Exergoeconomic analysis and optimization of wind power hybrid energy storage system.

The hybrid energy storage system of wind power involves the deep coupling of heterogeneous energy such as electricity and heat. Exergy as a dual physical quantity that takes into account both 'quantity' and 'quality, plays an important guiding role in the unification of heterogeneous energy. In this paper, the operation characteristics of the system are related to the energy quality, and the operation strategy of the wind power hybrid energy storage system is proposed based on the exergoeconomics. First, the mathematical model of wind power hybrid energy storage system is established based on exergoeconomics. Then, wind power experiments of three forms of thermal-electric hybrid energy storage are carried out, and RSM is used to analyze the power quality and exergoeconomic characteristics of the system, and the optimal working conditions of the experiment are obtained. Finally, an optimization strategy is proposed by combining experiment and simulation. The system efficiency, unit exergy cost and current harmonic distortion rate are multi-objective optimization functions. The three algorithms evaluate the optimal solution based on standard deviation. The results show that the exergoeconomics can effectively judge the production-storage-use characteristics of the new system of ' wind power + energy storage'. The thermal-electric hybrid energy storage system can absorb the internal exergy loss of the battery, increase the exergy efficiency by 10%, reduce the unit exergy cost by 0.03 yuan/KJ, and reduce the current harmonic distortion rate by 8%. It provides guidance for improving the power quality of wind power system, improving the exergy efficiency of thermal-electric hybrid energy storage wind power system and reducing the unit cost.

Time-responsive osteogenic niche of stem cells: A sequentially triggered, dual-peptide loaded, alginate hybrid system for promoting cell activity and osteo-differentiation.

The efficacy of stem cell-based bone tissue engineering has been hampered by cell death and limited fate control. A smart cell culture system with the capability of sequentially delivering multiple factors in specific growth stages, like the mechanism of the natural extracellular matrix modulating tissue formation, is attractive for enhancing cell activity and controlling cell fate. Here, a bone forming peptide-1 (BFP-1)-laden mesoporous silica nanoparticles (pep@MSNs) incorporated adhesion peptide, containing the arginine-glycine-aspartic acid (RGD) domain, modified alginate hydrogel (RA) system (pep@MSNs-RA) was developed to promote the activity and stimulate osteo-differentiation of human mesenchymal stem cells (hMSCs) in sequence. The survivability and proliferation of hMSCs were enhanced in the adhesion peptide modified hydrogel. Next, BFP-1 released from pep@MSNs induced hMSCs osteo-differentiation after the proliferation stage. Moreover, BFP-1 near the cells was self-captured by the additional cell-peptide cross-linked networks formed by the ligands (RGD) binding to receptors on the cell surface, leading to long-term sustained osteo-stimulation of hMSCs. The results suggest that independent and sequential stimulation in proliferation and osteo-differentiation stages could synergistically enhance the survivability, expansion, and osteogenesis of hMSCs, as compared to stimulating alone or simultaneously. Overall, this study provided a new and valid strategy for stem cell expansion and osteo-differentiation in 2D or 3D culture systems, possessing potential applications in 3D bio-printing and tissue regeneration.

Peptide-laden mesoporous silica nanoparticles with promoted bioactivity and osteo-differentiation ability for bone tissue engineering.

