Authors:S. Du, G. Zhang, H. Li, P. Wang, and X. Wang
The free-radical bulk polymerization of 2,2-dinitro-1-butyl-acrylate (DNBA) in the presence of 2,2′-azobisisobutyronitrile
(AIBN) as the initiator was investigated by DSC in the non-isothermal mode. Kissinger and Ozawa methods were applied to determine
the activation energy (Ea) and the reaction order of free-radical polymerization. The results showed that the temperature of exothermic polymerization
peaks increased with increasing the heating rate. The reaction order of non-isothermal polymerization of DNBA in the presence
of AIBN is approximately 1. The average activation energy (92.91±1.88 kJ mol −1) obtained was smaller slightly than the value of Ea=96.82 kJ mol−1 found with the Barrett method.
Authors:P. Zhu, S. Wang, J. Wang, L. Zhou, and P. Shi
In order to assess the contribution of adenosine triphosphate and its metabolites to the cellular metabolism process in Saccharomyces cerevisiae, it is very important to simultaneously determine the relative concentrations of ATP and its metabolites. In this study, a fast, simple reversed-phase high-performance liquid chromatography with high selectivity was developed to simultaneously measure adenosine triphosphate and its metabolites (adenosine diphosphate, adenosine monophosphate, and cyclic adenosine monophosphate) in yeast. The method was performed under the gradient grogram, and the detection was monitored at 254 nm. Analysis was achieved within 25 min. The four components can be detected with linear response over the concentration range from 1 to 100 mg L−1 with excellent correlation coefficients (r2) > 0.999. The recovery of the four analytes was 92.9%, 90.4%, 99.1%, and 105.1%, respectively. To demonstrate the good analysis of yeast samples, changes in the four adenine nucleotides levels caused by caloric restriction in yeast were determined. It is expected that the current method may contribute to further metabolomics and system biology investigations of yeast.
It has been generally accepted when estimating sedimentation rates using the 137Cs dating method that the position of the 137Cs maximum in a sediment profile represents the year 1963. In this paper we validated this approach by developing a model
in which the annual 137Cs global fallout flux for the Yangtze River estuary was established on the basis of the Tokyo flux corrected for precipitation
rates observed in Shanghai. As the 137Cs maxima in the sediment deposition profiles depend on the sedimentation rates, the sub-sampling intervals were calculated
accordingly. Higher measured than the calculated values were found in some cores, what may be due to fluctuating sedimentation
rates and an additional deposition of 137Cs from land-based sources. The study provides useful information on the reliability of the measured 137Cs maxima in sediment profiles frequently used for dating of sediments in marine (coastal regions, open seas) as well as in
terrestrial (lakes) environments.
Authors:B. Peng, P. Li, S. Lai, Y. Wang, L. Yang, and Y. Wang
High ozone (O3) can cause great damage to plants. However, the effect of high O3 on nitrogen (N) absorption, distribution, and utilization in rice at different growth stages under different planting densities is poorly understood. In the present study, a conventional cultivar (Yangdao 6) and a hybrid cultivar (II You 084) with different planting densities were exposed to an elevated amount of O3 (E-O3; 50% higher than that of the control, C-O3) under a freeair gas concentration enrichment (FACE) system. N absorption, distribution, and utilization of the green leaves, stems, and shoots at tillering, jointing heading, and maturity were investigated. Results showed that E-O3 significantly increased the N content in the shoots of Yangdao 6 by 7.5%, 12.7%, and 19.6%, respectively, at jointing, heading, and maturity. Also, the N content in the shoots of II You 084 increased by 5.4%, 6.5%, and 8.4% at the corresponding growth stage upon E-O3 application. E-O3 significantly decreased N accumulation of II You 084 by 8.3%, 4.9%, 4.7%, and 19.2%, respectively, at tillering, jointing, heading, and maturity. Further, E-O3 had a decreasing effect on the N distribution in green leaves (p ≤ 0.05) of both cultivars, but exerted an increasing effect on that in the stems of both cultivars (p ≤ 0.05). In addition, E-O3 significantly decreased the N use efficiency (NUE) for biomass of the two cultivars in all growth stages. These results revealed that E-O3 could increase the N content in rice plants but decrease the N accumulation and utilization in both cultivars. The effects of E-O3 on N absorption, distribution, and utilization were not affected by planting density.
