1,990 research outputs found
Rotor fault diagnosis based on wavelet packet energy spectrum and adaptive fuzzy weighted support vector machine
In this study, a novel application of a wavelet packet energy-weighted support vector machine (WPE-WSVM) is proposed to perform fault classification of helicopter rotor. Because the helicopter rotor fault signal is weak, it is difficult to extract fault feature. The wavelet package is adopted to decompose the vibration signals on the fuselage into different frequency bands, and to eliminate the noise. And then single signal was reconstructed to extract the energy in each frequency band serving as fault feature vectors. And support vector machine was applied for classifying the failure mode of the helicopter rotor. For classification task support vector machine is used due to its good robustness and generalization performances. But the classification accuracy of standard support vector machine is relative slow when the number of samples of different classes is dramatically different. So a fuzzy weighted support vector machine was proposed, which added weight coefficient to samples of different classes. A comparative analysis of standard support vector machine and proposed fuzzy weighted support vector machine is done. The proposed fuzzy weighted support vector machine improved the classification accuracy of class with fewer samples. The proposed method is sufficiently accurate, fast, and robust, which makes it suitable for use in helicopter rotor fault diagnosis applications
Efficacy of Er:YAG laser on periodontitis as an adjunctive nonâsurgical treatment: A splitâmouth randomized controlled study
Aim
To evaluate the adjunctive efficacy of Er:YAG laser use with mechanical scaling and root planing (SRP ) for nonâsurgical treatment of periodontitis.
Materials and Methods
In a randomized, singleâblinded, controlled trial, 27 patients were recruited. Using a splitâmouth design, two quadrants were randomly allocated into either a test group or a control group. The test quadrants received Er:YAG laser (ERL ; 100 mJ /pulse; 15 Hz to hard tissue and 50 mJ /pulse; 30 Hz to soft tissue) plus SRP treatment, while the control quadrants received SRP only. We evaluated periodontal indexes, including probing depth (PD ), clinical attachment level (CAL ), bleeding index (BI ), and plaque index (PLI ) at baseline, 3 months, and 6 months.
Results
The PD and CAL means in the ERL + SRP group were significantly lower than those in the SRP group at 3âmonth followâup (PD : 2.98 ± 0.38 mm vs. 3.09 ± 0.35 mm; CAL : 4.51 ± 0.69 mm vs. 4.72 ± 0.67 mm) and 6âmonth followâup (PD : 2.91 ± 0.31 mm vs. 3.02 ± 0.30 mm; CAL : 4.52 ± 0.65 mm vs. 4.72 ± 0.66 mm; p = 0.03 for both PD and CAL ). There were no significant differences in BI and PLI between two groups.
Conclusions
The Er:YAG laser treatment combined with conventional SRP significantly improved PD and CAL compared to SRP therapy alone; however, these differences were very small and, as a result, the adjunctive effect of Er:YAG laser is likely to be minimal clinically important
Comparison of endostatin(endostar)and avastin's inhibition effect on mice choroidal neovascularization
AIM:To observe the inhibition effect of endostatin(endostar)on mice choroidal neovascularization model(CNV)and compare with the Avastin.<p>METHODS: Using 532nm laser photocoagulation to establish a mouse model of CNV. We observed the formation of CNV by histopathological examination after 2wk later. Forty successful models of mice were randomly divided into control group(group 1, 10 rats), normal saline group(group 2, 10 rats), endostatin group(group 3, 10 rats)and avastin group(group 4, 10 rats). The drugs were injected into the mice' vitreous after photocoagulation 2wk later. Then 1wk later, we took the mice eyeballs to perform the HE and immunohistochemical staining to observe. The statistical analysis of ANOVA was done by SPSS 16.0 and the LSD-<i>t</i> test was used for multiple samples, taking <i>P</i><0.05 as the test standards.<p>RESULTS: Two weeks later, HE histopathological examination was done, light microscope showed large amount of new vessels' formation, the positive rate for CNV was 72.8%. The blank control group compared with the normal saline group <i>P</i>>0.05, had no inhibitory effect on CNV; endostatin treated group compared with control group, <i>P</i><0.05, had a certain inhibitory effect; avastin group compared with the control group, <i>P</i><0.05, had an inhibitory effect on CNV; the LSD-<i>t</i> was performed on Avastin group and endostatin group, <i>P</i><0.05, which were statistically significant. We thought that the two drugs have different inhibitory effect on mice' CNV, because <i>(-overx)</i><sub>Avastin </sub>=26.90,<i>(-overx)</i><sub>endostatin</sub>=29.13,<i>(-overx)</i><sub>Avastin</sub><<i>(-overx)</i><sub>endostatin</sub>, we can infer that endostar had lower inhibitory effect on mice CNV than Avastin.