2,812 research outputs found

    Perfect valley filter based on topological phase in disordered Sb\rm{Sb} Monolayer Heterostructure

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    The hydrogenated Sb\rm{Sb} monolayer epitaxially grown on a LaFeO3\rm{LaFeO_3} substrate is a novel type of two-dimensional material hosting quantum spin-quantum anomalous Hall (QS-QAH) states. For a device formed by Sb\rm{Sb} monolayer ribbon, the QAH edge states, belong to a single valley, are located at opposite edges of the ribbon. The QSH edge states, on the other hand, belong to the other valley and are distributed in a very narrow region at the same edge. In this paper, we find such material can be used to fabricate perfect valley filter. Adopting scattering matrix method and Green's function method, the valley resolved transport and spatial distribution of local current are calculated, in the present of Anderson disorder, edge defects and edge deformations. The numerical results demonstrate that, in the presence of above three types of disorder with moderate strength, the carriers can flow disspationless with nearly perfect valley polarization. Moreover, when the device becomes longer, the transport current does not decrease while the valley filter works even better. The origin is that the disorder can destroy the QSH edge states, but the valley-polarized QAH edge states can well hold.Comment: 5 figure

    TNFα induces Ca2+ influx to accelerate extrinsic apoptosis in hepatocellular carcinoma cells

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    BACKGROUND: Tumor necrosis factor-α has been proven an effective anticancer agent in preclinical studies. However, the translation of TNFα from research to clinic has been blocked by significant systemic toxicity and limited efficacy at maximal tolerated dose, which need urgently to be solved. METHODS: The level of cytosolic Ca RESULTS: Here, we demonstrated that TNFα induced extracellular Ca CONCLUSIONS: Our study provides the evidence supporting a novel mechanism by which TNFα induces extracellular C

    Encapsulation of hydrophobic phthalocyanine with poly(N-isopropylacrylamide)/lipid composite microspheres for thermo-responsive release and photodynamic therapy

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    Phthalocyanine (Pc) is a type of promising sensitizer molecules for photodynamic therapy (PDT), but its hydrophobicity substantially prevents its applications. In this study, we efficiently encapsulate Pc into poly(N-isopropylacrylamide) (pNIPAM) microgel particles, without or with lipid decoration (i.e., Pc@pNIPAM or Pc@pNIPAM/lipid), to improve its water solubility and prevent aggregation in aqueous medium. The incorporation of lipid molecules significantly enhances the Pc loading efficiency of pNIPAM. These Pc@pNIPAM and Pc@pNIPAM/lipid composite microspheres show thermo-triggered release of Pc and/or lipid due to the phase transition of pNIPAM. Furthermore, in the in vitro experiments, these composite particles work as drug carriers for the hydrophobic Pc to be internalized into HeLa cells. After internalization, the particles show efficient fluorescent imaging and PDT effect. Our work demonstrates promising candidates in promoting the use of hydrophobic drugs including photosensitizers in tumor therapies

    Enhanced Neuroactivation during Working Memory Task in Postmenopausal Women Receiving Hormone Therapy: A Coordinate-Based Meta-Analysis

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    Background and Aim: Hormone therapy (HT) has long been thought beneficial for controlling menopausal symptoms and human cognition. Studies have suggested that HT has a positive association with working memory, but no consistent relationship between HT and neural activity has been shown in any cognitive domain. The purpose of this meta-analysis was to assess the convergence of findings from published randomized control trials studies that examined brain activation changes in postmenopausal women. Methods: A systematic search for fMRI studies of neural responses during working memory tasks in postmenopausal women was performed. Studies were excluded if they were not treatment studies and did not contain placebo or blank controls. For the purpose of the meta-analysis, 8 studies were identified, with 103 postmenopausal women taking HT and 109 controls. Results: Compared with controls, postmenopausal women who took HT increased activation in the left frontal lobe, including superior frontal gyrus (BA 8), right middle frontal gyrus (BA 9), anterior lobe, paracentral lobule (BA 7), limbic lobe, and anterior cingulate (BA 32). Additionally, decreased activation is noted in the right limbic lobe, including parahippocampal gyrus (BA 28), left parietal lobe, and superior parietal lobule (BA 7). All regions were significant at p ≤ 0.05 with correction for multiple comparisons. Conclusion: Hormone treatment is associated with BOLD signal activation in key anatomical areas during fMRI working memory tasks in healthy hormone-treated postmenopausal women. A positive correlation between activation and task performance suggests that hormone use may benefit working memory

