The Cellular Structure and Mechanical Properties of Polypropylene/Nano-CaCO3/Ethylene-propylene-diene-monomer Composites Prepared by an In-Mold-Decoration/Microcellular-Injection-Molding Process.

Polypropylene (PP)-composite foams were prepared by a combination process of microcellular injection molding (MIM) and in-mold decoration (IMD). The effect of ethylene propylene diene monomer (EPDM) on the crystallization properties, rheological properties, microstructure, and mechanical properties of PP-composite foams was studied. The effect of the additives on the strength and toughness of PP-composite foam as determined by the multiscale simulation method is discussed. The results showed that an appropriate amount of EPDM was beneficial to the cell growth and toughening of the PP blends. When the content of EPDM was 15 wt%, the PP-composite foams obtained the minimum cellular size, the maximum cellular density, and the best impact toughness. At the same time, the mesoscopic simulation shows that the stress concentration is the smallest, which indicates that 15 wt% EPDM has the best toughening effect in these composite materials.

The Cellular Structure and Toughness of Hydrogenated Styrene-Butadiene Block Copolymer Reinforced Polypropylene Foams.

Polypropylene nanocomposites containing varying amounts of Styrene-ethylene-butadiene-styrene block copolymer (SEBS) were prepared through the supercritical nitrogen microcellular injection-molding process. Maleic anhydride (MAH)-grafted polypropylene (PP-g-MAH) copolymers were used as compatibilizers. The influence of SEBS content on the cell structure and toughness of the SEBS/PP composites was investigated. Upon the addition of SEBS, the differential scanning calorimeter tests revealed that the grain size of the composites decreased, and their toughness increased. The results of the rheological behavior tests showed that the melt viscosity of the composite increased, playing a role in enhancing the cell structure. With the addition of 20 wt% SEBS, the cell diameter decreased from 157 to 66.7 µm, leading to an improvement in the mechanical properties. Compared to pure PP material, the impact toughness of the composites rose by 410% with 20 wt% of SEBS. Microstructure images of the impact section displayed evident plastic deformation, effectively absorbing energy and improving the material's toughness. Furthermore, the composites exhibited a significant increase in toughness in the tensile test, with the foamed material's elongation at break being 960% higher than that of pure PP foamed material when the SEBS content was 20%.

Inhibition of Lactobacillus fermentum SHY10 on the white membrane production of soaked pickled radish.

The formation of white bio-membrane (shenghua) on the surface of pickle leads to uneatable and spoiled products, which has been the key problem restricting the development of Sichuan pickle industry. In this study, the 17 microorganisms in the white membrane of pickled radish were screened and identified, of which Candida parapsilosis was the main strain causing "shenghua". The membrane-forming ability of Candida parapsilosis was determined by crystal violet staining to explore its adaptability to the fermentation environment concerning temperature and oxygen. It was found that Candida parapsilosis had the strongest membrane-forming capacity under the aerobic condition at 37°C, with the highest OD595 nm value reached to 3.473 ± 0.07 at 72 h post inoculation. This research identified Lactobacillus fermentum SHY10 to be the inhibitor of the membrane production of Candida parapsilosis via the Oxford cup method on a Petri dish, and via co-inoculation with Candida parapsilosis in pickles. Furthermore, this study specified that the cell-free supernatant (CFS) of L. fermentum SHY10 had the most significant inhibitory effects and likely to result from protein substances in the CFS. Proteases treated CFS had significantly reduced inhibitory effects against membrane formation, which confirmed that the active component was protein substances. Overall, this study identified a functional LAB strain with significant inhibitory effects against the white membrane formation in pickles, which provide a safe and consumer-friendly solution for the membrane problem in the fermented vegetable industry.

Effects of modified atmosphere packaging on the postharvest quality of mulberry leaf vegetable.

