Focusing Micromechanical Polaritons in Topologically Nontrivial Hyperbolic Metasurfaces.

Vertically stacked multiple atomically thin layers have recently widened the landscape of rich optical structures thanks to these quantum metamaterials or van der Waals (vdW) materials, featuring hyperbolic polaritons with unprecedented avenues for light. Despite their far-reaching implications, most of their properties rest entirely on a trivial band topological origin. Here, a 2D approach is adopted toward a micromechanical vdW analogue that, as a result of engineered chiral and mirror symmetries, provides topologically resilient hyperbolic radiation of mechanical vibrations in the ultrasonic regime. By applying laser vibrometry of the micrometer-sized metasurface, we are able to exhibit the exotic fingerprints of robust hyperbolic radiation spanning several frequencies, which beyond their physical relevance, may enable ultrasonic technologies.

Network pharmacology to explore the mechanism of scutellarin in the treatment of brain ischaemia and experimental verification of JAK2/STAT3 signalling pathway.

Scutellarin is used to treat brain ischaemia. However, its underlying mechanism of action remains unclear. This study aimed to elucidate the potential mechanism of action of scutellarin in brain ischaemia through network pharmacology and experimental verification. The JAK2/STAT3 signalling pathway was identified and experimentally verified. Expression of JAK2/STAT3 signalling related proteins in TNC-1 astrocytes with BV-2 microglia-conditioned medium (CM), CM + lipopolysaccharide (LPS) (CM + L), and CM pretreated with scutellarin + LPS (CM + SL) was analysed by Western Blot and immunofluorescence staining. Expression levels of JAK2, p-JAK2, STAT3, and p-STAT3 were evaluated in astrocytes pre-treated with AG490. Middle cerebral artery occlusion (MCAO) in rats was performed in different experimental groups to detect expression of the above biomarkers. Network pharmacology suggested that the JAK2/STAT3 signalling pathway is one of the mechanisms by which scutellarin mitigates cerebral ischaemic damage. In TNC-1 astrocytes, p-JAK2 and p-STAT3 expression were significantly up-regulated in the CM + L group. Scutellarin promoted the up-regulation of various markers and AG490 neutralised the effect of scutellarin. In vivo, up-regulation of p-JAK2 and p-STAT3 after ischaemia is known. These results are consistent with previous reports. Scutellarin further enhanced this upregulation at 1, 3, and 7 d after MCAO. Scutellarin exerts its therapeutic effects on cerebral ischaemia by activating the astrocyte JAK2/STAT3 signalling, which provides a firm experimental basis for its clinical application.

Scutellarin Acts via MAPKs Pathway to Promote M2 Polarization of Microglial Cells.

Scutellarin, an herbal agent, is known to possess anti-oxidant and anti-inflammatory properties. In activated microglia, it has been reported that this is achieved through acting on the MAPKs, a key pathway that regulates microglia activation. This study sought to determine if scutellarin would affect the commonly described microglia phenotypes, namely, M1 and M2, thought to contribute to pro- and anti-inflammatory roles, respectively. This is in consideration of its potential effect on the polarization of microglia phenotypes that are featured prominently in cerebral ischemia. For this purpose, we have used an experimentally induced cerebral ischemia rat model and LPS-stimulated BV-2 cell model. Thus, by Western blot and immunofluorescence, we show here a noticeable increase in expression of M2 microglia markers, namely, CD206, Arg1, YM1/2, IL-4 and IL-10 in activated microglia both in vivo and in vitro. Besides, we have confirmed that Scutellarin upregulated expression of Arg1, IL-10 and IL-4 in medium supernatants of BV-2 microglia. Remarkably, scutellarin treatment markedly augmented the increased expression of the respective markers in activated microglia. It is therefore suggested scutellarin can exert the polarization of activated microglia from M1 to M2 phenotype. Because M1 microglia are commonly known to be proinflammatory, while M2 microglia are anti-inflammatory and neuroprotective effect, it stands to reason therefore that with the increase of M2 microglia which became predominant by scutellarin, the local inflammatory response is ameliorated. More importantly, we have found that scutellarin promotes the M2 polarization through inhibiting the JNK and p38 signaling pathways, and concomitantly augmenting the ERK1/2 signaling pathway. This lends its strong support from observations in LPS activated BV-2 microglia treated with p38 and JNK inhibitors in which expression of M2 markers was increased; on the other hand, in cells subjected to ERK1/2 inhibitor treatment, the expression was suppressed. In light of the above, MAPKs pathway is deemed to be a potential therapeutic target of scutellarin in mitigating microglia mediated neuroinflammation in activated microglia.

