Magic-angle helical trilayer graphene.

We propose magic-angle helical trilayer graphene (HTG), a helical structure featuring identical rotation angles between three consecutive layers of graphene, as a unique and experimentally accessible platform for realizing exotic correlated topological states of matter. While nominally forming a supermoiré (or moiré-of-moiré) structure, we show that HTG locally relaxes into large regions of a periodic single-moiré structure realizing flat topological bands carrying nontrivial valley Chern number. These bands feature near-ideal quantum geometry and are isolated from remote bands by a very large energy gap, making HTG a promising platform for experimental realization of correlated topological states such as integer and fractional quantum anomalous Hall states.

Electrical switching of a bistable moiré superconductor.

Electrical control of superconductivity is critical for nanoscale superconducting circuits including cryogenic memory elements, superconducting field-effect transistors (FETs) and gate-tunable qubits. Superconducting FETs operate through continuous tuning of carrier density, but no bistable superconducting FET, which could serve as a new type of cryogenic memory element, has been reported. Recently, gate hysteresis and resultant bistability in Bernal-stacked bilayer graphene aligned to its insulating hexagonal boron nitride gate dielectrics were discovered.

Robust superconductivity in magic-angle multilayer graphene family.

The discovery of correlated states and superconductivity in magic-angle twisted bilayer graphene (MATBG) established a new platform to explore interaction-driven and topological phenomena. However, despite multitudes of correlated phases observed in moiré systems, robust superconductivity appears the least common, found only in MATBG and more recently in magic-angle twisted trilayer graphene. Here we report the experimental realization of superconducting magic-angle twisted four-layer and five-layer graphene, hence establishing alternating twist magic-angle multilayer graphene as a robust family of moiré superconductors.

Effect of Different Iron Sources on Growth of Zeolitic Imidazolate Frameworks-8: For Efficient Oxygen Reduction Electrocatalysts.

Transition metal and nitrogen co-doped carbon-based catalysts (TM-N-C) have become the most promising catalysts for Pt/C due to their wide range of sources, low cost, high catalytic activity, excellent stability and strong resistance to poisoning, especially Fe-N-C metal-organic frameworks (MOFs), which are some of the most promising precursors for the preparation of Fe-N-C catalysts due to their inherent properties, such as their highly ordered three-dimensional framework structure, controlled porosity, and tuneable chemistry. Based on these, in this paper, different iron sources were added to synthesis a sort of zeolitic imidazole frameworks (ZIF-8). Then the imidazole salt in ZIF-8 was rearranged into high N-doped carbon by high-temperature pyrolysis to prepare the Fe-N-C catalyst.

Various Morphology of WO₃ Modified Activated Carbon Supported Pd Catalysts with Enhanced Formic Acid Electrooxidation.

Activated carbon support Pd nanoparticles (NPs) modified by various WO₃-shaped catalysts were prepared and applied as an efficient anode catalyst for direct formic acid fuel cells. Three forms of WO₃ (nanosheets, nanoparticles, nanobars) modified activated carbon hybrids were first prepared via different syntheses, and then used as supports to synthesize three types of Pd-WO₃/C catalysts by a NaBH4 reduction method. The morphology, structure, and electrochemical performances of the as-prepared Pd-WO₃/C catalysts were characterized and analyzed.

Urbanization threaten the pollination of Gentiana dahurica.

With rapid spread of the urbanization, many environmental factors, such as climate, soil pH and nutrients have been changed. However, the plant pollination affected by urbanization was seldom conducted. Here, we studied the flower visitation rates, seed production, pollen limitation and flower morphological characters of Gentiana dahurica at 3 populations along an urban-peri-urban gradient around Xi'ning over 4 consecutive years, aiming to test the effects of urbanization on plant pollination service.

Electrocatalytic oxidation of ethanol and ethylene glycol on cubic, octahedral and rhombic dodecahedral palladium nanocrystals.

Cubic, octahedral and rhombic dodecahedral Pd nanocrystals were synthesized and examined as nanocatalysts for electro-oxidation of ethanol and ethylene glycol. Combined electrochemical measurements and density functional theory calculations reveal that nanofacet-dependent affinity and reactivity of OH and CO are closely linked to the C2 alcohol oxidation activities, with the highest reactivity found on the Pd nanocubes bounded by {100} facets.

All-trans retinoic acid enhances cytotoxicity of CIK cells against human lung adenocarcinoma by upregulating MICA and IL-2 secretion.

To determine the growth inhibition capability of all-trans retinoic acid (ATRA) with cytokine-induced killer cells (CIKs), we evaluated their effects, alone and in combination, on human lung carcinoma A549 cells. CIKs treated with ATRA significantly inhibited cell growth. Additionally, CIK with ATRA synergistically inhibited migration and invasiveness, colony formation of A549 and NCI-H520 cells.

Cholecystokinin octapeptide inhibits immunoglobulin G1 production of lipopolysaccharide-activated B cells.