Authors:M.Y. Wang, P.S. Baenziger, I.S. El-Basyoni, and S.N. Wegulo
Fusarium head blight (FHB, caused by Fusarium graminearum) is a severe disease which threatens the yield and quality of harvested grain products, and hence causes major economic losses in wheat (Triticum spp.) and other small grain cereals. One of the infection routes for the pathogen is believed to be through the extruded anther. In order to study the role of the anther on FHB infection, FHB resistance was measured among wheat (Triticum aestivum L.) cultivars with non-extruded infertile anthers in cytoplasmic male sterile (CMS) lines and with extruded fertile anthers in their alloplasmic maintainer lines, and in an unrelated restorer line. We artificially inoculated the lines with F. graminearum (isolate NE 90) at 1.0 × 105 or 2.0 × 105 spores mL−1 for 72 or 96 hours. The results indicated that CMS cultivars were significantly more resistant than the maintainer and restorer cultivars. As the CMS lines differed from the maintainer lines by cytoplasm, anther health, anther extrusion, and seed set, additional experiments are needed to determine the role of each factor in infection. However, this research indicates that fertile anthers most likely are an important part of the infection pathway and of susceptibility to FHB.
Authors:S. Chiu, P. Wang, P. Kao, J. Lin, D. Lin, and C. Chen
Hair samples from junior high school students in metropolitan areas of Taichung, Taiwan were tested for a total of 13 elements,
Al, Ag, Br, Cl, Cr, Fe, K, La, Mn, Na, Sc, Se, and Zn by instrumental neutron activation analysis (INAA) to establish seasonal
variations, gender and environmental exposures. The seasonal variations of hairs in 39 healthy students (18 males and 21 females;
age 13.3 ± 0.4 years; height, 158.0 ± 4.1 cm; weight, 53.4 ± 5.7 kg) were collected at 1.5-month intervals for 1 year starting
from late August, 2008. The concentrations of the above elements varied from 103 to 10−2 μg g−1 at different sampling times. A quantified index of agreement (AT) was introduced to help classify the elements. A smaller
AT indicated highly consistent quantities of specific metals in the hair while a larger AT indicated increased fluctuation,
i.e., less agreement. The different ATs in various hair samples were discussed. The concentrations of these elements are compared
with the data in the literature.
Authors:J.-J. Zhang, R.-F. Wang, S.-P. Wang, H.-M. Liu, J.-B. Li, and J.-H. Bai
The complex of [Tb2(p-ClBA)6(PHEN)2] [(p-ClBA: p-chlorobenzoate and PHEN: 1,10-phenanthroline) was prepared and characterized by elemental analysis and IR spectroscopy. The
thermal behavior of [Tb2(p-ClBA)6(PHEN)2] in dynamic nitrogen atmosphere was investigated by TG-DTG, SEM and IR techniques. By the kinetic method of processing thermal
analysis data put forward by Malek et al., it is defined that the kinetic model for the first-step thermal decomposition is SB(m,n). The activation energy E and the pre-exponential factor lnA for this step reaction are 164 kJ mol-1 and
32.80, respectively. The lifetime equation at mass loss of 10% was deduced as lnτ=(-33.0569+20512.36/T by isothermal thermogravimetric
Authors:J. Wang, L. Jia, W. Wei, S. Lang, P. Shao, and X. Fan
This paper develops an instrumental analytical approach for detection of fourteen polycyclic aromatic hydrocarbons (PAHs) in edible oil samples using gel permeation chromatography (GPC) and ultra-high performance liquid chromatography (UHPLC) coupled with diode array detector (DAD), and fluorescence detector (FLD). The GPC was used to remove triglycerides from edible oil samples. The extracted samples were then detected using UHPLC—DAD—FLD. In order to obtain good separation and high reproducibility, the UHPLC—DAD—FLD experimental condition was optimized. The PAHs including three groups of isomeric PAHs can be separated completely in 12 min using BEH Shield RP 18 column with a suitable gradient elution program. The mean recoveries were in the range of 73–110% with an acceptable reproducibility (RSD < 10%, n = 3). During real sample analysis, the method can decrease the chance of false positives with both DAD and FLD being used simultaneously. The results indicate that the approach is simple, easy, and acceptably reproducible, thereby showing great potential as a method for detection of fourteen PAHs contained in edible oil samples.
Authors:A. Ren, S. Yu, J. Han, P. Chang, C. Chen, J. Chen, and X. Wang
Humic substances have attracted great interest in the investigation of metal ion behavior in the environment because of their
special properties. Sorption and complexation of Pb2+ on MX-80 bentonite, LA bentonite, alumina and silica as a function of pH were studied in the presence and absence of fulvic
acid (FA). The experiments were carried out in 0.01M and 0.001M NaNO3 solutions under ambient conditions. The results indicate that sorption of Pb2+ on the solid samples is strongly dependent on pH and FA. The sorption of Pb2+ is not influenced drastically by ionic strength. The nature of minerals/oxides, nature of humic substances and the composition
of the solution are important factors in the behavior of metal ions in the environment. The results also indicate that FA
has a positive effect on Pb2+ sorption at low and a negative effect at high pH values, and the results are discussed in the comparative complexation between
FA-Pb2+ and Pb2+-minerals.