Special issue "The advance of solid tumor research in China": Participants with a family history of cancer have a higher participation rate in low-dose computed tomography for lung cancer screening.

We aimed to determine participation in low-dose computed tomography (LDCT) of individuals with a family history of common cancers in a population-based screening program to provide timely evidence in high-risk populations in China. The analysis was conducted using data from the Cancer Screening Program in Urban China (CanSPUC), which recruited 282 377 participants aged 40 to 74 years from eight cities in the Henan province. Using the CanSPUC risk score system, 55 428 participants were evaluated to have high risk for lung cancer and were recommended for LDCT. We calculated the overall and group-specific participation rates using family history of common cancers and compared differences in participation rates between different groups. Odds ratios (ORs) and 95% confidence intervals were derived by multivariable logistic regression. Of the 55 428 participants, 22 260 underwent LDCT (participation rate, 40.16%). Family history of lung, esophageal, stomach, liver and colorectal cancer was associated with increased participation in LDCT screening. The odds of participants with a family history of one, two, three and four or more cancer cases undergoing LDCT screening were 1.9, 2.7, 2.8 and 3.5 times, respectively, than those without a family history of cancer. Compared to those without a history of cancer, participation in LDCT gradually increased as the number of cancer cases in the family increased (P < .001). Our findings suggest that there is room for improvement in lung cancer screening given the relatively low participation rate. Lung cancer screening in populations with a family history of cancer may improve efficiency and cost-effectiveness; however, this requires further verification.

A cluster randomized controlled trial to evaluate the efficacy of esophageal and gastric cancer screening in mortality reduction in a non-high-incidence area: methodology and initial results.

Background: A cluster randomized controlled trial of endoscopy-based screening for esophageal cancer (EC) and gastric cancer (GC) was conducted to evaluate the efficacy and feasibility of this strategy in a non-high-incidence rural area of China. The trial design and baseline findings are presented here. Methods: A total of 33 eligible villages in Luoshan County in Henan Province were assigned randomly to the intervention or control group in a 1:1 ratio by a computer-generated randomization list. Local residents aged 40 to 69 years were enrolled from the villages. Participants in the intervention group were risk-stratified with a questionnaire, and high-risk individuals were subsequently screened by endoscopy. The primary outcomes were EC and GC mortality. The secondary outcomes comprised the detection rate, stage distribution, and the treatment rate. In this study, baseline characteristics were assessed by a questionnaire. Multivariate logistic regression analysis was performed to explore factors associated with endoscopy compliance. Results: Trial recruitment was completed in 2017, and ultimately, there were 12,475 and 11,442 participants allocated to the intervention (17 clusters) and the control group (16 clusters), respectively. We included 23,653 participants in the analysis, with 12,402 in the intervention group and 11,251 in the control group. A total of 6,286 (50.7%) participants in the intervention group were estimated as high-risk individuals, and 2,719 (43.3%) underwent endoscopy. Multivariate logistic regression analysis demonstrated that some factors including age, gender, education, personality and mental health, and upper gastrointestinal diseases or symptoms might affect endoscopy compliance. The detection rates for positive cases of EC and GC were 0.22% and 0.55%, respectively. The rates for esophageal and gastric precancerous lesions were 0.70% and 2.35%, respectively. The early detection rates for EC and GC were 50.0% and 33.3%, respectively. Additionally, the overall treatment rate for positive cases was 90.0%. Conclusions: The diagnostic yield of endoscopy-based screening for EC and GC was relatively low in a non-high-incidence rural area. The study may offer clues for the improvement of endoscopy compliance and the optimization of screening strategies for upper gastrointestinal cancer in non-high-incidence areas. Trial Registration: Chinese Clinical Trial Registry ChiCTR-EOR-16008577.

Development and Validation of a Noninvasive Risk Score Model for Liver Cirrhosis in At-Risk Alcohol Drinkers Without HBV/HCV Infection.

