Light-Chain Cardiac Amyloidosis: Cardiac Magnetic Resonance for Assessing Response to Chemotherapy

Guo Yubo,Li Xiao,Gao Yajuan,Shen Kaini,Lin Lu,Wang Jian,Cao Jian,Zhang Zhuoli,Wan Ke,Zhou Xi Yang,Chen Yucheng,Zhang Long Jiang,Li Jian,Wang Yining 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.5

Objective: Cardiac magnetic resonance (CMR) is a diagnostic tool that provides precise and reproducible information about cardiac structure, function, and tissue characterization, aiding in the monitoring of chemotherapy response in patients with lightchain cardiac amyloidosis (AL-CA). This study aimed to evaluate the feasibility of CMR in monitoring responses to chemotherapy in patients with AL-CA. Materials and Methods: In this prospective study, we enrolled 111 patients with AL-CA (50.5% male; median age, 54 [interquartile range, 49–63] years). Patients underwent longitudinal monitoring using biomarkers and CMR imaging. At followup after chemotherapy, patients were categorized into superior and inferior response groups based on their hematological and cardiac laboratory responses to chemotherapy. Changes in CMR findings across therapies and differences between response groups were analyzed. Results: Following chemotherapy (before vs. after), there were significant increases in myocardial T2 (43.6 ± 3.5 ms vs. 44.6 ± 4.1 ms; P = 0.008), recovery in right ventricular (RV) longitudinal strain (median of -9.6% vs. -11.7%; P = 0.031), and decrease in RV extracellular volume fraction (ECV) (median of 53.9% vs. 51.6%; P = 0.048). These changes were more pronounced in the superior-response group. Patients with superior cardiac laboratory response showed significantly greater reductions in RV ECV (-2.9% [interquartile range, -8.7%–1.1%] vs. 1.7% [-5.5%–7.1%]; P = 0.017) and left ventricular ECV (-2.0% [-6.0%–1.3%] vs. 2.0% [-3.0%–5.0%]; P = 0.01) compared with those with inferior response. Conclusion: Cardiac amyloid deposition can regress following chemotherapy in patients with AL-CA, particularly showing more prominent regression, possibly earlier, in the RV. CMR emerges as an effective tool for monitoring associated tissue characteristics and ventricular functional recovery in patients with AL-CA undergoing chemotherapy, thereby supporting its utility in treatment response assessment.

Further Results on Stabilization of Chaotic Systems Based on Fuzzy Memory Sampled-Data Control

Liu, Yajuan,Park, Ju H.,Guo, Bao-Zhu,Shu, Yanjun IEEE 2018 IEEE transactions on fuzzy systems Vol.26 No.2

<P>This note investigates sampled-data control for chaotic systems. A memory sampled-data control scheme that involves a constant signal transmission delay is employed for the first time to tackle the stabilization problem for Takagi–Sugeno fuzzy systems. The advantage of the constructed Lyapunov functional lies in the fact that it is neither necessarily positive on sampling intervals nor necessarily continuous at sampling instants. By introducing a modified Lyapunov functional that involves the state of a constant signal transmission delay, a delay-dependent stability criterion is derived so that the closed-loop system is asymptotically stable. The desired sampled-data controller can be achieved by solving a set of linear matrix inequalities. Compared with the existing results, a larger sampling period is obtained by this new approach. A simulation example is presented to illustrate the effectiveness and conservatism reduction of the proposed scheme.</P>

Nonfragile Exponential Synchronization of Delayed Complex Dynamical Networks With Memory Sampled-Data Control

Liu, Yajuan,Guo, Bao-Zhu,Park, Ju H.,Lee, Sang-Moon IEEE 2018 IEEE transactions on neural networks and learning Vol.29 No.1

<P>This paper considers nonfragile exponential synchronization for complex dynamical networks (CDNs) with time-varying coupling delay. The sampled-data feedback control, which is assumed to allow norm-bounded uncertainty and involves a constant signal transmission delay, is constructed for the first time in this paper. By constructing a suitable augmented Lyapunov function, and with the help of introduced integral inequalities and employing the convex combination technique, a sufficient condition is developed, such that the nonfragile exponential stability of the error system is guaranteed. As a result, for the case of sampled-data control free of norm-bound uncertainties, some sufficient conditions of sampled-data synchronization criteria for the CDNs with time-varying coupling delay are presented. As the formulations are in the framework of linear matrix inequality, these conditions can be easily solved and implemented. Two illustrative examples are presented to demonstrate the effectiveness and merits of the proposed feedback control.</P>

