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Accurate server traffic prediction can help enterprises formulate network resource allocation strategies in advance and reduce the probability of network congestion. Traditional prediction models ignore the unique data characteristics of server traffic that can be used to optimize the prediction model, so they often cannot meet the long-term and high-precision prediction required by server traffic prediction. To solve this problem, this paper establishes a hybrid model ARIMA-LSTM-CF, which combines the advantages of linear and nonlinear models, as well as the periodic fluctuation characteristics of server traffic data obtained from banks. In addition, this paper also uses the optimized K-means clustering method to extract the traffic data of workdays and non workdays. The results show that the new hybrid model performs better than the single ARIMA and LSTM models in predicting the long-term trend of server traffic. RMSE (root mean square error) and MAE (mean absolute error) are reduced by 50%. R2 score index reached 0.64. The results show that the model can effectively extract the data characteristics of server traffic data, and the model has accurate and stable long-term prediction ability.

To study the weakening mechanism of the shear characteristics of water-bearing rock joints, four types of artificial saw-tooth joints (including tooth inclination angles of 0°, 15°, 30° and 45°) were prepared in sandstone with four moisture content (0%, 1.55%, 3.1% and 4.65%). This work adopted the non-destructive water intrusion, X-ray diffraction (XRD), acoustic emission (AE) and direct shear tests to mainly investigate the water and inclination angle-induced changes in shear mechanical properties, failure modes and AE characteristics of sandstone rock joints. The results show that the sandstone specimens contain quartz (91.04%), kaolinite, illite and montmorillonite, among which the content of quartz decrease while that of kaolinite and illite increase under the action of water, except that montmorillonite is a little controversial. The shear failure modes of the tested rock joints are divided into climbing, climbing-gnawing combined and gnawing. The inclination angle, followed by normal stress, has the greatest effect on the shear failure modes, and the moisture content has the least effect by comparison. The cohesion and internal friction angle have a positive linear relationship with the inclination angle and a negative linear relationship with the moisture content. According to the test results and Mohr–Coulomb model, a shear strength calculation model of rock joints considering the effect of inclination angle and moisture content is established. The intensity of the AE signal released during specimen failure increases with increasing inclination angle and decreases with moisture content.

The typical sandstone of the Shendong mining area, China, was considered as the research object in order to determine the mechanical properties and fracture evolution characteristics under true triaxial stress and different moisture contents by X-ray diffraction, true triaxial mechanical test, and CT scanning. The results show that the main mineral components of the sandstone are quartz, plagioclase, potassium feldspar, siderite, and clay minerals (kaolinite, illite, and chlorite), with clay minerals accounting for 25.7%. When σ2 > σ3, after sandstone failure, compressive deformation occurs in the e2 direction, while expansion deformation occurs in the e3 direction. A larger σ3 corresponds to a higher moisture content and a greater ductility of sandstone. σ3 influences the sandstone failure mode more significantly, compared with σ2 and moisture content. For a constant moisture content, the sandstone’s compressive strength and the Young’s modulus increase with increase in σ3. On the contrary, as σ2 increases, the compressive strength and the Young’s modulus first increase and then decrease for all moisture contents. Additionally, when the stress state is kept the same, as the moisture content increases, the compressive strength and the Young’s modulus of the sandstone decrease. Similarly, for the same moisture content, with increase in σ2, the smaller the number of fractures after sandstone failure and the more regular the fracture distribution. Moreover, under the same stress conditions, dry sandstone has the least regular fracture development after failure, followed by saturated sandstone, while the sandstone with natural moisture content has the most regular fracture development after failure.

The impact of pharmacogenetics on predicting survival in gastroenteric cancer remains unclear. We tested 322 consecutive patients treated with capecitabine-based chemotherapy for CDA and MTHFR polymorphisms. Patients who carried the CDA 79 A>C (rs2072671) CC genotype showed significantly shorter progression-free survival (PFS) comparing with A-allele (P = 0.008). A significant better PFS was found in the patients with 451 A>G (rs532545) G-allele (P = 0.002) and 92 C>T (rs602950) T-allele (P = 0.002). In addition, a shorter PFS was also observed in patients with MTHFR 1298 A>C (rs1801131) CC genotype than the patients with AC or AA genotype after capecitabine-based chemotherapy (P = 0.002). Furthermore, the colon, female, or elder (> 65 years old) patients with MTHFR 1298 A>C CC genotype had poorer PFS than A-allele. Moreover, CDA 451 A>G was independent predictors of chemotherapy-induced toxicity in colon patients. Multivariate Cox regression analysis demonstrated that the CDA 79 A>C CC, 451 A>G AA, 92 C>T CC, and MTHFR 1298 A>C CC were predictive of shorter PFS in gastroenteric cancer patients. The results reminded us those gastroenteric cancer patients with CDA 79 A>C CC, 451 A>G AA, 92 C>T CC, or MTHFR 1298 A>C CC genotype are not likely to benefit from the therapy of capecitabine-based chemotherapy.

