Atomic-Limit Mott Insulator in [4]Triangulene Frameworks.

Triangulene, one unique class of zigzag-edged triangular graphene molecules, has attracted tremendous research interest. In this work, as an ultimate phase of the Mott insulator, we present the realization of the atomic-limit Mott insulator in experimentally synthesized [4]triangulene frameworks ([4]-TGFs) from first-principles calculations. The frontier molecular orbitals of the nonmagnetic [4]triangulene consist of three coupled corner modes. After the isolated [4]triangulene is assembled into [4]-TGF, one special enantiomorphic flat band is created through the coupling of these corner modes, which is identified to be a second-order topological insulator with half-filled topological corner states at the Fermi level. Moreover, [4]-TGF prefers an antiferromagnetic ground state under Hubbard interactions, which further splits these metallic zero-energy states into an atomic-limit Mott insulator with spin-polarized corners. Since the fractional filling of topological corner states is a smoking-gun signature of higher-order topology, our results demonstrate a universal approach to explore the atomic-limit Mott insulators in higher-order topological materials.

Experimental Demonstration of Topological Catalysis for CO2 Electroreduction.

The past decade has witnessed substantial progress in understanding nontrivial band topology and discovering exotic topological materials in condensed-matter physics. Recently, topological physics has been further extended to the chemistry discipline, leading to the emergence of topological catalysis. In principle, the topological effect is detectable in catalytic reactions, but no conclusive evidence has been reported yet. Herein, by precisely manipulating the topological surface state (TSS) of Bi2Se3 nanosheets through thickness control and the application of a magnetic field, we provide direct experimental evidence to illustrate topological catalysis for CO2 electroreduction. With and without the cooperation of TSS, CO2 is mainly reduced into liquid fuels (HCOOH and H2C2O4) and CO, exhibiting high (up to 90% at -1.1 V versus reversible hydrogen electrode) and low Faradaic efficiency (FE), respectively. Theoretically, the product and FE difference can be attributed to the TSS-regulated adsorption of key intermediates and the reduced barrier of the potential-determining step. Our work demonstrates the inherent correlation between band topology and electrocatalysis, paving a new avenue for designing high-performance catalysts.

Facilely Modified Nickel-Based Hole Transporting Layers for Organic Solar Cells with 19.12% Efficiency and Enhanced Stability.

Hole transporting layers (HTLs), strategically positioned between electrode and light absorber, play a pivotal role in shaping charge extraction and transport in organic solar cells (OSCs). However, the commonly used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, with its hygroscopic and acidic nature, undermines the operational durability of OSC devices. Herein, an environmentally friendly approach is developed utilizing nickel acetate tetrahydrate (NiAc·4H2O) and [2-(9H-carbazol-9-yl)ethyl] phosphonic acid (2PACz) as the NiAc·4H2O/2PACz HTL, aiming at overcoming the limitations posed by the conventional PEDOT:PSS one. Encouragingly, a remarkable power conversion efficiency (PCE) of 19.12% is obtained for the OSCs employing NiAc·4H2O/2PACz as the HTL, surpassing that of devices with the PEDOT:PSS HTL (17.59%), which is ranked among the highest ones of OSCs. This improvement is attributed to the appropriate work function, enhanced hole mobility, facilitated exciton dissociation efficiency, and lower recombination loss of NiAc·4H2O/2PACz-based devices. Furthermore, the NiAc·4H2O/2PACz-based OSCs exhibit superior operational stability compared to their PEDOT:PSS-based counterparts. Of significant note, the NiAc·4H2O/2PACz HTL demonstrates a broad generality, boosting the PCE of the PM6:PY-IT and PM6:Y6-based OSCs from 16.47% and 16.79% (with PEDOT:PSS-based analogs as HTLs) to 17.36% and 17.57%, respectively. These findings underscore the substantial potential of the NiAc·4H2O/2PACz HTL in advancing OSCs, offering improved performance and stability, thereby opening avenue for highly efficient and reliable solar energy harvesting technologies.

LINC00624 affects hepatocellular carcinoma proliferation and apoptosis through the miR-342-3p/DNAJC5 axis.

