In-depth understanding of the effects of different molecular weight pullulan interacting with protein and starch on dough structure and application properties.

This work clarified the positive effects of pullulan on dough structure and application properties varied with its molecular weight. Pullulan with different molecular weights were introduced into dough system to explore their intervention effects on structural and technological properties of dough as well as physical and digestion properties of biscuits. Results showed that HPL (pullulan with molecule weight of 100- 300 kDa) could increase the intermolecular collisions, prompt the protein aggregation and limit the water migration in dough system, resulting in an integrate, continuous and dense network structure of the gel with strengthened elasticity and weakened extensibility, which caused an increase in biscuit thickness, hardness and crispness. On the contrary, LPL (pullulan with molecule weight of 3- 100 kDa) could go against the formation of stable and elastic dough through breaking down cross-linkage between protein and starch so as to provide biscuits with decreased hardness and crispness during baking. Both HPL and LPL delayed starch pasting and retrogradation process while HPL had the stronger retarding effect on starch digestibility of biscuits than LPL. These findings dedicated to a better understanding of pullulan function in dough system and provide suggestions for fractionation applications of pullulan in food field.

[Analysis of the Composition of Atmospheric Fine Particles (PM2.5) Produced by Burning Fireworks].

Burning fireworks is one of the sources of atmospheric fine particles (PM2.5). The Chinese Spring Festival in Quanzhou City was taken as an example to study the effects of burning fireworks on the occurrence of PM2.5, and provide information on protection against air pollution caused by special pollution sources. The results showed that the concentrations of SO2, PM10, and PM2.5 increased appreciably, and the concentration of PM2.5 increased most significantly during the fireworks burning period. The peak daily average concentration in the urban area was about 4 times the annual average concentration in the urban area. The peak value of the hourly average concentration of PM2.5 in the Tushan Street station was about 21 times the annual average concentration in the urban area. At the peak of the discharge, the ratios of the characteristic elements of fireworks, such as Al, Mg, Ba, Cu, and Sr, increased rapidly, and the hourly number concentrations of Al+, Mg+, Ba+, and Cu+ were highly correlated. During the monitoring period, the main pollution sources of fine particles in Quanzhou City were fireworks and biomass burning, which accounted for more than half of the total particulate matter. The proportion of pollutants originating from coal-based and industrial process sources were relatively low, and both of them accounted for less than 10.0% of the particulate matter. The concentration of PM2.5 was up to 0.578 mg·m-3 during the fireworks burning period, the rate of contribution by fireworks increased to 58.2%. Analysis of the pollution process showed that the changes in the concentration of PM2.5 have a similar trend with the number concentration and the ratio of fireworks burning. The results indicated that the main reason of the deterioration of the atmospheric environment during the Chinese Spring Festival in Quanzhou is the centralized discharging of fireworks.

Impacts of biochar and oyster shells waste on the immobilization of arsenic in highly contaminated soils.

Soil contamination is a serious problem with deleterious impacts on global sustainability. Readily available, economic, and highly effective technologies are therefore urgently needed for the rehabilitation of contaminated sites. In this study, two readily available materials prepared from bio-wastes, namely biochar and oyster shell waste, were evaluated as soil amendments to immobilize arsenic in a highly As-contaminated soil (up to 15,000 mgAs/kg). Both biochar and oyster shell waste can effectively reduce arsenic leachability in acid soils. After application of the amendments (2-4% addition, w/w), the exchangeable arsenic fraction decreased from 105.8 to 54.0 mg/kg. The application of 2%biochar +2% oyster shell waste most effectively reduced As levels in the column leaching test by reducing the arsenic concentration in the porewater by 62.3% compared with the treatment without amendments. Biochar and oyster shell waste also reduced soluble As(III) from 374.9 ± 18.8 µg/L to 185.9 ± 16.8 µg/L and As(V) from 119.8 ± 13.0 µg/L to 56.4 ± 2.6 µg/L at a pH value of 4-5. The treatment using 4% (w/w) amendments did not result in sufficient As immobilization in highly contaminated soils; high soluble arsenic concentrations (upto193.0 µg/L)were found in the soil leachate, particularly in the form of As(III), indicating a significant potential to pollute shallow groundwater aquifers. This study provides valuable insights into the use of cost-effective and readily available materials for soil remediation and investigates the mechanisms underlying arsenic immobilization in acidic soils.

Synthesis, structure, photophysics and electrochemiluminescence of Re(I) tricarbonyl complexes with cationic 2,2-bipyridyl ligands.

Two water soluble Re(I) tricarbonyl diimine complexes containing cationic 2,2'-bipyridyl ligands [Re(L1)(CO)(3)(AN)](2+) (1) and [Re(L2)(CO)(3)(AN)](3+) (2) (L1 and L2: a cationic 2,2'-bipyridyl ligand, AN: acetonitrile) were synthesized and characterized. Their photophysical, electrochemical and electrochemiluminescent properties were investigated. The crystal structures of the two complexes have also been determined. Electrochemiluminescence (ECL) of the two complexes 1 and 2 have been studied in aqueous buffer solution in the presence of co-reactant tri-n-propylamine (TPrA) or 2-(dibutylamino)ethanol (DBAE) at a Au working electrode. The ECL behavior of the complexes was also studied in the presence of several surfactants such as Triton X-100 and Zonyl FSN. The ECL signals of the rhenium(I) complex were enhanced about 190-fold and 70-fold at a Au electrode in the presence of Triton X-100 for the [Re(L1)(CO)(3)(AN)](2+)/TPrA and [Re(L1)(CO)(3)(AN)](2+)/DBAE systems, respectively.