Although diffusion-weighted imaging (DWI) is reported to be accurate in detecting bowel inflammation in Crohn’s disease (CD), its ability to assess bowel fibrosis remains unclear. This study assessed the role of DWI in the characterization of bowel fibrosis using surgical histopathology as the reference standard. Abdominal DWI was performed before elective surgery in 30 consecutive patients with CD. The apparent diffusion coefficients (ADCs) in pathologic bowel walls were calculated. Region-by-region correlations between DWI and the surgical specimens were performed to determine the histologic degrees of bowel fibrosis and inflammation. ADCs correlated negatively with bowel inflammation (r = − 0.499, p

Dispersal ability is important for the introduction, establishment, and spread of alien plant species. Therefore, determination of the geographical distribution of the dispersal ability of such species, and the relationship between dispersal ability and socio-climatic factors are essential to elucidate the invasion strategies of the alien plant species. Analytic hierarchy process and inventory, risk rank, and dispersal mode data available on Chinese alien plant species were used to determine their dispersal ability, the geographical distribution thereof, and the relationship between socio-climatic factors and dispersal ability. High-risk alien plant species had a higher natural dispersal ability (or several natural dispersal modes) but a lower anthropogenic dispersal ability (or few anthropogenic dispersal modes) than low-risk alien plant species. The geographical distribution of the dispersal ability of the alien plant species showed an inverse relationship with species density. Alien plant species with low dispersal ability (i.e., with fewer dispersal modes and distribution in the southeast) showed a tendency to adapt to environments with mild climates, while those with high dispersal ability (i.e., with more disposal nodes and distribution in the northwest) showed a tendency to adapt to harsh environments. It is essential for land managers and policy makers to understand the geographical distribution of the dispersal ability of alien plant species and their socio-climatic control factors to formulate strategies to control the natural and anthropogenic dispersal of such plants.

Studying the effects of the micro- and meso-scale characteristics of coal-bearing sandstone on its mechanical properties can provide basic data and accumulated experience for the development of technology for the in situ testing of the strength of rock masses. In this paper, the micro- and meso-structures, mineral composition, and elemental contents of 16 kinds of sandstone from three coal mines were studied through X-ray diffraction and polarizing microscope analysis. The stress–strain evolutional characteristics of different sandstone samples were obtained through uniaxial compression, tension, and shear tests under acoustic emission monitoring, and the effect of various micro- and meso-characteristics on the mechanical properties and failure characteristics of the sandstones was investigated. The results show that the strength, elastic modulus, cohesion, and friction coefficient all increase with increasing quartz content and degree of particle contact, and decrease with increasing plagioclase and clay mineral content, especially kaolinite content. The failure mode of sandstone samples is mainly shear failure during uniaxial compression, the larger the particles and the lower the quartz content, the higher the RA value generated near the peak, indicating that more tensile failure occurs. Furthermore, the strength damage model and damage constitutive model are established by acoustic emission measurement data. These results could provide useful reference for the development of intelligent systems for the in situ testing of the mechanical properties of coal and rock masses.

High stress is a common technical problem in many coal mines, and coal rock mass fracturing is an effective means to transfer stress. In this paper, the RFPA numerical simulation method is applied to investigate the stress transfer law under the various influence factors. The results show that coal rock mass with cracks produces a “saddle-shaped” stress profile that may be divided into three characteristic zones: a pressure relief zone, a pressure boost zone, and a primary rock stress zone. Shear slip deformation occurs along cracks and cracks are squeezed, forming an elliptical low-stress region around the cracks and a torsion plane in the displacement field. Increased mining-induced stress causes cracks to extend continuously into the bulk, which transfers the high stress at the original crack tip continuously to the new crack tip. This stress transfer phenomenon is enhanced monotonically with increasing crack length and decreasing angle between crack direction and minimum principal stress, thereby weakening the mechanical properties of the crack surface and increasing the number of crack groups. An analysis shows that, in each crack group, cracks oriented at small angles with respect to the minimum principal stress more strongly affect stress transfer, and the pressure relief area is a polygonal area defined by the crack tips. As crack spacing increases, the stress exhibits a low-pressure, high-pressure, low-pressure wave-shape distribution. Finally, with increasing burial depth, the crack pressure relief range becomes small.

