations based on this tetragonal structure reveal that the electronic states that approached the Fermi energy were mainly dominated by the eg orbitals (3dz2 and 3dx2-y2) of Ni atoms, which are located in the oxygen octahedral crystal field. The correlation between Tc and this structural evolution, especially Ni-O octahedra regularity and the in-plane Ni-O-Ni bonding angles, is analyzed. This work sheds new light to identify what is the most likely phase responsible for superconductivity in double-layered nickelate.

Antiferroelectricity-Induced Negative Thermal Expansion in Double Perovskite Pb2 CoMoO6.

Materials with negative thermal expansion (NTE) attract significant research attention owing to their unique physical properties and promising applications. Although ferroelectric phase transitions leading to NTE are widely investigated, information on antiferroelectricity-induced NTE remains limited. In this study, single-crystal and polycrystalline Pb2 CoMoO6 samples are prepared at high pressure and temperature conditions. The compound crystallizes into an antiferroelectric Pnma orthorhombic double perovskite structure at room temperature owing to the opposite displacements dominated by Pb2+ ions. With increasing temperature to 400 K, a structural phase transition to cubic Fm-3m paraelectric phase occurs, accompanied by a sharp volume contraction of 0.41%. This is the first report of an antiferroelectric-to-paraelectric transition-induced NTE in Pb2 CoMoO6 . Moreover, the compound also exhibits remarkable NTE with an average volumetric coefficient of thermal expansion αV = -1.33 × 10-5 K-1 in a wide temperature range of 30-420 K. The as-prepared Pb2 CoMoO6 thus serves as a prototype material system for studying antiferroelectricity-induced NTE.

In Situ Real-Time Observation of Formation and Self-Assembly of Perovskite Nanocrystals at High Temperature.

All-inorganic cesium lead halide perovskite nanocrystals (NCs) have received much attention due to their outstanding optical and electronic properties, but the underlying growth mechanism remains elusive due to their rapid formation process. Here, we report an in situ real-time study of the growth of Cs4PbBr6 NCs under practical synthesis conditions in a custom-made reactor. Through the synchrotron-based small-angle X-ray scattering technique, we find that the formation of Cs4PbBr6 NCs is accomplished in three steps: the fast nucleation process accompanied by self-focusing growth, the subsequent diffusion-limited Ostwald ripening, and the self-assembly of NCs into the face-centered cubic (fcc) superlattices at high temperature and the termination of growth. The simultaneously collected wide-angle X-ray scattering signals further corroborate the three-step growth model. The influence of superlattice formation is also elucidated, which improves the uniformity of the final NCs.

Development of a capillary electrophoresis method based on magnetic solid-phase extraction for simultaneous and sensitive detection of eight biogenic amines in foods.

BACKGROUND: Biogenic amines (BAs) in high concentrations are toxic and may cause a series of health symptoms. A sensitive measurement of BA levels is essential for human health. Capillary electrophoresis (CE) has emerged for the separation of eight BAs due to simple sample preparation and highly efficient separation. However, an important drawback for CE is low sensitivity. Magnetic solid-phase extraction (MSPE) has become a technique of interest owing to its brief operation and low solvent consumption. Hence, MSPE as a pretreatment has great potential to improve CE sensitivity for the analysis of BAs in complex food. RESULTS: Results showed that the Pt-Co-MWCNTs-COOH possessed strong magnetism, good reusability, and high adsorptive ability toward eight biogenic amines based on the hydrogen bonding between the -COOH of Pt-Co-MWCNTs-COOH and -NH2 groups of BAs. Using it as an adsorbent, a magnetic solid-phase extraction coupled with capillary electrophoresis (MSPE-CE) method was developed to effectively extract and sensitively analyze eight BAs. Under optimal conditions, the MSPE-CE method has wide linearities (10.0-1000.0 µg L-1 ) and low limits of detection (1.0-6.1 µg L-1 ). The accuracy of the developed method yielded recovery values from 82.07% to 102.58%. Meanwhile, the BAs contents in two samples were analyzed using the MSPE-CE method, with the results consistent with those detected by a high-performance liquid chromatography method. CONCLUSION: Given those advantages, the established MSPE-CE method promises the practical guidance of monitoring a variety of BAs and provides a foundation for the detection of other food hazards. © 2023 Society of Chemical Industry.

