Typical Domain Structure Research Articles

Mapping Sliding Ferroelectricity in Bulk (PbS)1.11VS2 Crystals

The recent discovery of sliding ferroelectricity opens up the field of 2D ferroelectricity. However, the limitation to switching the polarization due to the topological protection of the domain walls limits the potential of these heterostructures. Here, the switching of sliding ferroelectric bulk misfit layer compound (PbS)1.11VS2 crystals is studied using switching spectroscopy piezoresponse force microscopy. A large number of measured hysteresis loops can be efficiently analyzed using unsupervised machine‐learning tools. Different switching behavior of the domains is observed on different types of domain structures, and it is shown that full domain switching can be observed for the right type of dislocation structure in the PbS layer.

Collective control of a vortex array in a ferroelectric ultrathin film

Recently, the observation of ferroelectric vortex arrays has triggered the investigation of topological domain structures and their characteristics. Vortices are typical topological domain structures with chirality in nanoscale ferroelectric materials. The chirality of a single vortex in a nanodot can be easily manipulated, but the collective control of a vortex array is exceptionally difficult and has not yet been realized. This Letter proposes an effective scheme for the collective control of a vortex array and investigates it via phase-field simulations. The results indicate that the collective control of a vortex array with bidirectional switching can be realized by introducing a bending film with periodic large curvatures under alternative electric fields. Furthermore, a general rule for determining the electrically controllable chirality of ferroelectric vortices is proposed. This Letter demonstrates the feasibility of the collective control of vortex arrays and provides insights for developing ferroelectric nanoelectronic devices based on vortex arrays.

Cloning and Characterization of Chitin Deacetylase from Euphausia superba.

Chitin deacetylase (CDA) can catalyze the deacetylation of chitin to produce chitosan. In this study, we identified and characterized a chitin deacetylase gene from Euphausia superba (EsCDA-9k), and a soluble recombinant protein chitin deacetylase from Euphausia superba of molecular weight 45 kDa was cloned, expressed, and purified. The full-length cDNA sequence of EsCDA-9k was 1068 bp long and encoded 355 amino acid residues that contained the typical domain structure of carbohydrate esterase family 4. The predicted three-dimensional structure of EsCDA-9k showed a 67.32% homology with Penaeus monodon. Recombinant chitin deacetylase had the highest activity at 40 °C and pH 8.0 in Tris-HCl buffer. The enzyme activity was enhanced by metal ions Co2+, Fe3+, Ca2+, and Na+, while it was inhibited by Zn2+, Ba2+, Mg2+, and EDTA. Molecular simulation of EsCDA-9k was conducted based on sequence alignment and homology modeling. The EsCDA-9k F18G mutant showed a 1.6-fold higher activity than the wild-type enzyme. In summary, this is the first report of the cloning and heterologous expression of the chitin deacetylase gene in Euphausia superba. The characterization and function study of EsCDA-9k will serve as an important reference point for future application.

Effect of electrical boundary conditions on the domain stability of porous ferroelectric nanowires

The electrical boundary condition plays an important role in the manipulation of domain structures in low-dimensional ferroelectric materials, especially ferroelectric nanowires. Here, using phase-field simulations, we systematically investigate the influence of electrical boundary conditions on the domain structure in porous PbTiO3 ferroelectric nanowires. Our results demonstrate the formation of four types of domain structures via varying electrical boundary conditions, which possess distinguished local polarization and energy configurations. We further show that the domain structures are also dependent on the nanowire radius, including the breakdown of a metastable concentric toroidal domain structure upon reducing the radius to 14 nm. The present work provides guidance for further experimental studies on the control of polar domain structures through manipulating the electrical boundary condition and the ferroelectric size, which paves the way for developing multi-functions of low-dimensional ferroelectric systems.

Regulation of Cell Proliferation and Nrf2-Mediated Antioxidant Defense: Conservation of Keap1 Cysteines and Nrf2 Binding Site in the Context of the Evolution of KLHL Family.

