Character Of Structure Research Articles

Lewis-Acid Mediated Reactivity in Single-Molecule Junctions.

While chemical reactions at a gold electrode can be monitored using molecular conductance and driven by extrinsic stimuli, the intrinsic properties of the nanostructured interface may perform important additional functions that are not yet well understood. Here we evaluate these properties in studies of single-molecule junctions formed from components comprising 4,4'-biphenyl backbones functionalized with 12 different sulfur-based linker groups. With some linkers, we find evidence for in situ S-C(sp3) bond breaking, and C(sp2)-C(sp3) bond forming, reactions consistent with the ex situ transformations expected for those groups in the presence of a Lewis acid. Notably, we also approach the limits of substituent influence on the conductance of physisorbed sulfur-linked junctions. As an illustrative example, we show that a tert-butylthio-functionalized precursor can form both chemisorbed (Au-S) junctions, consistent with heterolytic S-C(sp3) bond cleavage and generation of a stable tert-butyl carbocation, as well as physisorbed junctions that are >1 order of magnitude lower conductance than analogous junctions comprising cyclic "locked" thioether contacts. These findings are supported by a systematic analysis of model thioether components comprising different simple hydrocarbon substituents of intermediate size, which do not form chemisorbed contacts and further clarify the inverse relationship between conductance and substituent steric bulk. First-principles calculations confirm that bulky sulfur-substituents increase the probability of forming junction geometries with reduced electronic coupling between the electrode and π-conjugated molecular backbone. Together, this work helps to rationalize the dual roles that linker chemical structure and metal electrode Lewis character can play in mediating interfacial reactions in break-junction experiments.

Unraveling the Band Structure and Orbital Character of a π-Conjugated 2D Graphdiyne-Based Organometallic Network.

Graphdiyne-based carbon systems generate intriguing layered sp-sp2 organometallic lattices, characterized by flexible acetylenic groups connecting planar carbon units through metal centers. At their thinnest limit, they can result in 2D organometallic networks exhibiting unique quantum properties and even confining the surface states of the substrate, which is of great importance for fundamental studies. In this work, the on-surface synthesis of a highly crystalline 2D organometallic network grown on Ag(111) is presented. The electronic structure of this mixed honeycomb-kagome arrangement - investigated by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy - reveals a strong electronic conjugation within the network, leading to the formation of two intense electronic band-manifolds. In comparison to theoretical density functional theory calculations, it is observed that these bands exhibit a well-defined orbital character that can be associated with distinct regions of the sp-sp2 monomers. Moreover, it is found that the halogen by-products resulting from the network formation locally affect the pore-confined states, causing a significant energy shift. This work contributes to the understanding of the growth and electronic structure of graphdiyne-like 2D networks, providing insights into the development of novel carbon materials beyond graphene with tailoredproperties.

Unsteady Secondary Flow Structure at a Large River Confluence

AbstractRiver confluences, which are characterized by complex hydrodynamics, are key nodes for flood control and environmental protection. Two field surveys were carried out at the confluence of the Yangtze River and Poyang Lake to investigate the transient character of flow structures, which are often assumed steady. Repeat‐transect acoustic Doppler current profile measurements were processed and analyzed, adopting a new method to separate mean flow from turbulence and measurement error based on physics‐informed generalized Tikhonov regularization. The two field surveys were characterized by two distinct mixing interface modes: A so‐called Kelvin–Helmholtz (KH) mode, and a wake mode. In KH mode, large‐scale flow fluctuations were observed. These flow fluctuations exert a substantial influence on the alternation of secondary flows by changing the water surface pressure gradient, affecting the intensity of secondary flows rather than their spatial structure. We infer that temperature‐induced stratification is the main cause of this. In the wake mode, multiple vortices in the wake region at the confluence apex also produced flow fluctuations, directly related to the primary velocity gradient. We argue that even for constant incoming flows, secondary flow at river confluences can exhibit channel‐scale unsteadiness related to migration of the turbulent mixing interface. Our findings highlight the crucial role of density effects in regulating secondary flow unsteadiness, which is essential for understanding contaminant and sediment dispersal in river systems.

