[Effect of reduced nitrogen fertilization on carbon footprint in spring maize-late rice production system]. / 减氮施肥对春玉米-晚稻生产系统碳足迹的影响.

With the growing concerns on global climate change and food security, low carbon agriculture in food production attracts more attention. Low carbon agriculture needs to balance higher-level crop yields and lower greenhouse gas emission in production process. Improving nitrogen mana-gement may help mitigate greenhouse gas emission and achieve stable or higher crop yields in crop production systems. In this study, we investigated the effects of nitrogen application rates (150, 225, 300 kg N·hm-2) on the carbon footprint of spring maize-late rice rotation system in paddy field using the life cycle assessment. The results showed that greenhouse gas emission and carbon footprint increased with the nitrogen fertilizer application rates in both crops. Nitrogen fertilizer was the most important contributor to carbon footprint of spring maize ecosystem, accounting for 36.2%-50.2%. Methane emission increased with nitrogen fertilizer input and contributed the most to the carbon footprint of late rice production, accounting for 42.8%-48.0%. When the nitrogen application rate was reduced by 25% (225 kg N·hm-2) and 50% (150 kg N·hm-2), greenhouse gas emission of maize production decreased by 21.9% and 44.3%, and the carbon footprint decreased by 20.3% and 39.1%, respectively. Meanwhile, the greenhouse gas emissions of late rice decreased by 12.3% and 20.4%, and the carbon footprint of late rice decreased by 13.7% and 16.7%, respectively. The reduction of nitrogen fertilizer rate had no significant effect on maize yield, with the treatment of 225 kg N·hm-2 rate holding the highest yield in late rice ecosystem. The treatment of 150 kg N·hm-2 rate in spring maize production and 225 kg N·hm-2 rate in late rice production was the sustainable N fertilizer application rate for achieving high grain yield and reducing the carbon footprint in crop system.

[MgO-Biochar for the Adsorption of Phosphate in Water].

A novel composite material MgO-biochar (MgO-BC) with the peanut shells as the precursors was successfully fabricated by loading magnesium oxide (MgO) on the surface of biochar (BC) at high temperature and in oxygen-limited atmosphere. The adsorption characteristics of the resultant adsorbent toward phosphate from aqueous solution were investigated by evaluating the influences of pH, contact time and coexisting ions. The results showed that the best phosphate adsorption onto MgO-BC happened in the pH range of 7-9, and strong acidic or basic media was unfavorable to the phosphate adsorption. Phosphate adsorption process could reach equilibrium within 540 min, and the kinetics curve could be well fitted by both pseudo-first and pseudo-second models. The related coefficients were 97.3% and 99.0%. MgO-BC exhibited highly selective capacity toward phosphate in the presence of competing Cl-, HCO3- and NO3- at 10 times higher concentration than the phosphate concentration. In addition, phosphate adsorption onto MgO-BC could be described satisfactorily by Langmuir model with a fitting coefficient of higher than 99%, and the maximal adsorption capacity calculated by Langmuir equation was 138.07 mg·g-1. The adsorption capacity of phosphate by MgO-BC was much higher than the unmodified BC and other biochar-based sorbents. Furthermore, the composite material after the adsorption of phosphate could also be used as a fertilizer into the soil. It achieved the reuse of the discarded phosphate. All the results validated that MgO-BC has a wide application prospect for the phosphate cleanup from the actual wastewater.

Tuning sub-10 nm single-phase NaMnF3 nanocrystals as ultrasensitive hosts for pure intense fluorescence and excellent T1 magnetic resonance imaging.

We report ultrasensitive sub-10 nm NaMnF(3) nanocrystals codoped with Yb(3+), Er(3+)/Tm(3+) ions, and their intense pure red and near-infrared upconversion emissions in the presence of Mn(2+). The nanocrystals showed excellent T(1) contrast in 7 T MRI, implying their potential as single-phase contrast agents for fluorescent deep tissue and MR imaging.

[Polymorphic analysis of two Y chromosome short tandem repeat loci in Chinese Chengdu Han population].

OBJECTIVE: To reveal the distribution of genetic polymorphism of two novel Y chromosome short tandem repeat (Y-STR) loci (DYS508, DYS516) in Chinese Chengdu Han population. METHODS: Two Y-STR loci were amplified with PCR. The products of PCR were analyzed with polyacrylamide gel electrophoresis. Each allele of these 2 Y-STR loci was sequenced and the allele ladders were constructed. Alleles of these Y-STR loci were nominated according to recommendations of the International Society of Forensic Genetics (ISFG). RESULTS: Six and 6 alleles were observed in loci DYS508 and DYS516 respectively. The gene diversity of DYS508 and DYS516 was 0.7242 and 0.7931 respectively. The diversity of haplotype for these Y-STR loci was 0.9397. The value of discrimination power and the exclusion chance of paternity for these Y-STR loci were same as the value of haplotype diversity. CONCLUSION: Both Y-STR loci are high genetic polymorphic. They are beneficial to the test of male-female mixtures and paternity identification in forensic science.

Synthesis and characterization of sub-10 nm Platinum Hollow Spheres as electrocatalyst of direct methanol fuel cell.

Platinum Hollow Spheres (PHSs) with diameters less than 10 nm were successfully synthesized by using Co as a sacrificial template and H2PtCl6 as an oxidizing agent at 95 degrees C. The formation of PHSs at this temperature was not affected by citrate reduction and mainly depended on the pH. The results of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the platinum hollow sphere was mainly constructed by fcc (face cubic center) platinum with tiny crystallites on the shell. The performance of PHSs for methanol electro-oxidation was evaluated and compared with commercial E-TEK platinum black. Electrochemical measurement by cyclic voltammetry (CV) demonstrated that the electrochemical surface area of PHSs was about twice higher than E-TEK platinum black. Therefore, the synthesized PHSs had higher electrocatalytic activity for methanol electro-oxidation.