Coupled inductor based zero‑voltage‑switching buck/boost converter

Shanshan Wang,Yihua Hu,Ming Gao,Jianjiang Shi,Tao Liu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.7

This paper proposes a zero-voltage-switching (ZVS) Buck/Boost converter (BBC). In addition, an auxiliary circuit based on a coupled inductor is introduced to realize ZVS for the main MOSFETs. The magnetic coupling inductor plays the role of filtering and provides ZVS conditions for the main MOSFETs. Since all of the switches can achieve soft switching conditions, and the conduction loss of the auxiliary circuit is small, the conversion efficiency for the overall system is improved. When compared with the traditional ZVS implementation methods based on magnetic coupling inductors used in Buck, Boost, and Buck/Boost converters, the proposed topology can prevent current notches on the current waveform of the input source. Since there are no notches on the input source current, when the proposed ZVS implementation method is applied to an interleaved parallel BBC structure, it has a smaller current ripple of the input source. Finally, experimental results are given and analyzed. Based on these results, both the ZVS conditions and efficiency improvement are verified.

Gene expression profiles of skin from cyclin dependent kinases 5-knockdown mice

Yang Shanshan,Jiao Dingxing,Song Tao,Rui Ping,Fan Ruiwen,Ma Zengjun 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.4

Objective: This study aimed to identify genes regulated by cyclin dependent kinases 5 (CDK5) that participate in hair pigmentation in mice. Methods: The mRNA expression profiles of skin samples from CDK5-knockdown mice were constructed using high-throughput RNA sequencing and compared with those of wild-type mice. Results: In total, 8,002 known genes were differentially expressed between CDK5-knockdown and wild-type mice. Of these, 3,658 were upregulated and 4,344 were downregulated in the skin of CDK5-knockdown mice. An additional 318 previously unknown genes were also differentially expressed, with 171 downregulated and 147 upregulated genes in the skin of CDK5-knockdown mice. Of the known genes expressed in mouse skin, 80 were associated with hair color, with 61 showing lower expression and 19 exhibiting higher expression in skin of CDK5-knockdown mice. Importantly, the expression of the tyrosinase-related protein 1 (TYRP1) and the calcium signaling pathway were also found to be regulated by CDK5, suggesting that pigmentation is regulated by CDK5 via the calcium signaling pathway and TYRP1. Conclusion: The transcriptome profiles obtained from the skin of CDK5-knockdown mice compared to wild-type mice provide a valuable resource to help understand the mechanism by which CDK5 regulates melanogenesis in mice and other animals.

Analysis of a coupled inductor boost three‑port converter with high voltage gain for renewable energy systems

Ming Gao,Shanshan Wang,Weichen Yu,Tao Liu,Jianjiang Shi 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.12

A conventional boost three-port converter is combined with a coupled-inductor-based boost-flyback converter in this work to produce a high-step-up three-port converter. The proposed converter inherits the benefits of two conventional converters, including high voltage gain, few elements, and energy recycling of the leakage inductor. In addition, the voltage stresses of switches are considerably lower than the output voltage. Therefore, switches with low ON resistance can be selected to reduce the conduction loss. Additionally, the freewheel diodes are capable of zero-current switching. The operation principle can be divided into three modes of operation, and the three steady-state operation modes are analyzed under each of the three conduction modes. The operation principles of various modes, the voltage characteristics, the boundary of the coupled inductor, and the proposed converter’s control method are discussed in depth to provide detailed theoretical guidance to designers. Then, the simulation and experiment results of a laboratory prototype with an 18 V PV source, 24 V battery pack, and 180 V output are presented to validate the feasibility of the theoretical analysis.

Transparent and Self-Powered Multistage Sensation Matrix for Mechanosensation Application

Zhang, Qian,Jiang, Tao,Ho, Donghae,Qin, Shanshan,Yang, Xixi,Cho, Jeong Ho,Sun, Qijun,Wang, Zhong Lin American Chemical Society 2018 ACS NANO Vol.12 No.1

<P>Electronic skin based on a multimodal sensing array is ready to detect various stimuli in different categories by utilizing highly sensitive materials, sophisticated geometry designs, and integration of multifunctional sensors. However, it is still difficult to distinguish multiple and complex mechanical stimuli in a local position by conventional multimodal E-skin, which is significantly important in the signals’ feedback of robotic fine motions and human–machine interactions. Here, we present a transparent, flexible, and self-powered multistage sensation matrix based on piezoelectric nanogenerators constructed in a crossbar design. Each sensor cell in the matrix comprises a layer of piezoelectric polymer sandwiched between two graphene electrodes. The simple lamination design allows sequential multistage sensation in one sensing cell, including compressive/tensile strain and detaching/releasing area. Further structure engineering on PDMS substrate allows the sensor cell to be highly sensitive to the applied pressures, representing the minimum sensing pressure below 800 Pa. As the basic combinations of compressive/tensile strains or detaching/releasing represent individual output signals, the proposed multistage sensors are capable of decoding to distinguish external complex motions. The proposed self-powering multistage sensation matrix can be used universally as an autonomous invisible sensory system to detect complex motions of the human body in local position, which has promising potential in movement monitoring, human–computer interaction, humanoid robots, and E-skins.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2018/ancac3.2018.12.issue-1/acsnano.7b06126/production/images/medium/nn-2017-06126z_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn7b06126'>ACS Electronic Supporting Info</A></P>

Bridging the top-down and bottom-up approaches to smart urbanization? A reflection on Beijing’s Shuangjing International Sustainable Development Community Pilot

