338 research outputs found

    Investigation of ultra-thin Al₂O₃ film as Cu diffusion barrier on low-k (k=2.5) dielectrics

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    Ultrathin Al(2)O(3) films were deposited by PEALD as Cu diffusion barrier on low-k (k=2.5) material. The thermal stability and electrical properties of the Cu/low k system with Al(2)O(3) layers with different thickness were studied after annealing. The AES, TEM and EDX results revealed that the ultrathin Al(2)O(3) films are thermally stable and have excellent Cu diffusion barrier performance. The electrical measurements of dielectric breakdown and TDDB tests further confirmed that the ultrathin Al(2)O(3) film is a potential Cu diffusion barrier in the Cu/low-k interconnects system

    Docosahexaenoic acid has influence on action potentials and transient outward potassium currents of ventricular myocytes

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    <p>Abstract</p> <p>Background</p> <p>There are many reports about the anti-arrhythmic effects of ω-3 polyunsaturated fatty acids, however, the mechanisms are still not completely delineated. The purpose of this study was to investigate the characteristics of action potentials and transient outward potassium currents (I<sub>to</sub>) of Sprague-Dawley rat ventricular myocytes and the effects of docosahexaenoic acid (DHA) on action potentials and I<sub>to</sub>.</p> <p>Methods</p> <p>The calcium-tolerant rat ventricular myocytes were isolated by enzyme digestion. Action potentials and I<sub>to </sub>of epicardial, mid-cardial and endocardial ventricular myocytes were recorded by whole-cell patch clamp technique.</p> <p>Results</p> <p><b>1.</b> Action potential durations (APDs) were prolonged from epicardial to endocardial ventricular myocytes (<it>P </it>< 0.05). <b>2.</b> I<sub>to </sub>current densities were decreased from epicardial to endocardial ventricular myocytes, which were 59.50 ± 15.99 pA/pF, 29.15 ± 5.53 pA/pF, and 12.29 ± 3.62 pA/pF, respectively at +70 mV test potential (<it>P </it>< 0.05). <b>3.</b> APDs were gradually prolonged with the increase of DHA concentrations from 1 μmol/L to 100 μmol/L, however, APDs changes were not significant as DHA concentrations were in the range of 0 μmol/L to 1 μmol/L. <b>4.</b> I<sub>to </sub>currents were gradually reduced with the increase of DHA concentrations from 1 μmol/L to 100 μmol/L, and its half-inhibited concentration was 5.3 μmol/L. The results showed that there were regional differences in the distribution of action potentials and I<sub>to </sub>in rat epicardial, mid-cardial and endocardial ventricular myocytes. APDs were prolonged and I<sub>to </sub>current densities were gradually reduced with the increase of DHA concentrations.</p> <p>Conclusion</p> <p>The anti-arrhythmia mechanisms of DHA are complex, however, the effects of DHA on action potentials and I<sub>to </sub>may be one of the important causes.</p

    Highly efficient in vitro adventitious shoot regeneration of Adenosma glutinosum (Linn.) Druce using leaf explants

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    Adenosma glutinosum (Linn.) Druce is an important aromatic plant, but no information is available regarding its regeneration, callus induction and proliferation from leaf explants. In this study, an in vitro shoot regeneration procedure was developed for native A. glutinosum using leaf explants. Callus induction and shoots regeneration from leaf explants was evaluated on Murashige and Skoog (MS) media supplemented with combinations of 6-benzylaminopurine (6-BA) and α-naphthaleneacetic acid (NAA). Callus induction in all 16 treatments exceeded 95%, and the highest adventitious shoot number per callus (7.22 shoots per explant) was obtained when leaf explants were cultured on MS medium supplemented with 0.5 mg• L-1 6-BA, 0.1 mg• L-1 NAA, 3% sucrose and 0.72% agar. The highest shoots strengthening were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.3 mg• L-1 NAA, 3% sucrose, 1.0 g• L-1 active carbon and 0.72% agar. The highest total root number (45.2) and root length (43.3 cm) were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.0 mg• L-1 NAA, 3% sucrose, 1.0 g L−1 active carbon and 0.72% agar, while the highest total root surface area (4.1 cm2) and total root volume (114.1 mm3) were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.5 mg• L-1 NAA, 3% sucrose, 1.0 g• L-1 active carbon and 0.72% agar. The efficient plant regeneration system developed here will be helpful for rapid micropropagation and further genetic improvement in A. glutinosum. Keywords: Adenoma glutinous, plant growth regulator, plant regenerationAfrican Journal of Biotechnology Vol. 11(29), pp. 7542-7548, 10 April, 201

    RF-thermal-structural-RF coupled analysis on the travelling wave disk-loaded accelerating structure

