Chinese Science Bulletin

Published by Springer Nature

Online ISSN: 1861-9541

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Print ISSN: 1001-6538

Articles


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A novel in vitro angiogenesis model based on a microfluidic device
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November 2011

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139 Reads

Dai Xiaozhen

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Angiogenesis is very important for many physiological and pathological processes. However, the molecular mechanisms of angiogenesis are unclear. To elucidate the molecular mechanisms of angiogenesis and to develop treatments for "angiogenesis- dependent" diseases, it is essential to establish a suitable in vitro angiogenesis model. In this study, we created a novel in vitro angiogenesis model based on a microfluidic device. Our model provides an in vivo-like microenvironment for endothelial cells (ECs) cultures and monitors the response of ECs to changes in their microenvironment in real time. To evaluate the potential of this microfluidic device for researching angiogenesis, the effects of pro-angiogenic factors on ECs proliferation, migration and tube-like structure formation were investigated. Our results showed the proliferation rate of ECs in 3D matrix was significantly promoted by the pro-angiogenic factors (with an increase of 59.12%). With the stimulation of pro-angiogenic factors gradients, ECs directionally migrated into the Matrigel from low concentrations to high concentrations and consequently formed multi-cell chords and tube-like structures. These results suggest that the device can provide a suitable platform for elucidating the mechanisms of angiogenesis and for screening pro-angiogenic or anti-angiogenic drugs for "angiogenesis-dependent" diseases.
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Identification of common microRNA-mRNA regulatory biomodules in human epithelial cancer

November 2010

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103 Reads

The complex regulatory network between microRNAs and gene expression remains unclear domain of active research. We proposed to address in part this complex regulation with a novel approach for the genome-wide identification of biomodules derived from paired microRNA and mRNA profiles, which could reveal correlations associated with a complex network of de-regulation in human cancer. Two published expression datasets for 68 samples with 11 distinct types of epithelial cancers and 21 samples of normal tissues were used, containing microRNA expression (Lu et al. Nature Letters 2005) and gene expression (Ramaswarmy et al. PNAS 2001) profiles, respectively. As results, the microRNA expression used jointly with mRNA expression can provide better classifiers of epithelial cancers against normal epithelial tissue than either dataset alone (p=1×10(-10), F-Test). We identified a combination of six microRNA-mRNA biomodules that optimally classified epithelial cancers from normal epithelial tissue (total accuracy = 93.3%; 95% confidence intervals: 86% - 97%), using penalized logistic regression (PLR) algorithm and three-fold cross-validation. Three of these biomodules are individually sufficient to cluster epithelial cancers from normal tissue using mutual information distance. The biomodules contain 10 distinct microRNAs and 98 distinct genes, including well known tumor markers such as miR-15a, miR-30e, IRAK1, TGFBR2, DUSP16, CDC25B and PDCD2. In addition, there is a significant enrichment (Fisher's exact test p=3×10(-10)) between putative microRNA-target gene pairs reported in five microRNA target databases and the inversely correlated micro-RNA-mRNA pairs in the biomodules. Further, microRNAs and genes in the biomodules were found in abstracts mentioning epithelial cancers (Fisher Exact Test, unadjusted p<0.05). Taken together, these results strongly suggest that the discovered microRNA-mRNA biomodules correspond to regulatory mechanisms common to human epithelial cancer samples. In conclusion, we developed and evaluated a novel comprehensive method to systematically identify, on a genome scale, microRNA-mRNA expression biomodules common to distinct cancers of the same tissue. These biomodules also comprise novel microRNA and genes as well as an imputed regulatory network, which may accelerate the work of cancer biologists as large regulatory maps of cancers can be drawn efficiently for hypothesis generation.

Figure 1. Ultrahigh resolution OCT system using continuum generation in an air-silica microstructure fiber as the light source. MO, microscopic objective lens; BS, beam splitter; D1, D2, detector; λ/2, half-wave plate; A, aperture.  
Figure 2. (a) Typical spectrum of the light source before spectral filtering; (b) Interference fringes recorded by an isolated reflection. The full width at half maximum was measured to be 0.64 μm. Detected optical spectrum (c) and group delay dispersion mismatch of the interferometer arms (d) obtained from the Fourier transform of the interferometric signal (b). The vertical dashed lines mark pronounced spectral features.  
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Ultrahigh resolution optical coherence tomography with femtosecond Ti:sapphire laser and photonic crystal fiber

July 2008

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117 Reads

Optical coherence tomography (OCT) with ultrahigh axial resolution was achieved by the super-continuum generated by coupling femtosecond pulses from a commercial Ti:sapphire laser into an air-silica microstructure fiber. The visible spectrum of the super-continuum from 450 to 700 nm centered at 540 nm can be generated. A free-space axial OCT resolution of 0.64 μm was achieved. The sensitivity of OCT system was 108 dB with incident light power 3 mW at sample, only 7dB below the theoretical limit. Subcellular OCT imaging was also demonstrated, showing great potential for biomedical application.

Network analysis of protein-protein interaction

March 2010

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86 Reads

Residue networks are constructed by defining the residues as the vertices and atom contacts between them as the edges. The residue network of a protein complex is divided into two types of networks, i.e. the hydrophobic and the hydrophilic residue networks. By analyzing the network parameters, it is found that the correct binding complex conformations are of both higher sum of the interface degree values and lower characteristic path length than those incorrect ones. These features reflect that the correct binding complex conformations have better geometric and/or residue type complementarity, and the correct binding modes are very important for preserving the characteristic path lengths of native protein complexes. In addition, two scoring terms are proposed based on the network parameters, in which the characteristics of the entire complex shape and residue type complementarity are taken into account. These network-based scoring terms have also been used in conjunction with other scoring terms, and the new multi-term scoring HPNCscore is devised in this work. It can improve the discrimination of the combined scoring function of RosettaDock more than 12%. This work might enhance our knowledge of the mechanisms of protein-protein interactions and recognition. Keywordsinterface-characteristic path length-residue network-scoring function

Composition dependence of viscosity for Al(1− x )Mgx(0⩽ x ⩽0.10) alloys

June 2007

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32 Reads

Viscosities of molten Al(1−x)Mgx (0⩽x⩽0.10) alloys have been measured in the temperature range of 973 K-1173 K by a torsional oscillation cup method. The viscosity dependence on temperature for Al(1−x)Mgx (0⩽x⩽0.10) melts obeys Arrhenius equation. The viscosity increases with increasing magnesium concentration in the investigated system. There is an important relationship between viscosity and its glass-forming ability for metallic melt.

