1,013 research outputs found
Emergence of hysteresis loop in social contagions on complex networks
Understanding the spreading mechanisms of social contagions in complex network systems has attracted much attention in the physics community. Here we propose a generalized threshold model to describe social contagions. Using extensive numerical simulations and theoretical analyses, we find that a hysteresis loop emerges in the system. Specifically, the steady state of the system is sensitive to the initial conditions of the dynamics of the system. In the steady state, the adoption size increases discontinuously with the transmission probability of information about social contagions, and trial size exhibits a non-monotonic pattern, i.e., it first increases discontinuously then decreases continuously. Finally we study social contagions on heterogeneous networks and find that network topology does not qualitatively affect our results.This work was funded in part by the National Key Research and Development Program (Grant No. 2016YFB0800602), the National Natural Science the Foundation of China (Grant Nos 61472045,61573067), and the China Scholarship Council. (2016YFB0800602 - National Key Research and Development Program; 61472045 - National Natural Science the Foundation of China; 61573067 - National Natural Science the Foundation of China; China Scholarship Council)Published versio
Magnitude of Magnetic Field Dependence of a Possible Selective Spin Filter in ZnSe/Zn_{1-x}Mn_{x}Se Multilayer Heterostructure
Spin-polarized transport through a band-gap-matched ZnSe/Zn_{1-x}Mn_{x}
Se/ZnSe/Zn_{1-x}Mn_{x}Se/ZnSe multilayer structure is investigated. The
resonant transport is shown to occur at different energies for different spins
owing to the split of spin subbands in the paramagnetic layers. It is found
that the polarization of current density can be reversed in a certain range of
magnetic field, with the peak of polarization moving towards a stronger
magnetic field for increasing the width of central ZnSe layer while shifting
towards an opposite direction for increasing the width of paramagnetic layer.
The reversal is limited in a small-size system. A strong suppression of the
spin up component of the current density is present at high magnetic field. It
is expected that such a reversal of the polarization could act as a possible
mechanism for a selective spin filter device
Time-Dependent Spin-Polarized Transport Through a Resonant Tunneling Structure with Multi-Terminal
The spin-dependent transport of the electrons tunneling through a resonant
tunneling structure with ferromagnetic multi-terminal under dc and ac fields is
explored by means of the nonequilibrium Green function technique. A general
formulation for the time-dependent current and the time-averaged current is
established. As its application the systems with two and three terminals in
noncollinear configurations of the magnetizations under dc and ac biases are
investigated, respectively. The asymmetric factor of the relaxation times for
the electrons with different spin in the central region is uncovered to bring
about various behaviours of the TMR. The present three-terminal device is
different from that discussed in literature, which is coined as a spin
transistor with source. The current-amplification effect is found. In addition,
the time-dependent spin transport for the two-terminal device is studied. It is
found that the photonic sidebands provide new channels for the electrons
tunneling through the barriers, and give rise to new resonances of the TMR,
which is called as the photon-asisted spin-dependent tunneling. The asymmetric
factor of the relaxation times is observed to lead to additional resonant peaks
besides the photon-asisted resonances.Comment: 32 pages,14 figure
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Extracellular RNA in a single droplet of human serum reflects physiologic and disease states.