Fresh mulberry leaf vegetable is nutritive and becoming popular. However, available preservation technologies are deficient. In present work, the effects of two kinds of modified atmosphere packaging on postharvest quality of fresh mulberry leaf vegetable stored at 4 °C were evaluated. The respiration rate of samples in the modified polyethylene packages (MP20) was 12.88-22.65% lower than that in normal polyethylene packaging (CK). The content of total soluble solids, soluble protein, and total polyphenol in MP20 was less changed than that in CK, and the vitamin C retention was higher as well. Moreover, the lignin content in MP20 was lower than that in CK during storage (19.79% vs 13.38% at day 8), and that was significantly positively related to the polyphenol oxidase and peroxidase activities inhibition. Taken together, a packaging with moderate gas permeability (MP20) is suitable for nutrition maintenance and lignification inhibition of fresh mulberry leaf vegetable during cold storage.

Microbial composition and correlation between microbiota and quality-related physiochemical characteristics in chongqing radish paocai.

Chongqing radish paocai (paocai) is produced by fermentation of fresh vegetables. It gained attention for its non-negligible contribution in Sichuan cuisine and potential health benefits. This study explored microbial structures in six home-made paocai using high through-put sequencing. Key microbial communities were identified based on significant correlations with quality-related physiochemical attributes. Results suggest bacterial diversity level significantly decreased during fermentation, while fungal diversity level were inconsistent across different alpha-diversity indexes. Firmicutes and Proteobacteria were the predominant bacterial phylum in all samples. Lactic acid bacteria, namely Lactobacillus and L. plantarum were the predominant bacteria at genus and species levels. Fungi had overall weak correlations with physiochemical attributes, several bacterial species significantly correlated with physiochemical attributes, including Lactobacillus plantarum, Lactobacillus acetotolerans, and Weissella cibaria. Overall, this study identified key microbial communities and discussed their functional roles that could contribute to consistent production of high-quality Chongqing radish paocai.

Volatile composition analysis of tree peony (Paeonia section Moutan DC.) seed oil and the effect of oxidation during storage.

Peony (Paeonia section Moutan DC.) seed oil is a novel vegetable oil with unique aromatic profile. The objectives of this study were to characterize the volatile compounds with optimized analysis conditions, and to study the effects of oxidation during storage. The Headspace Solid-phase Micro-extraction (HS-SPME) conditions were optimized with factors including extraction fiber, extraction time and temperature, as well as sample amount and desorption time. Then, the aromatic compounds extracted from peony seed oil were determined using the odor activity value (OAV) method coupled with the GC-olfactometry. Results found that the best HS-SPME conditions were DVB/CAR/PDMS fibers with magnetic stirring for 50 min of extraction at 60°C. The optimal sample amount was 4 g with 6 min of desorption. Forty-one volatile components were found, and 19 aromatic components were identified using GC-MS and GC-olfactometry. This is the first study to describe 4,7-dimethylbenzofuran in peony seed oil with a unique aroma of grass, light bitter, and fragrance. The stability of alcohol and terpenoids decreased as accelerated oxidation progresses. This study provides the theoretical basis for the sensory attributes, and shelf-life of peony seeds oil products for industry production and marketing.

Ternary composite films with simultaneously enhanced strength and ductility: Effects of sodium alginate-gelatin weight ratio and graphene oxide content.

This study aimed to simultaneously enhance the strength and ductility of films by adding graphene oxide (GO) into the sodium alginate (SA)-gelatin film system to prepare SA-gelatin-GO ternary composite films. The effects of the SA/gelatin weight ratio and the GO content on the morphology, structural, mechanical, hydrophobic, water vapor barrier, hygroscopic, and optical properties of composite films were investigated. Results showed that tensile strength and elongation at break values of the composite film with 0.5% GO content were significantly improved from 37.00 to 48.01 MPa and 20.19% to 25.75%, respectively, compared with the SA-gelatin film without GO, suggesting GO with the content of 0.5% simultaneously enhance the strength and ductility of the SA-gelatin film, which was due to the interaction of hydrogen bonds and the good dispersibility of GO in the film matrix. The surface hydrophobicity of composite films increased first and then decreased with increasing GO content. In addition, the hygroscopicity of composite films reduced due to the GO addition, especially when the GO content was 0.25%. The SA-gelatin-GO ternary composite films provide a good select for food packaging materials, especially the materials that require high strength and fine ductility.

