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"Xiao, Wen"
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خواطر نثرية للأديب الصيني ما يوي تشن، يسرد فيها مجموعة من المقتطفات النثرية التي تعكس تكوينه الذاتي ومشاعره تجاه قوميته، يتحدث فيها عن مشاهداته وانطباعاته ويومياته في نثر أدبي شديد العذوبة. ومنها أن تكون وحيدا، عين الروح، الطفو على سطح البحر، نهر الأمس، الانسياب مع أحداث الماضي، الأمور الحياتية كالدخان ... وموضوعات أخرى.
Book
Choreographed entanglement dances
The discovery of topological phases of matter forced condensed matter physicists to question and reexamine some of the basic notions of their discipline. Wen reviews the progress of the field that took a sharp turn from Landau's broken symmetry paradigm to arrive at the modern notions of topological order and quantum entanglement in many-body systems. This development was made possible by using increasingly sophisticated mathematical formalisms. Science , this issue p. eaal3099 It has long been thought that all different phases of matter arise from symmetry breaking. Without symmetry breaking, there would be no pattern, and matter would be featureless. However, it is now clear that for quantum matter at zero temperature, even symmetric disordered liquids can have features, giving rise to topological phases of quantum matter. Some of the topological phases are highly entangled (that is, have topological order), whereas others are weakly entangled (that is, have symmetry-protected trivial order). This Review provides a brief summary of these zero-temperature states of matter and their emergent properties, as well as their importance in unifying some of the most basic concepts in nature.
Journal Article
Mammalian WTAP is a regulatory subunit of the RNA N6-methyladenosine methyltransferase
The methyltransferase like 3 （METTL3）-containing methyltransferase complex catalyzes the N6-methyladenosine （m6A） formation, a novel epitranscriptomic marker; however, the nature of this complex remains largely unknown. Here we report two new components of the human m6A methyltransferase complex, Wilms＇ tumor 1-associating protein （WTAP） and methyltransferase like 14 （METTL14）. WTAP interacts with METTL3 and METTL14, and is required for their localization into nuclear speckles enriched with pre-mRNA processing factors and for catalytic ac- tivity of the m6A methyltransferase in vivo. The majority of RNAs bound by WTAP and METTL3 in vivo represent mRNAs containing the consensus m6A motif. In the absence of WTAP, the RNA-binding capability of METTL3 is strongly reduced, suggesting that WTAP may function to regulate recruitment of the m6A methyltransferase complex to mRNA targets. Furthermore, transcriptomic analyses in combination with photoactivatable-ribonucleoside-en- hanced crosslinking and immunoprecipitation （PAR-CLIP） illustrate that WTAP and METTL3 regulate expression and alternative splicing of genes involved in transcription and RNA processing. Morpholino-mediated knockdown targeting WTAP and/or METTL3 in zebrafish embryos caused tissue differentiation defects and increased apoptosis. These findings provide strong evidence that WTAP may function as a regulatory subunit in the m6A methyltransferase complex and play a critical role in epitranscriptomic regulation of RNA metabolism.
Journal Article
21st century Maritime Silk Road : a peaceful way forward
\"This book focuses on understanding the characteristics of the marine environment; overall characteristic of the marine resources (especially the marine new energy) and their current utilization; important routes, channels, and ports; and the Maritime Silk Road from the perspective of international law. It also discusses the significance and opportunities of the Maritime Silk Road initiative, analyzes the challenges involved in the construction of the Maritime Silk Road and provides corresponding countermeasures. Based on the above research, this book also proposes to construct a comprehensive application platform for the Maritime Silk Road that will be a practical tool for decision-making. This book is one of the series publications on the 21st century Maritime Silk Road (shortened as \"Maritime Silk Road\"). This series publications cover the characteristics of the marine environment and marine new energy, remote islands and reefs construction, climate change, early warning of wave disasters, legal escort, marine environment and energy big data construction, etc. contributing to the safe and efficient construction of the Maritime Silk Road. It aims to improve our knowledge of the ocean, thus to improve the capacity for marine construction, enhance the viability of remote islands and reefs, ease the energy crisis and protect the ecological environment, improve the quality of life of residents along the Maritime Silk Road, and protect the rights, interests of the countries and regions participating in the construction of the Maritime Silk Road. It will be a valuable reference for decision-makers, researchers, and marine engineers working in the related fields.\"-- Provided by publisher.