Cholecystokinin octapeptide (CCK-8) is a typical brain-gut peptide that exerts a variety of physiological actions in both the peripheral and central nervous systems. Our laboratory has previously reported that CCK-8 produces immunoregulatory action through activating CCK receptor (CCK1R/CCK2R) expression on immune cell surfaces. In the present study, we investigated the effect of CCK-8 on immunoglobulin G1 (IgG1) production in lipopolysaccharide (LPS)-activated B cells in vitro.

Cholecystokinin octapeptide regulates lipopolysaccharide-activated B cells co-stimulatory molecule expression and cytokines production in vitro.

Cholecystokinin octapeptide (CCK8) can exert the immunoregulatory roles through activating immune cell surface receptors such as T lymphocytes, macrophages, dendritic cells, and so on. In this study, we discussed the effects of CCK8 on lipopolysaccharide (LPS)-activated B cells in terms of the expression of co-stimulatory molecules, and the capacity to activate CD4(+) T cells and cytokines production in vitro. The results revealed that B cells expressed two types of CCK receptors; CCK8 inhibited the expression of co-stimulatory molecules such as CD80 and CD86 on LPS-activated B cells, suppressed the proliferation of allogeneic T cells in a dose-dependent manner, and also reduced the secretion of Th1-type cytokine IFN-γ, whereas enhanced the secretion of Th2-type cytokine IL-4 by LPS-activated B cells.

Application of surface-enhanced infrared absorption spectroscopy to investigate pyridine adsorption on platinum-group electrodes.

In situ surface-enhanced infrared absorption spectroscopy (SEIRAS) was applied to investigate adsorption configurations of pyridine (Py) on platinum, palladium, ruthenium, and rhodium nanoparticle film electrodes. The results reveal that alpha-pyridyl species predominantly form on Pt electrodes by assuming an edge-on configuration with its ring N and alpha-C atoms bonding to the Pt surface, while on Ru and Rh electrodes pyridine molecules essentially remain intact by adopting a slightly edge-tilted configuration through bonding with its N lone pair electrons. Py adsorption on a Pd electrode may lie in between the above two cases; both alpha-pyridyl species and edge-tilted intact pyridine could be significantly present.

Practically modified attenuated total reflection surface-enhanced IR absorption spectroscopy for high-quality frequency-extended detection of surface species at electrodes.

A practically modified ATR configuration has been proposed for in situ electrochemical surface-enhanced IR absorption spectroscopy (SEIRAS) by sandwiching an ultrathin water interlayer between a hemicylindrical ZnSe prism and a Si wafer as an integrated window. This new ATR optics significantly enhances the throughput of an effective IR beam across the ZnSe/gap/Si/metal film, enabling high-quality spectral fingerprints down to 700 cm(-1) to be readily detected at larger incidence angles without compromising the electrochemical feasibility and stability of metallic films deposited on Si. The advantages of this modified ATR-SEIRAS have been initially applied to explore two selected systems: wide-ranged in situ ATR-SEIRA spectra provided strong evidence in support of the formate intermediate pathway for methanol electrooxidation at the Pt electrode in an acid solution; in addition, new spectral fingerprints revealed comprehensive orientational information about of the p-nitrobenzoate species at Pt electrode as a result of the dissociative adsorption of p-nitrobenzoic acid molecules from an acid solution.

Genetic diversity of five Kobresia species along the eastern Qinghai-Tibet plateau in China.

Plants of the genus Kobresia are alpine grass species of high ecological and economic importance. Vegetative growth is the dominant means of reproduction for the Kobresia. Studies suggest that substantial vegetative growth can reduce genetic diversity and renders populations less able to buffer changing and extreme conditions.

Seeded-growth approach to fabrication of silver nanoparticle films on silicon for electrochemical ATR surface-enhanced IR absorption spectroscopy.

Ag nanoparticle films (simplified as nanofilms hereafter) on Si for electrochemical ATR surface enhanced IR absorption spectroscopy (ATR-SEIRAS) have been successfully fabricated by using chemical deposition, which incorporates initial embedding of Ag seeds on the reflecting plane of an ATR Si prism and subsequent chemical plating of conductive and SEIRA-active Ag nanofilms. Two alternative methods for embedding initial Ag seeds have been developed: one is based on self-assembly of Ag colloids on an aminosilanized Si surface, whereas the other the reduction of Ag+ in a HF-containing solution. A modified silver-mirror reaction was employed for further growth of Ag seeds into Ag nanofilm electrodes with a theoretically average thickness of 40-50 nm.

Tunable surface-enhanced infrared absorption on au nanofilms on si fabricated by self-assembly and growth of colloidal particles.

Au colloids were used to fabricate nanoscale-tunable Au nanofilms on silicon for surface-enhanced IR absorption bases in both ambient and electrochemical environments. This wet process incorporates the self-assembly of colloidal Au monolayer using 3-aminopropyl trimethoxysilane as the organic coupler with subsequent chemical plating in an Au(III)/hydroxylamine solution. FTIR spectroscopy in transmission mode of the probe species SCN- was used to evaluate the apparent surface enhancement in IR absorption of 2D Au colloid arrays and chemically plated Au particles.

