Inhibition of α-glucosidase by 2-thiobarbituric acid: Molecular dynamics simulation integrating parabolic noncompetitive inhibition kinetics

Qin, Xiu-Yuan,Lee, Jinhyuk,Zheng, Li,Yang, Jun-Mo,Gong, Yan,Park, Yong-Doo Elsevier 2018 Process biochemistry Vol.65 No.-

<P><B>Abstract</B></P> <P>The phenomenon of α-glucosidase inhibition has attracted the attention of researchers due to its association with type 2 diabetes treatment in humans. In this study, we found that 2-thiobarbituric acid (TBA) induces complex inhibition of α-glucosidase using kinetics tests and molecular dynamics (MD) simulations. Computational MD and docking simulations demonstrate that TBA interacts with three residues on active sites of α-glucosidase such as Met69, Arg212, and His348. These biochemical tests indicate that TBA reversibly inhibits α-glucosidase in a parabolic noncompetitive manner (<I>IC</I> <SUB>50</SUB> =17.13±1.14mM; <I>K</I> <SUB>i</SUB> =13.25±0.56mM) and that this inhibition is accompanied by a biphasic kinetic process. The tertiary conformational changes were not synchronized with TBA inhibition but we observed hydrophobic disruption after inactivation at higher concentrations of TBA. Our results provide insight into the functional roles of residues located at the active sites of α-glucosidase, and we suggest that compounds similar to TBA (heterocyclic compounds) targeting the key residues of active sites are potential α-glucosidase inhibitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 2-Thiobarbituric acid (TBA) induces complex inhibition of α-glucosidase. </LI> <LI> Computational MD simulations demonstrate that TBA interacts with Met69, Arg212, and His348. </LI> <LI> TBA reversibly inhibits α-glucosidase in a parabolic noncompetitive manner (<I>IC</I> <SUB>50</SUB> =17.13±1.14mM; <I>K</I> <SUB>i</SUB> =13.25±0.56mM). </LI> <LI> The high dose of TBA induces hydrophobic disruption after inactivation. </LI> <LI> Heterocyclic compounds targeting the key residues of active sites are potential α-glucosidase inhibitors. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis of rod-like titanium doped hydroxyapatite nanopowder

Li-li Wang,Xiu-feng Wang,Cheng-long Yu,Yan-qi Zhao 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.6

Rod-like titanium doped hydroxyapatite (Ti-doped HA) nanopowder was synthesized using Ca(NO3)2 • 4H2O, (NH4)2HPO4 and tetraethylorthotitanate as precursor materials via a combination of chemical co-precipitation and microwave techniques route. The effect of the content of titanium in Ti-doped HA (0.2-2.4 wt.%) on sintering behavior, crystal size, shape and morphology was investigated. The results suggested that the addition of titanium to HA structure did restrain HA decomposition and thermal reaction between HA and titanium, which resulted in improved thermal stability of HA at high sintering temperature. The grain size of sintered Ti-doped HA, which was much smaller than that of pure HA. 0.8 wt.% addition of titanium to HA, was optimum for producing nanometer-sized rod-like Ti-doped HA crystal with improved thermal stability.

A novel inverse opal zirconia pigment with controllable color saturation

Li-li Wang,Xin-xin Liu,Xiao-peng Li,Xiu-feng Wang,Li-na Feng,Xu-ri Hou 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.2

The inverse opal zirconia pigments were prepared by template method using polystyrene microspheres with the size of 340 ± 10nm as raw material and the in situ carbon was formed to achieve controllable and adjustable color saturation by sintering atvarious temperatures in nitrogen atmosphere with various nitrogen flow rates. The effects of nitrogen atmosphere, nitrogenflow rate and sintering temperature on the morphology, phase and color saturation of the inverse opal zirconia wereinvestigated. The results showed that when the inverse opal zirconia was sintered at 450 oC to 600 oC in nitrogen atmosphere,the green color saturation could be adjusted by changing the nitrogen flow rate from 0.2 L/min to 0.8 L/min. When thenitrogen rate was 0.8L/min, the green color saturation of the inverse opal zirconia could be adjusted by changing the sinteringtemperature from 450 oC to 600 oC. It indicated that the more the amount of in-situ carbon was generated, the more stray lightwas absorbed and the higher green color saturation of the inverse opal zirconia could be obtained. Further increasing thesintering temperature to 700 oC would destroy the inverse opal morphology of zirconia and affect the carbonization of theorganic component.

