150 research outputs found

    Stability-Oriented Minimum Switching/Sampling Frequency for Cyber-Physical Systems:Grid-Connected Inverters Under Weak Grid

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    Safety and efficacy of Hypofractionated stereotactic radiosurgery for high-grade Gliomas at first recurrence: a single-center experience.

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    BACKGROUND: The optimal treatment for recurrent high-grade gliomas (rHGGs) remains uncertain. This study aimed to investigate the efficacy and safety of hypofractionated stereotactic radiosurgery (HSRS) as a first-line salvage treatment for in-field recurrence of high-grade gliomas. METHODS: Between January 2016 and October 2019, 70 patients with rHGG who underwent HSRS were retrospectively analysed. The primary endpoint was overall survival (OS), and secondary endpoints included both progression-free survival (PFS) and adverse events, which were assessed according to Common Toxicity Criteria Adverse Events (CTCAE) version 5. The prognostic value of key clinical features (age, performance status, planning target volume, dose, use of bevacizumab) was evaluated. RESULTS: A total of 70 patients were included in the study. Forty patients were male and 30 were female. Forty-nine had an initial diagnosis of glioblastoma (GBM), and the rest (21) were confirmed to be WHO grade 3 gliomas. The median planning target volume (PTV) was 16.68 cm3 (0.81–121.96 cm3 ). The median prescribed dose was 24 Gy (12–30 Gy) in 4 fractions (2–6 fractions). The median baseline of Karnofsky Performance Status (KPS) was 70 (40–90). With a median follow-up of 12.1 months, the median overall survival after salvage treatment was 17.6 months (19.5 and 14.6 months for grade 3 and 4 gliomas, respectively; p = .039). No grade 3 or higher toxicities was recorded. Multivariate analysis showed that concurrent bevacizumab with radiosurgery and KPS \u3e 70 were favourable prognostic factors for grade 4 patients with HGG. CONCLUSIONS: Salvage HSRS showed a favourable outcome and acceptable toxicity for rHGG. A prospective phase II study (NCT04197492) is ongoing to further investigate the value of hypofractionated stereotactic radiosurgery (HSRS) in rHGG

    Cactus pear: a natural product in cancer chemoprevention

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    BACKGROUND: Cancer chemoprevention is a new approach in cancer prevention, in which chemical agents are used to prevent cancer in normal and/or high-risk populations. Although chemoprevention has shown promise in some epithelial cancers, currently available preventive agents are limited and the agents are costly, generally with side effects. Natural products, such as grape seed, green tea, and certain herbs have demonstrated anti-cancer effects. To find a natural product that can be used in chemoprevention of cancer, we tested Arizona cactus fruit solution, the aqueous extracts of cactus pear, for its anti-cancer effects in cultured cells and in an animal model. METHOD: Aqueous extracts of cactus pear were used to treat immortalized ovarian and cervical epithelial cells, as well as ovarian, cervical, and bladder cancer cells. Aqueous extracts of cactus pear were used at six concentrations (0, 0.5, 1, 5, 10 or 25%) to treat cells for 1, 3, or 5 days. Growth inhibition, apoptosis induction, and cell cycle changes were analyzed in the cultured cells; the suppression of tumor growth in nude mice was evaluated and compared with the effect of a synthetic retinoid N-(4-hydroxyphernyl) retinamide (4-HPR), which is currently used as a chemoprevention agent. Immunohistochemistry staining of tissue samples from animal tumors was performed to examine the gene expression. RESULTS: Cells exposed to cactus pear extracts had a significant increase in apoptosis and growth inhibition in both immortalized epithelial cells and cancer cells in a dose- and time-dependent manner. It also affected cell cycle of cancer cells by increasing G1 and decreasing G2 and S phases. Both 4-HPR and cactus pear extracts significantly suppressed tumor growth in nude mice, increased annexin IV expression, and decreased VEGF expression. CONCLUSION: Arizona cactus pear extracts effectively inhibited cell growth in several different immortalized and cancer cell cultures, suppressed tumor growth in nude mice, and modulated expression of tumor-related genes. These effects were comparable with those caused by a synthetic retinoid currently used in chemoprevention trials. The mechanism of the anti-cancer effects of cactus pear extracts needs to be further studied

    SYNTHESIS AND APPLICATIONS OF METAL/SEPIOLITE AND METAL OXIDE/SEPIOLITE NANOCOMPOSITES

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    In the United States, the Amargosa Valley of Nevada has the exclusively exploitable and commercial deposit of sepiolite. However, the current sepiolite products are mainly low-value products. Hence, developing advanced and value-added sepiolite nanocomposites products has a promising future. In this study, the structure and morphology changes of sepiolite samples were investigated under thermal treatment from 200 to 1000ÂşC. The results revealed the dehydration law, structure folding process, and the morphology change of sepiolite. Then the effect of the differently acidic attack on the structural characteristics of sepiolite was also studied. The results showed the effect of HNO3, H2SO4 and HCl attack on the purification, the structure change and functional group change of sepiolite. Then the Cu/sepiolite, Ni/sepiolite, NiO/sepiolite, ZnO/sepiolite, and Cu@ZnO/sepiolite nanocomposites were prepared by a simple sorption-reduction or sorption-oxidation process. (1) For Cu/sepiolite nanocomposites, the reaction conditions, such as Cu concentration, reduction temperature, and reduction time have a significant effect on the size of copper nanoparticles. (2) For Ni/sepiolite nanocomposites, the diverse characterization results revealed that the Ni nanoparticles with a mean diameter of about 12 nm mono dispersedly resided on the surface of the sepiolite fibers. (3) For NiO/sepiolite nanocomposites, the size of the nanoparticles obtained increased with the heating temperature increasing. (4) For ZnO/sepiolite nanocomposites, the ZnO nanoparticles with a mean diameter of about 50 nm preferentially resided on the surface of sepiolite. (5) For Cu@ZnO/sepiolite nanocomposites, the nanoparticles obtained in this study had a core/shell structure, which is made up of a copper core and zinc oxide shell. Finally, the antibacterial applications of these nanocomposites were studied, which showed good antibacterial properties against E. coli and S. aureus

    Relationship between threshold and bifurcations for paradoxical firing responses along with seizure induced by inhibitory stimulation

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    Inhibition-induced enhancement or paradoxical response of firing was related to Hopf bifurcation instead of saddle-node bifurcation on an invariant cycle (SNIC), due to the “negative” threshold and rotated vector fields. In the present letter, by changing multiple parameters to adjust the vector fields, the condition for the paradoxical response and “negative” threshold is extended to SNIC near a codimension-2 bifurcation appearing prior to the Hopf bifurcation, which presents a comprehensive relationship between bifurcations and threshold. Especially, the result for a special current can well explain the enhanced firing along with seizure induced by inhibitory interneuron, implying that SNIC far from the codimension-2 bifurcation of pyramidal neuron is a potential candidate to avoid seizure

    Chaotifying fuzzy hyperbolic model using adaptive inverse optimal control approach

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    In this paper, the problem of chaotifying the continuous-time fuzzy hyperbolic model (FHM) is studied. By tracking the dynamics of a chaotic system, a controller based on inverse optimal control and adaptive parameter tuning methods is designed to chaotify the FHM. Simulation results show that for any initial value the FHM can track a chaotic system asymptotically
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