The electrical conductivity of H2O at 0.21– 4.18 GPa and 20–350°C

June 1997

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79 Reads

The electrical conductivity of H2O in solid and liquid phases has been measured at 0.21–4.18 GPa and 20–350°C. The results indicate: (I) different phases of H2O in solid have different relations between electrical conductivity and temperature and pressure. The conductivity changes continuously with temperature, but discontinuously with the pressure between 2.11 and 2.58 GPa, which corresponds to the transforming pressure between ice (VI) and ice (VII);(II) the amductivity of H2O in liquid all increases with temperature and pressure, but there are discontinuities at pressures between 0.57 and 0.9 GPa, and between 2.11 and 2.58 GPa, which are also consistent with the polyrnorph of ice (ice (V), ice (VI) and ice (VII)). This reflects that H2O in liquid at different pressures has quite different properties of electron chemistry. It is probably the important reason that causes the layers with high electrical conductivity and low velocity in the earth’s ceust and upper mantle.

Design and demonstration of a 0.22 THz gyrotron oscillator

May 2009

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23 Reads

Gyrotrons are the most powerful terahertz sources and have potential applications in many areas. A terahertz gyrotron oscillator with a pulsed solenoid producing up to an 8 T magnetic field has been designed, constructed and tested. In a 7.96 T magnetic field, 3 kW output power radiations at 0.22 THz frequency have been generated.

Ferroelectric phase transition in relaxor ferroelectric single crystals 0.76PMN-0.24PT

April 2012

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27 Reads

The features of the single crystals 0.76PMN-0.24PT in dietectric, ferroetectric, pyroetectric properties and domain structures indicate that they are located between typical ferroetectrics and normal ones. The unpoled crystals present a transitional domain configuration between microdomains and typical macrodomains while the crystals on (001) cuts undergo fietd-induced phase transition under poling, showing two special temperature points Td andT m during the succedent heating procedure. The dietectric constant starts to decrease drastically at Td during cooling, or the transformation from induced macrodomain to transitional domain takes place atT d during heating. Ferroetectric-paraetectric phase transition or depolarization continues within the whole temperature range ofT d-T m, where ferroetectric phase in the form of transitional macrodomains coexists with paraetectric phase. Then the crystals macroscopically transoform into paraetectric phase containing ferroetectric microdomains at a temperature aboveT m. However, owing to the influence of crystallite orientation on fietd-induced phase transition, the temperatureT d does not appear in the same temperature-etectric fietd history in multicrystal ceramics with the same composition as the above single crystals.


Relative paleointensity of the geomagnetic field during the past 0.8 Ma from Nihewan Basin, Hebei Province, China

May 2004

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16 Reads

We conducted a detailed rock magnetic study on upper 80 m of Jing’erwa core from the Nihewan basin. The results indicate that the sediments from Jing’erwa core are suitable for relative paleointensity study, and anhysteretic remanent magnetization (ARM) can be used as the normalization parameter of the natural remanent magnetization (NRM). Our relative paleointensity data of upper 80 m of Jing’erwa core provide a continuous record of the intensity variation during the last 0.8 Ma, which correlates well with the results from marine sediments cores in the Pacific Ocean. This means that the sediments records are reliable for relative paleointensity of Earth’s magnetic field, and suggests that these sediments have recorded the real changes of geomagnetic field, which would provide a new method for regional stratigraphic correlation. KeywordsNihewan basin-earth’s magnetic field-relative paleointensity

A 60 000-year loess-paleosol record of millennial-scale summer monsoon instability from Lanzhou, China

December 1999

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20 Reads

The 28-m high-resolution Shajinping loess section in Lanzhou on the Chinese western Loess Plateau records a detailed history of millennial Asian summer monsoon change since the earlier last glaciation. Summer monsoon proxies of soil magnetic susceptibility, carbonate content and soil color show that Asian summer monsoon experienced a series of rapid episodic pulse enhancements spanning only ca. 1–2 ka and have sub-Milankovitch cycles of progressive weakening in low frequency domain since ca. 60 kaBP. Soil formation responds to these by deepening colors, accumulating organic matter, increasing biological channels and leaching certain carbonates. The pedogenic degree generally increases with the degree of enhancement of summer monsoon. These may reflect the impact of the last glacial fast climatic change in the North Atlantic region on Asian summer monsoon.

Landscape evolution and precipitation changes in the Badain Jaran Desert during the last 30 000 years

June 2000

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33 Reads

On the basis of field expeditions into different parts of the Badain Jaran Desert, new evidence of landscape evolution and precipitation changes during the last 30 000 years has been found from the geomorphological, sedimentological and geochronological studies of the megadune. Different cemented surfaces of palaeo-dunes have been observed in many localities, which are representatives of relatively moister environment. The chronological data show that four periods of more humid environment occurred in the past 30 000 years. The stabilization of dunes in a large scale and the existence of many palaeo-lakes and lacustrine terraces confirm the periodic fluctuations of climate. It implies that the intensity of westerlies and Eastasian monsoons varied in the region of Alashan, and the periods of higher precipitation took place even in the times close to the last glacial maximum.

Variation of summer monsoon intensity on the Loess Plateau of Central China during the last 130 000 a - Evidence from Rb and Sr distribution

March 1997

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24 Reads

THE loess-paleosol sequences from China potentially provide one of the best terrestrial records of past climates. Studies have shown that magnetic susceptibility in the sequences represents a proxy climate index closely related to changes of summer monsoon intensity[ls2]. Some interpretative models have been advanced to account for these magnetic variations, although unanimity of opinion has not been reachedL3]. Recent geochemical studies of chemical weathering on the Loess Plateau by the present authors show that some trace element ratios of the loess to paleosol can reflect the regional climate. Here we present results of Rb/Sr ratio and magnetic susceptibility obtained from the Luochuan loess-paleosol section and have some discussion about the relationships between variation of Rb/Sr ratio and fluctuations of climate. 1 Sampling and analysis The Luochuan loess-paleosol section is located 5 km south of Luochuan City, Shaanxi

Fabrication of metal nanoclusters on graphene grown on Ru(0001)

July 2009

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109 Reads

Monolayer graphene was epitaxially grown on Ru(0001) through exposure of the Ru(0001) to ethylene at room temperature followed by annealing in ultrahigh vacuum at elevated temperatures. The resulting graphene structures were studied by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). The graphene/Ru(0001) surface was used as a periodic template for growth of metal nanoclusters. Highly dispersed Pt clusters with well controlled size and spatial distribution were fabricated on the surface.

