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Search Results: 1 - 10 of 32838 matches for " Tongfeng Guo "
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Single-Step Tunable Group Delay Phaser for Real-Time Spectrum Sniffing
Tongfeng Guo,Qingfeng Zhang,Yifan Chen,Rui Wang,Christophe Caloz
Physics , 2015,
Abstract: This paper presents a single-step tunable group delay phaser for spectrum sniffing. This device may be seen as a "time filter", where frequencies are suppressed by time separation rather than by spectral attenuation. Compared to its multiple-step counterpart, this phaser features higher processing resolution, greater simplicity, lower loss and better channel equalization, due to the smaller and channel-independent group delay swing. A three-channel example is provided for illustration.
Association of the apolipoprotein A5 gene -1131 T>C polymorphism with fasting blood lipids: a meta-analysis in 37859 subjects
Tongfeng Zhao, Jiangpei Zhao
BMC Medical Genetics , 2010, DOI: 10.1186/1471-2350-11-120
Abstract: We limited our analysis to the following four blood lipid variables: total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Subjects were confined to adults who were at least 18 years old. A dominant model was used for this meta-analysis. 37 studies with 37859 subjects were included in this meta-analysis.The results showed that the carriers of -1131C allele have higher blood TC and TG than the non-carriers: standardized mean difference (SMD) = 0.08, 95% confidence interval (CI, 0.05, 0.11), P < 0.00001, Pheterogeneity = 0.42, and SMD = 0.31, 95% CI (0.27, 0.34), P < 0.00001, Pheterogeneity = 0.0003, respectively. Significant association between the -1131 T>C polymorphism and lower blood HDL-C was also detected under the dominant model: SMD = -0.17, 95% CI (-0.21, -0.14), P < 0.00001, Pheterogeneity = 0.003.Our meta-analysis supports the strong association of the APOA5 -1131 T>C polymorphism with higher levels of TC and TG, and lower levels of HDL-C.Hyperlipidemia, which is considered to be one of the most important risk factors for coronary heart disease (CHD) and stroke, is characterized by the derangements of one or many of the lipids: elevations of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and/or triglycerides (TG), or low levels of high-density lipoprotein cholesterol (HDL-C) [1]. Although a large number of studies have tried to elucidate the pathogenesis of the disease, the exact underlying mechanisms are still not completely understood [2]. In recent years, much has been learned about specific genes that influence hyperlipidemia [3]. However, due to various reasons, including considerable heterogeneity of the disease, the identification of susceptibility genes is difficult and most associations have not been replicated [3].More recently, apolipoprotein A5 (APOA5) was identified as a strong modulator of blood lipids [4]. The APOA5 is predominantly synth
Hypoxia-inducible factor-1α gene polymorphisms and cancer risk: a meta-analysis
Tongfeng Zhao, Jing Lv, Jiangpei Zhao, Marius Nzekebaloudou
Journal of Experimental & Clinical Cancer Research , 2009, DOI: 10.1186/1756-9966-28-159
Abstract: The meta-analysis for 1772 C/T polymorphism included 4131 cancer cases and 5387 controls, and for 1790 G/A polymorphism included 2058 cancer cases and 3026 controls. Allelic and genotypic comparisons between cases and controls were evaluated. Subgroup analyses by cancer types, ethnicity, and gender were also performed. We included prostate cancer in male subgroup, and female specific cancers in female subgroup.For the 1772 C/T polymorphism, the analysis showed that the T allele and genotype TT were significantly associated with higher cancer risk: odds ratio (OR) = 1.29 [95% confidence interval (CI, 1.01, 1.65)], P = 0.04, Pheterogeneity < 0.00001, and OR = 2.18 [95% CI (1.32, 3.62)], P = 0.003, Pheterogeneity = 0.02, respectively. The effect of the genotype TT on cancer especially exists in Caucasians and female subjects: OR = 2.40 [95% CI (1.26, 4.59)], P = 0.008, Pheterogeneity = 0.02, and OR = 3.60 [95% CI (1.17, 11.11)], P = 0.03, Pheterogeneity = 0.02, respectively. For the 1790 G/A polymorphism, the pooled ORs for allelic frequency comparison and dominant model comparison