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Fatigue damage estimation is a key part in a Steel Catenary Riser (SCR) system design. The riser-soil interaction has a significant influence on the fatigue assessment for a SCR system at the Touch-Down Zone (TDZ) because the soil’s vertical stiffness is a critical parameter. The conventional methods developed to calculate the soil’s vertical stiffness, for example, DNV method [10], Bridge method [4] and Audibert method [3], were based on the assumption that at the TDZ area the soil mass being interacted by the pipe is always under intact condition. Recently, Chen et al. published a newly developed method [5, 6], which was based on the laboratory test results carried out by Texas A&M University in the late 1980s and was further verified by recent laboratory displacement-controlled tests by Texas A&M University [2], resulting in softer soil’s vertical stiffness. In order to understand the difference between Chen method and the conventional methods as well as the influence of Chen method on the SCR design, a study was carried out for a given soil condition and three typical sizes of riser pipes and is documented in this paper. In this paper, firstly, various methods used to calculate soil’s vertical stiffness, i.e., DNV method, Bridge method, Audibert method, and Chen method, were briefly introduced. Secondly, a discussion was performed on the model of the conventional methods and the model of Chen method. Thirdly, as an example for a given soil condition, the soil’s vertical stiffness was estimated using these methods respectively for 6″-dia., 12″-dia., and 18″-dia. riser pipes. Finally, the fatigue damages for various riser pipes were computed using the estimated soil’s vertical stiffness and a comparison on the estimated fatigue damages was performed. The study results showed that the soil’s vertical stiffness estimated by Chen method was about one order magnitude weaker than these estimated by the conventional methods. In other words, the soil’s vertical stiffness estimated by the conventional methods was about 5 to 11 times that estimated by Chen method. The pipe’s fatigue life estimated using the soil’s vertical stiffness of Chen method was about 1.5 times (i.e., 50% longer than) that estimated using the soil’s vertical stiffness of the conventional methods. These study results could improve a SCRs designer’s understanding on: 1) the difference between the model of the conventional methods and the model of Chen method, 2) the impact of Chen method on the estimated fatigue life, and 3) that as the model of the conventional methods is a closer representative of the prototype and their results are more conservative, it is recommended to use the conventional methods for SCRs design. Eventually, these will help the designers to select an appropriate method for calculating the soil’s vertical stiffness in the SCRs design.

Suction piles have not been widely used in carbonate-type soils (i.e., muds/silts) because the pile skin frictions in this type of soils are only about 5% of that in normal clayey soils. The holding capacity of a suction pile installed in these types of soils may be affected by its lower friction. Moreover, pile designers have concerns not only on the development of the Reverse End Bearing (REB) but also on how long the REB can sustain. This paper presents the development of a three-Dimensional Finite Element Analysis (3D FEA) model and the analysis results to investigate the behavior of suction pile for different levels of skin frictions. Firstly, the FEA model is used to investigate the development of the Reverse End Bearing (REB) of a suction pile by assigning two different levels of pile external skin frictions, i.e., 5% and 100% (full skin friction). A vertical load is applied at the center of the pile top. Secondly, the FEA model is used to investigate the behavior of a suction pile for a very low level of pile skin friction (i.e., 5% skin friction). An inclined load with various load angles from horizontal is applied at the padeye (i.e., 16m below seabed). Thirdly, the load carrying (failure) mechanism has been checked by examining the total displacement vectors of soil masses around the pile. Fourthly, a sensitivity study is carried out to investigate the capacity of a suction pile for different usage factors of REB. Finally, suction pile design requirements for carbonate-type soils (i.e., low level of pile skin frictions) are recommended.

The crystal structure, phase transformation, and elastic properties of copper oxide (CuO) are determined using first-principles calculations. The calculated results first predict the phase transformation from monoclinic to cubic structure, which occurs at 29.32 GPa, and the high-pressure phase is identified as cubic CuO. With increasing pressure, the variations of the elastic constant Cij, bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio υ, the ratio of the bulk to shear modulus B/G, and normalized primitive cell volume V/V0 are investigated. Our results show that the pressure has a positive effect firstly and then negative effect on the ductility of monoclinic CuO, but results in the opposite of hardness. Moreover, we find that the structural abnormality of monoclinic CuO may be existing at pressures of 15 GPa.

In this work, the structural stability, electronic and optical properties of novel stanene/ZnO heterostructure were investigated by using first-principles calculation. The results show that the lattice constants of Sn/ZnO heterostructure are in good agreement with the previous studies, and the stability of Sn/ZnO with interlayer distance of 3.0 A (h3.0-Sn/ZnO) is better than that of other constructed Sn/ZnO. The band gap of Sn/ZnO can be effectively tuned by interlayer distances, external electric field and strain. Notably, h3.2-Sn/ZnO HTS occurs an indirect-to-direct band gap transition after −1% strain. The absorption coefficient of Sn/ZnO HTS exhibit strongest peak in ultraviolet zone, illustrating that they possess an excellent absorption capability. In general, the calculated results provides a new perspective for the potential application of novel Sn/ZnO in further nanoelectronics.

