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ABSTRACT: Toll-like receptors (TLRs) have been widely known for their role as an important mediator of immune reactions in the development and progression of atherosclerotic (AS) lesions, which play the most important role in the occurrence of cerebral infarction (CI). The lipopolysaccharide (LPS)-lipopolysaccharide binding protein (LBP) compounds connect LPS receptor-CD14 and play an important role in promoting inflammatory reaction through TLRs. This study was designed to study whether LBP genetic polymorphisms are associated with CI risk in a Chinese population. LBP c.291T>C and c.1306T>C single nucleotide polymorphisms (SNPs) were genotyped in 366 CI cases and 200 controls from Changsha by using method of Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Blood lipid and lipoprotein levels were also detected and the intima-media thickness (IMT) of carotid arteries were determined. No significant difference in genotype and allele distribution of the LBP c.291T>C and LBP c.1306T>C polymorphism was observed between the cases and controls (P > 0.05). CI patients carrying the TC genotype for both LBP c.291T>C and c.1306T>C polymorphisms showed higher carotid IMT than those carrying the TT genotype (P < 0.05, respectively). LBP c.291T>C and c.1306T>C polymorphisms were significantly associated with carotid IMT in Changsha, China, but both polymorphisms were not associated with risk of atherosclerotic CI.
Journal of Thrombosis and Thrombolysis 04/2012; 34(2):260-8. · 1.48 Impact Factor
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Endoscopy 04/2012; 44 Suppl 2 UCTN:E131-2. · 5.21 Impact Factor
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ABSTRACT: Dewatering of fine clean coal slurry is one of the most important unit operations of a coal-cleaning circuit. However, an efficient and economic dewatering method is still eluding the coal industry. In this study hyperbaric (high pressure) filtration studies were conducted on a froth flotation product obtained from a coal preparation plant processing Pittsburgh No. 8 seam coal. The fine coal slurry (42 weight percent minus 25 µm) could be dewatered to a low moisture (24%) using 482 kPa (70 psi) pressure. This article describes two novel approaches for improving dewatering of the fine coal slurry using hyperbaric filtration, such as using a modified filter support and split-size dewatering. The modified filter support system and the split-sizing at 25 µm (500 mesh) provided 21.5% and 15.9% moisture filter cake, which was about 10% and 34% improvement in moisture reduction in the filter cake moisture, respectively. Combining both the approaches with the addition of a nonionic flocculant provided a filter cake with 10.5% moisture, which was about a 56% improvement in moisture reduction.
International Journal of Coal Preparation and Utilization 01/2010; 30(1):32-43. · 0.29 Impact Factor
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Z.P. Wei,
B. Yao, X.H. Wang,
Z.Z. Zhang,
Y.M. Lu,
D.Z. Shen,
B.H. Li,
J.Y. Zhang,
D.X. Zhao,
X.W. Fan,
Z.K. Tang
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ABSTRACT: A wurtzite nitrogen-doped MgZnO (MgZnO:N) film was grown by plasma-assisted molecular-beam epitaxy (PAMBE) on c-plane sapphire using radical NO as oxygen source and nitrogen dopant. The as-grown film shows n-type conduction at room temperature, but transforms into p-type conduction after annealed. Photoluminescence (PL) spectrum measured at 80 K is dominated by neutral donor-bound exciton emission (D0X) located at 3.522 eV for the n-type MgZnO:N film, but by neutral acceptor-bound exciton emission (A0X) located at 3.515 eV for the p-type MgZnO:N film. By fitting exciton emission intensity of temperature-dependent PL spectra, the binding energies of the D0X and A0X were estimated to be 32 and 43 meV, respectively. Based on the energy shift of exciton emission, the band gap of the MgZnO:N film is estimated to be 3.613 eV, which is 179 meV larger than that of ZnO. Using the Haynes rule, the acceptor energy level of the MgZnO:N film was evaluated to be about 176 meV above the valence band.
Journal of Materials Research. 09/2007; 22(10):2791 - 2795.