suggested a significant association of 1790 G/A polymorphism with a decreased breast cancer risk: OR = 0.28 [95% CI (0.08, 0.90)], P = 0.03, Pheterogeneity = 0.45, and OR = 0.29 [95% CI (0.09, 0.97)], P = 0.04, Pheterogeneity = 0.41, respectively. The frequency of the HIF-1α 1790 A allele was very low and only two studies were included in the breast cancer subgroup.Our meta-analysis suggests that the HIF-1α 1772 C/T polymorphism is significantly associated with higher cancer risk, and 1790 G/A polymorphism is significantly associated with decreased breast cancer risk. The effect of the 1772 C/T polymorphism on cancer especially exists in Caucasians and female subjects. Only female specific cancers were included in female subgroup, which indicates that the 1772 C/T polymorphism is significantly associated with an increased risk for female specific cancers. The association between the 1790 G/A
Complexity and characteristic frequency studies in ECG signals of mice based on multiple scale factors
XiaoDong Yang,AiJun He,Peng Liu,TongFeng Sun,XinBao Ning
Science China Life Sciences , 2011, DOI: 10.1007/s11427-011-4173-y
Abstract: Existing methods of physiological signal analysis based on nonlinear dynamic theories only examine the complexity difference of the signals under a single sampling frequency. We developed a technique to measure the multifractal characteristic parameter intimately associated with physiological activities through a frequency scale factor. This parameter is highly sensitive to physiological and pathological status. Mice received various drugs to imitate different physiological and pathological conditions, and the distributions of mass exponent spectrum curvature with scale factors from the electrocardiogram (ECG) signals of healthy and drug injected mice were determined. Next, we determined the characteristic frequency scope in which the signal was of the highest complexity and most sensitive to impaired cardiac function, and examined the relationships between heart rate, heartbeat dynamic complexity, and sensitive frequency scope of the ECG signal. We found that all animals exhibited a scale factor range in which the absolute magnitudes of ECG mass exponent spectrum curvature achieve the maximum, and this range (or frequency scope) is not changed with calculated data points or maximal coarse-grained scale factor. Further, the heart rate of mice was not necessarily associated with the nonlinear complexity of cardiac dynamics, but closely related to the most sensitive ECG frequency scope determined by characterization of this complex dynamic features for certain heartbeat conditions. Finally, we found that the health status of the hearts of mice was directly related to the heartbeat dynamic complexity, both of which were positively correlated within the scale factor around the extremum region of the multifractal parameter. With increasing heart rate, the sensitive frequency scope increased to a relatively high location. In conclusion, these data provide important theoretical and practical data for the early diagnosis of cardiac disorders.
Expression of Human Globular Adiponectin-Glucagon-Like Peptide-1 Analog Fusion Protein and Its Assay of Glucose-Lowering Effect In Vivo
Tongfeng Zhao, Jing Lv, Jiangpei Zhao, Xiao Huang, Haijuan Xiao
International Journal of Medical Sciences , 2011,
Abstract: In this study, human globular adiponectin-glucagon-like peptide-1 analog (gAd-GLP-1-A) fusion protein was expressed and its glucose-lowering effect was measured in vivo. We constructed a prokaryotic expression vector PET28a-gAd-GLP-1-A and transformed the vector into Escherichia coli BL21 (DE3). A recombinant fusion protein of about 25KD was expressed from BL21 (DE3) cells after isopropylthio-β-D-galactoside induction. This protein was N-terminal His-tagged gAd-GLP-1-A fusion protein. Most of the protein was expressed in inclusion body. The fusion protein in inclusion body was purified by using High-Affinity Nickel Iminodiacetic Acid Resin and refolded in urea gradient refolding buffer. The refolded protein was incubated with enterokinase to remove the N-terminal His-tag. The fusion protein without His-tag is gAd-GLP-1-A fusion protein, which exhibited significant glucose-lowering effect in diabetic mice.
