In an ongoing effort to understand the thermodynamic properties of proteins, ovalbumin, lactoglobulin, lysozyme are studied
by adiabatic and differential scanning calorimetry over wide temperature ranges. The heat capacities of the samples in their
pure, solid states are linked to an approximate vibrational spectrum with the ATHAS analysis that makes use of known group
vibrations and a set of parameters, Θ1 and Θ3, of the Tarasov function for the skeletal vibrations. Good agreement is found between experiment and calculation with rms
errors mostly within ±3%. The analyses were also carried out with an empirical addition scheme using data from polypeptides
of naturally occurring amino acids. Due to space limitation, only selected results are reported.
A new, least-squares optimization method with interpolation is devised to fit skeletal vibrational heat capacities to the two parameters θ1 and θ3 in the Tarasov function used for heat capacity calculations of linear macromolecules. When heat capacities are available in the proper temperature range, θ1 and θ3 can be determined uniquely in a single computer run. Appended to our Advanced THermal Analysis System (ATHAS), this new method offers an improvement in analyzing heat capacity data and facilitates the systematic study of the physical significance of θ1 and θ3 values for all polymers and related molecules of the ATHAS data bank.
As a consequence
of their excellent barrier properties vinyl chloride/vinylidene chloride copolymers
have long been prominent in the flexible packaging market. While these polymers
possess a number of superior characteristics, they tend to undergo thermally-
induced degradative dehydrochlorination at process temperatures. This degradation
must be controlled to permit processing of the polymers. Three series of N-substituted
maleimides (N-alkyl-, N-aralkyl, and N-aryl) have been synthesized, characterized
spectroscopically, and evaluated as potential stabilizers for a standard vinyl
chloride/vinylidene chloride (85 mass%) copolymer. As surface blends with
the polymer, these compounds are ineffective as stabilizers. However, significant
stabilization may be achieved by pretreatment of the polymer with N-substituted
maleimides. The most effective stabilization of the polymer is afforded by
N-aralkyl- or N-arylmaleimides, most notably, N-benzylmaleimide and N-p-methoxyphenylmaleimide.
The organometallic precursor fac-[99mTc(CO)3(H2O)3]+ was reacted with N-ethoxy, N-ethyl dithiocarbamate (NOET) in phosphate buffered saline (pH 7.4) at room temperature for 30
minutes to produce the 99mTc(CO)3-NOET complex. The radiochemical purity (RCP) of the product was over 90% as measured by thin layer chromatography (TLC).
No decomposition of the complex at room temperature (RT) was observed over a period of 6 hours. Its partition coefficient
indicated that it was a lipophilic complex. The biodistribution comparison in mice of the 99mTc(CO)3-NOET complex and the 99mTcN-NOET complex showed that the former had a lower heart and brain uptake as compared to that of the latter, suggesting the
incorporation of the [99mTc(CO)3]+ core into the NOET ligand does not improve the biological features as a myocardial imaging agent.
Authors:B. Zhang, Y. Li, Q. Li, B. Ma, F. Gan, Z. Zhang, H. Cheng, and F. Yang
External-beam PIXE was used for the non-destructive analysis of early glasses unearthed from the tombs of Warring States (475–221BC) and Han Dynasty (BC 206–AD 220) in south China. It was found that these glasses were basically attributed to PbO—BaO—SiO2 system and K2O—SiO2 system. The results from the cluster analysis showed that some glasses had exactly the same recipe. The source of the K2O flux and the correlation between PbO and BaO are discussed. Some archeological information is revealed.
Authors:B. Hu, Y. Song, L. Wang, Q. Zhang, J. Li, K. Wei, Y. Chen, and L. Zhang
Electronic stopping power of 19F in Ni, Pd and Gd was measured and compared to Mstar and SRIM calculation as well as experimental results published in literature.
It turns out that the present electronic stopping power agrees reasonably well with them.
Authors:Z. Tang, S. Fu, Z. Ren, H. Zhang, Z. Yang, B. Yan, and H. Zhang
Wheat-rye 1BL.1RS translocations have been widely used in wheat breeding programs. A 1BL.1RS translocation wheat line, 91S-23, was developed from a 1R monosomic addition of the rye
inbred line L155 into wheat
MY11. A new commercial wheat cultivar, CN18, which also contained the 1BL.1RS translocation, was derived from the cross MY11 × 91S-23. Polymerase chain reaction (PCR) and fluorescence
hybridization (FISH) indicated that the rye centromere was eliminated from the 1BL.1RS chromosomes of CN18 but not from 91S-23. Based on the 1RS source and the centromeric structure of the translocation chromosome, CN18 qualifies as a new wheat cultivar possessing a 1BL.1RS translocation. CN18 displayed high yield performance and resistance to powdery mildew and stripe rust, whereas 91S-23 was susceptible to these diseases. The present study provides a new 1RS resource for wheat improvement.
Authors:B. Lin, L. Yang, H. Dai, Q. Hou, and L. Zhang
Soybean oil based polyols (5-OH polyol, 10-OH polyol and 15-OH polyol) were synthetised from epoxidized soybean oil. The melting
peak of polyols and the relationship between melting peak and the number-average functionality of hydroxyl in polyols were
investigated by differential scanning calorimetry (DSC). The thermal decomposition of polyols and some of their thermal properties
by thermogravimetry (TG) and derivative thermogravimetry (DTG) were also studied. The thermal stability of polyols in a nitrogen
atmosphere was very close hence they had a same baseplate of triglyceride for polyols. The extrapolated onset temperature
of polyols in their thermal mass loss, first step had a decreasing order: 5-OH polyol>10-OH polyol>15-OH polyol due to the
difficulty in forming multiple elements ring of them had the same order.
The thermal behavior of polyols under non-isothermal conditions using Friedman’s differential isoconversional method with
different heating rates indicated that the 5-OH polyol had the lowest activation energy in thermal decomposition amongst these
polyols according to the same fractional mass loss because of the weakest intramolecular oligomerization. The 15-OH polyol
was prior to reach the mass loss region because the six-member ring is more stable than the three-member ring from 10-OH polyol
and more easily formed.