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C.X. Cong,
B. Yao,
Y.P. Xie,
G.Z. Xing,
B.H. Li, X.H. Wang,
Z.P. Wei,
Z.Z. Zhang,
Y.M. Lv,
D.Z. Shen,
X.W. Fan
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ABSTRACT: MgxZn1−xO films were grown on quartz substrates at 773 K by using radio frequency magnetron sputtering with a mixture of argon and nitrogen as sputtering gases. The nitrogen concentration in the mixture is characterized by the nitrogen partial pressure ratio, which is determined by the ratio of nitrogen flow rate to the flow rates of nitrogen and argon. It was found that Mg concentration, structure, and band gap of the MgxZn1−xO film could be tuned by changing the nitrogen partial pressure ratio of the sputtering gases. The Mg concentration in the MgxZn1−xO film increases with increasing nitrogen partial pressure ratio. The MgxZn1−xO film consists of wurtzite phase at the ratios from 0% to 50%, mixture of wurtzite and cubic phases at the ratios between 50% and 83%, and cubic phase at 100%. The band gap of the MgxZn1−xO film with wurtzite and cubic structure increases as the ratio rises. The variation of the structure and band gap is attributed to change of the Mg concentration, which results from loss of the O and Zn atoms during growth process, the former is induced by reaction between N and O, and the latter by re-evaporation of Zn atoms due to high substrate temperature. The mechanism of the loss of the O and Zn atoms is discussed based on thermodynamics.
Journal of Materials Research. 09/2007; 22(10):2936 - 2942.
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ABSTRACT: Well-aligned ZnO nanowire arrays have been successfully synthesized on Si(100) substrate by a vapour transport process. A ZnO thin film was used as the nucleation sites, which can control the growth orientation of the nanowires. By observation of the initial process of nanowire growth, a vapour transport solid condensation mechanism was proposed for ZnO nanowire growth, in which the role of ZnO thin film was to provide nucleation sites for nanowire growth. It was also found that the nanowire density could be adjusted by varying the thickness of the ZnO thin film. The synthesized ZnO nanowires, which had a single-crystalline wurtzite structure, had diameters of 50–120 nm and lengths of around 5 µm. The strong ultraviolet emission and weak deep level emission reflect the high optical quality of the nanowires.
Nanotechnology 05/2007; 18(23):235604. · 3.98 Impact Factor
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X H Wang,
B Yao,
Z P Wei,
D Z Sheng,
Z Z Zhang,
B H Li,
Y M Lu,
D X Zhao,
J Y Zhang,
X W Fan,
L X Guan,
C X Cong
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ABSTRACT: A lithium (Li) and nitrogen (N) dual-doped p-type ZnO film (ZnO : (Li,N)) was deposited on c-plane sapphire by RF-magnetron sputtering of Zn–2 at.% Li alloy using mixed gases of oxygen and nitrogen and then annealing in N2 flow. It has a carrier concentration of 3.07 × 1016 cm−3 and Hall mobility of 1.74 cm2 V−1 s−1. XPS measurement shows that there are LiZn–N complexes in the p-type ZnO : (Li,N), which are demonstrated by photoluminescence measured at various temperatures and different excitation powers to be acceptors and responsible for p-type conductivity of the ZnO : (Li,N). The optical level of the LiZn–N complex acceptor is estimated to be about 126 meV by measurement of emission energy of free electron to the acceptor level.
Journal of Physics D Applied Physics 10/2006; 39(21):4568. · 2.54 Impact Factor
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B. Yao,
D. Z. Shen,
Z. Z. Zhang, X. H. Wang,
Z. P. Wei,
B. H. Li,
Y. M. Lv,
X. W. Fan,
L. X. Guan,
G. Z. Xing,
C. X. Cong,
Y. P. Xie
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ABSTRACT: A yellow-orange nitrogen-doped zinc oxide (ZnO:N) film was deposited on a quartz glass substrate at 510 K by reactive radio-frequency magnetron sputtering of a ZnO target with sputtering gas of nitrogen. The lattice constants of the as-grown ZnO:N are much larger than those of undoped ZnO, and decrease with increasing annealing temperature due to escape of the nitrogen from the ZnO:N and decrease of tensile stress, accompanied with color change from yellow-orange to pale yellow. The nitrogen occupies two chemical environments in the ZnO:N based on x-ray photoelectron spectroscopy measurement. One is NO acceptor formed by substitution of N atom for O sublattice, and another is (N2)O double donors produced by substitution of N molecular for O site, which make the lattice constants expanded. The as-grown ZnO:N film shows insulating, but behaves p-type conduction in the dark after annealed at 863 K for 1 h under 10−3 Pa. Unfortunately, the p-type conduction is not stable and reverts to n type soon. However, after illuminated by sunlight for several minutes, the n-type ZnO:N transforms into p type again. The mechanism of the transformation of the conductivity behavior is discussed in the present work.
