13,123 research outputs found
Electronic transport of bilayer graphene with asymmetry line defects
In this paper, we study the quantum properties of a bilayer graphene with
(asymmetry) line defects. The localized states are found around the line
defects. Thus, the line defects on one certain layer of the bilayer graphene
can lead to an electric transport channel. By adding a bias potential along the
direction of the line defects, we calculate the electric conductivity of
bilayer graphene with line defects using Landauer-B\"{u}ttiker theory, and show
that the channel affects the electric conductivity remarkably by comparing the
results with those in a perfect bilayer graphene. This one-dimensional line
electric channel has the potential to be applied in the nanotechnology
engineering.Comment: 5 pages, 7 figure
Long-term Blood Pressure Prediction with Deep Recurrent Neural Networks
Existing methods for arterial blood pressure (BP) estimation directly map the
input physiological signals to output BP values without explicitly modeling the
underlying temporal dependencies in BP dynamics. As a result, these models
suffer from accuracy decay over a long time and thus require frequent
calibration. In this work, we address this issue by formulating BP estimation
as a sequence prediction problem in which both the input and target are
temporal sequences. We propose a novel deep recurrent neural network (RNN)
consisting of multilayered Long Short-Term Memory (LSTM) networks, which are
incorporated with (1) a bidirectional structure to access larger-scale context
information of input sequence, and (2) residual connections to allow gradients
in deep RNN to propagate more effectively. The proposed deep RNN model was
tested on a static BP dataset, and it achieved root mean square error (RMSE) of
3.90 and 2.66 mmHg for systolic BP (SBP) and diastolic BP (DBP) prediction
respectively, surpassing the accuracy of traditional BP prediction models. On a
multi-day BP dataset, the deep RNN achieved RMSE of 3.84, 5.25, 5.80 and 5.81
mmHg for the 1st day, 2nd day, 4th day and 6th month after the 1st day SBP
prediction, and 1.80, 4.78, 5.0, 5.21 mmHg for corresponding DBP prediction,
respectively, which outperforms all previous models with notable improvement.
The experimental results suggest that modeling the temporal dependencies in BP
dynamics significantly improves the long-term BP prediction accuracy.Comment: To appear in IEEE BHI 201
The Simulation of Non-Abelian Statistics of Majorana Fermions in Ising Chain with Z2 Symmetry
In this paper, we numerically study the non-Abelian statistics of the
zero-energy Majorana fermions on the end of Majorana chain and show its
application to quantum computing by mapping it to a spin model with special
symmetry. In particular, by using transverse-field Ising model with Z2
symmetry, we verify the nontrivial non-Abelian statistics of Majorana fermions.
Numerical evidence and comparison in both Majorana-representation and
spin-representation are presented. The degenerate ground states of a symmetry
protected spin chain therefore previde a promising platform for topological
quantum computation.Comment: 5 pages,4 figure
Non-traditional CD4+CD25−CD69+ regulatory T cells are correlated to leukemia relapse after allogeneic hematopoietic stem cell transplantation
Background: Non-traditional CD4+CD25-CD69+ T cells were found to be involved in disease progression in tumor-bearing mouse models and cancer patients recently. We attempted to define whether this subset of T cells were related to leukemia relapse after allogeneic hematopoietic cell transplantation (allo-HSCT). Methods: The frequency of CD4+CD25-CD69+ T cells among the CD4+ T cell population from the bone marrow of relapsed patients, patients with positive minimal residual disease (MRD+) and healthy donors was examined by flow cytometry. The CD4+CD25-CD69+ T cells were also stained with the intracellular markers to determine the cytokine (TGF-beta, IL-2 and IL-10) secretion. Results: The results showed that the frequency of CD4+CD25-CD69 + T cells was markedly increased in patients in the relapsed group and the MRD + group compared to the healthy donor group. The percentage of this subset of T cells was significantly decreased after effective intervention treatment. We also analyzed the reconstitution of CD4+CD25-CD69+ T cells at various time points after allo-HSCT, and the results showed that this subset of T cells reconstituted rapidly and reached a relatively higher level at +60 d in patients compared to controls. The incidence of either MRD+ or relapse in patients with a high frequency of CD4+CD25-CD69+ T cells (>7%) was significantly higher than that of patients with a low frequency of CD4+CD25-CD69+ T cells at +60 d, +90 d and +270 d after transplant. However, our preliminary data indicated that CD4+CD25-CD69+ T cells may not exert immunoregulatory function via cytokine secretion. Conclusions: This study provides the first clinical evidence of a correlation between non-traditional CD4+CD25-CD69+ Tregs and leukemia relapse after allo-HSCT and suggests that exploration of new methods of adoptive immunotherapy may be beneficial. Further research related to regulatory mechanism behind this phenomenon would be necessary.Medicine, Research & ExperimentalSCI(E)[email protected]
Crystal engineered acid–base complexes with 2D and 3D hydrogen bonding systems using p-hydroxybenzoic acid as the building block
p-Hydroxybenzoic acid (p-HOBA) was selected as the building block for self-assembly with five bases, i.e., diethylamine, tert-butylamine, cyclohexylamine, imidazole and piperazine, and generation of the corresponding acid–base complexes 1–5. Crystal structure analyses suggest that proton-transfer from the carboxyl hydrogen to the nitrogen atom of the bases can be observed in 1–4, while only in 5 does a solvent water molecule co-exist with p--HOBA and piperazine. With the presence of O–H···O hydrogen bonds in 1–4, the deprotonated p-hydroxybenzoate anions (p-HOBAA–) are simply connected each other in a head-to-tail motif to form one-dimensional (1D) arrays, which are further extended to distinct two-dimensional (2D) (for 1 and 4) and three-dimensional (3D) (for 2 and 3) networks via N–H···O interactions. While in 5, neutral acid and base are combined pair-wise by O–H···N and N–H···O bonds to form a 1D tape and then the 1D tapes are sequentially combined by water molecules to create a 3D network. Some interlayer or intralayer C–H···O, C–H···p and p×××p interactions help to stabilize the supramolecular buildings. Melting point determination analyses indicate that the five acid–base complexes are not the ordinary superposition of the reactants and they are more stable than the original reactants
Research Progress on Synergistic Effect between Insulation Gas Mixtures
Synergetic effect is a special gas discharge phenomenon among insulating gas mixtures, which has important reference value for gas selection of future gas-insulated power equipment. The research progress and investigation methods of synergistic effect and insulation characteristics of different gas mixtures at home and abroad are reviewed in this chapter. The synergistic effect between different kinds of gas mixtures including SF6 gas mixtures and some new insulation gases such as c-C4F8, CF3I, and C4F7N is presented. Combined with the results of multiple studies, it can be seen that the synergistic effect of the gas mixture has a certain relationship with the electronic transport parameters and discharge patterns. Besides, the synergistic effect of the same gas mixture may change with the change of external conditions such as gas pressure, voltage type, and electrode distance
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