Abstract The main purpose of this article is to investigate the qualitative behavior and traveling wave solutions of the fractional stochastic Kraenkel–Manna–Merle equations, which is commonly used ...to simulate the zero conductivity nonlinear propagation behavior of short waves in saturated ferromagnetic materials. Firstly, fractional stochastic Kraenkel–Manna–Merle equations are transformed into ordinary differential equations by using the traveling wave transformation. Secondly, the phase portraits, sensitivity analysis, and Poincaré sections of the two-dimensional dynamic system and its perturbation system of ordinary differential equations are drawn. Finally, the traveling wave solutions of fractional stochastic Kraenkel–Manna–Merle equations are obtained based on the analysis theory of planar dynamical system. Moreover, the obtained three-dimensional graphs of random solutions, two-dimensional graphs of random solutions, and three-dimensional graphs of deterministic solutions are drawn.
Graphene and graphene oxide have attracted tremendous interest over the past decade due to their unique and excellent electronic, optical, mechanical, and chemical properties. This review focuses on ...the functional modification of graphene and graphene oxide. First, the basic structure, preparation methods and properties of graphene and graphene oxide are briefly described. Subsequently, the methods for the reduction of graphene oxide are introduced. Next, the functionalization of graphene and graphene oxide is mainly divided into covalent binding modification, non-covalent binding modification and elemental doping. Then, the properties and application prospects of the modified products are summarized. Finally, the current challenges and future research directions are presented in terms of surface functional modification for graphene and graphene oxide.
Graphene and graphene oxide have attracted tremendous interest over the past decade due to their unique and excellent electronic, optical, mechanical, and chemical properties.
Summary
Plants have served as sources providing humans with metabolites for food and nutrition, biomaterials for living, and treatment for pain and disease. Plants produce a huge array of ...metabolites, with an immense diversity at both the population and individual levels. Dissection of the genetic bases for metabolic diversity has attracted increasing research attention. The concept of genome‐wide association study (GWAS) was extended to studies on the diversity of plant metabolome that benefitted from the development of mass‐spectrometry‐based analytical systems and genome sequencing technologies. Metabolic genome‐wide association study (mGWAS) is one of the most powerful tools for global identification of genetic determinants for diversity of plant metabolism. Recently, mGWAS has been performed for various species with continuous improvements, providing deeper insights into the genetic bases of metabolic diversity. In this review, we discuss fully the achievements to date and remaining challenges that are associated with both mGWAS and mGWAS‐based multi‐dimensional analysis. We begin with a summary of GWAS and its development based on statistical methods and populations. As variation in targeted traits is essential for GWAS, we review metabolic diversity and its rise at both the population and individual levels. Subsequently, the application of mGWAS for plants and its corresponding achievements are fully discussed. We address the current knowledge on mGWAS‐based multi‐dimensional analysis and emerging insights into the diversity of metabolism.
Significance Statement
In this review, we highlight some recent progress in the dissection of metabolic diversity, with an emphasis on metabolic genome‐wide association study (mGWAS) and mGWAS‐based multi‐dimensional analysis.
Cholesterol homeostasis is vital for proper cellular and systemic functions. Disturbed cholesterol balance underlies not only cardiovascular disease but also an increasing number of other diseases ...such as neurodegenerative diseases and cancers. The cellular cholesterol level reflects the dynamic balance between biosynthesis, uptake, export and esterification - a process in which cholesterol is converted to neutral cholesteryl esters either for storage in lipid droplets or for secretion as constituents of lipoproteins. In this Review, we discuss the latest advances regarding how each of the four parts of cholesterol metabolism is executed and regulated. The key factors governing these pathways and the major mechanisms by which they respond to varying sterol levels are described. Finally, we discuss how these pathways function in a concerted manner to maintain cholesterol homeostasis.
This article investigates the dynamical behavior analysis and soliton solutions of the generalized Whitham–Broer–Kaup–Boussineq–Kupershmidt equations in fluid flow dynamics and plasma waves. Firstly, ...the generalized Whitham–Broer–Kaup–Boussineq–Kupershmidt equations are simplified into the ordinary differential equations. Secondly, two-dimensional planar dynamical system and its phase portraits are given by utilizing the theory of planar dynamical system analysis. Finally, the soliton solutions of the generalized Whitham–Broer–Kaup–Boussineq–Kupershmidt equations are presented by using the fourth-order complete discriminant system. In order to better reveal the soliton propagation phenomenon of the generalized Whitham–Broer–Kaup–Boussineq–Kupershmidt equations, some three-dimensional, two-dimensional, and contour graphs of the solutions were drawn.
•The main purpose of this paper is to study dynamical behavior analysis and soliton solutions of the generalized Whitham–Broer–Kaup–Boussineq–Kupershmidt equations.•Some specific parameters are given to draw the plane phase portrait of the dynamic system.•The soliton solutions of the generalized Whitham–Broer–Kaup–Boussineq–Kupershmidt equation are constructed.
