Radiobrominations of cetyl bromide with82Br in several organic media such as DMF, 18-crown-6, DMSO, pyridine and n-butanol were achieved and a comparison was made as to the labelling rates. The rate order was found as follows: DMF>18-crown-6>DMSO>pyridine } n-butanol which was attributed to increased anion /i.e., the nucleophilic bromide ion,82Br–/ solvation. Labelling in pyridine or alcohol was found to be too slow to meet practical needs. A suitable crown ether such as 18-crown-6 was found to be favourable for rapid radiobromination. However, it was discovered unexpectedly that dimethylformamide /DMF/ was superior to 18-crown-6. We therefore recommend DMF as an alternative reaction medium for fast radiobromination considering that this solvent is inexpensive and readily available.
The extraction of U(VI) with newly synthesized alkylamide, N,N-diethyloctadecanamide (DEODA), has been studied. The dependence of the extraction on nitric acid concentration, DEODA concentration and temperature from nitric acid solution has been considered. The extracted species has also been investigated using FT-IR spectrometry. The related themodynamic functions were calculated.
We establish a sharp estimate for some multilinear operator related to Bochner--Riesz operator. As an application, we obtain the weighted norm inequality and L log L type estimate for the multilinear operator.
Authors:B. Liu, Z. Tan, Z. Nan, P. Liu, L. Sun, F. Xu, and X. Lan
A solid complex of rare-earth compounds with alanine, [ErY(Ala)4(H2O)8](ClO4)6 (Ala=alanine), was synthesized, and a calorimetric study and thermal analysis for it was performed through adiabatic calorimetry
and thermogravimetry. The low-temperature heat capacity of [ErY(Ala)4(H2O)8](ClO4)6 was measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. A solid-solid
phase transition was found between 99 and 121 K with a peak temperature at 115.78 k. The enthalpy and entropy of the phase
transition was determined to be 1.957 Kj mol-1, 16.90 j mol-1 k-1, respectively. Thermal decomposition of the complex was investigated in the temperature range of 40~550C by use of the thermogravimetric
and differential thermogravimetric (TG/DTG) analysis techniques. The TG/DTG curves showed that the decomposition started from
120 and ended at 430C, completed in three steps. A possible mechanism of the thermal decomposition was elucidated.
Authors:H. Wang, D. Cao, W. Chen, D. Liu, B. Liu, and H. Zhang
Wheat kernel morphology is a very important trait for wheat yield improvement. This is the first report of association analysis of kernel morphology traits in wheat breeding lines. In Qinghai, China, the research described here involved genome-wide association analysis in breeding lines derived from synthetic hexaploid wheat with a mixed linear model to identify the quantitative trait loci (QTLs) related to kernel morphology. The 8033 effective Diversity Array Technology (DArT) markers produced a genetic map of 5901.84 cM with an average density of 1.36 markers/cM. Population structure analysis classified 507 breeding lines into three groups by Bayesian structure analysis using unlinked markers. Linkage disequilibrium decay was observed with a map coverage of 2.78 cM. Marker-trait association analysis showed that 15 DArT markers for kernel morphology were detected, located on nine chromosomes, and explained 2.6%–4.0% of the phenotypic variation of kernel area (KA), kernel width (KW), kernel length (KL) and thousand-kernel weight (TKW). The marker 1139297 was related to both the KL and KA traits. Only six DArT markers were close to known QTLs. The parent SHW-L1 carried eight favored alleles, while other seven favored alleles were derived from elite common wheat cultivars. These QTLs, identified in elite breeding lines, should help us understand the kernel morphology trait better, and to provide germplasm for breeding new wheat cultivars for Qinghai Province or other regions.