In this paper, a non-orthogonal multiple access (NOMA)-based mobile edge computing (MEC) system is proposed, where paired users (the mth user and the nth user) offload tasks to the MEC server under imperfect channel state information (ipCSI) condition. To evaluate the effect on performance under ipCSI condition in NOMA-MEC system, this study derives new exact and asymptotic expressions of the offloading outage probability for two users under ipCSI and perfect channel state information (pCSI) conditions. On the basis of the theoretical derivation, the diversity orders of the nth user under ipCSI and pCSI conditions are zero and n, respectively, while those for the distant user are all zeros. In addition, we also investigate the system throughput and energy efficiency of NOMA-MEC in delay-limited transmission. Numerical results show that (1) the offloading outage behaviors of NOMA-MEC are better than those of time division multiple address (TDMA), (2) the offloading outage performance of paired users under ipCSI is worse than that under pCSI, and (3) the NOMA-MEC system achieves higher throughput and energy efficiency than does the TDMA-MEC system.

The seepage-control design and evaluation of underground water conservancy projects need to consider the effects of water and original fissures on rock mechanical properties and fissure evolution laws. In this paper, uniaxial compression test was conducted on siltstone samples containing prefabricated fissures with different moisture contents to investigate the effects of fissure angle, ligament angle, and moisture contents on the mechanical properties and crack propagation. The results show that the peak stress, elastic modulus, and peak strain of rock are positively correlated with fissure angle and negatively correlated with the ligament angle. With increasing moisture content, the effects of fissure angle and ligament angle on rock mechanical properties gradually decrease, and the peak stress and elastic modulus are negatively linearly correlated with moisture content. The acoustic emission (AE) and photographic monitoring techniques were adopted to analyze the dynamic evolution laws of micro-crack propagation, and seven types of crack initiation and seven kinds of crack coalescence modes were summarized. The failure characteristics and crack coalescence of rock are controlled by fissure angle and ligament angle, and water content has an impact on the whole crack evolution process. This study provides a significant understanding of the instability and failure of underground rock engineering.

We investigate herein the scale effect and anisotropy of jointed rock mass (JRM) from the perspective of acoustic emission (AE) characteristics and estimate the size of the representative element volume (REV). First, we propose an AE calculation based on the discrete element method (DEM) and use the statistical results of joint planes to generate a discrete fracture network. Next, we calibrate the micro-parameters of the rock matrix and the joint plane based on physical experiment and the single plane of weakness theory, respectively. Finally, we use the proposed model to numerically simulate the AE characteristics of a JRM and estimate the size of the REV. The use of different model sizes and layer orientations shows that the AE event magnitude follows a power-law distribution. The frequency of AE events with different magnitudes follows a normal distribution, and a negative exponential relationship is found between the frequency of AE events and the number of cracks associated with each AE event. When the model size exceeds 10 × 10 m, the parameters of AE events (accumulated frequency, magnitude, frequency of AE events associated with only one crack, frequency of AE events associated with over ten cracks, and maximum crack number associated with each AE event) remain essentially constant. This means that the size of the REV is 10 × 10 m. The proposed model should also prove useful for further research into the fracture mechanism of JRM.

Bedding planes are common in shale and significantly affect its mechanical behavior. In this paper, the main focus is investigating the effects of layer orientation on the mechanical behavior of shale under different confining pressures through physical experiments and numerical simulations. First, confining pressure tests were performed to investigate the parameter differences of specimens with vertical bedding planes (SVBPs) and specimens with horizontal bedding planes (SHBPs). Second, the statistical results of the length and spacing of bedding planes were employed to construct the simulation model. Third, the microparameters of the proposed model were confirmed with the results obtained from physical experiments, in which four key factors including deviatoric stress versus axial strain curve, peak strength, Young’s modulus and failure mode were all used to calibrate the feasibility and reliability of the numerical simulation. Finally, a systematic simulation was conducted to investigate the effects of layer orientation on the mechanical behavior of shale. The results show that the mechanical parameters (deviatoric stress vs. axial strain curve, peak strength, Young’s modulus, cohesion and internal friction angle) are greatly affected by layer orientation. Tensile cracking of the rock matrix is dominant in specimens with both vertical and horizontal bedding planes. The crack initiation threshold (CIT) of SVBPs is smaller than that of SHBPs, but the crack damage threshold (CDT) is similar. The percentages of CIT and CDT are nearly unchanged under different confining pressures in both types of specimens. The conformity between the simulation results and physical experiment results suggests that the research method proposed in this study can advance the understanding of rock mass mechanical behavior.