As a 100% atom-economy process, direct oxidation of methane into methanol remains as a grand challenge due to the dilemma between activation of methane and over-oxidation of methanol. Here, we report ...that water enabled mild oxidation of methane into methanol with >99% selectivity over Au single atoms on black phosphorus (Au
/BP) nanosheets under light irradiation. The mass activity of Au
/BP nanosheets reached 113.5 μmol g
in water pressured with 33 bar of mixed gas (CH
:O
= 10:1) at 90 °C under light irradiation (1.2 W), while the activation energy was 43.4 kJ mol
. Mechanistic studies revealed that water assisted the activation of O
to generate reactive hydroxyl groups and •OH radicals under light irradiation. Hydroxyl groups reacted with methane at Au single atoms to form water and CH
* species, followed by oxidation of CH
* via •OH radicals into methanol. Considering the recycling of water during the whole process, we can also regard water as a catalyst.
Exploring the Diversity of Plant Metabolism Fang, Chuanying; Fernie, Alisdair R.; Luo, Jie
Trends in plant science,
January 2019, 2019-01-00, 20190101, Letnik:
24, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Plants produce a huge array of metabolites, far more than those produced by most other organisms. Unraveling this diversity and its underlying genetic variation has attracted increasing research ...attention. Post-genomic profiling platforms have enabled the marriage and mining of the enormous amount of phenotypic and genetic diversity. We review here achievements to date and challenges remaining that are associated with plant metabolic research using multi-omic strategies. We focus mainly on strategies adopted in investigating the diversity of plant metabolism and its underlying features. Recent advances in linking metabotypes with phenotypic and genotypic traits are also discussed. Taken together, we conclude that exploring the diversity of metabolism could provide new insights into plant evolution and domestication.
Plants produce a huge array of metabolites in spatiotemporal- and/or environment-dependent manner, which not only make it a challenge to understand plant metabolic diversity but also render plants ideal models for identifying metabolites and dissecting metabolic pathways.
In addition to reverse genetic approaches, forward genetic-based approaches combining genome sequences with population genetics provide clues for understanding biological mechanisms.
Genomic evolution provides the genetic basis for metabolic diversity, including gene duplication, gene loss, transposon insertion, and the evolution of substrate preference. Selective events during crop domestication and improvement have also played a vital role in the evolution of metabolism.
Analysis of the metabolome in genetically diverse populations can also facilitate the dissection of phenotypic traits, and will eventually lead to metabolite-assisted breeding of crops.
Trifluoromethylthiolated molecules are an important class of biologically active compounds and potential drug candidates. Because of the lack of efficient synthetic methods, catalytic ...enantioselective construction of these molecules is rare and remains a challenge. To expand this field, we herein disclose a bifunctional selenide-catalyzed approach for the synthesis of various chiral trifluoromethylthiolated tetrahydronaphthalenes bearing an all-carbon quaternary stereocenter with gem-diaryl-tethered alkenes and alkynes by merging desymmetrization and trifluoromethylthiolation strategy. The products are obtained in high yields with excellent enantio- and diastereo-selectivities. This method can be applied to the desymmetrization and sulfenylation of diols as well. Computational studies reveal that selenide can activate the electrophilic reagent better than sulfide, confirming the higher efficiency of selenide catalysis in these reactions. On the basis of the theoretical calculations, an acid-derived anion-binding interaction is suggested to exist in the whole pathway and accounts for the observed high selectivities.
Actinomycetes are outstanding and fascinating sources of potent bioactive compounds, particularly antibiotics. In recent years, rare actinomycetes have had an increasingly important position in the ...discovery of antibacterial compounds, especially
Micromonospora
,
Actinomadura
and
Amycolatopsis
. Focusing on the period from 2008 to 2018, we herein summarize the structures and bioactivities of secondary metabolites from rare actinomycetes, involving 21 genera.
A detailed introduction to the structures and bioactivities of secondary metabolites from rare actinomycetes is made.
This paper presents generalized channel coding theorems for a time-slotted distributed communication system where a transmitter-receiver pair is communicating in parallel with other transmitters. ...Assume that the channel code of each transmitter is chosen arbitrarily in each time slot. The coding choice of a transmitter is denoted by a code index parameter, which is known neither to other transmitters nor to the receiver. Fundamental performance limitation of the system is characterized using an achievable region defined in the space of the code index vectors. As the codeword length is taken to infinity, for all code index vectors inside the region, the receiver will decode the message reliably, while for all code index vectors outside the region, the receiver will report a collision reliably. A generalized system error performance measure is defined as the weighted sum of probabilities of different types of communication error events. Assume that the receiver chooses an "operation region" and intends to decode the message if the code index vector is inside the operation region. Achievable bounds on the tradeoff between the operation region and the generalized error performance measure are obtained under the assumption of a finite codeword length.
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