Photoinduced Floquet higher-order Weyl semimetal in C_(6) symmetric Dirac semimetals

Topological Dirac semimetals are a parent state from which other exotic topological phases of matter, such as Weyl semimetals and topological insulators, can emerge. In this study, we investigate a Dirac semimetal possessing sixfold rotational symmetry and hosting higher-order topological hinge Fermi arc states, which is irradiated by circularly polarized light. Our findings reveal that circularly polarized light splits each Dirac node into a pair of Weyl nodes due to the breaking of time-reversal symmetry, resulting in the realization of the Weyl semimetal phase. This Weyl semimetal phase exhibits rich boundary states, including two-dimensional surface Fermi arc states and hinge Fermi arc states confined to six hinges.Furthermore, by adjusting the incident direction of the circularly polarized light, we can control the degree of tilt of the resulting Weyl cones, enabling the realization of different types of Weyl semimetals.

Majorana Corner Modes and Flat-Band Majorana Edge Modes in Superconductor/Topological-Insulator/Superconductor Junctions

Recently,superconductors with higher-order topology have stimulated extensive attention and research interest.Higher-order topological superconductors exhibit unconventional bulk-boundary correspondence,thus allow exotic lower-dimensional boundary modes,such as Majorana corner and hinge modes.However,higher-order topological superconductivity has yet to be found in naturally occurring materials.We investigate higher-order topology in a two-dimensional Josephson junction comprised of two s-wave superconductors separated by a topological insulator thin film.We find that zero-energy Majorana corner modes,a boundary fingerprint of higherorder topological superconductivity,can be achieved by applying magnetic field.When an in-plane Zeeman field is applied to the system,two corner modes appear in the superconducting junction.Furthermore,we also discover a two-dimensional nodal superconducting phase which supports flat-band Majorana edge modes connecting the bulk nodes.Importantly,we demonstrate that zero-energy Majorana corner modes are stable when increasing the thickness of topological insulator thin film.

Positional and expressive alteration of prohibitin during the induced differentiation of human hepatocarcinoma SMMC-7721 cells

AIM: To explore the existence and distribution of prohibitin (PHB) in nuclear matrix and its co-localization with products of some related genes during the differentiation of human hepatocarcinoma SMMC-7721 cells. METHODS: The nuclear matrix of the SMMC-7721 cells cultured with or without 5 × 10-3 mmol/L hexamethylene bisacetamide (HMBA) was selectively extracted. Western blot was used to analyze the expression of PHB in nuclear matrix; immunofl uorescence microscope observation was used to analyze the distribution of PHB in cell. LCSM was used to observe the co-localization of PHB with products of oncogenes and tumor suppressor genes. RESULTS: Western blot analysis showed that PHB existed in the composition of nuclear matrix proteins and was down-regulated by HMBA treatment. Immunofluorescence observation revealed that PHB existed in the nuclear matrix, and its distribution regions and expression levels were altered after HMBA treatment. Laser scanning confocal microscopy revealed the co-localization between PHB and theproducts of oncogenes or tumor repression genes including c-fos, c-myc, p53 and Rb and its alteration of distributive area in the cells treated by HMBA. CONCLUSION: These data confirm that PHB is a nuclear matrix protein, which is located in the nuclear matrix, and the distribution and expression of PHB and its relation with associated genes may play signifi cant roles during the differentiation of SMMC-7721 cells.

Alreration of nuclear matrix-intermediate filament system and differential expression of nuclear matrix proteins during human hepatocarcinoma cell differentiation