First-Principles Investigation on Initial Stage of 2H-SiC(001) Surface Oxidation

May 2009

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167 Reads

We present comprehensive first-principles calculations on the initial stages of SiC oxidation by atomic oxygen on the 2H-SiC(001) surface. In order to study the kinetics of oxygen incorporation at the 2H-SiC(001) surface, we investigated adsorption and diffusion of oxygen atoms and SiO2 nucleation. The adsorption sites, corresponding to the local minima of the potential energy surface (PES) for isolated adatoms, were identified through a comparative study of the adatom binding energy at different locations. We found that the Bridge (siloxane) site is preferred over other adsorption sites. There is no energy barrier at 0K for oxygen insertion into this site. The diffusion energy barriers that the adatom has to overcome when jumping between two adsorption sites were calculated. The premises of silica nucleation were investigated by calculating the modifications of the oxygen atom binding energy due to the interaction with neighboring adatoms.

Two-dimensional gel electrophoresis analysis of the proteomes expressed in the human hepatoma cell line BEL-7404 and normal liver cell line L-02

January 2000

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9 Reads

Proteome analysis technology has been used extensively in conducting discovery research of biology and has become one of the most essential technologies in functional genomics. The proteomes of the human hepatoma cell line BEL-7404 and the normal human liver cell line L-02 have been separated by high resolution two-dimensional gel electrophoresis (2-DE) with immobilized pH gradient isoelectric focusing (IPG-IEF) in the first dimension and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in the second dimension (IPG-DALT). The resulting images have been analyzed using 2-D analysis software. Quantitative analysis reveals that 7 protein spots are detected only in hepatoma BEL-7404 cells, 14 only in L-02 cells, and 78 protein spots show significant fluctuation in quantity in both cell lines (P< 0.01). These protein spots have been displayed on a proteome differential expression map. Analysis for the reproducibility of 2-DE indicates that the positional variability in the IEF dimension is 0.73 mm, while the variability in the SDS-PAGE dimension is 0.44 mm, and the quantitative variability is 17.6%–19.2%. These results suggest that the reproducibility of 2-DE has been suitable for the study of differential expression of proteomes. Proteome differential expression maps can be useful tools for disease diagnosis, drug-target validation analysis and biological process elucidation.

Applying generalized hydrophobicity scale of amino acids to quantitative prediction of human leukocyte antigen-A*0201-restricted cytotoxic T lymphocyte epitope

January 2006

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11 Reads

Derived from 149 hydrophobic factors of 20 natural amino acids, a novel amino acid descriptor termed as generalized hydrophobicity scale (GH-scale) was proposed by principal component analysis (PCA). Via genetic algorithm-partial least square (GPLS) method, quantitative structure-activity relationship (QSAR) model was constructed by GH-scale for 152 human leukocyte antigen (HLA)-A*0201-restricted cytotoxic T lymphocyte (CTL) epitopes with the model estimated and cross-validated correlative coefficients of R 2 = 0.813 and Q 2 = 0.725, respectively. It was indicated that hydrophobic interaction played an important role in HLA-A*0201-CTL interaction, prominently at anchor residues.

Figure 1 Daily water discharge in 2005 at the Gaoyao Hydrometric Station of the Xijiang River. + Marks sampling date; arrow indicates the box alloca- tion range of the sample value; ×, daily mean TSS value in the corresponding date. “Flood” marks the period of the event from June 21 ― 28, the bar un- derneath marks the sampling period on the flood. 
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The impacts of ‘05.6’ extreme flood event on riverine carbon fluxes in Xijiang River

March 2007

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607 Reads

An extreme flood event with a frequency of nearly 200 year occurred in June of 2005 in the Xijiang River, the main trunk stream of the Zhujiang River. Samples were systematically collected during the flood event, and water quality parameters, including total suspended sediment (TSS), dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC) were analyzed, and riverine carbon concentrations associated with its changing pattern through the flood process were discussed. These parameters reflect the changes in basin surface flow and subsurface flow during the flood. This flood event influenced annual flux estimations of POC, DOC, and DIC to great extents. Based on carbon flux estimations for the year 2005 and the flood event (June 21–28) in the Xijiang River, it was found that DIC, DOC, and POC fluxes during ‘05.6’ flood event are 1.52×106 g.km−2.a−1, 0.24×106 g.km−2.a−1, and 0.54×106 g.km−2.a−1, and account for 14.87%, 24.75% and 44.89% of the annual fluxes in 2005, respectively. The results suggested that carbon exports during extreme flood events had great contributions to the total carbon fluxes and composition of various carbon components, being important for accurate estimates of annual carbon fluxes in rivers with frequent floods.

Coordination polymer based on (1,2-bis(2-picolinamido) phenyl)copper

January 2005

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10 Reads

(1,2-bis(2-pyridinecarboxamido)benzene copper Cu(bpb) was synthesized and employed as a building block to construct supramolecular coordination polymer based on intermolecular coordination and hydrogen bonding interactions. X-ray single-crystal diffraction characterization revealed that intermolecular coordination interactions lead to the formation of one-dimensional infinite molecular columns, which array along the same direction in the crystal resulting in the three-dimensional network. The molecular columns are linked together by hydrogen-bonding interactions, which infinitely extend inbc plane. The one-dimensional coordination bonding and two-dimensional hydrogen-bonding interactions result in the formation of supramolecular coordination polymer.

