Air samples were collected at a downtown site in Beijing from January to July 2004 and analyzed by instrumental neutron activation
analysis (INAA) combined with organic solvent extraction method for the concentrations and distributions of extractable organohalogens
(EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and organoiodinated compounds (EOI). The concentrations
of EOX were increasing in the order of EOCl >> EOBr ~ EOI in both gaseous and particulate phase. EOCl accounted for 75.8-100%
and 83.7-100% of EOX in particulate and gaseous phase, respectively, suggesting that EOCl was the major component of the organohalogens
in the atmosphere. In the plots of the logarithm of the EOX concentrations versus the reciprocal temperature, their linear
relations were observed for EOCl (R = -0.9), for EOBr (R = -0.6) and EOI (R = -0.7) in gaseous phase, which indicated that
the concentrations of EOCl, EOBr and EOI in gaseous phase exhibited a strong temperature dependence, i.e., their concentrations
increased with increasing of temperature.
Garlic is widely used as food flavouring, and China is the world's largest garlic producer and exporter. To develop a convenient technique for evaluation of garlic cultivars would be worthwhile, and it would have wide application in such a huge market. In this research, 3D front-face fluorescence data of 8 garlic cultivars were recorded, and independent component analysis was used to decompose the overall fluorescence spectra into six independent components. The first, second, and fourth independent components showed a big difference among the cultivars, and the chemical fluorophores behind these three components were specified as protein, vitamin B6, and ATP, respectively, as fluorescent markers for evaluation. The result showed that all 8 cultivars cluster separately. The cultivar “YNQJ” have the highest quality in terms of protein and vitamin B6, “NXYC” and “SDHB” have the highest content of ATP, while “SXXA” is the poorest in terms of protein and ATP, and “HNJZ” has the lowest content of vitamin B6. Therefore, rapid evaluation of garlic cultivars can be accomplished successfully by using only the proportion values of three properly selected fluorescent markers.
In our invention, FCC (fluid catalytic cracking) dry gas could be used to react with benzene without any special purification, and more than 90% ethylene was converted to ethylbenzene. The phenomenon of carbon deposition over catalyst surface was obvious and leads to a deactivation of catalyst, so it is important to study the behavior of carbon deposition of catalyst during alkylation of benzene. The influence of several factors such as temperature, reaction time, reactant concentration of the amount and the kinetics of carbon deposition were investigated, during which carbon depositing rate equations were obtained for different reactant.
Authors:J. Liu, D. He, L. Xu, H. Yang, and Q. Wang
The combustion behavior of Shuangya Mountain (SYM) coal dust has been investigated by means of TG in this paper. The reaction fraction can be obtained from isothermal TG data. The regressions of g(), an integral function of
vs. t for different reaction mechanisms were performed. The mechanism of nucleation and nuclei growth is determined as the controlling step of the coal dust combustion reaction by the correlation coefficient of the regression, and the kinetic equation of the SYM coal dust combustion reaction has been established.
Authors:Z. Ren, Y. Mao, Q. Zhi, C. Xu, and T. Dong
The synthesis of superheavy elements is now a hot topic in nuclear physics. Alpha-decay and spontaneous fission are two main
decay modes in heavy and superheavy regions. Theoretical studies on alpha radioactivity and spontaneous fission can provide
useful information for experiments. We investigate the alpha-decay and spontaneous fission of heavy and superheavy nuclei
with different models. This includes the alpha-decay energies, alpha decay half-lives, and half-lives of spontaneous fission.
The theoretical alpha-decay half-lives are in good agreement with experimental ones. The calculated half-lives of spontaneous
fission are in reasonable agreement with present data. The properties of unknown nuclei are predicted.
Authors:Q. Xu, W.J. Feng, H.R. Peng, Z.F. Ni, and Q.X. Sun
Members of WRKY gene family encode transcription factors involved in plant developmental processes and response to biotic and abiotic stresses. In order to understand the function of the TaWRKY71 gene, a homologue gene was isolated and characterised in wheat (Triticum aestivum L.) genotype TAM107. Tissue-specific gene expression profiles indicated that TaWRKY71 was constitutively expressed in roots, stems, leaves, stamen and pistil. The relative expression of TaWRKY71 was elucidated under ABA treatment and other abiotic stresses. In agreement with this, several putative cis-acting elements involved in ABA-response, drought-inducibility, low-temperature and heat response were detected in the promoter region of TaWRKY71. The function of TaWRKY71 was further determined by transforming Arabidopsis thaliana. Transgenic plants over-expressing TaWRKY71 displayed enhanced seed germination under ABA treatment and were tolerant to salt and drought stresses. These results indicate that TaWRKY71 gene might play important roles in seed germination and abiotic stress response.
