Direct Observation of Oxygen Atoms Taking Tetrahedral Interstitial Sites in Medium-Entropy Body-Centered-Cubic Solutions.

Interstitial solutes, such as carbon in steels, are effective solid-solution hardening agents. These alloying elements are believed to occupy the octahedral interstices in body-centered-cubic (bcc) metals. Using deep-sub-angstrom-resolution electron ptychography, here the first experimental evidence to directly observe individual oxygen atoms in a highly concentrated bcc solid solution-the (TiNbZr)86 O12 C1 N1 medium-entropy alloy (MEA)-is provided, whereby the interstitial sites in which the oxygen atoms are located are discerned. In addition to oxygen interstitials residing in octahedral sites, the first unambiguous evidence of a switch in preference to the unusual tetrahedral sites at high oxygen concentrations is shown. This shift away from octahedral occupancy is explained as resulting from the extra cost of strain energy when the requisite displacement of the host atoms is deterred in the presence of nearby octahedral interstitials.

Caffeic Acid Phenethyl Ester Inhibits Ubiquitination and Degradation of p53 and Blocks Cervical Cancer Cell Growth.

BACKGROUND: In high-risk human papillomavirus (HR-HPV)-positive cervical cancer, E6-associated protein (E6AP), an E3 ubiquitin ligase, mediates the ubiquitination and proteasomal degradation of the tumor suppressor p53. Here, we addressed the question of whether caffeic acid phenethyl ester (CAPE), a natural product mainly derived from propolis, can disrupt the interaction between E6AP and p53, inhibit ubiquitination degradation of p53 and exhibit anti-cervical cancer activity. METHODS: The ability of CAPE to inhibit growth and to induce apoptosis was shown in HR-HPV-positive cervical cancer cell lines by performing CCK-8, colony formation and TUNEL assays. Apoptosis-related proteins were tested by western blotting. Coimmunoprecipitation, ubiquitination assay and protein stability assay were carried out to determine whether CAPE can disrupt the E6AP-p53 interaction and inhibit ubiquitination degradation of p53. RESULTS: Our results showed that CAPE inhibits the growth of HR-HPV-positive cervical cancer cells and induces the activation of apoptosis-related pathways. Importantly, CAPE inhibits E6AP expression and disrupts the interaction between E6AP and p53. It inhibits the ubiquitination of p53 and promotes its stabilization. CONCLUSION: In summary, CAPE has a therapeutic effect on HPV-positive malignant cells, so further studies are needed to assess its clinical application.

Nematic-type Structure of the SnO2 (110) Surface at Room Temperature.

The most exposed (110) surface of SnO2 plays an important role in practical applications like gas sensors and catalysts. It has previously been considered to be amorphous at room temperature. In this study, the structure of the (110) surface stabilized at room temperature is determined using aberration-corrected transmission electron microscopy and first-principles calculations. The (110) surface has local order and is made of Sn2 O2 strands that partially cover underlying unsaturated Sn rows. The results indicate that the Sn2 O2 strands assemble as building blocks on the surface to form a partially ordered structure, quite like the nematic liquid crystal. Partial occupation of the Sn2 O2 strands along the [ 1 1 ‾ ${1\bar{1}}$ 0] direction avoids the interaction between neighboring Sn2 O2 strands and therefore makes the surface more stable. The novel phenomenon of the surface provides insight for understanding and developing catalysts and gas sensors based on SnO2 .

IL-6 gene rs1800795 polymorphism and diabetes mellitus: a comprehensive analysis involving 42,150 participants from a meta-analysis.