At-risk alcohol consumption is the established most important risk factor for cirrhosis in people without HBV/HCV infection. We aimed to develop and validate a simple and non-invasive tool for triaging cirrhosis risk in at-risk alcohol drinkers without HBV/HCV infection. A large-sample size, cross-sectional study within the framework of a population-based Cancer Screening Program in Urban China (CanSPUC) was conducted. Data on the liver cancer screening in Henan province, China were used. At-risk alcohol drinkers were those who currently drink one or more alcohol units per week for at least six months. A total of 6,581 eligible participants enrolled from October 1, 2013 to December 31, 2016 were included into the derivation dataset, and 2,096 eligible participants enrolled from January 1, 2017 to October 31, 2018 were included into the external validation dataset, respectively. Using the derivation dataset, a 20-point scale risk score model was developed, based on sex, education background, dietary intake of vegetables, dietary intake of roughage, smoking index, length of secondhand smoke exposure, history of fatty liver, history of diabetes, and first-degree family history of liver cancer. The model showed excellent discrimination (AUC = 0.787; 95% CI, 0.7603-0.812) and calibration (Hosmer-Lemeshow test: P = 0.123) in the derivation dataset and an optimal cut-off value of 12 yield sensitivity of 61.3%, specificity of 82.7%. The model also had achieved similar performance in the external validation dataset. In conclusion, this model can be a practical tool to identify and triage population at high risk of cirrhosis in at-risk alcohol drinkers without HBV/HCV infection. PREVENTION RELEVANCE: The risk model we developed will not only be used as a practical tool to triage high risk groups for liver cirrhosis, but also have implications for public health measures, such as guidelines for the prevention of liver cancer, in at-risk alcohol drinkers without HBV/HCV infection.

Time-trend of the incidence and mortality of esophageal cancer from 2010 to 2018 and its statistics in 2018 in Henan, China.

Background: It is great of significance to figure the time-trend of esophageal cancer (EC) and its current status for effective prevention and control, especially in EC high risk areas. As one of world-renowned high-risk areas, the epidemiology of EC in Henan has not been recently updated. Therefore, we aimed to depict the status quo of EC and analyze its time-trend in Henan. Methods: The EC data were extracted from the Henan Provincial Cancer registry database derived from the population based cancer registry system, which covered 30.51% of the whole population in Henan and were qualified according to national and international guidelines. The incidence and mortality of EC were estimated by area (rural/urban), gender, and age groups. The age-standardized rates (ASRs) were calculated according to the Segi's population. Joinpoint regression was used to calculate annual percentage change (APC) and average annual percentage change (AAPC) to evaluate the time-trend of EC. Results: As estimated, there were 29,913 new EC cases in Henan, 2018. The crude incidence and the age-standardized incidence rate by world standard population (ASIRW) was 27.43/105 and 19.96/105, respectively. The incidence in males and rural was 1.83 and 1.51 times higher than that in females and urban areas, respectively. Meanwhile, it was estimated that 22,688 deaths occurred in 2018. The crude mortality and the age-standardized mortality rate by world standard population (ASMRW) were 20.80/105 and 14.47/105, respectively. Similarly, males and rural areas had higher mortality compared with females and urban areas. The age-specific incidence and mortality of EC showed significant increasing after 60-64 years group. In general, the time-trend of incidence (APC: -8.9, P<0.001) and mortality (APC: -7.6, P<0.001) of EC showed a significant decreasing trend since 2014, and downward trend were also observed in rural areas for incidence (APC: -5.2, P<0.001) and mortality (APC: -3.9, P<0.001) from 2010 to 2018. Conclusions: The EC incidence and mortality in Henan has exhibited a significant declining trend in past years. Nonetheless, the disease burden remains high, especially in males and rural areas. Therefore, the ongoing prevention and control strategies of EC should be maintained alongside the establishment of more effective strategies.

Corrigendum: Construction and Validation of a Lung Cancer Risk Prediction Model for Non-Smokers in China.

[This corrects the article DOI: 10.3389/fonc.2021.766939.].

Risk of Liver Cirrhosis in HBV/HCV-Infected Individuals with First-Degree Relatives Who Have Liver Cancer: Development and Validation of a Simple Model.

