The first enantioselective aza‐Darzens reaction of cyclic imines with α‐halogenated ketones was realized under mild reaction conditions by using amino‐acid‐derived bifunctional phosphonium salts as ...phase‐transfer promoters. A variety of structurally dense tri‐ and tetrasubstituted aziridine derivatives, containing benzofused heterocycles as well as spiro‐structures, were readily synthesized in high yields with excellent diastereo‐ and enantioselectivities (up to >20:1 d.r. and >99.9 % ee). The highly functionalized aziridine products could be easily transformed into different classes of biologically active compounds.
Pinch of salt: A highly enantioselective aza‐Darzens cyclization between cyclic imines and α‐halogenated ketones catalyzed by amino‐acid‐derived bifunctional phosphonium salts has been developed. A wide range of enantioenriched fused tri‐ and tetrasubstituted aziridines were synthesized with high yields and excellent diastereo‐ and enantioselectivities. Scale‐up synthesis and valuable transformations are also demonstrated.
Abstract
We present a generic study on the information-theoretic security of multi-setting device-independent quantum key distribution (DIQKD) protocols, i.e. ones that involve more than two ...measurements (or inputs) for each party to perform, and yield dichotomic results (or outputs). The approach we develop, when applied in protocols with either symmetric or asymmetric Bell experiments, yields nontrivial upper bounds on the secure key rates, along with the detection efficiencies required upon the measuring devices. The results imply that increasing the number of measurements may lower the detection efficiency required by the security criterion. The improvement, however, depends on (i) the choice of multi-setting Bell inequalities chosen to be tested in a protocol, and (ii) either a symmetric or asymmetric Bell experiment is considered. Our results serve as an advance toward the quest for evaluating security and reducing efficiency requirement of applying DIQKD in scenarios without heralding.
The coupling framework of modern literary works and traditional culture is first discussed in this paper, and the intrinsic connection between them is examined. Secondly, a semantic-associated ...information extraction network model is constructed using LSTM and attention mechanism, and the target semantic fusion is achieved through semantic space conversion and semantic-associated information extraction. Finally, the dataset and empirical analysis confirm the SAIEDMMA model’s effectiveness. The results show that the F1 value of the SAIE-DMMA model on the Total-Text dataset and ICDAR2015 dataset is 85.59% and 87.72%, respectively. The traditional culture of folk culture has the highest degree of integration in modern literature, and the growth of its literature from 2017 to 2021 is 1,273 books. This shows that the semantic correlation information extraction network can analyze the semantics of the integration of modern literary works and traditional culture, and it can also be used to promote the effective inheritance and development of traditional culture so that modern literary works are closer to public life.
In this paper, the characteristic parameters with different properties are transformed into comprehensive quantified values, the deviation of characteristic parameters is defined using the interval ...number variable weight principle, and the teaching situation is created by combining students’ interests. The weight vector is derived from the disappointment function to assess the humanistic quality of Chinese language and literature education. Let the state vector be mapped by a variable-weight mapping, which will monotonically increase or decrease each variable continuum, reflecting the first-order change in Chinese language students' learning status. It is found that 18.66% of the first-year students in colleges and universities are familiar with humanistic quality, and the highest real-time rate is 0.9906. The principle of variable weight based on interval numbers can be used to effectively cultivate students' humanistic qualities and develop high-quality and innovative talents.
Abstract
Given a communication system using quantum key distribution (QKD), the receiver can be seen as one who tries to guess the sender’s information just as potential eavesdroppers do. The ...receiver-eavesdropper similarity thus implies a simple relation in terms of guessing probability and correctness of sifted keys, related with the distance-based, information-theoretic security. The tolerable regions of error rates determined by such a guessing-probability-based relation are shown to be close to those determined by security criteria. Thus, an alternative perspective on applying guessing probability in analyzing QKD issues is here provided. Examples of two specific protocols are illustrated. Our results contribute to evaluating an important element in communication study, and may provide useful reference for the security analysis of QKD protocols.
A mild, efficient, convenient and scalable method to synthesize phosphinates via direct phosphorylation between R2P(O)H and ROH was developed. All aromatic substrates completed this transformation ...with excellent yields (up to 98 %), and preliminary mechanistic studies suggest that a carbene‐involving process from CHCl3 to CH2Cl2 facilitates the phosphorylation.
A mild, efficient, convenient, and scalable method to synthesize phosphinates via direct phosphorylation between R2P(O)H and ROH was developed. Preliminary mechanistic studies suggest that a carbene‐involving process from CHCl3 to CH2Cl2 facilitates the phosphorylation.