BACKGROUND: Over the past two decades, several studies have focused on the association between a common polymorphism (rs1800795) from interleukin-6 (IL-6) gene and Diabetes Mellitus (DM) risk. However, the results remain ambiguous and indefinite. METHODS: A comprehensive analysis was performed to explore this relationship. A search was conducted in the PubMed, Embase, Chinese (CNKI and Wanfang), and GWAS Catalog databases, covering all publications until February 10, 2022. Odds ratios (OR) with 95% confidence intervals (CI) were used to evaluate the strength of the association. Publication bias was assessed using both Begg and Egger tests. RESULTS: Overall, 34 case-control studies with 7257 T2DM patients and 15,598 controls, and 12 case-control studies (10,264 T1DM patients and 9031 health controls) were included in the analysis. A significantly lower association was observed between the rs1800795 polymorphism and T2DM risk in Asians, mixed population, and hospital-based (HB) subgroups (C-allele vs. G-allele: OR = 0.76, 95% CI 0.58-0.99, P = 0.039 for Asians; CG vs. GG: OR = 0.74, 95% CI 0.58-0.94, P = 0.014 for mixed population; CC vs. GG: OR = 0.61, 95% CI 0.41-0.90, P = 0.014 for HB). However, increased associations were found from total, mixed population, and HB subgroups between rs1800795 polymorphism and T1DM susceptibility (CG vs. GG: OR = 1.32, 95% CI 1.01-1.74, P = 0.043 for total population, CC vs. GG: OR = 2.45, 95% CI 1.18-5.07, P = 0.016 for mixed individuals; C-allele vs. G-allele: OR = 1.29, 95% CI 1.07-1.56, P = 0.0009 for HB subgroup). CONCLUSIONS: In summary, there is definite evidence to confirm that IL-6 rs1800795 polymorphism is associated with susceptibility to decreased T2DM and increased T1DM.

A new species of Nidirana (Anura, Ranidae) from northern Guangxi, China.

A new species of music frog, Nidiranaguibeiensis sp. nov., is described from northern Guangxi, China. Based on two mtDNA fragments analyzed, phylogenetic trees reveal that N.guibeiensis sp. nov. is most closely related to N.leishanensis. However, the new species can be identified by conspicuous diagnostic morphological characteristics as well as bioacoustics. In contrast to the known Nidirana species, the advertisement calls of the new species can be divided into three types, calls with one, two, and three notes. In addition, the new species has nest construction behavior, which is inconsistent with N.leishanensis. Nidiranaguibeiensis sp. nov. occurs in paddy fields or still pools at 300-1300 m a.s.l.

A macro-nano-atomic-scale high-throughput approach for material research.

Understanding the properties of materials requires structural characterization over large areas and different scales to link microstructure with performance. Here, we demonstrate a single-beam high-throughput scanning electron microscope allowing the collection of both secondary electron and backscattered electron signals over large areas. Combined with machine learning, a high efficiency in material research is achieved, illustrated here by a multiscale investigation of carbides in a second-generation nickel-base single-crystal superalloy. The resulting terabyte-sized panoramic atlas data, combined with conventional electron microscopy, enable a simultaneous multiscale analysis of carbide evolution during creep regarding specific type, location, composition, size, shape, and relationship with the matrix, providing sample-scale quantitative statistical data and giving a precise insight into the effect of carbides in the superalloy in a way not previously possible.

Surface Structures of Mn3O4 and the Partition of Oxidation States of Mn.

The Mn(III) ions at Mn3O4 surface are hypothesized to contribute to catalytic activity in oxygen reduction reaction. However, the surface structure and stability of Mn3O4 are far less understood. Here, the atomic structures of the widespread (101) and (001) surfaces of Mn3O4 are determined by combining aberration-corrected transmission electron microscopy and DFT calculations. The surface stabilization mechanisms and the oxidation states of Mn are revealed and correlated to the catalytic activity of the surfaces. The results show that the (101) surface undergoes a subsurface reconstruction, forming a rock-salt-type surface layer. The Mn(III) ions are in the outermost layer of the (001) surface but in the subsurface of the (101) surface. The surface partition of the Mn(III) ions provides a microscopic understanding to the observed higher catalytic activity of the (001) surface relative to the (101) surface and would contribute to further development of novel catalysts based on Mn3O4.

Atomic-scale insights into quantum-order parameters in bismuth-doped iron garnet.