Words, Characters and Messages in the Queer Romance of Generation Z

Abstract: This article presents an attempt to analyze the structural elements and characters that make Casey McQuiston's debut novel Red, White & Royal Blue so popular with readers, as well as the challenges posed to viewers by director Matthew Lopez and the creative team of the eponymous film, which immediately became a cultural phenomenon with many fans among viewers. The novel and its film adaptation follow the relationship between two young men from prominent families against the constraints of a heteronormative society. The article investigates a pertinent and contemporary issue from a social and intercultural perspective. The primary objective is to identify and examine linguistic and communicative characteristics, including the contextual use of words and expressions, within a specific socio-cultural framework as depicted in two distinct art forms: literature and cinema. The analysis incorporates comparative elements by referencing well-known works that address similar themes related to cultural differences, behavioral patterns, stereotypes, prejudices concerning LGBTQ+, queer, cultural dynamics of Generation Z, and the influence of heteronormative societal structures. This text seeks to delineate the boundaries of a new interdisciplinary research field focused on the concept of difference. It aims to propose potential research methodologies that contribute to the development of a comprehensive methodological framework, free from bias. In accordance with the principles of academic correctness, the novel and the film Red, White & Royal Blue are analyzed. Keywords: Red, White & Royal Blue, RW&RB, new adult fiction, Casey McQuiston, Matthew López, Generation Z, rom-com, LGBTQ+, queer.

The impacts of COVID-19 on youth activisms in Spain (2020–2022)

ABSTRACT The COVID-19 pandemic can be considered a ‘period of emergency critical juncture’ that affected social movements and collective action. Based on this premise, this article analyses its impact on youth activisms in Spain, investigating its structural or circumstantial nature. The research used in-depth interviews and focused on three types of youth activisms - feminisms, environmentalisms, and socio-community - chosen for either their mobilising force prior to the pandemic or their relevance during it. In order to assess the temporary or permanent effects of the pandemic on these activisms, three dimensions were studied: organisational forms, mobilisation issues and repertoires of action. The results allow us to identify short-term impacts, such as the interruption of the rhythm of activism, the prominence of the virtual world, and the creation of pragmatic alliances of local collective action, while at the same time allowing us to glimpse those that may have a more structural character such as the inclusion of mental health as an issue and the normalisation of repression and criminalisation of activism in securitarian contexts.

A new species of the genus Scolopostethus (Heteroptera: Rhyparochromidae) from Middle Asia

A new species, Scolopostethus gissarensis sp. nov. (Heteroptera: Rhyparochromidae: Rhyparochrominae: Drymini), is described from Middle Asia (Kazakhstan, Uzbekistan, Tajikistan, and Kyrgyzstan). The new species is placed in the genus Scolopostethus Fieber, 1860, based on a combination of morphological characters. The structural characters of the foreleg and the paramere distinctly differentiate it from other Palaearctic species within this genus. Scolopostethus gissarensis sp. nov. is primarily compared to S. decoratus (Hahn, 1833). Colour photographs depicting the habitus and structural details of the body are provided for both S. gissarensis sp. nov. and S. decoratus (Hahn, 1833).