Identification of high-risk population among hepatitis B virus (HBV)/hepatitis C virus (HCV)-infected individuals with first-degree relatives (FDR) who have liver cancer is important to implement precise intervention. A cross-sectional study was conducted under the framework of a population-based Cancer Screening Program in Urban China (CanSPUC), aimed to develop and validate a simple noninvasive model that could assess and stratify cirrhosis risk, in HBV/HCV-infected individuals with FDRs who have liver cancer. People who participated in liver cancer screening in Henan province were enrolled. Using the data set consisting of participants admitted from October 1, 2013, to December 31, 2016, a 24-point scale risk score model was developed through logistic regression, based on educational background, dietary habit, smoking index, cooking oil fume exposure, history of severe trauma, HBV/HCV infection status, history of diabetes, history of hyperlipidemia, and parent history of liver cancer. The model showed excellent discrimination with area under the receiver operator characteristic curve (AUROC) of 0.875 [95% confidence interval (CI), 0.853-0.896] and fair calibration with a Hosmer-Lemeshow test P = 0.106. The prevalence rates in the medium- and high-risk groups were 2.87 (95% CI, 1.94-4.25) and 47.57 (95% CI, 31.59-71.63) times of low-risk group, respectively. After internal validation, bias-corrected AUROC was 0.874 (95% CI, 0.873-0.875). In the external validation data set consisting of participants admitted from January 1, 2017, to October 31, 2018, the model had achieved similar discrimination, calibration, and risk stratification ability. In conclusion, the risk score model we developed can be a practical tool for the screening and prevention of liver cirrhosis among HBV/HCV-infected individuals with FDRs who have liver cancer. PREVENTION RELEVANCE: We created a simple and noninvasive cirrhosis risk model for individuals infected by HBV/HCV who have FDRs with liver cancer. This model is useful not only for the prognosis of HBV/HCV infection, but also for the prevention of hepatocellular carcinoma.

A risk prediction model for selecting high-risk population for computed tomography lung cancer screening in China.

OBJECTIVE: Two large randomized controlled trials (RCTs) have demonstrated that low dose computed tomography (LDCT) screening reduces lung cancer mortality. Risk-prediction models have been proved to select individuals for lung cancer screening effectively. With the focus on established risk factors for lung cancer routinely available in general cancer screening settings, we aimed to develop and internally validated a risk prediction model for lung cancer. MATERIALS AND METHODS: Using data from the Cancer Screening Program in Urban China (CanSPUC) in Henan province, China between 2013 and 2019, we conducted a prospective cohort study consisting of 282,254 participants including 126,445 males and 155,809 females. Detailed questionnaire, physical assessment and follow-up were completed for all participants. Using Cox proportional risk regression analysis, we developed the Henan Lung Cancer Risk Models based on simplified questionnaire. Model discrimination was evaluated by concordance statistics (C-statistics), and model calibration was evaluated by the bootstrap sampling, respectively. RESULTS: By 2020, a total of 589 lung cancer cases occurred in the follow-up yielding an incident density of 64.91/100,000 person-years (pyrs). Age, gender, smoking, history of tuberculosis and history of emphysema were included into the model. The C-index of the model for 1-year lung cancer risk was 0.766 and 0.741 in the training set and validation set, respectively. In stratified analysis, the model showed better predictive power in males, younger participants, and former or current smoking participants. The model calibrated well across the deciles of predicted risk in both the overall population and all subgroups. CONCLUSIONS: We developed and internally validated a simple risk prediction model for lung cancer, which may be useful to identify high-risk individuals for more intensive screening for cancer prevention.

Dirac Hierarchy in Acoustic Topological Insulators.

Dirac cones are essential features of the electronic band structure of materials like graphene and topological insulators (TIs). Lately, this avenue has found a growing interest in classical wave physics by using engineered artificial lattices. Here, we demonstrate an acoustic 3D honeycomb lattice that features a Dirac hierarchy comprising an eightfold bulk Dirac cone, a 2D fourfold surface state Dirac cone, and a 1D twofold hinge state Dirac cone. The lifting of the Dirac degeneracy in each hierarchy authorizes the 3D lattice to appear as a first-order TI with 2D topological surface states, a second-order TI exhibiting 1D hinge states, and a third-order TI of 0D midgap corner states. Analytically we discuss the topological origin of the surface, hinge, and corner states, which are all characterized by out-of-plane and in-plane winding numbers. Our study offers new routes to control sound and vibration for acoustic steering and guiding, on-chip ultrasonic energy concentration, and filtering to name a few.