AIM:To investigate the association between the configurational and compositional changes of nuclear matrix and the differentiation of carcinoma cells. METHODS: Cells cultured with or without 5 x 10"3 mmol/L of hexamethylene bisacetamide (HMBA) on Nickel grids were treated by selective extraction and prepared for whole mount observation under electron microscopy. The samples were examined under transmission electron microscope. Nuclear matrix proteins were selectively extracted and subjected to subcellular proteomics study. The protein expression patterns were analyzed by PDQuest software. Spots of differentially expressed nuclear matrix proteins were excised and subjected to in situ digestion with trypsin. The peptides were analyzed by matrix-assisted laser-desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Data were submitted for database searching using Mascot tool (www.matrixscience.com). RESULTS: The nuclear matrix (NM) and intermediate filament (IF) in SMMC-7721 hepatocarcinoma cells were found relatively sparse and arranged irregularly. The nuclear lamina was non-uniform,and two kinds of filaments were not tightly connected. After induction for differentiation by HMBA,the NM-IF filaments were concentrated and distributed uniformly. The heterogeneous population of filaments,including highly branched utrathin filaments could also be seen in the regular meshwork. The connection between the two kinds of filaments and the relatively thin,condensed and sharply demarcated lamina composed of intermediate-sized filaments was relatively fastened. Meanwhile,21 NM proteins changed remarkably during SMMC-7721 cell differentiation. Four proteins,i.e. mutant Pyst1,hypothetical protein,nucleophosminl,and LBP were downregulated,whereas four other proteins,eIF6,p44 subunit,(3-tubulin,and SIN3B were upregulated with the last one,SR2/ASF found only in the differentiated SMMC-7721 cells. CONCLUSION: The induced differentiation of SMMC-7721 cells by HMBA is accompanied by the configurational changes of nuclear matrix-intermediate filament (NM-IF) system and the compositional changes of nuclear matrix protein expression. These changes may be important morphological or functional indications of the cancer cell reversion.

Colitis and colorectal tumors should be further explored and differentiated

The original article by Yuichi et al explored whether the Japan Narrow-Band Imaging Expert Team classification and the pit pattern classification are suitable for diagnosing neoplastic lesions in patients with ulcerative colitis.In this letter,we offer some other perspectives.Risk factors for colorectal tumors include type 2 diabetes.Among genetic factors,the deletion or mutation of some genes,such as the p53 gene,can lead to colorectal tumors.There are significant gender differences in the occurrence and development of colorectal tumors.Some nongenetic factors,such as smoking,are also associated with the development of colorectal tumors.These all suggest that colorectal tumors are not only caused by ulcerative colitis,and we suggest further exploration and differentiation between colitis and colorectal tumors.

Fuzhuan brick tea affects obesity process by modulating gut microbiota

The effect of Fuzhuan brick tea(FBT)on metabolism in obese mice is mediated by regulation of N-methyltransferase by aryl hydrocarbon receptor.The expression of the phosphatidylethanolamine N-methyltransferase gene is regulated by many transcription factors,and those specific to this effect need further investigation.Experimental animal studies have been designed to observe the effects of a single drug or the sequential effects of drugs.A washout period should be included if different drugs(e.g.,antibiotics and FBT)are given to avoid or reduce additive effects or synergy.Currently,most experimental studies performed in mice used only male animals.However,experience has revealed that the results of using only male mice are very likely to have sex differences.

Glucose substrate in the hydrogen breath test for gut microbiota determination:A recommended noninvasive test

Intestinal dysbiosis and small intestinal bacterial overgrowth(SIBO)are common in patients with liver cirrhosis.Existing studies have not explored the association between gut dysbiosis and SIBO.We propose some suggestions for the authors’experimental methods and concepts,and we hope these suggestions can be adopted.The hydrogen breath test is worthy of recommendation due to its high accuracy and convenient operation.We suggest changing the substrate of the hydrogen breath test from lactulose to glucose to improve the accuracy of each parameter.SIBO is a small subset of gut dysbiosis,and we propose clarifying the concept of both.SIBO may be caused by liver cirrhosis or one of the pathogeneses of gastrointestinal diseases.Therefore,interference from other gastrointestinal diseases should be excluded from this study.

Chiral edge state coupling theory of transport in quantum anomalous Hall insulators

The quantum anomalous Hall effect is characterized by a quantized Hall resistance with a vanishing longitudinal resistance.Many experiments reported the quantization of the Hall resistance,which is always accompanied by a non-vanishing longitudinal resistance that is several k?.Meanwhile,the non-vanishing longitudinal resistance exhibits a universal exponential decay with the increase in magnetic field.We propose that the coupling of chiral edge states,which has not been properly evaluated in the previous theories,can give rise to the non-vanishing longitudinal resistance.The coupling between the chiral edges states along the opposite boundaries can be assisted by magnetic domains or defects inside the sample bulk,which has been already identified in recent experiments.Our theory provides a potential mechanism to understand the experimental result in both magnetic topological insulator and moirésuperlattice systems.

