Search

New food packaging has shown research significance in the face of increasing demand for high-quality foods and growing attention paid to food safety. In this study, ginger essential oil microcapsule composite films were prepared by combining microcapsules prepared by a complex coacervation method with gelatin films, and the mechanical properties and active functions of the composite films were analyzed. Fourier-transform infrared spectroscopy and differential scanning calorimetry confirmed the successful encapsulation of ginger essential oil. The scanning electron microscopy of the composite films showed the microcapsules and gelatin film matrix were highly compatible. During the entire storage period, the antioxidant capacity of the ginger essential oil microcapsule films weakened more slowly than ginger essential oil microcapsules and could be maintained at a relatively high level for a long time. The microcapsule films had excellent inhibitory effects on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. Therefore, the direct addition of microcapsules to a film matrix can broaden the application range of microcapsules and increase the duration of the release of active ingredients. Ginger essential oil microcapsule films are potential biodegradable food packaging films with long-lasting activity.

Effective separation and fast transport of photogenerated carriers are vital links determining the photocatalytic performance. Heterostructure constructed by two complementary semiconductors is a feasible strategy to achieve this goal. By one‐pot hydrothermal method, 0D‐TiO2 nanoparticles are loaded onto 2D‐CuGaO2 nanosheets, forming a mixed dimension, closely combined heterostructure. The photocurrent density of CuGaO2/TiO2 heterostructure is ∼16.6 μA/cm2, which is 1.24 times higher than that of pristine CuGaO2 nanosheets (∼13.4 μA/cm2) and 15 times higher than that of TiO2 (∼1.1 μA/cm2). In the tetracycline hydrochloride degradation experiment, the degradation efficiency of tetracycline hydrochloride by CuGaO2/TiO2 heterostructure reached 99% within 90 min, which was 1.2 times the degradation efficiency of CuGaO2 nanoparticles (82%) and 20.2 times the degradation rate of TiO2 (4.9%). A series of experimental characterizations combined with density functional theory calculations revealed that it is the built‐in electric field in the CuGaO2/TiO2 interface region that drives the photogenerated electron–hole pairs to travel in the opposite direction, thus inhibiting their recombination. Furthermore, the energy band offset of the CuGaO2/TiO2 interface makes it easier for the photogenerated holes and electrons to gather onto the valence band of the CuGaO2 nanosheets and the conduction band of the TiO2 nanoparticles, respectively. Therefore, appropriate interface lattice matching, suitable configuration of band gap and band edge positions, and strong opposite drive of interface electric field enable CuGaO2/TiO2 heterostructure to achieve wide spectral response and effective separation of photogenerated electron–hole pairs at the same time. [ABSTRACT FROM AUTHOR]

Constructing the hetrostructure is a feasible strategy to enhance the performances of photocatalysts. However, there are still some fundamental details and mechanisms for the specific design of photocatalysts with heterostructure, which need further confirming and explain. In this work, g-C3N4-based heterostructures are constructed with TiO2 in different ways, and their intrinsic factors to improve the photocatalytic activity are systematically studied by density functional theory (DFT). When g-C3N4 combines horizontally with TiO2 to form a heterostructure, the interaction between them is dominated by van der Waals interaction. Although the recombination of photo-generated electron–hole pair cannot be inhibited significantly, this van der Waals interaction can regulate the electronic structures of the two components, which is conducive to the participation of photo-generated electrons and holes in the photocatalytic reaction. When the g-C3N4 combines vertically with TiO2 to form a heterostructure, their interface states show obvious covalent features, which is very beneficial for the photo-generated electrons' and holes' transport along the opposite directions on both sides of the interface. Furthermore, the built-in electric field of g-C3N4/TiO2 heterostructure is directed from TiO2 layer to g-C3N4 layer under equilibrium, so the photo-generated electron–hole pairs can be spatially separated from each other. These calculated results show that no matter how g-C3N4 and TiO2 are combined together, the g-C3N4/TiO2 heterostructure can enhance the photocatalytic performance through corresponding ways. [ABSTRACT FROM AUTHOR]