Journal of Applied Physics 06/2006; 99(12):123510-123510-5. · 2.17 Impact Factor
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ABSTRACT: Li-doped p-type ZnO was fabricated by heat treatment of Zn–Li alloy film with 2 at% Li on a quartz substrate in N2 flow at 500 °C for 2 h, and then in O2 flow at 700 °C for 1 h. The room-temperature resistivity was measured to be 678.34 Ω cm with a Hall mobility of 1.03 cm2 V−1 s−1 and a carrier concentration of 8.934 × 1015 cm−3. Three emission peaks centred at 3.347, 3.302 and 3.234 eV are observed in the photoluminescence spectrum measured at 12 K and are due to neutral acceptor-bound exciton emission, conduction band to acceptor level transition and donor–acceptor pair recombination emission, respectively. The p-type conduction of the Li-doped ZnO may be attributed to the formation of a LiZn–N complex acceptor. The optical level of the acceptor is estimated to be about 137 meV. The mechanism of formation of the Li-doped p-type ZnO is discussed in the present work.
Semiconductor Science and Technology 03/2006; 21(4):494. · 1.72 Impact Factor
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X H Wang,
M Connor,
D Wilson,
H I Wilson,
G M Nicholson,
R Smith,
D Shaw,
J P Mackay,
P F Alewood,
M J Christie,
G F King
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ABSTRACT: We have isolated a novel family of insect-selective neurotoxins that appear to be the most potent blockers of insect voltage-gated calcium channels reported to date. These toxins display exceptional phylogenetic specificity, with at least a 10,000-fold preference for insect versus vertebrate calcium channels. The structure of one of the toxins reveals a highly structured, disulfide-rich core and a structurally disordered C-terminal extension that is essential for channel blocking activity. Weak structural/functional homology with omega-agatoxin-IVA/B, the prototypic inhibitor of vertebrate P-type calcium channels, suggests that these two toxin families might share a similar mechanism of action despite their vastly different phylogenetic specificities.
Journal of Biological Chemistry 11/2001; 276(43):40306-12. · 4.77 Impact Factor
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ABSTRACT: We have isolated and determined the amino acid sequence of a novel peptide component from the venom of the Australian funnel-web spider Hadronyche versuta. This 68-residue toxin, ACTX-Hvf17, does not function like classical neurotoxins in modulating ion channel function as evidenced by its lack of insecticidal activity and its inability to affect vertebrate smooth or skeletal muscle contractility. The peptide shows significant sequence homology with mamba intestinal toxin 1 (MIT1) and to a lesser extent with a variety of colipases. The strong structural homology between MIT1 and porcine colipase leads us to propose that ACTX-Hvf17 also adopts the MIT1/colipase three-dimensional fold. However, we show that ACTX-Hvf17 has no colipase activity and does not stimulate muscle contractility like MITI. We also show that MIT1 and ACTX-Hvf17 display significant sequence homology with the C-terminal cysteine-rich domain of the Dickkopf-1 family of proteins that induce head formation in developing embryos, which leads us to propose that this domain of Dickkopf-1 also adopts the MIT1 colipase fold.
Toxicon 04/2000; 38(3):429-42. · 2.51 Impact Factor
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ABSTRACT: The objective of the project is to conduct extensive fundamental studies on the surface reactivity and surface hydrophobicity of coal-pyrites using various surface characterization techniques and to understand how the alteration of the coal-pyrite surface affects the efficiency of pyrite rejection in coal flotation. During this reporting period, the influence of the impurity content, particularly coal/carbon content, on the electrochemical oxidation of pyrite surfaces was investigated. The studies demonstrate that the coal/carbon content in coal-pyrite has a determining effect on the surface reactivity of pyrite. The oxidation behavior of high carbon-content coal-pyrite is completely different from that of purer coal-pyrite and ore-pyrite. The effects of flotation gases on the flotation behavior of coal and the surface hydrophobicity of various coal-pyrite were investigated. It was found from the lab-scale column flotation studies that among the various gases studied (air, oxygen, argon, nitrogen and carbon dioxide), carbon dioxide produced the best results with a combustible recovery of 90% and ash-content of less than 9 percent. Finally, the surface energetic studies revealed that the surfaces of pyrites and coals produced by wet grinding is more heterogenous than that prepared by dry grinding.
