Authors:X. Lu, X. Tian, A. Zhao, J. Cui, and X. Yang
To investigate the effect of Zn fertilization on soil Zn fractions and grain Zn concentration in wheat grown on potentially Zn-deficient soil, a field experiment was carried out. The experimental design was split plot consisted of two varieties of wheat (Zhengmai 9023 and Xinong 889) with five Zn levels (0, 7.5, 15, 30 and 45 kg Zn/ha). Results showed that Zn fertilization had no significant effect on wheat yield and grain Zn concentration, and the recovery of Zn fertilizer was only 0.06% to 0.29%. However, the amount of soil DTPA-Zn was increased by 2.3-9.8-folds as Zn supplementation increases during the whole wheat growth stage as compared to the control (Zn0 treatment). Besides, DTPA-Zn was positively correlated with both Loose organic matter bound Zn (LOM-Zn) and Exchange Zn (Ex-Zn), and their partial correlation coefficients were 0.558 and 0.119, respectively. Moreover, these two fractions also showed positive correlation with grain Zn concentration. The amount of LOM-Zn was firstly increased with increasing Zn fertilizer levels then gradually decreased as it get converted to mineral bound Zn (Min-Zn). Zn fertilization in this potentially Zn deficient soil increased the amount of DTPA-Zn in the whole wheat growth stage; however, grain Zn concentration cannot be significantly increased as Zn levels increase, thus suggesting that there are inhibitory factors for Zn absorption and translocation. Furthermore, the amount of soil DTPA-Zn perhaps cannot exactly reflect the capability of soil to supply Zn.
In this article, the enthalpy of dissolution for oxymatrine in 0.15 M citric acid solution is measured using a RD496-2000 Calvet Microcalorimeter at 36.5 °C under atmospheric pressure. The differential enthalpy (ΔdifHm) and molar enthalpy (ΔsolHm) were determined for oxymatrine dissolution in 0.15 M citric acid solution. On the basis of these experimental data and calculated results, the kinetic equation, half-life, ΔsolHm, ΔsolGm, and ΔsolSm of the dissolution process were also obtained.
Laburnine's dissolution behaviors in glucose and saline solution were studied by a micro-calorimetry method. The measured integral and differential heats of solution were utilized to build equations of the solute and the heat, so that dissolution thermodynamic equations and half-time periods, ΔsolHm, ΔsolGm, and ΔsolSm were obtained. The results show that this study does not only provide a simple method for the determination of the half-life period for a drug but also offer a theoretical reference for the clinical application of laburnine.
In this article, the enthalpies of dissolution of resveratrol in dimethyl sulfoxide (DMSO) were measured using a RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure. The differential enthalpy (ΔdifHm) and molar enthalpy (ΔsolHm) of dissolution of resveratrol in DMSO were determined, and the relationship between heat and the amount of solute was also established. Based on the thermodynamic and kinetic knowledge, the corresponding kinetic equation, half-life, ΔsolHm, ΔsolSm, ΔsolGm, the relative partial molar enthalpy (ΔsolHm(partial)) and the relative apparent molar enthalpy (ΔsolHm(app)) of the dissolution process were obtained. The results showed that this study not only provided a simple method for the determination of the half-life for a drug, but also offered a theoretical reference for the clinical application of resveratrol.
Authors:Songsheng Jiang, Zhiyuan Chang, Min Zhao, Yonggang Zhao, X. L. Zhao, and W. E. Kieser
Under an IAEA project for upgrading of reference materials, a new determination of the 129I concentration in the IAEA-375 reference material was performed. A chemical procedure was set up for the preparation of the AgI samples. Measurement of 129I was carried out using the IsoTrace Tandetron AMS facility at University of Toronto. To ensure the accuracy of the calibration, the tuning of the AMS system was iterated using not only the QC (quality control) samples but also all unknown samples. To minimize any possible current-dependent effects between 129I and 127I ions in the injection magnet, low Cs+ sputtering beam intensity (10 μA) was used. The reproducibility in determining the 129I/127I ratio in the IAEA-375 AgI samples was less than 1%. The activity concentration (CA) of 129I in the IAEA-375 reference material was determined to be 1.59±0.08 mBq . kg-1 at 95% confidence level. The present value is about 7% lower than the IAEA recommended value (1.7 mBq . kg-1) listed in 2000 or 20% lower than the recommended value (2 mBq . kg-1) listed in the IAEA AQCS Reference Material Catalogue (2002-2003). Since the IAEA recommended values for IAEA-375 materials was issued about 10 years ago and error range of the recommended values were large, the results we obtained might be useful in upgrading the recommended value.
