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Search Results: 1 - 10 of 34568 matches for " Jilin Zhou "
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Precise identification of photosynthetic glycerolipids in microalga Tetraselmis chuii by UPLC-ESI-Q-TOF-MS
HaiYing Li,XiaoJun Yan,JiLin Xu,ChengXu Zhou
Science China Life Sciences , 2008, DOI: 10.1007/s11427-008-0138-1
Abstract: Precise structural identification of photosynthetic polar glycerolipids in microalga Tetraselmis chuii has been established using Ultra Performance Liquid Chromatography-Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry (UPLC-ESI-Q-TOF-MS) by direct analysis of the total lipids extract. The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in both positive and negative modes. The structural determination was based on the characteristic product ions yielded by different glycerolipids under ESI-MS/MS mode, and confirmed the molecular species by the carboxylate anions produced by glycerolipids in the negative mode. As a result, more than 40 lipid molecular species, including 11 monogalactosyldiacylglycerols (MGDG), 7 digalactosyldiacylglycerols (DGDG), 16 sulfoquinovosyldiacylglycerols (SQDG), and 9 phosphatidylglycerols (PG), were detected in Tetraselmis chuii, which had never been identified before in this microalga. Furthermore, some intact lipid molecules with hydroxylated fatty acids that could not be detected by the traditional GC-MS method were found this time, providing novel information for the photosynthetic lipidome of Tetraselmis chuii. Comparative studies on fatty acids at the sn-2 position showed that SQDG and MGDG are dominantly biosynthesized through the prokaryotic pathway, PG is a typically mixed biosynthetic pathway, while DGDG is somewhat peculiar with C14:0 and C16:0 at its sn-2 position. This method could provide a full structural profile of intact photosynthetic lipid molecular species, which may be applied to study the physiological and ecological functions of lipid by monitoring their individual changes.
Precise identification of photosynthetic glycerolipids in microalga Tetraselmis chuii by UPLC-ESI-Q-TOF-MS

