750 research outputs found

    Anomalous Cooper pair interference on Bi2Te3 surface

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    It is believed that the edges of a chiral p-wave superconductor host Majorana modes, relating to a mysterious type of fermions predicted seven decades ago. Much attention has been paid to search for p-wave superconductivity in solid-state systems, including recently those with strong spin-orbit coupling (SOC). However, smoking-gun experiments are still awaited. In this work, we have performed phase-sensitive measurements on particularly designed superconducting quantum interference devices constructing on the surface of topological insulators Bi2Te3, in such a way that a substantial portion of the interference loop is built on the proximity-effect-induced superconducting surface. Two types of Cooper interference patterns have been recognized at low temperatures. One is s-wave like and is contributed by a zero-phase loop inhabited in the bulk of Bi2Te3. The other, being identified to relate to the surface states, is anomalous for that there is a phase shift between the positive and negative bias current directions. The results support that the Cooper pairs on the surface of Bi2Te3 have a 2\pi Berry phase which makes the superconductivity p_x+ip_y-wave-like. Mesoscopic hybrid rings as constructed in this experiment are presumably arbitrary-phase loops good for studying topological quantum phenomena.Comment: supplementary material adde

    Spectral and energy efficiency analysis for massive MIMO multi-pair two-way relaying networks under generalized power scaling

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    In this work, we investigate the spectral efficiency (SE) and energy efficiency (EE) for a massive multiple-input multiple-output multi-pair two-way amplify-and-forward relaying system, where multi-pair users exchange information via a relay station equipped with large scale antennas. We assume that imperfect channel state information is available and maximum-ratio combining/maximum-ratio transmission beamforming is adopted at the relay station. Considering constant or scaled transmit power of pilot sequences, we quantify the asymptotic SE and EE under general power scaling schemes, in which the transmit power at each user and relay station can both be scaled down, as the number of relay antennas tends to infinity. In addition, a closed-form expression of the SE has been obtained approximately. Our results show that by using massive relay antennas, the transmit power at each user and the relay station can be scaled down, with a non-vanishing signal to interference and noise ratio (SINR). Finally, simulation results confirm the validity of our analysis

    MiR-103-3p promotes hepatic steatosis to aggravate nonalcoholic fatty liver disease by targeting of ACOX1

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    BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a major risk factor for hepatocellular carcinoma, and alterations in miRNA expression are related to the development of NAFLD. However, the role of miRNAs in regulating the development of NAFLD is still poorly understood. METHODS: We used qRT-PCR to detect the level of miR-103-3p in both cell and mouse models of NAFLD. Biochemical assays, DCF-DA assays, Oil red O staining and HE staining were used to detect the role of miR-103-3p in NAFLD development. Target genes of miR-103-3p were predicted using the TargetScan database and verified by qRT-PCR, western blot and dual-luciferase assays. RESULTS: The expression of miR-103-3p increased in both NAFLD model cells and liver tissues from the NAFLD mouse model. Inhibition of miR-103-3p significantly alleviated the accumulation of lipid droplets in free fatty acid-treated L02 cells and liver tissues from mice with NAFLD. Inhibition of miR-103-3p reduced the contents of H CONCLUSIONS: These findings identified a negative regulatory mechanism between ACOX1 and miR-103-3p that promotes the pathogenesis of NAFLD and suggested that inhibition of miR-103-3p may be a potential treatment strategy for NAFLD

    Fluorescence Detection of Cancer Stem Cell Markers Using a Sensitive Nano-Aptamer Sensor.