Over the past few decades, FACTS technology has been developed rapidly. And various FACTS controllers have been widely used in the world. This paper presents the development and status of FACTS technology, and introduces the applications of FACTS controllers, especially the typical domestic applications. The key technologies such as system design, control strategy design, equipment development, etc. are summarized. Then, in view of the demands and challenges of FACTS controllers, combined the trends of innovative technologies, the development trend and application prospect of FACTS technology are forecasted.

First-principles calculations were performed to investigate the electrical and optical properties of $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ with Sn-doped $$\hbox {In}_{2}\hbox {O}_{3}$$ and $$\hbox {InGaZnO}_{4}$$ (IGZO). The band structure, density of states, optical properties including dielectric function, loss function, reflectivity and absorption coefficient are calculated. The calculated total energy shows that the most stable crystal structures are type III for $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ and type II for $$\hbox {InGaZnO}_{4}$$ . The band structure indicates the both $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ and $$\hbox {InGaZnO}_{4}$$ are direct gap semiconductors. The intrinsic band gap of $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ is much narrower than that of $$\hbox {InGaZnO}_{4}$$ , and results in a better electrical conductivity for $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ . The density of states shows the main hybridization occurring between In-4d and O-2p states for $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ while between In-4d In-5p, Zn-4s and O-2p states for $$\hbox {InGaZnO}_{4}$$ near the valence band maximum. The reflectivity index $$R({\omega })$$ shows that the peak value of $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ and $$\hbox {InGaZnO}_{4}$$ appears only in the ultraviolet range, indicating that these two materials have all excellent transparency. In addition, the absorption coefficient $${\alpha }({\omega })$$ of both $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$ and $$\hbox {InGaZnO}_{4}$$ is high in the ultraviolet frequency range, and therefore they show, a high UV absorption rate.

Metastatic and invasive potential is a barrier to the successful treatment of gastric cancer. N-acetylgluco-saminyltransferase V (GnT-V), a key enzyme catalyzing the formation of 1,6 N-acetylglucosamine (GlcNAc), has been demonstrated to display a distinct function in different types of tumors. The aim of this study was to investigate the role of GnT-V in the invasive potential of BGC823 human gastric cancer cells in vitro and the possible underlying mechanism. GnT-V was downregulated in BGC823 cells by oligo-siRNA transfection. Cell proliferation and invasiveness were assessed by CCK-8 assay, Tunel assay, scratch-wound assay as well as transwell assay. The products of GnT-V, β1-6 branching of asparagine-linked oligosaccharides, were determined by L-PHA lectin blot analysis. The expression of EGFRs, E-cadherin/vimentin and MMP-2/MMP-9 was analyzed both at the mRNA and protein levels. The results showed that downregulation of GnT-V decreased proliferation and the metastatic/invasive potential of BGC823 cells. The expression of EGFRs, E-cadherin/vimentin and MMP-9, molecules related to cancer metastasis and invasion in various tumors, were influenced correspondingly. These findings suggest that downregulation of GnT-V inhibited cell metastasis and invasion of BGC823 cells via EGFR signaling-initiated EMT phenotype and MMP-9 expression. These results provide a novel mechanism to explain the role of GnT-V in cell metastasis and invasion.

Objective: To investigate the effects of bone morphogenetic protein-2 (BMP-2) on the proliferation, differentiation and apoptosis of normal human gastric mucosal cells and gastric cancer cells.Methods: Poorly differentiated gastric cancer BGC823 cells, moderately differentiated gastric cancer cells and normal human gastric mucosal epithelial GES-1 cells were independently treated with recombinant human BMP-2 or its inhibitor Noggin. MTT assay was performed to detect the proliferation, flow cytometry done to measure the cell cycle and apoptosis and immunohistochemistry carried out to determine the expression of cyclin-dependent kinase 4 (CDK4).Results: BMP-2 exerted inhibitory effect on the growth of all types of cells and the inhibition become more evident with the increase of BMP-2 dose. After treatment with 200 ng/ml BMP-2, cancer cells arrested in G1 phase and those in S phase reduced. Gastric cancer cells had higher CDK4 expression than GES-1 cells. BMP-2 decreased CDK-4 expression in cancer cells but had no influence in GES-1 cells. Noggin conferred promotive effect on the growth of 3 types of cells. In 2 types of cancer cells, treatment with 2000 ng/ml Noggin significantly increased the proportion of cells in S phase but reduced that in G1 phase. However, Noggin did not affect the cell cycle of GES-1 cells. The CDK4 expression was markedly increased in 2 types of cancer cells but that of GES-1 remained unchanged after treatment with 2000 ng/ml Noggin.Conclusions: BMP-2 may inhibit the proliferation of both normal and malignant gastric epithelial cells, down-regulate CDK4 expression in gastric cancer cells and arrest gastric cancer cells in G1-phase in cell cycle. Through antagonizing BMP-2, Noggin, may accelerate the proliferation of gastric cancer cells. Thus, the abnormality of BMP signaling pathway may play an important role in the pathogenesis of gastric cancer.

