Authors:J. Zhao, L. Zhong, L. Zou, C. Zhang, L. Peng, W. Xiao, and G. Zhao
The purpose of this study was to investigate the effects of endophytic fungi from tartary buckwheat on the host sprout growth and functional metabolite production. Without obvious changes in the appearance of the sprouts, the exogenous fungal mycelia elicitors notably stimulated the sprout growth and rutin accumulation, and the stimulation effect was mainly depended on the mycelia elicitor species along with its treatment dose. Three endophytic fungi Fat6 (Bionectria pityrodes), Fat9 (Fusarium oxysporum) and Fat15 (Alternaria sp.) were screened to be the most effective candidates for promoting F. tataricum sprout growth and rutin production. With application of polysaccharide (PS, 150 mg/l) of endophyte Fat6, PS (200 mg/l) of endophyte Fat9, and PS (150 mg/l) of endophyte Fat15, the rutin yield was effectively increased to 47.89 mg/(100 sprouts), 45.85 mg/(100 sprouts) and 46.83 mg/(100 sprouts), respectively. That was about 1.5- to 1.6-fold compared to the control culture of 29.37 mg/(100 sprouts). Furthermore, the present study revealed that the biosynthesis of the functional flavonoid resulted from the stimulation of the phenylpropanoid pathway by mycelia polysaccharide treatments. Application of specific fungal elicitors could be an efficient strategy for improving the nutritional and functional quality of tartary buckwheat sprouts.
The heat capacities of N-(tert-butoxycarbonyl)-l-phenylalanine (abbreviated to NTBLP in this article), as an important chemical intermediates used to synthesize proteins and polypeptides, were measured by means of a fully automated adiabatic calorimeter over the temperature range from 78 to 350 K. The measured experimental heat capacities were fitted to a polynomial equation as a function of temperature. The thermodynamic functions, HT − H298.15K and ST − S298.15K, were calculated based on the heat capacity polynomial equation in the temperature range of (80–350 K) with an interval of 5 K. The thermal stability of the compound was further studied using TG and DSC analyses; a possible mechanism for thermal decomposition of the compound was suggested.
Temperature programmed combustions (TPC) of Yang-Quan anthracite, Liao-Cheng lean coal and Li-Yan bituminous coal in oxy-fuel
atmosphere were conducted in a thermogravimetric analyzer and characteristic parameters were deduced from the TG-DTG curves.
The results showed that combustion got harder to progress as the coalification degree increasing. Within range of 40%, effect
of heightening O2 concentration favored the combustion process, but beyond this zone, the effect leveled off. The model-fitting mathematical
approach was used to evaluated the kinetic triplet (f (α), E, A) through Coats–Redfern method. The calculation showed that D3-Jander was the proper reaction model and the evaluations of E and A validated the experimental results.
Authors:Z. Dang, F. Zhao, S. Li, C. Yin, and R. Hu
The thermal decomposition characteristics of1,7-diazido-2,4,6-trinitrazaheptane (DATH) and multi-component systems containing
DATH were studied by using DSC, TG and DTG techniques. Three –NO2 groups in the DATH molecule break away first from the main chain when DATH is heated up to 200C. Following this process,
the azido groups and the residual molecule decompose rapidly to release a great deal of heat within a short time. In the multi-component
systems, DATH undergoes a strong interaction with the binder of the double-base propellant and a weak interaction with RDX.
The burning rates of the two propellants were determined by using a Crawford bomb. The results showed that the burning rate
rises by about 19–66% when 23.5%DATH is substituted for RDX in a minimum smoke propellant. Meanwhile, the N2 level in the combustion gases is enhanced, which is valuable for a reduction of the signal level of the solid propellant.
Authors:L. Yang, F. Xu, L. Sun, Z. Zhao, and C. Song
Microcalorimetry was applied to study the effect of cephalosporins (cefazolin sodium and cefonicid sodium) on the E. coli growth. The microbial activity was recorded as power-time curves through an ampoule method with a TAM Air Isothermal Microcalorimeter
at 37°C. The parameters such as the growth rate constant (k), inhibitory ratio (I), the maximum power output (Pm) and the time corresponding to the maximum power output (tm) were calculated. The change tendencies of k, with the increasing of concentration (C) of the two cephalosporins, are similar which show that cefazolin sodium and cefonicid sodium have the same inhibitory mechanism.
The experimental results reveal that cefonicid sodium has a stronger antibacterial activity towards E. coli than that of cefazolin sodium and this was coincide with the clinical manifestations.
