531 research outputs found

    3-D calibration method and algorithm for freehand image of phased array ultrasonic testing

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    Phased array ultrasonic testing (UT) is an advanced technique applying ultrasound wave vibration theory to detect the flaw in tested materials by imaging. In this research, computer 3-D visualization of the flaw through calibrating the ultrasonic phased array image is proposed. 3-D calibration for ultrasonic phased array image is a procedure to calculate the spatial transformation matrix, spatial relationship between the US image plane and the tracker attached to the UT probe. The calibration method depends on a cross-string phantom and the corresponding algorithm. The phantom with a set of crosses guiding the operator quickly to find the scanning plane. The ten string crosses in the scanning plane provide the coordinates and spatial vectors for the calibration algorithm, thus the calibration algorithm can be realized based on the least-squares fitting method of the homologous points matching. Select the points having different distances and angles with the reference point to calculate the matrix and average them as the final result. The results show that the scanning plane positioning time is no more than 5 s. The precision and the accuracy results are the same as that is obtained through the other published methods in the medical 3-D ultrasound image calibration. The results make the 3-D flaw model reconstruction possible in phased array ultrasonic NDT. It will reduce the difficulties in the flaw recognizing and localization

    A Smac-mimetic sensitizes prostate cancer cells to TRAIL-induced apoptosis via modulating both IAPs and NF-kappaB

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    <p>Abstract</p> <p>Background</p> <p>Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising agent for human cancer therapy, prostate cancer still remains resistant to TRAIL. Both X-linked inhibitor of apoptosis (XIAP) and nuclear factor-kappaB function as key negative regulators of TRAIL signaling. In this study, we evaluated the effect of SH122, a small molecule mimetic of the second mitochondria-derived activator of caspases (Smac), on TRAIL-induced apoptosis in prostate cancer cells.</p> <p>Methods</p> <p>The potential of Smac-mimetics to bind XIAP or cIAP-1 was examined by pull-down assay. Cytotoxicity of TRAIL and/or Smac-mimetics was determined by a standard cell growth assay. Silencing of XIAP or cIAP-1 was achieved by transient transfection of short hairpin RNA. Apoptosis was detected by Annexin V-PI staining followed by flow cytometry and by Western Blot analysis of caspases, PARP and Bid. NF-kappaB activation was determined by subcellular fractionation, real time RT-PCR and reporter assay.</p> <p>Results</p> <p>SH122, but not its inactive analog, binds to XIAP and cIAP-1. SH122 significantly sensitized prostate cancer cells to TRAIL-mediated cell death. Moreover, SH122 enhanced TRAIL-induced apoptosis via both the death receptor and the mitochondrial pathway. Knockdown of both XIAP and cIAP-1 sensitized cellular response to TRAIL. XIAP-knockdown attenuated sensitivity of SH122 to TRAIL-induced cytotoxicity, confirming that XIAP is an important target for IAP-inhibitor-mediated TRAIL sensitization. SH122 also suppressed TRAIL-induced NF-kappaB activation by preventing cytosolic IkappaB-alpha degradation and RelA nuclear translocation, as well as by suppressing NF-kappaB target gene expression.</p> <p>Conclusion</p> <p>These results demonstrate that SH122 sensitizes human prostate cancer cells to TRAIL-induced apoptosis by mimicking Smac and blocking both IAPs and NF-kappaB. Modulating IAPs may represent a promising approach to overcoming TRAIL-resistance in human prostate cancer with constitutively active NF-kappaB signaling.</p

    Natural IAP inhibitor Embelin enhances therapeutic efficacy of ionizing radiation in prostate cancer

