Soil-rock mixtures (S-RMs), as a kind of special engineering geological material, need to be studied because of the special structure and complex movement mechanism of their rock blocks, their ...physical and mechanical properties, and the factors underlying rock block movement in the process of their deformation and failure. In this paper, a series of discrete-element numerical models are constructed in particle flow code software (PFC2D). First, the random structure numerical models of S-RMs with different rock block proportions are established. Then, the parameters of the soil meso-structure are inversed by the biaxial simulation test, and a series of biaxial compressive tests are performed. The characteristics of stress and strain, deformation and failure, and rock block rotation and energy evolution are systematically investigated. The results show the following. (1) As the rock block proportion (confining pressure 0.5 MPa) increases, the peak strength of increases, the fluctuations of the post-peak become more obvious, and the dilatancy of the sample increases. (2) As the rock block proportion increases, the width of the shear band increases, the distribution of cracks becomes more complex and dispersed, and the range of the shear zone increases. (3) The number of rock blocks with rotation also increases significantly as rock block proportion increases, and the rotation angles are mostly between −5° and 5°. (4) The strain energy of S-RMs with different rock block proportions follows the same change rule as axial strain, showing a trend of first increasing and then decreasing, like the stress–strain curve.
Soil-rock mixtures (S-RMs), as special engineering geological materials, are widely distributed in mountainous regions and are important hosts of slope disasters. Stability studies are very important ...for predicting S-RM slope safety during the construction and operation of engineering projects. To investigate S-RM slope stability considering the spatial distribution of oversized rock blocks in the slope, the distinct element method (DEM) program particle flow code in two dimensions (PFC2D) was used to analyse the stability of slopes composed of S-RMs. First, according to the stochastic approach, different numerical models of an S-RM slope were established with different oversized rock block spatial distributions. Then, the S-RM slope models were simulated, the safety factor and sliding characteristics of the slopes were analysed, and the unbalanced contact force and rotational characteristics of the oversized rock blocks were discussed. Finally, the concept of key rock blocks in S-RM slopes was proposed, and their spatial distribution characteristics and influence characteristics were summarized. The findings of this study suggest that oversized rock blocks have a certain influence on the stability of S-RM slopes.
The asphalt mixture splitting test is one of the most important methods for measuring asphalt’s tensile properties. To characterize the limitations of the traditional splitting test and the influence ...of the specimen size and loading conditions on the accuracy of the test, the factors affecting the strength of the splitting test were analyzed to reveal the splitting failure state and establish a unified representation model between the splitting and direct tensile tests. Initially, the moment of specimen cracking was taken as a key indicator, combined with image processing technology, to establish a set of criteria to judge the splitting test. Subsequently, standardized splitting tests were conducted and compared to tests of different specimen sizes and loading methods. Based on the octahedral strength theory, the stress points before and after the improved test were compared to the existing failure criteria. Direct tensile and splitting tests were conducted at different rates, and a unified strength–rate function model was established, realizing the unified representation of direct tensile and splitting tests. The research results indicate that the standardized splitting test is prone to the phenomenon wherein the specimen end face cracks before the center, affecting the accuracy of the test and potentially leading to redundant material strength evaluations. Using a loading method with a “35 mm specimen thickness” and a “0.3 mm rubber gasket + 12.7 mm arc-shaped batten” can essentially achieve the test hypothesis of “cracking at the center first”, resulting in less discrete outcomes and closer alignment to the three-dimensional stress failure state. The tensile and splitting strengths are both power function relationships with the rate as the independent variable, establishing a unified function model of the tensile and failure strengths. The research provides a more reliable testing method and calculation model for asphalt pavement structure design, and it also provides an effective basis for the improvement of splitting tests on materials such as concrete and rock.