Cantharidin induces apoptosis of human triple negative breast cancer cells through mir-607-mediated downregulation of EGFR.

BACKGROUND: Triple negative breast cancer (TNBC) is a major subtype of breast cancer, with limited therapeutic drugs in clinical. Epidermal growth factor receptor (EGFR) is reported to be overexpressed in various TNBC cells. Cantharidin is an effective ingredient in many clinical traditional Chinese medicine preparations, such as Delisheng injection, Aidi injection, Disodium cantharidinate and vitamin B6 injection. Previous studies showed that cantharidin had satisfactory pharmacological activity on a variety of tumors. In this study, we aimed to study the therapeutic potential of cantharidin for TNBC treatment by targeting EGFR, and expound its novel regulator miR-607. METHODS: The effect of cantharidin on breast cancer in vivo was evaluated by 4T1 mice model. Then the effects of cantharidin on TNBC cells was assessed by the MTT, colony formation, and AnnexinV-PE/7AAD staining. Cantharidin acts on EGFR were verified using the cell membrane chromatography, RT-PCR, Western blotting, MTT, and so on. Mechanistic studies were explored by dual-luciferase report assay, RT-PCR, western blotting, and immunofluorescence staining assay. RESULTS: Cantharidin inhibited TNBC cell growth and induce apoptosis by targeting EGFR. miR-607 was a novel EGFR regulator and exhibited suppressive functions on TNBC cell behaviors. Mechanistic study showed that cantharidin blocked the downstream PI3K/AKT/mTOR and ERK/MAPK signaling pathway. CONCLUSION: Our results revealed that cantharidin may be served as a potential candidate for TNBC treatment by miR-607-mediated downregulation of EGFR.

Chemical pressure in functional materials.

Chemical pressure, a strange but familiar concept, is a lattice internal force caused by lattice strain with chemical modifications and arouses great interest due to its diversity and efficiency to synthesize new compounds and tune functional materials. Different from physical pressure loaded by an external force that is positive, chemical pressure can be either positive or negative (contract a lattice or expand it), often through flexible and mild chemical synthesis strategies, which are particularly important as a degree of freedom to manipulate material behaviors. In this tutorial review, we summarize the features of chemical pressure as a methodology and demonstrate its role in synthesizing and discovering some typical magnetically, electrically, and thermally responsive functional materials. The measure of chemical pressure using experimental lattice strain and elastic modulus was proposed, which can be used for quantitative descriptions of the correlation between lattice distortion and properties. From a lattice strain point of view, we classify chemical pressure into different categories: (i) chemical substitution, (ii) chemical intercalation/de-intercalation, (iii) size effect, and (iv) interface constraint, etc. Chemical pressure affects chemical bonding and rationalizes the crystal structure by modifying the electronic structure of solids, regulating the lattice symmetry, local structure, phonon structure effects etc., emerging as a general and effective method for synthesizing new compounds and tuning functional materials.

Negative Design Margin Realization through Deep Path Activity Detection Combined with Dynamic Voltage Scaling in a 55 nm Near-Threshold 32-Bit Microcontroller.

This paper presents an innovative approach for predicting timing errors tailored to near-/sub-threshold operations, addressing the energy-efficient requirements of digital circuits in applications, such as IoT devices and wearables. The method involves assessing deep path activity within an adjustable window prior to the root clock's rising edge. By dynamically adapting the prediction window and supply voltage based on error detection outcomes, the approach effectively mitigates false predictions-an essential concern in low-voltage prediction techniques. The efficacy of this strategy is demonstrated through its implementation in a near-/sub-threshold 32-bit microprocessor system. The approach incurs only a modest 6.84% area overhead attributed to well-engineered lightweight design methodologies. Furthermore, with the integration of clock gating, the system functions seamlessly across a voltage range of 0.4 V-1.2 V (5-100 MHz), effectively catering to adaptive energy efficiency. Empirical results highlight the potential of the proposed strategy, achieving a significant 46.95% energy reduction at the Minimum Energy Point (MEP, 15 MHz) compared to signoff margins. Additionally, a 19.75% energy decrease is observed compared to the zero-margin operation, demonstrating successful realization of negative margins.

