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A 4th-Order Low-distortion Low-pass ΣΔ Modulator Using Timing-Sharing Technique
Hong-guo Zhang,Ji-bao Zhang,Ming-yuan Ren 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.9
A 4th-Order low-distortion low-pass ΣΔ modulator structure is proposed in this paper, which uses the timing-sharing between the 3rd and 4th integrators during one clock phase. Compared with conventional cascade of integrators with distributed feed-forward (CIFF) sigma-delta modulator structure, the proposed structure not only solves the critical timing issue for the quantizer and feedback DAC path, but also eliminates an extra active adder to sum up the input feed-forward. By methods of delay redistribution structure, the time for quantization and feedback dynamic element match (DEM) operation can be extended from a non-overlapping interval for a conventional low-distortion structure to half of the sampling clock period. Capacitive input feed-forward (CIF) methodology eliminates the adder in front of the quantizer. Further, the op-amp of the last integrator is used as an active adder by op-amp sharing. Therefore, the power consumption can be reduced and the linearity of the feedback DAC is improved because of the increasing time which used for implementation of DEM algorism. The proposed 4th-Order low-distortion low-pass ΣΔ modulator with 4-bit quantizer is simulated in MATLAB. From the simulation results, the proposed structure can achieve a peak SNR (signal- to-noise ratio) of 87dB with 2.5MHz bandwidth under 32 oversampling ratio at 160MHz sampling frequency and the ENOB of 14.234bits in non-ideal condition.
Hong-Guan Xie,Yong-Gang Bao,Li-ping Bai,Jun-Jie Shan,Rong Jiang,Yang Zhang,Lian-Hong Guo,Ren Zhang,Yuan Li 한국미생물학회 2009 The journal of microbiology Vol.47 No.2
Streptomyces sp. 139 generates a novel exopolysaccharide (EPS) designated as Ebosin, which exerts an antagonistic effect on IL-1R in vitro and anti-rheumatic arthritis activity in vivo. A ste gene cluster for Ebosin biosynthesis consisting of 27 ORFs was previously identified in our laboratory. In this paper, ste16 was expressed in Escherichia coli BL21 and the recombinant protein was purified, which has the ability to catalyze the transfer of the methyl group from S-adenosylmethionine (AdoMet) to dTDP-4-keto-6-deoxy-D-glucos, which was thus identified as a methyltransferase. In order to determine the function of ste16 in Ebosin biosynthesis, the gene was disrupted with a double crossover via homologous recombination. The monosaccharide composition of EPS-m generated by the mutant strain Streptomyces sp. 139 (ste16-) was found to differ from that of Ebosin. The IL-1R antagonist activity of EPS-m was markedly lower than that of Ebosin. These experimental results have shown that the ste16 gene codes for a methyltransferase which is involved in Ebosin biosynthesis.
Deuterium Clusters Fusion Induced by the Intense Femtosecond Laser Pulse
Hong-Jie, Liu,Zhi-Jian, Zheng,Yu-Qiu, Gu,Bao-Han, Zhang,Yong-Joo, Rhee,Sung-Mo, Nam,Jae-Min, Han,Yong-Woo, Rhee,Kwon-Hae, Yea,Jia-Bin, Chen,Hong-Bin, Wang,Chun-Ye, Jiao,Ying-Ling, He,Tian-Shu, Wen,Xia ALLERTON PRESS INC 2007 CHINESE PHYSICS LETTERS Vol.24 No.2
<P>Neutrons (2.45 MeV) from deuterium cluster fusion induced by the intense femtosecond (30 fs) laser pulse are experimentally demonstrated. The average neutron yield 10<SUP>3</SUP> per shot is obtained. It is found that the yield slightly increases with the increasing laser spot size. No neutron can be observed when the laser intensity I < 4.3×10<SUP>15</SUP> W/cm<SUP>2</SUP>.</P>
Antioxidant Flavone Glycosides from the Root of Pteroxygonum giraldii
Bao-Lin Li,Lin-Ling Jiang,Hui-Chun Wang,Zhan-Jun Yang,Xi-Quan Zhang,Hong-Mei Gu,Xian-Hua Tian 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.7
Two new flavone glycosides, giraldiin A and B, together with three known compounds, annulatin, myricetin 3-O-α-L-rhamnopyranoside and gallic acid, were isolated from the ethanol extract of the root of Pteroxygonum giraldii Damm. et Diels. The structures of giraldiin A and B are designated as 3'-(α-L-arabinopyranosyloxy)-4',5,5',7-tetrahydroxy-3-methoxyflavone and 4'-(β-D-glucopyranosyloxy)-5,5',7-trihydroxy-2',3-dimethoxyflavone, respectively,on the basis of detailed spectroscopic analyses. The free radical scavenging activity of giraldiin A was evaluated by decolouring spectrophotometry of pentamethine cyanine dye (Cy5) with Fe2+-H2O2 Fenton radical generating system. The results indicated the hydroxyl free radical scavenging activity of giraldiin A (ED50 = 23.7 nmol/mL) is higher than that of some known antioxidants such as rutin, puerarin, daidzein and 2,6-di-tertbutyl-4-methylphenol.
Zhang Han-Wen,Zhang Qin-Jin,Liu Yan-Cheng,Wang Hong-Lai,Hu Wang-Bao 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.6
Traditional virtual DC motor control can suppress the bus voltage fl uctuations caused by load power mutations and distributed generation fl uctuations. However, the dynamic response is poor and the load current sharing cannot be adjusted. Thus, a modifi ed virtual DC generator control strategy is proposed, which combines the average current controller with the virtual DC generator to enhance current sharing eff ect. The adaptive regulation equations of inertia coeffi cient and damping coeffi cient are elaborated simultaneously to improve the system dynamic characteristics. Then the infl uence of key control parameters on system stability is analyzed by establishing the small signal model. Finally, simulations and a StarSim HIL experimental platform of DC microgrid are built. The results show that the proposed method can eff ectively suppress the DC bus voltage fl uctuations and enable them to have a better dynamic response, while realizing the accurate current sharing.