LINC00624 is a long noncoding RNA (lncRNA) which was seldom investigated before. The goal of our study is to clarify the expression and underlying network of LINC00624 in hepatocellular carcinoma (HCC). Here, both HCC and normal living cell lines were employed. Real-time quantitative PCR and western blot were used to determine the pattern of genes and proteins. Colony formation, flow cytometry and western blot tests were used to determine cell proliferation and apoptosis, respectively. Dual luciferase was used to verify molecule-molecule interactions. LINC00624 expression was increased in HCC cell lines and miR-342-3p was decreased. Elimination of LINC00624 increased proliferation while decreasing cell apoptosis. LINC00624 acted as a molecular sponge for miR-342-3p, hence facilitating DNAJC5 expression. Functional tests demonstrated that miR-342-3p suppression could reverse the effect of LINC00624 silence and overexpression of DNAJC5 significantly mitigated the biological consequences of miR-342-3p. These finding demonstrated that LINC00624 aggravated HCC progression by modulating proliferation and apoptosis via targeting miR-342-3p/DNAJC5 axis. These data support that inhibition of LINC00624 may a potential treatment strategies of HCC.

Pseudospin Polarized Dual-Higher-Order Topology in Hydrogen-Substituted Graphdiyne.

Although the topological band theory is applicable to both Fermionic and bosonic systems, the same electronic and phononic topological phases are seldom reported in one natural material. In this work, we show the presence of a dual-higher-order topology in hydrogen-substituted graphdiyne (H-GDY) by first-principles calculations. The intriguing enantiomorphic flat-bands are realized in both electronic and phononic bands of H-GDY, which is confirmed to be an organic 2D second-order topological insulator (SOTI). Most importantly, we found that the topological corner states are pseudospin polarized in H-GDY, exhibiting a clockwise or counterclockwise texture perpendicular to the radial direction. Our results not only identify the existence of the dual-higher-order topology in covalent organic frameworks but also uncover a unique pseudospin polarization-coordinate locking relation, further extending the well-known spin-momentum locking relation in conventional topological insulators.

Synthesizing Cr-Based Two-Dimensional Conjugated Metal-Organic Framework Through On-Surface Substitution Reaction.

A single-layer Cr3 (HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) conjugated metal-organic framework (c-MOF) is synthesized under ultrahigh vacuum conditions by substituting Cr for Ni in Ni3 (HITP)2 template. As revealed by low-temperature scanning tunneling microscopy and scanning tunneling spectroscopy, while codeposition of Cr atoms and 2,3,6,7,10,11-hexaaminotriphenylene precursors produces irregular branches, crystalline Cr3 (HITP)2 frameworks are obtained by depositing Cr atoms to the Ni3 (HITP)2 templates. The density functional theory calculations reveal that the binding energy between Cr and HITP ligands is much higher than that for Ni, which hampers the growth of crystalline Cr3 (HITP)2 frameworks through direct coordination assembly but makes the substitution reaction energetically favorable. This work demonstrates a new strategy to prepare high-quality early-transition-metal-based c-MOFs under ultrahigh vacuum conditions.

Magnetotransport signatures of Weyl physics and discrete scale invariance in the elemental semiconductor tellurium.

The study of topological materials possessing nontrivial band structures enables exploitation of relativistic physics and development of a spectrum of intriguing physical phenomena. However, previous studies of Weyl physics have been limited exclusively to semimetals. Here, via systematic magnetotransport measurements, two representative topological transport signatures of Weyl physics, the negative longitudinal magnetoresistance and the planar Hall effect, are observed in the elemental semiconductor tellurium. More strikingly, logarithmically periodic oscillations in both the magnetoresistance and Hall data are revealed beyond the quantum limit and found to share similar characteristics with those observed in ZrTe5 and HfTe5 The log-periodic oscillations originate from the formation of two-body quasi-bound states formed between Weyl fermions and opposite charge centers, the energies of which constitute a geometric series that matches the general feature of discrete scale invariance (DSI). Our discovery reveals the topological nature of tellurium and further confirms the universality of DSI in topological materials. Moreover, introduction of Weyl physics into semiconductors to develop "Weyl semiconductors" provides an ideal platform for manipulating fundamental Weyl fermionic behaviors and for designing future topological devices.

Clinical significance of dynamical network indices of surface electromyography for reticular neuromuscular control assessment.