Keap1 (Kelch-like ECH-associated protein 1) is one of the major negative regulators of the transcription factor Nrf2 (nuclear factor erythroid-2-related factor 2), which induces the expression of numerous proteins defending the cell against different stress conditions. Keap1 is generally negatively regulated by post-translational modification (mostly via its cysteine residues) and interaction with other proteins that compete with Nrf2 for binding. Cysteine residues in Keap1 have different effects on protein regulation, as basic residues (Lys, Arg, and His) in close proximity to them increase cysteine modification potential. In this paper, we present an evolutionary analysis of residues involved in both mechanisms of Keap1 regulation in the broader context of the KLHL protein family in vertebrates. We identified the typical domain structure of the KLHL protein family in several proteins outside of this family (namely in KBTBD proteins 2, 3, 4, 6, 7, 8, 12 and 14). We found several cysteines that are flanked by basic residues (namely, C14, C38, C151, C226, C241, C273, C288, C297, C319, and C613) and, therefore, may be considered more susceptible to regulatory modification. The Nrf2 binding site is completely conserved in Keap1 in vertebrates but is absent or located in nonaligned DA and BC loops of the Kelch domain within the KLHL family. The development of specific substrate binding regions could be an evolutionary factor of diversification in the KLHL protein family.

Cloning and function analysis of DlWRKY9 gene in longan (Dimocarpus longan)

WRKY is one of the largest plant transcription factors (TFs) which is widely involved in plant growth, development, and responses to stresses. In the present study, a WRKY TF DlWRKY9 was cloned from longan (Dimocarpus longan). The coding sequence (CDS) of DlWRKY9 is 762 bp in length and encodes 253 amino acids. It has a typical WRKY domain and zinc finger structure which belongs to type IIa WRKY protein. The molecular weight of DlWRKY9 protein was 30.27kda and the theoretical isoelectric point (PI) was 5.24. It is an unstable hydrophilic protein. The secondary structure of DlWRKY9 protein consists of helical structure (17.39%), extended chain (8.70%) and other structures (turn and random coil) (73.91%). The amino acid sequence of DlWRKY9 protein had the highest similarity with DlWRKY9 (xp_006450293.1) of citrus Clementina. DlWRKY9 gene promoter elements contain light, abscisic acid, gibberellin, jasmonic acid and other response elements. The results of qRT-PCR showed that the relative expression level of DlWRKY9 gene in pericarp was higher, followed by young fruits and floral organs. Meanwhile, DlWRKY9 gene specifically down-regulated in the early stage of flower induction in ‘Sijimi’ (SJ) longan. The results of transient expression of Arabidopsis protoplasts showed that the fluorescence signal was mainly concentrated in the nucleus. Moreover, overexpression of DlWRKY9 in Arabidopsis promoted early flowering. These results provide useful information for revealing the biological roles of DlWRKY9 in longan and increase our understanding of the WRKY family in fruit trees.

Scheming the Political Landscape: A New Communist Domain

The paper analyses and interprets Western radical left-wing scholars’ view on communism from the three dimensions of Ego, Other and the World in the modern philosophical context. The purpose of the research is to compare and reconstruct the three scientific categories of relations represented by communism, namely, the logical dialectical relations of Ego domain, Other domain and the World domain. The theoretical reconstruction and contextual analysis of Jacques Lacan and Sigmund Freud’s psychoanalysis, as well as numerous researchers of their work are used. The methodological basis of this research is a philosophical reconstruction and deductive speculation, inductive speculation and insight speculation approach. It is shown that the radical left scholars reexamine the evolution of communism from three basic categories: imaginary domain, symbolic domain and real domain. Furthermore, they reconsider the construction of communism through the study of the interrelations among Ego, Other and the World. Simultaneously, they also excavate the structural contradiction of contemporary capitalism and criticise its deficiencies. The weaknesses of the argument about these relations are shown by reconstructing this upward spiral relations, which can be considered an ideal model of domain structure in ‘The Neo-Communist domain’. On the basis of this claim, it is shown that these three types of domain structures may well coexist at least in ideal society, thus mankind should adhere to Marx’s dialectical materialism to consider problems. The scientific significance of the research is justifying that the philosophical reconstruction does not only enrich Marxist communist ideology and is of great practical significance for Socialist countries to reshape the ideals and beliefs of Marxism, but also stick to the development of Marxism and to expand the research horizon of communism. Nevertheless, the communist thought of western radical left scholars still has the dilemma of separating theory from practice and failing to transform theoretical communism into combatant communism.

