Authors:L. Yang, F. Xu, L. Sun, Z. Tan, H. Tan, Z. Zhao, and J. Liang
technique based on the bacterial heat output was applied to evaluate the influence
of antibiotics PIP (Piperacillin Sodium)
and composite preparation of PIP and SBT (Sulbactam
Sodium) on the growth of E. coli
DH5α. The power–time curves of the growth metabolism of E. coli DH5α were studied using a TAM Air Isothermal
Microcalorimeter at 37C. By analyzing the power–time curves, the
parameters such as growth rate constants (k),
inhibitory ratio (I), the maximum heat
power (Pm) and the
time of the maximum heat power (tm)
were obtained. The results show that different concentrations of antibiotics
affect the growth metabolism of E. coli
DH5α. The PIP in the concentration range of 0–0.05 g mL–1
has a stimulatory effect on the E. coli
DH5α growth, while the PIP of higher concentrations (0.05 –0.25
g mL–1) can inhibit its growth. It seems
that the composite preparation composed of PIP and SBT cannot improve the
inhibitory effect on E. coli DH5α
as compared with the PIP.
Optimization of extraction ratio (ER) of tree peony seed protein (TPSP) was investigated using response surface methodology (RSM). The second-degree equation for ER of TPSP had high coeffi cient (0.9625) of determination. The probability (P) value of regression model signifi cance was less than 0.001 by analysis of central composite rotatable design. Relationships of ER to pH, liquid/solid ratio, squares of all factors, and cross-product factors (x2x3, x2x4, x3x4) were signifi cant (P<0.05). Whereas, extraction time, temperature, and cross-product terms (x1x2, x1x3, x1x4) were not signifi cant factors (P>0.05). Optimum extraction conditions were 3.42 h, pH 9.50, 50.80 ºC, and 9.54 ml g–1 of liquid/solid ratio with the maximum ER (43.60%) . SDS-PAGE indicated TPSP had mainly four proteins (180, 100, 60, and 35 kDa) with four subunits of 60, 48, 38, and 23 kDa. TPSP had a good amino acid composition with abundant essential amino acids (39.76%) determined by amino acid analysis.
Authors:R.D. Wang, Y.J. Deng, L.J. Sun, Y.L. Wang, Z.J. Fang, D.F. Sun, Q. Deng, and R. Gooneratne
Growth and haemolytic activity of several pathogenic Vibrio species were compared in egg-fried-rice with different egg ratios. Egg-fried-rice preparations with rice-to-egg ratios of 4:1, 1:1, and 1:4 were inoculated with either Vibrio parahaemolyticus, V. cholerae, V. vulnificus, or V. alginolyticus and incubated for 24 h. Cell number, thermostable direct haemolysin (TDH) activity, and total haemolytic activity were determined. The cell number and total haemolytic activity increased in all Vibrio strains after 24 h, and these were most marked in egg-fried-rice with the highest egg content (1:4 (rice:egg) ratio; P<0.05). V. alginolyticus exhibited the maximal growth and V. parahaemolyticus the highest haemolytic activity, but only V. parahaemolyticus ATCC 33847, V. alginolyticus CAMT 21162, and V. alginolyticus HY 91101 showed TDH activity. Results suggest that lowering egg content in egg-fried-rice could reduce growth and virulence of Vibrio pathogens.
Authors:F. Tian, L. Sun, S. C. Mojumdar, J. E. S. Venart, and R. C. Prasad
The transient hot-wire method is considered the most accurate technique to measure the thermal conductivity of fluids. In this study, a transient hot wire instrument which employs 25.4-μm-diameter tantalum wire with an insulating tantalum pentoxide coating has been used. This hot-wire cell with a thin insulating layer is suitable for measurement of the thermal conductivity of electrically conducting and polar liquids. Measurements of the thermal conductivity of 50 wt% solution of PAA [poly (acrylic acid)] in water and PAA–Na in 50 wt% water are reported here. These measurements were obtained in the temperature range of 299–368 K at 1 atmospheric pressure. The measurement of thermal conductivity is estimated to be accurate within ±4%.
Authors:B. Xue, X. Li, J. Wang, S. Yu, Z. Tan, and L. Sun
The heat capacities of trans-(R)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid in the temperature range from 78 to 389 K were measured
with a precise automatic adiabatic calorimeter. The sample was prepared with the purity of 0.9874 mole fraction. A solid-liquid
fusion phase transition was observed in the experimental temperature range. The melting point, Tm, enthalpy and entropy of fusion, ΔfusHm, ΔfusSm, were determined to be 344.75±0.02 K, 13.75±0.07 kJ mol−1, 39.88±0.21 J K−1 mol−1, respectively. The thermodynamic functions of the sample, H(T)-H(298.15), S(T)-S(298.15) and G(T)-G(298.15), were reported with a temperature interval of 5 K. The thermal decomposition of the sample was studied by TG analysis, the
thermal decomposition starts at ca. 421 K and terminates at ca. 535 K, the maximum decomposition rate was obtained at 525
K. The order of reaction, pre-exponential factor and activation energy, are n=0.14, A=1.15·108 min−1, E=66.27 kJ mol−1, respectively.