A series of calcium copper titanate (CaCu3Ti4O12, CCTO) samples are prepared by a citric acid sol–gel method and the effect of sintering conditions on microstructure, dielectric and nonlinear electrical properties are investigated in detail. Systematical characterizations by both X-ray diffraction and Raman spectra identify the component phases of sintered products, verifying the formation of single phased CCTO if suitable sintering temperature and durations are selected. Well crystallized grains with the size of several microns are attained for the samples sintered at 1020 °C for 5 h, will make a contribution to giant dielectric behavior, evidenced by the highest value of dielectric constant (e′ > 2.5 × 104) in the frequency range of 102 to 5 × 105 Hz. Dielectric spectroscopy measurements show similar dielectric dispersion for all the samples, which can be well interpreted by the interface polarization from grain boundaries and the bulk effect. Meanwhile, nonlinear electrical behaviors are observed for all the samples, attributing to the Schottky-like electrostatic barriers at the grain boundaries.

Determination of the physical properties of shale is receiving more attention as the numbers of shale gas exploration projects are initiated, and as hydraulic fracturing becomes an integral exploitation method. In particular, anisotropy caused by the bedding structure of shale needs specific attention. In this paper, an anisotropic mineral brittleness-based model (AMBBM) is proposed that makes use of the discrete element method (DEM) to study shale properties, such as anisotropy of non-penetrating bedding planes and separating brittle and non-brittle minerals. Micro-parameters of the AMBBM are calibrated using uniaxial compressive strength tests and by studying the parameter gradient of smooth joints (SJ), such that the strength of SJ mainly affects the failure load in Brazilian tests (FLBT). It is found that the ratio of cohesion to tensile strength of SJ mainly affects the number of cracks formed, which further leads to different failure modes. Normal stiffness and shear stiffness of SJ exerts different effects on FLBT and stiffness in the model. However, the percentage of cracks of various minerals is less affected. The degree of anisotropy is affected by the angle range of parallel bond replaced by bedding plane. Based on the results, a new validation method for AMBBM is proposed, given that the numerical results show good agreement with experimental results, such as FLBT, splitting modulus, and failure mode. The model can thus be used to study seepage properties of shale gas exploitation and hydraulic fracturing by DEM.

Studying the mechanical properties of and crack propagation in coal after water intrusion is necessary to tackle a number of geological engineering problems such as those associated with underground water storage in collieries and support for underground roadways in coal mines. To study the mechanical properties and crack development, 12 coal samples with moisture contents of 0, 2.37, 3.78 and 5.29 % were prepared for acoustic emission tests under uniaxial compression. Over about 6 days, the coal samples absorbed moisture from a humidifier in three different phases. In this period, uniaxial tests show that the peak stress, elastic modulus, strain softening modulus and post-peak modulus decreased with rising moisture content in the samples while the peak strain increased. It was further found that, by analysing the relationship between the stiffness and stress and the accumulated acoustic emission counts, all the phases of crack development can be evaluated. This is useful for studying the effect of water intrusion on crack propagation and for calculating the mechanical properties of the coal such as the elastic modulus. This investigation also quantifies the percentage of the stress thresholds for crack closure, crack initiation, and crack damage that constitutes the peak stress. These stress thresholds do not change with moisture content. Our results are of great significance for water storage in coal mines, for determination of pillar dimensions in coal mines, and for expanding the knowledge base of the mechanical properties of coal and the characteristics of crack propagation.

Co-doped ZnO nanocluster-assembled thin films fabricated by nanocluster-beam deposition have been annealed at 400 and 700 °C. The influence of annealing temperature on the structural, optical, and magnetic properties has been characterized by various diagnostic techniques. It can be found that the crystalline nature and structure were significantly enhanced after the annealing of the as-grown films. When increasing the temperature, the shoulder of the absorbance spectra turned steeper and the intensity of curves become weaker in the range of 210 to 350 nm. A relatively strong UV emission band was detected at around 379 nm. The saturation magnetization of the film annealed at 700 °C was higher than the as-grown one, but it was lower than the films annealed at 400 °C, which may be caused by the decrease in oxygen vacancy with rising the annealing temperature.

We report the fabrication of Cu/Nb-sheathed FeSe0.5Te0.5 superconducting wires by an ex situ powder-in-tube method. After swaging and drawing, the as-drawn wires were heat-treated at different heat conditions. Subsequently, characterizations and transport critical current measurements were performed on the heat-treated FeSe0.5Te0.5 wires. Also, the results of the as-drawn wire are presented for comparison. The FeSe0.5Te0.5 cores reacted with the Nb sheaths when heat-treated at a high temperature or at a low temperature for a long time. Furthermore, according to our results, the highest transport critical current density (J c) at 0.5 and 0.75 T is about 1.6 × 10 4 and 1.5 × 10 3 A/cm 2, respectively.

