Novel cross‑switch seven‑level inverter with triple boost capability and self‑balancing

Jianxin Zhao,Yuanrui Chen,Jun Zeng,Lintao Wang,Junfeng Liu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.9

A novel single-phase seven-level inverter using a cross-switch cell (CSC) is presented in this paper. Compared with conventional inverters, the proposed topology can generate seven-level output, triple boost gain with one dc source and a reduced number of switches. The CSC provides different charging paths for the capacitors to realize self-balance. Hence, the proposed inverter can realize self-balancing without additional control methods or sensors. Moreover, the proposed structure inherently generates negative output voltage levels without a back-end H-bridge circuit, which reduces the voltage stress on switches. This paper has fully illustrated the operation principles, and presents capacitance calculation and loss analysis. Afterward, a comparative study against recently proposed seven-level inverters is introduced, illustrating the merits of the proposed topology in terms of reduced switches, high voltage-boosting capacity, and self-balancing. Ultimately, a laboratory prototype is built for the validation of the proposed inverter.

An Efficient Markerless Deletion System Suitable for the Industrial Strains of Streptomyces

( Jianxin Dong ),( Jiaxiu Wei ),( Han Li ),( Shiyao Zhao ),( Wenjun Guan ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.12

The genus Streptomyces is intensively studied due to its excellent ability to produce secondary metabolites with diverse bioactivities. In particular, adequate precursors of secondary metabolites as well as sophisticated post modification systems make some high-yield industrial strains of Streptomyces the promising chassis for the heterologous production of natural products. However, lack of efficient genetic tools for the manipulation of industrial strains, especially the episomal vector independent tools suitable for large DNA fragment deletion, makes it difficult to remold the metabolic pathways and streamline the genomes in these strains. In this respect, we developed an efficient deletion system independent of the episomal vector for large DNA fragment deletion. Based on this system, four large segments of DNA, ranging in length from 10 kb to 200 kb, were knocked out successfully from three industrial Streptomyces strains without any marker left. Notably, compared to the classical deletion system used in Streptomyces, this deletion system takes about 25% less time in our cases. This work provides a very effective tool for further genetic engineering of the industrial Streptomyces.

Identification of floral aromatic volatile compounds in 29 cultivars from four groups of Osmanthus fragrans by gas chromatography–mass spectrometry

Jianxin Fu,Dan Hou,Yiguang Wang,Chao Zhang,Zhiyi Bao,Hongbo Zhao,Shaoqing Hu 한국원예학회 2019 Horticulture, Environment, and Biotechnology Vol.60 No.4

Osmanthus fragrans Lour. is a popular aromatic ornamental plant and its fl owers are used to enhance the color and fragrance of food. In this study, we analyzed the volatiles of 29 cultivars from all four groups of O. fragrans using a solid-phase microextraction (SPME) technique and gas chromatography–mass spectrometry (GC–MS). We identifi ed 41 volatile organic components that were distributed over fi ve diff erent compound classes, with the majority of the volatile components being dominated by alcohols, ketones, and terpenes, which accounted for 56.6–95.06% of the total volatiles in all tested materials except ‘Zao Yingui’. In ‘Zao Yingui’, alcohols, ketones, and terpenes accounted for only 48.19% of the total volatiles. The diversity of the volatile compounds and their relative contents varied among the four groups and cultivars within each group. The major volatile compounds were α-ionone, β-ionone, 2H-β-ionone, linalool, trans -linalool oxide, cis -linalool oxide, epoxy linalool, geraniol ( Z )-ocimene, and γ-decalactone in all tested cultivars, while nerol and ( Z )-3-hexenyl butanoic acid ester were abundant in several cultivars. The 29 cultivars were classifi ed into fi ve clusters in a hierarchical cluster analysis based on their fl oral volatile compounds. The cultivars of diff erent sexes (male vs. hermaphrodite) had no signifi cant diff erences in the relative contents of the major volatile compounds. This study provides valuable information for understanding the chemical composition of the volatile compounds of O. fragrans fl owers as well as a theoretical basis for the origin, development, and application of modern cultivars of O. fragrans.

Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement <i>via</i> Charge Separation

Hou, Wenpeng,Zhao, Ning-Jiu,Meng, Dongli,Tang, Jing,Zeng, Yi,Wu, Yu,Weng, Yangziwan,Cheng, Chungui,Xu, Xiulai,Li, Yi,Zhang, Jian-Ping,Huang, Yong,Bielawski, Christopher W.,Geng, Jianxin American Chemical Society 2016 ACS NANO Vol.10 No.5

<P>The installation of heterojunctions on the surfaces of carbon nanotubes (CNTs) is an effective method for promoting the charge separation processes needed for CNT-based electronics and optoelectronics applications. Conjugated polymers are proven state-of-the-art candidates for modifying the surfaces of CNTs. However, all previous attempts to incorporate conjugated polymers to CNTs resulted in unordered interfaces. Herein we show that well-defined chains of regioregular poly(3-hexylthiophene) (P3HT) were successfully grown from the surfaces of multiwalled CNTs (MWNTs) using surface-initiated Kumada catalyst-transfer polycondensation. The polymerization was found to proceed in a controlled manner as chains of tunable lengths were prepared through variation of the initial monomer-to-initiator ratio. Moreover, it was determined that large-diameter MWNTs afforded highly ordered P3HT aggregates, which exhibited a markedly bathochromically shifted optical absorption due to a high grafting density induced planarization of the polymer chains. Using ultrafast spectroscopy, the heterojunctions formed between the MWNTs and P3HT were shown to effectively overcome the binding energy of excitons, leading to photoinduced electron transfer from P3HT to MWNTs. Finally, when used as prototype devices, the individual MWNT-g-P3HT core-shell structures exhibited excellent photoresponses under a low illumination density.</P>

Stronger plasticity of leaf characteristics is associated with better shade adaptation in Calycanthaceae

Chao Zhang,Jianxin Fu,Bin Dong,Lihua Zhou,Hongbo Zhao 한국원예학회 2020 Horticulture, Environment, and Biotechnology Vol.61 No.6

To understand how Calycanthaceae species adapt to diff erent light levels, we examined the responses of leaf structure, chlorophyll(Chl) content, and Chl fl uorescence of fi ve Calycanthaceae species to diff erent light conditions. With the reductionof light irradiance, total leaf thickness of Sinocalycanthus chinensis signifi cantly decreased, and that of Chimonanthus nitenswas generally the same. The other three species, Ch. praecox , Ch. salicifolius , and Calycanthus fl oridus var. glaucus , showedmoderate plasticity of leaf structure. With shade treatments, the Chl a content in the leaves of Ch. nitens increased, whilethat in Ch. salicifolius decreased. However, the Chl a content in Ch. praecox , Ca. fl oridus var. glaucus , and S. chinensis wasnot changed with decreased light levels. Leaves of four species (except Ch. salicifolius ) showed higher Chl b content andtotal Chl content, and leaves of all fi ve species showed a lower Chl a / b ratio in shade. The maximal quantum effi ciency ofphotosystem II (PSII) (F v /F m ) and the eff ective quantum yield of PSII (Φ PSII ) in S. chinensis were the same regardless of thelight regime, but those of the other four species were signifi cantly lower in full sunlight. Another Chl fl uorescence parameter,non-photochemical Chl fl uorescence quenching, was signifi cantly higher in full sunlight. Our results revealed that among thefi ve Calycanthaceae species, S. chinensis exhibited the highest plasticity of leaf structure in response to diff erent irradiancesand Ch. nitens was considered to have the highest shade tolerance.

Post-meiotic Deficient Anther1 (PDA1) Encodes an ABC Transporter Required for the Development of Anther Cuticle and Pollen Exine in Rice

Lu Zhu,Jianxin Shi,Guochao Zhao,Dabing Zhang,Wanqi Liang 한국식물학회 2013 Journal of Plant Biology Vol.56 No.1

The tapetum of the anther locule encloses the malereproductive cells and plays a supportive role for normalpollen development. However, the underlying mechanismremains less understood. Previously, we identified a completerecessive male sterile mutant, post-meiotic deficient anther1(pda1), with abnormal postmeiotic tapetal development. Inthis study we comprehensively characterized pda1. Chemicalanalysis uncovered that pda1 anther had significant lowerlevels of cutin monomers and cuticular waxes. PDA1 geneencodes an ATP-binding cassette (ABC) half-transporter,namely OsABCG15, which is conserved from algae tohigher plants. In situ RNA hybridization assay showed thatPDA1 is strongly expressed in tapetal cells, and weakly inmicrospores during the anther development. Additionally,the expression of two pollen exine biosynthetic genesCYP704B2 and CYP703A3 was dramatically reduced inpda1 mutant anthers. Altogether, these observations suggestthat the tapetum-expressed ABC transporter PDA1 plays acrucial role in secreting lipidic precursors from the tapetumto developing microspores and the anther epidermis.