Affected by the fluctuation in water levels in reservoir areas, the probability of potential landslide instability along reservoir banks is substantially increasing, which threatens the lives and ...property of residents along the reservoirs. In this study, the effect of reservoirs on the Dashuichong landslide in Hunan Province, China, was investigated. The geological background and failure characteristics of the landslide were presented. The crack features and surface deformation mechanisms were described in detail, and the surge characteristics of the landslide at the highest water level (333.15 m) were calculated. The deformation characteristics and failure mechanisms of the Earth’s surface and overlying buildings revealed that the instability of the landslide was mainly affected by the fluctuation in the reservoir water level and that initially the toe of the slope near the reservoir bank slipped, gradually extending to the top of the slope, forming a typical traction landslide under the influence of the reservoir water. At the highest water level (333.15 m), the landslide sliding velocity of the landslide into the reservoir was 1.43 m/s, causing the initial height of the surge to be 2.45 m and the run-up height of the surge on the reservoir dam to be approximately 3.67 m. These conditions readily induced the risk of dam overturning.
Ovarian cancer is the second most common gynecological malignancy, and one of the most deadly. The bottleneck restricting the treatment of ovarian cancer is its multi-drug resistance to chemotherapy. ...Cajanol is an isoflavone from pigeon pea (Cajanus cajan) that has been reported to have anti-tumor activity. In this work, we evaluate the effect of cajanol in reversing paclitaxel resistance of the A2780/Taxol ovarian cancer cell line
and
, and we discuss its mechanism of action. We found that 8 μM cajanol significantly restored the sensitivity of A2780/Taxol cells to paclitaxel, and
experiments demonstrated that the combination of 0.5 mM/kg paclitaxel and 2 mM/kg cajanol significantly inhibited the growth of A2780/Taxol metastatic tumors in mice. Flow cytometry, fluorescence quantitative PCR, western blotting and immunohistochemical staining methods were used to study the mechanism of reversing paclitaxel resistance with cajanol. First, we determined that cajanol inhibits paclitaxel efflux in A2780/Taxol cells by down-regulating permeability glycoprotein (P-gp) expression, and further found that cajanol can inhibit P-gp transcription and translation through the PI3K/Akt/NF-κB pathway. The results of this work are expected to provide a new candidate compound for the development of paclitaxel sensitizers.
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► Gold and graphene modified carbon ionic liquid electrode was fabricated. ► ssDNA probe was covalently-linked on the electrode to prepare the DNA biosensor. ► Polymerase chain ...reaction product of Listeria monocytogenes gene was detected.
A new electrochemical DNA biosensor was fabricated by using a dendritic gold nanoparticles and electrochemical reduced graphene (GR) composite modified carbon ionic liquid electrode (CILE) as the platform. Ionic liquid 1-butylpyridinium hexafluorophosphate was used as the binder for the preparation of CILE and GR film was further decorated on the CILE surface by electrochemical reduction. Then the dendritic nanogold was electrodeposited on the surface of GR/CILE to get a modified electrode as Au/GR/CILE, which was further used for the formation of mercaptoacetic acid self-assembling film. The amino modified ssDNA probe sequence was covalently linked with mercaptoacetic acid to get the ssDNA modified electrode for the further hybridization. Methylene blue (MB) was used as the electrochemical indicator for monitoring the hybridization reaction after hybridized with the target ssDNA. Under the optimal conditions the specific Listeria monocytogenes hly ssDNA sequences could be detected by measuring the differential pulse voltammetric responses of the accumulated MB molecules on dsDNA molecules. The linear concentration range was achieved from 1.0×10−12 to 1.0×10−6mol/L with the detection limit as 2.9×10−13mol/L (3σ). This electrochemical DNA sensor exhibited excellent selectivity with the good discrimination ability of one-base and three-base mismatched ssDNA sequences. The polymerase chain reaction product of L. monocytogenes hly gene that extracted from deteriorated fish was successfully detected, which indicated that this electrochemical DNA sensor could be further used for the detection of specific ssDNA sequence in real biological samples.
ObjectiveThis study aimed to understand the epidemic characteristics of Diarrheagenic Escherichia coli （DEC） in domestic meat products.MethodsThe molecular characteristics of 86 strains of DEC were ...analyzed by whole genome sequencing technology， and the dominant pathological types， STs， and serotypes were identified. The phylogenetic relationship between DEC strains derived from meat products in China was determined through whole genome single nucleotide polymorphism.ResultsThe results showed that the pathological types of DEC in meat products were mainly EAEC. Eighty-six DEC strains were divided into eight virulence genotypes， including 48 ST types （including six new ST types）， and 55 O：H serotypes. ST11 and CC10 were the predominant ST and clonal complex， respectively. O157， O15， and O6 were the predominant serogroups. DEC strains exhibited high genetic heterogeneity， the same pathological type had low homology， and they were in different evolutionary branches.ConclusionThere is no correspondence between DE
To observe the effect of dexmedetomidine (DEX) on the expression of tight junction protein ZO-1 in kidney tissues of rats with acute kidney injury (AKI) induced by sepsis.