Broadened and enhanced MIR emission in Yb3+/Er3+/Dy3+ triply-doped CaYAlO4 crystal

Yb3+/Er3+/Dy3+ triply-doped CaYAlO4 single crystal was successfully grown to obtain the broadened and enhanced 3 μm MIR emission. The structure characters were studied by XRD measurement. The optical properties and energy transfer mechanism between Yb3+, Er3+, and Dy3+ were investigated according to the measured absorption spectra, emission spectra, and fluorescence decay curves. The absorption spectra show that the triply-doped crystal could be effective pumped by 980 nm due to the introduced of Yb3+ and Er3+. In comparison with Dy3+ singly-doped CaYAlO4 crystal, a broadened and enhanced ∼3 μm MIR emission with a full width at half maximum (FWHM) of 286 nm was obtained due to the fact that there exists effective energy transfer process from Yb3+ and Er3+ to Dy3+. For Yb3+, it serves as an effective sensitized ion. For Er3+, it could be not only used as an effective sensitized ion, but also as a 2.7 μm MIR emission center. For Dy3+, it serves as a deactivating ion to solve the self-termination “bottleneck” effect of Er3+, and more importantly, as an emission center to achieve 3 μm emission. The comprehensive effect is to obtain enhanced and broadened MIR emission in the triply-doped crystal. In addition, the corresponding energy transfer efficiency from Yb3+: 2F5/2 to Dy3+: 6H5/2 is as high as 90 %. Hence, the Yb3+/Er3+/Dy3+: CaYAlO4 crystal could be used as promising medium for MIR broadband tunable laser applications.

Direct Observations of Spontaneous In-Plane Electronic Polarization in 2D Te Films.

Single-element polarization in low dimensions is fascinating for constructing next-generation nanoelectronics with multiple functionalities, yet remains difficult to access with satisfactory performance. Here, spectroscopic evidences are presented for the spontaneous electronic polarization in tellurium (Te) films thinned down to bilayer, characterized by low-temperature scanning tunneling microscopy/spectroscopy. The unique chiral structure and centrosymmetry-breaking character in 2DTe gives rise to sizable in-plane polarization with accumulated charges, which is demonstrated by the reversed band-bending trends at opposite polarization edges in spatially resolved spectra and conductance mappings. The polarity of charges exhibits intriguing influence on imaging the moiré superlattice at the Te-graphene interface. Moreover, the plain spontaneous polarization robustly exists for various film thicknesses, and can universally preserve against different epitaxial substrates. The experimental validations of considerable electronic polarization in Te multilayers thus provide a realistic platform for promisingly facilitating reliable applications in microelectronic devices.

On Seedling Morphoanatomy of Asteraceae Campestral Species: Some Adaptative and Taxonomic Considerations

Theoretical Framework: The vegetation of Parana State fields is composed mainly of woody grassy savanna, and one of the largest families in specific richness is Asteraceae. The campestral Asteraceae occurs in three microhabitats as dry fields (steppes “stricto sensu”), rocky outcrops (rupestrian vegetation refuges) and humid fields (higrophyllous steppes). Morphology and structure of Asteraceae seedlings can be useful for species recognition in the field at the juvenile stage, and to understand how seedlings establish themselves in different microhabitats. Objective: The aim of this paper was to analyze the seedling structure of 17 Asteraceae species, and to summarize some considerations on anatomical characters of the seedlings, which may be variations environmentally induced and they have some taxonomic or evolutionary value. Method: Cipselae of 17 species of Asteraceae were collected in the state parks of Paraná, Brazil, and placed to germinate in Petri plates. The seedling development occurred in greenhouse. Root, hypocotyl, cotyledons, epicotyl and eophylls were sectioned in rotation microtome, and analyzed in light microscope. Cotyledons and eophylls were investigated in a scanning electronic microscope. Results: Roots are diarch or tetrarch. Hypocotyl may have the root structure and partially or wholly as transition root-stem structure. Epicotyl shows the stem structure. Cotyledons and eophylls are dorsiventral. Trichome density and amphistomaty are xeromorphic characters that occur in the cotyledons and eophylls of the species. Conclusion: Some structural characters have diagnostic value for separation of investigated species, such as hypocotyl structure, root/stem transition type, epidermis, mesophyll tissues and midrib saliency of the cotyledons and eophylls, and presence of secretory ducts.

