Strength characteristics and failure behavior of ubiquitous-joint rock-like specimens under compressive-shear stress: experimental study and digital speckle correlation method

In nature, rock mass is subjected to compression-shear effect, so it is very important to study the failure mode and mechanical properties of fractured rock mass under compression-shear effect. In order to study the influence of joint inclination on strength characteristics and failure modes of rock mass under different compression-shear angles, a series of compression-shear tests were carried out. The specimens are made of a certain proportion of fine sand, cement and water. The joints are prefabricated by inserting mica sheets and the inclination angle of joints is 0°, 15°, 30°, 45°, 60°, 75°, 90°. Digital speckle correlation method is used to analyze the strain field of the specimen during the whole loading process. The specimens are speckled on the opposite side before the experiment. In the experiment, the front and back sides of the specimen are monitored by the camera, and the images are analyzed after the experiment. The result shows that: 1) The peak shear strength of specimens mainly increases with the increase of joint inclination angle; 2) The weakening degree of shear strength caused by joint inclination angle of specimens tends to increase as the compression-stress ratio increases; and 3) The failure modes can be classified into four types: coplanar shear failure mode, inclined shear failure mode, quasi-complete shear failure mode and step shear failure mode. The digital speckle strain images better prove the failure modes obtained from the experiment

Diagnostic and prognostic role of circRNAs in pancreatic cancer: a meta-analysis

BackgroundCircular RNAs (circRNAs) are types of endogenous noncoding RNAs produced by selective splicing that are expressed highly specifically in various organisms and tissues and have numerous clinical implications in the regulation of cancer development and progression. Since circRNA is resistant to digestion by ribonucleases and has a long half-life, there is increasing evidence that circRNA can be used as an ideal candidate biomarker for the early diagnosis and prognosis of tumors. In this study, we aimed to reveal the diagnostic and prognostic value of circRNA in human pancreatic cancer (PC).MethodsA systematic search for publications from inception to 22 July 2022 was conducted on Embase, PubMed, Web of Science (WOS), and the Cochrane Library databases. Available studies that correlated circRNA expression in tissue or serum with the clinicopathological, diagnostic, and prognostic values of PC patients were enrolled. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to evaluate clinical pathological characteristics. Area under the curve (AUC), sensitivity, and specificity were adopted to assess diagnostic value. Hazard ratios (HRs) were utilized to assess disease-free survival (DFS) and overall survival (OS).ResultsThis meta-analysis enrolled 32 eligible studies, including six on diagnosis and 21 on prognosis, which accounted for 2,396 cases from 245 references. For clinical parameters, high expression of carcinogenic circRNA was significantly associated with degree of differentiation (OR = 1.85, 95% CI = 1.47–2.34), TNM stage (OR = 0.46, 95% CI = 0.35–0.62), lymph node metastasis (OR = 0.39, 95% CI = 0.32–0.48), and distant metastasis (OR = 0.26, 95% CI = 0.13–0.51). As for clinical diagnostic utility, circRNA could discriminate patients with pancreatic cancer from controls, with an AUC of 0.86 (95% CI: 0.82–0.88), a relatively high sensitivity of 84%, and a specificity of 80% in tissue. In terms of prognostic significance, carcinogenic circRNA was correlated with poor OS (HR = 2.00, 95% CI: 1.76–2.26) and DFS (HR = 1.96, 95% CI: 1.47–2.62).ConclusionIn summary, this study demonstrated that circRNA may act as a significant diagnostic and prognostic biomarker for pancreatic cancer

Molecular landscape and clinical significance of exon 11 mutations in KIT gene among patients with gastrointestinal stromal tumor: a retrospective exploratory study