Long large-diameter driven piles (i.e., 2.0∼3.0m-diameter piles with a 100m penetration or deeper) have been usually used as Tension Leg Platforms’ (TLP) foundations in normally consolidated clay. In order to optimize a design, TLP designers would like to reduce the pile spacing, resulting in a pile group effect issue for pile geotechnical designers. This paper presents the development of a three-Dimensional Finite Element Analysis (3D FEA) model using Finite Element Code PLAXIS 3D to investigate the pile group effect of the TLP driven piles in normally consolidated clay. Using this model, a series of FEA runs were carried out. Firstly, the FEA model was used to examine the mobilization of axial capacity and the related group effect of a pile group, with various numbers of piles per group and different pile spacing. Secondly, the FEA model was used to investigate the group effects on the lateral capacity of a pile group, with respects of mobilization of lateral capacity, influence of loading direction, influence of pile spacing, and influence of number of piles in one group. These FEA results were also compared with the literature studies. Finally, recommendations on pile group effects for both axial capacity and lateral capacity were provided for TLP driven pile geotechnical designs in normally consolidated clay.Copyright © 2014 by ASME

Trefoil Factor Family (TFF) plays an essential role in the intestinal epithelial restitution, but the relationship between TFF1 and gastric cancer (GC) is still unclear. The present study aimed to determine the role of TFF1 in repairing gastric mucosa and in the pathogenesis of GC. The TFF1 expression in different gastric mucosas was measured with immunohistochemistry. Then, siRNA targeting TFF1 or plasmids expressing TFF1 gene were transfected into BGC823 cells, SGC7901 cells and GES-1 cells. The cell proliferation was detected with MTT assay and apoptosis and cell cycle measured by flow cytometry. From normal gastric mucosa to mucosa with dysplasia and to gastric cancer, the TFF1 expression had a decreasing trend. Down-regulation of TFF1 expression significantly reduced the apoptosis of three cell lines and markedly facilitated their proliferation but had no significant effect on cell cycle. Over-expression of TFF1 could promote apoptosis of three cell lines and inhibit proliferation but had no pronounced effect on cell cycle. TFF1 can inhibit proliferation and induce apoptosis of GC cells in vitro.

Objective: To investigate the effects of bone morphogenetic protein-2 (BMP-2) on the proliferation, differentiation and apoptosis of normal human gastric mucosal cells and gastric cancer cells. Methods: Poorly differentiated gastric cancer BGC823 cells, moderately differentiated gastric cancer cells and normal human gastric mucosal epithelial GES-1 cells were independently treated with recombinant human BMP-2 or its inhibitor Noggin. MTT assay was performed to detect the proliferation, flow cytometry done to measure the cell cycle and apoptosis and immunohistochemistry carried out to determine the expression of cyclin-dependent kinase 4 (CDK4). Results: BMP-2 exerted inhibitory effect on the growth of all types of cells and the inhibition become more evident with the increase of BMP-2 dose. After treatment with 200 ng/ml BMP-2, cancer cells arrested in G1 phase and those in S phase reduced. Gastric cancer cells had higher CDK4 expression than GES-1 cells. BMP-2 decreased CDK-4 expression in cancer cells but had no influence in GES-1 cells. Noggin conferred promotive effect on the growth of 3 types of cells. In 2 types of cancer cells, treatment with 2000 ng/ml Noggin significantly increased the proportion of cells in S phase but reduced that in G1 phase. However, Noggin did not affect the cell cycle of GES-1 cells. The CDK4 expression was markedly increased in 2 types of cancer cells but that of GES-1 remained unchanged after treatment with 2000 ng/ml Noggin. Conclusions: BMP-2 may inhibit the proliferation of both normal and malignant gastric epithelial cells, down-regulate CDK4 expression in gastric cancer cells and arrest gastric cancer cells in G1-phase in cell cycle. Through antagonizing BMP-2, Noggin, may accelerate the proliferation of gastric cancer cells. Thus, the abnormality of BMP signaling pathway may play an important role in the pathogenesis of gastric cancer.

A novel model of fuzzy clustering neural network is discussed, which synthesizes unsupervised fuzzy competitive learning algorithm and self-organized competitive network. Based on this model, an algorithm of abrupt video shot boundary detection is presented which is a two-stage clustering on a linear feature space. The experimental results obtained demonstrate that the algorithm is feasible and efficient.