JCAD deficiency attenuates activation of hepatic stellate cells and cholestatic fibrosis

Li Xie,Hui Chen,Li Zhang,Yue Ma,Yuan Zhou,Yong-Yu Yang,Chang Liu,Yu-Li Wang,Ya-Jun Yan,Jia Ding,Xiao Teng,Qiang Yang,Xiu-Ping Liu,Jian Wu 대한간학회 2024 Clinical and Molecular Hepatology(대한간학회지) Vol.30 No.2

Background/Aims: Cholestatic liver diseases including primary biliary cholangitis (PBC) are associated with active hepatic fibrogenesis, which ultimately progresses to cirrhosis. Activated hepatic stellate cells (HSCs) are the main fibrogenic effectors in response to cholangiocyte damage. JCAD regulates cell proliferation and malignant transformation in nonalcoholic steatoheaptitis-associated hepatocellular carcinoma (NASH-HCC). However, its participation in cholestatic fibrosis has not been explored yet. Methods: Serial sections of liver tissue of PBC patients were stained with immunofluorescence. Hepatic fibrosis was induced by bile duct ligation (BDL) in wild-type (WT), global JCAD knockout mice (JCAD-KO) and HSC-specific JCAD knockout mice (HSC-JCAD-KO), and evaluated by histopathology and biochemical tests. In situ-activated HSCs isolated from BDL mice were used to determine effects of JCAD on HSC activation. Results: In consistence with staining of liver sections from PBC patients, immunofluorescent staining revealed that JCAD expression was identified in smooth muscle α-actin (α-SMA)-positive fibroblast-like cells and was significantly up-regulated in WT mice with BDL. JCAD deficiency remarkably ameliorated BDL-induced hepatic injury and fibrosis, as documented by liver hydroxyproline content, when compared to WT mice with BDL. Histopathologically, collagen deposition was dramatically reduced in both JCAD-KO and HSC-JCAD-KO mice compared to WT mice, as visualized by Trichrome staining and semi-quantitative scores. Moreover, JCAD deprivation significantly attenuated in situ HSC activation and reduced expression of fibrotic genes after BDL. Conclusions: JCAD deficiency effectively suppressed hepatic fibrosis induced by BDL in mice, and the underlying mechanisms are largely through suppressed Hippo-YAP signaling activity in HSCs.

Improved Recursive-gradient-based Model-free Adaptive Control Algorithm

Xiu-Ying Li,Jian Wang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.11

In this paper, the improved recursive-gradient-based model-free adaptive control algorithm is investigated where a momentum term is added in the form of parameter’s change at the previous moment. It is that not only the direction but also the amplitude of the gradient descent are considered, the convergence speed of the algorithm is accelerated and therefore the dynamic performance of the system is enhanced. By rigorous mathematical induction, the convergence of output tracking error and the BIBO stability of the closed-loop system are proved. Simulation results demonstrate the effectiveness and feasibility of the proposed algorithm.

The Numerical Simulation of Unsteady Flow in a Mixed flow Pump Guide Vane

Li, Yi-Bin,Li, Ren-Nian,Wang, Xiu-Yong Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.4

In order to investigate the characteristics of unsteady flow in a mixed flow pump guide vane under the small flow conditions, several indicator points in a mixed flow pump guide vane was set, the three-dimensional unsteady turbulence numerical value of the mixed flow pump which is in the whole flow field will be calculated by means of the large eddy simulation (LES), sub-grid scale model and sliding mesh technology. The experimental results suggest that the large eddy simulation can estimate the positive slope characteristic of head & capacity curve. And the calculation results show that the pressure fluctuation coefficients of the middle section in guide vane inlet will decrease firstly and then increase. In guide vane outlet, the pressure fluctuation coefficients of section will be approximately axially symmetrical distribution. The pressure fluctuation minimum of section in guide vane inlet is above the middle location of the guide vane suction surface, and the pressure fluctuation minimum of section in which located the middle and outlet of guide vane. When it is under the small flow operating condition, the eddy scale of guide vane is larger, and the pressure fluctuation of the channel in guide vane being cyclical fluctuations obviously which leads to the area of eddy expanding to the whole channel from the suction side. The middle of the guide vane suction surface of the minimum amplitude pressure fluctuation to which the vortex core of eddy scale whose direction of fluid's rotation is the same to impeller in the guide vane adhere.

