Sequential Recommendation with Link-Prediction on Graphs Meta-Learning

Graduate School of Artificial IntelligenceIn this paper, we propose a novel framework called Sequential Graph Meta-learning (SGM) to address the problem of sequential recommendation, which involves predicting the next item based on a user???s historical behavior. SGM introduces a graph-based representation that captures the relationships between users and items, leveraging them as nodes and their interactions as edges. By extracting meaningful node embeddings, our model effectively encodes the complex relationships within the graph. Furthermore, we utilize subgraphs that represent user-item interactions with meta-learning, enabling the model to adapt and reflect as time change. Specifically, our approach focuses on link prediction, aiming to predict whether a user will interact with a specific item in the future. Through extensive experiments, we demonstrate that our SGM framework outperforms previous models in most scenarios by significant margins. This highlights the effectiveness of our proposed approach in addressing the challenges of sequential recommendation and enhancing recommendation accuracy.clos

Fracture behavior of brittle ceramics at the nanoscale

In spite of the excellent properties such as high hardness, low thermal expansion, enhanced resistance to chemical degradation and superior mechanical behavior at elevated temperature, ceramic materials usually suffer from the brittle fracture and catastrophic failure, which restrict them from being used for structural applications. While a number of researchers have strived to overcome this drawback of ceramic materials by constructing the microstructures that interfere with crack growth, recent theoretical and computational studies proposed another effective method to suppress the rapid crack propagation by reducing the specimen size down to the nanometer scale. In this study, we investigated the mechanical properties of brittle ceramics by changing sample sizes from bulk to nanoscale with particular focus on their fracture failure. For the ease of analysis, we chose the isotropic, homogeneous and purely brittle material, i.e., diamond-like carbon. In-situ fixed-ends bending experiments were conducted with different beam thicknesses and lengths, 1μm ~ 100nm and 3μm ~ 6μm, respectively. Additionally, in order to demonstrate the feasibility to intactly transfer the superior properties emergent only at the nanoscale to the macroscopically available form, we fabricated the large-area 3D hierarchical hollow ceramic nano-architectures using proximity nano-patterning technique

Cucurbit[7]uril aggregates in the gas phase investigated by ion mobility-mass spectrometry

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Eutectic Formation of Naproxen with Some Dicarboxylic Acids

Eutectic formation with additives is one of the established methods to improve the dissolution behaviors of active pharmaceutic ingredients (APIs). The improvement is mainly due to the increase in the surface area for dissolution, which originates from the finely divided micro-domains generated through the phase separation of the miscible liquid components upon solidification. The present study is to identify eutectic-forming additives for naproxen (NPX), a class II API of the biopharmaceutical classification system. A particular aim was to develop a eutectic mixture with NPX at least over 20 wt%, a minimum to be practical for oral delivery. Screening based on the proximity of the solubility parameter values identified dicarboxylic acids (succinic acid, glutaric acid, and suberic acid) as desirable additives for NPX. Binary melting diagrams were constructed to confirm the eutectic compositions, and the eutectic mixture with suberic acid (NPX 55 wt%) was further investigated. The dissolution (at pH 5.0) of the melt crystallized eutectics was enhanced compared to the simple physical mixture of the same compositions and neat NPX, which was attributed to the microscopically observed lamellar structures. The current study should support the systematic investigations of API eutectic mixtures by selecting appropriate eutectic-forming additives

Trapping Alkali Metal-Halide Cluster Ions in the Cucurbit[n]uril Cavity Investigated by Ion Mobility-Mass Spectrometry

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Trapping Alkali Halide Cluster Ions in the Cucurbit[n]uril During the Solvent Evaporation

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Visible-Light-Induced Organophotocatalytic Difunctionallization: Open-Air Hydroxysulfurization of Aryl Alkenes with Aryl Thiols

© 2022 American Chemical Society. All rights reserved.Herein, we report a regioselective visible-light-induced organophotoredox catalytic difunctionalization method to prepare β-hydroxysulfides using aryl alkenes and aryl thiols as substrates. The reaction provides a wide substrate scope of aryl alkenes (from simple styrene to complex bioactive compounds) and aryl thiols (from diverse heteroaromatic thiols to nonheteroaromatic thiols) (total 45 examples, up to 88% yield). Based on the combined experimental and computational studies, we demonstrate that in situ generated hydroperoxyl radicals from O2 in air react with benzylic radicals, which restrains the reaction between benzylic radicals and the acidic form of thiols in a classical thiol-ene radical reaction. We show that difunctionalization is possible due to the choice of bases, diluted substrate concentrations, increment in catalyst loading, and selection of suitable aryl thiols under aerobic conditions. Considering the biological importance of heteroaromatic thiols and the lack of methods to install them, our approach offers a platform to derive various β-hydroxysulfides that contain aromatic elements.11Nsciescopu

Stereoselective construction of sterically hindered oxaspirocycles: Via chiral bidentate directing group-mediated C(sp3)-O bond formation

The systematic investigation of chiral bidentate auxiliaries has resulted in the discovery of a chiral 2,2-dimethyl-1-(pyridin-2-yl)propan-1-amine-derived directing group that enables stereoselective palladium(ii)-catalyzed intramolecular C(sp3)-O bond formation. This new chiral directing group exhibited high reactivity in the activation of methylene C(sp3)-H bonds with excellent levels of stereoselectivity (a diastereomeric ratio of up to 39:::1), which allowed the construction of a wide range of oxaspirocycles. Mechanistic investigations were also conducted to elucidate the reaction mechanism and understand the origin of the diastereoselectivity. DFT calculations suggest that only modest levels of diastereoselectivity are accomplished at the rate-determining C-H metalation-deprotonation step and the d.r. is further enriched at the reductive elimination step. © 2018 The Royal Society of Chemistry11sciescopu