In Situ Observing and Tuning the Crystal Orientation of Two-Dimensional Layered Perovskite via the Chlorine Additive.

Precise control of crystal orientation in two-dimensional (2D) layered perovskites (LPs) is vital for their optoelectronic applications due to the structure-induced anisotropy in optical and electrical properties. Herein, we directly observe and control the crystal orientation of the butylammonium-based 2D LP films. Employing the synchrotron-based in situ grazing-incidence X-ray diffraction technique, we reveal the orientation modulation mechanism of the Cl additive by following the crystallization dynamics and chemical conversion pathways during film formation. Two new Cl-related intermediates are identified which serve as templates directing the orientational growth of the 2D LP films. We fine-tune the crystal orientation of 2D LP films through the Cl additive and incorporate the films with the requisite crystal orientations in solar cells and photodetectors. The optoelectronic performances of the devices show a strong correlation with the crystal orientation of the 2D LP films.

Noncovalent Self-Assembly of Protein Crystals with Tunable Structures.

Engineering noncovalent interactions for assembling nonspherical proteins into supramolecular architectures with tunable morphologies and dynamics is challenging due to the structural heterogeneity and complexity of protein surfaces. Herein, we employed an anisotropic building block l-rhamnulose-1-phosphate aldolase (RhuA) to control supramolecular polymorphism in highly ordered protein assemblies by introducing histidine residues. Histidine-based π-π stacking interactions enabled thermodynamically controlled self-organization of RhuA to form three-dimensional (3D) nanoribbons and crystals. Self-assembly of different 3D crystal phases was kinetically modulated by the strong metal ion-histidine chelation, and double-helical protein superstructures were formed by engineering increased histidine interactions at the RhuA binding surface. Their structural properties and dynamics were determined via fluorescence microscopy, transmission electron microscopy, atomic force microscopy, and small-angle X-ray scattering. This work is aimed at expanding the toolbox for the programming of tunable, highly ordered, protein superstructures and increasing the understanding of the mechanisms of protein interfacial interactions.

A Capillary Electrophoresis Method Based on Molecularly Imprinted Solid-Phase Extraction for Selective and Sensitive Detection of Histamine in Foods.

In this study, a sensitive capillary electrophoresis (CE) method based on molecularly imprinted solid-phase extraction (MISPE) was proposed to determine histamine in foods. A molecularly imprinted polymer (MIP) synthesized by bulk polymerization was used as the MISPE adsorbent for the selective extraction of histamine. Under the optimal conditions, the MISPE-CE method possessed good linearity for histamine detection in the concentration range of 0.1-100.0 µg/L. The limit of detection and limit of quantification of the method were calculated to be 0.087 µg/L and 0.29 µg/L, respectively. The histamine in spiked rice vinegar and liquor samples were detected by the developed method with recoveries of 92.63-111.00%. The histamine contents in fish, prawn, pork, chicken breast and soy sauce samples were determined using the developed method and a high-performance liquid chromatography method, with no significant difference found between the two methods.

Humidity-Induced Defect-Healing of Formamidinium-Based Perovskite Films.

Formamidinium (FA)-based perovskite material holds great potential to deliver highly efficient commercial solar cells. However, the FA-based perovskite films are commonly processed under a strictly controlled environment, which would eventually hinder their way to commercialization. Herein, a systematic study is conducted to investigate the sequential deposition of FA-based perovskite films that are annealed under ambient conditions. Unexpectedly, the films prepared in low humidity condition possess less pinholes and defects and exhibit better device performances than those prepared in the moisture-free condition. A series of in situ and ex situ investigations are conducted which reveal defects in perovskite films are continuously healed during the film annealing process under the humid condition. This extraordinary effect is attributed to the interaction between water molecules and perovskite. The current study should shed light on the ambient fabrication of FA-based perovskite solar cells and foster their real-world applications.