Bismuth and rare earth elements have been identified as effective substituent elements in the iron garnet structure, allowing an enhancement in magneto-optical response by several orders of magnitude in the visible and near-infrared region. Various mechanisms have been proposed to account for such enhancement, but testing of these ideas is hampered by a lack of suitable experimental data, where information is required not only regarding the lattice sites where substituent atoms are located but also how these atoms affect various order parameters. Here, we show for a Bi-substituted lutetium iron garnet how a suite of advanced electron microscopy techniques, combined with theoretical calculations, can be used to determine the interactions between a range of quantum-order parameters, including lattice, charge, spin, orbital, and crystal field splitting energy. In particular, we determine how the Bi distribution results in lattice distortions that are coupled with changes in electronic structure at certain lattice sites. These results reveal that these lattice distortions result in a decrease in the crystal-field splitting energies at Fe sites and in a lifted orbital degeneracy at octahedral sites, while the antiferromagnetic spin order remains preserved, thereby contributing to enhanced magneto-optical response in bismuth-substituted iron garnet. The combination of subangstrom imaging techniques and atomic-scale spectroscopy opens up possibilities for revealing insights into hidden coupling effects between multiple quantum-order parameters, thereby further guiding research and development for a wide range of complex functional materials.

Direct observation of chemical short-range order in a medium-entropy alloy.

Complex concentrated solutions of multiple principal elements are being widely investigated as high- or medium-entropy alloys (HEAs or MEAs)1-11, often assuming that these materials have the high configurational entropy of an ideal solution. However, enthalpic interactions among constituent elements are also expected at normal temperatures, resulting in various degrees of local chemical order12-22. Of the local chemical orders that can develop, chemical short-range order (CSRO) is arguably the most difficult to decipher and firm evidence of CSRO in these materials has been missing thus far16,22. Here we discover that, using an appropriate zone axis, micro/nanobeam diffraction, together with atomic-resolution imaging and chemical mapping via transmission electron microscopy, can explicitly reveal CSRO in a face-centred-cubic VCoNi concentrated solution. Our complementary suite of tools provides concrete information about the degree/extent of CSRO, atomic packing configuration and preferential occupancy of neighbouring lattice planes/sites by chemical species. Modelling of the CSRO order parameters and pair correlations over the nearest atomic shells indicates that the CSRO originates from the nearest-neighbour preference towards unlike (V-Co and V-Ni) pairs and avoidance of V-V pairs. Our findings offer a way of identifying CSRO in concentrated solution alloys. We also use atomic strain mapping to demonstrate the dislocation interactions enhanced by the CSROs, clarifying the effects of these CSROs on plasticity mechanisms and mechanical properties upon deformation.

Surface termination and stoichiometry of LaAlO3(001) surface studied by HRTEM.

As an important topic of condensed matter physics, metal oxide surfaces often exhibit exotic properties such as high catalytic activity, enhanced ferroelectricity and electronic phase transition, originating from the different local symmetry with respect to the bulk. As the structure determination of oxide surfaces presents challenges to conventional surface science techniques like scanning tunneling microscopy, aberration-corrected transmission electron microscopy (TEM) has been increasingly used to solve structures of oxide surfaces. In this work, the (001) surface of LaAlO3, one of the most used components of oxide heterostructures, has been investigated. Our TEM experiments and extensive image simulations show that the La-O terminated LaAlO3(001) surface undergoes significant reconstructions, forming La vacancies on the surface layer. Energetically, the LaAlO3(001) surface is stable with the reconstructed La-O termination in a wide range of oxygen chemical potentials. Polarity compensation, reduced density of states at the Fermi level and bond enhancement of subsurface oxygen anions all contribute to the stabilization of the reconstructed surface.

Effect of Oxygen Interstitial Ordering on Multiple Order Parameters in Rare Earth Ferrite.