LI HaiYing,YAN XiaoJun,Xu JiLin &,ZHOU ChengXu,

中国科学C辑(英文版) , 2008,
Abstract: Precise structural identification of photosynthetic polar glycerolipids in microalga Tetraselmis chuii has been established using Ultra Performance Liquid Chromatography-Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry (UPLC-ESI-Q-TOF-MS) by direct analysis of the total lipids extract. The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in both positive and negative modes. The structural determination was based on the characteristic product ions yielded by different glycerolipids under ESI-MS/MS mode, and confirmed the molecular species by the carboxylate anions produced by glycerolipids in the negative mode. As a result, more than 40 lipid molecular species, including 11 monogalactosyldiacylglycerols (MGDG), 7 digalactosyldiacylglycerols (DGDG), 16 sulfoquinovosyldiacylglycerols (SQDG), and 9 phosphatidylglycerols (PG), were detected in Tetraselmis chuii, which had never been identified before in this microalga. Furthermore, some intact lipid molecules with hydroxylated fatty acids that could not be detected by the traditional GC-MS method were found this time, providing novel information for the photosynthetic lipidome of Tetraselmis chuii. Comparative studies on fatty acids at the sn-2 position showed that SQDG and MGDG are dominantly biosynthesized through the prokaryotic pathway, PG is a typically mixed biosynthetic pathway, while DGDG is somewhat peculiar with C14:0 and C16:0 at its sn-2 position. This method could provide a full structural profile of intact photosynthetic lipid molecular species, which may be applied to study the physiological and ecological functions of lipid by monitoring their individual changes. Supported by the Program for Changjiang Scholars and Innovative Research Team in Universities (PCSIRT) (Grant No. IRT0734), Project of National Ocean Bureau (Grant No. 200805067), Project of Ministry of Science and Technology (Grant No. 2007BAD43B09), and K. C. Wong Magna Fund in Ningbo University
Who Will Retweet This? Automatically Identifying and Engaging Strangers on Twitter to Spread Information
Kyumin Lee,Jalal Mahmud,Jilin Chen,Michelle Zhou,Jeffrey Nichols
Computer Science , 2014,
Abstract: There has been much effort on studying how social media sites, such as Twitter, help propagate information in different situations, including spreading alerts and SOS messages in an emergency. However, existing work has not addressed how to actively identify and engage the right strangers at the right time on social media to help effectively propagate intended information within a desired time frame. To address this problem, we have developed two models: (i) a feature-based model that leverages peoples' exhibited social behavior, including the content of their tweets and social interactions, to characterize their willingness and readiness to propagate information on Twitter via the act of retweeting; and (ii) a wait-time model based on a user's previous retweeting wait times to predict her next retweeting time when asked. Based on these two models, we build a recommender system that predicts the likelihood of a stranger to retweet information when asked, within a specific time window, and recommends the top-N qualified strangers to engage with. Our experiments, including live studies in the real world, demonstrate the effectiveness of our work.
A Novel Source of Methylglyoxal and Glyoxal in Retina: Implications for Age-Related Macular Degeneration
Kee Dong Yoon, Kazunori Yamamoto, Keiko Ueda, Jilin Zhou, Janet R. Sparrow
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041309
Abstract: Aging of retinal pigment epithelial (RPE) cells of the eye is marked by accumulations of bisretinoid fluorophores; two of the compounds within this lipofuscin mixture are A2E and all-trans-retinal dimer. These pigments are implicated in pathological mechanisms involved in some vision-threatening disorders including age-related macular degeneration (AMD). Studies have shown that bisretinoids are photosensitive compounds that undergo photooxidation and photodegradation when irradiated with short wavelength visible light. Utilizing ultra performance liquid chromatography (UPLC) with electrospray ionization mass spectrometry (ESI-MS) we demonstrate that photodegradation of A2E and all-trans-retinal dimer generates the dicarbonyls glyoxal (GO) and methylglyoxal (MG), that are known to modify proteins by advanced glycation endproduct (AGE) formation. By extracellular trapping with aminoguanidine, we established that these oxo-aldehydes are released from irradiated A2E-containing RPE cells. Enzyme-linked immunosorbant assays (ELISA) revealed that the substrate underlying A2E-containing RPE was AGE-modified after irradiation. This AGE deposition was suppressed by prior treatment of the cells with aminoguanidine. AGE-modification causes structural and functional impairment of proteins. In chronic diseases such as diabetes and atherosclerosis, MG and GO modify proteins by non-enzymatic glycation and oxidation reactions. AGE-modified proteins are also components of drusen, the sub-RPE deposits that confer increased risk of AMD onset. These results indicate that photodegraded RPE bisretinoid is likely to be a previously unknown source of MG and GO in the eye.
The Librating Companions in HD 37124, HD 12661, HD 82943, 47 Uma and GJ 876: Alignment or Antialignment?
Jianghui Ji,Lin Liu,H. Kinoshita,Jilin Zhou,H. Nakai,Guangyu Li
Physics , 2003, DOI: 10.1086/377038
Abstract: We investigated the apsidal motion for the multi-planet systems. In the simulations, we found that the two planets of HD 37124, HD 12661, 47 Uma and HD 82943 separately undergo apsidal alignment or antialignment. But the companions of GJ 876 and $\upsilon$ And are only in apsidal lock about $0^{\circ}$. Moreover, we obtained the criteria with Laplace-Lagrange secular theory to discern whether a pair of planets for a certain system are in libration or circulation.
Possible Influence of Arctic Oscillation on Winter Visibility over Eastern China  [PDF]
Yu Gu, Xiaomeng Shi, Jilin Sun
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.58006
Abstract: NCEP/NCAR reanalysis data, the Arctic Oscillation (AO) index and the atmospheric visibility (Vis) data at 134 sites in eastern China (ECN) are used to investigate the possible influence of AO on the wintertime weather and Vis over ECN. A higher relative humidity (RH, compared with the normal year) is identified over ECN in the winters with a positive phase of AO, and the wind anomaly is generally inshore in the coast areas of China. All these processes are consistent with Vis degradation over ECN. On the contrary, in the winters with a negative phase of AO, a lower RH can be identified over ECN, and the wind anomaly is generally offshore, which is favorable for Vis improvement.
A study on surface nuclear magnetic resonan ce over layered conductive earth
层状导电介质中地面核磁共振响应特征理论 研究