TPD7 inhibits the growth of cutaneous T cell lymphoma H9 cell through regulating IL-2R signalling pathway.

IL-2R pathway is a key regulator in the development of immune cells and has emerged as a promising drug target in cancer treatment, but there is a scarcity of related inhibitors. TPD7 is a novel biphenyl urea taspine derivate, which has been shown anti-cancer effect. Here, we demonstrated the anti-cancer activity of TPD7 in cutaneous T cell lymphoma and investigated the underlying mechanism of TPD7 through IL-2R signalling. The inhibitory effect of TPD7 on cell viability exhibited a strong correlation with the expression level of IL-2R, and cutaneous T cell lymphoma H9 and HUT78 cells were most sensitive to TPD7. TPD7 was nicely bound to IL-2R and down-regulated the mRNA and protein levels of IL-2R. Furthermore, TPD7 suppressed the downstream cascades of IL-2R including JAK/STAT, PI3K/AKT/mTOR and PLCγ/Raf/MAPK signalling, resulting in Bcl-2 mitochondrial apoptosis pathway and cell cycle proteins CDK/Cyclins regulation. And, these were verified by flow cytometry analysis that TPD7 facilitated cell apoptosis in H9 cells via mitochondrial pathway and impeded cell cycle progression at G2/M phase. TPD7 is a novel anti-cancer agent and may be a potential candidate for cutaneous T cell lymphoma treatment by regulating IL-2R signalling pathway.

SNHG1/miR-556-5p/TCF12 feedback loop enhances the tumorigenesis of meningioma through Wnt signaling pathway.

Meningioma, as a sort of the malignantly intracranial tumors, has captured public attention for its second-highest morbidity all over the world. Long noncoding RNAs (lncRNAs), including lncRNA SNHG1, have been well known as essential players in the development of diverse cancers. However, the biological effect and regulatory mechanism of SNHG1 have not been mentioned in meningioma. In this work, it was discovered that SNHG1 was overexpressed in meningioma cell lines. SNHG1 deficiency restrained cell growth as well as accelerated apoptosis. Then mechanism experiments demonstrated that SNHG1 functioned as the role of sponging miR-556-5p and negatively regulated miR-556-5p expression. Moreover, it was verified that TCF12 is the direct downstream target of miR-556-5p. Furthermore, SNHG1/miR-556-5p/TCF12 axis promoted cell proliferation and suppressed cell apoptosis in meningioma via activating the Wnt signaling pathway. In the end, it was confirmed that TCF12 expression was positively regulated by SNHG1, and TCF12 could promote transcription of SNHG1 through binding with the promoter region of SNHG1. In conclusion, the SNHG1/miR-556-5p/TCF12 feedback loop promotes the tumorigenesis of meningioma through the Wnt signaling pathway.

Cantharidin treatment inhibits hepatocellular carcinoma development by regulating the JAK2/STAT3 and PI3K/Akt pathways in an EphB4-dependent manner.

Hepatocellular carcinoma (HCC) is a lethal malignancy with limited treatment options. The tyrosine kinase receptor EphB4 promotes oncogenesis and tumor development and progression. Its inhibition is regarded as an effective strategy for the treatment of solid tumors. In the present study, we identified cantharidin as a novel EphB4 inhibitor for HCC treatment and evaluated the underlying molecular pharmacological mechanisms of action. We observed increased expression levels of EphB4 in HCC patients and a positive correlation between EphB4 and p-JAK2 levels in HCC patient samples. Knockdown of EphB4 using small interfering RNA decreased the expression levels of p-JAK2 and p-STAT3 in HCC cells, suggesting JAK2/STAT3 being a novel downstream signaling target of EphB4. Cell viability experiments revealed that the anti-cancer effect of cantharidin was positively correlated with EphB4 expression levels in HCC cell lines. We confirmed the potent antiproliferative activity of cantharidin on HepG2 cells with high expression of EphB4 and tumor xenograft. Molecular docking assay, immunoblotting assay and quantitative reverse transcription PCR assay indicated that cantharidin bound to EphB4, and thereby resulted in EphB4 suppression at mRNA and protein levels. Hep3B and SMMC-7721 cells were with low expression of EphB4. In EphB4-/HepG2, EphB4+/HepG2, and EphB4+/Hep3B cells, EphB4 knockdown alleviated the cantharidin-induced decrease in cell viability and colony formation ability and increase in apoptosis in HepG2 cells, while its overexpression exacerbated these effects in Hep3B cells and increased the apoptosis of HepG2 cells. In nude mouse models, cantharidin suppressed tumor growth more effectively in EphB4+/SMMC-7721 xenografts than in wild-type SMMC-7721 xenografts. Underlying mechanistic study showed that by targeting EphB4, cantharidin blocked a novel target, the downstream JAK2/STAT3 pathway, and the previously known target, the PI3K/Akt signaling, resulting in intrinsic apoptosis. These results indicated that cantharidin may be a potential candidate for HCC treatment by regulating the EphB4 signaling pathway.