Molecular characterization and function of chitin deacetylase-like from the Chinese mitten crab, Eriocheir sinensis.

Chitin deacetylases are essential enzymes in the chitin-modifying process and play vital roles in arthropod molting. In this study, we identified and characterized a chitin deacetylase-like (EsCDA-l) gene in the Chinese mitten crab, Eriocheir sinensis. The open reading frame of EsCDA-l was 2555bp and encoded 554 amino acid residues that contained typical domain structure of carbohydrate esterase family 4. Phylogenetic analysis reveal that EsCDA-l belongs to the group I chitin deacetylase family. Quantitative real-time PCR analyses showed that EsCDA-l was highly expressed in exoskeletal tissues and megalopa stages. During the molting cycle, EsCDA-l was up-regulated periodically in the post-molt stage. Knockdown of EsCDA-l resulted in the abnormal ultrastructure of cuticle, prevented molting to high mortality suggesting EsCDA-l is indispensable for molting. The characterization and function analysis of the EsCDA-l should provide useful reference for further research on the utility of key genes involved in the chitin metabolic pathway in the molting process of the Chinese mitten crab as well as other crustaceans.

Transformation of initial domain structure by ac electric field in lithium tantalate crystals with composition gradient

A transformation of the initial three-layer domain structure in lithium tantalate with composition gradient and formation of charged domain wall (CDW) under application of ac electric field have been studied on the surface and in the bulk. We have demonstrated the abilities to produce several types of domain structure by ac field treatment: (1) a layer of the maze structure in the bulk with lower thickness and domain wall concentration, (2) a CDW situated just in the center of the plate, and (3) a decay of the initial domain structure leading to formation of large through domains.

Genome-wide identification of Cellulose-like synthase D gene family in Dendrobium catenatum

Dendrobium catenatum, which grows on the semi humid rocks in the mountains, has been at the top of the ‘Nine Immortals of China’ since ancient times. It is a kind of yin tonic medicine and its main active component is polysaccharide. Cellulose synthase-like D(CslD) genes were predicted to catalyse the biosynthesis of 1,4-β-d-glycan backbone of hemicelluloses, which plays fundamental roles in plant development. To investigate the role of CslD in the development of D. catenatum, eight CslD genes (DcCslD1,2a,2b,3a,3b,4a,4b,5) were identified. The results of protein prediction and analysis showed that CslD2a/2b/4a/4b proteins were acidic proteins. All the proteins had obvious hydrophobic or hydrophilic regions, and had transmembrane structure. Phylogenetic analysis revealed that the DcCslD family could be divided into group I, II, III and IV. DcCslD proteins had a typical Cellulose synthase domain and similar protein structures to the CslDs of other plants. Their promoter regions contain cis regulatory elements related to stress and hormone response. The results of qRT-PCR showed that the identified DcCslDs were differentially expressed in roots, stems and leaves. Most of them were highly expressed in stems and leaves. The environmental stresses examination showed that the expression levels of DcCslD5 were closely associated with drought-recovery treatment; the expression levels of DcCslD1, DcCslD2a, DcCslD2b, DcCslD3a and DcCslD5 were significantly influenced by low temperature. This study systematically analyzed the sequence characteristics of CslD protein of D. catenatum, which can provide reference for further study on the function of CslD protein in the polysaccharide metabolism of D. catenatum. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1941252.

Evolution of domain structure in Fe3GeTe2 * *Project supported by the National Key R&D Program of China (Grant Nos. 2017YFA0206202 and 2019YFA0308000), the National Natural Science Foundation of China (Grant Nos. 51871130, 62022089, and 11874405), and the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2019007).