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    This is the published version, also available here: http://www.ncbi.nlm.nih.gov/pubmed/21804946.Embelin is an active ingredient of traditional herbal medicine that exhibits anti-tumor effects in human prostate cancer cells. However, therapeutic effect of embelin in combination with conventional radiation therapy is not yet determined. In this study, we evaluate the sensitizing potential of embelin on ionizing radiation (IR) in a human prostate cancer model. In vitro, embelin combined with radiation potently suppressed prostate cancer PC-3 cell proliferation that was associated with S and G2/M arrest in cell cycle. Moreover, the combination treatment promoted caspase-independent apoptosis, as evidenced by the increased apoptotic cell death without caspase-3 activation, but not autophagy. Clonogenic survival assay showed that S-phase arrest was required for embelin-mediated radiosensitization. In vivo, embelin significantly improved tumor response to X-ray radiation in the PC-3 xenograft model. Combination therapy produced enhanced tumor growth delay and prolonged time to progression, with minimal systemic toxicity. Immunohistochemistry studies showed that embelin plus IR significantly inhibited cell proliferation, induced apoptosis, and decreased microvessel density in tumors as compared with either treatment alone, suggesting an enhanced combinatory inhibition on tumor suppression and angiogenesis. Our results demonstrate that embelin significantly facilitates tumor suppression by radiation therapy both in vitro and in vivo in the prostate cancer model. This finding warrants embelin as a novel adjuvant therapeutic candidate for the treatment of hormone-refractory prostate cancer that is resistant to radiation therapy

    Preparation and properties of asphalt binders modified by THFS extracted from direct coal liquefaction residue

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    This paper aims to study the preparation and viscoelastic properties of asphalt binder modified by tetrahydrofuran soluble fraction (THFS) extracted from direct coal liquefaction residue. The modified asphalt binders, which blended with SK-90 (control asphalt binder) and 4%, 6%, 8% and 10% THFS (by weight of SK-90), were fabricated. The preparation process for asphalt binder was optimized in terms of the orthogonal array test strategy and gray correlation analysis results. The properties of asphalt binder were measured by applying Penetration performance grade and Superpave performance grade specifications. In addition, the temperature step and frequency sweep test in Dynamic Shear Rheometer were conducted to predict the rheological behavior, temperature and frequency susceptibility of asphalt binder. The test results suggested the optimal preparation process, such as 150 °C shearing temperature, 45 min shearing time and 4000 rpm shearing rate. Subsequently, the addition of THFS was beneficial in increasing the high-temperature properties but decreased the low-temperature properties and resistance to fatigue. The content analysis of THFS showed the percentage of 4~6% achieved a balance in the high-and-low temperature properties of asphalt binder. The asphalt binder with higher THFS content exhibited higher resistance to rutting and less sensitivity to frequency and temperature

    Natural Proteasome Inhibitor Celastrol Suppresses Androgen-Independent Prostate Cancer Progression by Modulating Apoptotic Proteins and NF-kappaB

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    Celastrol is a natural proteasome inhibitor that exhibits promising anti-tumor effects in human malignancies, especially the androgen-independent prostate cancer (AIPC) with constitutive NF-κB activation. Celastrol induces apoptosis by means of proteasome inhibition and suppresses prostate tumor growth. However, the detailed mechanism of action remains elusive. In the current study, we aim to test the hypothesis that celastrol suppresses AIPC progression via inhibiting the constitutive NF-κB activity as well as modulating the Bcl-2 family proteins.We examined the efficacy of celastrol both in vitro and in vivo, and evaluated the role of NF-κB in celastrol-mediated AIPC regression. We found that celastrol inhibited cell proliferation in all three AIPC cell lines (PC-3, DU145 and CL1), with IC₅₀ in the range of 1-2 µM. Celastrol also suppressed cell migration and invasion. Celastrol significantly induced apoptosis as evidenced by increased sub-G1 population, caspase activation and PARP cleavage. Moreover, celastrol promoted cleavage of the anti-apoptotic protein Mcl-1 and activated the pro-apoptotic protein Noxa. In addition, celastrol rapidly blocked cytosolic IκBα degradation and nuclear translocation of RelA. Likewise, celastrol inhibited the expression of multiple NF-κB target genes that are involved in proliferation, invasion and anti-apoptosis. Celastrol suppressed AIPC tumor progression by inhibiting proliferation, increasing apoptosis and decreasing angiogenesis, in PC-3 xenograft model in nude mouse. Furthermore, increased cellular IκBα and inhibited expression of various NF-κB target genes were observed in tumor tissues.Our data suggest that, via targeting the proteasome, celastrol suppresses proliferation, invasion and angiogenesis by inducing the apoptotic machinery and attenuating constitutive NF-κB activity in AIPC both in vitro and in vivo. Celastrol as an active ingredient of traditional herbal medicine could thus be developed as a new therapeutic agent for hormone-refractory prostate cancer