BACKGROUND: There is currently no objective and accurate clinical assessment of reticular neuromuscular control in healthy subjects or patients with upper motor neuron injury. As a result, clinical dysfunctions of neuromuscular control could just be semi-quantified, efficacies and mechanisms of various therapies for neuromuscular control improving are difficult to verify. METHODS: Fourteen healthy participants were required to maintain standing balance in the kinetostatics model of Gusu Constraint Standing Training (GCST). A backward and upward constraint force was applied to their trunk at 0°, 20° and 25°, respectively. The multiplex recurrence network (MRN) was applied to analyze the surface electromyography signals of 16 muscles of bilateral lower limbs during the tests. Different levels of MRN network indices were utilized to assess reticular neuromuscular control. RESULTS: Compared with the 0° test, the MRN indices related to muscle coordination of bilateral lower limbs, of unilateral lower limb and of inter limbs showed significant increase when participants stood in 20° and 25° tests (P < 0.05). The indices related to muscle contribution of gluteal, anterior thigh and calf muscles significantly increased when participants stood in 20° and 25° tests (P < 0.05). CONCLUSIONS: This study applied the dynamical network indices of MRN to analyze the changes of neuromuscular control of lower limbs of healthy participants in the kinetostatics model of GCST. Results showed that the overall coordination of lower limb muscles would be significantly enhanced during performing GCST, partly by the enhancement of neuromuscular control of single lower limb, and partly by the enhancement of joint control across lower limbs. In particular, the muscles in buttocks, anterior thighs and calves played a more important role in the overall coordination, and their involvement was significantly increased. The MRN could provide details of control at the bilateral lower limbs, unilateral lower limb, inter limbs, and single muscle levels, and has the potential to be a new tool for assessing the reticular neuromuscular control. Trial registration ChiCTR2100055090.

Kekulé Lattice in Graphdiyne: Coexistence of Phononic and Electronic Second-Order Topological Insulator.

Topological physics has been extensively studied in different kinds of bosonic and Fermionic systems, but the coexistence of topological phonons and electrons in one single material has seldom been reported. Recently, graphdiyne has been proposed as a two-dimensional (2D) electronic second-order topological insulator (SOTI). In this work, we found that graphdiyne is equivalent to Kekulé lattice, also realizing a 2D phononic SOTI in both out-of-plane and in-plane modes. Depending on edge terminations, the characterized topological corner states can be either inside or outside the bulk gap and are tunable by the local corner potential. Most remarkably, a unique selectivity of space and symmetry is revealed in the electron-phonon coupling between the localized phononic and electronic topological corner states. Our results not only demonstrate the phononic higher-order band topology in a real carbon material but also provide an opportunity to investigate the interplay between phononic and electronic higher-order topological states.

Layer-Number-Dependent Magnetism and Anomalous Hall Effect in van der Waals Ferromagnet Fe5GeTe2.

Realization of ferromagnetism in the two-dimensional (2D) van der Waals (vdW) crystals opens up a vital route to understand the magnetic ordering in the 2D limit and to design novel spintronics. Here, we report enriched layer-number-dependent magnetotransport properties in the vdW ferromagnet Fe5GeTe2. By studying the magnetoresistance and anomalous Hall effect (AHE) in nanoflakes with thicknesses down to monolayer, we demonstrate that while the bulk crystals exhibit soft ferromagnetism with an in-plane magnetic anisotropy, hard ferromagnetism develops upon thinning, and a perpendicular easy-axis anisotropy is realized in bilayer flakes, which is accompanied by a pronounced enhancement of AHE because of extrinsic mechanisms. For the monolayer flakes, the hard ferromagnetism is replaced by spin-glass-like behavior, in accordance with the localization effect in the 2D limit. Our results highlight the thickness-based tunability of the magnetotransport properties in the atomically thin vdW magnets that promises engineering of high-performance spintronic devices.

Flat-Band-Induced Anomalous Anisotropic Charge Transport and Orbital Magnetism in Kagome Metal CoSn.

For solids, the dispersionless flat band has long been recognized as an ideal platform for achieving intriguing quantum phases. However, experimental progress in revealing flat-band physics has so far been achieved mainly in artificially engineered systems represented as magic-angle twisted bilayer graphene. Here, we demonstrate the emergence of flat-band-dominated anomalous transport and magnetic behaviors in CoSn, a paramagnetic kagome-lattice compound. By combination of angle-resolved photoemission spectroscopy measurements and first-principles calculations, we reveal the existence of a kagome-lattice-derived flat band right around the Fermi level. Strikingly, the resistivity within the kagome lattice plane is more than one order of magnitude larger than the interplane one, in sharp contrast with conventional (quasi-) two-dimensional layered materials. Moreover, the magnetic susceptibility under the out-of-plane magnetic field is found to be much smaller as compared with the in-plane case, which is revealed to be arising from the introduction of a unique orbital diamagnetism. Systematic analyses reveal that these anomalous and giant anisotropies can be reasonably attributed to the unique properties of flat-band electrons, including large effective mass and self-localization of wave functions. Our results broaden the already fascinating flat-band physics, and demonstrate the feasibility of exploring them in natural solid-state materials in addition to artificial ones.