Influence of host plants on the development, survivorship, and fecundity of the summer fruit tortrix moth, Adoxophyes orana (Lepidoptera: Tortricidae)

Li Guang‐wei,Wang Hui‐min,Yang Wen‐tao,Chen Xiu‐lin,Li Bo‐liao,Chen Yu‐xin 한국곤충학회 2021 Entomological Research Vol.51 No.10

The summer fruit tortrix moth Adoxophyes orana is a seriously damaged leaf roller pest for fruit trees. In this study, we evaluated the effect of five host plants (apple, Malus domestica B.; peach, Prunus persica var. nectarina; apricot, Armeniaca vulgaris Lam.; mulberry, Morus alba L.; and jujube, Ziziphus jujuba M.) on the development, survival, and fecundity of A. orana under laboratory conditions. Results showed that the development times of A. orana on jujube were significantly longer than those on the other four plants. The preimaginal survival rate was influenced by the host plants, which were fed during the larval stage, and with the highest on peach, followed by apple, apricot, and mulberry, and with the lowest on jujube. Adult females from larvae reared on apricot laid the greatest numbers of eggs (318.11 eggs per female), while that on apple, jujube, and mulberry was smaller, and no significant difference was observed among them. The highest intrinsic rate of increase (rm) was observed on peach and apricot; these two fruit trees were considered to be the most suitable host plant for A. orana because of the shorter developmental duration, higher survival rate, and the highest fecundity.

Response Modification Factor and Displacement Amplification Factor of Y-Shaped Eccentrically Braced High-Strength Steel Frames

Li Shen,Li Rong-Rong,Wang De-Fa,Pan Xiu-Zhen,Guo Hong-Chao 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.5

A Y-shaped eccentrically braced high-strength steel frame is a novel structure. For such structure to exhibit good plastic deformation ability under severe earthquake, the links are made of ordinary steel ( f y ≤ 345 MPa), whereas high-strength steel ( f y ≥ 460 MPa) is used in the frame beam and column to reduce the cross section while ensuring the elasticity of the non-energy consuming component. The new structure has good ductility and energy-dissipating capacity. The response modifi cation factor R is crucial to the performance-based seismic design. For an appropriate and economical seismic design, the R value should be reasonably selected. In the 2016 edition of China's code for Seismic Design of Buildings (GB50011- 2010), it is obviously not reasonable to hide the R concept and adopt a constant value for all structural systems. It is important to study R and C d of a Y-shaped eccentrically braced high-strength steel frame, it can not only improve the structural performance design, but also provide reference for the future, and promotes the application of the structure in seismic areas, which presents excellent seismic performance. Therefore, in this study, structures with diff erent stories (4, 8, 12, and 16 stories) and link lengths (700, 900, and 1100 mm) were designed via the performance-based seismic design method. A static elastic–plastic analysis (Pushover analysis) and an incremental dynamic analysis (IDA) were conducted and the data thus obtained was fi tted to reach the IDA performance curve of the structure. The R and C d value of each prototype were calculated using the capability spectrum method, the number of structural story N and the link length e is considered. The results of the pushover analysis and IDA were compared; the values of each performance coeffi cient obtained can serve as a reference for the performance design of the new structural systems in the future.

Properties of an AlGaN/AlN Distributed-Bragg-reflector Structure

Li-Li Zhang,Zhan-Hui Liu,Xiao-Gu Huang,Qing-Fang Li,Rong Zhang,Zi-Li Xie,Xiang-Qian Xiu 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.7

An AlGaN/AlN distributed-Bragg-reflector (DBR) structure with a high Al content was grown byusing plasma-assisted molecular beam epitaxy (PA-MBE). The properties of the sample were characterizedby using the transmission electron microscopy, high-resolution X-ray diffraction, atomicforce microscopy, and reflectivity spectrum measurements. The reciprocal space mapping analysisindicated that the strain in the AlGaN layers was partially relaxed. The morphology of the DBRexhibited a surface covered by grains (average size of about 130 nm), and the surface roughness wasabout 2 nm. The spectral measurements showed that the DBR structure presented a peak reflectivityof 68.8% at the center wavelength of 247 nm, which indicated that this DBR structure couldwork in the deep solar-blind UV region with acceptable reflectivity. However, the optical propertiesof the DBR structure were deteriorated by the fluctuation of the Al composition, non-uniformity ofthe layer thickness, the blurry, rough interface in the DBR structure, and so on.

Genome of Betaproteobacterium Caenimonas sp. Strain SL110 Contains a Coenzyme F420 Biosynthesis Gene Cluster

( Xiu Ling Li ),( Fu Ying Feng ),( Yong Hui Zeng ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.11

To probe the genomic properties of microbes thriving in desert lakes, we sequenced the full genome of a betaproteobacterial strain (SL110) belonging to the understudied genus Caenimonas of the family Comamonadaceae. This strain was isolated from a freshwater lake in the western Gobi Desert, Northern China. Its genome contains genes encoding carbon monoxide dehydrogenase, nitrate reductase, nitrite reductase, nitric oxide reductase, and sulfur oxidation enzymes, highlighting the potentially important contribution of this group of bacteria to the cycling of inorganic elements in nature. Unexpectedly, a coenzyme F420 biosynthesis gene cluster was identified. A further search for F420 biosynthesis gene homologs in genomic databases suggests the possible widespread presence of F420 biosynthesis gene clusters in proteobacterial genomes.