Mechanisms of sodium and potassium ions transfer facilitated by dibenzo-15-crown-5 across the water /1,2-dichloroethane interface using micropipettes

August 2002

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43 Reads

The transfer of sodium and potassium ions facilitated by dibenzo-15-crown-5 (DB15C5) has been studied at the micro-water/1,2-dichloroethane (water/DCE) interface supported at the tip of a micropipette. Cyclic voltammetric measurements were performed in two limiting conditions: the bulk concentration of Na+ or K+ in the aqueous phase is much higher than that of DB15C5 in the organic phase (DB15C5 diffusion controlled process) and the reverse condition (metal ion diffusion controlled process). The mechanisms of the facilitated Na+ transfer by DB15C5 are both transfer by interfacial complexation (TIC) with 1:1 stoichiometry under these two conditions, and the corresponding association constants were determined at log β1 = 8.97 ±0.05 or log β1 = 8.63 ±0.03. However, the transfers of K+ facilitated by DB15C5 show different behavior. In the former case it is a TIC process and its stoichiometry is 1:2, whereas in the latter case two peaks during the forward scan were observed, the first of which was confirmed as the formation of K+(DB15C5)2 at the interface by a TIC mechanism, while the second one may be another TIC process with 1:1 stoichiometry in the more positive potential. The relevant association constants calculated for the complexed ion, K+(DB15C5)2, in the organic phase in two cases, logβ2, are 13.64 ±0.03 and 11.34 ±0.24, respectively.

Study of ionizable drugs transfer across the water/ 1,2-dichloroethane interface with phase volume ratio equal to unity using a three-electrode system

June 2003

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29 Reads

The electrochemical behavior of ionizable drugs (Amitriptyline, Diphenhydramine and Trihexyphenedyl) at the water/1,2-dichloroethane interface with the phase volume ratio (r = V o/Vw) equal to 1 are investigated by cyclic voltammetry. The system is composed of an aqueous droplet supported at an Ag/AgCl disk electrode and it was covered with an organic solution. In this manner, a conventional three-electrode potentiostat can be used to study the ionizable drugs transfer process at a liquid/liquid interface. Physicochemical parameters such as the formal transfer potential, the Gibbs energy of transfer and the standard partition coefficients of the ionized forms of these drugs can be evaluated from cyclic voltammograms obtained. The obtained results have been summarized in ionic partition diagrams, which are a useful tool for predicting and interpreting the transfer mechanisms of ionizable drugs at the liquid/liquid interfaces and biological membranes. Keywordswater/1,2-dichloroethane interface-ionizable drug transfer-three-electrode system-phase volume ratio-ionic partition diagram

One pot cascade synthesis of substituted 1,2,4-triazol-3-ones

September 2010

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37 Reads

Substituted triazolinones were prepared by a three-component reaction of aldehydes, hydrazines and azodicarboxylates using TFA as a catalyst. The procedure was convenient and efficient, utilizing readily available substrates. A plausible mechanism for the cascade process is proposed. Keywordstriazolinones-cascade reactions-multicomponent reactions (MCRs)-azodicarboxylates

AM1 computational study on metabolites of 1,3-butadiene interstrand cross-linking DNA

April 2012

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7 Reads

The alkylating reactions of 1,2-epoxy-3,4-butene (EB) and 1,2,3,4-diepoxybutane (DEB) —the important metabolites of rodent carcinogenic 1,3-butadiene, with adenine and cytosine and interaction with fragment of DNA on major groove—have been computed. Results show that there are little differences in activation energy between EB and DEB, so it is difficult to explain the fact that the mutagenicity of DEB is greater (about 100-fold) than that of EB by the ability of alkylation. It is also known that DEB can interstrand cross-link with DNA through two times alkylating reactions, whereas EB cannot. So this may contribute to the significant different genotoxicity of the two agents. Meanwhile, DEB can interstrand cross-link with many sequences of DNA in major groove vs. two in minor groove, which increases opportunity of interstrand cross-link with DNA in major groove. This difference may be the reason of base selection of DEB mutation. The deformation of some cross-linked DNA may also contribute to this selection to some degree.

Production of ?-1,3-glucanase and chitinase of two biocontrol agents and their possible modes of action

February 2002

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160 Reads

Pichia membranefaciens Hansen and Candida guilliermondii (Cast) Langeronet Guerra are two antagonists of R. stolonifer on harvested nectarine and peach fruits. In this study, β-1,3-glucanase and chitinase activities of the antagonists were induced in vitro and in vivo. The highest β-1, 3-glucanase activity was detected in Lilly-Barnett minimal salt medium supplemented with glucose in combination with CWP of R. stolonifer as a carbon source. The β-1,3-glucanase activity of P. membranefaciens reached the maximum level, being 114.0 SU (specific activity unit), and that of C. guilliermondii reached 103.2 SU. The lowest β-1,3-glucanase activity was observed in the medium containing glucose as sole carbon source. P. membranefaciens was able to produce significantly higher levels of chitinase (exochitinase and endochitinase) in vitro than C. guilliermondii grown in Czapeck minimal medium. An increase in β-1,3-glucanase and chitinase activity was also triggered by wounding, adding of carbon sources and yeast cells. The results showed that both β-1,3-glucanase and chitinase from P. membranefaciens and C. guilliermondii exhibited some effects on controlling R. stolonifer, and might have a synergistic activity against R. stolonifer.

The adsorption of 2,5-dimer-capto-1,3,4-thiadiazole (DMTD) on copper surface and its binding behavior

March 2001

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97 Reads

The interaction mechanism of 2,5-dimercapto-1,3,4-thiadiazole (DMTD) on copper surface was studied by surface-enhanced Raman scattering (SERS), infrared (IR) and X-ray photoelectron spectroscopy (XPS) techniques. The SERS spectra were obtained. We found that DMTD bound with the copper via its two-excocyclic mercapto groups. The monosulphide salt was formed. At the same time, DMTD coordinated with the Cu+ ion through the excocyclic mercapto groups and polymerized via the Cu+ ion into a onedimensional polymer chain on the copper surface. Keywords2,5-dimercapto-1,3,4-thiadiazole (DMTD)-surface-enhanced Raman scattering (SERS)-adsorption and binding

Photooxidation of Hantzsch 1,4-dihydropyridines by molecular oxygen

September 2010

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68 Reads

Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP, 1a–1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies demonstrate that photoinduced singlet electron transfer from 1,4-DHP to molecular oxygen occurs. The generated superoxide radical anion (O2 −·) is responsible for this typical photochemical oxidation. KeywordsHantzsch 1,4-dihydropyridines-molecular oxygen-photoinduced electron transfer-superoxide (O2 −·)

Sorption and desorption of 1,4-dichlorobenzene on peat

March 2000

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13 Reads

Sorption and desorption of 1,4-dichlorobenzene (DCB) on peat (> 92% organic matter) display large-scale hysteresis and nonlinearity. The magnitude of desorption hysteresis decreases in the order: untreated Pahokee peat (P)> acid treated peat (FP)> humin (TP). The desorption percentages are lower than 28% of the sorbed 1, 4-DCB after desorbing for 6 days. The sorption and desorption isotherms are well fitted to Freundlich equation, whose parameter 1/n ranges from 0.055 to 0.527. Moreover, the parameter 1/n of the desorption isotherm is significantly lower than that of the sorption isotherm, but the parameter logK increases on contrary to 1/n. The desorption isotherms are very well fitted to Langmuir equation, whose Qm decreases in the order: TP> FP> P. The apparent partition coefficients (K P) increase with increasing sorption time or decreasing aqueous equilibrium concentration of DCB. AndK P of P is significantly higher than that of FP or TP.

