4,297 research outputs found
3-(2-AminoÂethyl)-2-(4-chloroÂanilino)Âquinazolin-4(3H)-one methanol 0.75-solvate
In the asymmetric unit of the title compound, C16H15ClN4O·0.75CH3OH, there are two independent quinazolin-4(3H)-one molÂecules and one and a half methanol molÂecules. One of the methanol molÂecules is disordered over two positions with equal occupancies. The dihedral angles between the quinazoline ring system and the chloroÂbenzene ring in the two quinazolin-4(3H)-one molÂecules are essentially the same, at 39.83 (1) and 39.84 (1)°. IntraÂmolecular N—H⋯N and O—H⋯O, and interÂmolecular N—H⋯O and N—H⋯N hydrogen bonds are observed. In addition, π–π stacking interÂactions, with centroid-to-centroid distances of 3.654 (1), 3.766 (1) and 3.767 (1) Å, and weak C—H⋯π interÂactions, are observed
E17110 promotes reverse cholesterol transport with liver X receptor β agonist activity in vitro
AbstractLiver X receptor (LXR) plays an important role in reverse cholesterol transport (RCT), and activation of LXR could reduce atherosclerosis. In the present study we used a cell-based screening method to identify new potential LXRβ agonists. A novel benzofuran-2-carboxylate derivative was identified with LXRβ agonist activity: E17110 showed a significant activation effect on LXRβ with an EC50 value of 0.72μmol/L. E17110 also increased the expression of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) in RAW264.7 macrophages. Moreover, E17110 significantly reduced cellular lipid accumulation and promoted cholesterol efflux in RAW264.7 macrophages. Interestingly, we found that the key amino acids in the LXRβ ligand-binding domain had distinct interactions with E17110 as compared to TO901317. These results suggest that E17110 was identified as a novel compound with LXRβ agonist activity in vitro via screening, and could be developed as a potential anti-atherosclerotic lead compound
Realization of Two-Dimensional Spin-orbit Coupling for Bose-Einstein Condensates
Cold atoms with laser-induced spin-orbit (SO) interactions provide intriguing
new platforms to explore novel quantum physics beyond natural conditions of
solids. Recent experiments demonstrated the one-dimensional (1D) SO coupling
for boson and fermion gases. However, realization of 2D SO interaction, a much
more important task, remains very challenging. Here we propose and
experimentally realize, for the first time, 2D SO coupling and topological band
with Rb degenerate gas through a minimal optical Raman lattice scheme,
without relying on phase locking or fine tuning of optical potentials. A
controllable crossover between 2D and 1D SO couplings is studied, and the SO
effects and nontrivial band topology are observed by measuring the atomic cloud
distribution and spin texture in the momentum space. Our realization of 2D SO
coupling with advantages of small heating and topological stability opens a
broad avenue in cold atoms to study exotic quantum phases, including the
highly-sought-after topological superfluid phases.Comment: 27 pages, 5 figure
Preparation and Properties of Fe3O4 Biomimetic Micro-nano Structure Coatings
Nanoparticles filling is one of the most effective methods to build the micro-nano structure. In this paper, the composite coatings containing Fe3O4 nanoparticles were prepared from fluorinated silicon polymer by in-situ polymerization. FT-IR was used to characterize the structure of the composite material. SEM and AFM were performed to observe the microstructure of the coatings. The contact angle of water and coatings was tested. The results showed that the biomimetic micro-nano structure of the coatings, which formed on the glass plate, was exactly familiar with that of the surface of lotus leaves. Keyword: micro-nano structure; Fe3O4 nanoparticles; in-situ polymerization; biomimeti
Demonstration of Adiabatic Variational Quantum Computing with a Superconducting Quantum Coprocessor
Adiabatic quantum computing enables the preparation of many-body ground
states. This is key for applications in chemistry, materials science, and
beyond. Realisation poses major experimental challenges: Direct analog
implementation requires complex Hamiltonian engineering, while the digitised
version needs deep quantum gate circuits. To bypass these obstacles, we suggest
an adiabatic variational hybrid algorithm, which employs short quantum circuits
and provides a systematic quantum adiabatic optimisation of the circuit
parameters. The quantum adiabatic theorem promises not only the ground state
but also that the excited eigenstates can be found. We report the first
experimental demonstration that many-body eigenstates can be efficiently
prepared by an adiabatic variational algorithm assisted with a multi-qubit
superconducting coprocessor. We track the real-time evolution of the ground and