Zhang, Song,Huang, Wei-Bin,Wu, Li,Wang, Lai-You,Ye, Lian-Bao,Feng, Bing-Hong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.10
$N^1$-(2, 5-dimethoxyphenyl)-$N^8$-hydroxyoctanediamide (N25) is a novel SAHA cap derivative of HDACi, with a patent (No. CN 103159646). This invention is a hydroxamic acid compound with a structural formula of $RNHCO(CH_2)6CONHOH$ (wherein R=2, 5dimethoxyaniline), a pharmaceutically acceptable salt which is soluble. In the present study, we investigated the effects of N25 with regard to drug distribution and molecular docking, and anti-proliferation, apoptosis, cell cycling, and $LD_{50}$. First, we designed a molecular approach for modeling selected SAHA derivatives based on available structural information regarding human HDAC8 in complex with SAHA (PDB code 1T69). N25 was found to be stabilized by direct interaction with the HDAC8. Anti-proliferative activity was observed in human glioma U251, U87, T98G cells and human lung cancer H460, A549, H1299 cells at moderate concentrations ($0.5-30{\mu}M$). Compared with SAHA, N25 displayed an increased antitumor activity in U251 and H460 cells. We further analyzed cell death mechanisms activated by N25 in U251 and H460 cells. N25 significantly increased acetylation of Histone 3 and inhibited HDAC4. On RT-PCR analysis, N25 increased the mRNA levels of p21, however, decreased the levels of p53. These resulted in promotion of apoptosis, inducing G0/G1 arrest in U251 cells and G2/M arrest in H460 cells in a time-dependent and dose-dependent manner. In addition, N25 was able to distribute to brain tissue through the blood-brain barrier of mice ($LD_{50}$: 240.840mg/kg). In conclusion, our findings demonstrate that N25 will provide an invaluable tool to investigate the molecular mechanism with potential chemotherapeutic value in several malignancies, especially human glioma.
Bao-Ke Ma,Li-Xin Guo,Hong-Tao Su,Bei-Chen Zhang 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.8
If the relatively larger convection electric field and small the collision frequency between ions andneutrals in the high-latitude ionosphere are considered, the integral solution of the non-Maxwellianion velocity distribution function for the relaxation collision model is simplified, and a torus distributionfunction of the ion velocity is obtained. Also, the feature of the torus velocity distributionfunction is analyzed and simulated with different parameters in high-latitude ionosphere. Furthermore,by using the electromagnetic radiation theory of Sheffield and taking into account the iontemperature anisotropy and its variation with the electric field, we simulate the incoherent scatteringspectrum of ions in different directions. The research shows that the ionospheric convectionelectric field, the ion-neutral collision frequency and the ion anisotropic temperature distributionall have an effect on the incoherent scattering spectrum.
Steroid Receptor Coactivator-3 Promotes Bladder Cancer Through Upregulation of CXCR4
Zhang, Yu,Wang, Ji-Hong,Liu, Bin,Qu, Ping-Bao Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6
The three homologous members of the p160 SRC family (SRC-1, SRC-2 and SRC-3) mediate the transcriptional functions of nuclear receptors and other transcription factors, and are the most studied of all the transcriptional co-activators. Recent work has indicated that the SRC-3 gene is subject to amplification and overexpression in various human cancers. Some of the molecular mechanisms responsible for SRC overexpression, along with the mechanisms by which SRC-3 promotes breast and prostate cancer cell proliferation and survival, have been identified. However, the function of SRC-3 in bladder cancer remains poorly understood. In the present study, our results indicate that overexpression of SRC-3 promotes bladder cancer cell proliferation whereas knockdown of SRC-3 results in inhibition. At the molecular level, we further established that CXCR4 is a transcriptional target of SRC-3. Therefore, our study first identified that SRC-3 plays a critical role in the bladder cancer, which may be a target beneficial for its prevention and treatment.
Tissue distribution of sialic acid-linked influenza virus receptors in beagle dogs
Zhang-Yong Ning,Xin-Tao Wu,Yan-Fen Cheng,Wen-Bao Qi,Yu-Fu An,Heng Wang,Gui-Hong Zhang,Shou-Jun Li 대한수의학회 2012 Journal of Veterinary Science Vol.13 No.3
Reports of influenza A virus infections in dogs has received considerable attention from veterinarians, virologists, and epidemiologists. Interaction between influenza viral hemagglutinin and cell oligosaccharides containing sialic acid residues results in infection. Sialic acids have an α-2,3-linkage to the penultimate galactose in the avian influenza virus receptor and an α-2,6-linkage in the human receptor. To date,there are no detailed data on the tissue distribution or histological features of either type of sialic acid-linked influenza virus receptors in beagle dogs, which are common laboratory animals and pets. We conducted the current study to visualize the in situ tissue distribution of both sialic acid-linked influenza virus receptors in various organs of beagle dogs using Maackia amurensis lectin II and Sambucus nigra agglutinin. Both α-2,3- and α-2,6-sialic acid-linked receptors were detected in the endothelial cells of the respiratory tract and other organs. Endothelial cells of most gastrointestinal organs were negative for α-2,3-sialic acid-linked receptors in the dogs. Our results suggested that these canine organs may be affected by influenza virus infection. The findings from our study will also help evaluate the occurrence and development of influenza virus infections in dogs.