Dynamic mechanical properties of different types of rocks under impact loading.

To study the mechanical properties of different types of rocks under impact loading, static mechanical parameter tests and split-Hopkinson pressure bar (SHPB) dynamic impact experiments were conducted on five typical rock specimens. The mechanical properties and failure modes of different rock specimens under the same static and dynamic loading were investigated. The differences between numerical simulation results and laboratory test results under different constitutive models in LS-DYNA were also compared and analyzed. The results show that with the increase of SHPB impact pressure (0.5-0.8 MPa), the stress peak values of granite, marble, and limestone also increase, while gypsum and reef limestone follow no particular trend. At the same time, both HJC and RHT constitutive models can simulate the laboratory impact test results of granite, marble, and limestone, however, the gypsum and reef limestone are not modelled by the HJC constitutive model, while the RHT constitutive model can describe the deformation-damage-failure process of rock specimens with different strengths. Therefore, the RHT model can better reflect the real deformation and failure of rocks.

Shaping characteristics of excavation contours in sequential controlled fracture blasting of rock-anchored beams in Shuangjiangkou underground powerhouse.

Influences of high in-situ stress generally need to be considered when excavating deep underground caverns. The dynamic fracture behaviors of rocks under blast loads were investigated by using the rock-anchored beam excavation in underground powerhouses of Shuangjiangkou Hydropower Station in Sichuan Province, China as the engineering background. To solve the problems of the poor blasting breakage effect of rocks and the difficulty in protecting surrounding rocks during excavation, mechanical properties of granite under static and dynamic loads were investigated and the sequential controlled fracture blasting (SCFB) method was adopted during in-situ tests. Based on the Riedel-Hiermaier-Thoma constitutive model and the strength criterion, software LS-DYNA was employed to simulate the dynamic propagation of blasting-induced cracks. The contour shaping effect obtained via numerical simulation is generally consistent with the test results. The results show that SCFB can to some extent control the direction of crack initiation and rock fracture behavior of the blasthole wall cracks and the spacing of successive bursting holes is about 10 times the diameter of the blastholes when the cracks between the blastholes are shaped the best effect. Moreover, the magnitude and direction of principal in-situ stress can both affect the propagation path and length of blasting-induced cracks. The results of the research on the excavation and construction of deeply buried underground caverns have a certain reference value.

Prognostic impact of the Fusobacterium nucleatum status in colorectal cancers.

To investigate the clinicopathological features and prognostic impact of Fusobacterium nucleatum (F nucleatum) status in patients with colorectal cancer (CRC) and its relationships with microsatellite instability (MSI) status.Retrospective analysis of consecutive 91 CRC tissues from surgically resected specimens of stage III or high-risk stage II CRC patients who had received curative surgery in Wuhan Union Hospital from January, 2017 to January, 2019 was conducted. F nucleatum DNA was quantitatively measured and classified into 1 of the 2 categories: F nucleatum-high, or F nucleatum-low/negative. The Cox risk ratio model analysis was performed to identify independent risk factors of F nucleatum. F nucleatum-high group was compared with the F nucleatum-low/negative group with respect to clinicopathological features and their relationships with MSI status. Kaplan-Meier method and log-rank test were used for univariate analysis of prognostic factors in patients with CRC.The number of total lymph node acquisition and positive lymph nodes, neurological invasion, vascular tumor thrombus were higher in F nucleatum-high group (27.44 ±â€Š25.213 vs 20.70 ±â€Š10.141; P = .018; 3.80 ±â€Š7.974 vs 1.74 ±â€Š3.531; P = .001; 68.0% vs 33.3%; P = .003; 60.0% vs 25.8%; P = .002). Moreover, microsatellite mutations were more frequent in patients with F nucleatum-high (84.0% vs 60.6%; P = .034). A higher abundance of F nucleatum in CRC is associated with a shorter survival time. The F nucleatum status, peripheral nerve invasion, vascular tumor thrombus, lymph node metastasis, and TNM staging were related factors affecting the prognosis of patients with CRC. The Cox risk ratio model analysis showed that the F nucleatum (odds ratio [OR] 2.094, 95% confidence interval [CI] 1.178-8.122, P = .032) and MSI status (OR 2.243, 95% CI 1.136-5.865, P = 0.039) were independent prognostic factors.Intratumoral F nucleatum load has a poor prognostic effect of CRC by increasing nerve invasion, vascular tumor thrombus, and microsatellite mutation.

Long non-coding RNA SNHG16 affects cell proliferation and predicts a poor prognosis in patients with colorectal cancer via sponging miR-200a-3p.

Previous study has explored that SNHG16, a long non-coding RNA (lncRNA), mediated cell growth and proliferation. Yet, the role of SNHG16 in human colorectal cancer (CRC) still remains to be explored. Therefore, we conducted the present study to explore the functions of SNHG16 in CRC. In the present study, SNHG16 was significantly up-regulated in CRC tissues and cell lines. Gain- and loss-of-function of SNHG16 further presented that SNHG16 promoted the progression of CRC cells, including proliferation, migration, and invasion. Further, in vivo study also revealed that overexpression of SNHG16 could promote tumor growth. Bioinformatics analysis and luciferase reporter assay showed that SNHG16 was a direct target of miR-200a-3p. MiR-200a-3p was inversely correlated with SNHG16 expression in CRC tissues. In brief, the above results elucidate the important role of SNHG16 in CRC tumorigenesis, suggesting that SNHG16 might be quite vital for the diagnosis and development of CRC.

Homoepitaxial regrowth habits of ZnO nanowire arrays.

Synthetic regrowth of ZnO nanowires [NWs] under a similar chemical vapor transport and condensation [CVTC] process can produce abundant ZnO nanostructures which are not possible by a single CVTC step. In this work, we report three different regrowth modes of ZnO NWs: axial growth, radial growth, and both directions. The different growth modes seem to be determined by the properties of initial ZnO NW templates. By varying the growth parameters in the first-step CVTC process, ZnO nanostructures (e.g., nanoantenna) with drastically different morphologies can be obtained with distinct photoluminescence properties. The results have implications in guiding the rational synthesis of various ZnO NW heterostructures.

The effects of cholecystojejunostomy and biliary drainage on biliary motor.

Simulating physiological neuronal and hormonal conditions during digestive and interdigestive periods, the study identified the changes of the motility of biliary system including bile duct and sphincter of Oddi (SO) before and after cholecystojejunostomy. Thirty-five rabbits were divided into five groups randomly. The experimental groups received the venous injection of CCK 10 ng/kg, erythromycin 10 mg/kg, atropine 3 micrograms/kg and L-NAME 10 mg/kg respectively. Each rabbit underwent manometry through introducing a three-lumen catheter via the papilla retrogradely, using the low-compliance papillary infusion system. Then the gallbladder and the upper segment of the jejunum was anastomosed and the manometric procedures repeated after one week. SO basal pressure was increased, contraction amplitude decreased, contraction time shortened after cholecystojejunostomy. L-NAME, CCK and erythromycin could all excite SO. L-NAME could increase basal pressure and contraction amplitude, CCK increase basal pressure contraction amplitude and frequency, and erythromycin increase contraction amplitude, respectively. But comparing with that before cholecystojejunostomy, the increasing extent was decreased. The tensional and spontaneous contractions of the SO were under the control of the neural and hormonal mechanism. The anastomosis of gallbladder and jejunum and the drainage of bile made the tensional contraction stronger, but the spontaneous contraction weakened after the operation due to the decreases of the sensitivity of SO to hormonal factors. The clinical symptoms may not be relieved when the patients with SO dysfunction accepted cholecystojejunostomy.