Two-dimensional (2D) magnets provide an ideal platform to explore new physical phenomena in fundamental magnetism and to realize the miniaturization of magnetic devices. The study on its domain structure evolution with thickness is of great significance for better understanding the 2D magnetism. Here, we investigate the magnetization reversal and domain structure evolution in 2D ferromagnet Fe3GeTe2 (FGT) with a thickness range of 11.2–112 nm. Three types of domain structures and their corresponding hysteresis loops can be obtained. The magnetic domain varies from a circular domain via a dendritic domain to a labyrinthian domain with increasing FGT thickness, which is accompanied by a transition from squared to slanted hysteresis loops with reduced coercive fields. These features can be ascribed to the total energy changes from exchange interaction-dominated to dipolar interaction-dominated with increasing FGT thickness. Our finding not only enriches the fundamental magnetism, but also paves a way towards spintronics based on 2D magnet.

Lattice and magnetic dynamics in the polar, chiral, and incommensurate antiferromagnet Ni2InSbO6

Complex systems with coexisting polarity, chirality and incommensurate magnetism are of great interest because they open new degrees of freedom in interaction between different subsystems and therefore they host a plethora of intriguing physical properties. Here we report on optical properties and lattice and spin dynamics of Ni$_2$InSbO$_6$ single crystals studied with the use of polarized optical microscopy and micro-Raman spectroscopy in the temperature range 10-300 K. Ni$_2$InSbO$_6$ crystallizes in a polar structure described by the noncentrosymmetric space group R3 and two types of structural domains were visualized due to natural optical activity of opposite chirality. Raman tensor elements of most A and E phonons along with their symmetry were determined. The manifestation of LO-TO splitting was observed for the A modes. By tracking the temperature dependencies of phonon frequencies the well pronounced spin-phonon interaction was observed for several modes below and above the N\'eel transition temperature TN = 76 K. In antiferromagnetic phase a wide excitation centred at 247 cm-1 was detected and assigned to the two-magnon mode and this value was used for estimating exchange parameters through linear spin-wave theory calculations.

Chitin deacetylase 1 and 2 are indispensable for larval-pupal and pupal-adult molts in Heortia vitessoides (Lepidoptera: Crambidae).

Heortia vitessoides Moore is a notorious defoliator of Aquilaria sinensis (Lour.) Gilg trees. Chitin deacetylases (CDAs) catalyze the N-deacetylation of chitin, which is a crucial process for chitin modification. Here, we identified and characterized HvCDA1 and HvCDA2 from H. vitessoides. HvCDA1 and HvCDA2 possess typical domain structures of CDAs and belong to the Group I CDAs. HvCDA1 and HvCDA2 were highly expressed before and after the larval-larval molt. In addition, both exhibited relatively high mRNA expression levels during the larval-pupal molt, the pupal stage, and the pupal-adult molt. HvCDA1 and HvCDA2 transcript expression levels were highest in the body wall and relatively high in the larval head. Significant increases in the HvCDA1 and HvCDA2 transcript expression levels were observed in the larvae upon exposure to 20-hydroxyecdysone. RNA interference-mediated HvCDA1 and HvCDA2 silencing significantly inhibited HvCDA1 and HvCDA2 expression, with abnormal or nonviable phenotypes being observed. Post injection survival rates of the larvae injected with dsHvCDA1 and dsHvCDA2 were 66.7% and 46.7% (larval-pupal) during development and 23.0% and 6.7% (pupal-adult), respectively. These rates were significantly lower than those of the control group insects. Our results suggest that HvCDA1 and HvCDA2 play important roles in the larval-pupal and pupal-adult transitions and represent potential targets for the management of H. vitessoides.

Identification and Expression Analysis of Four Small Heat Shock Protein Genes in Cigarette Beetle, Lasioderma serricorne (Fabricius).

