A two-year field experiment with a split-split plot design was conducted to investigate the effects of soil N(0, 120 and 240 kg N·ha−1) and foliar Zn applications at different growth stages (jointing, flowering, early grain filling, and late grain filling) on Zn translocation and utilization efficiency in winter wheat grown on potentially Zn-deficient soil. Our results showed that foliar Zn application at the early grain filling stage significantly increased the Zn concentration in the grain (by 82.9% compared to control) and the Zn utilization efficiency (by 49% compared to jointing). The Zn concentration in the straw consistently increased with the timing of the foliar Zn application and was highest at late grain filling. However, the timing of the Zn application had little effect on Zn uptake in the grain and straw. A high N supply significantly increased the Zn concentration in and uptake by grain and straw, but it had little effect on the efficiency of Zn utilization. Consequently, a foliar Zn application at early grain filling causes Zn to re-translocate into grain from vegetative tissues, resulting in highly nutritional wheat grain. Finally, these practices improved the efficiency of Zn utilization in winter wheat and led to Zn-enriched straw, which may contribute to Zn recycling if it is returned to the field. The results also indicated that N nutrition is a critical factor in both the concentration and translocation of Zn in wheat.
Authors:D-Y Zhao, Q-Q Qi, X Long, X Li, F-X Chen, Y-B Yu, and X-L Zuo
Impaired intestinal barrier function has been demonstrated in the pathophysiology of diarrhea-predominant irritable bowel syndrome (IBS-D). This study aimed to describe the intestinal ultrastructural findings in the intestinal mucosal layer of IBS-D patients.
In total, 10 healthy controls and 10 IBS-D patients were analyzed in this study. The mucosa of each patient’s rectosigmoid colon was first assessed by confocal laser endomicroscopy (CLE); next, biopsied specimens of these sites were obtained. Intestinal tissues of IBS-D patients and healthy volunteers were examined to observe cellular changes by transmission electron microscopy (TEM).
CLE showed no visible epithelial damage or inflammatory changes in the colonic mucosa of IBS-D compared with healthy volunteers. On transmission electron microscopic examination, patients with IBS-D displayed a larger apical intercellular distance with a higher proportion of dilated (>20 nm) intercellular junctional complexes, which was indicative of impaired mucosal integrity. In addition, microvillus exfoliation, extracellular vesicle as well as increased presence of multivesicular bodies were visible in IBS-D patients. Single epithelial cells appeared necrotic, as characterized by cytoplasmic vacuolization, cytoplasmic swelling, and presence of autolysosome. A significant association between bowel habit, frequency of abdominal pain, and enlarged intercellular distance was found.
This study showed ultrastructural alterations in the architecture of intestinal epithelial cells and intercellular junctional complexes in IBS-D patients, potentially representing a pathophysiological mechanism in IBS-D.
This paper presents calorimeter measurement for the thermal decomposition of n-propyl nitrate (NPN), isopropyl nitrate (IPN) and 2-ethylhexyl nitrate (EHN). Similar experimental results of triethylene
glycol dinitrate (tri-EGDN) and tetraethylene glycol dinitrate (tetra-EGDN) are included for comparison. The potential energy
surfaces (PESs) along O-NO2 bond stretch are investigated using the DFT (B3P86, B3PW91 and B3LYP), ab initio Hartree-Fock and PM3 methods. The good coincidence
of experimental with theoretical results indicates that initial stage in the thermal decomposition of five nitrates is only
unimolecular homolytical dissociation of the O-NO2 bonds and the activation energies of thermolysis by DSC correspond to the energies of O-NO2 bond scission of nitrates.
Authors:Q. Wang, J. Sun, G. Chu, X. Yao, and C. Chen
The thermal behaviors of four organic solvents with/without LiPF6 were measured by C80 microcalorimeter at a 0.2�C min−1 heating rate. With the addition of 1 M LiPF6, the ethylene carbonate (EC) and propylene carbonate (PC) show the exothermic peaks at elevated temperature, which lessen
their stabilities. The exothermic peak temperatures of EC and PC based LiPF6 solutions are at 212 and 223�C, respectively, in argon filled vessel. However, two endothermic peak temperatures were detected
in diethyl carbonate (DEC) based LiPF6 solution at 182 and 252.5�C, respectively, in argon filled vessel. Dimethyl carbonate (DMC) based LiPF6 solution shows two endothermic peak temperatures at 68.5 and 187�C in argon filled vessel at elevated temperature. Consequently,
it is concluded that LiPF6 play a key role in the thermal behavior of its organic solution.
