25 research outputs found
Interpretable Sequence Clustering
Categorical sequence clustering plays a crucial role in various fields, but
the lack of interpretability in cluster assignments poses significant
challenges. Sequences inherently lack explicit features, and existing sequence
clustering algorithms heavily rely on complex representations, making it
difficult to explain their results. To address this issue, we propose a method
called Interpretable Sequence Clustering Tree (ISCT), which combines sequential
patterns with a concise and interpretable tree structure. ISCT leverages k-1
patterns to generate k leaf nodes, corresponding to k clusters, which provides
an intuitive explanation on how each cluster is formed. More precisely, ISCT
first projects sequences into random subspaces and then utilizes the k-means
algorithm to obtain high-quality initial cluster assignments. Subsequently, it
constructs a pattern-based decision tree using a boosting-based construction
strategy in which sequences are re-projected and re-clustered at each node
before mining the top-1 discriminative splitting pattern. Experimental results
on 14 real-world data sets demonstrate that our proposed method provides an
interpretable tree structure while delivering fast and accurate cluster
assignments.Comment: 11 pages, 6 figure
Experimental realization of chiral Landau levels in two-dimensional Dirac cone systems with inhomogeneous effective mass
Chiral zeroth Landau levels are topologically protected bulk states that give
rise to chiral anomaly. Previous discussions on such chiral Landau levels are
based on three-dimensional Weyl degeneracies. Their realizations using
two-dimensional Dirac point systems, being more promising for future
applications, were never reported before. Here we propose a theoretical and
experimental scheme for realizing chiral Landau levels in a photonic system. By
introducing an inhomogeneous effective mass through breaking local parity
inversion symmetries, the zeroth-order chiral Landau levels with one-way
propagation characteristics are experimentally observed. In addition, the
robust transport of the chiral zeroth mode against defects in the system is
experimentally tested. Our system provides a new pathway for the realization of
chiral Landau levels in two-dimensional Dirac systems, and may potentially be
applied in device designs utilizing the transport robustness
Experimental demonstration of non-adjacent band topology connecting multiple nodal links
Nodal links are special configurations of band degeneracies in the momentum
space, where nodal line branches encircle each other. In PT symmetric systems,
nodal lines can be topologically characterized using the eigenvector frame
rotations along an encircling loop and the linking structure can be described
with non-Abelian frame charges interacting among adjacent bands. In this paper,
we present a photonic multiple nodal links system, where non-adjacent band
topology is proposed to characterize the hidden relation between nodal lines
from non-adjacent band pairs. Through an orthogonal nodal chain, the nodal line
from the lower two bands predicts the existence of nodal lines formed between
the higher bands. We designed and fabricated a metamaterial, with which the
multiple nodal links and non-adjacent band topology are experimentally
demonstrated
Experimental observation of non-Abelian earring nodal links in phononic crystals
Nodal lines are symmetry-protected one-dimensional band degeneracies in
momentum space, which can appear in numerous topological configurations such as
nodal rings, chains, links, and knots. Very recently, non-Abelian topological
physics has been proposed in space-time inversion (PT) symmetric systems, and
attract widespread attention. One of the most special configurations in
non-Abelian system is the earring nodal link, composing of a nodal chain
linking with an isolated nodal line, is signature of non-Abelian topology and
cannot be elucidated using Abelian topological classifications. However, the
earring nodal links have not been yet observed in real system. Here we design
the phononic crystals with earring nodal links, and verify its non-Abelian
topologicial charge in full-wave simulations. Moreover, we experimentally
observed two different kinds of earring nodal links by measuring the band