The trRosetta (transform-restrained Rosetta) server is a web-based platform for fast and accurate protein structure prediction, powered by deep learning and Rosetta. With the input of a protein's ...amino acid sequence, a deep neural network is first used to predict the inter-residue geometries, including distance and orientations. The predicted geometries are then transformed as restraints to guide the structure prediction on the basis of direct energy minimization, which is implemented under the framework of Rosetta. The trRosetta server distinguishes itself from other similar structure prediction servers in terms of rapid and accurate de novo structure prediction. As an illustration, trRosetta was applied to two Pfam families with unknown structures, for which the predicted de novo models were estimated to have high accuracy. Nevertheless, to take advantage of homology modeling, homologous templates are used as additional inputs to the network automatically. In general, it takes ~1 h to predict the final structure for a typical protein with ~300 amino acids, using a maximum of 10 CPU cores in parallel in our cluster system. To enable large-scale structure modeling, a downloadable package of trRosetta with open-source codes is available as well. A detailed guidance for using the package is also available in this protocol. The server and the package are available at https://yanglab.nankai.edu.cn/trRosetta/ and https://yanglab.nankai.edu.cn/trRosetta/download/ , respectively.
Uric acid is the end product of purine metabolism in humans, and its excessive accumulation leads to hyperuricemia and urate crystal deposition in tissues including joints and kidneys. Hyperuricemia ...is considered an independent risk factor for cardiovascular and renal diseases. Although the symptoms of hyperuricemia-induced renal injury have long been known, the pathophysiological molecular mechanisms are not completely understood. In this review, we focus on the research advances in the mechanisms of hyperuricemia-caused renal injury, primarily on oxidative stress, endothelial dysfunction, renal fibrosis, and inflammation. Furthermore, we discuss the progress in hyperuricemia management.
In reward-based learning, synaptic modifications depend on a brief stimulus and a temporally delayed reward, which poses the question of how synaptic activity patterns associate with a delayed ...reward. A theoretical solution to this so-called distal reward problem has been the notion of activity-generated “synaptic eligibility traces,” silent and transient synaptic tags that can be converted into long-term changes in synaptic strength by reward-linked neuromodulators. Here we report the first experimental demonstration of eligibility traces in cortical synapses. We demonstrate the Hebbian induction of distinct traces for LTP and LTD and their subsequent timing-dependent transformation into lasting changes by specific monoaminergic receptors anchored to postsynaptic proteins. Notably, the temporal properties of these transient traces allow stable learning in a recurrent neural network that accurately predicts the timing of the reward, further validating the induction and transformation of eligibility traces for LTP and LTD as a plausible synaptic substrate for reward-based learning.
•Hebbian conditioning induces eligibility traces for LTP and LTD in cortical synapses•β2ARs and 5-HT2CRs convert the traces into LTP and LTD, respectively•Anchoring of β2ARs and 5-HT2C is key for trace conversion•Temporal properties of the LTP/D traces allow reward-timing prediction
How is stimulus-evoked activity associated with a time-delayed reward in reinforcement learning? He et al. report on the existence of silent and transient synaptic tags (eligibility traces) that can be converted into long-term changes in synaptic strength by reward-linked neuromodulators.
Among the main bacteria implicated in the pathology of periodontal disease, Aggregatibacter actinomycetemcomitans (Aa) is well known for causing loss of periodontal attachment and systemic disease. ...Recent studies have suggested that secreted extracellular RNAs (exRNAs) from several bacteria may be important in periodontitis, although their role is unclear. Emerging evidence indicates that exRNAs circulate in nanosized bilayered and membranous extracellular vesicles (EVs) known as outer membrane vesicles (OMVs) in gram‐negative bacteria. In this study, we analyzed the small RNA expression profiles in activated human macrophage‐like cells (U937) infected with OMVs from Aa and investigated whether these cells can harbor exRNAs of bacterial origin that have been loaded into the host RNA‐induced silencing complex, thus regulating host target transcripts. Our results provide evidence for the cytoplasmic delivery and activity of microbial EV‐derived small exRNAs in host gene regulation. The production of TNF‐α was promoted by exRNAs via the TLR‐8 and NF‐κB signaling pathways. Numerous studies have linked periodontal disease to neuroinflammatory diseases but without elucidating specific mechanisms for the connection. We show here that intracardiac injection of Aa OMVs in mice showed successful delivery to the brain after crossing the blood‐brain barrier, the exRNA cargos increasing expression of TNF‐α in the mouse brain. The current study indicates that host gene regulation by microRNAs originating from OMVs of the periodontal pathogen Aa is a novel mechanism for host gene regulation and that the transfer of OMV exRNAs to the brain may cause neuroinflammatory diseases like Alzheimer's.—Han, E.‐C., Choi, S.‐Y., Lee, Y., Park, J.‐W., Hong S.‐H., Lee, H.‐J. Extracellular RNAs in periodontopathogenic outer membrane vesicles promote TNF‐α production in human macrophages and cross the blood‐brain barrier in mice. FASEB J. 33, 13412–13422 (2019). www.fasebj.org
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