Cardioprotective Effect of Sodium Ferulate in Diabetic Rats
Xiaohong Xu, Haijuan Xiao, Jiangpei Zhao, Tongfeng Zhao
International Journal of Medical Sciences , 2012,
Abstract: Reactive oxygen species (ROS) play important roles in the occurrence and development in diabetic cardiomyopathy (DC). Ferulic acid is one of the ubiquitous compounds in diet. Sodium ferulate (SF) is its sodium salt. SF has potent free radical scavenging activity and can effectively scavenge ROS. The study investigated the effect of SF on cardioprotection in diabetic rats. The diabetic rats induced by streptozotocin (STZ) were treated with SF (110mg/kg) by gavage per day for 12 weeks. Results showed that the levels of nitric oxide (NO) and superoxide dismutase (SOD) activity in plasma and myocardium in SF-treated group were significantly higher than those in diabetic control group. The levels of malondialdehyde (MDA) in plasma and myocardium in SF-treated group were significantly lower than those in diabetic control group. Expression of connective tissue growth factor (CTGF) in myocardium in SF-treated group was apparently lower than that in diabetic control group. Compared with normal control group, electron micrographs of myocardium in diabetic control group showed apparently abnormality, while that was significantly ameliorated in SF-treated group. The study demonstrated that SF has a cardioprotective effect via increasing SOD activity and NO levels in plasma and myocardium, inhibiting oxidative stress in plasma and myocardium, and inhibiting the expression of CTGF in myocardium in diabetes rats.

YE Ruizeng,XU Zhichao,GE Zhanying,GAO Liang Beijing University of Iron,Steel Technology,YU Tongfeng,ZHANG Rungang,LI Lijia,ZHANG Peihuan Xingdu Machine Works,

金属学报 , 1985,
Chromatographic Analysis of Trace Impurities in Acrylamide

Xiu Zhenjia,Zhang Tongfeng,Luo Chunrong,Xu Guowang,Zhang Yukui,

色谱 , 1995,
Abstract: 丙烯酰胺中痕量杂质色谱分析修振佳,张桐凤,罗春荣,许国旺,张玉奎(中国科学院大连化学物理研究所,国家色谱研究分析中心大连116012)1前言合成聚丙烯酰胺的单体丙烯酰胺的纯度可能影响其聚合速度和产物的分子量,为保证聚丙烯酰胺产品质量,分析单体丙烯酰胺...
The Quasi-Static Approximation of Heat Waves in Anisotropic Thermo-Elastic Media  [PDF]
Shaohua Guo
Applied Mathematics (AM) , 2010, DOI: 10.4236/am.2010.15054
Abstract: The equilibrium equations of anisotropic media, coupled to the heat conduction equations, are studied here based on the standard spaces of the physical presentation, in which an new thermo-elastic model based on the second law of thermodynamics is induced. The uncoupled heat wave equation for anisotropic media is deduced. The results show that the equation of heat wave is of the properties of dissipative waves. In final part of this paper, we discuss the propagation behaviour of heat waves for transversely isotropic media.
A Second-Order Eigen Theory for Static Electromagnetic Fields  [PDF]
Shaohua Guo
Journal of Modern Physics (JMP) , 2010, DOI: 10.4236/jmp.2010.12015
Abstract: The static electromagnetic fields are studied here based on the standard spaces of the physical presentation, and the modal equations of static electromagnetic fields for anisotropic media are deduced. By introducing a set of new potential functions of order 2, several novel theoretical results were obtained: The classical potential functions of order 1 can be expressed by the new potential functions of order 2, the electric or magnetic potentials are scalar for isotropic media, and vector for anisotropic media. The amplitude and direction of the vector potentials are related to the anisotropic subspaces. Based on these results, we discuss the laws of static electromagnetic fields for anisotropic media.
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