Oxygen interstitials and vacancies play a key role in modulating the microstructure and properties of nonstoichiometric oxide systems, such as those used for superconductors and multiferroics. Key to understanding the tuning mechanisms resulting from oxygen doping is a knowledge of the precise positions of these lattice defects, and of the interaction both between these defects and with many order parameters. Here, we report how such information can, for the first time, be obtained from a sample of LuFe_{2}O_{4.22} using a range of techniques including advanced electron microscopy, atomic-resolution spectroscopy, and density functional theory calculations. The results provide quantitative atomic details of the crystal unit cell, together with a description of the ferroelastic, ferroelectric, and ferromagnetic order parameters. We elucidate also the interaction between these order parameters and the positions of the oxygen interstitials in the oxygen-enriched sample. The comprehensive analysis of oxygen interstitial ordering provides insights into understanding the coupling among different degrees of freedom in rare earth ferrites and demonstrates that oxygen content regulation is a powerful tool for tuning the microstructure and properties for this class of quantum material.

Subsurface reconstruction and saturation of surface bonds.

Surface reconstructions and stabilization mechanisms have been great challenges for insulators. Based on accurate determination of the long-sought atomic structure of the spinel (1 1 1) surface, here we show that the surface is stabilized by an unconventional mechanism. In general, solid surfaces have unsaturated chemical bonds and are prone to atomic reconstruction to saturate them. The spinel (1 1 1) surface, however, has the surface bonds fully saturated, while the unsaturated bonds remain only in the subsurface. It undergoes a reconstruction that keeps the topmost atomic layer unchanged, but has the subsurface atoms completely rearranged. Such a reconstruction results in a perfect compensation of the surface polarity and a large reduction in the surface energy. This work provides surprising insights into the surface stability and physical and chemical behaviors of complex oxides and insulators.

3D Quantification of Low-Coordinate Surface Atom Density: Bridging Catalytic Activity to Concave Facets of Nanocatalysts in Fuel Cells.

A protocol to quantify the distribution of surface atoms of concave nanocatalysts according to their coordination number is proposed. The 3D surface of an Au@Pd concave nanocube is reconstructed and segmented. The crystallographic coordinates and low-coordinate surface atom densities of the concave facets are determined. The result shows that 32% of the surface atoms are low-coordinated, which may contribute to the high activity.

Electrochemically Seed-Mediated Synthesis of Sub-10 nm Tetrahexahedral Pt Nanocrystals Supported on Graphene with Improved Catalytic Performance.

Controlling the surface structure of Pt nanocrystals (NCs), especially creating high-index facets with abundant active step sites, is an effective approach to enhance catalytic performances. However, the available high-index faceted Pt NCs have large particle sizes, which severely impedes their practical applications. In this study, we reported a new electrochemically seed-mediated method, by which sub-10 nm tetrahexahedral Pt NCs (THH Pt NCs) enclosed with {210} high-index facets supported on graphene were synthesized. Pt nanoparticles of ∼3 nm in size as high-density crystal seeds play a key role in the small-sized control. The obtained THH Pt NCs exhibited a higher mass activity than commercial Pt/C catalyst for ethanol electrooxidation. We further demonstrated that this method is also valid for reshaping commercial Pt/C, to create high-index facets on surfaces and thus to improve both mass activity and stability.

Determination of the incommensurate modulated structure of Bi(2)Sr(1.6)La(0.4)CuO(6+δ) by aberration-corrected transmission electron microscopy.

The incommensurate modulated structure (IMS) of Bi2Sr1.6La0.4CuO6+δ (BSLCO) has been studied by aberration-corrected transmission electron microscopy in combination with a high-dimensional (HD) space description. Two images are deconvoluted in the negative Cs imaging (NCSI) and positive Cs imaging (PCSI) modes. Similar results for the IMS have been obtained from two corresponding projected potential maps (PPMs), and the size of the dots representing atoms in the NCSI PPM is found to be smaller than that in the PCSI PPM. Considering that the object size is one of the factors that influence the precision of the structural determination, modulation functions for all unoverlapped atoms in BSLCO were determined on the basis of the NCSI PPM in combination with the HD space description.