Background Evaluate the possibility of CT enterography (CTE) score system as a predictor in assessing active ulcerative colitis (UC) severity. Methods Forty-six patients with active UC with CTE and colonoscopy were enrolled. Based on modified Mayo score, patients were divided into three groups: mild (n = 10), moderate (n = 17) and severe (n = 19). A cumulative CTE score was calculated in each patient and its correlation with modified Mayo score was analyzed. The optimal cutoff values of CTE score were determined by receiver operating characteristic (ROC) curves analysis. Results Significant between-group differences were observed in CTE spectrums of mucosal bubbles, mural stratification, loss of haustration, enlarged mesenteric lymph nodes and engorged mesenteric vessels (P

Numerical investigation was performed to examine the effect of rear barrier pillar on stress distribution around a longwall face. Salamon theoretical formula was used to calculate the parameters of the caving zone, which was later assigned to double yield constitutive model in FLAC3D. Numerical results demonstrate that high stress concentration zone exists above the region where the second open-off cut intersects with the rear barrier pillar due to stress transfer and plastic zone expansion. It is also found that the maximum vertical stresses with varied distance to the seam floor are all within the projective plane of the rear barrier pillar and their positions concentrate on the barrier pillar adjacent to the connection corner of the second open-off cut. In addition, position of the maximum vertical stresses abruptly transfer from the connection corner adjacent to former panel to that adjacent to current panel along the panel direction.

As a pioneer, Co-doped ZnO nanocluster-assembled thin films were fabricated by a nanocluster-beam deposition system and the influence of the flow rate of helium gas on the properties of the films was also investigated. Transmission electron microscopy indicated that Co-doped ZnO nanoclusters maintained a wurtzite structure as that of bulk materials. Also, it is found that the average size of ZnO nanoclusters decreased with the increased flow rate of helium gas. Two photoluminescence (PL) bands at 378 and 510 nm were observed. The Co-doped ZnO nanocluster-assembled thin films exhibited ferromagnetic property at room temperature. As the flow rate of helium gas increased, the corresponding saturation magnetization of the nanocluster-assembled thin films decreased from 11 to 6 μemu.

MicroRNAs (miRNAs) are endogenous small (19-24 nt long) noncoding RNAs that regulate gene expression in a sequence specific manner. An increasing association between miRNA and cancer has been recently reported. Lung cancer is globally responsible for 1.4 million deaths annually and is the leading cause of cancer-related deaths in both women and men. In this study, we investigated the miR-21 expression in non-small cell lung cancer (NSCLC) to evaluate their value in prognosis of this tumor. Here, we assess miR-21 expression in NSCLC and its clinical significance including survival analysis. The expression of miR-21 in matched normal and tumor tissues of NSCLC was evaluated using a quantitative real-time RT-PCR. A Kaplan-Meier survival curve was generated following a logrank test. It was observed that miR-21 expression was up-regulated in NSCLC tissues compared with noncancerous lung tissues (mean ± SD: 6.7 ± 2.3 vs. 3.7 ± 1.5, P

Generation, propagation, and coalescence of the shear and tensile cracks in the gob-side filling wall are significantly affected by the location of the fracture of the critical rock block. The Universal Discrete Element Code software was used to investigate crack evolution characteristics in a gob-side filling wall and the parameter calibration process for various strata and the filling wall was clearly illustrated. The cracks in both the filling wall and the coal wall propagate inward in a V-shape pattern with dominant shear cracks generated initially. As the distance between the fracture and the filling wall decreases, the number of cracks in the filling wall decreases, and the stability of the filling wall gradually improves; thus, by splitting the roof rock at the optimal location, the filling wall can be maintained in a stable state. Additionally, we conducted a sensitivity analysis that demonstrated that the higher the coal seam strength, the fewer cracks occur in both the filling wall and the coal wall, and the less failure they experience. With the main roof fracturing into a cantilever structure, the higher the immediate roof strength, the fewer cracks are in the filling wall. With the critical rock block fracturing above the roadway, an optimal strength of the immediate roof can be found that will stabilize the filling wall. This study presents a theoretical investigation into stabilization of the filling wall, demonstrating the significance of pre-splitting the roof rock at a desirable location.

Glutathione S-transferases (GSTs) are phase II enzymes that facilitate the detoxification of xenobiotics and play important roles in antioxidant defense. We investigated the expression patterns of seven Venerupis philippinarum GSTs (VpGSTs) and four Mytilus galloprovincialis GSTs (MgGSTs) following exposure to BDE-47. Differential expressions of the seven VpGSTs and four Mg GSTs transcripts were observed, with differences between the hepatopancreas and gills. Among these GSTs, the sigma classes (VpGSTS1, VpGSTS2, VpGSTS3, MgGST1, and MgGST3) were highly expressed in response to BDE-47 exposure, demonstrating their potential as molecular biomarkers for environmental biomonitoring studies. We obtained the three-dimensional crystal structures of VpGSTs and MgGSTs by homologous modeling. A model to elucidate the binding interactions between the ligands and receptors was defined by molecular docking. Hydrophobic and π were the most often observed interactions between BDE-47 and the GSTs.

