4,226 research outputs found
COMPARING THE DIFFERENCE BETWEEN FRONT-LEG AND BACK-LEG ROUND-HOUSE KICKS ATIACKING MOVEMENT ABILITIES IIN TAEKWONDO
The purpose of this study is to compare front-leg and back-leg movement abilities in Taekwondo athletes with a weight level of less than 68 kg. Six male subjects (age: 19.8±1, height: 175.6±3.9, weight: 62.5±4.8) conducted back-leg attacking movements and front-leg attacking movements with their dominant leg. The back-leg attacking movements include back leg round-house kick and strike back round house kick. The front-leg attacking movements include front leg round-house kick and slide round-house kick. From statistics obtained, the kicking of relative force, compound acceleration, and tangential acceleration are better for back-leg attacking movements. However, front-leg attacking movements are better in tangential velocity. The range of waist a rotation and the flexibility of the hip joint are important to roundhouse kick techniques to the kinetic chain
Influence of concave groove on transmission of blasting vibration wave
With the extensive application of blasting techniques, the prediction and hazard control of explosion-induced vibration is an important issue which cannot be ignored in blasting engineering. A numerical approach is presented to study the explosion-induced pressure load on the surface of C-4 explosives in a semi-infinite space, in order to explore the effectiveness of concave grooves in ground vibration wave barrier. Numerical simulations are carried out by using a widely applied explicit dynamic nonlinear finite element software LS-DYNA and adopted the Arbitrary Lagrangian-Eulerian method for numerical analysis to simulate the propagation of blast waves. The analysis shows that the concave grooves have a significant effect on attenuating the propagation of detonation waves. The vibration control is related to the width and depth of the groove, and the impact of the depth is greater than that of the width. This study can be used as a reference in hazard control of explosion-induced vibration
Characterization of the role of VEGFA isoforms in cell migration and metastasis using engineered microenvironments
Background: Mortality in cancer patients is predominantly caused by metastasis. Understanding mechanisms that lead to cancer cells gaining metastatic potential may lead to novel therapies that could prevent metastasis and improve overall survival. Increased cellular plasticity in adopting different modes of migration has been identified as an important factor in efficient metastasis. Although it is predominantly known as a major regulator of angiogenesis, Vascular Endothelial Growth Factor A (VEGFA) has also been shown to regulate cell migration and thus metastatic potential. VEGFA encodes for several isoforms through alternate mRNA splicing which exerts differences in signalling and biological activity. Using fibrosarcomas derived from mouse embryonic fibroblasts genetically engineered to express a single VEGFA isoform, previous research I contributed to showed there was an increased number of metastases to the lung from cells expressing only VEGFA120 (fs120 cells) compared to cells expressing VEGFA188 (fs188 cells) suggesting fs120 cells may have better metastatic potential. These studies also showed metastasis to the lung was selectively inhibited by anti-VEGFA antibodies in mice with fs120 tumours and this acted in part through inhibition of migration (English et al., 2017). During my MSc studies, I extended these studies of migration and found fs120 cells could migrate more efficiently in a custom non-adherent migration chamber than fs188 cells and this was inhibited by anti-VEGFA antibodies. As these suggested VEGFA120-expressing cells have greater plasticity in modes of cell migration and can adapt to more varied environments than VEGFA188-expressing cells, we hypothesised increased metastatic potential is VEGFA isoform-dependent and linked to an ability to adopt different migration modes in response to different microenvironments. However, as there are differences in embryonic development between mice expressing VEGFA120 and VEGFA188, and the mice were not isogenic, these findings needed to be confirmed in a new model with identical developmental and genetic backgrounds.
Objectives: To create new fibrosarcoma cell lines expressing single VEGFA isoforms to characterise differences in cell migration in comparison with embryonic-derived fibrosarcomas and to develop novel engineered microenvironments to test the plasticity of cell migration.