ObjectiveThis aim of this study was to investigate the prognostic significance of KIT exon 11 mutation subtypes in patients with GISTs.MethodsA total of 233 consecutive patients diagnosed with GISTs at the First Affiliated Hospital of Zhengzhou University from January 2013 to August 2018 were included in this study. The prevalence and mutation landscape of exon 11 in KIT was presented. The clinicopathological characteristics and prognosis among the different mutation subtypes were analyzed. All the statistical analyses were performed by SPSS22.0.ResultsSomatic mutational analysis indicated that point mutations were the most frequently detected mutations followed by deletions & compound mutations and insertion and tandem duplication mutations in the stomach. Point mutations showed a low mitotic count and a high risk of recurrence, and deletions and compound mutations have a high mitotic count while insertions and tandem duplication mutations showed a low mitotic count with an intermediate recurrence risk. Point mutations and deletions frequently occurred in sequence region codons 550-560 of exon 11, while compound mutations, insertion, and tandem duplication were mainly detected in codons 557-559, 572-580, and 577-581, respectively. The multi-variation analysis demonstrated that tumor diameter and high recurrence risk groups had worse prognostic values. However, mutation types were not significant predictors of relapse-free survival (RFS) in GISTs. Survival analysis suggested no significant difference in RFS between the 557/558 deletion and the other deletions.ConclusionThis study suggested that mutations in exon 11 of the KIT gene were common with intermediate/high recurrence risk in GISTs patients. Tumor diameter ≥5 cm, and deletions mutations might predict a worse prognosis

Improved spring temperature reconstruction using earlywood blue intensity in southeastern China

Because instrumental observations are too short to fully represent long-term natural variability, high-resolution temperature proxy records are essential to understanding past climate and assessing current climate variability in the context of long-term patterns. In the subtropics, progress in this field has been hampered by a relative lack of long and truly temperature-sensitive proxy records. In this study, we provide an assessment of the dendroclimatic potential of blue intensity (BI) and ring-width (RW) measurements from two hot/humid Pinus massoniana sites in China. Our results show that RW exhibits a significant (p < .05) response to precipitation over a hydrological year (previous November to October) and to temperature over the winter–spring season (January to March). We find the earlywood blue intensity parameter to be the most robust parameter for reconstruction purposes; over the 1916–2015 period, it explains 36% of regional-scale spring season (March–May) temperature variance. Strong agreements between the current reconstruction and observed temperature over a large area of southeastern China implied that our reconstruction exhibited high reliability and large spatial representation. As expected, our reconstructed temperature data are directly correlated with El Niño–Southern Oscillation. These results suggest that there is great potential to use BI to advance our understanding of temperature variability in regions hot and humid climate regimes. However, more studies are needed to understand (1) which subtropical tree species will be appropriate for use and (2) how to overcome biases from differential staining between sapwood and heartwood

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Sobre el Desarrollo Futuro de China- Argentina en la Cooperación de la Franja y la Ruta y la Asociación Estratégica Integral

Como extensión “natural” de la Ruta de la Seda Marítima del Siglo XXI, América Latina es participante indispensable e importante en la construcción de la Iniciativa de la Franja y la Ruta. En la región, Argentina juega un papel esencial en la mencionada Iniciativa de la Franja y la Ruta. El año 2022 marca el 50 aniversario del establecimiento de relaciones diplomáticas entre China y Argentina. Durante el último medio siglo, ambos estados han sostenido una política de solidaridad y de asistencia mutua. En julio de 2014, el presidente chino Xi Jinping realizó una visita de Estado a Argentina, durante la cual ambas partes anunciaron el establecimiento de una Asociación Estratégica Integral. En 2021, China se convirtió en el segundo socio comercial más grande de Argentina, y Argentina escaló al puesto de quinto socio comercial más grande de China en América Latina. Se cree firmemente que la cooperación integral entre los dos países a través de la Iniciativa de la Franja y la Ruta promoverá aún más el desarrollo de la cooperación económica y comercial bilateral en una dirección que sea más integral, profunda, equilibrada, sostenible y beneficiosa para todos

Aftereffect of Adaptation to Illusory Brightness

Several figures are known to induce illusory brightness. We tested whether adaptation to illusory brightness produced an aftereffect in brightness. After viewing a gray square area having illusory brightness (e.g., due to brightness contrast or illusory contours) for ten seconds, the illusion-inducing surround vanished. After three seconds, subjects reported whether the square area was seen as brighter than, darker than, or the same brightness as a control gray square area. The luminance of the tested square area was physically unchanged. The results show that when the black surround inducing brightness contrast suddenly became gray (i.e., vanished), the center gray square tended to look darker than a control gray square. Similarly, after viewing a subjective square consisting of black-line terminations, the square area tended to look darker than the control even though the afterimage of the lines could not be seen. These results indicate that induced or illusory brightness causes an aftereffect in brightness regardless of the appearance of negative afterimages of the illusion-inducing components