A Lectin Receptor Kinase Positively Regulates ABA Response During Seed Germination and Is Involved in Salt and Osmotic Stress Response

Keqin Deng,Qiming Wang,Jianxin Zeng,Xinhong Guo,Xiaoying Zhao,Dongying Tang,Xuanming Liu 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6

Lectin receptor-like kinases (LecRK) are widespread in higher plants; however, little is known about their physiological roles. In this study, At1g70130 (designated LecRK-b2), an Arabidopsis LecRK gene, has been investigated. LecRK-b2 was predominantly expressed during seed germination, and its expression was ceased following germination. The expression of LecRK-b2 was induced by abscisic acid (ABA), salt, and osmotic stress. LecRK-b2 lossof- function mutation slightly reduced the ABA sensitivity during seed germination, and this reduced sensitivity was demonstrated not due to lower ABA accumulation level in the seeds. Dual-luciferase transient expression assay confirmed that the transcription factor ABSCISIC ACID INSENSITIVE3 (ABI3) could activate the luciferase under driving of LecRK-b2 promoter. LecRK-b2 transcription level was found to be down-regulated in abi3 during seed germination. Furthermore, LecRK-b2 loss-of-function mutation reduced the salt and osmotic sensitivity during early development stage of Arabidopsis. Taken together, these results suggest that LecRK-b2 functions as a positive regulator of the ABA response during the seed germination and is involved in salt and osmotic stress response in the early development stage.

Error Accumulation and Transfer Effects of the Retrieved Aerosol Backscattering Coefficient Caused by Lidar Ratios

Houtong Liu,Zhenzhu Wang,Jianxin Zhao,Jianjun Ma 한국광학회 2018 Current Optics and Photonics Vol.2 No.2

The errors in retrieved aerosol backscattering coefficients due to different lidar ratios are analyzed quantitatively in this paper. The actual calculation shows that the inversion error of the aerosol backscattering coefficients using the Fernald backward-integration method increases with increasing inversion distance. The greater the error in the lidar ratio, the faster the error in the aerosol backscattering coefficient increases. For the same error in lidar ratio, the smaller actual aerosol backscattering coefficient will get the larger relative error of the retrieved aerosol backscattering coefficient. The errors in the lidar ratios for dust or the cirrus layer have great impact on the retrievals of backscattering coefficients. The interval between the retrieved height and the reference range is one of the important factors for the derived error in the aerosol backscattering coefficient, which is revealed quantitatively for the first time in this paper. The conclusions of this article can provide a basis for error estimation in retrieved backscattering coefficients of background aerosols, dust and cirrus layer. The errors in the lidar ratio of an aerosol layer influence the retrievals of backscattering coefficients for the aerosol layer below it.

Sea buckthorn (Hippophae rhamnoides L.) oil enhances proliferation, adipocytes differentiation and insulin sensitivity in 3T3-L1 cells

Ting Zhang,Xuze Qin,Yuxin Cao,Jianxin Zhang,Jun-Xing Zhao 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.11

The objective of this study is to investigate theeffects of sea buckthorn oil (SBO) on proliferation, adipogenicdifferentiation and insulin sensitivity of 3T3-L1cells. Results showed that SBO increased cell proliferationability, accompanied by up-regulated proliferating cellnuclear antigen content (p\0.05) and p38 activity(p\0.05). SBO also promoted adipogenesis and enhancedadipogenic transcriptional factors expression. Mitochondrialbiogenesis related gene expressions were elevated inSBO treated cells (p\0.05). Of note, SBO also increasedglucose uptake and glucose transporter 4 abundance(p\0.05). Cells treated with SBO exhibited greaterphosphorylated insulin receptor substrate 1 (p\0.05),phosphorylated-Akt (p\0.05) and phosphorylated AMPactivatedprotein kinase (p\0.01) contents. When takentogether, these results suggest that SBO promotes 3T3-L1cells proliferation, adipogenesis and insulin sensitivity.

A Defect in Zinc Finger Protein Double B-box 1a (DBB1a) Causes Abnormal Floral Development in Arabidopsis

Qiming Wang,Xiaoju Tu,Keqin Deng,Jianxin Zeng,Xiaoying Zhao,Dongying Tang,Xuanming Liu 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6

The double B-box (DBB) type zinc finger protein has thus far been shown to be involved in photomorphegenesis in Arabidopsis thaliana. Here, we show that DBB1a is expressed in the embryo, cytolden, and flower. Misexpression of DBB1a in mutant plants resulted in abnormal numbers and patterns of floral organs. We further show that DBB1a could regulate expression of several floral homeotic genes, including APETALA 2, APETALA 3, PISTILLATA, and AGAMOUS. Interestingly, expression of the microRNA gene MiR172, which is involved in organ boundary establishment, was also misregulated in the dbb1a mutant plants. Our study identified a previously uncharacterized role of DDB1a in regulation of expression of floral homeotic genes and miR172, which is important for understanding of floral pattern formation.