exited states of transverse-field Ising spins with a fidelity up that can reach
about 99%.Comment: 12 pages, 4 figure
Reward Imputation with Sketching for Contextual Batched Bandits
Contextual batched bandit (CBB) is a setting where a batch of rewards is
observed from the environment at the end of each episode, but the rewards of
the non-executed actions are unobserved, resulting in partial-information
feedback. Existing approaches for CBB often ignore the rewards of the
non-executed actions, leading to underutilization of feedback information. In
this paper, we propose an efficient approach called Sketched Policy Updating
with Imputed Rewards (SPUIR) that completes the unobserved rewards using
sketching, which approximates the full-information feedbacks. We formulate
reward imputation as an imputation regularized ridge regression problem that
captures the feedback mechanisms of both executed and non-executed actions. To
reduce time complexity, we solve the regression problem using randomized
sketching. We prove that our approach achieves an instantaneous regret with
controllable bias and smaller variance than approaches without reward
imputation. Furthermore, our approach enjoys a sublinear regret bound against
the optimal policy. We also present two extensions, a rate-scheduled version
and a version for nonlinear rewards, making our approach more practical.
Experimental results show that SPUIR outperforms state-of-the-art baselines on
synthetic, public benchmark, and real-world datasets.Comment: Accepted by NeurIPS 202
Generative Retrieval with Semantic Tree-Structured Item Identifiers via Contrastive Learning
The retrieval phase is a vital component in recommendation systems, requiring
the model to be effective and efficient. Recently, generative retrieval has
become an emerging paradigm for document retrieval, showing notable
performance. These methods enjoy merits like being end-to-end differentiable,
suggesting their viability in recommendation. However, these methods fall short
in efficiency and effectiveness for large-scale recommendations. To obtain
efficiency and effectiveness, this paper introduces a generative retrieval
framework, namely SEATER, which learns SEmAntic Tree-structured item
identifiERs via contrastive learning. Specifically, we employ an
encoder-decoder model to extract user interests from historical behaviors and
retrieve candidates via tree-structured item identifiers. SEATER devises a
balanced k-ary tree structure of item identifiers, allocating semantic space to
each token individually. This strategy maintains semantic consistency within
the same level, while distinct levels correlate to varying semantic
granularities. This structure also maintains consistent and fast inference
speed for all items. Considering the tree structure, SEATER learns identifier
tokens' semantics, hierarchical relationships, and inter-token dependencies. To
achieve this, we incorporate two contrastive learning tasks with the generation
task to optimize both the model and identifiers. The infoNCE loss aligns the
token embeddings based on their hierarchical positions. The triplet loss ranks
similar identifiers in desired orders. In this way, SEATER achieves both
efficiency and effectiveness. Extensive experiments on three public datasets
and an industrial dataset have demonstrated that SEATER outperforms
state-of-the-art models significantly.Comment: 8 main pages, 3 pages for appendi
Observation of quantum fingerprinting beating the classical limit
Quantum communication has historically been at the forefront of advancements,
from fundamental tests of quantum physics to utilizing the quantum-mechanical
properties of physical systems for practical applications. In the field of
communication complexity, quantum communication allows the advantage of an
exponential reduction in the information transmitted over classical
communication to accomplish distributed computational tasks. However, to date,
demonstrating this advantage in a practical setting continues to be a central
challenge. Here, we report an experimental demonstration of a quantum
fingerprinting protocol that for the first time surpasses the ultimate
classical limit to transmitted information. Ultra-low noise superconducting
single-photon detectors and a stable fibre-based Sagnac interferometer are used
to implement a quantum fingerprinting system that is capable of transmitting
less information than the classical proven lower bound over 20 km standard
telecom fibre for input sizes of up to two Gbits. The results pave the way for
experimentally exploring the advanced features of quantum communication and
open a new window of opportunity for research in communication complexity and
testing the foundations of physics.Comment: 19 pages, 4 figure
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