Composite photocatalyst with heterostructure is often recognized as an effective strategy to achieve efficient charge separation and increase carrier concentration. In this study, the (1 1 0) and (1 0 1) surfaces of TiO 2 and SnO 2 were chosen to construct the abrupt and graded TiO 2 /SnO 2 hetero-structures. The interface properties and band offsets of four heterostructures are calculated and analyzed in detail. It was found that the graded heterostructures are more stable and easier to preparation than the abrupt heterostructures, the charge depletion and accumulation occur at both ends of the transition layer. The interfacial electric field caused by this effect allows the photo-generated electron-hole pairs to be easily separated and transferred in the opposite direction at the interface, which is important for improving the photocatalytic activity. In addition, the intrinsic mechanism of the four hetero-structures is discussed according to the analysis of the band offset, which belongs to the type II heterostructures. For TiO 2 /SnO 2 -(1 1 0) heterostructure, the photo-generated electrons transfer from the conduction band of TiO 2 to the conduction band of SnO 2 , while the photo-generated holes transfer from the SnO 2 to the valence band of TiO 2 . This phenomenon leads to the accumulation of the photo-generated electrons in the conduction band of TiO 2 , accumulation of the photo-generated holes in the valence band of SnO 2 . In short, the graded heterostructure has more favorable effects to enhance the photocatalytic activity than that of the abrupt heterostructure. The internal electric field at the TiO 2 /SnO 2 interface acts as a selector for photo-generated carriers, which may lead to higher photocatalytic quantum efficiency and carrier concentration under the same external conditions. These intrinsic photocatalytic mechanisms and the interpretation of the interfacial microscopic properties of heterostructure can be used as a basis for the design of the sensing devices and composite photocatalysts with heterostructures. [ABSTRACT FROM AUTHOR]

Largehead hairtail, Trichiurus lepturus, fishery status in the East China Sea was estimated using length frequencies data sets for 2001, 2004, 2009 and 2013 and catch and effort data from 2000~2012. Length frequency data for 8,350 individuals were collected using pair trawl nets. The predominant size classes in the catch comprised of 130-374 mm in 2001, 83-360 mm in 2004, 53-355 mm in 2009, and 23-389 mm in 2013. Growth parameters of asymptotic length ranged from 515.6 to 768.6 mm in 2004 and 2009, growth coefficients ranged from 0.230 to 0.685, and t0 from -0.654 to -0.494. The rate of total mortality (Z) ranged from 0.82 to 2.73 year-1 in 2013 and 2001, respectively. The exploitation rate was estimated to range from 0.660-0.797 year-1. Catch per unit effort estimates showed a consistent decline in catches. This study is a start to bridge the gap between data and information, allowing resource managers to determine management priorities for this economically and ecologically important species in the ECS. [ABSTRACT FROM AUTHOR]

Trichiurus japonicus is an economically valuable species in the East China Sea, whose allowable capture size varies with fishing effort in different years. To clarify the optimum capture size for T. japonicus in the East China Sea, we collected samples and data from T. japonicus targeting fishing gears such as trawls, canvas spreader stow nets and longlines from 2016 to 2020. We estimated growth and mortality parameters using the FiSAT II software, and calculated the size limit standards for capture. The results showed that the inflection point of anal length, the critical anal length and the anal length of one-year-old T. japonicus was 382.84, 397.12, and 216.05 mm, respectively. The anal length of maturity was 230.38 mm, and the minimum capture size (anal length) was 219.23 mm. Based on the yield per recruitment analysis using Beverton-Holt model, the current fishery reference points were under overfishing condition ( t c =0.38 a, F =2.11), and the suggested optimum capture size was 364.64 mm. There would be a sharp decline of T. japonicus catches in the East China Sea if the suggested minimum capture size was substantially higher, which might be non-practical for local fishermen. Therefore, we suggested 220 mm as the capture size limit, which was close to the anal length of one-year-old fish and the anal length of maturity.

In order to understand the growth dynamics of Larimichthys polyactis in spring and autumn along the coast of Zhejiang Province, we used the survey data of bottom trawlers in spring (April) and autumn (November) from 2014 to 2019 along the coast of Zhejiang Province to examine the heterogeneity of L. polyactis growth by constructing a generalized linear model (GLM) and nine linear mixed effect models (LMEM). The results showed that body length of L. polyactis ranged from 15 mm to 210 mm, with an average of 124.12 mm. The dominant body length group ranged from 110 mm to 140 mm. The body weight ranged from 0.04 g to 156.2 g, with an average of 33.28 g. The dominant body weight group ranged from 30 to 50 g. According to the AIC minimum criterion, the LMEM model with the random effects of seasons and water zones on growth parameters a and b was the best. The results of cross validation also showed that the prediction of this model was the best. In the optimal model, the fixed value of growth parameter a was 0.61×10 -4 , which ranged in (0.32-1.91)×10 -4 after adding season and water random effect. The fixed value of parameter b was 2.73, and ranged from 2.49 to 2.86 after adding the random effects of season and water area, indicating that small yellow croaker was under negative allometric growth. Season and water zone had significant effects on the relationship between body length and body weight of small yellow croaker. From a seasonal perspective, the growth rate of small yellow croaker in spring was higher than that in autumn. From water zone perspective, the closer the offshore distance, the faster the growth rate of small yellow croaker.

