In vitro platelet adhesion on polymeric surfaces with varying fluxes of continuous nitric oxide release

Nitric oxide (NO) is released by endothelial cells that line the inner walls of healthy blood vessels at fluxes ranging from 0.5 × 10 −10 to 4.0 × 10 −10 mol cm −2 min −1 , and this continuous NO release contributes to the extraordinary thromboresistance of the intact endothelium. To improve the biocompatibility of blood-contacting devices, a biomimetic approach to release/generate NO at polymer/blood interfaces has been pursued recently (with NO donors or NO generating catalysts doped within polymeric coatings) and this concept has been shown to be effective in preventing platelet adhesion/activation via several in vivo animal studies. However, there are no reports to date describing any quantitative in vitro assay to evaluate the blood compatibilities of such NO release/generating polymers with controlled NO fluxes. Such a methodology is desired to provide a preliminary assessment of any new NO-releasing material, in terms of the effectiveness of given NO fluxes and NO donor amounts on platelet activity before the more complex and costly in vivo testing is carried out. In this article, we report the use of a lactate dehydrogenase assay to study in vitro platelet adhesion on such NO-releasing polymer surfaces with varying NO fluxes. Reduced platelet adhesion was found to correlate with increasing NO fluxes. The highest NO flux tested, 7.05 (±0.25) × 10 −10 mol cm −2 min −1 , effectively reduced platelet adhesion to nearly 20% of its original level (from 14.0 (±2.1) × 10 5 cells cm −2 to 2.96 (±0.18) × 10 5 cells cm −2 ) compared to the control polymer coating without NO release capability. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56095/1/31105_ftp.pd

Cripto-1 overexpression is involved in the tumorigenesis of nasopharyngeal carcinoma

<p>Abstract</p> <p>Background</p> <p>Human Cripto-1, a member of the EGF-CFC family, is indispensable for early embryonic development. Cripto-1 plays an important oncogenic role during tumorigenesis and is overexpressed in a wide range of epithelial carcinomas, yet little is known about Cripto-1 in nasopharyngeal carcinoma (NPC). The aim of this study was to analyze the roles of Cripto-1 in the progression and clinical characteristics in NPC clinical samples and cell lines.</p> <p>Methods</p> <p>The expression of Cripto-1 at mRNA level was detected by the reverse transcription-polymerase chain reaction (RT-PCR) and real time RT-PCR, and western blot was used to examine the protein expression. Cripto-1 expression and its clinical characteristics were investigated by performing immunohistochemical analysis on a total of 37 NPC clinical tissue samples. Lentiviral vectors were constructed to get an efficient expression of anti-Cripto-1 siRNA in CNE-2 and C666-1 cells, with invalid RNAi sequence as control. After the inhibition of the endogenous Cripto-1, the growth, cell cycle and invasion of cells were detected by MTT, FACS and Boyden chamber assay respectively. Moreover, <it>in vivo</it>, the proliferation of the tumor cells was evaluated in xenotransplant nude mice model with whole-body visualizing instrument.</p> <p>Results</p> <p>The results of real-time RT-PCR and western blot showed that the expression level of Cripto-1 was markedly higher in NPC cell lines than that in the immortalized nasopharyngeal epithelial cell at both mRNA and protein levels. RT-PCR of 17 NPC tissues showed a high expression rate in 76.5% (13/17) cases. In an immunohistochemical study, Cripto-1 was found to express in 54.1% (20/37) cases of NPC. In addition, Cripto-1 overexpression was significantly associated with N classification (<it>p </it>= 0.034), distant metastasis (<it>p </it>= 0.036), and clinical stage (<it>p = </it>0.007). Inhibition of endogenous Cripto-1 by lentivirus-mediated RNAi silencing technique suppressed NPC cell growth and invasion <it>in vitro</it>. <it>In vivo</it>, the average weight (<it>p </it>= 0.026) and volume (<it>p </it>= 0.044) of tumor in CNE-2/GFP⁺/Cripto-1^-xenotransplant mice group were significantly lower than those in the control group. The Ki67 index was obviously lower in Cripto-1 RNAi treated tumors (<it>p </it>< 0.01).</p> <p>Conclusion</p> <p>Data of this study suggest that Cripto-1 overexpression is connected with the tumorigenesis and progression of NPC, lentivector-mediated RNAi might be feasible for the inhibition of the growth and invasion of NPC.</p

