The electroreduction of CO2 to value‐added chemicals such as CO is a promising approach to realize carbon‐neutral energy cycle, but still remains big challenge including low current density. Covalent ...organic frameworks (COFs) with abundant accessible active single‐sites can offer a bridge between homogeneous and heterogeneous electrocatalysis, but the low electrical conductivity limits their application for CO2 electroreduction reaction (CO2RR). Here, a 2D conductive Ni‐phthalocyanine‐based COF, named NiPc‐COF, is synthesized by condensation of 2,3,9,10,16,17,23,24‐octa‐aminophthalocyaninato Ni(II) and tert‐butylpyrene‐tetraone for highly efficient CO2RR. Due to its highly intrinsic conductivity and accessible active sites, the robust conductive 2D NiPc‐COF nanosheets exhibit very high CO selectivity (>93%) in a wide range of the applied potentials of −0.6 to −1.1 V versus the reversible hydrogen electrode (RHE) and large partial current density of 35 mA cm−2 at −1.1 V versus RHE in aqueous solution that surpasses all the conventional COF electrocatalysts. The robust NiPc‐COF that is bridged by covalent pyrazine linkage can maintain its CO2RR activity for 10 h. This work presents the implementation of the conductive COF nanosheets for CO2RR and provides a strategy to enhance energy conversion efficiency in electrocatalysis.
A conductive nickelophthalocyanine‐based 2D covalent organic framework is synthesized and employed as a robust and efficient electrocatalyst for CO2 electroreduction reaction, providing a new route to design highly efficient porous framework materials for the enhanced electrocatalysis via improving electrical conductivity.
Histone post-translational modifications are crucial epigenetic mechanisms regulating a variety of biological events. Besides histone lysine acetylation, a repertoire of acylation types have been ...identified, including formylation, propionylation, butyrylation, crotonylation, 2-hydroxyisobutyrylation, β-hydroxybutyrylation, succinylation, malonylation, glutarylation and benzoylation. From a structural perspective, here we summarize the writers and erasers of histone acylations and explain the molecular basis of these enzymes catalyzing non-acetyl histone acylations with a focus on histone crotonylation and β-hydroxybutyrylation. Histone acylation readout, non-histone acylations and metabolic regulation are also discussed in this review.
A
bstract
Recent perturbative calculation of quasi gluon distribution function at one-loop level shows the existence of extra linear ultraviolet divergences in the cut-off scheme. We employ the ...auxiliary field approach, and study the renormalization of gluon operators. The non-local gluon operator can mix with new operators under renormalization, and the linear divergences in quasi distribution function can be into the newly introduced operators. After including the mixing, we find the improved quasi gluon distribution functions contain only logarithmic divergences, and thus can be used to extract the gluon distribution in large momentum effective theory.
Modulation of chromatin structure and/or modification by Polycomb repressive complexes (PRCs) provides an important means to partition the genome into functionally distinct subdomains and to regulate ...the activity of the underlying genes. Both the enzymatic activity of PRC2 and its chromatin recruitment, spreading, and eviction are exquisitely regulated via interactions with cofactors and DNA elements (such as unmethylated CpG islands), histones, RNA (nascent mRNA and long noncoding RNA), and R-loops. PRC2-catalyzed histone H3 lysine 27 trimethylation (H3K27me3) is recognized by distinct classes of effectors such as canonical PRC1 and BAH module-containing proteins (notably BAHCC1 in human). These effectors mediate gene silencing by different mechanisms including phase separation-related chromatin compaction and histone deacetylation. We discuss recent advances in understanding the structural architecture of PRC2, the regulation of its activity and chromatin recruitment, and the molecular mechanisms underlying Polycomb-mediated gene silencing. Because PRC deregulation is intimately associated with the development of diseases, a better appreciation of Polycomb-based (epi)genomic regulation will have far-reaching implications in biology and medicine.
The catalytic activity of the PRC2 core is delicately regulated by conformational changes (autoinhibition versus allosteric activation), its non-core cofactors, and the chromatin context.A collection of factors, including DNA cis-elements (such as unmethylated CpG islands), RNA, R-loops, and chromatin modifications, are involved in the regulation of PRC2 targeting and spreading in the chromatin, as well as its eviction or functional restriction.A local redeposition model is postulated in which, during DNA replication, local recycling of parental H3K27me3 assists PRC2-mediated propagation of H3K27me3 at newly synthesized histones.Liquid–liquid phase separation establishes protein condensates of the H3K27me3-reading cPRC1 complex, leading to chromatin compaction and Polycomb-mediated gene silencing.Conserved BAH modules emerge as a new class of H3K27me3-specific readers that mediate gene silencing by Polycomb proteins across fungi, plants, and mammals.Key questions remain to be addressed regarding the complex crosstalk between PRC variants, chromatin, transcription (RNA), and H3K27me3 readers in a range of tissues and cell types; nonhistone- or non-PRC-related regulatory activities of Polycomb proteins bring additional layers of complexity.