Atomic structure and polarity compensation of BaTiO3 (1 1 1) surface.

Surfaces of perovskite-type oxides have been attracting increasing interest for their primary importance in various potential applications such as multiferroic thin films, interface electronics and catalysis. However, the (1 1 1) surface of BaTiO3, the most typical ferroelectric, is far from well understood. In this work, the atomic structure and polarity compensation of BaTiO3 (1 1 1) surface have been investigated combining aberration-corrected transmission electron microscopy and first-principle calculations. Depending on the density of oxygen vacancies, the surface shows different degrees of atomic relaxation and electronic charge transfer, which compensates the surface polarity together with the ionic charges associated with the oxygen vacancies. The atomic relaxation and charge transfer would have a direct impact on the ferroelectric and catalytic properties of low-dimensional BaTiO3.

Lattice Strain Distributions in Individual Dealloyed Pt-Fe Catalyst Nanoparticles.

Lattice strain is considered to play an important role in the oxygen reduction catalysis on Pt-based catalysts. However, so far, direct evidence of the lattice strain in the catalyst nanoparticles has not been achieved. By using aberration-corrected high-resolution transmission electron microscopy combined with image simulations, a unique core-shell structure, that is, a percolated lattice-contracted Pt-Fe alloy core and a Pt-rich surface with a gradient compressive strain, was directly demonstrated within individual dealloyed Pt-Fe nanoparticles and thus provides direct evidence for the strain effect on their enhanced oxygen reduction activity.

Undulating slip in Laves phase and implications for deformation in brittle materials.

By combining density-functional theory calculations and aberration-corrected transmission electron microscopy, dislocations in Laves phase (a typical complex intermetallic compound) are shown to slip in an undulating path. During the slip, the dislocation cores jump up and down between a weakly bound plane and an adjacent strongly bound plane for gliding and atomic shuffling, respectively. This is different from the conventional slip process in simple metals, which is continuous within a single plane, as described in the paradigm of the generalized stacking fault energy.

[The effect of specific immunotherapy on the regulation of Th1/Th2 cell ratio of the patients with allergic rhinitis in serum].

OBJECTIVE: To explore the effects of specific immunotherapy by the nasal spray and/or sublingual contain on the regulation the balance of serum Th1/Th2 cell ratio, and the expression of total IgE (tIgE) level in perennial allergic rhinitis patients. METHOD: Thirty-six cases of allergic rhinitis of perennial (PAR) patients with nasal specific immunotherapy (nasal spray group) were chosen as the object of study, 36 PAR patients with sublingual specific immunotherapy (sublingual group) were chosen for the efficacy comparison group, and 32 cases of healthy adults as control (normal control group). The levels of serum IL-2, IL-4, IL-8 and tIgE in PAR nasal spray group and sublingual group were examined by IRMA and double-antibody sandwich assay before and after the treatment of specific immunotherapy (SIT); The content of IFN-gamma was determined by enzyme-linked immunosorbent assay; The infiltration and changes of eosinophilic granulocyte were observed by the smear of nasal secretions. RESULT: In nasal spray group and sublingual group, the contents of serum Th1 cytokines IL-2 and IFN-gamma were reduced levels significantly, while the contents of Th2 cytokines IL-4, IL-8 and tIgE were significantly increased before the treatment of SIT. After the SIT to the maintenance dose, the levels of IL-2 and IFN-gamma in serum were significantly higher than that before treatment, while IL-4, IL-8 and tIgE content were significantly lower in AR patients (P < 0.01 or P < 0.05). The clinical efficacy of nasal spray group and sublingual group were 97.22% and 94.44%, while the two groups was no statistical difference in efficacy (P > 0.05). CONCLUSION: With the presence of Th1/Th2 cell ratio and cytokine imbalance, the AR patients manifested as Th2 cell function in accentuation. Nasal mucosa and/or sublingual in the local SIT can have changed no-balance Th1/Th2 cell of by regulating the balance of serum Th1/Th2 cell ratio, the expression level of cytokine expression and the level of tIgE.