Excited quantum anomalous and spin Hall effect: dissociation of flat-bands-enabled excitonic insulator state.

Quantum anomalous Hall effect (QAHE) and quantum spin Hall effect (QSHE) are two interesting physical manifestations of 2D materials that have an intrinsic nontrivial band topology. In principle, they are ground-state equilibrium properties characterized by Fermi level lying in a topological gap, below which all the occupied bands are summed to a non-zero topological invariant. Here, we propose theoretical concepts and models of 'excited' QAHE (EQAHE) and EQSHE generated by dissociation of an excitonic insulator (EI) state with complete population inversion (CPI), a uniquemany-bodyground state enabled by two yin-yang flat bands (FBs) of opposite chirality hosted in a diatomic Kagome lattice. The two FBs have a trivial gap in between, i.e. the system is a trivial insulator in thesingle-particleground-state, but nontrivial gaps above and below, so that upon photoexcitation the quasi-Fermi levels of both electrons and holes will lie in a nontrivial gap achieved by the CPI-EI state, as demonstrated by exact diagonalization calculations. Then dissociation of singlet and triplet EI state will lead to EQAHE and EQSHE, respectively. Realizations of yin-yang FBs in real materials are also discussed.

The effects of ammonia stress exposure on protein degradation, immune response, degradation of nitrogen-containing compounds and energy metabolism of Chinese mitten crab.

BACKGROUND: The Chinese mitten crab is one of the most economically important crabs that are widely farmed in China. Ammonia, which is a main physiological challenge for crab culture, grows rapidly in the intensive culture system over time, but little information is available with Chinese mitten crab on the molecular mechanisms. METHODS AND RESULTS: Therefore, to understand the mechanism of response to ammonia stress in Eriocheir japonica sinensis, comparative transcriptome analysis was used to identify the key genes and pathways in hepatopancreas challenged with ammonia stress (325.07 mg/L NH4Cl). By sequencing the transcriptome hepatopancreas of E. j. sinensis treated with ammonia, 366,472 unigenes were obtained and annotated into several public libraries for later analyses. Subsequently, 1775 differentially expressed genes (DEGs) were identified according to comparative transcriptome analysis, of which 307 were up-regulated and 1468 were down-regulated. According to the DEGs of GO and KEGG enrichment analyses, we focused on four aspects of significant enrichment in this study: protein degradation, immune response, degradation of nitrogen-containing compounds and energy metabolism. The genes involved in protein degradation and energy metabolism process showed a significant decrease which was consisting of overall biological activity of E. j. sinensis decreased. In addition, five genes involved in high concentration of ammonia were discovered and validated by qRT-PCR. CONCLUSIONS: This study will help us understand the molecular mechanisms of E. j. sinensis under high ammonia exposure and provide valuable information to the future research of other crabs with ammonia exposure.

Comparative transcriptome analysis of the gills of Cardisoma armatum provides novel insights into the terrestrial adaptive related mechanism of air exposure stress.

Cardisoma armatum is a typical member of the Gecarcinidae which show significant behavioral, morphological, physiological, and/or biochemical adaptations permitting extended activities on the land. The special gills (branchiostegal lung) of C. armatum play an important role in maintaining osmotic pressure balance and obtaining oxygen to adapt to the terrestrial environment. However, adaptive molecular mechanisms responding to air exposure in C. armatum are still poorly understood. In this study, transcriptomic analysis and histological analysis were conducted on the gills to test adaptive capabilities over 8 h between the aerial exposure (AE) and the water immersion (WI) group. Differentially expressed genes (DEGs) related to terrestrial adaptation were categorized into four broad categories: ion transport, acid-base balance, energy metabolism and immune response. This is the first research to reveal the molecular mechanism of terrestrial adaptation in C. armatum, and will provide new insight into the molecular genetic basis of terrestrial adaptation in crabs.

Comparative transcriptome analysis of the gills of Procambarus clarkii provide novel insights into the response mechanism of ammonia stress tolerance.