Gluon quasidistribution function at one loop Wang, Wei; Zhao, Shuai; Zhu, Ruilin
European physical journal. C, Particles and fields,
02/2018, Letnik:
78, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We study the unpolarized gluon quasidistribution function in the nucleon at one loop level in the large momentum effective theory. For the quark quasidistribution, power law ultraviolet divergences ...arise in the cut-off scheme and an important observation is that they all are subjected to Wilson lines. However for the gluon quasidistribution function, we first point out that the linear ultraviolet divergences also exist in the real diagram which is not connected to any Wilson line. We then study the one loop corrections to parton distribution functions in both cut-off scheme and dimensional regularization to deal with the ultraviolet divergences. In addition to the ordinary quark and gluon distributions, we also include the quark to gluon and gluon to quark splitting diagrams. The complete one-loop matching factors between the quasi and light cone parton distribution functions are presented in the cut-off scheme. We derive the
P
z
evolution equation for quasi parton distribution functions, and find that the
P
z
evolution kernels are identical to the DGLAP evolution kernels.
The genetic information of human cells is stored in the context of chromatin, which is subjected to DNA methylation and various histone modifications. Such a 'language' of chromatin modification ...constitutes a fundamental means of gene and (epi)genome regulation, underlying a myriad of cellular and developmental processes. In recent years, mounting evidence has demonstrated that miswriting, misreading or mis-erasing of the modification language embedded in chromatin represents a common, sometimes early and pivotal, event across a wide range of human cancers, contributing to oncogenesis through the induction of epigenetic, transcriptomic and phenotypic alterations. It is increasingly clear that cancer-related metabolic perturbations and oncohistone mutations also directly impact chromatin modification, thereby promoting cancerous transformation. Phase separation-based deregulation of chromatin modulators and chromatin structure is also emerging to be an important underpinning of tumorigenesis. Understanding the various molecular pathways that underscore a misregulated chromatin language in cancer, together with discovery and development of more effective drugs to target these chromatin-related vulnerabilities, will enhance treatment of human malignancies.
A
bstract
We present results for one-loop corrections to the recently introduced “gluon condensate” PDF
F
(
x
). In particular, we give expression for the
gg
-part of its evolution kernel. To enforce ...strict compliance with the gauge invariance requirements, we have used on-shell states for external gluons, and have obtained identical results both in Feynman and light-cone gauges. No “zero mode”
δ
(
x
) terms were found for the twist-4 gluon PDF
F
(
x
). However a
q
2
δ
(
x
) term was found for the
ξ
= 0 GPD
F
(
x, q
2
) at nonzero momentum transfer
q
. Overall, our results do not agree with the original attempt of one-loop calculations of
F
(
x
) for gluon states, which sets alarm warning for calculations that use matrix elements with virtual external gluons and for lattice renormalization procedures based on their results.
Salinization is a worldwide emerging threat to freshwater systems. It can be caused by various salts with different toxicity to freshwater organisms. Populations of freshwater organisms have been ...shown to rapidly evolve adaptations to salinity, yet it remains unclear whether adaptation to one salt increases tolerance or, conversely, susceptibility to other salts. Using an experimental evolution approach, we subjected replicate populations of a planktonic monogonont rotifer species (Brachionus calyciflorus Pallas) to non‐saline and NaCl‐enriched environments. A subsequent multigenerational common garden (CG) transplant experiment demonstrated rapid microevolutionary adaptation to salinity. A second CG experiment provided evidence that adaptation to NaCl increases tolerance mainly to CaCl2 but to a much lesser extent to Na2SO4. Increased tolerance to CaCl2 was associated with increased tolerance to Ca2+ ion toxicity. In contrast, acquired tolerance to Na2SO4 could not be shown to involve an improved ability to cope with SO42− ion toxicity. Our results highlight that the evolution of cross‐tolerance may expand the temporal and spatial dimensions under which the ecological consequences of salt adaptation apply.
The Internet of Things (IoT) infrastructure with numerous diverse physical devices are growing up rapidly, which need a dynamic services coordination approach that can integrate those heterogeneous ...physical devices into the context-aware IoT infrastructure. This paper proposes a situation-aware dynamic IoT services coordination approach. First, focusing on the definition of formal situation event pattern with event selection and consumption strategy, an automaton-based situational event detection algorithm is proposed. Second, the enhanced event-condition-action is used to coordinate the IoT services effectively, and also the collaboration process decomposing algorithm and the rule mismatch detection algorithms are proposed. Third, the typical scenarios of IoT services coordination for smart surgery process are also illustrated and the measurement and analysis of the platform's performance are reported. Finally, the conclusions and future works are given.
A
bstract
We present results for the
gg
-part of the one-loop corrections to the recently introduced “topological charge” GPD
F
~
(
x, q
2
). In particular, we give expression for its evolution ...kernel. To enforce strict compliance with the gauge invariance requirements, we have used on-shell states for external gluons, and have obtained identical results both in Feynman and light-cone gauges. No “zero mode”
δ
(
x
) terms were found for the twist-4 gluon GPD
F
~
(
x, q
2
).