Characterization of an endo-1,4-β-glucanase from Lilium longiflorum that functioned in pollen germination and pollen tube growth

March 2008

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46 Reads

Endo-β-glucanases play vital roles in the regulation of pollen tube growth. Here, a previously identified endo-1,4-β-glucanase from Lilium longiflorum (lily), named LlpCel1, was expressed in Escherichia coli, purified, and further investigated for its physiological function. The recombinant LlpCel1 protein hydrolyzed carboxy-methylcellulose (CMC) and exhibited activity towards laminarin from Eisenia. arborea and 1,3:1,4-β-glucan of barley. The pH for the optimum activity was 6.0 and the value of K m calculated from CMC was 5.0 mg/mL. Adding EDTA resulted in the total loss of the enzymatic activity, and this effect could be restored by the addition of Ca2+. Western blotting analysis showed that LlpCel1 protein was present in pollen grains and rehydrated pollen grains, and the amount of the protein was increased during pollen germinating, but not in the pollen tube. Consistently, the immunofluorescence labeling study with the antibody against LlpCel1 also indicated the presence of LlpCel1 at the beginning of germination, but not in the elongating pollen tube. Furthermore, incubation of LlpCel1 with pollen at the beginning of pollen germination increased the germination percentage and the length of pollen tube. All of these results suggested that LlpCel1 could play an important role in the regulation of lily pollen germination and the initiation of pollen tube growth.

Synthesis of novel chiral bisoxazoline ligands with a spiro[4,4]-1,6-nonadiene skeleton

September 2010

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31 Reads

A new type of chiral bisoxazoline ligands 1 based on spiro[4,4]-1,6-nonadiene backbone was easily prepared in six steps from racemic spiro[4,4]-nonane-1,6-dione, with the Pd-catalyzed coupling of the enol triflates with CO and amino alcohols as the key steps for the construction of the oxazoline moiety. The structure of the ligand (R,S,S)-1b was unambiguously established by X-ray crystallographic analysis. The chiral Cu(II) complex generated in situ from the combination of spiro bisoxazoline ligand (S,S,S)-1c and Cu(OTf)2 was effective in the catalysis of asymmetric chlorination of the β-ketoester, methyl 1-oxo-2,3-dihydro-1H- indene-2-carboxylate, affording the corresponding chlorinated derivative in 99% yield with 17% ee. Keywordsspiro ligand-bisoxazoline-asymmetric chlorination-β-ketoester

Synthesis and optical properties of poly[(4-(benzoxazole-2-yl)phenyl)methyl methacrylate] with 1,8-naphthalimide end group

January 2009

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32 Reads

A series of homopolymers, poly[(4-(benzoxazole-2-yl)phenyl)methyl methacrylate] (NAPH-PMABEs) containing benzoxazole side chain and 1,8-naphthalimide end group, were prepared by atom transfer radical polymerization (ATRP) and end-group modification. The structure of NAPH-PMABE was characterized by GPC, 1H-NMR and UV-vis spectra. The polymer has good solubility in common organic solvents, such as dichloromethane (CH2Cl2), tetrahydrofuran (THF), N,N-dimethylformamide (DMF), chloroform (CHCl3), acetone and toluene. The optical properties of NAPH-PMABE were investigated. Results show that NAPH-PMABE has a composite emission spectrum comprising an ultraviolet component originating from benzoxazole side chains and a green component originating from 1,8-naphthalimide end group in both solution and film. The intensity of the two emission bands can be easily tuned by changing molecular weight.

Simulation of 1991–2005 Meiyu seasons in the Yangtze-Huaihe region using BCC_RegCM 1.0

April 2010

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21 Reads

By using BCC_RegCM 1.0 (RegCM for short) from Beijing Climate Center (BCC), China Meteorological Administration (CMA), the Meiyu season characters over the Yangtze-Huaihe region during 1991–2005 are simulated. The major conclusions of this study may be summarized as the following: (1) RegCM can reproduce the interannual variation and the spatial distribution of the summertime precipitation and temperature in the Yangtze-Huaihe region. (2) By use of a generalized Meiyu criterion and in accordance with model-calculated precipitation and temperature, the Meiyu onset and ending date have been determined. Compared with the observation, RegCM can simulate the interannual variation of the Yangtze-Huaihe Meiyu with preferable capability for most of the normal Meiyu years (such as 1995, 1997, 2000, 2001, 2002 and 2004), especially for the rich Meiyu years of 1996, 1998 and 1999. (3) In terms of the average simulation for the recent 15 years, the timings of onset and ending of Meiyu occur on June 1 and July 13, respectively, which are earlier than the climatological observation. For duration, Meiyu persists for 32 d, 3 d shorter than the observation. The index of Meiyu intensity is 2.45, while the climatological one is 3.00. Therefore, RegCM is capable of simulating the climatological Meiyu duration and intensity, while the capability of simulating the onset and ending date of Meiyu still needs to be improved. Keywordsregional climate model-Meiyu in Yangtze-Huaihe region-Meiyu onset-Meiyu ending-Meiyu rainfall

Sub-10 fs laser pulses with repetition rate of 1.1 GHz by a Ti: Sapphire oscillator

October 2009

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31 Reads

We demonstrate a compact Ti: sapphire oscillator with ring cavity configuration. By optimizing the intracavity dispersion with chirped mirrors, pulses with repetition rate of 1.1 GHz are coupled out by the uncoated wedges in the cavity. Under 7W CW pump laser centered at 532 nm, the average power of the output pulses is about 30 mW, the duration is less than 10fs and the spectrum spans from 670 nm to 920 nm.

