In spinful electronic systems, time-reversal symmetry makes that all Kramers pairs at the time-reversal-invariant momenta are Weyl points (WPs) in chiral crystals. Here, we find that such ...symmetry-enforced WPs can also emerge in bosonic systems (e.g. phonons and photons) due to nonsymmorphic symmetries. We demonstrate that for some nonsymmorphic chiral space groups, several high-symmetry k-points can host only WPs in the phononic systems, dubbed symmetry-enforced Weyl phonons (SEWPs). The SEWPs, enumerated in Table 1, are pinned at the boundary of the three-dimensional (3D) Brillouin zone (BZ) and protected by nonsymmorphic crystal symmetries. By performing first-principles calculations and symmetry analysis, we propose that as an example of SEWPs, the twofold degeneracies at P are monopole WPs in K2Sn2O3 with space group 199. The two WPs of the same chirality at two nonequivalent P points are related by time-reversal symmetry. In particular, at ~17.5 THz, a spin-1 Weyl phonon is also found at H, since two Weyl phonons at P carrying a non-zero net Chern number cannot exist alone in the 3D BZ. The significant separation between P and H points makes the surface arcs long and clearly visible. Our findings not only present an effective way to search for WPs in bosonic systems, but also offer some promising candidates for studying monopole Weyl and spin-1 Weyl phonons in realistic materials.
In order to raise the accuracy of the circular gratings angle-measuring system, a comprehensive error model is established, and a novel compensation method is proposed. Firstly, many error sources, ...including the rotary errors of axis system, the installation eccentricity and the inclination of the circular grating disc, the graduation line error of the circular grating disc, and the installation error of the multiple readingheads of the high precision circular gratings angle-measuring system are comprehensively taken into consideration. Secondly, the position and attitude errors are propagated to the angular position outputs, thus the mathematical relationships between error sources and the angular position error are established. Aiming at multiple readingheads system, the mechanism of influence of the error sources on the angular position error is unveiled, and the mechanical error identification and reduction method is proposed. After that, a checking system with a 23-mirrored polygon and an autocollimator is set up, and the complete combinatorial method of separating the angular position errors from the readouts of the autocollimator precisely is used. Finally, the angular position error compositions are separated by the harmonic analysis method, and the concerned error coefficients are compensated. The experimental results show that the nominal indication interval value of the angular position errors is reduced to 0.23" by the mechanical error reduction method, and then the nominal indication interval value of the angular position errors is reduced to 0.12" by software measurement method. And the two sets’ repeatability of the separated biases of the 23-mirrored polygon before and after compensating is 95%.
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•An error model designed includes all error sources in angle-measuring system.•Radial error, eccentricity errors and indicating grating installing errors can be reduced.•Mechanical compensation method and software compensation method are combined to further improve angle measurement system accuracy.•Consistency of polygon separated biases in different initial angular position validates the effectiveness.•Proposed method is suitable for any angle measurement system.
Background
Nuclear grade is of importance for treatment selection and prognosis in patients with clear cell renal cell carcinoma (ccRCC).
Purpose
To develop and validate an MRI‐based radiomic model ...for preoperative predicting WHO/ISUP nuclear grade in ccRCC.
Study Type
Retrospective.
Population
In all, 379 patients with histologically confirmed ccRCC. Training cohort (n = 252) and validation cohort (n = 127) were randomly assigned.
Field Strength/Sequence
Pretreatment 3.0T renal MRI. Imaging sequences were fat‐suppressed T2WI, contrast‐enhanced T1WI, and diffusion weighted imaging.
Assessment
Three prediction models were developed using selected radiomic features, radiomic and clinicoradiologic characteristics, and a model containing only clinicoradiologic characteristics. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were used to assess the predictive performance of these models in predicting high‐grade ccRCC.
Statistical Tests
The least absolute shrinkage and selection operator (LASSO) and minimum redundancy maximum relevance (mRMR) method were used for the selection of radiomic features and clinicoradiologic characteristics, respectively. Multivariable logistic regression analysis was used to develop the radiomic signature of radiomic features and clinicoradiologic model of clinicoradiologic characteristics.
