1,755 research outputs found
Dynamic admittance of atomic wires
We have investigated the low-frequency admittance of quantum wires in which a section consists of several Al atoms. The atomic section is connected to two three-dimensional leads that are modeled by the jellium model. The quantum scattering problem is solved by combining the first-principles ab initio method with a transfer-matrix evaluation of the scattering matrix. The ac admittance is then computed by evaluating various partial densities of states. The nature of the ac responses are predicted for these Al atomic wires.published_or_final_versio
Fibrosis-related growth factors in peritoneal dialysate during peritonitis
Session - Basic Research on Biocompatibility, Immunology, Inflammation, and Fibrosispublished_or_final_versio
A dual colour dual fusion fluorescence in situ hybridisation study on the genesis of complex variant translocations in chronic myelogenous leukaemia
Complex variant 9;22 translocations occur in a significant minority of chronic myelogenous leukaemia (CML) patients. Different mechanisms of their formation have been described. We report dual colour dual fusion fluorescence in situ hybridisation data in 12 Chinese CML patients with complex translocations. Three previously reported breakpoint hotspots in a third partner chromosome (14q32, 17q25, 1q2l) were observed. In 10/12 (83.3%) patients, the abnormality occurred as a single step 3-break event. Only a single abnormal clone harbouring the complex translocation was seen in this group. The remaining 2 cases in the chronic phase showed a 4-break mechanism (2/12,16.7%). Deletion of 5' ABL at der(9) was not observed in any of the 12 patients, however, the loss of 3' BCR was observed in 1 patient (1/12, 8.3%). Together with previous findings, these data suggest that these variant translocations occur more often as a 3-break single-step process with no reciprocal ABL-BCR fusion. On the other hand, a 4-break event is also regularly seen during the initial stages of leukaemogenesis, which likely predisposes to der(9) deletion. The observed difference in rates of der(9) deletion reported in a series of CML patients with variant translocations may be related to a difference in rates of a 4-break event.published_or_final_versio
Capacitance of Atomic Junctions
We report the behavior of the electrochemical capacitance for a variety of atomic junctions using ab initio methods. The capacitance can be classified according to the nature of conductance and shows a remarkable crossover from a quantum dominated regime to that of a classical-like geometric behavior. Clear anomalies arise due to a finite density of states of the atomic junction as well as the role played by the atomic valence orbitals. The results suggest several experiments to study contributions due to quantum effects and the atomic degree of freedom.published_or_final_versio
Quantum transport through atomic wires
We have investigated quantum transport through long wires in which a section consists of one or several Al atoms in a chain. The self-consistent ground state electronic potential is obtained using the first principles ab initio method and the conductance is calculated by solving a three-dimensional quantum scattering problem. We have observed quantized conductance when there are two or more Al atoms in the chain. Resistance is calculated for these wires at the Fermi level. ©1997 American Institute of Physics.published_or_final_versio
Structural and transport properties of aluminum atomic wires
We report a first-principles calculation of structural properties and quantum conductance of aluminum atomic wires. Our data together with a simple model allows us to predict the behavior of the elastic constant C11 as a function of the cross-sectional size of the free-standing wires. The quantum molecular dynamics, performed at both 0 and 300 K, provides information concerning the stability of these atomic wires. For the most stable wire, relaxation at 0 K causes a change of approximately 2-4 % in atomic positions, and room temperature contributes another 4–6 %. We obtain the quantum conductance of these wires by combining density functional theory and a three-dimensional evaluation of the scattering matrix. The structures obtained from the quantum molecular-dynamics simulations are examined and transport properties compared.published_or_final_versio
Identification of serum miR-139-3p as a non-invasive biomarker for colorectal cancer
Aberrant levels of circulating microRNAs are potential biomarkers for the early detection of colorectal cancer. The aim of this study was to study miR-139-3p and miR-622 in serum as a non-invasive biomarker for colorectal cancer diagnosis. We applied quantitative polymerase chain reaction to determine the levels of miR-139-3p and miR-622 in 42 pairs of tumor and adjacent non-tumor tissues, and in serum samples of 117 patients and 90 control subjects. Our results showed that miR-139-3p was silenced whereas miR-622 was overexpressed in colorectal cancer. Similarly, serum miR-139-3p level was significantly lower in colorectal cancer patients than in control subjects whereas miR-622 was more frequently detectable in patients. ROC analysis showed that AUC of miR-139-3p was 0.9935, with a sensitivity of 96.6% and specificity of 97.8%. Serum miR-139-3p level showed high sensitivity and specificity for both early and late stage CRCs and proximal and distal CRCs. Detectable serum miR-622 showed a sensitivity of 87.5% and specificity of 63.5% for discriminating CRC patients, but the sensitivity dropped for late stage patients (72.7%). We also included analyses of the blood CEA level for comparing the diagnostic performance of these blood-based biomarkers. The median level in CRC patients (3.6 ng/ml) was significantly higher than that in control (1.8 ng/ml). The AUC value of CEA in diagnosing CRC patients was 0.7515. CEA showed a positive correlation with tumor stage and age of patients and its level was higher in male. Collectively, serum miR-139-3p has strong potential as a promising non-invasive biomarker in colorectal cancer detection.published_or_final_versio
Identification of microRNA 885-5p as a novel regulator of tumor metastasis by targeting CPEB2 in colorectal cancer
published_or_final_versio
Spin-Rotation Symmetry Breaking in the Superconducting State of CuxBi2Se3
Spontaneous symmetry breaking is an important concept for understanding
physics ranging from the elementary particles to states of matter. For example,
the superconducting state breaks global gauge symmetry, and unconventional
superconductors can break additional symmetries. In particular, spin rotational
symmetry is expected to be broken in spin-triplet superconductors. However,
experimental evidence for such symmetry breaking has not been conclusively
obtained so far in any candidate compounds. Here, by 77Se nuclear magnetic
resonance measurements, we show that spin rotation symmetry is spontaneously
broken in the hexagonal plane of the electron-doped topological insulator
Cu0.3Bi2Se3 below the superconducting transition temperature Tc=3.4 K. Our
results not only establish spin-triplet superconductivity in this compound, but
may also serve to lay a foundation for the research of topological
superconductivity
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