Radiolarian record to paleoecological environment change events over the past 1.2 MaBP in the southern South China Sea

September 2002

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22 Reads

This note studies the Radiolarian fossil groups since 1.2 MaBP in ODP leg 184 site 1143, the southern South China Sea (SCS). The result shows that radiolarian abundance experienced a significant variation: before 0.9 MaBP it remained at the extremely low level, but increased with low extent between 0.9–0.65 Ma, which corresponded to the Mid-Pleistocene Transition stage, and it increased rapidly after 0.65 MaBP. During the whole process, the average abundance became higher and higher in each stage, and showed regularly periodic fluctuations. The obvious increase after 0.65 MaBP is inferred to result from the enhanced upwelling in this region, which was induced by the intensified monsoon circulation after the “Mid-Pleistocene Transition”. An outstanding result of the spectral analyses is that a long oscillation of ∼ 0.2 Ma cycle was found in the records of radiolarian abundance and complex diversity, which corresponds well to the result of other paleoceanographic indexes. This probably indicated a special cycle characteristic of paleoecological environment evolution in this area. In addition, all of the radiolarian indexes show an obvious boundary in about 0.47 MaBP, indicating the abrupt variation of the community structure and radiolarian abundance level before and after 0.47 MaBP. So we suppose that there existed a distinct change event of oceanic ecology environment during that period.

Single- and multiple-scattering properties of ice crystals in 1.38 μm wavelength and its potential applications in satellite remote sensing

April 1999

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9 Reads

An improved ray-optics theory and Mie theory for single scattering and the adding-doubling method for multiple scattering are used to study the relationship between the radiation in the wavelengths of 1.38, 3.979, 6.5, and 11.03 μm and the microphysics of cirrus clouds. It is shown that the strong 1.38 μm water vapor band in the near-IR region is superior to the other three IR channels used in current operational satellites and has potential possibility of remote sensing of microphysical and optical properties of cirrus clouds. Keywordsice crystals single scattering-multiple scattering-remote sensing channel

An experimental study of dehydration melting of phengite-bearing eclogite at 1.5–3.0 GPa

June 2009

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70 Reads

Dehydration melting experiments were performed on ultrahigh-pressure eclogite from Bixiling in the Dabie orogen at 1.5–3.0 GPa and 800–950°C using piston cylinder apparatus. The results show that (1) eclogite with ∼5% phengite started to melt at T⩽800–850°C and P = 1.5–2.0 GPa and produced about 3% granitic melt; (2) the products of dehydration melting of phengite-bearing eclogite vary with temperature and pressure. Fluid released from dehydration of phengite and zoisite leads to partial melting of eclogite and formation of plagioclase reaction rim around kyanite at pressures of 1.5–2.0 GPa and temperatures of 800–850°C; (3) phengite reacted with omphacite and quartz and produced oligoclase, kyanite and melt at elevated temperatures. Oligoclase is the primary reaction product produced by partial melting of phengite in the eclogite; and (4) the dehydration melting of phengite-bearing eclogite at pressures of 1.5–3.0 GPa and temperatures ⩾900°C results in formation of garnets with higher molar fraction of pyrope (37.67 wt.%–45.94 wt.%). Potassium feldspar and jadeite occur at P = 2.4–3.0 GPa and T⩾900°C, indicating higher pressure and fluid-absent conditions. Our results constrain the solidus for dehydration melting of phengite-bearing eclogite at pressures of 1.5–3.0 GPa. Combining experimental results with field observations of partial melting in natural eclogites, we concluded that phengite-bearing eclogites from the Dabie-Sulu orogen were able to partially molten at P = 1.5–2.0 GPa and T = 800–850°C during exhumation. The ultrahigh-high pressure eclogites would have experienced partial melting in association with metamorphic phase transformation under different fluid conditions.

A 1.5 Ma sporopollen record of paleoecologic environment evolution in the central Chinese Loess Plateau

February 2004

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47 Reads

A 1.5 Ma sporopollen record was obtained from a continuous loess-paleosol sequence at Chaona in the central Chinese Loess Plateau. It shows that (1) arid herbs of largelyArtemisia and Chenopodiaceae and arbors of mainlyPinus, Betula andQuercus dominate loess and paleosol, respectively, reflecting cycles of cold-dry and warm-humid conditions of glaciation and interglaciation; (2) that similar vegetation pattern and cold-dry condition were found in times of unusual thick and coarse loesses L9 and L15, which have been regarded as two extremely cold and dry times as indicated by inorganic climatic proxies; and (3) that shifts of vegetations from earlier forest-steppe to open-forest and steppe and then to steppe were found at 0.95 and 0.5 Ma, implying a stepwise of drying of the Loess Plateau in the Quaternary. KeywordsChinese Loess Plateau-loess-paleosol-sporopollen-ecological environment change

Deep sea pollen record during 12–1.6 Ma from the southern South China Sea and its response to environmental change

August 2007

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29 Reads

Based on deep-sea pollen results (512–76 m) from ODP Site 1143 in the southern South China Sea (SCS), the climate and vegetation evolution sequence on the surrounding islands and the exposed continental shelf are discussed. The pollen records show that the pollen influx was quite low before 8.15 Ma and increased dramatically afterwards. The influx changes can be ascribed, on one side, to tectonics deformations around the southern SCS resulting in rapid uplift of islands and subsequent increase of the sediment rates and pollen influx and on the other side to climate cooling and monsoon enhancement. Around 2.63 Ma was another obvious boundary, the increasing of pollen and spores influx since this time was mainly related to global climate cooling. Spectrum analysis of pollen influx values shows that 2 Ma, 0.67 Ma, and 0.19–0.17 Ma cycles existed during 12–3.0 Ma, while 0.1 Ma and 46.9 ka cycles existed during 3.0–2.0 Ma.

