Authors:T. C. K. Yang, W. H. Chang, and D. S. Viswanath
Thermal degradation of poly(vinyl butyral) (PVB) and its mixtures with alumina, mullite and silica was investigated by non-isothermal thermogravimetry in the temperature range of 323 to 1273 K. The analysis of the data was carried out using a three-dimensional diffusion model. Results showed that the kinetic parameters (activation energy and pre-exponential factor) of the PVB degradation are different for polymer alone, and ceramic/polymer composites. The overall weighted mean apparent activation energy showed an increasing reactivity in the order of PVB<alumina+PVB<mullite+PVB<silica+PVB. This shows that the acidic and basic surface characteristics of the ceramics promote the thermal degradation of PVB and, the more acidic silica affects the degradation more than mullite and alumina. The effect of pellet compression pressure in the range of 4000 to 8000 psig is also investigated.
Authors:W. Dan, Y. Di, Y. Kong, Q. Wang, W. Yang, and D. Wang
The complex (C11H18NO)2CuCl4(s) was synthesized. Chemical analysis, elemental analysis, and X-ray crystallography were used to characterize the structure
and composition of the complex. Low-temperature heat-capacities of the compound were measured by an adiabatic calorimeter
in the temperature range from 77 to 400 K. A phase transition of the compound took place in the region of 297–368 K. Experimental
molar heat-capacities were fitted to two polynomial equations of heat-capacities as a function of the reduced temperature
by least square method. The peak temperature, molar enthalpy, and entropy of phase transition of the compound were calculated
to be Ttrs = 354.214 ± 0.298 K, ΔtrsHm = 76.327 ± 0.328 kJ mol−1, and ΔtrsSm = 51.340 ± 0.164 J K−1 mol−1.
Authors:Y. P. Liu, Y. Y. Di, W. Y. Dan, D. H. He, Y. X. Kong, and W. W. Yang
Dodecylamine hydrochloride C12H25NH3·Cl(s) and bis-dodecylammonium tetrachlorozincate (C12H25NH3)2ZnCl4(s) were synthesized by the method of liquid phase reaction. The constant-volume energy of combustion of dodecylamine hydrochloride was measured by means of a RBC-II precision rotating-bomb combustion calorimeter at T = (298.15 ± 0.001) K. The standard molar enthalpy of formation of C12H25NH3·Cl(s) was calculated to be
(C12H25NH3·Cl, s) = −(706.79 ± 3.97) kJ mol−1 from the constant-volume energy of combustion. In accordance with Hess’ law, a reasonable thermochemical cycle was designed and the enthalpy change of the synthesis reaction of the complex (C12H25NH3)2ZnCl4(s) was determined by use of an isoperibol solution-reaction calorimeter. The standard molar enthalpy of formation of (C12H25NH3)2ZnCl4(s) was calculated as
[(C12H25NH3)2ZnCl4, s] = −(1862.14 ± 7.95) kJ mol−1 from the standard molar enthalpy of formation of C12H25NH3·Cl(s) and other auxiliary thermodynamic data.
Authors:G. D. Ye, H. Zhou, J. W. Yang, Z. H. Zeng, and Y. L. Chen
Photoinitiating behaviors of oligo(α-aminoketones) (OAK) macrophotoinitiator
containing aminoalkylphenone group on free-radical photopolymerization had
been investigated by differential photo-calorimetry (DPC). The macrophotoinitiator
showed comparative performance with those commercial photoinitiators with
lower molecular mass. The effect of photoinitiator concentrations and UV intensity
on the polymerization rate was investigated, and the value of exponential
factor was found to be 0.5 at the beginning of polymerization, suggesting
that the photopolymerization initiated by OAK followed biradical termination
mechanism. Photosensitizer isopropyl thioxanthone (ITX) and oxygen severely
restricted the polymerization in these systems. Photoinitiators with lower
molecular mass showed higher reactivity than those with higher molecular mass.
Authors:Z. Wang, M. Lv, D. Li, Z. Zhou, L. Zhang, and W. Yang
A new HPLC method has been established for determination of 3-monoiodotyrosine (MIT), 3,5-diiodotyrosine (DIT), 3,5-diiodothyronine (T2), 3,3′,5-triiodothyronine (T3), 3,3′,5′-triiodothyronine (rT3), and thyroxine (T4) produced by hydrolysis of iodinated casein with barium hydroxide. The hydrolytic stability of each analyte was evaluated. Iodinated casein was hydrolyzed with saturated barium hydroxide solution for 16 h at 110°C and the barium ions were then removed as barium sulfate. Reversed-phase HPLC was performed on a 2.1 mm × 150 mm, 5 μm particle, C18 column with a mixture of acetonitrile and 0.1% (v/v) formic acid as mobile phase at a flow rate of 0.2 mL min–1. Acetonitrile was maintained at 5% (v/v) for 5 min and then increased linearly to 50% (v/v) within 35 min. All analytes were quantified by measuring the absorbance at 280 nm. Validation data indicated the method was linear, with regression coefficients (R2) > 0.998, in the concentration ranges investigated. Sensitivity was adequate—limits of detection (LOD) were 0.04–0.38 μg mL–1 and limits of quantification (LOQ) were 0.05–0.38 μg mL–1. Accuracy and precision were acceptable — for all the analytes recovery was 82.0–93.0% and repeatability, as relative standard deviation, was 1.0–3.0%. Hydrolytic stability tests indicated MIT and DIT are much more stable than the other analytes. rT3 was not released directly from iodinated casein but was formed by deiodination of T4 during hydrolysis. The method could be used to identify iodinated casein, to evaluate its activity and quality, and for supervision and regulation of feed additives.
