Search

The Laval nozzle is an important part of the supersonic separator, which structure determines the separation efficiency of supersonic separator. In order to study the flow and condensation process in Laval nozzle with different convergent section, convergent section is designed by Bicubic parametric curve, Quintic polynomial curve, Witoszynski curve and Translation of Witoszynski curve, respectively. The numerical model for the supersonic condensing flow process of CH4-CO2 mixture gas is established and the User Define Function is invoked for numerical simulation. The effects of different linetypes of convergent section on the flow and condensation parameters in nozzle were investigated. The results confirm the Laval nozzle designed by Translation of Witoszynski curve has strengths such as the most stable pressure change, the best refrigeration effect, the most intense spontaneous condensation, and the nucleation rate is 1.610×1022m−3s−1, the number of droplets is as high as 2.023×1015m−3 at the nozzle outlet far better than the other nozzles. Therefore, Translation of Witoszynski curve is recommended to design the convergent section of Laval nozzle in supersonic separator.

To date, although a promising anti-inflammatory activity of oligomeric proanthocyanidins (OPCs) has been observed in asthma, the mechanism responsible for these immunomodulatory properties remains obscure. Dendritic cells (DCs) that reside in the airway have been widely perceived as an important contributor to asthma. Our study was to demonstrate OPCs' effects on maturation and immunoregulation of pulmonary CD11c+ dendritic cells (DCs). BALB/c mice were exposed to ovalbumin (OVA) to induce murine model of asthma. In addition, pulmonary DCs and bone marrow-derived DCs (BMDCs) cultures were used to evaluate impacts of OPCs on DCs function. The results obtained here indicated that OPCs treatment dramatically reduced airway inflammation, such as the infiltration of inflammatory cells and the levels of allergen-specific serum IgE and Th2 cytokines. The expression of co-stimulatory molecules especially CD86 distributed on pulmonary DCs and bone marrow-derived DCs (BMDCs) also markedly declined. The phosphorylation of cAMP responsive element-binding protein (CREB) was significantly inhibited while no changes were observed in the expression of cAMP responsive element modulator (CREM). By transferring BMDCs into the airways of naive mice, we found that OPCs-treated DCs (DC+OVA+OPC) were much less potent in promoting CD4+ T cells proliferation than OVA-pulsed DCs (DC+OVA), followed by the ameliorated eosinophilic inflammation in airway. Our findings tailor a novel profile of OPCs in the regulation of DCs function, shedding new light on the therapeutic potential of OPCs in asthma management.

Olfactory ensheathing cell (OEC) transplantation is one promising technology for the treatment of spinal cord injury. Many studies have been focusing on the functional improvement after OEC implantation in spinal cord injury of animals. However, little is known about the mechanisms about how OECs respond to the proapoptotic microenvironment after transplantation. We use the hypoxia and serum deprivation (HSD) paradigm in OECs to evaluate the effects of the ischemic damage. OECs underwent caspase-dependent apoptosis during HSD and a pan-caspase inhibitor specifically blocked the cell death. In addition, HSD resulted in a time-dependent decrease of mitochondrial membrane potential DeltaPsi(m), triggering a transient increase in p53 content and activated p53 in a time-dependent manner. In summary, our data suggest that HSD trigger apoptotic OECs death, which may be related to mitochondria dysfunction and the dependence of p53.

Olfactory ensheathing cells (OECs) transplantation is a promising or potential therapy for spinal cord injury (SCI). However, their clinical use is limited because of the availability. Adipose-derived stem cells (ADSCs) have been identified as an alternative source of adult stem cells in recent years. ADSCs could be differentiated into various mesenchymal tissues cells such as chondrocytes, adipocytes, osteoblasts, and myocytes and also could be differentiated into neural lineages. In this study, we examined the feasibility of using ADSCs as a source of stem cells for the differentiation of OECs by co-culture approach. When co-cultured with OECs, the ADSCs on three-dimensional collagen scaffolds were differentiated into OEC-like cells, with similar morphology and antigenic phenotypes (p75NTR+/Nestin+/GFAP-) of OECs. Co-cultured ADSCs were positive for several important functional markers of mature OECs such as neurotrophic factor GDNF, BDNF and myelin protein PLP and the conditioned medium of OEC-like cells could significantly promote DRG neuron growth and axon sprouting without NGF supporting in contrast to that of the ADSCs. Our results showed that ADSCs had the potential to differentiate into OEC-like cells on the three-dimensional collagen scaffolds in vitro.

Considerable research has been focused on the development of bone morphogenetic protein-2 (BMP-2) delivery system for homologous and efficient bone regeneration. The aim of the present study was to develop a collagen-based targeting bone repair system. A collagen-binding domain (CBD) was added to the N-terminal of native BMP-2 to allow it bind to collagen specifically. We showed that the collagen-binding bone morphogenetic protein-2 (named bone morphogenetic protein2-h, BMP2-h) had maintained the full biological activity as compared to rhBMP2 lacking the CBD. In vitro functional study also demonstrated that collagen matrix could maintain higher bioactivity of BMP2-h than native BMP-2. When demineralized bone matrix (DBM) impregnated with BMP2-h was implanted subcutaneously in rats, homogeneous bone formation was observed. Moreover, in a rabbit mandible defect model, surgical implantation of collagen matrix loaded with BMP2-h exhibited remarkable osteoinductive properties and excellent homogeneous bone formation. Our studies suggested that this novel collagen-based BMP-2 targeting bone repair system induced better bone formation not only in quantity but also in quality. Similar approaches may also be used for the repair of other tissue injuries.