Image Retrieval Based on Discrete Fractional Fourier Transform Via Fisher Discriminant

© 2016, Springer Science+Business Media New York.Discrete fractional Fourier transform (DFrFT) is a powerful signal processing tool. This paper proposes a method for DFrFT-based image retrieval via Fisher discriminant and 1-NN classification rule. First, this paper proposes to extend the conventional discrete Fourier transform (DFT) descriptors to the DFrFT descriptors to be used for representing the edges of images. The DFrFT descriptors extracted from the training images are employed to construct a dictionary, for which the corresponding optimal rotational angles of the DFrFTs are required to be determined. This dictionary design problem is formulated as an optimization problem, where the Fisher discriminant is the objective function to be minimized. This optimization problem is nonconvex (Guan et al. in IEEE Trans Image Process 20(7):2030–2048, 2011; Ho et al. in IEEE Trans Signal Process 58(8):4436–4441, 2010). Furthermore, both the intraclass separation and interclass separation of the DFrFT descriptors are independent of the rotational angles if these separations are defined in terms of the 2-norm operator. To tackle these difficulties, the 1-norm operator is employed. However, this reformulated optimization problem is nonsmooth. To solve this problem, the nondifferentiable points of the objective function are found. Then, the stationary points between any two consecutive nondifferentiable points are identified. The objective function values are evaluated at these nondifferentiable points and these stationary points. The smallest L objective function values are picked up and the corresponding rotational angles are determined, which are then used to construct the dictionary. Here, L is the total number of the rotational angles of the DFrFTs used to construct the dictionary. Finally, an 1-NN classification rule is applied to perform the image retrieval. Application examples and experimental results show that our proposed method outperforms the conventional DFT approach

Numerical simulation of sedimentation in the Central Canyon of Lingshui area, Qiongdongnan Basin

Deepwater canyon is now the focus of the research field of offshore oil and gas exploration.In the Qiongdongnan Basin of the northwestern South China Sea, several deepwater exploration boreholes have been deployed in the Central Canyon to reveal the lithologic hydrocarbon reservoir of sediment infill therein.However, due to the relatively limited number of these boreholes, the large distance between each borehole, as well as the low resolution of seismic data, the issues regarding the superposition relationship between different sandstone bodies within the canyon, their contact relationship with boundaries, and sedimentary evolution remain poorly understood, which severely hinder the delicate characterization of reservoir physical properties.This study investigates the Lingshui area of the Central Canyon from the perspective of numerical simulation of sedimentation.Geological and mathematical models are established based on the specific geological observations.The hydrodynamic simulation software ANSYS FLUENT is used for the forward modeling of multiple sedimentary stages and sandstone bodies with different initial conditions (e.g., provenance and inlet velocity) to reveal the geometry of modeled turbidite sedimentation, including the horizontal and vertical distribution patterns of sandstone bodies.The simulation results show that: Within the straight section of the canyon, the flow rate and intensity of the turbidity current gradually decrease due to the effect of substrate friction; Relatively coarse and fine particles can be deposited on the substrate and suspended along with the vortex at the head of the turbidity flow, respectively; Within the narrow section of the canyon, the turbulence of the head of the turbidity flow is strong enough to erode the canyon wall and also shift the strike of the canyon.Suspended particles can be affected by centrifugation force to form the overflow sedimentation; In addition, the results show a vertical heterogeneity of sandstone bodies distributed within the canyon: sandstone bodies are usually interlayered by mudstone that features a small thickness and poor lateral continuity.A comparison with the available seismic and borehole data shows the validity of the obtained simulation results.This study attempts to reveal the hydrodynamic processes in terms of different sedimentary stages and sandstone bodies, and then to predict the configuration of sandstone bodies that provides a favorable basis for reservoir prediction