WENG Ai Hua LI Zhou Bo WANG Xue Qiu Jilin Unversity,
翁爱华
,李舟波,王雪秋

地球物理学报 , 2004,
Abstract: Numerical simulation technique of surface nuclear magnetic resonance (NMR) responses from stratified groundwater formation with finite conductivity is concerned with two problems. One is the integration of Hankel transform of a rapidly oscillating kernel function, and another is the volume integration of surface NMR signal induced in a receiver loop from the protons in buried aquifer. In this paper, a direct numerical integration method is applied to the oscillating kernel function integration to obtain radial and vertical components of magnetic fields from a large loop source, and the spatial characteristics of the fields are described. Due to the distribution of magnetic fields, an ununiform space interval subdivision method has been developed to estimate surface NMR response in the receiver loop in order to save computing time. The surface NMR responses from different models have been evaluated, and influences of model conductivity, aquifer depth and its thickness, and loop size have been discussed. Numerical results show that the combination of direct numerical integration and ununiform space interval subdivision is feasible to get surface NMR signal. And the conductivity of formation is the key to generate the phase of surface NMR signal, but other factors, such as groundwater depth and its thickness, loop size, can make the amplitude and phase of surface NMR response greatly different.
Positive feedback of winter ocean-atmosphere interaction in Northwest Pacific
Xiaojie Zhu,Jilin Sun
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-2098-9
Abstract: Using monthly mean atmospheric reanalysis data and oceanic assimilation data product, the winter ocean-atmosphere interaction in middle and high latitude in Northwest Pacific was studied. Key regions were chosen to study the variations of Aleutian Low, the 500hPa westerly, the meriodional sea surface temperature (SST) gradient with three indices defined as Aleutian Low index, zonal index and meridional SST gradient between Kuroshio-influenced region and Oyashio-influenced region. The results show that when there is a deeper Aleutian Low accompanied by a stronger northerly wind in the westem part of the Aleutian Low, the subpolar gyre of North Pacific is strengthened, the SST in the Oyashio-influenced region is decreased and the meridional SST gradient between Kuroshio-influ-enced region and Oyashio-influenced region is increased, which, in tum, will enhance the westerly jet in the upper troposphere due to thermal-wind relation. The strengthened westerly jet makes a favorable condition for the deeper Aleutian Low over North Pacific beneath the left part of the jet exit region. Consequently, a positive feedback forms there.
Development of a New Electrode for Arc Wclding of Austempercd Ductile Iron(ADI)
SUN Daqian ZHOU Zhenfeng ZHAO Zongju Welding Division,Jilin University of Technology,Changchun,China To whom correspondence should be addressed,
孙大谦
,周振丰,赵宗举

材料科学技术学报 , 1992,
Abstract: The effect of Ca,Ba,Bi and Al on the amount of carbide in ductile iron weld metal,the microstructural characteristics of ADI weld metal and the effect of heat treatment process on the microstructure and mechanical properties of ADI weld metal have been studied.On this basis the optimum composition of weld and the optimum heat treatment process of ADI weld metal were de- termined and a new electrode for arc cold-welding (i.e.,without preheat) of ADI was developed.The ductile iron welded joint free from eutectic carbide can be produced by using this electrode before austempering and the weld metal obtained after austempering has a microstructure and mechanical properties similar to those of ADI.The mechanical properties of welded joints can match the require- ment of ADI.
Impact of the Barents Sea SST in Autumn on the Winter Climate in Northeast China  [PDF]
Xiaomeng Shi, Yu Gu, Jilin Sun, Jingshu Dong, Min Geng
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.57009
Abstract: We studied effects of sea surface temperature anomaly (SSTA) in the Barents Sea in autumn on the atmospheric circulation in northeast China in winter, using the NCEP reanalysis data and sea surface temperature (SST) data of the Hadley Center. The results show that the ocean thermal conditions in the Barents Sea in autumn can be used as an important reference factor for predicting the cold air activity in China. When the sea surface temperature anomaly of the Barents Sea elevated in the autumn, the sea-level pressure anomaly elevated in eastern China on December, northeast China and southeastern Russia on January and February. In the years when the SSTA of the Barents Sea elevated in the autumn, the abnormal high-pressure ridge developed over Europe, and the geopotential height in western China appeared negative anomaly at 500 hPa. At 1000 hPa, the Mongolia high-pressure increased and the northerly airflow strengthened the cold high-latitude air broke out to the south, which was easy to affect northeast and north of China. In negative SSTA years, the high-pressure ridge was west to the north Atlantic, and the geopotential height in central and northern Siberia appeared negative anomaly at 500 hPa; the Mongolia high-pressure was weakened at 1000 hPa.
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