Procambarus clarkii is an important model crustacean organism in many researches. Ammonia nitrogen is one of common contaminants in aquatic environment, influencing the health of aquatic organisms. The primary objective of this study was to investigate molecular mechanisms on ammonia stress in gills of P. clarkii to provide new insights into the strategies of aquatic animals in responding to high concentration of ammonia in the environment. Procambarus clarkii were randomly assigned into two groups (ammonia stress group, AG; control group, CG), and gill samples were dependently excised from AG and CG. Then response mechanisms on ammonia stress were investigated based on transcriptome data of P. clarkii. 9237 differentially expressed genes were identified in ammonia stress group. The genes of ion transport enzymes (NKA and SLC6A5S) were significantly up-regulated. Whereas the immune-related genes (e.g. MAP3K7, HSP70, HSP90A, CTSF, CTSL1, CHI and CTL4) and pathways were significantly up-regulated, which played an important role in reacting to ammonia stress. Procambarus clarkii may enhance immune defense to counteract ammonia toxicity by the up-regulation of immune-related genes and signaling pathways. The activities of ion transport enzymes are changed to mobilise signal transduction and ion channel regulation for adapting to ammonia environment. These previous key genes play an important role in resistance to ammonia stress to better prepare for survival in high concentration of ammonia.

The Entire Mitochondrial Genome of Macrophthalmus abbreviatus Reveals Insights into the Phylogeny and Gene Rearrangements of Brachyura.

Brachyuran crabs comprise the most species-rich clades among extant Decapoda and are divided into several major superfamilies. However, the phylogeny of Brachyuran remains controversial, comprehensive analysis of the overall phylogeny is still lacking. Complete mitochondrial genome (mitogenome) can indicate phylogenetic relationships, as well as useful information for gene rearrangement mechanisms and molecular evolution. In this study, we firstly sequenced and annotated the complete mitogenome of Macrophthalmus abbreviatus (Brachyura; Macrophthalmidae). The mitogenome length of M. abbreviatus is 16,322 bp, containing the entire set of 37 genes and a control region typically observed in Brachyuran mitogenomes. The genome composition of M. abbreviatus was highly A+T biased 76.3% showing positive AT-skew (0.033) and negative GC-skew (- 0.351). In M. abbreviatus mitogenome, most tRNA genes were folded into the clover-leaf secondary structure except trnH, trnS1 and trnC, which was similar to the other species in Macrophthalmidae. Phylogenetic analysis showed that all families form a monophyletic, and Varunidae and Macrophthalmidae clustered into a monophyletic clade as sister groups. Comparative analyses of rearrangement among Brachyura revealed that Varunidae (Grapsoidea) and Macrophthalmidae (Ocypodoidea) had the same gene order, which reinforced the result of phylogeny. The combined results of two aspects revealed that the polyphyly of Ocypodoidea and Grapsoidea were well supported. In general, the results obtained in this research will contribute to further studies on molecular based for the classification and gene rearrangements of Macrophthalmidae or even Brachyura.

A Traditional Chinese Medicine Traceability System Based on Lightweight Blockchain.

BACKGROUND: Recently, the problem of traditional Chinese medicine (TCM) safety has attracted attention worldwide. To prevent the spread of counterfeit drugs, it is necessary to establish a drug traceability system. A traditional drug traceability system can record the whole circulation process of drugs, from planting, production, processing, and warehousing to use by hospitals and patients. Once counterfeit drugs are found, they can be traced back to the source. However, traditional drug traceability systems have some drawbacks, such as failure to prevent tampering and facilitation of sensitive disclosure. Blockchain (including Bitcoin and Ethernet Square) is an effective technology to address the problems of traditional drug traceability systems. However, some risks impact the reliability of blockchain, such as information explosion, sensitive information leakage, and poor scalability. OBJECTIVE: To avoid the risks associated with the application of blockchain, we propose a lightweight block chain framework. METHODS: In this framework, both horizontal and vertical segmentations are performed when designing the blocks, and effective strategies are provided for both segmentations. For horizontal segmentation operations, the header and body of the blockchain are separated and stored in the blockchain, and the body is stored in the InterPlanetary File System. For vertical segmentation operations, the blockchain is cut off according to time or size. For the addition of new blocks, miners only need to copy the latest part of the blockchain and append the tail and vertical segmentation of the block through the consensus mechanism. RESULTS: Our framework could greatly reduce the size of the blockchain and improve the verification efficiency. CONCLUSIONS: Experimental results have shown that the efficiency improves compared with ethernet when a new block is added to the blockchain and a search is conducted.

Toxic effects of metal copper stress on immunity, metabolism and pathologic changes in Chinese mitten crab (Eriocheir japonica sinensis).