Authors:T.-K. Wang, Y.-D. Yang, B. Du, S. Yu, and W.-L. Hou
Chestnut exhibits anti-inflammatory, styptic, anti-diarrhea, and analgestic effects as a traditional Chinese medicine. There is increasing evidence that shows that the consumption of chestnuts has become more important in human nutrition due to the health benefits provided by the antioxidants. The phenolic compounds are responsible for major bioactivities, such as anti-tumor and anti-oxidation. A high-performance liquid chromatography (HPLC) method with diode array detection (DAD) was established for the simultaneous determination of six phenolic compounds (gallic acid, GA; protocatechuic acid, PR; catechin, CA; epicatechin, EP; quercetin, QU; kaempferol, KA) in Chinese chestnut (Castanea mollissima blume) kernel. The sample followed by separation on Eclipse XDB-C18 column (150 × 4.6 mm, id., 5 μm) with gradient elution of methanol-1.0% acetate acid solution as a mobile phase, at a temperature of 30°C, under the ratio of 1.2 mL min−1, with 5 μL injection volume, and multi-wavelength synthesis was used with DAD. The correlation coefficients were larger than 0.999, the recoveries were 97.58% for GA, 100.41% for PA, 96.23% for CA, 101.38% for QU, 99.15% for EP, and 98.60% for KA, relative standard deviation (RSD) were 1.04% for GA, 1.21% for PA, 1.09% for CA, 1.19% for QU, 1.06% for EP, and 1.20% for KA. This method was applied for the determination of phenolics in chestnut kernel and was found to be fast, sensitive, and suitable.
Authors:H.-L. Liu, S.-J. Liu, Z.-L. Xiao, Q.-Y. Chen, and D.-W. Yang
Excess molar enthalpies of binary mixtures for tributyl
phosphate (TBP)+methanol/ethanol were measured with a TAM air Isothermal calorimeter
at 298.15 K and ambient. The results for xTBP+(1–x)CH3OH
are negative in the whole range of composition, while the values for xTBP+(1–x)C2H5OH
change from positive values at low x to
small negative values at high x. The experimental
results have been correlated with the Redlich–Kister polynomial. IR
spectra of the mixtures were measured to investigate the effect of hydrogen
bonding in the mixture.
Authors:J. Lu, G.Z. Ji, G. Li, Y.F. Wu, J. Yang, S.L. Lin, D.L. Yang, J.N. Zhao, and W.M. Xiu
Global rice supplies have been found contaminated with unapproved varieties of genetically modified (GM) rice in recent years, which has led to product recalls in several of countries. Faster and more effective detection of GM contamination can prevent adulterated food, feed and seed from being consumed and grown, minimize the potential environmental, health or economic damage. In this study, a simple, reliable and cost-effective multiplex polymerase chain reaction (PCR) assay for identifying genetic modifications of TT51-1, Kemingdao1 (KMD1) and Kefeng6 (KF6) rice was developed by using the event-specific fragment. The limit of detection (LOD) for each event in the multiplex PCR is approximately 0.1%. Developed multiplex PCR assays can provide a rapid and simultaneous detection of GM rice.
Aegiolops kotschyi cytoplasmic male sterile system often results in part of haploid plants in wheat (Triticum aestivum L.). To elucidate the origin of haploid, 235 wheat microsatellite (SSR) primers were randomly selected and screened for polymorphism between haploid (2n = 3x = 21 ABD) and its parents, male-sterile line YM21 (2n = 6x = 42 AABBDD) and male fertile restorer YM2 (2n = 6x = 42 AABBDD). About 200 SSR markers yielded clear bands from denatured PAGE, of which 180 markers have identifiable amplification patterns, and 20 markers (around 8%) resulted in different amplification products between the haploid and the restorer, YM2. There were no SSR markers that were found to be distinguishable between the haploid and the male sterile line YM21. In addition, different distribution of HMW-GS between endosperm and seedlings from the same seeds further confirmed that the haploid genomes were inherited from the maternal parent. After haploidization, 1.7% and 0.91% of total sites were up- and down-regulated exceeding twofold in the shoot and the root of haploid, respectively, and most of the differentially expressed loci were up/down-regulated about twofold. Out of the sensitive loci in haploid, 94 loci in the shoot, 72 loci in the root can be classified into three functional subdivisions: biological process, cellular component and molecular function, respectively.