Book
Symmetric Gapped Interfaces of SPT and SET States: Systematic Constructions
Symmetry-protected topological (SPT) states have boundary ’t Hooft anomalies that obstruct the effective boundary theory realized in its own dimension with UV completion and with an on-siteG-symmetry. In this work, yet we show that a certain anomalous non-on-siteG-symmetry along the boundary becomes on-site when viewed as an extendedH-symmetry, via a suitable group extension1→K→H→G→1. Namely, a nonperturbative global (gauge or gravitational) anomaly inGbecomes anomaly free inH. This guides us to construct an exactly soluble lattice path integral and Hamiltonian of symmetric gapped boundaries applicable to any SPT state of any finite symmetry group, including on-site unitary and antiunitary time-reversal symmetries. The resulting symmetric gapped boundary can be described either by anH-symmetry extended boundary in any spacetime dimension or, more naturally, by a topological emergentK-gauge theory with a global symmetryGon a3+1Dbulk or above. The excitations on such a symmetric topologically ordered boundary can carry fractional quantum numbers of the symmetryG, described by representations ofH. (Applying our approach to a1+1Dboundary of2+1Dbulk, we find that a deconfined gauge boundary indeed has spontaneous symmetry breaking with long-range order. The deconfined symmetry-breaking phase crosses over smoothly to a confined phase without a phase transition.) In contrast to known gapped boundaries or interfaces obtained via symmetry breaking (either global symmetry breaking or the Anderson-Higgs mechanism for gauge theory), our approach is based on symmetry extension. More generally, applying our approach to SPT states, topologically ordered gauge theories, and symmetry enriched topologically ordered (SET) states leads to generic boundaries or interfaces constructed with a mixture of symmetry breaking, symmetry extension, and dynamical gauging.
Journal Article
Asymmetric three-component olefin dicarbofunctionalization enabled by photoredox and copper dual catalysis
The intermolecular three-component alkene vicinal dicarbofunctionalization (DCF) reaction allows installation of two different carbon fragments. Despite extensive investigation into its ionic chemistry, the enantioseletive radical-mediated versions of DCF reactions remain largely unexplored. Herein, we report an intermolecular, enantioselective three-component radical vicinal dicarbofunctionalization reaction of olefins enabled by merger of radical addition and cross-coupling using photoredox and copper dual catalysis. Key to the success of this protocol relies on chemoselective addition of acyl and cyanoalkyl radicals, generated in situ from the redox-active oxime esters by a photocatalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto the alkenes to form new carbon radicals. Single electron metalation of such newly formed carbon radicals to TMSCN-derived
L1
Cu(II)(CN)
2
complex leads to asymmetric cross-coupling. This three-component process proceeds under mild conditions, and tolerates a diverse range of functionalities and synthetic handles, leading to valuable optically active
β
–cyano ketones and alkyldinitriles, respectively, in a highly enantioselective manner (>60 examples, up to 97% ee).
Vicinal dicarbofunctionalization (DCF) reactions of alkenes have been extensively explored in ionic chemistry but the enantioselective radical mediated version of DCF remains largely unexplored. Here, the authors demonstrate a radical vicinal DCF reaction of olefins by merging of radical addition and cross-coupling using photoredox and copper dual catalysis.
Journal Article
Classification of ( 3 + 1 ) D Bosonic Topological Orders: The Case When Pointlike Excitations Are All Bosons
Topological orders are new phases of matter beyond Landau symmetry breaking. They correspond to patterns of long-range entanglement. In recent years, it was shown that in1+1Dbosonic systems, there is no nontrivial topological order, while in2+1Dbosonic systems, the topological orders are classified by the following pair: a modular tensor category and a chiral central charge. In this paper, following a new line of thinking, we find that in3+1Dthe classification is much simpler than it was thought to be; we propose a partial classification of topological orders for3+1Dbosonic systems: If all the pointlike excitations are bosons, then such topological orders are classified by a simpler pair(G,ω4): a finite groupGand its group 4-cocycleω4∈H4[G;U(1)](up to group automorphisms). Furthermore, all such3+1Dtopological orders can be realized by Dijkgraaf-Witten gauge theories.
Journal Article