Synergistic effect of berberine and HMQ1611 impairs cell proliferation and migration by regulating Wnt signaling pathway in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a biologically complex disease. Combination chemotherapy is a good strategy after surgery treatment. In this study, we report that berberine combined with HMQ1611 (BCH) had a good synergistic effect on the HCC. Our findings concluded that BCH showed good inhibition on the HCC proliferation and colony formation, which attributed to cell cycle arrest by BCH at G1 phase through impairing the expression of cyclinD1, cyclinE, and cdc2 and downregulated the phosphorylation of Akt, mTOR, and ERK. Moreover, BCH negatively regulated Wnt signaling pathway by upregulating the Axin and inhibiting the nuclear translocation of ß-catenin. BCH suppressed the phosphorylation of LRP5/6, GSK3ß, the expression of Wnt5a, Frizzled8, CK1, and APC, as well as the nucleus protein included MMP2, MMP3, MMP9, and c-myc. The above data of Wnt signaling regulators contributed to inhibition by BCH on cell migration. In vivo studies, BCH significantly suppressed the growth of SMMC-7721 xenograft tumors through downregulating Ki67 and ß-catenin, as well as upregulating Axin and p-ß-catenin. In conclusion, the results revealed that BCH exhibited potential antitumor activities against human liver cancer in vitro and in vivo, and the potential mechanism underlying these activities depended on the inhibition of the Wnt/ß-catenin signaling pathway.

Colossal Volume Contraction in Strong Polar Perovskites of Pb(Ti,V)O3.

The unique physical property of negative thermal expansion (NTE) is not only interesting for scientific research but also important for practical applications. Chemical modification generally tends to weaken NTE. It remains a challenge to obtain enhanced NTE from currently available materials. Herein, we successfully achieve enhanced NTE in Pb(Ti1-xVx)O3 by improving its ferroelectricity. With the chemical substitution of vanadium, lattice tetragonality (c/a) is highly promoted, which is attributed to strong spontaneous polarization, evidenced by the enhanced covalent interaction in the V/Ti-O and Pb-O2 bonds from first-principles calculations. As a consequence, Pb(Ti0.9V0.1)O3 exhibits a nonlinear and much stronger NTE over a wide temperature range with a volumetric coefficient of thermal expansion αV = -3.76 × 10-5/°C (25-550 °C). Interestingly, an intrinsic giant volume contraction (∼3.7%) was obtained at the composition of Pb(Ti0.7V0.3)O3 during the ferroelectric-to-paraelectric phase transition, which represents the highest value ever reported. Such volume contraction is well correlated to the effect of spontaneous volume ferroelectrostriction. The present study extends the scope of the NTE family and provides an effective approach to explore new materials with large NTE, such as through adjusting the NTE-related ferroelectric property in the family of ferroelectrics.

A-Site and B-Site Charge Orderings in an s-d Level Controlled Perovskite Oxide PbCoO3.