Results
The radiomic signature showed good performance in discriminating high‐grade (grades 3 and 4) from low‐grade (grades 1 and 2) ccRCC, with sensitivity, specificity, and AUC of 77.3%, 80.0%, and 0.842, respectively, in the validation cohort. The radiomic model, combining radiomic signature and clinicoradiologic characteristics, displayed good predictive ability for high‐grade with sensitivity, specificity, and accuracy of 63.6%, 93.3%, and 88.2%, respectively, in the validation cohort. The radiomic model showed a significantly better performance than the clinicoradiologic model (P < 0.05).
Data Conclusion
Multiparametric MRI‐based radiomic model can predict WHO/ISUP grade in patients with ccRCC with satisfying performance, and thus could help the physician to improve treatment decisions.
Level of Evidence
3
Technical Efficacy Stage
2
The leaf area index（LAI） is an important vegetation parameter,which is used widely in many applications.Remote sensing techniques are known to be effective but inexpensive methods for estimating the ...LAI of crop canopies.During the last two decades,hyperspectral remote sensing has been employed increasingly for crop LAI estimation,which requires unique technical procedures compared with conventional multispectral data,such as denoising and dimension reduction.Thus,we provide a comprehensive and intensive overview of crop LAI estimation based on hyperspectral remote sensing techniques.First,we compare hyperspectral data and multispectral data by highlighting their potential and limitations in LAI estimation.Second,we categorize the approaches used for crop LAI estimation based on hyperspectral data into three types：approaches based on statistical models,physical models（i.e.,canopy reflectance models）,and hybrid inversions.We summarize and evaluate the theoretical basis and different methods employed by these approaches（e.g.,the characteristic parameters of LAI,regression methods for constructing statistical predictive models,commonly applied physical models,and inversion strategies for physical models）.Thus,numerous models and inversion strategies are organized in a clear conceptual framework.Moreover,we highlight the technical difficulties that may hinder crop LAI estimation,such as the ＂curse of dimensionality＂ and the ill-posed problem.Finally,we discuss the prospects for future research based on the previous studies described in this review.
MicroRNAs (miRNAs) are a novel class of small non-coding RNAs that negatively regulate gene expression at the posttranscriptional level by binding to the 3′ untranslated region of target mRNAs ...leading to their translational inhibition or sometimes degradation. We uncovered a previously unknown alteration in temporal expression of a large set of miRNAs following a contusive spinal cord injury (SCI) in adult rats using microarray analysis. These altered miRNAs can be classified into 3 categories: (1) up-regulation, (2) down-regulation and (3) an early up-regulation at 4 h followed by down-regulation at 1 and 7 days post-SCI. The bioinformatics analysis indicates that the potential targets for miRNAs altered after SCI include genes encoding components that are involved in the inflammation, oxidation, and apoptosis that are known to play important roles in the pathogenesis of SCI. These findings suggest that abnormal expression of miRNAs may contribute to the pathogenesis of SCI and are potential targets for therapeutic interventions following SCI.
The population of patients with huge hepatocellular carcinoma (H‐HCC diameter > 10.0 cm) is an odd group that is not well adjudicated in the current staging systems, whose prognosis after curative ...resection varies. We aimed to develop novel models to predict the long‐term outcomes of patients with H‐HCC without portal vein tumor thrombus after hepatectomy. There were 1076 H‐HCC patients enrolled who underwent curative liver resection in five institutions in China. In total, 670 patients were recruited from our center and randomly divided into the training cohort (n = 502) and internal validation (n = 168) cohorts. Additionally, 406 patients selected from other four centers as the external validation cohort. Novel models were constructed based on independent preoperative and postoperative predictors of postsurgical recurrence (PSR) and postsurgical mortality (PSM) determined in multivariable cox regression analysis. The predictive accuracy and discriminative ability of the model were measured using Harrell's concordance index (C index) and calibration curve and compared with five conventional HCC staging systems. PSR model and PSM model were constructed based on tumor number, microscopic vascular invasion, tumor differentiation, preoperative alpha‐fetoprotein level, albumin‐bilirubin grade, liver segment invasion, neutrophil‐to‐lymphocyte ratio or platelet‐to‐neutrophil ratio, and surgical margin or intraoperative blood transfusion. The C‐indexes were 0.84 (95% CI, 0.78‐0.90) and 0.85 (95% CI, 0.78‐0.91) for the PSR and PSM models, respectively, which were substantially higher than those of the five conventional HCC staging systems (0.63‐0.75 for PSR; 0.66‐0.77 for PSM). The two novel models achieved more accurate prognostic predictions of PSR and PSM for H‐HCC patients after curative liver resection.