Mechanical behaviour and instability mechanism of sandstones with impact tendency under different loading paths

ABSTRACT To reveal the instability and failure mechanism of pillars with impact tendency, the Brazilian test, uniaxial compressive test, cyclic loading and unloading (CLU) tests were performed on sandstones which had impact tendency. The stress drop phenomenon was obvious in the fracture stage during the Brazilian test. The main tensile crack with penetration type appeared. Under the CLU condition, the CLU had a significant effect in enhancing the mechanical character of rocks. Under the combined loading, the character stress of rocks tested with the CLU was greater than the uniaxial loading. Moreover, the greater the first cyclic threshold, the greater the character stress of rocks. Under the uniaxial loading, the failed samples showed tensile fractures. The damage location of the samples was closely related to the Poisson effect and the ending face effect. With the electron microscope which had the same magnification, the crack deterioration degree of samples under the uniaxial loading was greater than the CLU condition. Moreover, with the first cycle threshold increasing, the surface roughness of rocks gradually decreased. The quantity of secondary micro cracks gradually decreased. The propagation and penetration phenomenon gradually disappeared. The micro structure and loading properties of rocks were affected by the bonding force and structural characters between the internal structure and matrix. Based on the micro-seismic signal of the damaging threshold, the seismic source damage location can be located. Moreover, the pillar-typed burst area can be forewarned. This research benefits predicting the pillar-typed burst disaster.

Analysis of the structural integrity of wooden structures in service: case study with diagnostic methodologies and rehabilitation strategies

The rehabilitation, restoration, or reinforcement of wooden structures requires a thorough assessment of their "health" status. This evaluation is akin to Structural Integrity Assessment (SIA), which employs multidisciplinary techniques to determine the state of accumulated damage and its growth rate, enabling the prediction of the remaining service life of the structure and the scheduling of corrective actions. This case study aims to investigate the structural health of a wooden pergola in Belo Horizonte, MG, Brazil, applying SIA based on methods of propedeutics, diagnosis, and therapy. Non-destructive tests such as acoustic tomography, controlled penetration test (Resistograph), and impact test (Pilodyn) were conducted for propedeutics and diagnosis. Macroscopic visual assessment identified the wood species used in the pergola: Cumaru, Angelim Vermelho, and an unidentified species. The wood strength class was determined by the resistograph, and biotic, abiotic, and structural damages were evaluated. The structural performance analysis, considering the actual sections and the physical and mechanical characteristics of the wood, was performed using SAP 2000 software, with the verification of structural elements and connections according to the Brazilian standard NBR 7190. The study concludes by presenting therapies of a constructive nature, treatment and protection, and structural character.

현대 판타지 웹소설 흥행요인 분석: 『재벌집 막내아들』 사례를 중심으로

In this paper, we will analyze the main box office factors of modern fantasy web novels. Regression, inscription, and reincarnation motifs are narrative structures frequently applied in modern fantasy web novels and are the biggest features that distinguish them from pure literature. In addition, the attractive protagonist is one of the core elements of the web novel and determines the overall flow of the work, and the reader feels strong surrogate satisfaction with the protagonist's narrative, role, and growth process. Therefore, this study comprehensively explores the unique narrative structure and protagonist characters found in modern fantasy web novels and analyzes their influence on their works. Based on the literature survey, a case study was conducted to promote an in-depth understanding of specific cases. The subject of this paper, “The Youngest Son of a Chaebol House,” is a modern fantasy web novel by Sankyung author who applies the regression code, which is the box office formula of web novels, and sets the modern and contemporary history of Korea, and has gained explosive popularity in Munpia from the beginning of publication, and refers to a chart arranged in the order of the highest number of views per day (24 hours) from 1st to 103rd (PC) and 107th (mobile) when clicking “Best” on today's best web novel platform Munpia. It is a work that has never missed the top spot. Based on this popularity, it was aired as a weekend mini-series on JTBC in 2022, and was selected as a research case for this study as a monumental work that achieved the highest box office success due to the success of modern fantasy web novels. The purpose of this study is to analyze the narrative structure that readers are enthusiastic about and how the main character is built and consumed in web novels where commerciality is paramount. Through this study, we would like to present and analyze typical narrative structures and main characteristics that are mainly shown in modern fantasy web novels. Through this analysis, it is expected that it will be possible to derive an understanding of how to increase the readers' immersion and to empathize with and coexist with the main character to further increase the attractiveness of modern fantasy web novel works.