Authors:J.C. Zheng, T. Liu, J.Q. Li, X. Wang, W.Y. Li, F. Xu, and Q.W. Zhan
Barley stripe mosaic virus (BSMV)-based virus induced gene silencing (VIGS) is an effective strategy for rapid determination of functional genes in wheat plants. ERECTA genes are reported to regulate stomatal pattern of plants, and manipulation of TaERECTA (a homologue of ERECTA in bread wheat) is a potential route for investigating stomatal development. Here, the leucine-rich repeat domains (LRRs) and transmembrane domains of TaERECTA were selected to gain BSMV:ER-LR and BSMV:ER-TM constructs, respectively, targeting TaERECTA for silencing in wheat cultivars ‘Bobwhite’ and ‘Cadenza’, to identify the function of TaERECTA on stomatal patterns. The results showed that reduced expression of TaERECTA caused an increased stomatal and epidermal cell density by average 13.5% and 3.3%, respectively, due to the significantly reduced size of leaf epidermal and stomatal cells, and this led to an increase in stomatal conductance. These suggest that modulation of TaERECTA offers further opportunities in stomatal engineering for the adaptation of photosynthesis in wheat.
Authors:Y. Gao, Q. Sun, R. Wang, J. Feng, F. Lin, N. Cui, X. Chen, S. Xu, Y. Bai, and X. Xu
Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici Eriks., is a major disease that causes substantial losses to wheat production worldwide. The utilization of effective resistance genes in wheat cultivars is the preferred control of the disease. To study the inheritance of all-stage resistance in spring wheat cultivars Louise, WA008016, Express, Solano, Alturas and Zak from the Pacific Northwest (PNW) of the United States, the six cultivars were crossed with the Chinese susceptible variety Taichung 29. Single-spore isolates of CYR32 and CYR33, the predominant Chinese races of P. striiformis f. sp. tritici, were used to evaluate F1, F2 and BC1 generations for stripe rust resistance under controlled greenhouse conditions. Genetic analysis determined that Louise had one dominant resistance gene to CYR32, temporarily designated as YrLou. WA008016 had two dominant and one recessive resistance genes to CYR32, temporarily designated as YrWA1, YrWA2 and YrWA3, respectively. Express had a single recessive gene that conferred resistance to CYR32, temporarily designated as YrExp3. The two independent dominant genes in Solano conferring resistance to CYR32 were temporarily designated as YrSol1 and YrSol2. Alturas had two recessive genes for resistance to CYR32, temporarily designated as YrAlt1 and YrAlt2. Zak has one dominant gene for resistance to CYR33, temporarily designated as YrZak1. These six cultivars can be important resistance sources in Chinese wheat stripe rust resistance breeding.
Authors:Q. Xu, H. Fan, Z. Jiang, Z. Zhou, L. Yang, F. Mei, and L. Qu
This research was aimed to study the cell wall degradation and the dynamic changes of Ca2+ and related enzymes in developing aerenchyma of wheat root under waterlogging. An examination of morphological development by light and electron microscope revealed that the structure of cell wall in middle cortical cells remained intact after 12 h of waterlogging and turned thinner after waterlogging for 24 h. At 48 h, the aerenchyma has been formed. The cellulase activity gradually increased in middle cortical cells within 24 h of waterlogging, and decreased with the formation of aerenchyma. Fluorescence detection and subcellular localization of Ca2+ showed the dynamic changing of Ca2+ at the cellular and subcellular levels during the development of aerenchyma. The activity of Ca2+-ATPase enhanced markedly in intercellular space, plasma membrane and tonoplast of some middle cortical cells after 8 h of waterlogging and remained high after 24 h, but it decreased after 48 h of waterlogging. All these suggests that cellulase, Ca2+ and Ca2+-ATPase show a dynamic distribution during the aerenchyma development which associated with the cell wall degradation of middle cortical cells. Moreover, there is a feedback regulation between Ca2+ and Ca2+-ATPase.
The study investigated the effects of environmental factors (salinity, pH, ions and activation media) on sperm motility (activation rate, duration of quick movement, and lifespan) and fertilization rate of Phascolosoma esculenta. The results showed that spermatozoa in the coelom and nephridium are able to move quickly. The optimal salinity was 14.64 to 43.35 and the optimal pH was 6.46 to 9.53 for sperm activation and motility, whereas the ranges for fertilization were narrower (18.56 to 30.3 for salinity and 6.46 to 8.61 for pH). Of the ions studied, Na+ was indispensable for sperm motility and fertilization, and Ca2+ and Mg2+ were necessary for fertilization. P. esculenta sperm could not fertilize eggs and have short lifespans in 200 to 600 mmol/L NaCl and KCl solutions. Furthermore, they could not be activated or move in 200 to 600 mmol/L CaCl2, MgSO4, and sucrose solutions.