Extracellular RNAs (exRNAs) are present in human serum. It remains unclear to what extent these circulating exRNAs may reflect human physiologic and disease states. Here, we developed SILVER-seq (Small Input Liquid Volume Extracellular RNA Sequencing) to efficiently sequence both integral and fragmented exRNAs from a small droplet (5 ÎĽL to 7 ÎĽL) of liquid biopsy. We calibrated SILVER-seq in reference to other RNA sequencing methods based on milliliters of input serum and quantified droplet-to-droplet and donor-to-donor variations. We carried out SILVER-seq on more than 150 serum droplets from male and female donors ranging from 18 y to 48 y of age. SILVER-seq detected exRNAs from more than a quarter of the human genes, including small RNAs and fragments of mRNAs and long noncoding RNAs (lncRNAs). The detected exRNAs included those derived from genes with tissue (e.g., brain)-specific expression. The exRNA expression levels separated the male and female samples and were correlated with chronological age. Noncancer and breast cancer donors exhibited pronounced differences, whereas donors with or without cancer recurrence exhibited moderate differences in exRNA expression patterns. Even without using differentially expressed exRNAs as features, nearly all cancer and noncancer samples and a large portion of the recurrence and nonrecurrence samples could be correctly classified by exRNA expression values. These data suggest the potential of using exRNAs in a single droplet of serum for liquid biopsy-based diagnostics
Effects of R-parity violating supersymmetry in top pair production at linear colliders with polarized beams
In the minimal supersymmetric standard model with R-parity violation, the
lepton number violating top quark interactions can contribute to the top pair
production at a linear collider via tree-level u-channel squark exchange
diagrams. We calculate such contributions and find that in the allowed range of
these R-violating couplings, the top pair production rate as well as the top
quark polarization and the forward-backward asymmetry can be significantly
altered. By comparing the unpolarized beams with the polarized beams, we find
that the polarized beams are more powerful in probing such new physics.Comment: 10 pages, 6 fig
Attacking practical quantum key distribution system with wavelength dependent beam splitter and multi-wavelength sources
Unconditional security of quantum key distribution protocol can be guaranteed
by the basic property of quantum mechanics. Unfortunately, the practical
quantum key distribution system always have some imperfections, and the
practical system may be attacked if the imperfection can be controlled by the
eavesdropper Eve. Applying the fatal security loophole introduced by the
imperfect beam splitter's wavelength dependent optical property, we propose
wavelength-dependent attacking model, which can be applied to almost all
practical quantum key distribution systems with the passive state modulation
and photon state detection after the practical beam splitter. Utilizing our
attacking model, we experimentally demonstrate the attacking system based on
practical polarization encoding quantum key distribution system with almost
100% success probability. Our result demonstrate that all practical devices
require tightened security inspection for avoiding side channel attacks in
practical quantum key distribution experimental realizations
Sequencing of p53 mutation in established human hepatocellular carcinoma cell line of HHC4 and HHC15 in nude mice
AIM To set up cell lines of human hepatocellular carcinoma in nude mice for the research of cell biology and gene therapy. METHODS Xenotransplantation of human hepatoma into nude mice was carried out and the growth rate, histopathology and immunology of the nude mice were studied. The DNA from xenografts were analyzed by HBV gene and PCR amplification of a fragment of p53 gene exon 7, which were identified by dot blot hybridization, restriction fragments length polymorphism and DNA sequencing. RESULTS hHCC4 and hHCC415 cell lines could be successively transplanted in nude mice and the population doubling time was 7 and 5 days respectively. These strains retained the original characteristics of histopathology, secreting AFP and heteroploid karyotypes in human hepatocellular carcinoma. The fragment of HBV gene was detected in the genomic DNA of both hHCC4 and hHCC15, however only hHCC4 secreted HBsAg. The mutation at 250 code (C-->A) and 249 code (G --> T) were detected respectively in the genomic DNA of hHCC4 and hHCC15. CONCLUSION The two cell lines are useful material for studying cell biology and gene therapy in human hepatocellular carcinoma and provide molecular biological trace of the relationship between high mortality of hepatoma and AFB1 severe pollution of the daily common foods in this district
A Panel of Serum MicroRNAs as Specific Biomarkers for Diagnosis of Compound- and Herb-Induced Liver Injury in Rats
Drug-induced liver injury (DILI) has been a public, economic and pharmaceutical issue for many years. Enormous effort has been made for discovering and developing novel biomarkers for diagnosing and monitoring both clinical and preclinical DILI at an early stage, though progress has been relatively slow. Additionally, herb-induced liver injury is an emerging cause of liver disease because herbal medicines are increasingly being used worldwide. Recently, circulating microRNAs (miRNAs) have shown potential to serve as novel, minimally invasive biomarkers to diagnose and monitor human cancers and other diseases at early stages.In order to identify candidate miRNAs as diagnostic biomarkers for DILI, miRNA expression profiles of serum and liver tissue from two parallel liver injury Sprague-Dawley rat models induced by a compound (acetaminophen, APAP) or an herb (Dioscorea bulbifera, DB) were screened in this study. The initial screens were performed on serum using a MicroRNA TaqMan low-density qPCR array and on liver tissue using a miRCURY LNA hybridization array and were followed by a TaqMan probe-based quantitative reverse transcription-PCR (qRT-PCR) assay to validate comparison with serum biochemical parameters and histopathological examination. Two sets of dysregulated miRNA candidates in serum and liver tissue were selected in the screening phase. After qRT-PCR validation, a panel of compound- and herb- related serum miRNAs was identified.We have demonstrated that this panel of serum miRNAs provides potential biomarkers for diagnosis of DILI with high sensitivity and specificity
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