High Thermal Conductivity and Anisotropy Values of Aligned Graphite Flakes/Copper Foil Composites.

Much attention has been paid to graphite flakes/copper (GFs/Cu) composites for thermal management due to their remarkable thermal properties. Most studies focus on the interface interaction between GFs and Cu in composites. However, controlling the orientation of GFs still remains a challenge. Herein, we report a reliable method to ensure consistent orientation of GFs in the composites. Firstly, the disorder GFs were well arranged on the surface of copper foil by tape casting process in the casting machine. Then highly aligned GFs/Cu composites were fabricated by hot pressing process in a vacuum hot-pressing furnace, with the volume fraction of graphite from 30% to 70%. The SEM images show that the obtained GFs/Cu composites presented a layer-by-layer structure or network structure with a different content of GFs. The thermal conductivity of GFs/Cu composites exhibited an extreme anisotropy due to the highly aligned GFs. The ultrahigh thermal conductivity of GFs/Cu composites with 70 vol% GFs reached 741 W/(m·K), while through-plane thermal conductivity was just 42 W/(m·K). The alignment of GFs and interfacial thermal resistance were deeply analyzed and a thermal conductivity model for GFs/Cu composites was established. Our work provides a new idea to significantly enhance the thermal transportation performance of GFs/Cu composites by well controlled alignment of GFs in Cu matrix.

The Adverse Effects of Se Toxicity on Inflammatory and Immune Responses in Chicken Spleens.

Selenium (Se) is an essential trace element, but excessive intake of Se could induce Se poisoning, and result in various health problems. NF-κB regulated many molecules of the immune response and the inflammatory response, and Th1/Th2 balance played a key in the regulation of immune response. The aim of this study is to investigate the role of NF-κB pathway and Th1/Th2 imbalance in the adverse influence of Se poisoning on chicken spleens. In the current study, 90 chickens were randomly divided into two groups (n = 45 per group). The chickens were maintained either on a basal diet (the control group) containing 0.2 mg/kg Se or a high supplemented diet (the Se group) containing 15 mg/kg Se for 45 days. Then, we observed the pathohistology of spleen cells and detected NO content, iNOS activity, and the expression of NF-κB, iNOS, COX-2, PTGE, IL-6, TNF-α, Foxp3, IL-4, and IFN-γ in chicken spleens. In chicken spleens of the Se group, the result showed typical characteristics of inflammation: the content of NO and the activity of iNOS were increased, and the expression of NF-κB, iNOS, COX-2, PTGE, IL-6, TNF-α, and IL-4 was enhanced and that of Foxp3 and IFN-γ was decreased. Our study showed that Se toxicity could promote inflammation via NF-κB pathway, impairing the immune function, and changing Th1/Th2 balance in the chicken spleens.

Mitochondrial DNA diversity of Monopterus albus from the Sichuan Basin of China.

Genetic diversity of Monopterus albus in a wild population in the Sichuan Basin was investigated by employing mtDNA polymorphisms. The mitochondrial control region was sequenced for a total of 59 individuals collected from four localities. These sequences (553 bp) belonged to 13 haplotypes defined by eight polymorphic sites. The haplotypes were clustered into one lineage, suggesting that Monopterus albus from the Sichuan Basin might originate from a single ancestor in maternal lineages. The genetic differentiation between the population from Zhongxian in Chongqing city and the other three populations, from Mianyang, Longchang, and Ya'an in Sichuan province (F (ST): 0.29167-0.55126), was higher than that among the latter three (F (ST): -0.04196 to 0.05984). Little genetic differentiation was found in the three populations from Sichuan province (Nm: -6.21 to 3.93), and the Zhongxian population also showed lower genetic heterogeneity (P (i): 0.00077 +/- 0.00027; H (d): 0.404 +/- 0.130). The combination of limited variation and weak phylogenetic structure revealed that the Monopterus albus from the Sichuan Basin exhibited lower mtDNA diversity and should probably be treated as a monogroup genetically.