structures for two phononic crystals. Specifically, we found that the order of
the nodal chain and line can switch after band inversion but their link cannot
be severed. Our work provides experimental evidence for phenomena unique to
non-Abelian band topology and our simple acoustic system provides a convenient
platform for studying non-Abelian charges.Comment: 14 pages, 3 figure
Synthesis, structural and chemosensitivity studies of arena d6 metal complexes having N-phenyl-N'-(pyridyl/pyrimidyl) thiourea derivatives
The d6 metal complexes of thiourea derivatives were synthesized to investigate its cytotoxicity. Treatment of various N‐phenyl‐N ́ pyridyl/pyrimidyl thiourea ligands with half‐sandwich d6 metal precursors yielded a series of cationic com- plexes. Reactions of ligand (L1‐L3) with [(p‐cymene)RuCl2]2 and [Cp*MCl2]2 (M = Rh/Ir) led to the formation of a series of cationic complexes bearing gen- eral formula [(arene)M(L1)к2(N,S)Cl]+, [(arene)M(L2)к2(N,S)Cl]+ and [(arene) M(L3)к2(N,S)Cl]+ [arene = p‐cymene, M = Ru (1, 4, 7); Cp*, M = Rh (2, 5, 8); Cp*, Ir (3, 6, 9)]. These compounds were isolated as their chloride salts. X‐ray crystallographic studies of the complexes revealed the coordination of the ligands to the metal in a bidentate chelating N,S‐ manner. Further the cytotox- icity studies of the thiourea derivatives and its complexes evaluated against HCT‐116 (human colorectal cancer), MIA‐PaCa‐2 (human pancreatic cancer) and ARPE‐19 (non‐cancer retinal epithelium) cancer cell lines showed that the thiourea ligands displayed no activity. Upon complexation however, the metal compounds possesses cytotoxicity and whilst potency is less than cisplatin, several complexes exhibited greater selectivity for HCT‐116 or MIA‐ PaCa‐2 cells compared to ARPE‐19 cells than cisplatin in vitro. Rhodium complexes of thiourea derivatives were found to be more potent as compared to ruthenium and iridium complexes.<br/
Quantum Cognitive Modeling: New Applications and Systems Research Directions
Expanding the benefits of quantum computing to new domains remains a
challenging task. Quantum applications are concentrated in only a few domains,
and driven by these few, the quantum stack is limited in supporting the
development or execution demands of new applications. In this work, we address
this problem by identifying both a new application domain, and new directions
to shape the quantum stack. We introduce computational cognitive models as a
new class of quantum applications. Such models have been crucial in
understanding and replicating human intelligence, and our work connects them
with quantum computing for the first time. Next, we analyze these applications
to make the case for redesigning the quantum stack for programmability and
better performance. Among the research opportunities we uncover, we study two
simple ideas of quantum cloud scheduling using data from gate-based and
annealing-based quantum computers. On the respective systems, these ideas can
enable parallel execution, and improve throughput. Our work is a contribution
towards realizing versatile quantum systems that can broaden the impact of
quantum computing on science and society
MicroRNA-1 Regulates the Differentiation of Adipose-Derived Stem Cells into Cardiomyocyte-Like Cells
Stem cell transplantation is one of most valuable methods in the treatment of myocardial infarction, and adipose-derived stem cells (ASCs) are becoming a hot topic in medical research. Previous studies have shown that ASCs can be differentiated into cardiomyocyte-like cells, but the efficiency and survival rates are low. We investigated the role and mechanism of microRNA-1 (miR-1) in the differentiation of ASCs into cardiomyocyte-like cells. ASCs and cardiomyocytes were isolated from neonatal rats. We constructed lentivirus for overexpressing miR-1 and used DAPT, an antagonist of the Notch1 pathway, for in vitro analyses. We performed cocultures with ASCs and cardiomyocytes. The differentiation efficiency of ASCs was detected by cell-specific surface antigens. Our results showed that miR-1 can promote the expression of Notch1 and reduce the expression of Hes1, a Notch pathway factor, and overexpression of miR-1 can promote the differentiation of ASCs into cardiomyocyte-like cells, which may occur by regulating Notch1 and Hes1