Authors:X. Yang, X. Tian, W. Gale, Y. Cao, X. Lu, and A. Zhao
Three field experiments were conducted to determine the effect of soil Zn, foliar Zn, and soil N application on Zn and phytic acid concentrations in wheat grain grown on potentially Zn-deficient soil. Results showed significant genotypic variation in grain Zn concentrations among fifteen wheat cultivars commonly grown in northwest China. Soil Zn application had mixed effects, increasing grain Zn concentrations of some cultivars by as much as 21%, but reducing grain Zn concentrations of other cultivars by as much as 14%. In comparison, foliar Zn application increased grain Zn concentrations by 26 to 115%. Grain Zn concentrations were 14% larger in the combined (foliar Zn + soil Zn) treatment compared to the foliar Zn treatment, but the added cost of soil Zn application may not be economically justifiable. Wheat grain phytic acid concentrations and phytic acid: Zn molar ratios were less in the foliar Zn and (foliar Zn + soil Zn) treatments compared to the soil Zn and the unfertilized treatments. This indicated that foliar Zn increased Zn bioavailability. Best results were obtained when foliar Zn was applied at early grain filling. Overall, these findings indicate that foliar Zn application to Zn-efficient cultivars could reduce human Zn deficiency in regions with potentially Zn-deficient soil.
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.
The thermal behavior of rutin extracted from the buds of Sophora japonica L. by different methods and conditions have been investigated using TG and DTG. The results showed that every sample had
different mass loss, curve shape, and peak location related to varied extraction technology. The TG-DTG characteristics of
the rutin sample extracted by alkali-dissolution and acid-sedimentation with the solution adjusted to pH 9 and simply borax
as stabilizer were highly similar to that of standard rutin, with the maximal purity determined by spectrophotometry. Therefore,
the TG-DTG patterns could be served to characterize rutin extracted from the buds of Sophora japonica L.
Authors:Jungang Gao, X. Zhang, L. Huo, and H. Zhao
The curing kinetics of a bi-component system about o-cresol-formaldehyde epoxy resin (o-CFER) modified by liquid crystalline p-phenylene di[4-(2,3-epoxypropyl) benzoate] (p-PEPB), with 3-methyl-tetrahydrophthalic anhydride (MeTHPA) as a curing agent, were studied by non-isothermal differential
scanning calorimetry (DSC) method. The relationship between apparent activation energy Ea and the conversion α was obtained by the isoconversional method of Ozawa. The reaction molecular mechanism was proposed. The results show that
the values of Ea in the initial stage are higher than other time, and Ea tend to decrease slightly with the reaction processing. There is a phase separation in the cure process with LC phase formation.
These curing reactions can be described by the Šesták–Berggren (S–B) equation, the kinetic equation of cure reaction as follows:
YBaCo4O7 compound is capable to intake and release a large amount of oxygen in the temperature range of 200–400°C. In the present
study, the effect of Zn, Ga and Fe substitution for Co on the oxygen adsorption/desorption properties of YBaCo4O7 were investigated by thermogravimetry (TG) method. Due to fixed oxidation state of Zn2+ ions, the substitution of Zn2+ for Co2+ suppresses the oxygen adsorption of YBaCo4−xZnxO7. The substitution of Ga3+ for Co3+ also decreases the oxygen absorption capacity of YBaCo4−xGaxO7. This can be explained by the strong affinity of Ga3+ ions towards the GaO4 tetrahedron. Compared with Zn- and Ga-substituted samples, the drop of oxygen adsorption capacity is smallest for Fe-substituted
samples because of the similar changeability of oxidation states of Co and Fe ions.