Perovskite PbCoO3 synthesized at 12 GPa was found to have an unusual charge distribution of Pb2+Pb4+3Co2+2Co3+2O12 with charge orderings in both the A and B sites of perovskite ABO3. Comprehensive studies using density functional theory (DFT) calculation, electron diffraction (ED), synchrotron X-ray diffraction (SXRD), neutron powder diffraction (NPD), hard X-ray photoemission spectroscopy (HAXPES), soft X-ray absorption spectroscopy (XAS), and measurements of specific heat as well as magnetic and electrical properties provide evidence of lead ion and cobalt ion charge ordering leading to Pb2+Pb4+3Co2+2Co3+2O12 quadruple perovskite structure. It is shown that the average valence distribution of Pb3.5+Co2.5+O3 between Pb3+Cr3+O3 and Pb4+Ni2+O3 can be stabilized by tuning the energy levels of Pb 6s and transition metal 3d orbitals.

High-Pressure Synthesis of the Cobalt Pyrochlore Oxide Pb2Co2O7 with Large Cation Mixed Occupancy.

The novel A2B2O7-type compound Pb2Co2O7 was synthesized at 8 GPa and 1673 K. Synchrotron X-ray diffraction shows a cubic pyrochlore structure with space group Fd3̅m. Rietveld structural analysis reveals a large cation mixed occupancy at both A and B sites by about 40%, the greatest value found in the pyrochlore family. In combination with the X-ray absorption spectroscopy results, the specific chemical composition and charge states are determined to be (Co0.6Pb0.4)3+2(Pb0.6Co0.4)4+2O7, in which both the A-site Co3+ and the B-site Co4+ are low-spin. Due to the tetrahedral geometric frustration effects as well as the random Co4+ and Pb4+ distribution at the B site, spin glassy behavior is well observed following the conventional critical slowing down feature in Pb2Co2O7.

High-Temperature Monoclinic Cc Phase with Reduced c/a Ratio in Bi-based Perovskite Compound Bi2ZnTi1-xMnxO6.

Monoclinic phases with Cm, Pm, and Cc space groups are indispensable to understand the high performance of electromechanical properties at the morphotropic phase boundary (MPB) of lead-based perovskite oxides Pb(ZrxTi1-x)O3 (PZT), [Pb(Mg1/3Nb2/3)O3]1-x-(PbTiO3)x (PMN-PT), and [Pb(Zn1/3Nb2/3)O3]1-x-(PbTiO3)x (PZN-PT). Here, a nearly single monoclinic phase with space group Cc was observed in the Bi-based lead-free perovskite compound Bi2ZnTi1-xMnxO6 at x = 0.4. This phase was the same as the low-temperature phase of the MPB composition of PZT but existed at a much higher temperature. Despite the reduced pseudo c/a ratio of 1.065, which is the same as that of PbTiO3 at room temperature, ionic model calculation based on the Rietveld refinement data indicated the polarization of Bi2ZnTi0.6Mn0.4O6 is 95.8 µC/cm(2). The tilting and significant anisotropic distortion of the octahedron were found to cause the c/a ratio to reduce. Accordingly, the effective piezoelectric constant d33 of Bi2ZnTi0.6Mn0.4O6 thin film was found to be 12 pm/V.

Giant Polarization and High Temperature Monoclinic Phase in a Lead-Free Perovskite of Bi(Zn0.5Ti0.5)O3-BiFeO3.

Lead-free piezoelectrics have attracted increasing attention because of the awareness of lead toxicity to the environment. Here, a new bismuth-based lead-free perovskite, (1 - x)Bi(Zn0.5Ti0.5)O3-xBiFeO3, has been synthesized via a high-pressure and high-temperature method. It exhibits interesting properties of giant polarization, morphotropic phase boundary (MPB), and monoclinic phase. In particular, large tetragonality (c/a = 1.228) and giant spontaneous polarization of 110 µC/cm2 has been obtained in 0.6 Bi(Zn0.5Ti0.5)O3-0.4BiFeO3, which is much higher than most available lead-free materials and conventional Pb(Zr,Ti)O3. MPB is clearly identified to be constituted of tetragonal and monoclinic phases at x = 0.5. Notably, a single monoclinic phase has been observed at x = 0.6, which exhibits an intriguing high-temperature property. The present results are helpful to explore new lead-free MPB systems in bismuth-based compounds.