Authors:L. Zhao, J. Ge, C. Qiao, H. Zhang, and S. Jiang
A high-performance liquid chromatographic (HPLC) method has been developed for separation and quantitative analysis of flavonoid aglycones in Rhododendron anthropogonosides Maxim. Flavonoids in their bound forms were hydrolyzed with acid before HPLC analysis. Analytical samples were pretreated by solid-phase extraction on C18 reversed-phase cartridges. Optimum separation on a 4.6 mm × 250 mm i.d. C18 column was achieved by use of a 52:48 (v/v) mixture of methanol and an aqueous solution of 10 mm citric acid and 1 mm sodium dodecyl sulfate as mobile phase. The flow rate was 1.0 mL min–1 and the detection wavelength 360 nm. Five flavonoids, myricetin, quercetin, luteolin, kaempferol, and isorhamnetin, were separated with high resolution without use of gradient elution. The method was successfully used for efficient quality-control analysis by quantifying flavonoids in R. anthopogonosides. Repeatability tests showed that intra-day and inter-day RSD was <10%. LOD of the five flavonoids were <0.85 μg mL–1. Recovery ranged from 90.2 to 112.5%, with RSD <11.1%.
Authors:C. Liu, Y. Zhao, S. Li, H. Teng, and Z. Wang
The concentration of radon in an underground research facility (URF) was measured by setting up 12 sampling points in the
URF and with 3 different measurement methods. All the methods were calibrated in the radon laboratory of the No. 6 Institute
of Nuclear Industry. The accumulation of radon in the URF was observed before a ventilation system was applied. The reduction
of radon concentration in the URF by 1-hour ventilation was also observed. Experimental result indicates that the concentration
of radon in the URF increased from 15 to 50 Bq·m−3 in 5 days without ventilation, and decreased to less than 10 Bq·m−3 with 1-hour ventilation. Applying the average working time of 4 hours per day of the workers in the URF, the additional effective
dose is 0.75 msv·y−1 when 1 hour ventilation is applied before entering the URF and 13 mSv·y−1 without ventilation. These figures strongly suggest that for the health of the workers, ventilation in such underground research
facilities is needed.
Authors:Z. Dang, L. Fan, Y. Shen, C. Nan, and S. Zhao
Different scanning calorimetry and dynamic mechanical analysis are used to study the thermal behavior of composites by melt-mixing
low-density polyethylene (LDPE) matrix and zinc oxide whisker (ZnOw) fillers. Micrographs of the composites illustrate that needle or wedge shaped ZnOw are distributed uniformly in the LDPE matrix. Dielectric properties of the composites are measured in a frequency range of
1-10 MHZ. The results show that the addition of ZnOw does not affect the melting behavior of LDPE, but has an important effect on the heat of fusion, dynamic mechanical behavior,
and dielectric behavior of the composites.
Authors:C. Zhang, Y. Zhao, S. Feng, C. Qi, Z. Fu, F. Guo, and R. Wang
To increase the tumor uptake of Val-Gly-Gly (VGG), adenine was introduced into the peptide. N-mercaptoacetyl-VGG-adenine (MAVGG-adenine)
and MAVGG were labeled with 99mTc using a solution of SnCl2 and tartaric acid as reducing agent. Biodistribution in mice bearing the S180 tumor was measured and γ imaging was performed.
Compared with MAVGG, adenine conjugated MAVGG had higher tumor uptake and tumor to normal tissue ratios, which suggested that
the tumor uptake property of a peptide may be improved by introducing a nucleotide base. The high contrasted tumor images
of 99mTc-MAVGG-adenine also suggested its potential utility as tumor imaging agent.
Authors:Y. Zhao, C. Zhang, C. Qi, S. Feng, G. You, Z. Fu, F. Guo, and R. Wang
Two peptide ligands conjugated adenine, [9-N-(tritylmercapto acetyl diglycyl aminoethyl) adenine, Tr-MAG2-Ade] and [9-N-(tritylmercapto acetyl triglycyl aminoethyl) adenine, Tr-MAG3-Ade], are synthesized and labeled with 99mTc by directly labeling method. The stability of 99mTc-MAG2-adenine and 99mTc-MAG3-adenine in vitro is measured. The uptake radios of tumor to muscle at 3h post-injection are 5.70 and 4.92, respectively.
The biodistribution and scintigraphic imaging studies show that the two complexes have high localization in tumor and high
contrasted tumor images can be obtained, which suggest their potential utility as tumor imaging agents. But the high radioactivity
of abdomen could prevent the tumor imaging in this area.