A carboxymethyl cellulase from the yeast Cryptococcus gattii WM276: Expression, purification and characterisation

Cryptococcus gattii and its medical implications have been extensively studied. There is, however, a significant knowledge gap regarding cryptococcal survival in its environmental niche, namely woody material, which is glaring given that infection is linked to environmental populations. A gene from C. gattii (WM276), the predominant global molecular type (VGI), has been sequenced and annotated as a putative cellulase. It is therefore, of both medical and industrial intertest to delineate the structure and function of this enzyme. A homology model of the enzyme was constructed as a fusion protein to a maltose binding protein (MBP). The CGB_E4160W gene was overexpressed as an MBP fusion enzyme in Escherichia coli T7 cells and purified to homogeneity using amylose affinity chromatography. The structural and functional character of the enzyme was investigated using fluorescence spectroscopy and enzyme activity assays, respectively. The optimal enzyme pH and temperature were found to be 6.0 and 50 °C, respectively, with an optimal salt concentration of 500 mM. Secondary structure analysis using Far-UV CD reveals that the MBP fusion protein is primarily α-helical with some β-sheets. Intrinsic tryptophan fluorescence illustrates that the MBP-cellulase undergoes a conformational change in the presence of its substrate, CMC-Na+. The thermotolerant and halotolerant nature of this particular cellulase, makes it useful for industrial applications, and adds to our understanding of the pathogen's environmental physiology.

Measuring the impact of plot types on physical change: A diachronic analysis of urban form evolution in New York, Melbourne and Barcelona

Plots are hypothesised as the most influential determinant of urban form evolution yet remain understudied. Existing morphological studies exploring plots' influential role lack quantitative methods, while more recent quantitative urban form studies remain largely synchronic, analysing urban form at a single timeframe without offering diachronic frameworks. Addressing this gap, we investigate the relationship between plot types and physical change in three international case studies (New York, Melbourne and Barcelona) over two centuries. Employing a novel longitudinal spatial database generated from historical maps, we present a methodology to measure the configurational character of plot structures and identify multi-variable plot typologies using k-means clustering. Statistical analysis of the relation between plot types and physical change reveals that finer-grained, narrower, and more compact plot types exhibit significantly greater resistance to building replacement compared to coarser-grained, broader, and less compact plot types. Our findings demonstrate the robustness of plot structures' configurational character in explaining physical change dynamics in cities. These data-driven findings can guide policymakers in strategic land subdivision decisions to guide future preservation and development needs and patterns, ultimately promoting more resilient and adaptive urban environments.

Species designation requires new name for Gulf of Mexico marsh crab, restricting Sesarma reticulatum (Say, 1817) to the Atlantic seaboard of North America (Decapoda, Sesarmidae)

Abstract Long regarded to represent an undescribed species related to Sesarma reticulatum, warm-temperate populations of a common marsh crab from the Gulf of Mexico are herewith formally named Sesarma schubarti sp. nov. Records of S. reticulatum s. s. are restricted to the U.S. Atlantic seaboard from the Woods Hole region of Massachusetts to the Indian River region on the east coast of Florida. A diverse body of supportive evidence to underpin this separation has accrued over three decades, including previous observations based on physiology, ecology, reproduction, blood hemocyanin proteins, isozymes, and mtDNA sequences. Comparative morphological studies provide only minor structural characters to distinguish the new species from its Atlantic seaboard counterpart, including differences in the shape of the mature male first gonopod tip and positioning of a transverse crest on the male first pleonite. However, in fresh specimens colouration also differs, often strikingly so. Body surfaces that are variously purplish in mature specimens of S. reticulatum s. s., yielding the common name “purple marsh crab”, are instead more commonly reddish to orange in S. schubarti sp. nov. Our analysis of new 16S and COI gene sequences, along with existing genetic data, clarifies relationships of the new species to both S. reticulatum s. s. and S. curacaoense. The new species is formally named in honor of the late Christoph D. Schubart, a cherished colleague who contributed extensively to knowledge of sesarmid and other brachyuran crabs over his unfortunately abbreviated career.