Results on stability of linear systems with time varying delay

Liu, Yajuan,H. Park, Ju,Guo, Bao-Zhu IET 2017 IET CONTROL THEORY AND APPLICATIONS Vol.11 No.1

<P>The integral inequality approach has been widely used to obtain delay-dependent stability criteria for dynamic systems with delays, and finding integral inequalities for quadratic functions hence plays a key role in reducing conservatism of corresponding stability conditions. In this study, an improved integral inequality which covers several well-known integral inequalities is introduced, and improves thereby stability for linear systems with time-varying delay. Three numerical examples are given to demonstrate the effectiveness and superiority of the proposed method.</P>

Characterization of the fluoridating process of hydroxyapatite

Xiao-liang Guo,Qun-li Rao,Ling-ling Li,Yajuan Zou,Chengchei Wu 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.8

F-substituted hydroxyapatites were synthesized by chemical precipitation method using Ca(CH3COO)2·H2O and KH2PO4 asreactants and KF·2H2O as fluorination agent. Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD) andX-ray fluorescence spectrometer (XRF) were used to characterize samples. The results showed that the more fluorine wasadded the more OH ions replaced by F. Moreover, OH-F bond was formed between crystalline, and the bond was strongerthan that of original OH-OH, so the grains of hydroxyapatite grew larger and the crystallinity increased as F content increased.

Densifi cation of matrix graphite for spherical fuel elements used in molten salt reactor via addition of green pitch coke

Zhao He,Hongchao Zhao,Jinliang Song,Xiaohui Guo,Zhanjun Liu,Yajuan Zhong,T. James Marrow 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.4

Green pitch coke with an average particle size of 2 mm was adopted as densifier and added to the rawmaterials of conventional A3-3 matrix graphite (MG) to prepare modified A3-3 matrix graphite (MMG)by the quasi-isostatic molding method. The structure, mechanical and thermal properties were assessed. Compared with MG, MMG had a more compact structure, and exhibited improved properties of highermechanical strength, higher thermal conductivity and better molten salt barrier performance. Notably,under the same infiltration pressure of 5 atm, the fluoride salt occupation of MMG was only 0.26 wt%,whereas it was 15.82 wt% for MG. The densification effect of green pitch coke endowed MMG withimproved properties for potential use in the spherical fuel elements of molten salt reactor.

Interactive Effects of Ultraviolet Radiation and Dissolved Organic Carbon on Phytoplankton Growth and Photosynthesis in Sanya Bay, Northern South China Sea

Jianzu Liao,Weihua Zhou,Jie Xu,Xiangcheng Yuan,Yuxian Liang,Yajuan Guo,Hui Huang,Sheng Liu,Aimin Long 한국해양과학기술원 2019 Ocean science journal Vol.54 No.4

The effects of a simulated climate change scenario, i.e., increased ultraviolet radiation (UVR) and dissolved organic carbon (DOC), on the growth and photosynthesis of tropical coastal phytoplankton were evaluated in Sanya Bay, northern South China Sea, in summer. Microcosm experiments were conducted at two contrasting stations (Stns S1 and S2) with three different UVR treatments and two DOC addition treatments. Our results showed that natural sunlight UVR or increased UV-B did not affect phytoplankton biomass and primary production. However, increased UV-B significantly decreased the proportion of picophytoplankton and the efficiency of carbon fixation at Stn S2. DOC enhancement caused negative effects on primary production under natural sunlight UVR only at Stn S1. Interactive effects of UVR and DOC addition on phytoplankton biomass and primary production were detected at Stn S1, due to the negative effects of DOC being eliminated under the increased UV-B condition. The lack of interactive effects at Stn S2 were likely due to the differences with Stn S1 in terms of light acclimation and biological interaction. In summary, this future climate change scenario will probably not affect the photosynthetic CO2 fixation and biomass of natural phytoplankton in Sanya Bay.