Analysis of internal crack healing mechanism under rolling deformation

A new experimental method, called the \u27hole filling method\u27, is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing mechanism. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic deformation, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic deformation followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from the matrix to the crack surface, and also by the nucleation and growth of ferrite grain on the crack surface. The diffusion mechanism is used to explain the source of material needed for crack healing. The recrystallisation mechanism is used to explain grain nucleation and growth, accompanied by atomic migration to the crack surface

Fully distributed consensus for high-order strict-feedback nonlinear multiagent systems with switched topologies

summary:This paper studies the distributed consensus problem of high-order strict-feedback nonlinear multiagent systems. By employing the adaptive backstepping technique and switched system theory, a novel protocol is proposed for MASs with switched topologies. Global information such as the number of agents and communication topology is not used. In addition, the communication topology between agents can be switched between possible topologies at any time. Based on the Lyapunov function method, the proposed adaptive protocol guarantees the complete consensus of multiagent systems without restricting the dwell time of the switched signal. Finally, two numerical examples are provided to illustrate the effectiveness and advantages of the given protocol

Static and dynamic crushing of novel porous crochet-sintered metal and its filled composite tube

© 2018 Elsevier Ltd A novel porous crochet-sintered metal (PCSM) is fabricated by rolling a crocheted porous cloth and subsequent vacuum sintering using a continual single super-fine soft 304 rope twisted by 49 fibers as raw material. This work investigates the quasi-static and dynamic axial crushing response of PCSMs and their filled composite tubes. The pore structures of PCSMs are formed by inter-crocheted and multiple inter-locked rope skeletons and metallurgical bonds. The PCSMs have almost no initial impact effects with a high crushing force efficiency. Filling the PCSMs changes the deformation model of 6063 tube, improves the static crashworthiness parameters of 6063 tube by 8–25% with almost no increasing initial impact effect, and doesn't always play a positive role in dynamic absorption. Porosity has obvious influence on the quasi-static and dynamic behavior and crashworthiness of PCSMs and their filled composite tube, and the effect of porosity on dynamic crashworthiness of composite tube is greater than that on quasi-static crashworthiness of composite tube. The PCSMs and their composite tubes show great potential for application in energy absorbers. The method of filling PCSM into bare tube is possible to improve the energy absorption ability of thin-walled tube with almost no increase in the initial peak force

Case report: A case study on the treatment using icaritin soft capsules in combination with lenvatinib achieving impressive PR and stage reduction in unresectable locally progressive pancreatic cancer and a literature review

Background: Pancreatic cancer is one of the most deadly malignancies in the world. It is characterized by rapid progression and a very poor prognosis. The five-year survival rate of pancreatic cancer in China is only 7.2%, which is the lowest among all cancers and the use of combined paclitaxel albumin, capecitabine, and digital has been the clinical standard treatment for advanced pancreatic cancer since 1997. Also, the application of multidrug combinations is often limited by the toxicity of chemotherapy. Therefore, there is an urgent need for a more appropriate and less toxic treatment modality for pancreatic cancer.Case presentation: The patient was a 79-year-old woman, admitted to the hospital with a diagnosis of unresectable locally advanced pancreatic cancer (T3N0M0, stage IIA), with its imaging showing overgrowth of SMV involvement and unresectable reconstruction of the posterior vein after evaluation. As the patient refused chemotherapy, lenvatinib (8 mg/time, qd) and icaritin soft capsules (three tablets/time, bid) were recommended according to our past experience and a few clinical research cases. The tumor lesion was greatly reduced by 57.5% after the treatment, and the extent of vascular involvement also decreased. The aforementioned medication resulted in a significant downstaging of the patient’s tumor.Conclusion: Better results were achieved in the treatment with icaritin soft capsules and lenvatinib in this case. Because of its less toxic effect on the liver and kidney and bone marrow suppression, it was suitable to combine icaritin soft capsules with targeted drugs for treating intermediate and advanced malignancies, which brings hope to patients who cannot or refuse to take chemotherapy