Small heat shock proteins (sHsps) are molecular chaperones that play crucial roles in the stress adaption of insects. In this study, we identified and characterized four sHsp genes (LsHsp19.4, 20.2, 20.3, and 22.2) from the cigarette beetle, Lasioderma serricorne (Fabricius). The four cDNAs encoded proteins of 169, 180, 181, and 194 amino acids with molecular weights of 19.4, 20.2, 20.3, and 22.2 kDa, respectively. The four LsHsp sequences possessed a typical sHsp domain structure. Quantitative real-time PCR analyses revealed that LsHsp19.4 and 20.3 transcripts were most abundant in pupae, whereas the transcript levels of LsHsp20.2 and 22.2 were highest in adults. Transcripts of three LsHsp genes were highly expressed in the larval fat body, whereas LsHsp20.2 displayed an extremely high expression level in the gut. Expression of the four LsHsp genes was dramatically upregulated in larvae exposed to 20-hydroxyecdysone. The majority of the LsHsp genes were significantly upregulated in response to heat and cold treatments, while LsHsp19.4 was insensitive to cold stress. The four genes were upregulated when challenged by immune triggers (peptidoglycan isolated from Staphylococcus aureus and from Escherichia coli 0111:B4). Exposure to CO2 increased LsHsp20.2 and 20.3 transcript levels, but the LsHsp19.4 transcript level declined. The results suggest that different LsHsp genes play important and distinct regulatory roles in L. serricorne development and in response to diverse stresses.

Formation of the quasi-regular stripe nanodomain structures in lithium tantalate by scanning laser heating

The domain structure formation in the congruent lithium tantalate single crystals after IR laser irradiation by linear scanning of Z + polar surface has been studied. Two types of domain structures have been revealed experimentally: self-similar structure and quasi-regular stripe structure. The statistical processing has shown that the increase in the scanning velocity leads to increase in the area with stripe domain structure and to decrease in the average domain period. At the maximum scanning velocity 4.8 m/s, the quasi regular domain stripe structure with average period 0.8 μm has been obtained over the 70% of the switched area.

Microwave Directional Dichroism Resonant with Spin Excitations in the Polar Ferromagnet GaV_{4}S_{8}.

We have investigated the directional dichroism of magnetic resonance spectra in the polar ferromagnet GaV_{4}S_{8}. While four types of structural domains are energetically degenerated under a zero field, the magnetic resonance for each domain is well separated by applying magnetic fields due to uniaxial magnetic anisotropy. Consequently, a directional dichroism as large as 20% is clearly observed without domain cancellation. The present observation therefore demonstrates that not only magnetoelectric monodomain crystals but also magnetoelectric multidomain specimens can be used to realize microwave (optical) diodes owing to the lack of inversion domains.

Three-dimensional analysis reveals altered chromatin interaction by enhancer inhibitors harbors TCF7L2-regulated cancer gene signature.

Distal regulatory elements influence the activity of gene promoters through chromatin looping. Chromosome conformation capture (3C) methods permit identification of chromatin contacts across different regions of the genome. However, due to limitations in the resolution of these methods, the detection of functional chromatin interactions remains a challenge. In the current study, we employ an integrated approach to define and characterize the functional chromatin contacts of human pancreatic cancer cells. We applied tethered chromatin capture to define classes of chromatin domains on a genome-wide scale. We identified three types of structural domains (topologically associated, boundary, and gap) and investigated the functional relationships of these domains with respect to chromatin state and gene expression. We uncovered six distinct sub-domains associated with epigenetic states. Interestingly, specific epigenetically active domains are sensitive to treatment with histone acetyltransferase (HAT) inhibitors and decrease in H3K27 acetylation levels. To examine whether the subdomains that change upon drug treatment are functionally linked to transcription factor regulation, we compared TCF7L2 chromatin binding and gene regulation to HAT inhibition. We identified a subset of coding RNA genes that together can stratify pancreatic cancer patients into distinct survival groups. Overall, this study describes a process to evaluate the functional features of chromosome architecture and reveals the impact of epigenetic inhibitors on chromosome architecture and identifies genes that may provide insight into disease outcome.

