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Background:: Angular contact ball bearings are the most popular bearing type used in the high speed spindle for machining centers, The performance of the bearing directly affects the machining efficiency of the machine tool, Obtaining a higher value is the direction of its research and development. Objective:: By analyzing the research achievements and patents of electric spindle angular contact bearings, summarizing the development trend provides a reference for the development of electric spindle bearings. Methods:: Through the analysis of the relevant technology of the electric spindle angular contact ball bearing, the advantages and disadvantages of the angular contact ball bearing are introduced, and the research results are combined with the patent analysis. Results:: With the rapid development of high-speed cutting and numerical control technology and the needs of practical applications, the spindle requires higher and higher speeds for bearings. In order to meet the requirements of use, it is necessary to improve the bearing performance by optimizing the structure size and improving the lubrication conditions. Meanwhile, reasonable processing and assembly methods will also have a beneficial effect on bearing performance. Conclusion:: With the continuous deepening of bearing technology research and the use of new structures and ceramic materials has made the bearing's limit speed repeatedly reach new highs. The future development trend of high-speed bearings for electric spindles is environmental protection, intelligence, high speed, high precision and long life.

Background: The trachea is an important part of the respiratory system. Long-term airway diseases and the effects of human physiological conditions can cause trachea stenosis. This will seriously affect patients’ physical health. Tracheal stents can provide durable support by means of dilating the narrowed area; they can effectively relieve the patient's breathing difficulties, which is of value that is more practical. Objective: To meet the vital requirements for better adaptation to the human airway environment and prevent complications associated with stent placement, the construction and materials of tracheal stents have been improved constantly. Methods: This paper investigates various representative patents related to the tracheal stent. The structure type, placement method and applications situation of these tracheal stents are discussed. Results: The characteristics of different types of tracheal stents are analyzed. This paper analyzes the main problems in its development. The solutions to the issues and the current and future research on tracheal stents are discussed. Conclusion: The tracheal stents are classified into metal stent, silicone stent, biodegradable stent and hybrid material stent. Further improvements are needed in the aspects of structural design, safety, applicability, biocompatibility, algorithm of drive model of tracheal stent. More related patents about tracheal stents need to be developed.

Background: With a growing demand for blueberries, the planting area of blueberries is also increasing. However, the main method of picking blueberries is the traditional manual picking, so the operation of picking is the most time-consuming and laborious in the chain of production. Objective: By analyzing and discussing the patents of equipment of blueberry picking, some valuable conclusions have been drawn to predict the future research and development of equipment of blueberry picking. Methods: This paper sketches out various current representative patents relevant to equipment of blueberry picking. Results: Through summarizing a large number of patents about equipment of blueberry picking, the characters of those patents are analyzed and compared, and further development tendency of equipment of blueberry picking is discussed. Conclusion: The research on the multifunction, intelligence, versatility of blueberry picking machine is helpful in solving the problems of low efficiency, low quality and poor versatility.

Background: Bearing testing machine is the key equipment for bearing design, theoretical research and improvement, and it plays an important role in the performance of bearing life, fatigue, vibration and working temperature. With the requirements of aerospace, military equipment, automobile manufacturing and other industrial fields of the bearing are becoming higher and higher. There is an urgent need for high-precision and high-efficiency bearing testing machines to monitor and analyze the performance of bearings. Objective: By analyzing the recent patents, the characteristics and existing problems of the current bearing testing machine are summarized to provide references for the development of bearing test equipment in the future. Methods: This paper reviews various representative patents related to the third generation bearing testing machines. Results: Although the structure of bearing testing machines is different, the main problems in the structure and design principle of bearing testing machine have been summarized and analyzed, and the development of trend and direction of the future bearing testing machine have been discussed. Conclusion: Bearing testing machines for health monitoring of bearing life cycle is of great significance. The current bearing testing machine has basically achieved the monitoring and analysis However, due to the emergence of new types of bearings, further improvement is still needed. With the development of testing technology towards intelligent and big data-driven direction, bearing testing machine is moving towards the type of cloud computing and large-scale testing.

Background: One of the critical factors affecting the life of bearings is the bearing temperature during operation, so the temperature is an important parameter to detect the running state of the bearing. The abnormal increase in bearing temperature can reflect problems such as bearing damage, lack of lubricating oil, and installation errors. With the continuous improvement of rotating machinery equipment operating speed, load level and equipment processing accuracy requirements, there is an urgent need to detect and analyze the temperature rise of bearings. Objective: By analyzing recent representative patents for bearing temperature detection, we summarize the characteristics and problems of current bearing temperature detection devices and provide a reference for the future development of bearing temperature detection devices Methods: This article traces the recent representative patents related to bearing temperature detection method and device structure. Results: Through the investigation of a large number of patents of bearing temperature detection devices, the main existing problems in the system and structure of bearing temperature detection are concluded and analyzed, and the development of bearing temperature detection is discussed in the future. Conclusion: The bearing temperature measuring device is significant for analyzing bearing heating and detecting the running state of the bearing. The current research results need further development and improvement. With the development of automated detection technology, bearing temperature measurement is also evolving towards intelligence and dynamics. It is foreseeable that more related patents on bearing temperature detection will be invented.

DNA methylation plays an important role in reproduction. Tibetan pigs maintain high sperm motility, even under extreme conditions at high altitudes. However, the DNA methylation mechanisms underlying testicular plateau adaptations in Tibetan pigs remain unclear. We determined the genomic DNA methylation level in the testicular tissues of Tibetan pigs living at high altitudes (TP) and of Yorkshire pigs that migrated to high altitudes (YP) using the fluorescence method. Quantitative real-time PCR and western blots were used to measure the gene and protein expression levels, respectively, of three DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B) and hypoxia-inducible factor 2α (HIF2α). We found that the genomic DNA methylation level and the mRNA and protein expression levels of the four genes were all significantly lower in the testicular tissues of TP than YP. In short, compared with YP, the downregulation of DNA methyltransferases in the TP testes led to lower levels of genomic DNA methylation, which would facilitate higher sperm motility. Meanwhile, HIF2α expression in the TP testes was down-regulated, which might contributes to TP testes’ adaption to the plateau environment. This study provided new insights into the DNA methylation mechanisms underlying plateau adaptations in TP testicles.