Ubiquitous strategy for probing ATR surface-enhanced infrared absorption at platinum group metal-electrolyte interfaces.

A versatile two-step wet process to fabricate Pt, Pd, Rh, and Ru nanoparticle films (simplified as nanofilms hereafter) for in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) study of electrochemical interfaces is presented, which incorporates an initial chemical deposition of a gold nanofilm on the basal plane of a silicon prism with the subsequent electrodepostion of desired platinum group metal overlayers. Galvanostatic electrodeposition of Pt, Rh, and Pd from phosphate or perchloric acid electrolytes, or potentiostatic electrodeposition of Ru from a sulfuric acid electrolyte, yields sufficiently "pinhole-free" overlayers as evidenced by electrochemical and spectroscopic characterizations. The Pt group metal nanofilms thus obtained exhibit strongly enhanced IR absorption.

Antitumor activity and immune enhancement of murine interleukin-23 expressed in murine colon carcinoma cells.

Interleukin (IL)-23, a cytokine composed of p19 and the p40 subunit of IL-12, can enhance the proliferation of memory T cells and production of IFN-gamma from activated T cells. It can also induce antitumor effects in murine model. To further evaluate the antitumor activity and immune enhancement of IL-23 in vivo, murine colon carcinoma cells retrovirally transduced with mIL-23 gene were injected subcutaneously (s.

Extending in situ attenuated-total-reflection surface-enhanced infrared absorption spectroscopy to ni electrodes.

Surface-enhanced infrared absorption spectroscopy (SEIRAS) in the attenuated-total-reflection configuration (ATR-SEIRAS) has been applied for the first time to Ni electrodes. SEIRA-active Ni electrodes were obtained through initial chemical deposition of a 60-nm-thick Au underlayer on the reflecting plane of an ATR Si prism followed by potentiostatic electrodeposition of a 40-nm-thick Ni overlayer in a modified Watt's electrolyte. The Ni nanoparticle film thus obtained exhibited exceptionally enhanced IR absorption for the surface probe molecule CO while maintaining unipolar and normally directed bands.

[Effect of IL-24 gene expression on the growth of glioma cells in vitro and in vivo].

Objective: To investigate the effect of IL-24 expression on the growth of glioma cells.

Methods: The IL-24 gene was transfected into rat glioma C6 cells with a retroviral vector. The expression of IL-24 in C6/IL-24 glioma cells was confirmed by RT-PCR.

[Expression of IL-23 gene in murine colon carcinoma cells transduced with recombinant retrovirus and its anti-tumor activity].

Aim: To obtain murine colon carcinoma cell lines stably transducted by recombinant retrovirus encoding mIL-23 gene.

Methods: The retrovirus vector was used to transduce the mIL-23 gene into murine colon carcinoma cells (Colon26) and stable clones expressing mIL-23 (Colon26/IL-23) were obtained by screening with G418. The expression of mIL-23 gene was detected by PCR and RT-PCR.

[Retrovirus-mediated IL-18 gene expression in rat C6 glioma cell line].

Aim: To set up rat C6 glioma cell line C6/IL-18 expressing IL-18 gene and explore the effect of IL-18 on the growth of C6 cells.

Methods: The IL-18 gene was transferred into the C6 cells by a retrovirus vector. After screening with G418, the C6/IL-18 cells were obtained.

[Experimental study on anti-tumor effects of cortex Acanthopanacis senticosus in vivo and in vitro].

Objective: To provide a basis for development and preparation of the new anti-tumor agents from Cortex A-canthopanacis senticosus (CAS), through isolating the active substances from CAS and studying the anti-tumor effect of CAS extracts in vivo and in vitro.

Methods: The effects of CAS extracts and its isolated ingredients on tumor cell proliferation in vitro was determined by 3H-TdR incorporation; the anti-tumor component of CAS was isolated and purified by chromatography; the tumor bearing mice model was established by injecting tumor cell subcutaneously, and the model was used to observe the anti-tumor effect of CAS extract administered through gastrogavage.

Results: CAS extract showed obvious inhibition on tumor cell proliferation originated from multiple tissues (P < 0.

[Extracorporeal experimental study on immuno-modulatory activity of Astragalus memhranaceus extract].

Objective: To study the effect of Astragalus membranaceus extract (AME) in regulating the immune function of human peripheral blood immune cells (PBIC) in vitro.

Methods: Effects of AME on the proliferation activity of peripheral blood mononuclear cells (PBMC) and the tumor cell phagocytosis of peripheral blood adherent monocytes (PBAM) were measured by using 3H-TdR incorporation. Effect of the tumor-killing activity of cytotoxic T-lymphocyte (CTL) was determined by using 51Cr-releasing assay.