57Co was produced with high pure nature iron irradiated by 8.5MeV deuterons. TBP-benzene extraction method and anion-exchange method were used to separate and purify it. The purified57Co was prepared into standard solution of about 30 to 50 g Co2+/ml carrier concentration and about 0.1 mol/l HCl. The specific activity of the standard solution was measured with 4
(ppc)- coincidence counting method. The final result was 476.82(1±0.42%)Bq/mg.
The thermal stability of lithium-ion battery cathode could substantially affect the safety of lithium-ion battery. In order
to disclose the decomposition kinetics of charged LiCoO2 used in lithium ion batteries, thermogravimetric analyzer (TG) and C80 microcalorimeter were employed in this study. Four
stages of mass losses were detected by TG and one main exothermic process was detected by C80 microcalorimeter for the charged
LiCoO2. The chemical reaction kinetics is supposed to fit by an Arrhenius law, and then the activation energy is calculated as Ea=148.87 and 88.87 kJ mol−1 based on TG and C80 data, respectively.
Authors:S. Chen, X. Yang, Sh. Gao, R. Hu, and Q. Shi
The solid complexes of Cr(NO3)3 with L-α-amino acids (AA=Val, Leu, Thr, Arg, Phe and Try) have been prepared in 95% alcoholic, the compositions of which were identified as the general
formula Cr(AA)2(NO3)32H2O by elemental and chemical analyses. The bonding characteristics of the title complexes were characterized by IR, indicating
that nitrogen and oxygen atoms in the ligands coordinated to Cr3+ in a bidentate fashion. With the aid of TG-DTG and IR techniques, the complexes were subjected to thermal decomposition in
an atmosphere of oxygen, presuming that the decompositions of the complexes consist of two steps and the complexes were decomposed
into chromium hemitrioxide after undergoing dehydration and skeleton splitting of the complexes. The constant volume energies
of combustion of the complexes were determined by a RBC-P type rotating-bomb calorimeter. According to Hess's law, the standard
enthalpies of formation of the complexes were calculated as (-1831.404.40), (-2542.036.13), (-1723.813.99), (-2224.313.02),
(-2911.616.53) and (-659.327.42) kJ mol-1, respectively.
A novel thermokinetic research method for determination of rate constants of simple-order reaction in batch conduction calorimeter
under isothermal condition, the characteristic parameter method, is proposed in this paper. Only needing the characteristic
time parameter tm obtained from the measured thermoanalytical curve, the kinetic parameters of reactions studied can be calculated
conveniently with this method. The saponifications of ethyl propionate and ethyl acetate in aqueous ethanol solvent, the polymerization
of acrylamide in aqueous solution, the ring opening reaction of epichlorohydrin with hydrobromic acid have been studied. The
experimental results indicate that the characteristic parameter method for simple-order reaction is correct.
Thermal decomposition of N,N′-diphenylguanidine (DPG) was investigated by simultaneous TG/DSC-FTIR techniques under nonisothermal conditions. Online FTIR measurements illustrate that aniline is a major product of DPG decomposition. The observation that the activation energy depends on the extent of conversion indicates that the DPG decomposition kinetics features multiple processes. The initial elimination of aniline from DPG involves two pathways because of the isomerization of DPG. Mass spectrometry and thin film chromatography suggest that there are two major intermediate products with the major one of C21N3H17. The most probable kinetic model deduced through multivariate nonlinear regression method agrees well with the experimental data with a correlation coefficient of 0.9998. The temperature-independent function of conversion f(α), activation energy E and the pre-exponential factor A of DPG decomposition was also established through model-fitting method in this research.
A novel complex, [Pr(5-nip)(phen)(NO3)(DMF)]
(5-nip: 5-nitroisophthalic acid; phen: 1,10-phenanthroline, DMF: N,N-dimethylformamide),
was prepared and characterized by single crystal X-ray diffraction, elemental
analysis, IR spectrum and DTG-DSC techniques. The results show that the crystal
is monoclinic, space group P2(1)/n with a=11.0876(6) Å, b=12.8739(7)
Å, c=16.9994(8) Å; β=91.193(4)°, Z=4, Dc=1.822
Mg m–3, F(000)=1320.
Each Pr(III) ion is nine-coordinated by one chelating bidentate and two monodentate
bridging carboxylate groups, one chelating bidentate nitryl group, one DMF
molecule and one 1,10-phenanthroline molecule. The complex is constructed
with one-dimensional ribbons featuring dinuclear units and the one-dimensional
ribbons are further assembled into two-dimensional networks by strong π–π
stacking interactions. The complex has high stability up to 500°C. The
enthalpy change of formation of the compound in DMF was measured using an
RD496-III type microcalorimeter with the value of –9.214±0.173