Authors:X. Geng, H. Gao, B. Wang, A. Liu, and X. Feng
Both calorimetric determination of displacement adsorption enthalpies ΔH and measurement of adsorbed amounts of lysozyme (Lyz) denatured by 1.8 mol L−1 guanidine hydrochloride (GuHCl) on a moderately hydrophobic packings at 298 K, pH 7.0 and various salt concentrations were
carried out. Based on the thermodynamics of stoichiometric displacement theory (SDT) the fractions of thermodynamic functions,
which related to four subprocesses of denatured protein refolding on the surface, were calculated and thermodynamic analysis
that which one of the subprocesses plays major role for contribution to the thermodynamic fractions was made in detail. The
moderately hydrophobic surface can provide denatured Lyz energy and make it gain more conformation with surface coverage or
salt concentration increment. The displacement adsorptions of denatured Lyz onto PEG-600 surface are exothermic, more structure-ordered
and enthalpy driven processes.
Authors:B. Liu, P. Thomas, A. Ray, and J. Guerbois
of MgO obtained from calcination of magnesium carbonate at different temperatures
has been investigated by means of hydration in a constant relative humidity
environment at 40°C for periods up to 24 days. Natural magnesite and AR
grade basic MgCO3 calcined in the range of 500–1000°C
was characterised in terms of surface area, crystallite size, morphology,
and hydration rate.
It was found that the hydration rate is dependent
on the surface area and crystallite size where temperature was the main variable
affecting them. The most reactive MgO was produced at the lowest calcination
temperature with the highest surface area and the smallest crystallite size.
The basic MgO specimens showed higher degree of hydration compared to the
natural MgO specimens due to the smaller surface area and larger crystallite
size. The low MgO content of the starting natural magnesite is also attributable
to the lower reactivity. This preliminary study serves as a mean to investigate
potential utilisation of reactive MgO as a supplementary cementitious material
in eco-friendly cements.
Authors:B. Liu, P. Thomas, A. Ray, R. Williams, and S. Donne
The thermal decomposition of electrolytic
manganese dioxide (EMD), in an inert atmosphere, and the effect of chemical
reduction on EMD, using 2-propanol under reflux (82C), was investigated
by differential scanning calorimetry (DSC). This study is an extension of
a study investigating the thermal decomposition of EMD and reduced EMD by
TG-MS (J. Therm. Anal. Cal., 80 (2005)625)). The DSC characterisation was
carried out up to 600C encompassing the water loss region up to 390C
and the first thermal reduction step. Water removal was observed in two distinct
endothermic peaks (which were not deconvolved in the TG-MS) associated with
the removal of bound water. For the lower degrees of chemical reduction, thermal
reduction resulted in the formation of Mn2O3;
for higher degrees of chemical reduction, the thermal reduction resulted in
Mn3O4 at 600C. In the DSC
the thermal reduction of the EMD and chemically reduced specimen was observed
to be endothermic. The reduced specimens, however, also showed an exothermic
A fully automated adiabatic calorimeter controlled on line by a computer used for heat capacity measurements in the temperature
range from 80 to 400 K was constructed. The hardware of the calorimetric system consisted of a Data Acquisition/Switch Unit,
34970A Agilent, a 7 1/2 Digit Nano Volt /Micro Ohm Meter, 34420A Agilent, and a P4 computer. The software was developed according
to modern controlling theory. The adiabatic calorimeter consisted mainly of a sample cell equipped with a miniature platinum
resistance thermometer and an electric heater, two (inner and outer) adiabatic shields, two sets of six junction differential
thermocouple piles and a high vacuum can. A Lake Shore 340 Temperature Controller and the two sets of differential thermocouples
were used to control the adiabatic conditions between the cell and its surroundings. The reliability of the calorimeter was
verified by measuring the heat capacities of synthetic sapphire (α-Al2O3), Standard Reference Material 720. The deviation of the data obtained by this calorimeter from those published by NIST was
within ±0.1% in the temperature range from 80 to 400 K.
Authors:B. Liu, P. Thomas, A. Ray, and R. Williams
The effect of sampling conditions on the decomposition of electrolytic manganese dioxide using thermal methods is reported.
Significant differences were observed in the mechanism of the decomposition by simply changing the reaction environment from
a closed pan to an open pan configuration. The purge gas atmosphere was also observed to influence the decomposition mechanism.
As a product of the decomposition is oxygen, the change in the mechanism observed between the experimental conditions may
be explained in terms of the ease of removal of oxygen from the reaction site.