Downey Kline (grainqueen96)

Poly(butylene adipate-co-terephthalate) (PBAT), a compostable polymer, filled with different weight percentage of unbleached nano chitin (NC; 10%, 30% and 50%), a biodegradable filler from crustacean waste, were prepared from the extruded blends by injection moulding and 3D printing. The nanochitin required was prepared from chitin isolated from prawn shells (Fenneropenaeus indicus). The nanochitin crystals were observed to contain carboxylic acid surface functional groups as assessed by FT-IR, 13C solid state NMR (SS NMR) spectroscopy, zeta potential measurements and the extent of the same was estimated by potentiometric titration. The PBAT-NC nanocomposites were characterized SS NMR spectroscopy, FT-IR spectroscopy, wide angle X-ray diffraction, dynamic mechanical analysis, DSC and TGA. Thermal and mechanical properties of the nanocomposites were determined. The moulded nanocomposites changed more and more rigid with increasing weight percentage of NC without significant change in the tensile strength. The TGA indicated that the thermal stability of PBAT could be improved but not significantly by the addition of NC. Wound healing was enhanced in the presence of the nanocomposite while in vivo toxicity was significant at high concentration. The PBAT-NC nanocomposites could be moulded in to useful articles such as laptop charger cover, rat cover for washing machine, planters and key holders under conditions similar to that used in the processing of LDPE.Wound healing is a complex, dynamic and difficult process. Much effort and attempt has been made to accelerate this process. The purpose of this study is to prepare nanoparticles loaded with vaccarin (VAC-NPS)hydrogel and evaluate its effect on promoting wound healing. In the present study, the physicochemical properties of VAC-NPS were characterized. Transmission electron microscopy (TEM) was used to observe the morphology of VAC-NPS. Human umbilical vein endothelial cells (HUVEC) was employed to assessment the biocompatibility of VAC-NPS in vitro. The wound healing function of VAC-NPS hydrogels was evaluated in the full-thickness dermal wound in a rat model. The results indicated that VAC-NPS was spherical like particles with uniform particle size distribution and no obvious aggregation with a diameter of (216.6 ± 10.1)nm. The loading capacity and encapsulation efficiency of VAC in the nanoparticles were (14.3 ± 1.2) % and (51.7 ± 1.7) % respectively. MTT assay demonstrated that the VAC-NPS had no cytotoxicity and could promote HUVEC proliferation and migration. In vivo results showed that VAC-NPS promotes wound healing, and the mechanism may be through up-regulating IL-1β and PDGF-BB, promoting angiogenesis. VAC-NPS might have a potential application value for the treatment of the wound healing and a promising performance in bio-medically relevant systems.Our previous study has revealed that Pseudomonas plecoglossicida JUIM01 produced 2-keto-d-gluconic acid (2KGA) and re-utilized 2KGA as an alternative carbon source to support cell growth after complete consumption of glucose. Phosphorylation of intracellular 2KGA to 2-keto-6-phosphogluconic acid by 2-ketogluconate kinase (KguK) was regarded as the first step of 2KGA catabolism in Pseudomonas cytoplasm. In the present study, a kguK gene encoding 2-ketogluconate kinase from P. plecoglossicida JUIM01 was cloned and heterologously expressed in Pichia pastoris. The recombinant KguK showed the highest activity at 30-33 °C and pH 7.7, and high stability at 33 °C. Under the optimal conditions of 30 °C and pH 7.7 with addition of 5 mM Mg2+, the purified and concentrated (~30 folds) KguK had a specific activity of 3649.6 U/g and a Michaelis constant for 2KGA of 8.7 × 10-4 M. Knockout of kguK could retard but not completely inhibit 2KGA catabolism, indicating other existing 2KGA utilization pathway(s). The kguK-knockout P. plecoglossicida significantly reduced 2KGA re-utilization without negative effects on cell growth, glucose cons