We carried out uniaxial compressive experiments on coal specimens with different moisture contents to gain a better understanding of the water-induced weakening characteristics of coal. The effects of moisture content on the strength and deformation characteristics of the specimens were analyzed. The results of the uniaxial compressive experiment demonstrate that the full stress–strain curve presents plastic deformation characteristics with the increase of the moisture content in the coal specimens. A positive linear relation between the peak strain and moisture content and a negative one between the compressive strength and moisture content were observed. The results also show that the elastic modulus and the moisture content satisfy a negative exponential function. Taking the obtained relation as boundary conditions and applying the statistical damage theory and strain equivalence hypothesis, we derived a statistical constitutive damage model for coal which can reflect the effects of the moisture content.

Species richness and abundance are two important species diversity variables that have attracted par- ticular attention because of their significance in determining present and future species composition conditions. This paper aims to explain the qualitative and quantitative relationships between species diversity pattern and grain size (i.e. size of the sampling unit), and species diversity pattern and sampling area, and to analyze species diversity variability on active sand dunes in the Horqin Sandy Land, northeastern Inner Mongolia, China. A 50 m×50 m sampling plot was selected on the windward slope, where the dominant species was annual herb Agriophyllum squarrosum. Species composition and abundance at five grain sizes were recorded, and the species-area curves were produced for thirteen grain sizes. The range of values for species abundance tended to increase with in- creasing grain size in the study area, whereas, generally, species richness did not follow this rule because of poor species richness on the windward slope of active sand dunes. However, the homogeneity of species richness in- creased significantly. With the increase in sampling area, species abundance increased linearly, but richness in- creased logarithmically. Furthermore, variograms showed that species diversity on the windward slope of active sand dunes was weakly anisotropic and the distribution pattern was random, according to the Moran Coefficient. The results also showed that species richness was low, with a random distribution pattern. This conflicts with the results of previous studies that showed spatial aggregation in lower richness in a sampling area within a community and inferred that the physical processes play a more important role in species diversity than distribution pattern on active sand dunes. Further research into different diversity patterns and mechanisms between active sand dunes and interdune lowlands should be conducted to better understand biodiversity conservation in sand dune fields.

A comprehensive analytical method for nearly 1000 semi-volatile organic compounds (SVOC) in sediments has been developed using an automated identification and quantification system with a GC-MS database. The results of recovery tests using model compounds, which comprise of 119 non-polar to polar compounds, showed that the method can quantitatively analyze most SVOC, except for very polar substances. Analytical results of a standard reference material were close to certified concentrations. The detection limits of the method were 4 μg/kg when measuring by TIM and 0.4 μg/kg by SIM. The method was applied to actual sediments in rivers in Ho Chi Minh City, Vietnam. A large number of substances, including persistent organic pollutants, which seem to be discharged from domestic sources, were found at relatively high concentrations. From these results, it is confirmed that the developed method is a useful way to obtain a holistic picture of pollution by SVOC, and is a good tool for rapid screening of chemical pollution in sediments.

Particle flow code (PFC2D) software was adopted to investigate the anchorage behaviour and the characteristics of crack initiation, propagation and coalescence of reinforced specimens containing a single fissure (RSCSF). The microscopic parameters of the specimens in the numerical simulation were first validated by experimental outcomes of intact specimens, while the microscopic parameters of the rock bolts were validated based on the results of the RSCSF tests. Then, the mechanical parameters as well as the failure modes in the physical experiments were compared with those derived by the numerical simulation; the results showed good agreement between the simulated macroscopic mechanical properties and failure modes and those obtained in the laboratory experiments. The peak strength, number of cracks and the failure mode varied considerably as the anchorage angle α and fissure angle β increased. Three types of stress–strain curves, types I to III, were obtained from the RSCSF. Shear cracks were observed for all three categories of curves, but the tensile cracks were dominant. The number of cracks and the rate of bond failures decreased as the curve changed from type II to type I to type III. RSCSF failure can be classified into three failure modes: (1) tip crack propagation mode, (2) midpoint crack propagation mode and (3) rock bolt crack propagation mode. These failure modes are primarily differentiated by relations between α and β, and the ratio UCSS/UCSI between the uniaxial compressive strength (UCS, σ max) of the RSCSF (UCSS) and the uniaxial compressive strength of the intact specimen (UCSI).