Methodology: Fibrosarcomas expressing only VEGFA120 or VEGFA188 were derived from Vegfa knockout (KO) adult mouse fibroblasts by stably introducing a VEGFA expression cassette using a transposon. Cellular functions, including cell proliferation, and the expression of cell migration-related proteins were characterized by MTT assay and western blotting in selected clones. PCL electrospinning of fibre scaffolds was used to mimic fibrillar collagen structures seen after imaging fs120 and fs188 mouse tumour sections by second-harmonic generation microscopy to generate a novel environment to characterise plasticity in migration. Cell migration capacity of adult- versus embryonic-derived fibrosarcomas expressing a single VEGFA isoform was characterised using in vitro platforms by single-cell live imaging. Altered expression of cell migration-related proteins across cell lines on treatment with inhibitors targeting VEGFA signal transduction (VEGFA by antibody B20.4.1.1, VEGFR1 by antibody MF-1 and VEGFR/PDGFR/FGFR by receptor tyrosine kinase inhibitor pazopanib) were characterized by Western blotting.
Results: The expression of single VEGFA isoforms in new, fibrosarcoma cell lines, derived from Vegfa KO fibroblasts, were successfully generated to express VEGFA at comparable levels to the fs120 and fs188 cells as determined by ELISA and QRT-PCR. There was no difference in the expression of VEGFR1 across any of the cell lines, but the upregulated expression of NRP1 was seen in fs188 cells compared to other cell lines. Increased phosphorylated Akt was observed in all fibrosarcoma cells generated from embryonic fibroblasts and in adult Vegfa KO cells expressing VEGFA188. Moreover, fs120 cells expressed a higher level of SOX2 than all other cell lines. The migration capacity of cells on 2D surfaces coated with fibronectin or collagen and on 3D-aligned fibre scaffolds was similar between VEGFA120 and VEGFA188 expressing cells, and independent of their origin. Interestingly, suppressed migration capacity was detected only in cells expressing VEGFA120 on treatment with the anti-VEGFA antibody, B20.4.1.1, indicating VEGFA isoform selective response independent of cell origin. The anti-VEGFR1 antibody MF-1 did not inhibit migration. Increased phosphorylation of VEGFR1 in VEGFA120-expressing fibrosarcoma cells was observed on treatment with B20.4.1.1 and pazopanib, but not MF-1. However, increases in phosphorylated Akt were repressed only by pazopanib treatment.
Conclusions: Fibrosarcoma cells expressing different VEGFA derived from different origins share similar characteristics, suggesting VEGFA isoform-independent changes between models. Downregulated migration capacity in fibrosarcoma cells expressing VEGFA120 in response to anti-VEGFA antibody, B20.4.1.1, was also independent of cell origin. Fibrosarcoma cells expressing VEGFA120 and VEGFA188 have comparable capacity in 2D and fibrillar migration. The differential expression of a VEGFA single isoform may not contribute to the modulation of plasticity in cell migration modes. However, in previous results from the MSc thesis, the motility of fs188 cells was abolished in the confined non-adherent chamber compared with fs120 cells. This discrepancy suggests that the varying expression of VEGFA isoforms in fibrosarcoma cells may play roles in regulating the adaptation of amoeboid mode that is integrin-independent, as opposed to migrating on 1D fibrillar structures. Nonetheless, confirming this idea would necessitate evaluating the migratory abilities of new cell lines within the confined non-adherent chamber. Upregulation of p-VEGFR1 was observed in VEGFA120-expressing cells treated with anti-VEGFA antibody and pazopanib, whereas downregulation of p-Akt was observed only with the pazopanib treatment. These suggest another receptor also interacting with VEGFA120 participates in regulating cell migration. In conclusion, the expression of VEGFA120 may potentially increase cell plasticity through another receptor, besides VEGFR, interacting with VEGFA. This signalling pathway is affected explicitly by the anti-VEGFA antibody and pazopanib. These outcomes open up a novel target for further treatment to prevent metastasis
Synthesis of thioesters through copper-catalyzed coupling of aldehydeswith thiols in water
Copper-catalyzed C–S bond formation between aldehydes and thiols in the presence of TBHP as an oxidant is described. Functional groups including chloro, trifluoromethyl, bromo, iodo, nitrile, ester and thiophene are all tolerated by the reaction conditions employed. This reaction is performed in water without the use of a surfactant. Both aryl and alkyl aldehydes couple suitably with aryl- and alkyl thiols, affording the corresponding thioesters in moderate to good yields