    The enhancement of electrochemical capacitance of biomass-carbon by pyrolysis of extracted nanofibers

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    Biomass-derived carbons have been extensively researched as electrode material for energy storage and conversion recently. However, most of the previous works convert crude biomass directly into carbon and the electrochemical capacitances for the resultant carbons are quite often underestimated as well as large variations in capacitances exist in literatures due to the complex nature of biomass, which practically hinder their applications. In this work, polysaccharide nanofibers were extracted from an inexpensive natural fungus using a hydrothermal method and were converted to porous carbon nanofibers (CNFs) by potassium hydroxide activation. The porous carbons were assembled into symmetric supercapacitors using both potassium hydroxide and an ionic liquid (IL) as electrolytes. Solid state nuclear magnetic resonance characterization showed that the micropores of the as-prepared carbons are accessible to the IL electrolyte when uncharged and thus high capacitance is expected. It is found in both electrolytes the electrochemical capacitances of CNFs are significantly higher than those of the porous carbon derived directly from the crude fungus. Furthermore, the CNFs delivered an extraordinary energy density of 92.3 Wh kg−1 in the IL electrolyte, making it a promising candidate for electrode materials for supercapacitors.<br/

    Correlation and combining ability analysis of physiological traits and some agronomic traits in maize

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    Combining ability information on the physiological traits in maize (Zea mays L) and the relationship between physi¬ological traits and biomass, grain yield (GY) and yield components (YC) can help maize breeders design experi¬ments for improving inbred lines and/or developing hybrids with improved GY or YC (GYYC). A six-parent diallel experiment (Griffing method 3) was conducted for combining ability and correlation analyses. The objectives of this study were to 1) study the correlation between physiological traits and biomass at seedling stage; 2) study which physiological traits at seedling stage have significant correlation with biomasses at both seedling and later growth stages and GYYCs; 3) evaluate combining ability of the physiological traits that are significantly correlated with either GY or one of the YCs. Results showed plant heights at 20 day, 40 day, and leaf area were highly corre¬lated with both dry weights of shoots and roots. All chlorophyll-related organelles were significantly correlated with only dry weights of shoots. However, dry matter at seedling stage seemed not to be related to dry matter in later growth stages. Five physiological traits (stomatal conductance, transpiration rate, net photosynthetic rate, two quantum yield related traits) at seedling stage were identified to greatly impact dry matter at later growth stages. Results also showed that 13 out of 35 physiological traits studied were significantly correlated with GYYCs. Differ¬ent germplasms for improving GYYCs could be used based on both correlation between the 13 traits and GYYCs and combining ability effects of each line for the 13 selected traits

    Synthesis and biological evaluation of novel bi-gold mitocans in lung cancer cells

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    Mitochondria are promising drug target for cancer treatment. We previously demonstrated that a bi-gold compound BGC2a was more potent than the mono-gold drug auranofin in suppressing cancer cells due to increased gold atom number that led to higher drug accumulation in and thereby inhibition of mitochondria. To exploit the potential of this new strategy, we further designed and synthesized a series of bi-gold mitocans, the compounds targeting mitochondria. The results showed that most of the newly synthesized mitocans exhibited obviously lower IC50 than auranofin, an old drug that is repurposed in clinical trials for cancer treatment. The best mitocan C3P4 was nearly 2-fold more potent than BGC2a in human non-small cell lung cancer A549 cells and mantle cell lymphoma Jeko-1 cells, exhibiting substantial colony formation-suppressing and tumor-suppressing effects in A549 cells xenograft model. C3P4 induced apoptosis in a dose-dependent manner and arrested cell cycle at G0/G1 phase. The mechanistic study showed that C3P4 significantly increased the global reactive oxygen species and mitochondrial superoxide level, and reduced the mitochondrial membrane potential. C3P4 preferentially accumulated in mitochondria as measured by the gold content and substantially inhibited oxygen consumption rate and ATP production. These results further validated our hypothesis that targeting mitochondria would be promising to develop more potent anticancer agents. C3P4 may be further evaluated as a drug candidate for lung cancer treatment
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