    Oxidative Stress Amelioration of Novel Peptides Extracted from Enzymatic Hydrolysates of Chinese Pecan Cake

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    Pecan (Carya cathayensis) is an important economic crop, and its hydrolyzed peptides have been evidenced to reduce the effect of oxidative stress due to their antioxidant capacity. Hence, the protocols of ultrafiltration and gel filtration chromatography were established to obtain bioactive peptides from by-products of C. cathayensis (pecan cake). As measured by DPPH/ABTS radical scavenging, the peptides with less molecular weight (MW) possess higher antioxidant capacity. PCPHIII (MW < 3 kDa) presented higher radical scavenging capacity than PCPH-II (3 kDa < MW < 10 kDa) and PCPH-I (MW > 10 kDa) measured by DPPH (IC50: 111.0 g/ mL) and measured by ABTs (IC50: 402.9 g/mL). The secondary structure and amino acid composition varied by their MW, in which PCPH-II contained more -helices (26.71%) and -sheets (36.96%), PCPH-III contained higher ratios of -turns (36.87%), while the composition of different secondary of PCPH-I was even 25 5.76%. The variation trend of -helix and random experienced slightly varied from PCPH-I to PCPH-II, while significantly decreased from PCPH-II to PCPH-III. The increasing antioxidant capacity is followed by the content of proline, and PCPH-III had the highest composition (8.03%). With regard to the six peptides identified by LC-MS/MS, two of them (VYGYADK and VLFSNY) showed stronger antioxidant capacity than others. In silico molecular docking demonstrated their combining abilities with a transcription factor Kelch-like ECH-associated protein 1 (Keap1) and speculated that they inhibit oxidative stress through activating the Keap1-Nrf2-ARE pathway. Meanwhile, increased activity of SOD and CAT—antioxidant markers—were found in H2O2-induced cells. The residue of tyrosine was demonstrated to contribute the most antioxidant capacity of VYGYADK and its position affected less. This study provided a novel peptide screening and by-product utilization process that can be applied in natural product developments.People's Government of Zhejiang ProvinceChinese Academy of Forestry 2019SY03Natural Science Foundation of Xinjiang Uygur Autonomous Region 2021D01A7

    All-fiber CW cylindrical vector beam fiber laser based on few-mode fiber Bragg grating

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    An all-fiber CW cylindrical vector beam (CVB) fiber laser based on a few-mode fiber Bragg grating (FW-FBG) with switchable radially and azimuthally polarized beam generation has been demonstrated. The CVB fiber laser operates at a wavelength of 1053.95 nm with a 3 dB line width of 0.1 nm, a signal-to-background ratio of more than 50 dB. The CVB output power can reach 75 mW, and the mode purity is measured to be >95.5%. This compact CVB fiber laser has potential applications in many areas such as optical tweezers, optical trapping and optical sensing systems

    Composite federated learning with heterogeneous data

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    We propose a novel algorithm for solving the composite Federated Learning (FL) problem. This algorithm manages non-smooth regularization by strategically decoupling the proximal operator and communication, and addresses client drift without any assumptions about data similarity. Moreover, each worker uses local updates to reduce the communication frequency with the server and transmits only a dd-dimensional vector per communication round. We prove that our algorithm converges linearly to a neighborhood of the optimal solution and demonstrate the superiority of our algorithm over state-of-the-art methods in numerical experiments
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