Figure 1 Schematic map showing the locations of ODP Site 1146 and two reference sections of Chinese Loess, and the current pattern of the East Asian monsoon.
Table 1 Loads of major elements in carbonate-free sediments taken from ODP Site 1146 for each factor
Evolution of the East Asian monsoon and its response to uplift of the Tibetan Plateau since 1.8 Ma recorded by major elements in sediments of the South China Sea

February 2011

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90 Reads

Evolution of the East Asian monsoon and its response to uplift of the Tibetan Plateau has been investigated in the study of global change. Core sediment samples drilled in the South China Sea during ODP Leg184 are the best materials for studying long-term variability of the East Asian monsoon. R-mode factor analysis of major elements in the fine grain-sized carbonate-free sediments (<4 μm) of the upper 185 mcd splice of ODP Site 1146 drilled during Leg184 in the South China Sea shows that Ti, TFe2O3, MgO, K2O, P, CaO, and Al2O3 are representative of a terrestrial factor. The variation in the terrestrial factor score is subject to chemical erosion in the source region and thus indicates the evolution of the East Asian summer monsoon. The terrestrial factor score has three stepwise decreases at ∼1.3 Ma, ∼0.9 Ma, and ∼0.6 Ma, indicating the phased weakening of the East Asian summer monsoon is related to wholly stepwise, quick uplifts of the Tibetan Plateau since 1.8 Ma. The periodic fluctuation of the terrestrial factor score since ∼0.6 Ma indicates that the glacial-interglacial cycles have been the main force driving the evolution of the East Asian monsoon. As in the case of Chinese loess, the long-term evolution of the East Asian monsoon recorded in sediments of the South China Sea reflects a coupled effect of the glacial-interglacial cycle and uplift of the Tibetan Plateau. Keywordsmajor element–chemical erosion–glacial-interglacial cycle–uplift of Tibetan Plateau–evolution of the East Asian monsoon

The recognizing of ca. 1.95 Ga tectono-thermal eventin Kongling nucleus and its significance for the evolution of Yangtze Block, South China

February 2001

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28 Reads

Some 1.95 Ga metamorphism of high-grade Archean rocks in Kongling terrain, continental nucleus of Yangtze Block, South China, are recognized by Sm-Nd dating. This event is further confirmed by the ages of single zircon SHRIMP U-Pb and K-Ar analyses of TTG and (or) paragneisses, and intrusions of potassic-granitic batholith in the region. The coincidence in period between the high-grade metamorphism in the Kongling area and the creation of major basement rocks of its neighborhoods of the Yangtze Block around the Kongling Archean nucleus makes it a favorable explanation for their tectonic connections that, in the whole Yangtze Block there was some tectono-thermal event of ca. 2.0-1.8 Ga, which resulted in the formation of unitive Yangtze basement. KeywordsKongling high-grade metamorphic terrain-tectonothermal event-Paleoproterozoic-unitive basement

Structural stability of C60 films under the bombardment of 1.95 GeV Kr ions

November 2010

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16 Reads

The structural stability of C60 films under the bombardment of 1.95 GeV Kr ions is investigated. The irradiated C60 films were analyzed by Fourier Transform Infrared (FTIR) spectroscopy and Raman scattering technique. The analytical results indicate that the irradiation induced a decrease of icosahedral symmetry of C60 molecule and damage of C60 films; different vibration modes of C60 molecule have different irradiation sensitivities; the mean efficient damage radius obtained from experimental data is about 1.47 nm, which is in good agreement with thermal spike model prediction. Keywords1.95 GeV Kr ions-C60 films-structural stability-efficient damage radius-thermal spike model

Record of environmental change by α-cellulose δ13C of sphagnum peat at Shennongjia, 4000–1000 aBP

October 2009

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28 Reads

The Dajiuhu Basin at Shennongjia, located within typical East Asian Monsoon region, preserves a sub-alpine sphagnum peat deposition in its central area. The topmost 120 cm of the peat covers the last 4000 years according to AMS 14C dating of pollen concentration. Carbon isotope of α-cellulose, extracted from sphagnum peat, provides a quantitative reconstruction of atmospheric relative humidity, based on transfer functions of C3 plants carbon isotopic fractionation equation and the bryophyte photosynthesis CO2 absorption rate equation. δ 13C, TOC and C/N variations reveal that the Dajiuhu area has experienced a long-term tendency to dry during 4000–1000 aBP, with a major transition happening around 3000 aBP. Four relative dry events are identified at 3400–3200, 3000–2600, 2200–2000 and 1600–1400 aBP, respectively, corresponding to those climate events documented in many global records. Three periodicities, 664 a, 302 a and 277 a enclosed in the atmospheric humidity of Dajiuhu are correlated to the cycles of solar activities. The weakening of East Asia summer monsoon during this period registered in the Dajiuhu peat is consistent with the synchronous weakening of Indian Monsoon. This trend may be attributed to gradual decrease of Northern Hemispheric summer solar insolation and the consequently southward migration of Intertropical Convergent Zone (ITCZ).

Groundwater recharge and climatic change during the last 1000 years from unsaturated zone of SE Badain Jaran Desert

July 2003

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33 Reads

The history of groundwater recharge and climatic changes during the last 1000 years has been estimated and reconstructed using environmental chloride from unsaturated zone profile in the southeast Badain Jaran Desert, NW China. By using a steady-state model for duplicate unsaturated zone chloride profiles, the long-term recharge at the site was estimated to be 1.3 mm yr−. From one profile, which reached the water table, the climatic change events of 10–20 years duration were well preserved. There were 3 wet phases and 4 dry episodes during the recent 800 years according to the peaks and troughs of recharge rate calculated via chloride concentration and moisture content. There was a dry episode before 1290 AD. At ca. 1500–1530 AD, which is an important date, there was an abrupt change from drought to wet conditions. At the beginning of the 1800s, local climate changed from wet to dry occurred and subsequently deteriorated over the past 200 years. The unsaturated profile was compared with the Guliya ice core records. The agreement of wet and dry phases from 1200 to 1900 AD is quite good, whilst trends diverged during the last 100 years. It seems that the large-scale climate difference took place between mountain regions and the desert basin in NW China during the 20th century, which closely correspond to the water table reduction of some 1 metre.

A 1000-year chironomid-based salinity reconstruction from varved sediments of Sugan Lake, Qaidam Basin, arid Northwest China, and its palaeoclimatic significance

October 2009

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418 Reads

A 1000-year high-resolution (∼10 years) chironomid record from varved sediments of Sugan Lake, Qaidam Basin on the northern Tibetan Plateau, is presented. The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus, and the relatively low-saline-water taxa Procladius and Psectrocladius sordidellus-type. Variations in the chironomid fauna and inferred salinities suggest that over the last millennium, the Sugan Lake catchment has alternated between contrasting climatic conditions, having a dry climate during the period 990–1550 AD, a relatively humid climate during the Little Ice Age (LIA) (1550–1840 AD), and a dry climate again from 1840 AD onwards. At the decadal to centennial scale, a wet event around 1200–1230 AD, interrupting the generally arid period (990–1550 AD), and a dry event around 1590–1700 AD, punctuating the generally humid period (1550–1840 AD), are clearly documented. Trends in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher frequency. The effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China (ANC). The LIA, characterized by generally humid conditions over the westerly-dominated ANC was distinctly different from that in monsoonal China, implying an “out-of-phase” relationship between moisture evolution in these two regions during the past 1000 years.

