143 research outputs found
Holographic insulator/superconductor phase transition with Weyl corrections
We analytically investigate the phase transition between the holographic
insulator and superconductor with Weyl corrections by using the variational
method for the Sturm-Liouville eigenvalue problem. We find that similar to the
curvature corrections, in p-wave model, the higher Weyl couplings make the
insulator/superconductor phase transition harder to occur. However, in s-wave
case the Weyl corrections do not influence the critical chemical potential,
which is in contrast to the effect caused by the curvature corrections.
Moreover, we observe that the Weyl corrections will not affect the critical
phenomena and the critical exponent of the system always takes the mean-field
value in both models. Our analytic results are found to be in good agreement
with the numerical findings.Comment: 17 pages, 3 figures and 2 tables. More discussions and references
adde
Investigating enzyme communication during base excision repair in Escherichia coli
Mismatch uracil DNA Glycosylase (MUG) from Escherichia coli is an initiating enzyme in the base excision repair (BER) pathway and is responsible for the removal of 3,N4-ethenocytosine and uracil from DNA during the stationary phase of E.coli cell growth. As with other DNA glycosylases, the abasic product is potentially more harmful than the initial lesion. MUG is widely regarded as a “single turnover” enzyme because it still remains tightly bound to its abasic product after cleavage, thus impeding its catalytic turnover. This may be a general protective mechanism to protect the abasic BER intermediate, whereby coordination of enzyme activity in BER is achieved through displacement of the DNA glycosylase by the downstream apurinic-apyrimidinic (AP) endonuclease. Numerous DNA glycosylases have now been cited as having an enhanced turnover in the presence of an AP endonuclease. The aim of this project is to investigate enzyme coordination between MUG and its both downstream AP endonucleases, Exonuclease III (ExoIII) and Endonuclease IV (EndoIV), in the initial steps of BER. We show here that MUG binds its substrate, abasic DNA and non-specific DNA in the differential modes. A 2:1 cooperative binding stoichiometry with abasic DNA is demonstrated to be of functional significance in both product binding and catalysis via fluorescence anisotropy assays, band shift assays and loss-of-function site-directed mutagenesis methods. The effects of the ExoIII and EndoIV on the MUG turnover kinetics with a U•G containing substrate was investigated. Both ExoIII and EndoIV greatly enhance the turnover of MUG. Furthermore, the analysis of both ExoIII catalytic activity dependent and concentration dependent on MUG turnover demonstrate ExoIII may employ a product scavenging mechanism to enhance MUG turnover. These combined results constitute a new concept that MUG has a pre-catalytic discrimination ability to coordinate its reactivity behavior with the other enzymes.Open Acces
Blockchain technology research and application: a systematic literature review and future trends
Blockchain, as the basis for cryptocurrencies, has received extensive
attentions recently. Blockchain serves as an immutable distributed ledger
technology which allows transactions to be carried out credibly in a
decentralized environment. Blockchain-based applications are springing up,
covering numerous fields including financial services, reputation system and
Internet of Things (IoT), and so on. However, there are still many challenges
of blockchain technology such as scalability, security and other issues waiting
to be overcome. This article provides a comprehensive overview of blockchain
technology and its applications. We begin with a summary of the development of
blockchain, and then give an overview of the blockchain architecture and a
systematic review of the research and application of blockchain technology in
different fields from the perspective of academic research and industry
technology. Furthermore, technical challenges and recent developments are also
briefly listed. We also looked at the possible future trends of blockchain
MURPHY: Relations Matter in Surgical Workflow Analysis
Autonomous robotic surgery has advanced significantly based on analysis of
visual and temporal cues in surgical workflow, but relational cues from domain
knowledge remain under investigation. Complex relations in surgical annotations
can be divided into intra- and inter-relations, both valuable to autonomous
systems to comprehend surgical workflows. Intra- and inter-relations describe
the relevance of various categories within a particular annotation type and the
relevance of different annotation types, respectively. This paper aims to
systematically investigate the importance of relational cues in surgery. First,
we contribute the RLLS12M dataset, a large-scale collection of robotic left
lateral sectionectomy (RLLS), by curating 50 videos of 50 patients operated by
5 surgeons and annotating a hierarchical workflow, which consists of 3 inter-
and 6 intra-relations, 6 steps, 15 tasks, and 38 activities represented as the
triplet of 11 instruments, 8 actions, and 16 objects, totaling 2,113,510 video
frames and 12,681,060 annotation entities. Correspondingly, we propose a
multi-relation purification hybrid network (MURPHY), which aptly incorporates
novel relation modules to augment the feature representation by purifying
relational features using the intra- and inter-relations embodied in
annotations. The intra-relation module leverages a R-GCN to implant visual
features in different graph relations, which are aggregated using a targeted
relation purification with affinity information measuring label consistency and
feature similarity. The inter-relation module is motivated by attention
mechanisms to regularize the influence of relational features based on the
hierarchy of annotation types from the domain knowledge. Extensive experimental
results on the curated RLLS dataset confirm the effectiveness of our approach,
demonstrating that relations matter in surgical workflow analysis
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