Authors:L. Tian, N. Ren, J. Zhang, H. Liu, S. Sun, H. Ye, and K. Wu
The two complexes of [Ln(CA)3bipy]2 (Ln = Tb and Dy; CA = cinnamate; bipy = 2,2′-bipyridine) were prepared and characterized by elemental analysis, infrared
spectra, ultraviolet spectra, thermogravimetry and differential thermogravimetry techniques. The thermal decomposition behaviors
of the two complexes under a static air atmosphere can be discussed by thermogravimetry and differential thermogravimetry
and infrared spectra techniques. The non-isothermal kinetics was investigated by using a double equal-double steps method,
the nonlinear integral isoconversional method and the Starink method. The mechanism functions of the first decomposition step
of the two complexes were determined. The thermodynamic parameters (ΔH≠, ΔG≠ and ΔS≠) and kinetic parameters (activation energy E and the pre-exponential factor A) of the two complexes were also calculated.
Authors:D. Wang, A. Bai, X. Lin, L. Fang, X. Shu, X. Shi, Q. Sun, and X. Wang
Supercritical fluid extraction (SFE) was used to extract shionone from Aster tataricus L. f. The effect of various parameters, i.e., temperature, pressure and sample particle size on yield was investigated with an analytical-scale SFE system to find the optimal conditions. The process was then scaled up by 50 times with a preparative SFE system under the optimized conditions of temperature 40 °C, pressure 30 MPa, and a sample particle size of 40–60 mesh. Then preparative high-speed counter-current chromatography was successfully used for isolation and purification of shionone from the SFE extract with a two-phase solvent system composed of n-hexane-methanol (2:1, volume ratio). The separation produced a total of 75 mg of shionone from 500 mg of the crude extract in one step separation with the purity of 98.7%, respectively, as determined by high-performance liquid chromatography (HPLC) and 92% recovery. The structure of shionone was identified by electrospray ionization-mass spectrometry (ESI-MS), hydrogen-1 nuclear magnetic resonance (1H-NMR), and carbon-13 nuclear magnetic resonance (13C-NMR).
Authors:J. Wang, L. Huang, H. Ren, Z. Sun, and Q. Guo
Soil seed banks can act as an important source in forest regeneration, and the information on the seed bank composition is vital for determining the resilience of plant communities under severe environments such as urban settings. In this study, we examined the seed bank density and functional composition, and their relationships with aboveground vegetation in three remnant evergreen broad-leaved forests, i.e., PuGang (PG), LuoGang (LG), and DaLingShan (DLS) under urbanization in Guangzhou, South China. In both years of our study (2010–2011), seed density and species richness for overall soil seed banks and each classified life forms (tree, shrub, herb and grass) significantly differed among the forests and were much higher in the PG forest. The prevailing life forms in the seed banks were herbs and grasses, and the proportion of tree species Importance Value index (IV) of the seed banks was low. We did not detect significant difference in the percentage of exotic species seeds in the seed banks among the forests. The proportion of species with animal dispersal mode was much higher in the DLS forest than in the PG and LG forests. The similarity in species composition between standing vegetation and seed banks was low with the lower value in the DLS forest than in PG and LG forest. Our findings suggest that the regeneration potential of the soil seed banks is limited for the remnant forests in urban areas. Therefore, greater proactive and enhanced conservation efforts are thus needed.
Authors:H. Ye, N. Ren, H. Li, J. Zhang, S. Sun, and L. Tian
The complex of [Nd(BA)3bipy]2 (BA = benzoic acid; bipy = 2,2′-bipyridine) has been synthesized and characterized by elemental analysis, IR spectra, single
crystal X-ray diffraction, and TG/DTG techniques. The crystal is monoclinic with space group P2(1)/n. The two–eight coordinated Nd3+ ions are linked together by four bridged BA ligands and each Nd3+ ion is further bonded to one chelated bidentate BA ligand and one 2,2′-bipyridine molecule. The thermal decomposition process
of the title complex was discussed by TG/DTG and IR techniques. The non-isothermal kinetics was investigated by using double
equal-double step method. The kinetic equation for the first stage can be expressed as dα/dt = A exp(−E/RT)(1 − α). The thermodynamic parameters (ΔH≠, ΔG≠, and ΔS≠) and kinetic parameters (activation energy E and pre-exponential factor A) were also calculated.
Authors:Chien C. Lin, C. F. Wang, Y.C. Sun, J. H. Chao, and C. L. Tseng
experiments have been carried out to investigate the effects of gamma-radiation
on iodine aerosols under various chemical conditions. The results indicate that
iodide ions (I-) in aerosol can be readily oxidized to I2
and HIO, and some iodide ions may be converted to organic iodine when organic
additives are present in the KI solution from which the aerosol is generated.
The results also suggest that the chemical transformation of irradiated iodine
aerosol depends on the chemical environment both carrier gas and iodide