Construction and Validation of a Lung Cancer Risk Prediction Model for Non-Smokers in China.

BACKGROUND: About 15% of lung cancers in men and 53% in women are not attributable to smoking worldwide. The aim was to develop and validate a simple and non-invasive model which could assess and stratify lung cancer risk in non-smokers in China. METHODS: A large-sample size, population-based study was conducted under the framework of the Cancer Screening Program in Urban China (CanSPUC). Data on the lung cancer screening in Henan province, China, from October 2013 to October 2019 were used and randomly divided into the training and validation sets. Related risk factors were identified through multivariable Cox regression analysis, followed by establishment of risk prediction nomogram. Discrimination [area under the curve (AUC)] and calibration were further performed to assess the validation of risk prediction nomogram in the training set, and then validated by the validation set. RESULTS: A total of 214,764 eligible subjects were included, with a mean age of 55.19 years. Subjects were randomly divided into the training (107,382) and validation (107,382) sets. Elder age, being male, a low education level, family history of lung cancer, history of tuberculosis, and without a history of hyperlipidemia were the independent risk factors for lung cancer. Using these six variables, we plotted 1-year, 3-year, and 5-year lung cancer risk prediction nomogram. The AUC was 0.753, 0.752, and 0.755 for the 1-, 3- and 5-year lung cancer risk in the training set, respectively. In the validation set, the model showed a moderate predictive discrimination, with the AUC was 0.668, 0.678, and 0.685 for the 1-, 3- and 5-year lung cancer risk. CONCLUSIONS: We developed and validated a simple and non-invasive lung cancer risk model in non-smokers. This model can be applied to identify and triage patients at high risk for developing lung cancers in non-smokers.

Evaluation of a Low-Dose Computed Tomography Lung Cancer Screening Program in Henan, China.

Importance: Lung cancer screening has been widely implemented in Europe and the US. However, there is little evidence on participation and diagnostic yields in population-based lung cancer screening in China. Objective: To assess the participation rate and detection rate of lung cancer in a population-based screening program and the factors associated with participation. Design, Setting, and Participants: This cross-sectional study used data from the Cancer Screening Program in Urban China from October 2013 to October 2019, with follow-up until March 10, 2020. The program is conducted at centers in 8 cities in Henan Province, China. Eligible participants were aged 40 to 74 and were evaluated for a high risk for lung cancer using an established risk score system. Main Outcomes and Measures: Overall and group-specific participation rates by common factors, such as age, sex, and educational level, were calculated. Differences in participation rates between those groups were compared. The diagnostic yield of both screening and nonscreening groups was calculated. Results: The study recruited 282 377 eligible participants and included 55 428 with high risk for lung cancer; the mean (SD) age was 55.3 (8.1) years, and 34 966 participants (63.1%) were men. A total of 22 260 participants underwent LDCT (participation rate, 40.16%; 95% CI, 39.82%-40.50%). The multivariable logistic regression model showed that female sex (odds ratio [OR], 1.64; 95% CI, 1.52-1.78), former smoking (OR, 1.26; 95% CI, 1.13-1.41), lack of physical activity (OR, 1.19; 95% CI, 1.14-1.24), family history of lung cancer (OR, 1.73; 95% CI, 1.66-1.79), and 7 other factors were associated with increased participation of LDCT screening. Overall, at 6-year follow-up, 78 participants in the screening group (0.35%; 95% CI, 0.29%-0.42%) and 125 in the nonscreening group (0.38%; 95% CI, 0.33%-0.44%) had lung cancer detected, which resulted in an odds ratio of 0.93 (95% CI, 0.70-1.23; P = .61). Conclusions and Relevance: The low participations rate in the program studied suggests that an improved strategy is needed. These findings may provide useful information for designing effective population-based lung cancer screening strategies in the future.

Zero-frequency and slow elastic modes in phononic monolayer granular membranes.

