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Cryopreservation of embryos is important for long-distance embryo transfer and conservation of genetic resources. Porcine research is important for animal husbandry and biomedical research. However, porcine embryos are difficult to cryopreserve because of their high cytoplasmic lipid content and sensitivity to chilling stress. Vitrification is more efficient than slow freezing, and vitrification is mostly used in embryo cryopreservation. So far, the vitrification process of porcine embryos has been continuously improved, resulting in improved survival rates of warmed embryos and farrowing rates after the transplant procedure. It is worth noting that automatic vitrification has made great progress, which is expected to promote the standardization and application of vitrification. In this article, the vitrification process of porcine embryos at the blastula stage and early development stages is reviewed in detail. In addition, the efficiency of different vitrification systems was compared. In addition, we summarize technology that can improve the survival rate of cryopreserved porcine embryos, such as delipidation methods (including physical delipidation and chemical delipidation) and medium improvements (including chemically defined media and adding antioxidants). Meanwhile, gene expression changes during cryopreservation are also elaborated.

Exploring the effect and mechanism of farmland transfer on agricultural green total factor productivity (AGTFP) in China is of great significance for exerting the effectiveness of China’s farmland transfer policy and promoting green agricultural development. Based on panel data from 30 provinces from 2005 to 2020, this paper applies a two-way fixed effects model to analyze the impact of farmland transfer on AGTFP, and the mechanism of farmland transfer on AGTFP is also investigated. We find that farmland transfer has a significant and sound promoting effect on AGTFP, with respect to multiple robustness checks; there is heterogeneity regarding the impact of farmland transfer on AGTFP in terms of food functions, and farmland transfer can promote regional AGTFP through nonagricultural labor transfer and agricultural technology utilization. When considering the fact that farmland transfer has increased China’s AGTFP, the Chinese government should continue to adhere to the farmland transfer policy, accelerate nonagricultural labor transfer, improve the level of agricultural technology utilization, and ultimately promote green agricultural development.

BACKGROUND Mosaicplasty osteochondral transplantation (MOT) has been proved a feasible choice for the treatment of talus osteochondral injury. It can reduce ankle pain and allow performance of daily living activities and elementary sports. However, there are very little data on the restoration of normal life with large lesions. Our investigation focused on assessing outcomes in patients with large lesions. MATERIAL AND METHODS The MOT operation was used, and the donor site was located at the lateral condyle of the femur. Clinical evaluation included the Berndt and Harty outcome question, Visual Analog Scale (VAS) pain score (during rest, walking and running), American Orthopedic Foot and ankle Association (AOFAS) score, International Knee Documentation Committee (IKDC) subjective knee evaluation form, and the Short Form 36 (SF-36). Twenty-four months after surgery, the graft binding was assessed by MRI using the magnetic resonance observation of cartilage repair tissue (MOCART) score. RESULTS We assessed 26 patients, including 14 males and 12 females. The average follow-up time was 33.9±5.2 months. The average lesion size was 173.1±23.5 mm². The average VAS score during rest improved from 4.62±0.85 preoperatively to 1.08±0.27 postoperatively (P

Background: Fluid shear stress affects cell viability and cell differentiation. This study aimed to build a bioreactor for tissue engineering in which the cultured cells are exposed to custom designed multilevel laminar shear stress. Methods: The bioreactor was built based on a multi-layer plate configuration and equipped with an online monitoring system. The diameters of the diversion holes of each layer varied from 0.8mm to 1.4mm. Computational fluid dynamics and tracer liquid imaging velocity measurement were used to study the fluid field distribution. Finally, human umbilical cord mesenchymal stem cells (hUCMSCs) were cultivated in this bioreactor system. Results: The actual flow field distribution was consistent with the simulation results, and the average relative error of the flow velocity was 10.52%. The variation in shear stress of each layer was less than 3.0e-5 Pa, indicating that the flow microenvironment was uniform in each layer. Additionally, the shear stress increased with increasing diameters of the diversion holes. Cell culture experiments of Vero cells and hUCMSCs showed that the system continuously monitored morphological characteristics of the cells. The designed bioreactor achieved the desired proliferation, indicating that the bioreactor provided a suitable microenvironment for cell growth. Conclusion: The fluid shear stress within the bioreactor can be specified as required, and the morphological characteristics of the cells can be monitored in real time. It achieved the proliferation of hUCMSCs. This bioreactor system will facilitate the study of tissue engineering.

