Projection value‑based smooth adaptive control strategy of single‑phase DC‑AC converters

Wenxun Xiao,Huiting Huang,Jiankun Mao,Fan Xie,Bo Zhang,Yanfeng Chen,Dongyuan Qiu 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.4

State-space modeling is often used to design power converters so that the performance of the closed-loop control system can meet design requirements. However, single-phase DC-AC converters based on constant state feedback control have some issues, including long response times and unpredictable robustness. To solve these problems, a novel control strategy based on state feedback control (SFC), called the smooth projection adaptive strategy (SPAS), is developed by adaptively changing the state feedback coefficient according to the projection value of the system. First, a state space model of the DC-AC converter with the adaptive state feedback control law is established. Then based on the SPAS and considering parameters perturbation, two control laws named current-mode control (CMC) and voltage-mode control (VMC) are proposed, and their robustness are further discussed. Furthermore, the design method of the proposed control system in the digital control framework is presented. Finally, experiments on a 400 W prototype, and comparative analyses among the proposed control laws and the conventional PI control method are carried out. The results show that the proposed CMC has apparent superiority in terms of both static and dynamic performance.

Biodegradable charged polyester-based vectors (BCPVs) as an efficient non-viral transfection nanoagent for gene knockdown of the BCR-ABL hybrid oncogene in a human chronic myeloid leukemia cell line

Yang, Chengbin,Panwar, Nishtha,Wang, Yucheng,Zhang, Butian,Liu, Maixian,Toh, Huiting,Yoon, Ho Sup,Tjin, Swee Chuan,Chong, Peter Han Joo,Law, Wing-Cheung,Chen, Chih-Kuang,Yong, Ken-Tye The Royal Society of Chemistry 2016 Nanoscale Vol.8 No.17

<P>First-line therapy of chronic myelogenous leukemia (CML) has always involved the use of BCR-ABL tyrosine-kinase inhibitors which is associated with an abnormal chromosome called Philadelphia chromosome. Although the overall survival rate has been improved by the current therapeutic regime, the presence of resistance has resulted in limited efficacy. In this study, an RNA interference (RNAi)-based therapeutic regime is proposed with the aim to knockdown the BCR-ABL hybrid oncogene using small interfering RNA (siRNA). The siRNA transfection rates have usually been limited due to the declining contact probability among polyplexes and the non-adherent nature of leukemic cells. Our work aims at addressing this limitation by using a biodegradable charged polyester-based vector (BCPV) as a nano-carrier for the delivery of BCR-ABL-specific siRNA to the suspension culture of a K562 CML cell line. BCR-ABL siRNAs were encapsulated in the BCPVs by electrostatic force. Cell internalization was facilitated by the BCPV and assessed by confocal microscopy and flow cytometry. The regulation of the BCR-ABL level in K562 cells as a result of RNAi was analyzed by real-time polymerase chain reaction (RT-PCR). We observed that BCPV was able to form stable nanoplexes with siRNA molecules, even in the presence of fetal bovine serum (FBS), and successfully assisted in vitro siRNA transfection in the non-adherent K562 cells. As a consequence of downregulation of BCR-ABL, BCPV-siRNA nanoplexes inhibited cell proliferation and promoted cell apoptosis. All results were compared with a commercial transfection reagent, Lipofectamine2000 (TM), which served as a positive control. More importantly, this class of non-viral vector exhibits biodegradable features and negligible cytotoxicity, thus providing a versatile platform to deliver siRNA to non-adherent leukemia cells with high transfection efficiency by effectively overcoming extra-and intra-cellular barriers. Due to the excellent in vitro transfection results from BCPV-siRNA, a newly developed biodegradable transfection agent, BCPV, is being probed for transfection performance in an animal model.</P>

Improving Marine Policy through Use of Visualization Tools in a Policy Simulation Lab

James Opaluch,Thomas Grigalunas,Meifeng Luo,Huiting Zhang,권석재,정봉민,장영태 한국학술연구원 2002 Korea Observer Vol.33 No.2