The effects of various salinities and desalination on seed germination of six annual glycophytes (Artemisia sieversiana, A. scoparia, Chloris virgata, Eragrostis pilosa, Chenopodium acuminatum and Chenopodium glaucum) were studied in Horqin Sandy Land, Inner Mongolia, China. NaCl solutions of five concentrations (0 mM, as the control, and 50, 100, 200 and 300 mM) were used for saline stress and desalination treatments. Increasing salinity significantly reduced germination percentages of A. sieversiana, A. scoparia, Ch.virgata and Ch. acuminatum, but had no effect on the germination percentages of E. pilosa. Lower salinity levels (50 mM) significantly increased germination percentage of Ch. glaucum. High salinity might be a precondition for germination after desalination for five of the six species, excepting E. pilosa at NaCl concentration of 300 mM in comparison with non-primed seeds. Higher salinity (>200 mM) led to some specific ion toxicity and reduced seed viability of A. sieversiana. No specific ion toxicity but an osmotic effect limited the germination of other five species was observed The final germination percentages (salinity stress and desalination) of the six species showed three variations in comparison with the controls, namely, indiscrimination, stimulation, and reduction. Germination responses to salinity and desalination suggested that the six species were separated into three categories. Three species (A. sieversiana, Ch. virgata and Ch. acuminatum) showed similar germination responses to salinity with those of halophyte, but also showed a lower tolerance limit than most halophytes, although this was not always the case. A. scoparia and Ch. glaucum exhibited some ‘salt stimulation’ in seed germination percentages after desalination, whereas E. pilosa did not show any obvious response to salinity. Therefore, salinity usually induces dormancy of seeds with strong germination capacity in fresh water, but has few, or even positive, effects on seeds with strong innate dormancy.

We assessed the transportation tendency of dioxins and predict locations at high risk for dioxin pollution. A new parameter, the compartment distribution coefficient DC, was created to account for the tendency of dioxins to preferentially accumulate in particular compartments. It was obtained by a model using levels of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in four countries: Japan, the United States, the United Kingdom, and Australia. The comparison with the temporal and spatial variation of DC indicated whether the location release or long-range transportation caused the changes. This study showed that PCDD/Fs have the greatest tendency to remain in soil among studied media. A higher DC value in Australia may indicate that this location is a potential future reservoir source of dioxins.

Two receptor models, positive matrix factorization (PMF) and factor analysis with non-negative constraints (FA-NNC), were applied for source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments of the Daliao River, China. The source profiles and source contributions derived from the two receptor models were comparable. For PMF, PAHs mainly came from coal combustion (43.3%), followed by biomass burning (24.3%), traffic emissions (16.7%) and coke oven (15.7%). As for FA-NNC, coal combustion (50.4%) was dominant, followed by biomass burning (21.9%), traffic emission (15.7%) and coke oven (12.0%). The source apportionment results are consistent with the results from the specific PAH diagnostic ratios and emission inventory analysis. In addition, the source apportionment results are consistent with the structure of energy material usage in Liaoning Province of China.

Bioconcentration factors (BCFs) are of great importance for ecological risk assessment of organic chemicals. In this study, a quantitative structure-activity relationship (QSAR) model for fish BCFs of 8 groups of compounds was developed employing partial least squares (PLS) regression, based on linear solvation energy relationship (LSER) theory and theoretical molecular structural descriptors. The guidelines for development and validation of QSAR models proposed by the Organization for Economic Co-operation and Development (OECD) were followed. The model results show that the main factors governing logBCF are Connolly molecular area (CMA), average molecular polarizability (α) and molecular weight (M W). Thus molecular size plays a critical role in affecting the bioconcentration of organic pollutants in fish. For the established model, the multiple correlation coefficient square (R Y 2) = 0.868, the root mean square error (RMSE) = 0.553 log units, and the leave-many-out cross-validated Q CUM 2 = 0.860, indicating its good goodness-of-fit and robustness. The model predictivity was evaluated by external validation, with the external explained variance (Q EXT 2) = 0.755 and RMSE = 0.647 log units. Moreover, the applicability domain of the developed model was assessed and visualized by the Williams plot. The developed QSAR model can be used to predict fish logBCF for organic chemicals within the application domain.

The human heart is a complex system that reveals many clues about its condition in its electrocardiogram (ECG) signal, and ECG supervising is the most important and efficient way of preventing heart attacks. ECG analysis and recognition are both important and tempting topics in modern medical research. The purpose of this paper is to develop an algorithm which investigates kernel method, locally linear embedding (LLE), principal component analysis (PCA), and support vector machine(SVM) algorithms for dimensionality reduction, features extraction, and classification for recognizing and classifying the given ECG signals. In order to do so, a nonlinear dimensionality reduction kernel method based LLE is proposed to reduce the high dimensions of the variational ECG signals, and the principal characteristics of the signals are extracted from the original database by means of the PCA, each signal representing a single and complete heart beat. SVM method is applied to classify the ECG data into several categories of heart diseases. Experimental results obtained demonstrated that the performance of the proposed method was similar and sometimes better when compared to other ECG recognition techniques, thus indicating a viable and accurate technique.