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    Travelling wave (TW) disk-loaded accelerating structure is one of the key components in normal conducting (NC) linear accelerators, and has been studied for many years. In the design process, usually after the dimensions of each cell and the two couplers are finalized, the structure is fabricated and tuned, and then the whole structure characteristics can be measured by the vector network analyzer. Before the structure fabrication, the whole structure characteristics are less simulated limited by the available computer capability. In this paper, we described the method to do the RF-thermal-structural-RF coupled analysis on the TW disk-loaded structure with one single PC. In order to validate our method, we first analyzed and compared our RF simulation results on the 3m long BEPCII structure with the corresponding experimental results, which shows very good consistency. Finally, the RF-thermal-structure-RF coupled analysis results on the 1.35m long NSC KIPT linac accelerating structure are presented.Comment: 5 pages, 16 figures, Submitted to the Chinese Physics C (Formerly High Energy Physics and Nuclear Physics

    Retrospective analysis for thirty-nine patients with solitary fibrous tumor of pleura and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Solitary fibrous tumor of the pleura (SFTP) is an uncommon neoplasm arising from mesenchymal cells. The aim of this study is to summarize the experience and the outcome of the surgical treatment for 39 cases of SFTP.</p> <p>Methods</p> <p>From January 2004 to December 2008, 39 patients underwent surgical resection of SFTP in our department. All patients had clinical follow-up by the same team of surgeons. The mean follow-up was 40.3 months.</p> <p>Results</p> <p>A local removal of the neoplasm was accomplished by video-assisted thoracic surgery (VATS) in 9 patients (group A) and by thoracotomy in 30 patients (group B) respectively. Comparing with group B, operations in group A took significantly less operative time, blood loss and spent less time in the intensive care unit and hospital. All specimens were positive for CD34 and Bcl-2. One patient developed recurrence, and the remaining 38 patients are alive and disease free at the end of follow-up.</p> <p>Conclusions</p> <p>Malignant SFTP still had the potential recurrence. VATS represents the more acceptable choice for the selected patients with SFTP.</p

    Lentivirus-mediated RNA interference targeting the H19 gene inhibits cell proliferation and apoptosis in human choriocarcinoma cell line JAR

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    BACKGROUND: H19 is a paternally imprinted gene that has been shown to be highly expressed in the trophoblast tissue. Results from previous studies have initiated a debate as to whether noncoding RNA H19 acts as a tumor suppressor or as a tumor promotor in trophoblast tissue. In the present study, we developed lentiviral vectors expressing H19-specific small interfering RNA (siRNA) to specifically block the expression of H19 in the human choriocarcinoma cell line JAR. Using this approach, we investigated the impact of the H19 gene on the proliferation, invasion and apoptosis of JAR cells. Moreover, we examined the effect of H19 knockdown on the expression of insulin-like growth factor 2 (IGF2), hairy and enhancer of split homologue-1 (HES-1) and dual-specific phosphatase 5 (DUSP5) genes. RESULTS: H19 knockdown inhibited apoptosis and proliferation of JAR cells, but had no significant impact on cell invasion. In addition, H19 knockdown resulted in significant upregulation of HES-1 and DUSP5 expression, but not IGF2 expression in JAR cells. CONCLUSIONS: The finding that H19 downregulation could simultaneously inhibit proliferation and apoptosis of JAR cells highlights a putative dual function for H19 in choriocarcinoma and may explain the debate on whether H19 acts as a tumor suppressor or a tumor promotor in trophoblast tissue. Furthermore, upregulation of HES-1 and DUSP5 may mediate H19 downregulation-induced suppression of proliferation and apoptosis of JAR cells

    Four Simple Biomimetic Mineralization Methods to Improve the Thermostability and Immunogenicity of Virus-like Particles as a Vaccine against Foot-and-Mouth Disease.

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    peer reviewedThe need for a cold chain system during storage and transport substantially increases the cost of vaccines. Virus-like particles (VLPs) are among the best countermeasures against foot and mouth disease virus (FMDV). However, VLPs are composed of pure proteins, and thus, are susceptible to heat. To address this problem, four simple biomimetic mineralization methods with the use of calcium phosphate were developed to improve heat tolerance via biomineralization. The results showed that biomineralization can significantly improve the heat resistance of VLPs. The biomineralized VLPs can be stored at low as 25 °C for eight days, and 37 °C for four days. Animal experiments showed that biomineralization had no effect on the immunogenicity of VLPs or the expression of specific antibodies (Abs) and neutralizing Abs. Even after heat treatment at 37 °C for four days, the biomineralized VLPs remained immunogenic and produced highly specific and neutralizing Abs with a high rate of protection. These results suggest that these biomineralization approaches can promote the thermal stability of VLPs against and significantly reduce dependence on cold storage and delivery systems
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