Fully Automated Enzymatic Synthesis of Glycans

Oligosaccharides, together with oligonucleotides and oligopeptides, comprise the three major classes of natural biopolymers. Automated systems for oligonucleotide and oligopeptide synthesis have significantly advanced developments in biological science by allowing non-specialists to rapidly and easily access these biopolymers. Researchers have endeavored for decades to develop a comparable general automated system to synthesize oligosaccharides. Such a system would have a revolutionary impact on the understanding of the roles of glycans in biological systems. The main challenge to achieving automated synthesis is the lack of general synthetic methods for routine synthesis of glycans. Currently, the two main methods to access homogeneous glycans and glycoconjugates are chemical synthesis and enzymatic synthesis. Enzymatic glycosylation can proceed stereo- and regiospecifically without protecting group manipulations. Moreover, the reaction conditions of enzyme-catalyzed glycosylations are extremely mild when compared to chemical glycosylations. Over the past few years, methodology towards the automated chemical synthesis of oligosaccharides has been developed. Conversely, while automated enzymatic synthesis is conceptually possible, it is not as well developed. Inspired by the success of automated oligosaccharide synthesis through chemical glycosylation, a fully machine-driven automated system is built up here for oligosaccharides synthesis through enzymatic glycosylation in aqueous solution. The designed automation system is based on the use of a thermosensitive polymer and a commercially available peptide synthesizer to fully achieve automation process. An automated platform for chemo-enzymatic glycopeptide synthesis is built up which easily assembles glycopeptides in an organic phase solvent system before extending oligosaccharide residues by enzymatic glycosylation. Our system is based on the use of an amine-functionalized silica resin to facilitate the linkage of the primers needed to begin the chemical or enzymatic synthesis of the target compounds to a solid support. Using our platform, a peptide from mucin 1 with different important glycan epitopes was successfully prepared with a resin transfer step by hand

End-to-End Quantum-like Language Models with Application to Question Answering

Language Modeling (LM) is a fundamental research topic ina range of areas. Recently, inspired by quantum theory, a novel Quantum Language Model (QLM) has been proposed for Information Retrieval (IR). In this paper, we aim to broaden the theoretical and practical basis of QLM. We develop a Neural Network based Quantum-like Language Model (NNQLM) and apply it to Question Answering. Specifically, based on word embeddings, we design a new density matrix, which represents a sentence (e.g., a question or an answer) and encodes a mixture of semantic subspaces. Such a density matrix, together with a joint representation of the question and the answer, can be integrated into neural network architectures (e.g., 2-dimensional convolutional neural networks). Experiments on the TREC-QA and WIKIQA datasets have verified the effectiveness of our proposed models

Cohomological rank functions and surfaces of general type with pg=q=2p_g=q=2

We classify minimal surfaces $S$ with $p_g=q=2$ and $K_S^2=5$ or $6$

Classification of Interacting Dirac Semimetals

Topological band theory predicts a $\mathbb{Z}$ classification of three-dimensional (3D) Dirac semimetals (DSMs) at the single-particle level. Namely, an arbitrary number of identical bulk Dirac nodes will always remain locally stable and gapless in the single-particle band spectrum, as long as the protecting symmetry is preserved. In this work, we find that this single-particle classification for $C_n$-symmetric DSMs will break down to $\mathbb{Z}_{n/\text{gcd}(2,n)}$ in the presence of symmetry-preserving electron interactions. Our theory is based on a dimensional reduction strategy which reduces a 3D Dirac fermions to 1D building blocks, i.e., vortex-line modes, while respecting all the key symmetries. Using bosonization technique, we find that there exists a minimal number $N=n/\text{gcd}(2,n)$ such that the collection of vortex-line modes in $N$ copies of DSMs can be symmetrically eliminated via four-fermion interactions. While this gapping mechanism does not have any free-fermion counterpart, it yields an intuitive ``electron-trion coupling" picture. By developing a topological field theory for DSMs and further checking the anomaly-free condition, we independently arrive at the same classification results. Our theory paves the way for understanding topological crystalline semimetallic phases in the strongly correlated regime.Comment: 5+7 pages, 1 table, 1 figur

Dynamical Symmetry Indicators for Floquet Crystals

Various exotic topological phases of Floquet systems have been shown to arise from crystalline symmetries. Yet, a general theory for Floquet topology that is applicable to all crystalline symmetry groups is still in need. In this work, we propose such a theory for (effectively) non-interacting Floquet crystals. We first introduce quotient winding data to classify the dynamics of the Floquet crystals with equivalent symmetry data, and then construct dynamical symmetry indicators (DSIs) to sufficiently indicate the "inherently dynamical" Floquet crystals. The DSI and quotient winding data, as well as the symmetry data, are all computationally efficient since they only involve a small number of Bloch momenta. We demonstrate the high efficiency by computing all elementary DSI sets for all spinless and spinful plane groups using the mathematical theory of monoid, and find a large number of different nontrivial classifications, which contain both first-order and higher-order 2+1D anomalous Floquet topological phases. Using the framework, we further find a new 3+1D anomalous Floquet second-order topological insulator (AFSOTI) phase with anomalous chiral hinge modes.Comment: Close to the published versio

Study on coal mine macro, meso and micro safety management system

SummaryIn recent years, the coal mine safety production situation in our country improved year by year, but severe accidents still occurred; the accidents caused great economic loss to the national economy. According to statistical analysis, almost all of the coal mine accidents will expose the hidden danger in before, most of the accidents caused due to safety management not reaching the designated position and the hidden danger management does not take any decision in time. Based on the coal mine safety management holes in our country, the coal mine macro, meso and micro safety management system was established in this paper, which includes meaning and conception of the theories of the macro, meso and micro safety management, and also includes the matching hardware equipment, in order to achieve the hidden danger's closed-loop control and dynamic early warning in the process of coal mine production