12/1991;
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ABSTRACT: The Adriatic Sea general circulation model coupled to a third generation wave model SWAN and a sediment transport model was implemented in the Adriatic Sea to study the dynamics of the sediment transport and resuspension in the northern Adriatic Sea (NAS) during the Bora event in January 2001. The bottom boundary layer (BBL) was resolved by the coupled model with high vertical resolution, and the mechanism of the wave–current interaction in the BBL was also represented in the model. The study found that, during the Bora event of 13–17 January 2001, large waves with significant wave height 2 m and period of 5 s were generated by strong winds in the northwestern shelf of the Adriatic where the direction of wave propagation was orthogonal to the current. The combined motion of the wave and current in the BBL increased the bottom stress over the western Adriatic shelf, resulting in stronger sediment resuspension there. Combining stronger bottom resuspension and strong upward vertical flux of resuspended sediments due to turbulent mixing, the model predicted that sediment concentration near the Po River was much higher than that predicted by the model run without wave forcing. The study also shows that wave–current interaction in the BBL reduced the western Adriatic Coastal Currents (WACCs) in the shallower north. It is concluded that wave forcing significantly changed the sediment distributions and increased the total horizontal fluxes over the western shelf. These results signified wave effect on sediment flux and distribution in the NAS, and suggested that waves cannot be neglected in the study of dynamics of sediment transport and resuspension in the shallow coastal seas. By including the tidal forcing in the coupled model, we also examined the effect of tides on the sediment transport dynamics in the NAS.
Continental Shelf Research.
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ABSTRACT: In a power transmission cable system, the uniformly configuration of the cables between sections is sometimes difficult to achieve because of the geometrical limitation. This will cause the increase of sheath circulating current which results in the increase of sheath loss and the decrease of permissible current of the power transmission system. While the cable is on operation, because of cable aging and other unexpected reasons, sheath fault always occurs which leads to the further damage of the insulation layer and the life of the cable. These two problems were particularly addressed in this paper. Over last few years, two research groups in South Korea and the United Kingston have worked together extensively to solve these problems and made some great achievements. For tackling the problem of the increase of sheath circulating current, one special device was designed to measure this kind of current; an effective measure was proposed to reduce the current and the new measure was well protected from any further threats like cable fault and lightning. Regarding the problem with sheath fault, one data acquisition system was designed to monitor the sheath fault on field; a new fault phenomenon was discovered for the cable buried in sand; based on the new discovery, the fault was characterised, modelled and simulated; furthermore advanced signal processing techniques were introduced to extract the fault signals from the sheath, detect and locate the fault. These new solutions have either been successfully applied in practical operation of the power cable system or used in further research to propose more advanced solutions. The paper reviewed the latest developments of these new solutions.
Electric Power Systems Research.
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X.H. Wang,
B. Yao,
D.Z. Shen,
Z.Z. Zhang,
B.H. Li,
Z.P. Wei,
Y.M. Lu,
D.X. Zhao,
J.Y. Zhang,
X.W. Fan,
L.X. Guan,
C.X. Cong
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ABSTRACT: A lithium and nitrogen doped p-type ZnO (denoted as ZnO: (Li, N)) film was prepared by RF-magnetron sputtering and post annealing techniques with c-Al2O3 as substrate. Its transmittance was measured to be above 95%. Three dominant emission bands were observed at 3.311, 3.219 and 3.346 eV, respectively, in the 80 K photoluminescence (PL) spectrum of the p-type ZnO:(Li, N), and are attributed to radiative electron transition from conduction band to a LiZn–N complex acceptor level (eFA), radiative recombination of a donor–acceptor pair and recombination of the LiZn–N complex acceptor bound exciton, respectively, based on temperature-dependent and excitation intensity-dependent PL measurement results. The LiZn–N complex acceptor level was estimated to be about 126 meV above the valence band by fitting the eFA data obtained in the temperature-dependent PL spectra.
Solid State Communications.
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ABSTRACT: We have isolated a family of insect-selective neurotoxins from the venom of the Australian funnel-web spider that appear to be good candidates for biopesticide engineering. These peptides, which we have named the Janus-faced atracotoxins (J-ACTXs), each contain 36 or 37 residues, with four disulfide bridges, and they show no homology to any sequences in the protein/DNA databases. The three-dimensional structure of one of these toxins reveals an extremely rare vicinal disulfide bridge that we demonstrate to be critical for insecticidal activity. We propose that J-ACTX comprises an ancestral protein fold that we refer to as the disulfide-directed beta-hairpin.