Changing Pattern of Characteristic Components in Black Garlic during Processing Analyzed by Ultra-high Performance Liquid Chromatography-Triple Quadrupole Tandem Mass Spectrometry

An analytical method based on ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-TQ-MS/MS) was established for the simultaneous determination of 10 flavor precursors and 21 free amino acids in black garlic. The method was applied for exploring the changing pattern of characteristic components in black garlic during processing. The results showed that the characteristic components in black garlic changed significantly during processing at 75 ℃ and 85% relative humidity. Among them, γ-aminobutyric acid, S-allyl-L-cysteine, isoalliin, glutamine, methiin, alliin, tryptophan, and γ-L-glutamyl-S-allyl-L-cysteine changed most obviously, and were identified as the chemical markers of changes in small molecular metabolites during the processing of black garlic. The established method has high sensitivity and accuracy, and can meet the detection requirements

Optimization of degradable temporary plugging material and experimental study on stability of temporary plugging layer

Temporary plugging technology is an important drilling technique for maintaining wellbore stability and resolving lost circulation problems. The key to its success lies in the use of materials that can form a tight and stable “temporary plugging layer” with certain pressure bearing capacity and a permeability close to zero in the loss channel near the wellbore. Experimental studies have been conducted to develop adhesion formulations for optimal temporary plugging materials, as the matching relationship between particle size and fracture width is critical [(0.5−1)/1]. By measuring the permeability of the temporary plugging layer under varying confining pressure with a soap foam flowmeter, researchers have been able to evaluate the effectiveness, degradation, and dosages of temporary plugging agents. It has been shown that a single-particle material, such as a walnut shell, has a smaller permeability than a hyperfine CaCO3 coated temporary plug layer. The latter, however, is less capable of bearing pressure. By combining different materials, such as walnut shells and hyperfine CaCO3 particles, the researchers were able to create a temporary plug layer that had the lowest permeability and did not change much at variable confining pressures. Its pressure-bearing capacity is strong and the temporary plug works well. Experiments have shown that a ratio of 2:1–3:1 of hyperfine CaCO3 and walnut shell particles work well for plugging a fracture system with particles of size 2–3 times the fracture width. It developed an evaluation method for temporary plugging agents, studied their plugging capability and degradation performance for reservoir conversion, and evaluated degradation performance after successful temporary plugging. The temporary plugging rate of the temporary plugging agent increased from 98.10% to 99.81%, and the maximum temporary plugging pressure is 50.39 MPa, which can be completely reduced at 150°C for 4 h, meeting the technical requirements of “dense temporary plugging, two-way pressure bearing” to some extent

The novel proteins Rng8 and Rng9 regulate the myosin-V Myo51 during fission yeast cytokinesis.

The myosin-V family of molecular motors is known to be under sophisticated regulation, but our knowledge of the roles and regulation of myosin-Vs in cytokinesis is limited. Here, we report that the myosin-V Myo51 affects contractile ring assembly and stability during fission yeast cytokinesis, and is regulated by two novel coiled-coil proteins, Rng8 and Rng9. Both rng8Δ and rng9Δ cells display similar defects as myo51Δ in cytokinesis. Rng8 and Rng9 are required for Myo51's localizations to cytoplasmic puncta, actin cables, and the contractile ring. Myo51 puncta contain multiple Myo51 molecules and walk continuously on actin filaments in rng8(+) cells, whereas Myo51 forms speckles containing only one dimer and does not move efficiently on actin tracks in rng8Δ. Consistently, Myo51 transports artificial cargos efficiently in vivo, and this activity is regulated by Rng8. Purified Rng8 and Rng9 form stable higher-order complexes. Collectively, we propose that Rng8 and Rng9 form oligomers and cluster multiple Myo51 dimers to regulate Myo51 localization and functions