Combination of mesoporous silica materials and bioactive factors is a promising niche-mimetic solution as a hybrid bone substitution for bone tissue engineering. In this work, we have synthesized biocompatible silica-based nanoparticles with abundant mesoporous structure, and incorporated bone-forming peptide (BFP) derived from bone morphogenetic protein-7 (BMP-7) into the mesoporous silica nanoparticles (MSNs) to obtain a slow-release system for osteogenic factor delivery. The chemical characterization demonstrates that the small osteogenic peptide is encapsulated in the mesoporous successfully, and the nitrogen adsorption-desorption isotherms suggest that the peptide encapsulation has no influence on mesoporous structure of MSNs. In the cell experiment, the peptide-laden MSNs (p-MSNs) show higher MG-63 cell proliferation, spreading and alkaline phosphatase (ALP) activity than the bare MSNs, indicating good in vitro cytocompatibility. Simultaneously, the osteogenesis-related proteins expression and calcium mineral deposition disclose enhanced osteo-differentiation of human mesenchymal stem cells (hMSCs) under the stimulation of the p-MSNs, confirming that BFP released from MSNs could significantly promote the osteogenic differentiation of hMSCs, especially at 500µg/mL of p-MSNs concentration. The peptide-modified MSNs with better bioactivity and osteogenic differentiation make it a potential candidate as bioactive material for bone repairing, bone regeneration, and bio-implant coating applications.

Detection of periodontal pathogens in the patients with aortic aneurysm.

BACKGROUND: The occurrence and development of aortic aneurysm (AA) are associated with infection. Some researchers have detected the DNA of periodontal pathogens in AA samples in certain populations. However, it has not been done in Chinese population. The objective of this study was to evaluate the prevalence of periodontal pathogens in oral tissue samples and aneurysm samples of AA patients. METHODS: Eighty-nine subjects with AA and 59 subjects without AA were examined. Periodontal clinical parameters were evaluated. Unstimulated saliva and subgingival plaque samples were collected from all subjects. Twenty-six dissected AA samples were obtained. Evidence of eight periodontal pathogens including Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Prevotella intermedia (Pi), Tannerella forsythensis (Tf), Treponema denticola (Td), Campylobacter rectus (Cr), Fusobacterium nucleatum (Fn), and Prevotella nigrescens (Pn) was ascertained in all samples by 16S rRNA-based polymerase chain reaction (PCR) assay. RESULTS: The periodontal indexes including plaque index (PLI), probing depth (PD), bleeding index (BI), and clinical attachment loss (CAL), of the six Ramfjord index teeth were significantly higher in the AA group than those in the control group (P < 0.01). Eight periodontal pathogens in subgingival plaque samples were more frequently detected in the AA group than in control group. The difference in prevalence between the groups was significant for six (out of eight) periodontal pathogens assayed (Pg, Pi, Fn, Pn, Tf, and Td, P < 0.01). Additionally, all eight periodontal pathogens were more frequently detected in saliva samples of the AA group than in those of the control group, again with six (out of eight) (Pg, Pi, Fn, Cr, Tf, and Td) displaying significant differences in prevalence between the two groups (P < 0.01). Out of 26 aneurysm samples examined, Pg, Pi, Fn, Cr and Tf were detected in 6 (23.1%), 2 (7.7%), 3 (11.5%), 1 (3.8%), 2 (7.7%), respectively, and Aa, Pn, and Td were not detected in dissected aneurysm samples. CONCLUSION: Results of this study suggested that periodontal infection is associated with the occurrence of AA.

Rapidly-deposited polydopamine coating via high temperature and vigorous stirring: formation, characterization and biofunctional evaluation.

Polydopamine (PDA) coating provides a promising approach for immobilization of biomolecules onto almost all kinds of solid substrates. However, the deposition kinetics of PDA coating as a function of temperature and reaction method is not well elucidated. Since dopamine self-polymerization usually takes a long time, therefore, rapid-formation of PDA film becomes imperative for surface modification of biomaterials and medical devices. In the present study, a practical method for preparation of rapidly-deposited PDA coating was developed using a uniquely designed device, and the kinetics of dopamine self-polymerization was investigated by QCM sensor system. It was found that high temperature and vigorous stirring could dramatically speed up the formation of PDA film on QCM chip surface. Surface characterization, BSA binding study, cell viability assay and antibacterial test demonstrates that the polydopamine coating after polymerization for 30 min by our approach exhibits similar properties to those of 24 h counterpart. The method has a great potential for rapid-deposition of polydopamine films to modify biomaterial surfaces.