2,228 research outputs found
A constrained clustering approach to duplicate detection among relational data
This paper proposes an approach to detect duplicates among relational data. Traditional methods for record linkage or duplicate detection work on a set of records which have no explicit relations with each other. These records can be formatted into a single database table for processing. However, there are situations that records from different sources can not be flattened into one table and records within one source have certain (semantic) relations between them. The duplicate detection issue of these relational data records/instances can be dealt with by formatting them into several tables and applying traditional methods to each table. However, as the relations among the original data records are ignored, this approach generates poor or inconsistent results. This paper analyzes the characteristics of relational data and proposes a particular clustering approach to perform duplicate detection. This approach incorporates constraint rules derived from the characteristics of relational data and therefore yields better and more consistent results, which are revealed by our experiments. © Springer-Verlag Berlin Heidelberg 2007
Gravity waves over topographical bottoms: Comparison with the experiment
In this paper, the propagation of water surface waves over one-dimensional
periodic and random bottoms is investigated by the transfer matrix method. For
the periodic bottoms, the band structure is calculated, and the results are
compared to the transmission results. When the bottoms are randomized, the
Anderson localization phenomenon is observed. The theory has been applied to an
existing experiment (Belzons, et al., J. Fluid Mech. {\bf 186}, 530 (1988)). In
general, the results are compared favorably with the experimental observation.Comment: 15 pages, 7 figure
Using malware for software-defined networking–based smart home security management through a taint checking approach
Electrical Switching of the Edge Current Chirality in Quantum Anomalous Hall Insulators
A quantum anomalous Hall (QAH) insulator is a topological state of matter, in
which the interior is insulating but electrical current flows along the edges
of the sample, in either clockwise (right-handed) or counter-clockwise
(left-handed) direction dictated by the spontaneous magnetization orientation.
Such chiral edge current (CEC) eliminates any backscattering, giving rise to
quantized Hall resistance and zero longitudinal resistance. In this work, we
fabricate mesoscopic QAH sandwich (i.e. magnetic topological insulator
(TI)/TI/magnetic TI) Hall bar devices and succeed in switching the CEC
chirality in QAH insulators through spin-orbit torque (SOT) by applying a
current pulse and suitably controlled gate voltage. The well-quantized QAH
states with opposite CEC chiralities are demonstrated through four- and
three-terminal measurements before and after SOT switching. Our theoretical
calculations show that the SOT that enables the magnetization switching can be
generated by both bulk and surface carriers in QAH insulators, in good
agreement with experimental observations. Current pulse-induced switching of
the CEC chirality in QAH insulators will not only advance our knowledge in the
interplay between magnetism and topological states but also expedite easy and
instantaneous manipulation of the QAH state in proof-of-concept
energy-efficient electronic and spintronic devices as well as quantum
information applications.Comment: 24 pages, 5 figures, comments are welcom
Serum-free medium for long-term growth, freezing, cloning and fusion of myelomas and hybridomas.
Even-Odd Layer-Dependent Anomalous Hall Effect in Topological Magnet MnBi2Te4 Thin Films
A central theme in condensed matter physics is to create and understand the
exotic states of matter by incorporating magnetism into topological materials.
One prime example is the quantum anomalous Hall (QAH) state. Recently, MnBi2Te4
has been demonstrated to be an intrinsic magnetic topological insulator and the
QAH effect was observed in exfoliated MnBi2Te4 flakes. Here, we used molecular
beam epitaxy (MBE) to grow MnBi2Te4 films with thickness down to 1 septuple
layer (SL) and performed thickness-dependent transport measurements. We
observed a non-square hysteresis loop in the antiferromagnetic state for films
with thickness greater than 2 SL. The hysteresis loop can be separated into two
AH components. Through careful analysis, we demonstrated that one AH component
with the larger coercive field is from the dominant MnBi2Te4 phase, while the
other AH component with the smaller coercive field is from the minor Mn-doped
Bi2Te3 phase in the samples. The extracted AH component of the MnBi2Te4 phase
shows a clear even-odd layer-dependent behavior, a signature of
antiferromagnetic thin films. Our studies reveal insights on how to optimize
the MBE growth conditions to improve the quality of MnBi2Te4 films, in which
the QAH and other exotic states are predicted.Comment: 23 pages, 4 figures, comments are welcom
Hypermethylation of the TGF-β target, ABCA1 is associated with poor prognosis in ovarian cancer patients
Background
The dysregulation of transforming growth factor-β (TGF-β) signaling plays a crucial role in ovarian carcinogenesis and in maintaining cancer stem cell properties. Classified as a member of the ATP-binding cassette (ABC) family, ABCA1 was previously identified by methylated DNA immunoprecipitation microarray (mDIP-Chip) to be methylated in ovarian cancer cell lines, A2780 and CP70. By microarray, it was also found to be upregulated in immortalized ovarian surface epithelial (IOSE) cells following TGF-β treatment. Thus, we hypothesized that ABCA1 may be involved in ovarian cancer and its initiation.