Plastome structure and phylogenetic relationships of genus Hydrocotyle (apiales): provide insights into the plastome evolution of Hydrocotyle

BackgroundThe genus Hydrocotyle Tourn. ex L. is a key group for further study on the evolution of Apiales, comprising around 170 species globally. Previous studies mainly focused on separate sections and provided much information about this genus, but its infrageneric relationships are still confusing. In addition, the genetic basis of its adaptive evolution remains poorly understood. To investigate the phylogeny and evolution of the genus, we selected ten representative species covering two of three diversity distribution centers and exhibiting rich morphology diversity. Comparative plastome analysis was conducted to clarify the structural character of Hydrocotyle plastomes. Positive selection analyses were implemented to assess the evolution of the genus. Phylogenetic inferences with protein-coding sequences (CDS) of Hydrocotyle and 17 related species were also performed.ResultsPlastomes within Hydrocotyle were generally conservative in structure, gene order, and size. A total of 14 regions (rps16-trnK, trnQ-rps16, atpI-atpH, trnC-petN-psbM, ycf3-trnS, accD-psaI-ycf4, petA-psbJ, rps12-rpl20, rpl16 intron, rps3-rpl16 intron, rps9-rpl22, ndhF-rpl32, ndhA intron, and ycf1a) were recognized as hotspot regions within the genus, which suggested to be promising DNA barcodes for global phylogenetic analysis of Hydrocotyle. The ycf15 gene was suggested to be a protein-coding gene for Hydrocotyle species, and it could be used as a DNA barcode to identify Hydrocotyle. In phylogenetic analysis, three monophyletic clades (Clade I, II, III) were identified with evidence of rapid radiation speciation within Clade I. The selective pressure analysis detected that six CDS genes (ycf1b, matK, atpF, accD, rps14, and psbB) of Hydrocotyle species were under positive selection. Within the genus, the last four genes were conservative, suggesting a relation to the unique evolution of the genus in Apiales. Seven genes (atpE, matK, psbH, ycf1a, ycf1b, rpoA, and ycf2) were detected to be under some degree of positive selection in different taxa within the genus Hydrocotyle, indicating their role in the adaptive evolution of species.ConclusionsOur study offers new insights into the phylogeny and adaptive evolution of Hydrocotyle. The plastome sequences could significantly enhance phylogenetic resolution and provide genomic resources and potential DNA markers useful for future studies of the genus.

Understanding Newton's Third Law: A Study of Prospective Physics Teachers' Knowledge Structure

This research aims to explore the ability to understand concepts and the characteristics of the knowledge structure of prospective physics teachers regarding Newton's Third Law. This research was conducted on 26 Physics Education students in their first year who had received material on Newton's Laws. The instrument used is the Force Concept Inventory (FCI) test instrument. Using four multiple-choice questions accompanied by reasons, the quantitative data source comes from students' choice of answers. In contrast, the qualitative data source comes from students' reasons for choosing answers, which are used to see the characteristics of knowledge structures. The data analysis technique used is descriptive statistics to present a picture of the ability to understand concepts and the level of character of the knowledge structure of prospective teachers. The results show that the concept understanding ability of prospective physics teachers has an average of 67.31 and is classified as sufficient. The knowledge structure characteristics of prospective physics teachers at the expert level is 62.50%, the beginner level is 14.42%, and the intermediate level is 24.04%. These results show that the ability to understand the concept of Newton's Third Law and the characteristics of knowledge structures have a coherent influence. Prospective teachers with the characteristics of an expert knowledge structure can solve physics problems using correct physics principles. These findings require further research to explore the factors influencing understanding concepts and characteristics of prospective teachers' knowledge structures and more effective teaching strategies.