<p>CONCLUSION: Laser-induced CNV animal models of colored mice C57BL/6J is of short time and high rate establishment and it is an ideal model for CNV study. Endostar has certain inhibitory effect on CNV, and it is likely to become one of the important drugs for CNV-related diseases in the future
Preparation of Metal-Free Nitrogen-Doped Carbon Material and Its Catalytic Performance
Nitrogen-doped carbon materials (NCMs) were prepared via hydrothermal treatment together with pyrolysis under nitrogen atmosphere by using melamine as nitrogen source and sucrose as carbon source. The NCMs were characterized by X-ray diffraction (XRD), laser Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results showed that nitrogen species were successfully doped into NCMs in the formation of pyridinic N, pyrrolic N, graphitic N, and oxidized N. With the temperature of pyrolysis increasing, the total amount of nitrogen species decreased, while the proportion of graphitic N increased. The catalytic performance was investigated by the reduction of p-nitrophenol with excessive KBH4 at 30 â. The reaction rate constant can reach 1.06 min-1 for NCM-800. The NCM-800 has good stability, which can be used for 8 cycles without obvious deactivation.
Parallel Acceleration and Improvement of Gravitational Field Optimization Algorithm
The Gravitational Field Algorithm, a modern optimization algorithm, mainly simulates celestial mechanics and is derived from the Solar Nebular Disk Model (SNDM). It simulates the process of planetary formation to search for the optimal solution. Although this optimization algorithm has more advantages than other optimization algorithms in multi-peak optimization problems, it still has the shortcoming of long computation time when dealing with large-scale datasets or solving complex problems. Therefore, it is necessary to improve the efficiency of the Gravitational Field Algorithm (GFA). In this paper, an optimization method based on multi-population parallel is proposed to accelerate the Gravitational Field Algorithm. With the help of the parallel mechanism in MATLAB, the algorithm execution speed will be improved by using the parallel computing mode of multi-core CPU. In addition, this paper also improves the absorption operation strategy. By comparing the experimental results of eight classical unconstrained optimization problems, it is shown that the computational efficiency of this method is improved compared with the original Gravitational Field Algorithm, and the algorithm accuracy has also been slightly improved
Targeting EZH2 Regulates Tumor Growth and Apoptosis Through Modulating Mitochondria Dependent Cell-Death Pathway in HNSCC
EZH2 is a negative prognostic factor and is overexpressed or activated in most human cancers including head and neck squamous cell carcinoma (HNSCC). Analysis of The Cancer Genome Atlas (TCGA) HNSCC data indicated that EZH2 over-expression was associated with high tumor grade and conferred poor prognosis. EZH2 inhibition triggered cell apoptosis, cell cycle arrest and decreased cell growth in vitro. MICU1 (mitochondrial calcium uptake1) was shown to be down regulated when EZH2 expression was inhibited in HNSCC. When the EZH2 and MICU1 were inhibited, HNSCC cells became susceptible to cell cycle arrest and apoptosis. Mitochondrial membrane potential and cytosolic Ca2+ concentration analysis suggested that EZH2 and MICU1 were required to maintain mitochondrial membrane potential stability. A xenograft tumor model was used to confirm that EZH2 depletion inhibited HNSCC cell growth and induced tumor cell apoptosis. In summary, EZH2 is a potential anti-tumor target in HNSCC
Long Non Coding RNA MALAT1 Promotes Tumor Growth and Metastasis by Inducing Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma
