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:B. Tong, Z. Tan, X. Lv, L. Sun, F. Xu, Q. Shi, and Y. Li
The molar heat capacities Cp,m of 2,2-dimethyl-1,3-propanediol were measured in the temperature range from 78 to 410 K by means of a small sample automated
adiabatic calorimeter. A solid-solid and a solid-liquid phase transitions were found at T-314.304 and 402.402 K, respectively, from the experimental Cp-T curve. The molar enthalpies and entropies of these transitions were determined to be 14.78 kJ mol−1, 47.01 J K−1 mol− for the solid-solid transition and 7.518 kJ mol−1, 18.68 J K−1 mol−1 for the solid-liquid transition, respectively. The dependence of heat capacity on the temperature was fitted to the following
polynomial equations with least square method. In the temperature range of 80 to 310 K, Cp,m/(J K−1 mol−1)=117.72+58.8022x+3.0964x2+6.87363x3−13.922x4+9.8889x5+16.195x6; x=[(T/K)−195]/115. In the temperature range of 325 to 395 K, Cp,m/(J K−1 mol−1)=290.74+22.767x−0.6247x2−0.8716x3−4.0159x4−0.2878x5+1.7244x6; x=[(T/K)−360]/35. The thermodynamic functions HT−H298.15 and ST−S298.15, were derived from the heat capacity data in the temperature range of 80 to 410 K with an interval of 5 K. The thermostability
of the compound was further tested by DSC and TG measurements. The results were in agreement with those obtained by adiabatic
Authors:J. Zhang, J. Zeng, Y. Liu, L. Sun, F. Xu, W. You, and Y. Sawada
Pb(1,4-BDC)·(DMF)(H2O) (1,4-BDC=1,4-benzenedicarboxylate; DMF=dimethylformamide) has been synthesized and investigated by elemental analysis,
FTIR spectroscopy, thermogravimetry (TG), derivative thermogravimetry (DTG). TG-DTG curves show that the thermal decomposition
occurs in four stages and the corresponding apparent activation energies were calculated with the Ozawa-Flynn-Wall (OFW) and
the Friedman methods. The most probable kinetic model function of the dehydration reaction of the compound has been estimated
by the Coats-Redfern integral and the Achar-Bridly-Sharp differential methods in this study.
Authors:Y. Qi, F. Xu, H. Ma, L. Sun, J. Zhang, and T. Jiang
Polyaniline/γ-Al2O3 (PANI/γ-Al2O3) composites were synthesized by in-situ polymerization at the presence of HCl as dopant by adding γ-Al2O3 nanoparticles into aniline solution. The composites were characterized by FTIR and XRD. The thermogravimetry (TG) and modulated
differential scanning calorimetry (MDSC) were used to study the thermal stability and glass transition temperature (Tg) of the composites, respectively.
The results of FTIR showed that γ-Al2O3 nanoparticles connected with the PANI chains and affected the absorption characteristics of the composite through the interaction
between PANI and nano-sized γ-Al2O3. And the results of XRD indicated that the peaks intensity of the PANI/γ-Al2O3 composite were weaker than that of the pure PANI. From TG and derivative thermogravimetry (DTG) curves, it was found that
the pure PANI and the PANI/γ-Al2O3 composites were all one step degradation. And the PANI/γ-Al2O3 composites were more thermal stable than the pure PANI. The MDSC curves showed that the nano-sized γ-Al2O3 heightened the glass transition temperature (Tg) of PANI.
Authors:J. Zeng, Y. Liu, Z. Cao, J. Zhang, Z. Zhang, L. Sun, and F. Xu
We prepared PANI/tetradecanol/MWNTs composites via in-situ polymerization. DSC results indicated that the composites are good
form-stable phase change materials (PCMs) with large phase change enthalpy of 115 J g−1. The MWNTs were randomly dispersed in the composites and significantly enhanced the thermal conductivity of the PCMs from
0.33 to 0.43 W m−1 K−1. The form-stable PCMs won’t liquefy even it is heated at 80°C, so that the MWNTs were fixed in the composite and the phase
separation of the MWNTs from PANI/tetradecanol/MWNTs composites won’t occur.