Doubled Moiré fat bands in double-twisted few-layer graphite

We study the electronic structure of double-twisted few-layer graphite(DTFLG),which consists of three few-layer graphites(FLGs),i.e.,an ABA-stacked graphene multilayer,stacked with two twist angles.We consider two categories of DTFLG,the alternately and chirally twisted cases,according to the rotation direction of the two twist angles.We show that,once the middle FLG of DTFLG is not thinner than the trilayer,both types of DTFLG can remarkably host two pairs of degenerate Moire flat bands(MFBs) at EF,twice that of the magic angle twisted bilayer graphene(TBG).The doubled MFBs of DTFLG lead to a doubled density of states(DOS) at the Fermi level EF,which implies much stronger correlation effects than TBG.The degeneracy of MFBs can be lifted by a perpendicular electric field,and the isolated MFBs have a nonzero valley Chern number.We also reveal the peculiar wave function patterns of the MFB s in DTFLG.Our results establish a new family of Moire systems that have a much higher DOS at EFand thus possibly much stronger correlation effects.

Association between tobacco exposure and bladder cancer recurrence:A systematic review and meta-analysis

BACKGROUND However,the connection between smoking and the prognosis of patients with bladder cancer remains unclear.AIM To determine whether smoking is linked to the recurrence and progression of bladder cancer.METHODS As of July 20,2022,relevant English-language research was identified by searching PubMed,the Web of Science,and the Cochrane Library.We pooled the available data from the included studies using a random effects model.Subgroup analysis and sensitivity analysis were also conducted.RESULTS A total of 12 studies were included in this meta-analysis.The combined analysis revealed that tobacco exposure was associated with a significantly greater recurrence rate than nonsmoking status[odd ratios(OR)=1.76,95%CI:1.84-2.93],and the progression of bladder cancer was significantly greater in smokers than in nonsmokers(OR=1.21,95%CI:1.02-1.44).Stratified analysis further revealed that current smokers were more likely to experience relapse than never-smokers were(OR=1.85,95%CI:1.11-3.07).Former smokers also had a greater risk of relapse than did never-smokers(OR=1.73,95%CI:1.09-2.73).Subgroup analysis indicated that non-Caucasians may be more susceptible to bladder cancer recurrence than Caucasians are(OR=2.13,95%CI:1.74-2.61).CONCLUSION This meta-analysis revealed that tobacco exposure may be a significant risk factor for both the recurrence and progression of bladder cancer.

Evolution of Berry curvature and reentrant quantum anomalous Hall effect in an intrinsic magnetic topological insulator

Recently, the magnetic topological insulator(TI) MnBi2Te4 emerged as a competitive platform to realize quantum anomalous Hall(QAH) states. We report a Berry curvature splitting mechanism to realize the QAH effect in the disordered magnetic TI multilayers when switching from an antiferromagnetic order to a ferromagnetic order. We reveal that the splitting of spin-resolved Berry curvature, originating from the separation of the critical points during the magnetic switching, can give rise to a QAH insulator. We present a global phase diagram, and also provide a phenomenological picture to elucidate the Berry curvature splitting mechanism by the evolution of topological charges. At last, we predict that the Berry curvature splitting mechanism will lead to a reentrant QAH effect, which can be detected by tuning the gate voltage. Our theory will be instructive for the studies of the QAH effect in MnBi2Te4 in future experiments.

Emergent Z2 topological invariant and robust helical edge states in two-dimensional topological metals

In this work,we study the effects of disorder on topological metals that support a pair of helical edge modes deeply embedded inside the gapless bulk states.Strikingly,we predict that a quantum spin Hall(QSH)phase can be obtained from such topological metals without opening a global band gap.To be specific,disorder can lead to a pair of robust helical edge states which is protected by an emergent Z2 topological invariant,giving rise to a quantized conductance plateau in transport measurements.These results are instructive for solving puzzles in various transport experiments on QSH materials that are intrinsically metallic.This work also will inspire experimental realization of the QSH effect in disordered topological metals.

Higher-order valley vortices enabled by synchronized rotation in a photonic crystal

Synchronized rotation of unit cells in a periodic structure provides a novel design perspective for manipulation of band topology.We then design a two-dimensional version of higher-order topological insulator(HOTI)by such rotation in a triangular photonic lattice with C_(3) symmetry.This HOTI supports the hallmark zero-dimensional corner states and,simultaneously,the one-dimensional edge states.We also find that our photonic corner states carry chiral orbital angular momenta locked by valleys,whose wave functions are featured by the phase vortex(singularity)positioned at the maximal Wyckoff points.Moreover,when excited by a fired source with various frequencies,the valley topological states of both one-dimensional edges and zero-dimensional corners emerge simultaneously.Extendable to higher or synthetic dimensions,our paper provides access to a chiral vortex platform for HOTI realizations in the terahertz photonic system.