The prognosis of advanced oral squamous cell carcinoma (OSCC) patients remains dismal, and a better understanding of the underlying mechanisms is critical for identifying effective targets with therapeutic potential to improve the survival of patients with OSCC. This study aims to clarify the clinical and biological significance of metastasis-associated long non-coding RNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in OSCC. We found that MALAT1 is overexpressed in OSCC tissues compared to normal oral mucosa by real-time PCR. MALAT1 served as a new prognostic factor in OSCC patients. When knockdown by small interfering RNA (siRNA) in OSCC cell lines TSCCA and Tca8113, MALAT1 was shown to be required for maintaining epithelial-mesenchymal transition (EMT) mediated cell migration and invasion. Western blot and immunofluorescence staining showed that MALAT1 knockdown significantly suppressed N-cadherin and Vimentin expression but induced E-cadherin expression in vitro. Meanwhile, both nucleus and cytoplasm levels of ÎČ-catenin and NF-ÎșB were attenuated, while elevated MALAT1 level triggered the expression of ÎČ-catenin and NF-ÎșB. More importantly, targeting MALAT1 inhibited TSCCA cell-induced xenograft tumor growth in vivo. Therefore, these findings provide mechanistic insight into the role of MALAT1 in regulating OSCC metastasis, suggesting that MALAT1 is an important prognostic factor and therapeutic target for OSCC
Diversity of Rotavirus Strains Causing Diarrhea in \u3c5 Years Old Chinese Children: A Systematic Review
Background: We conducted a systematic review of the diversity and fluctuation of group A rotavirus strains circulating in China.
Methods and Findings: Studies of rotavirus-based diarrhea among children less than 5 years, published in English or Chinese between 1994 and 2012, were searched in PubMed, SinoMed, and CNKI and reviewed by applying standardized algorithms. The temporal and spatial trends of genotyping and serotyping were analyzed using a random-effects model. Ninety-three studies met the inclusion/exclusion criteria and were included in the meta-analysis. Overall, 22,112 and 10,660 rotavirus samples had been examined for G and P types, respectively. The most common G types were G1 (39.5%), G3 (35.6%), G2 (1.3%), and G9 (0.1%). Among P types, P[8] (54.6%) was the predominant type, followed by P[4] (11.1%) and P6 (0.1%). The most common G-P combinations were G3P[8] (32.1%) and G1P[8] (24.5%), followed by G2P[6] (13.2%) and G2P[4] (10.1%). Before 2000, serotype G1 was the predominant strain and accounted for 74.3% of all rotavirus infections; however, since 2000, G3 (45.2%) has been the predominant strain. Rotavirus P types showed little variation over the study period.
Conclusion: Despite the variation of serotypes observed in China, the G1, G2, G3, and G4 serotypes accounted for most rotavirus strains in recent decades. These results suggest that Chinese children will be adequately protected with currently available or forthcoming rotavirus vaccines
Building KCNQ1/KCNE1 Channel Models and Probing their Interactions by Molecular-Dynamics Simulations
The slow delayed rectifier (IKs) channel is composed of KCNQ1 (pore-forming) and KCNE1 (auxiliary) subunits, and functions as a repolarization reserve in the human heart. Design of IKs-targeting anti-arrhythmic drugs requires detailed three-dimensional structures of the KCNQ1/KCNE1 complex, a task made possible by Kv channel crystal structures (templates for KCNQ1 homology-modeling) and KCNE1 NMR structures. Our goal was to build KCNQ1/KCNE1 models and extract mechanistic information about their interactions by molecular-dynamics simulations in an explicit lipid/solvent environment. We validated our models by confirming two sets of model-generated predictions that were independent from the spatial restraints used in model-building. Detailed analysis of the molecular-dynamics trajectories revealed previously unrecognized KCNQ1/KCNE1 interactions, whose relevance in IKs channel function was confirmed by voltage-clamp experiments. Our models and analyses suggest three mechanisms by which KCNE1 slows KCNQ1 activation: by promoting S6 bending at the Pro hinge that closes the activation gate; by promoting a downward movement of gating charge on S4; and by establishing a network of electrostatic interactions with KCNQ1 on the extracellular surface that stabilizes the channel in a pre-open activated state. Our data also suggest how KCNE1 may affect the KCNQ1 pore conductance
Uterine NDRG2 expression is increased at implantation sites during early pregnancy in mice, and its down-regulation inhibits decidualization of mouse endometrial stromal cells
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