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Polyethylene (PE) has found widespread use as a packaging material. Plastics waste disposal, as one of the serious environmental issues, has caused much criticism. The environmental oxidative- and bio- dual degradable linear low-density polyethylene (LLDPE) samples containing Eco-Benign Plastics (EBP) pro-oxidant additives were submitted to an investigation aimed at evaluating their preliminary oxidative degradation in natural environment or accelerated oven aging and their ultimate biodegradation in solid incubation substrate or soil composting conditions. Original and test samples submitted to abiotic oxidation including photo degradation and thermal degradation were characterized by means of FT-IR and GPC. Biodegradation test simulating soil burial and composting conditions reveals that the biodegradation degree exceeded 30%. The degradation process is accompanied by a dramatic change in the structural characteristics of the test samples. It is clear that LLDPE-EBP formulations are effective in promoting the oxidation and subsequent biodegradation of polyethylene in natural and soil environment.

Influenza virus-like particles (VLPs) are effective vaccines against influenza infection, which can be produced either in insect cells by recombinant baculovirus (BV) infection or in mammalian cells by DNA plasmid transfection. However, VLPs produced from baculovirus/insect cells are difficult to purify due to baculovirus contamination; VLPs produced by plasmid transfection are limited by scale-up capability. In this study, a BacMam BV, in which three CMV-promoters drive the hemagglutinin, neuraminidase, and matrix of influenza virus was constructed. This baculovirus can deliver these genes into mammalian cells/hosts and subsequently influenza VLPs can be produced and secreted from transduced cells. Transduction conditions were optimized and influenza VLPs were purified from transduced 293T cells. Mice were vaccinated with BV transduction-produced VLPs, plasmid transfection-produced VLPs, and BacMam BV. Two vaccinations of each vaccine induced high hemagglutination-inhibition (HAI) titers and prevented influenza virus infection. In contrast, following a single vaccination, all mice vaccinated with each vaccine had significantly lower lung viral titers compared to unvaccinated mice. Remarkably, mice vaccinated with a single dose of BV transduction-produced VLPs survived challenge, whereas mice vaccinated with one dose of BacMam BV- or plasmid transfection-produced VLPs had 60-80% survival. This finding is particularly significant for producing easily purified VLPs. The BacMam system is an alternative strategy for VLP production, which is easy to scale up and purify. Besides, BacMam BV can be used as a gene delivery vector to produce VLPs in vivo, to stimulate immune responses.

Combined with the research on the route plan of the peacetime military logistics distribution home and abroad, this paper proposes a method to connect genetic algorithm with fuzzy c-means clustering, which firstly clusters the army users with fuzzy math language into several classes according to the distance between the users and the military logistics distribution center, then plans the route with dual objective functions that are time and expense ones by genetic algorithm. Through a case analysis with the method, it proves that the method can decrease the time in a large scale but increase the expense in quite a small scale improving the military effectiveness, which indicates that the method is right and feasible and will provide a new thought for future studies on the problem.

The tensile strain capacity of concrete under uniaxial tension is investigated using the direct tension test method. The adopted method of testing improves the weak bond strength between the embedded bar and concrete and reduces the stress concentration at the end of the embedded bar. The method has overcome the difficulties in centralizing and aligning the two embedded bars in the specimens. Seven mixes of concrete were designed to study the effects of age, compressive strength and mineral admixture on the tensile strain capacity. The investigation shows that the tensile strain capacity of concrete is a relatively independent parameter. The average tensile strains at failure and at 90% failure load are 120 and 100 μe, respectively. The corresponding characteristic tensile strain values at failure and at 90% failure load are 86 and 78 μe, respectively.

The establishment of in vitro model will provide optimal conditions for the study of human papillomavirus (HPV)-associated cervical cancer. In this study, E6 and E7 gens of HPV31 were cloned and expressed in E. coli. The recombinant proteins were purified and used as antigens to immunize mice for the production of polyclonal antibody. Mammalian expression plasmid pBudCE4. 1-HPV31-E6/E7 was also constructed and transfected into C33A cells. The transfected cells were then selected by Zeocin. The expressions of the E6 and E7 mRNAs and proteins were detected by RT-PCR and Western blot respectively. A stable cervical cancer cell line was established as an in vitro model for the study of human papillomavirus type 31(HPV31) associated cervical cancer.

PBD-1 is an antibacterial peptide that plays an important role in defence system of porcine. To produce PBD-1 with bioactivity in Pichia pastoris, according to published amino acid sequence of porcine beta-defensin 1(PBD-1) and the partiality codon of yeast, the PBD-1 gene was synthesized by PCR and cloned into pPIC9K to construct the recombinant expression vector pPIC9K-PBD-1, the obtained recombinant plasmid was linearized by Sal I, and then transformed into SMD1168 by electroporation. Under the control of the promoter AOX1, an approximately 4.5 kD PBD-1 peptide was expressed. Antibacterial activity assay shows that the PBD-1 has the antibacterial activity on Staphylococcus aureus. This is the first secreted expression of porcine beta-defensin 1 gene in Pichia pastoris.