Copper (Cu2+), which represents a major physiological challenge for crab culture, is ubiquitous in the aquatic culture environment, and gills are the first organs that come into direct contact with the environment. However, the molecular basis of the response of crabs to Cu2+ stress remains unclear. Here, we conducted a transcriptome and differential expression analysis on the gills from Chinese mitten crab unexposed and exposed to Cu2+ for 24 h. The comparative transcriptome analysis identified 2486 differentially expressed genes (DEGs). GO functional analysis and KEGG pathway analysis revealed some DEGs, which were mostly related to immunity, metabolism, osmotic regulation, Cu2+ homeostasis regulation, antioxidant activity, and detoxification process. Some pathways related to humoral and cellular immunity, such as phagosome, peroxisome, lysosome, mTOR signaling pathway, PI3K-Akt signaling pathway, Toll-like receptor signaling pathway, and T cell receptor signaling pathway were enhanced under Cu2+ stress. In addition, Cu2+ stress altered the expression patterns of key phagocytosis and apoptosis genes (lectin, cathepsin L, Rab7, and HSP70), confirming that Cu2+ can induce oxidative stress and eventually even apoptosis. Histological analysis revealed that the copper can induce damage at the cellular level. This comparative transcriptome analysis provides valuable molecular information to aid future study of the immune mechanism of Chinese mitten crab in response to Cu2+ stress and provides a foundation for further understanding of the effects of metal toxicity.

Characterization of the complete mitochondrial genome of Uca lacteus and comparison with other Brachyuran crabs.

Brachyuran crabs comprise the most species-rich clade among the crustacean order Decapoda and are divided into several major superfamilies. However, the monophyly of the superfamilies Ocypodoidea and Grapsoidea in their current compositions within the Brachyura remains inconclusive. In this study, the complete mitochondrial genome (mitogenome) of Uca lacteus (Ocypodoidea, Ocypodidae) was sequenced, annotated, and compared with those of other Brachyuran crabs. The circular mitogenome of U. lacteus is 15,661 base pairs long and contains the entire set of 37 genes and an A + T-rich region typically observed in decapod mitogenomes. Secondary structures of several tRNAs are partly missing (trnS1), and the number of bases is significantly decreased (trnD and trnF), as discovered in many other metazoans. We compared the gene order of U. lacteus with other species of Ocypodidae and found that they are consistent. The gene rearrangement of Ocypodidae is also identical to that of the ancestor of Brachyura. However, the order of the trnH gene varies from the rearrangement of ancestral Decapoda. Accordingly, we hypothesized that this rearrangement of trnH underwent a translocation during the evolution from Decapoda to Brachyura. The phylogenetic relationship of the 81 Brachyura species and one outgroup was recovered based on 13 protein-coding genes. This analysis confirmed that U. lacteus belongs to the family Ocypodidae and established a paraphyletic relationship between Ocypodoidea and Grapsoidea.

Comparative mitochondrial genomic analysis of Macrophthalmus pacificus and insights into the phylogeny of the Ocypodoidea & Grapsoidea.

Grapsoidea and Ocypodoidea, two of the most abundant and economically important groups in Brachyura, are of great commercial value to fisheries and aquaculture. However, the taxonomy of Ocypodoidea and Grapsoidea has long been highly disputed. Previous studies have investigated this problem through phylogenetic analysis based on limited taxonomic sampling, with different reports proposing either monophyly or paraphyly, but no definitive conclusion has been reached. In this study, the complete mitogenome of Macrophthalmus pacificus (Ocypodoidea, Macrophthalmidae) is reported on and the relationship between Ocypodoidea and Grapsoidea is further investigated. Sequencing the M. pacificus mitogenome, which is a closed circular molecule containing a typical 37 genes, preliminarily determined the ancestral gene order of Macrophthalmidae, which is consistent with previous studies. Comparative analyses of gene order among Ocypodoidea and Grapsoidea revealed that Varunidae (Grapsoidea) and Macrophthalmidae (Ocypodoidea) have the same rearrangement, which confirms previous research. Larger data analysis revealed that these two families (Varunidae and Macrophthalmidae) cluster into a monophyletic clade as sister groups. Rearrangement and phylogeny lines of evidence is concluded that Varunidae and Macrophthalmidae may be of common origin. Furthermore, the remaining Ocypodoidea and Grapsoidea families mix paraphyletically in the phylogenetic tree. Therefore, both gene rearrangement and phylogenetic analysis support the paraphyly of Ocypodoidea and Grapsoidea, which reinforces this view. These findings provide important information regarding Brachyura's phylogenetic relationships, which demonstrates the advantage of mitogenome sequence data in phylogenetic studies.