Technical studies can shed light on many complex marinepolicy issues. However, conveying this information in easilyunderstandable ways to decision makers and other stakeholders isoften a difficult task. This paper will present initial draft results of ongoing work to develop new tools to help interested parties bettervisualize the consequences of policy actions and to integrate thetools into larger project analyses. The project uses the new stateof-the-art Policy Simulation Laboratory (SimLab) at the Univeristyof Rhode Island to communicate the consequences ofchange in the community. The SimLab is a group of networkedrooms and computer systems that utilize technology-based tools,like Geographic Information Systems (GIS), digital imagery andvirtual reality software, to help communities better visualize theconsequences of development (See http://www.uri.edu/cels/enre/Preview/SimLab/). For example, modeling tools can be used toforecast future development in a town, and GIS maps can be createdto show likely spatial distribution of future developments. Byclicking on specific areas of development on the maps, virtualreality tools allow interactive virtual drive-throughs or fly-bys ofdevelopments, complete with visuals and sound. Computer systemscan be used for forecast how different policy scenarios canbe used to attempt to manage the future of the community. In this paper we report on our initial progress toward thecreation and use of visualization tools, within the context of twolarger applications in coastal regions. The first application is partof a larger project to determine social, ecological and economicimpacts of alternative development scenarios in South County,Rhode Island. We intend to use virtual reality tools to help interestedparties better visualize the aesthetic consequences of newdevelopments. The second application is part of a larger ongoinganalysis to assess potential demand and community impacts of aproposed container port in Quonset Point, Rhode Island. We presentinitial drafts of technology-based tools to present visual andauditory impacts of a new port. Ongoing work will extend applicationsto coastal issues in Korea.

Slimy partners: the mucus barrier and gut microbiome in ulcerative colitis

Fang Jian,Wang Hui,Zhou Yuping,Zhang Hui,Zhou Huiting,Zhang Xiaohong 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Ulcerative colitis (UC) is a chronic recurrent intestinal inflammatory disease characterized by high incidence and young onset age. Recently, there have been some interesting findings in the pathogenesis of UC. The mucus barrier, which is composed of a mucin complex rich in O-glycosylation, not only provides nutrients and habitat for intestinal microbes but also orchestrates the taming of germs. In turn, the gut microbiota modulates the production and secretion of mucins and stratification of the mucus layers. Active bidirectional communication between the microbiota and its ‘slimy’ partner, the mucus barrier, seems to be a continually performed concerto, maintaining homeostasis of the gut ecological microenvironment. Any abnormalities may induce a disorder in the gut community, thereby causing inflammatory damage. Our review mainly focuses on the complicated communication between the mucus barrier and gut microbiome to explore a promising new avenue for UC therapy.

Use of Magnetic Resonance Neurography for Evaluating the Distribution and Patterns of Chronic Inflammatory Demyelinating Polyneuropathy

Xiaoyun Su,Xiangquan Kong,Zuneng Lu,Min Zhou,Jing Wang,Xiaoming Liu,Xiangchuang Kong,Huiting Zhang,Chuansheng Zheng 대한영상의학회 2020 Korean Journal of Radiology Vol.21 No.4

Objective: To evaluate the distribution and characteristics of peripheral nerve abnormalities in chronic inflammatory demyelinating polyneuropathy (CIDP) using magnetic resonance neurography (MRN) and to examine the diagnostic efficiency. Materials and Methods: Thirty-one CIDP patients and 21 controls underwent MR scans. Three-dimensional sampling perfections with application-optimized contrasts using different flip-angle evolutions and T1-/T2- weighted turbo spinecho sequences were performed for neurography of the brachial and lumbosacral (LS) plexus and cauda equina, respectively. Clinical data and scores of the inflammatory Rasch-built overall disability scale (I-RODS) in CIDP were obtained. Results: The bilateral extracranial vagus (n = 11), trigeminal (n = 12), and intercostal nerves (n = 10) were hypertrophic. Plexus hypertrophies were observed in the brachial plexus of 19 patients (61.3%) and in the LS plexus of 25 patients (80.6%). Patterns of hypertrophy included uniform hypertrophy (17 [54.8%] brachial plexuses and 21 [67.7%] LS plexuses), and multifocal fusiform hypertrophy (2 [6.5%] brachial plexuses and 4 [12.9%] LS plexuses) was present. Enlarged and/or contrast-enhanced cauda equina was found in 3 (9.7%) and 13 (41.9%) patients, respectively. Diameters of the brachial and LS nerve roots were significantly larger in CIDP than in controls (p < 0.001). The largest AUC was obtained for the L5 nerve. There were no significant differences in the course duration, I-RODS score, or diameter between patients with and without hypertrophy. Conclusion: MRN is useful for the assessment of distribution and characteristics of the peripheral nerves in CIDP. Compared to other regions, LS plexus neurography is more sensitive for CIDP.