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ABSTRACT: Confocal Raman microspectroscopy was used to characterize gastric carcinoma cell in both cultured cells and human gastric mucosa tissues. Based on the spectra of single cultured cell, gastric carcinoma cells were screened out in the malignant gastric mucosa successfully and the positive ratio is about 58.06%. The high SNR (signal-to-noise) spectra from human gastric mucosa tissues and cells were obtained by this technique without any sample preparation and the time of detection required less than 3 min. Comparing spectra of malignant gastric mucosa tissues with those of counterpart normal ones, there were obvious spectral changes, including intensity decrease at ∼1587 cm−1 and alteration of peak shape at ∼1660 cm−1 with malignancy. Additionally, spectral features of single cell also differed from those of stomach tissues at ∼1525 and ∼1156 cm−1 where these two bands were assigned to carotenoids. These results demonstrate the possibility of a rapid clinical diagnosis of gastric carcinoma with Raman microspectroscopy in combination with a remote optical probe.
Vibrational Spectroscopy.
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ABSTRACT: The process involved in the development and carcinogenesis of the prostate gland is complex. During early prostate development, the androgenic hormone from embryonic testicles is required for ductal formation, growth, and branching morphogenesis of the prostate gland. From this early stage, interactions between the epithelium and mesenchyme become firmly established through paracrine influence (i.e., growth factors) from mesenchyme (stroma), in response to testosterone, acting on epithelium to stimulate its proliferation, morphogenetic differentiation, and function. In return, the epithelium also exerts its paracrine effects on mesenchyme by regulating the differentiation and specific organizational pattern of its stromal smooth muscle. In a normal adult prostate, the maintenance of normal glandular structure and function is dependent not only on the constant presence of testosterone, but also on a normal intact and stable stroma. This chapter will concentrate first on factors involved in the normal development of the prostate gland and then on the aberrant changes in the homeostatic balance arising either from within (i.e., mutations) or outside (i.e., changes in hormonal balance) that result in derangements of the prostate gland. Finally, environmental and genetic factors that lead to prostate carcinogenesis including activation of oncogenes and mutations of tumor suppressor genes are also discussed.
International Review of Cytology.
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ABSTRACT: The surface properties of coal-pyrite play a major role in determining its separation from coal in processes such as flotation. The solution pH is an important parameter in determining the surface properties of both coal and coal-pyrite such as surface free energy and zeta-potential. In the present investigation, the effect of pH on the surface free energy of pyrites from different sources was studied. The surface free energy of solids is made up of two components, i.e. the dispersive surface free energy and the acid-base interaction energy. Various methods have been used by previous researchers to evaluate these two components for different solids. In the present study, a new approach was developed and used to study the surface free energy of pyrite surfaces. Results indicate that the dispersion surface free energy of various pyrites is independent of pH while the acid-base interaction energy is strongly dependent on the pH. The acid-base interaction energy is different for each pyrite sample and also the change with pH varies with the type of pyrite. Coal-pyrite was found to be more hydrophobic than ore-pyrite which may be attributed to the presence of carbon in coal-pyrites. The acid-base interaction energy varied little with pH for coal pyrites than ore-pyrite. Comparison of acid-base interaction energy with zeta-potential measurements shows a good correlation between the minimum in acid-base interaction energy and the pHpzc.
Minerals Engineering.
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ABSTRACT: Failure analysis of in-service nuclear piping containing defects is an important subject in the nuclear power plants. Considering the uncertainties in various internal operating loadings and external forces, including earthquake and wind, flaw sizes, material fracture toughness and flow stress, this paper presents a probabilistic assessment methodology for in-service nuclear piping containing defects, which is especially designed for programming. A general sampling computation method of the stress intensity factor (SIF), in the form of the relationship between the SIF and the axial force, bending moment and torsion, is adopted in the probabilistic assessment methodology. This relationship has been successfully used in developing the software, Safety Assessment System of In-service Pressure Piping Containing Flaws (SAPP-2003), based on a well-known engineering safety assessment procedure R6. A numerical example is given to show the application of the SAPP-2003 software. The failure probabilities of each defect and the whole piping can be obtained by this software.
Nuclear Engineering and Design.