What's new?
There is no individual prognostic score or tool to predict the prognosis of patients with huge hepatocellular carcinoma (H‐HCC, diameter > 10.0 cm) after hepatectomy. In this large retrospective cohort study, the authors developed two novel models which could accurately and objectively predict postsurgical recurrence and mortality for patients with H‐HCC after curative liver resection. The models, which are publicly available, are based on eight conventional and easily obtainable clinicopathological and surgical variables. The models could be used to guide postoperative monitoring for patients with a high risk of recurrence, and may thus potentially contribute to improving survival in these patients.
Absence of any surface arc state has been regarded as the fundamental property of singular Weyl points, because they are circumvented from the Nielsen‐Ninomiya no‐go theorem. In this work, through ...systematic investigations on topological properties of isolated Weyl phonons (IWPs) surrounded by closed Weyl nodal walls (WNWs), which are located at the Brillouin zone (BZ) boundaries of bosonic systems, it uncovers that a new kind of phononic surface state, that is, the multi‐fold fan‐shape surface state named by us, is exhibited to connect the projections of IWP and WNWs. Importantly, the number of fan leaves in this surface state is associated with the Chern number of IWP. Moreover, the topological features of charge‐two IWP in K2Mg2O3 (SG No. 96) and charge‐four IWP in Nb3Al2N (SG No. 213) confirm further the above fundamental properties of this kind of surface state. The theoretical work not only provides an effective way to seek for IWPs as well as to determine their Chern number in real materials, but also uncovers a new class of surface states in the topological Weyl complex composed of IWPs and WNWs.
We uncover that a new kind of phononic surface state, that is, the multi‐fold fan‐shape surface state named by us, is exhibited to connect the projections of isolated Weyl point (IWP) and the surrounded Weyl nodal walls. Importantly, the number of fan leaves in this surface state is associated with the Chern number of IWP.
Sustained hyperglycaemia and hyperlipidaemia incur endoplasmic reticulum stress (ER stress) and reactive oxygen species (ROS) overproduction in pancreatic β‐cells. ER stress or ROS causes c‐Jun ...N‐terminal kinase (JNK) activation, and the activated JNK triggers apoptosis in different cells. Nuclear receptor subfamily 4 group A member 1 (NR4A1) is an inducible multi‐stress response factor. The aim of this study was to explore the role of NR4A1 in counteracting JNK activation induced by ER stress or ROS and the related mechanism. qPCR, Western blotting, dual‐luciferase reporter and ChIP assays were applied to detect gene expression or regulation by NR4A1. Immunofluorescence was used to detect a specific protein expression in β‐cells. Our data showed that NR4A1 reduced the phosphorylated JNK (p‐JNK) in MIN6 cells encountering ER stress or ROS and reduced MKK4 protein in a proteasome‐dependent manner. We found that NR4A1 increased the expression of cbl‐b (an E3 ligase); knocking down cbl‐b expression increased MKK4 and p‐JNK levels under ER stress or ROS conditions. We elucidated that NR4A1 enhanced the transactivation of cbl‐b promoter by physical association. We further confirmed that cbl‐b expression in β‐cells was reduced in NR4A1‐knockout mice compared with WT mice. NR4A1 down‐regulates JNK activation by ER stress or ROS in β‐cells via enhancing cbl‐b expression.
Abstract
The Yarkovsky effect causes the semimajor axis drift of near-Earth asteroids. The drift can be detected by a precise orbit determination process. Using the proposed algorithm, 2233 out of ...27,078 near-Earth asteroids are chosen as the initial candidates. Out of these initial candidates, 769 have a measurable Yarkovsky effect with a signal-to-noise ratio (S/N) larger than 1, and 166 have a measurable Yarkovsky effect with an S/N larger than 3. The ratio between retrograde and prograde near-Earth asteroids is plotted with respect to their size. An average ratio of 2 is found for asteroids with an absolute magnitude between 14 and 21. The measurement work is carried out based on orbit determination software developed by the authors that considers a high-precision dynamical model.
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