Multiple Roles of Tenascins in Homeostasis and Pathophysiology of Aorta.

Tenascins are a family of large extracellular matrix (ECM) glycoproteins. Four family members (tenascin-C, -R, -X, and -W) have been identified to date. Each member consists of the same types of structural domains and exhibits time- and tissue-specific expression patterns, suggesting their specific roles in embryonic development and tissue remodeling. Among them, the significant involvement of tenascin-C (TNC) and tenascin-X (TNX) in the progression of vascular diseases has been examined in detail. TNC is strongly up-regulated under pathological conditions, induced by a number of inflammatory mediators and mechanical stress. TNC has diverse functions, particularly in the regulation of inflammatory responses. Recent studies suggest that TNC is involved in the pathophysiology of aneurysmal and dissecting lesions, in part by protecting the vascular wall from destructive mechanical stress. TNX is strongly expressed in vascular walls, and its distribution is often reciprocal to that of TNC. TNX is involved in the stability and maintenance of the collagen network and elastin fibers. A deficiency in TNX results in a form of Ehlers–Danlos syndrome (EDS). Although their exact roles in vascular diseases have not yet been elucidated, TNC and TNX are now being recognized as promising biomarkers for diagnosis and risk stratification of vascular diseases.

Characterization of a β-N-acetylglucosaminidase gene and its involvement in the development of Lasioderma serricorne (Fabricius)

β-N-acetylglucosaminidases (NAGs) are essential enzymes in the chitin degradation process and play important roles in insect molting and metamorphosis. In this study, we identified and characterized a full-length cDNA of NAG1 (LsNAG1) in the cigarette beetle, Lasioderma serricorne (Fabricius). The open reading frame of LsNAG1 was 1821 bp and encoded 606 amino acid residues that contained typical domain structure of NAGs. Phylogenetic analyses suggested that the deduced protein LsNAG1 was orthologous to another insect group I NAGs. Quantitative real-time PCR confirmed that LsNAG1 expression levels peaked periodically in the late larval and late pupal stages. A significantly increased level of LsNAG1 transcripts was observed in larvae exposed to the steroid hormone 20-hydroxyecdysone (20E), indicating LsNAG1 was responsive to 20E. Injection of double-stranded RNA (dsRNA) of LsNAG1 into 4th instar larvae and late pupae significantly reduced LsNAG1 transcript levels in both stages, and led to severe molting defects and high mortality. Compared with the control insects injected with dsGFP, 48% and 83% of the larvae and pupae injected with dsLsNAG1, respectively, died during or soon after molting to the next stage. These results demonstrate that LsNAG1 may play a crucial role in successful larval–pupal and pupal–adult transitions, and could be used as an efficient novel target for storage pest control.

Functional characterization of chitin deacetylase 1 gene disrupting larval-pupal transition in the drugstore beetle using RNA interference.

Chitin deacetylases (CDAs) are chitin degradation enzymes that strictly regulate growth and development in insects. In this study, we identified and characterized a full-length cDNA of the CDA gene (SpCDA1) in the drugstore beetle, Stegobium paniceum. The open reading frame of SpCDA1 (1614 bp) encoded a 537 amino acid protein, which possessed typical domain structures of CDAs. Phylogenetic comparison to other insect CDAs revealed that SpCDA1 belongs to Group Ib CDAs. Quantitative real-time PCR analyses showed that SpCDA1 was highly expressed in late larval stages. Significant increase of SpCDA1 transcript level in the larvae was observed upon the exposure of 20-hydroxyecdysone. Injection of double-stranded RNA (dsRNA) of SpCDA1 into the late larvae significantly reduced SpCDA1 transcript levels, resulted in larval-pupal molting difficulty and produced high larval mortality. After 15 days, the survival rate of S. paniceum in dsSpCDA1 group was significantly reduced by 72% compared to the control. The results demonstrated that SpCDA1 is essential for successful larval-pupal transition in S. paniceum and this gene may be a potential target for pest control.