Sixty healthy male ...Sprague-Dawley rats were selected and divided into four groups: sham operation group (Sham group), DEX + Sham group, cecal ligation and puncture (CLP) group and DEX + CLP group according to a random number table, with 15 rats in each group. Each group was then divided into 3 subgroups at 6, 12, and 24 hours after the operation, with 5 rats in each subgroup. Modified CLP was used to establish a sepsis model. In Sham group and DEX + Sham group, only laparotomy and abdominal closure were performed. Each group was given pretreatment 1 hour before modeling. DEX + Sham group and DEX + CLP group were pumped into DEX at a rate of 5 μg×kg
×h
through the caudal vein; Sham group and CLP group were pumped with the equal amount of normal saline through the caudal vein. Rats in each group were sacrificed at 6, 12, and 24 hours after op
Compressed sensing (CS) provides an innovative framework for signal sampling, which enables accurate recovery of the sparse or compressible signal from a small set of linear measurements far fewer ...than the Nyquist rate in traditional signal processing. In compressed sensing, random modulation plays a key role, which can spread out the signal information more or less evenly across all locations. There are many modulation techniques, such as amplitude modulation, frequency modulation, phase modulation, spectrum modulation, and so on. Among these modulation techniques, phase modulation is vital due to the efficiency and convenience of modulation. In this paper, we review both the theoretical and application of compressed sensing and several compressed imaging systems using random phase modulation. First, we review the fundamentals of compressed sensing, dividing it into three parts: sparse representation, incoherent measurement, and nonlinear reconstruction algorithm. We then show how phase modulation can be applied to compressed sensing and compressed imaging, where the presentation can be divided into six main parts, corresponding to different aspects of phase modulation applied in compressed sensing or compressed imaging: (1) Fundamentals of compressed sensing. (2) Principles of phase modulation. (3) Single-shot compressed imaging with spatial-domain single random phase mask (CI-SSRPM). (4) Single-shot compressed imaging with a random convolution using a double random phase mask (CI-DRPM). (5) Single-shot compressed imaging with Fourier-domain single random phase mask (CI-FSRPM). (6) Single-shot compressed imaging with double random phase encoding (CI-DRPE).
: A total of 48 Listeria monocytogenes isolates of different import food products from 8 provinces between 2005 and 2008 were characterized. The serotype and virulence were confirmed for each strain ...and molecular subtyping were analyzed by multilocus sequence typing (MLST). Twenty five strains were assigned to serotype 1/2a, and 11 isolates to serotype 1/2b, serotype 4b were found in 7 isolate, and the remaining 5 strains were grouped into serotypes 1/2c, 4a, and 4e. Molecular subtyping schemes found thirty two sequence types (STs) among these isolates and the majority of L. monocytogenes strains belonged to lineage II (56%), followed by lineage I (38%), lineage III (6%). Two molecular subtype clusters, cluster A included all isolates of lineage II, while cluster B contained the isolates of lineages I and lineages III. Two L. monocytogenes strains were not grouped in either of the two clusters. Fifty three isolates were as virulent as L. monocytogenes reference strain EGD in mouse virulence assay, while the isolates 22213 and 22265 had low pathogenicity. These results provide the first molecular insight into the L. monocytogenes strains isolated from import food products of 8 provinces in China and indicate the potential risk to cause human disease if intake by contaminated foods. MLST could be used as a routine subtyping method of L. monocytogenes isolates. In China, inspection and quarantine strategies of imported foods should be strengthened.
Practical Application: There is a potential risk of listeriosis in China and routine subtyping of L. monocytogenes isolates is important. It is necessary for food hygiene management to strengthen the supervision of imported foods.
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