Annual plants are the main vegetation in arid and semi-arid desert regions. Because of their unique traits, they are the optimal experimental subjects for ecological studies. In this article, we summarize annual plants’ seed germination strategies, seedling adaptability mechanism to environments, seed dispersal, and soil seed banks. We also discuss the biotic and abiotic factors affecting the composition and dynamics of annual plant populations and communities. Because annual plants have important ecological functions in desert vegetation systems, this study on annual plants will be of great benefit to the conservation and restoration of desert ecosystems, the rational utilization of resources, and the sustainable development of desert regions.

Background Klotho is a discovered aging suppressor gene, and its overexpression in mice extends the life span of the animal. Recently, Klotho is also identified as a tumor suppressor gene in variety of tumors; however, the potential role and the antitumor mechanism remain unclarified in liver cancers. Methods RT-PCR and western blotting analysis were used to detect the expression of Klotho, β-catenin, C-myc, and Cyclin D1. MTT assay was used to detect the survival rates of HepG2 and SMMC-7721 cells. Colony formation assay was used to test the proliferation ability in Klotho transfected cells. FACS was used to detect the cell apoptosis rate in different groups. Results The results showed that lower expression of Klotho were found in liver cancer cell lines than the immortalized liver cell L02. Also, MTT assay results found that overexpression or recombinant Klotho administration suppressed the proliferation of liver cancer cells HepG2 and SMMC-7721. Moreover, the colony formation assay results showed that the number of colonies was significantly lower in the cells with transfection with pCMV-Klotho than the controls. Thus, functional analysis demonstrated that Klotho expression inhibited the proliferation of liver cancer cells and Klotho worked as an important antitumor gene in tumor progression. Next, the mechanism was partly clarified that Klotho expression induced cell apoptosis in HepG2 and SMMC-7721 cells, and this phenomenon was mainly involved in the Wnt/β-catenin signaling pathway. The western blotting analysis revealed that overexpression or recombinant administration of Klotho obviously decreased the expression levels of β-catenin, C-myc, and Cyclin D1 in HepG2 cells. Most importantly, the antitumor mechanism for Klotho due to that overexpression of Klotho not only decreased the endogenous β-catenin levels but also inhibited the nuclear translocation of β-catenin to delay the cell cycle progression. Conclusions Klotho was a tumor suppressor gene, and overexpression of Klotho suppressed the proliferation of liver cancer cells partly due to negative regulation of Wnt/β-catenin signaling pathway. So, Klotho might be used as a potential target, and the study will contribute to treatment for therapy of liver cancer patients.

We consider some classes of 2π-periodic functions defined by a class of operators having certain oscillation properties, which include the classical Sobolev class and a class of analytic functions which can not be represented as a convolution class as its special cases. Let $$\lfloor{x}\rfloor$$ be the largest integer not bigger than x. We prove that on these classes of functions the rectangular formula $$Q^*_N(f) = \frac{2\pi}{N}\sum_{j=0}^{N-1} f\left(\frac{2\pi j}{N}\right)$$ is optimal among all quadrature formulae of the form $$Q_{2N}(f) = \sum_{i=1}^{n}\sum_{j=0}^{\nu_{i}-1}a_{ij}f^{(j)}(t_{i}),$$ where the nodes 0 ≤ t1

Structure-activity relationship (SAR) and quantitative structure-activity relationship (QSAR), collectively referred to as (Q)SARs, play an important role in ecological risk assessment (ERA) of organic chemicals. (Q)SARs can fill the data gap for physical-chemical, environmental behavioral and ecotoxicological parameters of organic compounds; they can decrease experimental expenses and reduce the extent of experimental testing (especially animal testing); they can also be used to assess the uncertainty of the experimental data. With the development for several decades, (Q)SARs in environmental sciences show three features: application orientation, multidisciplinary integration, and intelligence. Progress of (Q)SAR technology for ERA of toxic organic compounds, including endpoint selection and mathematic methods for establishing simple, transparent, easily interpretable and portable (Q)SAR models, is reviewed. The recent development on defining application domains and diagnosing outliers is summarized. Model characterization with respect to goodness-of-fit, stability and predictive power is specially presented. The purpose of the review is to promote the development of (Q)SARs orientated to ERA of organic chemicals.