Progress in the Study of Enhanced Heat Exchange in Phase Change Heat Storage Devices.

In comparison with sensible heat storage devices, phase change thermal storage devices have advantages such as high heat storage density, low heat dissipation loss, and good cyclic performance, which have great potential for solving the problem of temporal and spatial imbalances in the transfer and utilization of heat energy. However, there are also issues such as the small thermal conductivity of phase change materials (PCMs) and poor efficiency in heat storage and release, and in recent years, enhanced heat transfer in phase change thermal storage devices has become one of the research hotspots for optimizing thermal storage devices. Although there have been reviews of enhanced heat transfer technology for phase change thermal storage devices in the literature, there is still insufficient research on the summarization of the enhanced heat transfer mechanism, structural optimization, and applications of phase change thermal storage devices. This Review provides a review of enhanced heat transfer in phase change thermal storage devices from two aspects: internal structure enhanced heat transfer and heat exchange medium flow channel enhanced heat transfer. It summarizes the enhanced heat transfer measures of various types of phase change thermal storage devices and discusses the role of structural parameters in enhanced heat transfer. It is hoped that this Review will provide some references for scholars engaged in research on phase change thermal storage heat exchangers.

Timosaponin BII inhibits TGF-ß mediated epithelial-mesenchymal transition through Smad-dependent pathway during pulmonary fibrosis.

Pulmonary fibrosis (PF) is a progressive and fatal interstitial lung disease with limited therapeutic options at present, and epithelial-mesenchymal transition (EMT) is recognized as a major cause of lung fibrosis. Our previous work has confirmed that total extract of Anemarrhena asphodeloides Bunge [Asparagaceae] exerted the effect of anti-PF. As a main constituent of Anemarrhena asphodeloides Bunge [Asparagaceae], the effect of timosaponin BII (TS BII) on drug-induced EMT process in PF animals and alveolar epithelial cells remains unknown. In this study, we evaluated the effect of TS BII on bleomycin (BLM)-induced PF. The results showed that TS BII could restore the structure of lung architecture and MMP-9/TIMP-1 balance in fibrotic rat lung and inhibit collagen deposition. Moreover, we found that TS BII could reverse the abnormal expression of TGF-ß1 and EMT-related marker proteins including E-cadherin, vimentin, and α-SMA. Besides, aberrant TGF-ß1 expression and phosphorylation of Smad2 and Smad3 in BLM-induced animal model and TGF-ß1-induced cell model were downregulated by TS BII treatment, indicating that EMT in fibrosis was suppressed by inhibition of TGF-ß/Smad pathway both in vivo and in vitro. In summary, our study suggested that TS BII could be a promising candidate for PF treatment.

Total extract of Anemarrhenae Rhizoma attenuates bleomycin-induced pulmonary fibrosis in rats.

Pulmonary fibrosis is a progressive interstitial lung disease with poor prognosis. Anemarrhenae Rhizoma is a traditional Chinese herbal medicine and has been applied in clinical practice for a long history. Recently, components of Anemarrhenae Rhizoma were reported to possess anti-inflammatory and immunomodulatory features; however, the effect of them on pulmonary fibrosis remains unknown. In this study, we explored the therapeutic effect of total extract of Anemarrhenae Rhizoma (TEAR) on bleomycin-induced pulmonary fibrosis. Pulmonary fibrosis rat model was established by a single intratracheal instillation of bleomycin, three doses of TEAR were intragastrically administered for consecutive 28 days. Subsequent to sacrificing of rats, pulmonary fibrosis was observed in rats treated with bleomycin, but administration of TEAR attenuated lung fibrosis, as evidenced by the improved lung histopathological damage and decreased weight loss and lung index. Moreover, TEAR treatment inhibited the inflammatory response in lung fibrosis, which was shown by the reduced nitrogen oxide level and myeloperoxidase activity. Furthermore, TEAR modulated the redox balance in lung tissue by alleviated lipid peroxidation and enhanced enzymatic antioxidants activity. Meanwhile, TEAR protected the rats from fibrosis in a dose-dependent manner, and the anti-fibrotic activity of TEAR may be related to the modulation of TGF-ß1/Smad signaling pathway. Collectively, TEAR alleviates bleomycin-induced pulmonary fibrosis, indicating perspectives for development of a potential agent for lung fibrosis therapy.

Numerical simulation of embryo transfer: how the viscosity of transferred medium affects the transport of embryos.

BACKGROUND: Embryo transfer (ET) is a key step of assisted reproductive procedures, where the transferred medium containing the embryos is injected into the uterine cavity through a transcervical catheter and blended with intrauterine fluid in the uterine cavity. This procedure determines the delivery sites of embryos in the uterine cavity and has crucial impact on the implantation. Due to practical restrictions and ethical issues, it is often difficult to perform an in vivo study in humans to examine factors that affect the motions and delivery of embryos during ET. Alternatively, mathematical modeling is a powerful tool to that end. RESULTS: A computational model is developed to simulate the intrauterine mixing flow and track the embryo motions. Two important factors affecting the intrauterine flow are studied via this model: the viscosity of the transferred medium and the injection speed. Numerical results show that the dispersion pattern and the final delivery sites of the embryos are significantly influenced by the viscosity of the transferred medium. Specially, increasing the transferred medium viscosity close to that of the uterine fluid can enhance the probability that the embryos are delivered close to the fundus and keep them from being dragged backward to the cervix during catheter withdrawal. In addition, a slow injection speed can lower the driving force on the embryo during ET, which can prevent the embryo from being injured. CONCLUSIONS: Based on our study, the practice of using a transferred medium with similar viscosity to that of the uterine fluid and a slow injection speed is recommended for real embryo transfer procedures in clinic.