Shuwen Zhou,Haokun Fu,Shanshan Tao,Yanan Han,Mingrui Mao 서울시립대학교 도시과학연구원 2023 도시과학국제저널 Vol.27 No.-

The relation between planning and smart city development is interwoven. On the one hand, planning is being digitalized and ‘smartificated’, but threatened by the growing dominance of IT corporations in urban development. On the other hand, bottom-up smart initiatives at the neighbourhood level are emerging to challenge top-down control, but the relation between top-down and bottom-up approaches is conflicting and often disconnected. In the Chinese context, a newly established neighbourhood planning mechanism – community duty planners (CDPs) – appears to open up opportunities for bridging bottom-up and top-down approaches to smart city development. In Beijing, the CDPs are institutionalized under Beijing’s Refined Urban Management (RUM) framework which aims to improve the city’s built environment and quality of living. The CDPs play the role of intermediary actors connecting local government with the communities. The article is a reflection on the Shuangjing International Sustainable Development Community Pilot and the CDPs of Shuangjing Neighbourhood. It describes and reflects on how planning institutions can influence smart city development at the neighbourhood level and how bottom-up initiatives can be connected to long-term top-down plans.

VDR promotes testosterone synthesis in mouse Leydig cells via regulation of cholesterol side chain cleavage cytochrome P450 (Cyp11a1) expression

Hu Yuanyuan,Wang Ling,Yang Ge,Wang Shanshan,Guo Miaomiao,Lu Hongzhao,Zhang Tao 한국유전학회 2023 Genes & Genomics Vol.45 No.11

Background The vitamin D receptor (VDR) mediates the pleiotropic biological actions that include osteoporosis, immune responses and androgen synthesis.VDR is widely expressed in testis cells such as Leydig cells, Sertoli cells, and sperm. The levels of steroids are critical for sexual development. In the early stage of steroidogenesis, cholesterol is converted to pregnenolone (precursor of most steroid hormones) by cholesterol side-chain lyase (CYP11A1), which eventually synthesizes the male hormone testosterone. Objective This study aims to reveal how VDR regulates CYP11A1 expression and affects testosterone synthesis in murine Leydig cells. Methods The levels of VDR, CYP11A1 were determined by quantitative real-time polymerase chain reaction (RT-qPCR) or western blot. Targeted relationship between VDR and Cyp11a1 was evaluated by dual-luciferase reporter assay. The levels of testosterone concentrations in cell culture media serum by enzyme-linked immunosorbent assay (ELISA). Results Phylogenetic and motif analysis showed that the Cyp11a1 family had sequence loss, which may have special biological functions during evolution. The results of promoter prediction showed that vitamin D response element (VDRE) existed in the upstream promoter region of murine Cyp11a1. Dual-luciferase assay confirmed that VDR could bind candidate VDREs in upstream region of Cyp11a1, and enhance gene expression. Tissue distribution and localizatio analysis showed that Cyp11a1 was mainly expressed in testis, and dominantly existed in murine Leydig cells. Furthermore, over-expression VDR and CYP11A1 significantly increased testosterone synthesis in mice Leydig cells. Conclusions Active vitamin D3 (VD3) and Vdr interference treatment showed that VD3/VDR had a positive regulatory effect on Cyp11a1 expression and testosterone secretion. VDR promotes testosterone synthesis in male mice by up-regulating Cyp11a1 expression, which played an important role for male reproduction.

VDR mediated HSD3B1 to regulate lipid metabolism and promoted testosterone synthesis in mouse Leydig cells

Xue Zhen,Zhuang Jianan,Bai Hao,Wang Ling,Lu Hongzhao,Wang Shanshan,Zeng Wenxian,Zhang Tao 한국유전학회 2022 Genes & Genomics Vol.44 No.5

Background: The vitamin D receptor (VDR) mediates the pleiotropic biological actions that include osteoporosis, immune responses and androgen synthesis wherein the VDR transcriptionally regulates expression of the genes involved in this complex process. 3β-Hydroxysteroid dehydrogenase-1 (HSD3B1) is an absolutely necessary enzyme for androgen synthesis. Objective: The purpose of the present study was to explore the molecular mechanism of VDR mediated HSD3B1 regulation of lipid metabolism and testosterone synthesis. Methods: The levels of VDR, HSD3B1 and lipid metabolism associated protein were determined by quantitative real-time polymerase chain reaction (RT-qPCR) or western blot. The levels of testosterone concentrations in cell culture media serum by enzyme-linked immunosorbent assay (ELISA). Targeted relationship between VDR and Hsd3b1 was evaluated by dual-luciferase reporter assay. Results: Based on the data analysis of mouse testicular proteome, we found that the expression of HSD3B1 was significantly reduced after VDR deletion. Here, we identified that Hsd3b1 was widely expressed in different tissues of mice by RT-qPCR, and was highly expressed in testis, and mainly located in testicular Leydig cells. Dual-luciferase assay confirmed that VDR could bind candidate vitamin D responsive elements (VDREs) in upstream region of Hsd3b1, and enhance gene expression. Furthermore, over-expression VDR and HSD3B1 significantly increased testosterone synthesis in mice Leydig cells. Meanwhile, Lpl expression was significantly down-regulated and Angptl4 expression was significantly up-regulated in the present of HSD3B1 overexpression. Both LPL and ANGPTL4 play important roles in regulating lipid metabolism. Conclusions: The present study unveiled VDR mediated HSD3B1 to regulate lipid metabolism and promoted testosterone synthesis in mouse Leydig cells. These findings will greatly help us to understand the roles of VDR and HSD3B1 in testosterone synthesis and lipid metabolism.