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    Antigen CD133 is a glycoprotein present on the surface of cancer stem cells (CSCs), which is a key molecule to regulate the fate of stem cells and a functional marker of stem cells. Herein, a novel fluorescence turn-on nano-aptamer sensor for quantifying CD133 was designed using hybridization between CD133-targeted aptamers and partially complementary paired RNA (ssRNA), which were modified on the surface of quantum dots (QDs) and gold nanoparticles (AuNPs), respectively. Owing to the hybridization of aptamers and ssRNA, the distance between QDs and AuNPs was shortened, which caused fluorescence resonance energy transfer (FRET) between them, and the florescence of QDs was quenched by AuNPs. When CD133 competitively replaced ssRNA and was bound to aptamers, AuNPs-ssRNA could be released, which led to a recovery of fluorescent signals of QDs. The increase in the relative value of fluorescence intensity was investigated to linearly correlate with the CD133 concentration in the range of 0-1.539 μM, and the detection limit was 6.99 nM. In confocal images of A549 cells, the CD133 aptamer sensor was further proved applicable in lung cancer cell samples with specificity, precision, and accuracy. Compared with complicated methods, this study provided a fresh approach to develop a highly sensitive and selective detection sensor for CSC markers

    4-Acetyl-2,3,4,5-tetra­hydro-1H-1,4-benzodiazepine

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    The title compound, C11H14N2O·H2O, crystallizes with one formula unit in the asymmetric unit. The seven-membered ring has a chair conformation with the C=O group turned away from the benzene ring. N—H⋯O and O—H⋯O hydrogen bonds are present in the crystal structure

    Pyrotinib and chrysin synergistically potentiate autophagy in HER2-positive breast cancer

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    Human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) has been the most challenging subtype of BC, consisting of 20% of BC with an apparent correlation with poor prognosis. Despite that pyrotinib, a new HER2 inhibitor, has led to dramatic improvements in prognosis, the efficacy of pyrotinib monotherapy remains largely restricted due to its acquired resistance. Therefore, identifying a new potential antitumor drug in combination with pyrotinib to amplify therapeutic efficacy is a pressing necessity. Here, we reported a novel combination of pyrotinib with chrysin and explored its antitumor efficacy and the underlying mechanism in HER2-positive BC. We determined that pyrotinib combined with chrysin yielded a potent synergistic effect to induce more evident cell cycle arrest, inhibit the proliferation of BT-474 and SK-BR-3 BC cells, and repress in vivo tumor growth in xenograft mice models. This may be attributed to enhanced autophagy induced by endoplasmic reticulum stress. Furthermore, the combined treatment of pyrotinib and chrysin induced ubiquitination and glucose-6-phosphate dehydrogenase (G6PD) degradation by upregulating zinc finger and BTB/POZ domain-containing family protein 16 (ZBTB16) in tumorigenesis of BC. Mechanistically, we identified that miR-16-5p was a potential upstream regulator of ZBTB16, and it showed a significant inverse correlation with ZBTB16. Inhibition of miR-16-5p overexpression by restoring ZBTB16 significantly potentiated the overall antitumor efficacy of pyrotinib combined with chrysin against HER2-positive BC. Together, these findings demonstrate that the combined treatment of pyrotinib and chrysin enhances autophagy in HER2-positive BC through an unrecognized miR-16-5p/ZBTB16/G6PD axis.</p

    Exploring functional metabolites and proteomics biomarkers in late-preterm and natural-born pigs

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    IntroductionPigs are often used to study the intestinal development of newborns, particularly as preterm pig models that mimic the intestinal growth of human preterm infants. Neonatology’s study of delivery mode’s impact on neonatal development is crucial.MethodsWe established 14 newborn pigs delivered via cesarean sections (C-section, at 113 days of gestational age, CS group) and 8 naturally born pigs were used as controls (at 114 days of gestational age, NF group). The impact of two alternative delivery procedures (C-section and natural birth) on the levels of short-chain fatty acids (SCFAs) and organic acids in the hepatic and intestines of newborn pigs were compared using metabolomics. The underlying molecular pathways are examined at the “protein-metabolite” level by integrating proteomic data.ResultsThe findings demonstrated that the mode of delivery changed the metabolism of SCFAs in newborn pigs, perhaps by affecting the physiology levels of cyclic intermediates such as lactate and malate in the pyruvate metabolic pathway. Additionally, by participating in the fatty acid metabolism pathway, two distinct proteins (FASN and HSD17B4) may impact the physiological concentration of these tiny metabolites.DiscussionIn conclusion, this study provided reliable animal model data for understanding the physiological SCFA metabolic information and its affecting mechanism of large-gestational age preterm infants
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