Feasibility of Combined UASB-MBR System in Treating PTA Wastewater and Polyimide Membrane for Biogas Purification
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Analysis of blast-induced ground vibration under surface explosion
The blasting operation is vital in the construction of tunnels and channels or in mining when encountering hard geological environments to facilitate the progress of a project. The level and range of damage due to the blast are affected by the energy of shock waves generated after explosion. The control of seismic damage is a major issue in blasting engineering and cannot be neglected. The stratum layer or buildings on the earth’s surface can be damaged when blasting-induced vibration strength exceeds the allowed range. In order to reduce the degree of damage, the patterns of blasting vibration must be studied and controlled. Therefore, the propagation characteristics of shock waves on the earth’s surface are important factors to be studied before the planning and designing of a project. This paper adopted a mutual verification method between the blasting experiment and numerical analysis results for verifying the reliability of numerical simulation based on experimental data. The numerical analysis method analyzed the dynamic mechanical behavior of blasting vibration using the finite element method. The LS-DYNA program was used to simulate TNT explosive and surface contact blasting in semi-infinite space and in propagation of the resulting seismic waves. The propagation characteristics, represented by temporal and spatial changes of surface acceleration, were investigated. The analysis results showed that post-explosion dynamic characteristics of the earth’s surface simulated by finite element method yielded promising simulation results. In addition, the propagation characteristics of stress waves were observed from the dynamic mechanical behavior of surface acceleration after explosion. That is, the maximum main stress presented a pattern of progressive attenuation with increasing distance from the blasting source. The results are able to provide reference for the protection of engineering structures from blasting vibration damages
Nd-YAG Laser Treatment for Tracheobronchial Obstruction
The Nd-YAG laser has good tissue penetration and coagulation effects thus has become an
important weapon for photoresection of tracheobronchial obstructive lesions since 1980
An On-Line Personalized Promotion Decision Support System for Electronic Commerce
With the development of the Internet and Electronic Commerce (EC), enterprises have overcome the space and time barriers and are now capable of serving customers electronically. However, it is a great challenge to attract and retain the customers over Internet. One approach is to provide the responsive personalized service to satisfy the customer demand and promote sales at the first time. Hence, in this paper, we propose a decision support system which develops best promotion products based on combinations of different marketing strategies, pricing strategies, and customer behaviors evaluated in terms of multiple criteria. Data mining techniques are utilized to help the business discover patterns to develop on-line sales promotion products for each customer for enhancing customer satisfaction and loyalty.
The proposed system consists of four components: (1) establishing marketing strategies, (2) promotion pattern model, (3) personalized promotion products, and (4) on-line transaction model. A simple example is given to illustrate the implementation and application of proposed decision support system
Keyword Join: Realizing Keyword Search in P2P-based Database Systems
In this paper, we present a P2P-based database sharing system that provides information sharing capabilities through keyword-based search techniques. Our system requires neither a global schema nor schema mappings between different databases, and our keyword-based search algorithms are robust in the presence of frequent changes in the content and membership of peers. To facilitate data integration, we introduce keyword join operator to combine partial answers containing different keywords into complete answers. We also present an efficient algorithm that optimize the keyword join operations for partial answer integration. Our experimental study on both real and synthetic datasets demonstrates the effectiveness of our algorithms, and the efficiency of the proposed query processing strategies.Singapore-MIT Alliance (SMA
- …