This paper focuses on an aerodynamic noise study of outlet elbow of Continuous Positive Airway Pressure (CPAP) machine by analyzing the wall pressure fluctuations and predicting the far filed sound generated by turbulent flow. A hybrid approach combing the Larger-Eddy Simulation (LES) and Ffcowcs Williams-Hawkings (FW-H) acoustic analogy was used to simulate the flow distribution as well as calculate the flow-induced noise for a three-dimensional elbow pipe. Then, a different elbow structure was designed to form the appropriate structure for the air outlet via considering the sound pressure level of each model. As a result, elbow with guiding plate was demonstrated to be an effective method to reduce the aerodynamic noise strength since this design could weaken the wall pressure fluctuation and vortex magnitude. Furthermore, the decreased magnitude could reach more than 1dB when velocity increased from 5m/s to 9m/s. The results of simulation were a little higher than experimental results since the background noise, elbow vibration and the defect of FW-H equation which couldn’t be eliminated thoroughly. Key words: Exhaust elbow, aerodynamic noise, Large-Eddy simulation, guiding plate, FW-H Acoustic Analogy

Joint diseases like osteoarthritis usually are accompanied with inflammatory processes, in which pro-inflammatory cytokines mediate the generation of intracellular reactive oxygen species (ROS) and compromise survival of subchondral osteoblasts. Melatonin is capable of manipulating bone formation and osteogenic differentiation of mesenchymal stem cells (MSCs). The aim of this work was to investigate the anti-inflammatory effect of melatonin on MSC proliferation and osteogenic differentiation in the absence or presence of interleukin-1 beta (IL-1β), which was used to induce inflammation. Our data showed that melatonin improved cell viability and reduced ROS generation in MSCs in a dose-dependent manner. When exposed to 10 ng/mL IL-1β, various concentrations of melatonin resulted in significant reduction of ROS by 34.9% averagely. Luzindole as a melatonin receptor antagonist reversed the anti-oxidant effect of melatonin in MSCs with co-exposure to IL-1β. Real-time RT-PCR data suggested that melatonin treatment up-regulated the expression of CuZnSOD and MnSOD, while down-regulated the expression of Bax. To investigate the effect of melatonin on osteogenesis, MSCs were cultured in osteogenic differentiation medium supplemented with IL-1β, melatonin, or luzindole. After exposed to IL-1β for 21 days, 1 μm melatonin treatment significantly increased the levels of type I collagen, ALP, and osteocalcin, and 100 μm melatonin treatment yielded the highest level of osteopontin. Our study demonstrated that melatonin maintained MSC survival and promoted osteogenic differentiation in inflammatory environment induced by IL-1β, suggesting melatonin treatment could be a promising method for bone regenerative engineering in future studies.

This paper presents an optimized controller to achieve better synchrony in human-ventilator interactions. An experimental platform was built by using data acquisition, a set of signal collectors, and a blower wired with driver circuit. The related signals were all acquired and processed by a program written with the optimized controller in LabVIEW. Then, the comparative experiments were conducted in this paper. Specifically, in the experiments, the conventional PID controller led to the obvious pressure spike which was 2cmH2O higher than inspiratory pressure, whereas the proposed controller can decrease the pressure quickly without the pressure spike when switching to the expiration state. Also, the Pressure-Volume Loop indicated that the area from the optimized controller was smaller than the conventional PID controller. These results showed a good performance from the proposed controller in terms of synchrony, and this optimized controller will be useful for the future ventilation. Index Terms - PID controller, optimized controller, pressure spike.