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The contradiction between the large population of China and the limited medical resources lead to the difficulty of getting medical services. The emergence of question answering (QA) system in the medical field allows people to receive timely treatment at home and alleviates the burden on hospitals and doctors. To this end, this paper proposes a new model called Att-BiRNN-Att which combines the Bidirectional RNN (Recurrent Neural Network) with two attention mechanisms. The model employs BiRNN to capture more information in the context instead of the traditional directional RNN. Also, two attention mechanisms are used in the model to produce better feature representation of the answer. One attention is used before the input of BiRNN, and the other is used after the output of BiRNN. The combination of two attentions makes full use of the relevant information between the answer and question. The experiment on the HealthTap medical QA dataset shows that our model outperforms four state-of-theart deep learning models, which confirm the effectiveness of Att-BiRNN-Att model.

Photochemical dearomative cycloaddition has emerged as a useful strategy to rapidly generate molecular complexity. Within this context, stereo- and regiocontrolled intermolecular para-cycloadditions are rare. Herein, a method to achieve photochemical cycloaddition of quinolines and alkenes is shown. Emphasis is placed on generating sterically congested products and reaction of highly substituted alkenes and allenes. In addition, the mechanistic details of the process are studied, which revealed a reversible radical addition and a selectivity-determining radical recombination. The regio- and stereochemical outcome of the reaction is also rationalized.

Dearomative cycloaddition reactions represent an ideal means of converting flat arenes into three-dimensional architectures of increasing interest in medicinal chemistry. Quinolines, isoquinolines, and quinazolines, despite containing latent diene and alkene subunits, are scarcely applied in cycloaddition reactions because of the inherent low reactivity of aromatic systems and selectivity challenges. Here, we disclose an energy transfer-mediated, highly regio- and diastereoselective intermolecular [4 + 2] dearomative cycloaddition reaction of these bicyclic azaarenes with a plethora of electronically diverse alkenes. This approach bypasses the general reactivity and selectivity issues, thereby providing various bridged polycycles that previously have been inaccessible or required elaborate synthetic efforts. Computational studies with density functional theory elucidate the mechanism and origins of the observed regio- and diastereoselectivities.

Controlling triplet states is crucial to improve the efficiency and lifetime of organic room temperature phosphorescence (ORTP). Although the intrinsic factors from intramolecular radiative and non-radiative decay have been intensively investigated, the extrinsic factors that affect triplet exciton quenching are rarely reported. Diffusion to the defect sites inside the crystal or at the crystal surface may bring about quenching of triplet exciton. Here, the phosphorescence lifetime is found to have a negative correlation with the triplet exciton diffusion coefficient based on the density functional theory (DFT)/time-dependent density functional theory (TD-DFT) calculations on a series of ORTP materials. For systems with a weak charge transfer (CT) characteristic, close π–π stacking will lead to strong triplet coupling and fast triplet exciton diffusion in most cases, which is detrimental to the phosphorescence lifetime. Notably, for intramolcular donor–acceptor (D–A) type systems with a CT characteristic, intermolecular D–A stacking results in ultra-small triplet coupling, thus contributing to slow triplet diffusion and long phosphorescence lifetime. These findings shed some light on molecular design toward high-efficiency long persistent ORTP. [ABSTRACT FROM AUTHOR]

Vegetation Water Content (VWC) and Soil Moisture (SM) are closely related. To overcome the limitations of the Global Navigation Satellite System Interferometry Reflectometry (GNSS-IR) for point-based monitoring, this research aimed at developing a synchronous retrieval method for VWC and SM by integrating GNSS-IR and multi-source data. The method incorporates band synthesis, optimized modelling, and a Stacking algorithm. The model produced Normalized Microwave Reflectance Index (NMRI) and SM products consistent with MODIS NDVI, LAI, and NASA-USDA SM data in both time and space. The study provides a novel approach for the synchronous retrieval of VWC and SM and facilitates in-depth exploration of their interaction mechanisms. [ABSTRACT FROM AUTHOR]