Authors:J. Zeng, J. Zhang, Y. Liu, Z. Cao, Z. Zhang, F. Xu, and L. Sun
Polyaniline (PANI)/1-tetradecanol (TD) composite materials, a kind of novel composite that can conduct electricity and store
thermal energy at the same time, thus possess the ability to endure certain heat shock, were prepared for the first time.
FTIR and XRD results showed that there were some interactions existed between PANI and TD. The thermal stability of the composites
exhibited both the characteristics of PANI and TD. The DSC experiments showed that the highest phase change enthalpy of the
composites could be as 73% as that of TD, indicating it was a good form-stable phase change material. The thermal conductivity
of the composites was also improved. The AC (Alternating Current) conductivity of the composites was enhanced to close to
that of PANI when the mass fraction of PANI in the composite was increased to 46%. Heat shock experiments showed that the
heat shock resistibility of the composite was greatly improved comparing to that of pure PANI.
Authors:Z. Zhang, L. Sun, Z. Tan, F. Xu, X. Lv, J. Zeng, and Y. Sawada
The molar heat capacities of the room temperature ionic liquid 1-butylpyridinium tetrafluoroborate (BPBF4) were measured by an adiabatic calorimeter in temperature range from 80 to 390 K. The dependence of the molar heat capacity
on temperature is given as a function of the reduced temperature X by polynomial equations, Cp,m [J K−1 mol−1]=181.43+51.297X −4.7816X2−1.9734X3+8.1048X4+11.108X5 [X=(T−135)/55] for the solid phase (80–190 K), Cp,m [J K−1 mol−1]= 349.96+25.106X+9.1320X2+19.368X3+2.23X4−8.8201X5 [X=(T−225)/27] for the glass state (198–252 K), and Cp,m[J K−1 mol−1]= 402.40+21.982X−3.0304X2+3.6514X3+3.4585X4 [X=(T−338)/52] for the liquid phase (286–390 K), respectively. According to the polynomial equations and thermodynamic relationship,
the values of thermodynamic function of the BPBF4 relative to 298.15 K were calculated in temperature range from 80 to 390 K with an interval of 5 K. The glass transition
of BPBF4 was observed at 194.09 K, the enthalpy and entropy of the glass transition were determined to be ΔHg=2.157 kJ mol−1 and ΔSg=11.12 J K−1 mol−1, respectively. The result showed that the melting point of the BPBF4 is 279.79 K, the enthalpy and entropy of phase transition were calculated to be ΔHm = 8.453 kJ mol−1 and ΔSm=30.21 J K−1 mol−1. Using oxygen-bomb combustion calorimeter, the molar enthalpy of combustion of BPBF4 was determined to be ΔcHm0 = −5451±3 kJ mol−1. The standard molar enthalpy of formation of BPBF4 was evaluated to be ΔfHm0 = −1356.3±0.8 kJ mol−1 at T=298.150±0.001 K.
Authors:J. Zhang, Y. Liu, J. Zeng, F. Xu, L. Sun, W. You, and Y. Sawada
Zinc formate dihydrate has been synthesized and characterized by powder X-ray diffraction, elemental analysis, FTIR spectra
and thermal analysis. The molar heat capacity of the coordination compound was measured by a temperature modulated differential
scanning calorimetry (TMDSC) over the temperature range from 200 to 330 K for the first time. The thermodynamic parameters
such as entropy and enthalpy vs. 298.15 K based on the above molar heat capacity were calculated. The thermal decomposition characteristics of this compound
were investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). TG curve showed that the
thermal decomposition occurred in two stages. The first step was the dehydration process of the coordination compound, and
the second step corresponded to the decomposition of the anhydrous zinc formate. The apparent activation energy of the dehydration
step of the compound was calculated by the Kissinger method using experimental data of TG analysis. There are three sharply
endothermic peaks in the temperature range from 300 to 650 K in DSC curve.