We theoretically study the dispersion properties of elastic waves in hexagonal and honeycomb monolayer granular membranes with either out-of-plane or in-plane particle motion. The particles interact predominantly via normal and transverse contact rigidities. When rotational degrees of freedom are taken into account, the bending and torsional rigidities of the intergrain contacts can control some of the phononic modes. The existence of zero-frequency modes, zero-group-velocity modes and their transformation into slow propagating phononic modes due to weak bending and torsional intergrain interactions are investigated. We also study the formation and manipulation of Dirac cones and multiple degenerated modes. This could motivate variety of potential applications in elastic waves control by manipulating the contact rigidities in granular phononic crystals.

Polarization-controllable Airy beams generated via a photoaligned director-variant liquid crystal mask.

Researches on Airy beams have grown explosively since the first demonstration in 2007 due to the distinguishing properties of nondiffraction, transverse acceleration and self-healing. To date, a simple and compact approach for generating Airy beams in high quality and efficiency has remained challenging. Here, we propose and demonstrate a liquid crystal (LC) polarization Airy mask (PAM) featured by spatially variant LC azimuthal director. The PAM is fabricated through photoaligning LC via a polarization-sensitive alignment agent suophonic azo dye SD1. Thanks to the special design, a novel feature of polarization-controllable switch between dual Airy beams of orthogonal circular polarization is presented. The molecular-level continuity of LC director significantly improves the quality and efficiency of resultant Airy beams. Besides, the PAM can handle intense light due to the absence of absorptive electrodes. Additional merits of compact size, low cost and broad wavelength tolerance are also exhibited. This work settles a fundamental requirement for Airy beam applications of optical manipulations, biology science and even some uncharted territories.

Emodin ameliorates high glucose induced-podocyte epithelial-mesenchymal transition in-vitro and in-vivo.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) is a potential pathway leading to podocyte depletion and proteinuria in diabetic kidney disease (DKD). Here, we investigated the protective effects of Emodin (EMO) on high glucose (HG) induced-podocyte EMT in-vitro and in-vivo. METHODS: Conditionally immortalized mouse podocytes were exposed to HG with 30 µg /ml of EMO and 1 µmol/ml of integrin-linked kinase (ILK) inhibitor QLT0267 for 24 h. Streptozotocin (STZ)-induced diabetic rats were treated with EMO at 20 mg· kg(-1)· d(-1) and QLT0267 at 10 mg· kg(-1)· w(-1) p.o., for 12 weeks. Albuminuria and blood glucose level were measured. Immunohistochemistry, immunofluorescence, western blotting and real-time PCR were used to detect expression of ILK, the epithelial marker of nephrin and the mesenchymal marker of desmin in-vitro and in-vivo. RESULTS: HG increased podocyte ILK and desmin expression while decreased nephrin expression. However, EMO significantly inhibited ILK and desmin expression and partially restored nephrin expression in HG-stimulated podocytes. These in-vitro observations were further confirmed in-vivo. Treatment with EMO for 12 weeks attenuated albuminuria, renal histopathology and podocyte foot process effacement in diabetic rats. EMO also repressed renal ILK and desmin expression, preserved nephrin expression, as well as ameliorated albuminuria in STZ-induced diabetic rats. CONCLUSION: EMO ameliorated glucose-induced EMT and subsequent podocyte dysfunction partly through ILK and desmin inhibition as well as nephrin upregulatiotion, which might provide a potential novel therapeutic option for DKD.

Acoustic rainbow trapping by coiling up space.

We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

Accidental degeneracy of double Dirac cones in a phononic crystal.

Artificial honeycomb lattices with Dirac cone dispersion provide a macroscopic platform to study the massless Dirac quasiparticles and their novel geometric phases. In this paper, a quadruple-degenerate state is achieved at the center of the Brillouin zone in a two-dimensional honeycomb lattice phononic crystal, which is a result of accidental degeneracy of two double-degenerate states. In the vicinity of the quadruple-degenerate state, the dispersion relation is linear. Such quadruple degeneracy is analyzed by rigorous representation theory of groups. Using k·p method, a reduced Hamiltonian is obtained to describe the linear Dirac dispersion relations of this quadruple-degenerate state, which is well consistent with the simulation results. Near such accidental degeneracy, we observe some unique properties in wave propagating, such as defect-insensitive propagating character and the Talbot effect.