Results
We first compared the expression level of ABCA1 in IOSE cells and a panel of ovarian cancer cell lines and found that ABCA1 was expressed in HeyC2, SKOV3, MCP3, and MCP2 ovarian cancer cell lines but downregulated in A2780 and CP70 ovarian cancer cell lines. The reduced expression of ABCA1 in A2780 and CP70 cells was associated with promoter hypermethylation, as demonstrated by bisulfite pyro-sequencing. We also found that knockdown of ABCA1 increased the cholesterol level and promoted cell growth in vitro and in vivo. Further analysis of ABCA1 methylation in 76 ovarian cancer patient samples demonstrated that patients with higher ABCA1 methylation are associated with high stage (P = 0.0131) and grade (P = 0.0137). Kaplan-Meier analysis also found that patients with higher levels of methylation of ABCA1 have shorter overall survival (P = 0.019). Furthermore, tissue microarray using 55 ovarian cancer patient samples revealed that patients with a lower level of ABCA1 expression are associated with shorter progress-free survival (P = 0.038).
Conclusions
ABCA1 may be a tumor suppressor and is hypermethylated in a subset of ovarian cancer patients. Hypermethylation of ABCA1 is associated with poor prognosis in these patients
Cardiovascular and renal outcomes with canagliflozin according to baseline diuretic use:a post hoc analysis from the CANVAS Program
Aims The CANVAS Program identified the effect of canagliflozin on major adverse cardiovascular events (MACE) differed according to whether participants were using diuretics at study commencement. We sought to further evaluate this finding related to baseline differences, treatment effects, safety, and risk factor changes.Methods and results The CANVAS Program enrolled 10 142 participants with type 2 diabetes mellitus and high cardiovascular risk. Participants were randomized to canagliflozin or placebo and followed for a mean of 188 weeks. The primary outcome was major cardiovascular events, a composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. Secondary outcomes included multiple cardiovascular, renal, and safety events. In this post hoc subgroup analysis, participants were categorized according to baseline use of any diuretic. The effect on outcomes was compared using Cox proportional hazards models, while risk factor changes were compared using mixed-effect models. At baseline, 4490 (44.3%) participants were using a diuretic. Compared with those not using a diuretic, participants using a diuretic were more likely to be older (mean age +/- standard deviation, 64.3 +/- 8.0 vs. 62.5 +/- 8.3), be female (38.9% vs. 33.4%), and have heart failure (19.6% vs. 10.3%) (all P-difference < 0.0001). The effect of canagliflozin on major cardiovascular events was greater for those using diuretic at baseline than for those who were not [adjusted hazard ratio 0.65 (95% confidence interval 0.54-0.78) vs. adjusted hazard ratio 1.13 (95% confidence interval 0.93-1.36), P-heterogeneity < 0.0001]. Changes in most risk factors, including blood pressure, body weight, and urine albumin-to-creatinine ratio, were similar between groups (all P-difference > 0.11), although the effect of canagliflozin on haemoglobin A1c reduction was slightly weaker in participants using compared with not using diuretics at baseline (-0.52% vs. -0.64%, P-heterogeneity = 0.0007). Overall serious adverse events and key safety outcomes, including adverse renal events, were also similar (all P-heterogeneity > 0.07).Conclusions Participants on baseline diuretics derived a greater benefit for major cardiovascular events from canagliflozin, which was not fully explained by differences in participant characteristics nor risk factor changes.</p
High pressure study on LaFeAsO with different Tc
We report studies on pressure dependence of superconducting transition
temperature (Tc) of LaFeAsO, LaFeAs(O0.5F0.5) and LaFeAs(O0.89F0.11) samples.
In-situ resistance measurements under high pressure showed that the Tc of these
three compounds increases with pressure initially, reaches a maximum value and
then decreases with further increasing pressure, although the Tc at ambient
pressure are different. The onset Tc of LaFeAsO is ~50 K at 1.5 GPa, which is
the highest record in La-based oxypnicited system. The significant change in Tc
induced by pressure is attributed to the orbital degeneracy and the electron
density of state at the Fermi level.Comment: 13 pages, 4 figure
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