Biruloquinone, an Acetylcholinesterase Inhibitor Produced by Lichen-Forming Fungus Cladonia macilenta

( Luo Heng ),( Chang Tian Li ),( Jin Cheol Kim ),( Yan Peng Liu ),( Jae Sung Jung ),( Young Jin Koh ),( Jae Seoun Hur ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.2

At present, acetylcholinesterase (AChE) inhibitors are the first group of drugs to treat mild to moderate Alzheimer`s disease (AD). Although beneficial in improving cognitive and behavioral symptoms, the effectiveness of AChE inhibitors has been questioned since they do not delay or prevent neurodegeneration in AD patients. Therefore, in the present study, in order to develop new and effective anti-AD agents from lichen products, both the AChE inhibitory and the neuroprotective effects were evaluated. The AChE inhibitory assay was performed based on Ellman`s reaction, and the neuroprotective effect was evaluated by using the MTT method on injured PC12 cells. One AChE inhibitor (IC50 = 27.1 μg/ml) was isolated by means of bioactivity-guided isolation from the extract of lichen-forming fungus Cladonia macilenta, which showed the most potent AChE inhibitory activity in previous screening experiment. It was then identified as biruloquinone by MS, and 1H- and 13C-NMR analyses. The inhibitory kinetic assay suggested that biruloquinone is a mixed-II inhibitor on AChE. Meanwhile, biruloquinone improved the viability of the H2O2- and β-amyloid-injured PC12 cells at 1 to 25 μg/ml. The protective effects are proposed to be related to the potent antioxidant activities of biruloquinone. These results imply that biruloquinone has the potential to be developed as a multifunctional anti- AD agent.

Fault Detection Observer Design for Fuzzy Systems with Local Nonlinear Models via Fuzzy Lyapunov Function

Guojun Liu,Xiao-Heng Chang,Yong-Yan Cao 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5

This paper concerns with the problem of designing fault detection (FD) observer for Takagi-Sugeno (TS)fuzzy systems subject to local nonlinear models. Different from the quadratic Lyapunov function approaches,fuzzy Lyapunov function approach is applied to design the fault detection observer, and corresponding sufficientconditions are given in terms of linear matrix inequalities. In addition, combined with nonlinear local modelsscheme and slack variable technique, the T-S fuzzy systems have fewer fuzzy rules to reduce the computationalburden. Compared with the existing results, less conservative results on existence of fuzzy fault detection observersare derived. Moreover, the designed fuzzy fault detection observer not only guarantees the residual system stabilitybut also improves the H_ index estimation. It is noted that the H_ index is employed to measure the worst-cast faultsensitivity performance. Finally, a numerical simulation is given to illustrate the effectiveness of the designed faultdetection observer.

Learning Curve of ROSA ONE Spine System for Transpedicular Screw Placement

Bing-Hung Hsu,Heng-Wei Liu,Kha-Liang Lee,Ming-Chin Lin,Gao Chen,Jang Yu,Chiao-Ling Chen,I-Chang Su,Chien-Min Lin 대한척추신경외과학회 2022 Neurospine Vol.19 No.2

Objective: The study investigated our institutional learning curve for the ROSA ONE spine system (ROSA) based on ROSA usage time. Methods: ROSA was designed to provide high accuracy for spinal pedicle screw placement through a built-in tracking technique. This study was conducted from November 2018 to January 2021. The time taken to complete each step of the robotic workflow was recorded. Patient demographics, comorbidities, surgical indications, and number of screw placements were examined in subgroup analysis. The Curve Fitting-General package (a part of NCSS 2021 software) was used to fit a mathematical model to the learning curve. Patient demographics, imaging data, and surgical time were reviewed retrospectively. Results: A total of 167 patients who had undergone surgery were included. The mean total ROSA usage time was 107.1 ± 27.3 minutes. The estimated learning rate was 90.4%, and the largest slope change occurred close to the time of the 20th surgery. The observed overall learning trend in the 4-screw group could be attributed to screw planning. The presence of scoliosis (p = 0.73) or spondylolisthesis (p = 0.70) did not significantly influence the mean total time (TT) for all patients; however, the mean TT differed significantly (p < 0.01) among subgroups stratified by body mass index, screw number placement, and thoracic spine involvement. Conclusion: To the best of our knowledge, this is the first study to examine the learning curve for the various crucial steps of ROSA-guided pedicle screw placement. The indicative learning curve involved 20 patients who had undergone surgery.

Synthesis and thermal properties of urethane-containing epoxy resin

Fan-Long Jin,Heng-Chang Liu,Baoqing Yang,박수진 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.24 No.-

A urethane-containing epoxy resin was successfully synthesized by reacting bisphenol A with 1,6- hexamethylene diisocyanate and epichlorohydrin. The chemical structure of urethane-containing epoxy resin was confirmed using FT-IR, 1HNMR, and elemental analysis. DSC results indicated that the initial curing and maximum exothermic peak temperatures of urethane-containing epoxy resin cured with 4,40-diaminodiphenylmethane were 60 8C and 135 8C, respectively; these values were lower than those of a bisphenol A-based epoxy resin. The thermal stability of epoxy resins was studied using TGA, and it was found that the degradation temperature of urethane-containing epoxy resin was lower than that of bisphenol A-based epoxy resin under the same conditions.

Fracture toughness improvement of epoxy resins with short carbon fibers

Wei Dong,Fan-Long Jin,박수진,Heng-Chang Liu 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

This study examined the thermal stability and fracture toughness of diglycidylether of bisphenol-A (DGEBA)/short carbon fiber (SCF) composites using several techniques. The thermal stability of the DGEBA/SCF composites was similar to that of neat epoxy resin. The fracture toughness of the composites was significantly improved relative to the neat resin. The SEM micrographs indicated that a relatively rough surface with shear deformation and tortuous cracks was formed, thereby preventing deformation and crack propagation and inducing higher fracture toughness in the DGEBA/SCF composites.

A critical review on ammonium recovery from wastewater for sustainable wastewater management

Ye, Yuanyao,Ngo, Huu Hao,Guo, Wenshan,Liu, Yiwen,Chang, Soon Woong,Nguyen, Dinh Duc,Liang, Heng,Wang, Jie Elsevier 2018 Bioresource technology Vol.268 No.-

<P><B>Abstract</B></P> <P>The growing global population’s demand for ammonium has triggered an increase in its supply, given that ammonium plays a crucial role in fertilizer production for the purpose of food security. Currently, ammonia used in fertilizer production is put through what is known as the industrial Haber Bosch process, but this approach is substantially expensive and requires much energy. For this reason, looking for effective methods to recover ammonium is important for environmental sustainability. One of the greatest opportunities for ammonium recovery occurs in wastewater treatment plants due to wastewater containing a large quantity of ammonium ions. The comprehensively and critically review studies on ammonium recovery conducted, have the potential to be applied in current wastewater treatment operations. Technologies and their ammonium recovery mechanisms are included in this review. Furthermore the economic feasibility of such processes is analysed. Possible future directions for ammonium recovery from wastewater are suggested.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Growing global population ultimately calls for ammonium recovery. </LI> <LI> Wastewater is considered as the renewable resource for the ammonium recovery. </LI> <LI> The bioelectrochemical system can efficiently and effectively recover ammonium. </LI> <LI> Mechanism and technology of ammonium recovery were summarized. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>