Reconstruction of temperature series of China for the last 1000 years

December 2007

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982 Reads

This paper reports a study on reconstructing temperature series for ten regions of China over the last 1000 years with a time resolution of 10 a. The regions concerned are: Northeast, North, East, South China, Taiwan, Central, Southwest, Northwest China, Xinjiang and Qinghai-Tibet Plateau. A variety of proxy data, such as ice core, tree-rings, stalagmites, peat, lake sediments, pollen and historical records, were validated with instrumental observations made in the last 120 years, and applied in the reconstruction of the temperature series. A temperature series for whole China is then established by averaging the ten regional series with a weighting proportional to the area of each region. Finally, temperature variations for the last 1000 years are examined, with special focus placed on the characteristics of the Medieval Warm Period (MWP), the Little Ice Age (LIA), and Modern Warming (MW).

Reconstruction of the past 1000-a temperature in Canada based on pollen data

September 2002

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15 Reads

Reconstructions of past climate based on pollen data have formed a robust approach and produced a great of products in time scales from a millennium to ten millenniums. However, it is an attempt for reconstruction of the past decade-century climate in the Global Change field. This note reports a reconstruction of the past 1000-a temperature in a 50-a scale in Canada based on pollen data. Because there were little human activities during the last 1000 years in North America, the climate in the period mainly responded to natural changes. The reconstruction of a natural-forcing change in the climate can provide a basis to recognize the climate changes impacted from human activities in China. The technique of modern analogue can be implemented to reconstruct the past millennium climate in China.

Relationship between Earth-Sun-Moon 1000 Ma ago: Evidence from the stromatolites

November 2004

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62 Reads

The studies on stromatolites occurring in the Mesoproterozoic Tieling Formation, Zhoukoudian, Beijing indicate that the thickness of bright-dark lamina pairs in the stromatolites shows periodic variations, which are interpreted as monthly and seasonal rhythms. On the basis of the S-shaped stromatolites, some preliminary paleo-astronomic parameters have been obtained as follows: In the late Mesoproterozoic (1000 Ma ago) there were at least 516±20 d, 12.9 ±0.5 months per year, 40 d per month and at most 16.99 ± 0.66 h per day, and paleo-obliquity of the ecliptic was 29.2°-30.6°.

Exogenous cAMP upregulates the expression of glnII and glnK-amtB genes in Sinorhizobium meliloti 1021

August 2006

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23 Reads

The existence of multiple adenylate cyclase encoding genes implies the importance of cAMP in Sinorhizobium meliloti 1021. In this study, as a pioneer step of understanding cAMP roles, microarray analysis on S. meliloti was carried out for the function of exogenous cAMP. To our surprise, the result showed that the transcriptions of glnII and glnK genes were significantly upshifted in the presence of exogenous cAMP in S. meliloti. This phenomenon is further confirmed in S. meliloti that the expression of either glnII or glnK promoter-lacZ translational fusion is higher in the presence of exogenous cAMP. Therefore, for the first time, we have identified genes from S. meliloti whose expression is activated by cAMP. The potential physiological role of upregulation of glnII and glnK by cAMP is discussed.

Dosimetric parameters of palladium-103 brachytherapy source with Monte Carlo simulation

May 2008

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34 Reads

Before clinical application of a new source, the dosimetric parameters of the source should be accurately determined. This work is dedicated to the Monte Carlo method to calculate dosimetric parameters as recommended by the American Association of Physicists in Medicine (AAPM) TG-43 guidelines for model ADVANTAGE™ palladium-103 source and, through comparison with data from another published report for the same source, presents a suggested dataset for clinical applications. From these calculations, tables are presented for the radial dose function and the anisotropy function of palladium-103 brachytherapy source. The dose rate constants are found to be 0.671 (cGyh-1U-1) in liquid water and 0.673 (cGyh-1U-1) in Solid Water™. And the anisotropy constants in liquid water and Solid Water™ are found to be 0.864 and 0.865 respectively. Comparison with the previous study shows that our results of dosimetric parameters are in good agreement with those measured and calculated by Meigooni et al. (2006) both in Water and Solid Water™.

Influence of PrP 106–126 on expression of laminin and fibronectin in astrocyte

July 2008

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10 Reads

Astrogliosis is a hallmark of prion disease, but the metabolic alterations of astrocytes remain poorly documented. A synthetic peptide corresponding to amino acid 106–126 of the human prion protein (PrP) has been shown to be toxic to neurons. In this study, the effects of PrP 106–126 on astrocytes were investigated in vitro. The proliferation of astrocytes was significantly (P < 0.05) increased when grown in media conditioned with PrP 106–126 (80 μmol/L) from microglia. The expression of laminin (LN) and fibronectin (FN) was examined at both mRNA and protein levels. The results showed that exposure of astrocytes to PrP 106–126 enhanced the expression of LN and FN. The increase of FN in astrocyte cultures required cytokines previously released by activated microglia. This study reveals the expression of LN and FN affected by PrP106–126.

Table 1 10 Be and 10 Be/ 7 Be at WLG and at other sites
10Be/7Be implies the contribution of stratosphere-troposphere transport to the winter-spring surface O3 variation observed on the Tibetan Plateau

January 2011

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97 Reads

10Be/7Be is a stratospheric sensitive tracer. In this paper, measurements of 10Be/7Be and surface O3 from October 2005 to May 2006 at Mt. Waliguan (hereafter WLG, 100.898°E, 39.287°N, 3810 m, a.s.l.), China global atmospheric watch (GAW) observatory, are introduced and used to investigate the stratosphere-troposphere transport (STT) and its impact on surface O3 on the Tibetan Plateau. The results show that the magnitude of STT is weak in winter, followed by strengthening from the end of winter to the middle of spring (from mid February to mid April) with large increases in 10Be,7Be,10Be/7Be and surface O3. At the end of spring (from the end of April to mid May in this paper), the STT weakened, and the continuous increase of surface O3 at WLG is produced by tropospheric photochemistry reactions. Keywords 10Be/7Be–stratosphere-troposphere transport–surface O3 –Mt. Waliguan