We investigated population structure, resource density changes of Larimichthys polyactis and its relationship with environmental factors in spring, based on the survey data of bottom trawl in adjacent sea areas of Zhoushan fishery spawning ground protection area from 2014 to 2019. The results showed that the relationship between body length and body weight of Larimichthys polyactis was W =0.44×10 -4 × L 2.78 , and parameter b was less than 3, which indicated that L. polyactis had negative allometric growth in recent years. There was a negative correlation between fullness and body length, with body becoming slender. From 2014 to 2019, body length and weight of L. polyactis were the highest in 2014 and the lowest in 2019. Since 2014, population size of L. polyactis in Zhoushan fishery spawning ground protection area and adjacent sea area had gradually decreased, indicating that the miniaturization of L. polyactis had not altered in recent years. From the perspective of the annual change of resource density, resource density of L. polyactis was higher than that before the establishment of the reserve, indicating that the management and protection of the reserve area played a protective role in the recovery of L. polyactis resources. The fitting results of GAM model showed that water depth and bottom water temperature were the environmental factors closely related to the density distribution of L. polyactis resources. With increasing water depth, the resources showed a fluctuating upward trend and were the highest near the water depth of 60 m. In the range of 12-16 ℃ water temperature, the resources increased with the increases of bottom water temperature. When water temperature was above 16 ℃, resources decreased with the increases of bottom water temperature.

To elucidate the characteristics of fishery resources structure in the Dachenyang Spaw-ning Ground Reserve, the index of relative importance (IRI), biodiversity index and canonical correspondence analysis (CCA) were used to explore the relationship between crustaceans community and marine environment based on the bottom trawl survey data collected from April and November in 2018. A total of 38 crustaceans species were recorded, belonged to 25 genera in 14 families. The dominant species were Oratosquilla oratoria , Portunus trituberculatus , Charybdis bimaculata , and Parapenaeopsis hardwickii . The resource density of crustaceans was generally high in depths below 50 m in spring and in depths above 50 m in autumn. The density in the southern area was higher than nouthern area. The Margalef species richness index ( D ), Shannon diversity index ( H ) and Pielou evenness index ( J ) of crustaceans in spring was higher than that in autumn. The H of crustaceans in depths above 50 m was the highest. Based on cluster analysis and non-matrix multidimentional scaling analysis, the crustaceans could be classified into three groups in spring and four groups in autumn. The differences in crustacean community structure in spring were more significant than in autumn. The results of canonical correspondence analysis (CCA) showed that water depth, bottom temperature, salinity and dissolved oxygen were the main environmental factors affecting species composition and spatial structure of crustaceans in the surveyed area.

To understand the status and dynamics of macrozoobenthos community in Sanmen Bay, we collected benthos samples by Agassiz trawl in November 2015, and February, May and August in 2016. The results showed that: 1) A total of 119 macrozoobenthos species were recorded, with main groups of fishes, crustaceans and molluscs, accounting for 79% of the total number of species. 2) The dominant species of macrozoobenthos throughout the year were Leptochela gracilis , Hyperacanthomysis longirostris and Amblychaeturichthys hexanema . The identity of dominant species changed significantly in different seasons. 3) The annual average biomass and density were 0.025 g·m -2 and 0.07 ind·m -2 , respectively. 4) The Shannon's diversity index of macrozoobenthos in Sanmen Bay varied from 2.21 to 3.18, the Margalef's species richness index varied from 3.25 to 3.78, and the Pielou's evenness index varied from 0.53 to 0.79. Results from abundance-biomass curve analysis showed that the community was moderately disturbed in spring and winter, and slightly disturbed in summer and autumn. Results from Canonical correspondence analysis showed that water depth, temperature, salinity, and pH were the most important environmental factors affecting macrozoobenthos community.

The relative importance index (IRI), mean crowding, niche breadth, and niche overlap (Q ik ) of major fish species were calculated based on two fishery resource surveys from April to May 2016 (spring) in the coastal waters of central and southern Zhejiang Province. The results showed that there were 24 major fish species (IRI:100), the niche breadth values of which differed greatly and were positively correlated with IRI. The niche overlaps of fishes were extremely low in spring. The total amount of species pairs with niche overlap 0.6 (Q ik :0.6) were six in April and five in May, which represented 3.9% and 4.8% of the total pairs, respectively. Results from the redundancy analysis showed that the distribution of major fish species were mainly affected by temperature, salinity, water depth, and dissolved oxygen, which caused ecological differentiation of fish species.

The highly-pathogenic EV71 strain is the primary cause of mortality in hand-foot-and-mouth disease (HFMD) associated with neurological symptoms, for which no clinically effective drugs or vaccines exist. This study aimed to construct infectious cDNA clones of the EV71 highly-pathogenic strain and the cell-culture adapted strain using a reverse genetics approach. The genomic RNAs of EV71 parent strains were used as the templates for RT-PCR amplification, and then the PCR products that overlapped the full-length genome were connected into the pBR322 vector to produce infectious clones of pEV71 (HP) and pEV71 (CCA), respectively. The results showed that the HP strain propagated much more quickly than the CCA strain. The rescued viruses derived from the infectious clones not only maintained their consistency with their parent strains in terms of genomic sequences, but also retained their respective biological phenotypes. This research will contribute to our understanding of EV71 pathogenesis and the development of novel vaccines against HFMD.