Cultural MemoryA Dream of Red Mansions

This paper applies the theory of cultural memory, proposed by Jan Assmann, to the study of the Chinese classical novel A Dream of Red Mansions. The first part of this paper introduces the historical development of Cultural Memory theory and its features. In the second part of the paper, it applies Cultural Memory theory to the narrative structure and novel characters research of A Dream of Red Mansions. Through analysis, the complexity and inherent contradictions in the narrative structure of A Dream of Red Mansions provide evidence for the hypothesis that A Dream of Red Mansions is a combination of Mirror for The Romantic and The Story of Stone. A Dream of Red Mansions may have more than one author, besides Cao Xueqin, another author is Cao Xueqin's elder, who experienced the rise and fall of the Cao family firsthand. This also explains the contradictions in the character images in A Dream of Red Mansions, especially the persona of Jia Baoyu, which consisted of the authors' life experience and ideal personality. The novel A Dream of Red Mansions has a dual nature of cultural memory.

Relationships Among the Bryophytes and Vascular Plants: A Case Study in Deep-Time Reconstruction

Relationships of the three bryophyte lineages (liverworts, mosses, and hornworts) to vascular plants is a pivotal question in the study of the origin and evolution of land plants. In recent decades, this question has been subjected to intense phylogenetic analyses using morphological characters, multigene DNA sequences, and genome structural characters. A tentative consensus, reached ten years ago, suggested that bryophytes are a paraphyletic group, with liverworts being sister to all other land plants and hornworts being sister to vascular plants. However, several more recent nuclear phylogenomic studies have concluded that bryophytes represent a monophyletic group that is sister to vascular plants. A discussion is presented here on strengths and weaknesses of different types of characters (morphological traits, nucleotide sequences, and genome structural arrangements) and their suitability for resolving deep phylogenetic relationships. Moreover, several criteria for credible phylogenetic reconstruction are proposed. Strong statistical support for reconstructed relationships should be derived from high-quality, independent characters selected for suitability to the particular question being addressed. The relationships inferred in a study should be congruent with those from as many other lines of phylogenetic evidence as possible. Any incongruities should be explicable by well-understood biological mechanisms. It is concluded that the relationships of the three bryophyte lineages to vascular plants should currently be viewed as unresolved. This is a difficult phylogenetic problem; the land plants underwent a rapid radiation a long time ago. Yet, further exploration of analytical methods and careful choice of characters should lead to the eventual elucidation of diversification patterns among early land plants.

Self-Healing and Recyclable Polyurethane/Nanocellulose Elastomer Based on the Diels-Alder Reaction.

With the background of the fossil fuel energy crisis, the development of self-healing and recyclable polymer materials has become a research hotspot. In this work, a kind of cross-linking agent with pendent furan groups was first prepared and then used to produce the Polyurethane elastomer based on Diels-Alder chemistry (EPU-DA). In addition, in order to further enhance the mechanical properties of the elastomer, cellulose nanofibers (CNFs) were added into the Polyurethane system to prepare a series of composites with various contents of CNF (wt% = 0.1~0.7). Herein, the FTIR and DSC were used to confirm structure and thermal reversible character. The tensile test also indicated that the addition of CNF increased the mechanical properties compared to the pure Polyurethane elastomer. Due to their reversible DA covalent bonds, the elastomer and composites were recycled under high-temperature conditions, which extends Polyurethane elastomers' practical applications. Moreover, damaged coating can also be repaired, endowing this Polyurethane material with good potential for application in the field of metal protection.