DEPTH FOR TRIANGULATED CATEGORIES

Liu, Yanping,Liu, Zhongkui,Yang, Xiaoyan Korean Mathematical Society 2016 대한수학회보 Vol.53 No.2

Recently a construction of local cohomology functors for compactly generated triangulated categories admitting small coproducts is introduced and studied by Benson, Iyengar, Krause, Asadollahi and their coauthors. Following their idea, we introduce the depth of objects in such triangulated categories and get that when (R, m) is a graded-commutative Noetherian local ring, the depth of every cohomologically bounded and cohomologically finite object is not larger than its dimension.

The CREG1-FBXO27-LAMP2 axis alleviates diabetic cardiomyopathy by promoting autophagy in cardiomyocytes

Liu Dan,Xing Ruinan,Zhang Quanyu,Tian Xiaoxiang,Qi Yanping,Song Haixu,Liu Yanxia,Yu Haibo,Zhang Xiaolin,Jing Quanmin,Yan Chenghui,Han Yaling 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Autophagy plays an important role in the development of diabetic cardiomyopathy. Cellular repressor of E1A-stimulated genes 1 (CREG1) is an important myocardial protective factor. The aim of this study was to investigate the effects and mechanisms of CREG1 in diabetic cardiomyopathy. Male C57BL/6 J mice, Creg1 transgenic mice and cardiac-specific knockout mice were used to establish a type 2 diabetes model. Small animal ultrasound, Masson’s staining and western blotting were used to evaluate cardiac function, myocardial fibrosis and autophagy. Neonatal mouse cardiomyocytes (NMCMs) were stimulated with palmitate, and the effects of CREG1 on NMCMs autophagy were examined. CREG1 deficiency exacerbated cardiac dysfunction, cardiac hypertrophy and fibrosis in mice with diabetic cardiomyopathy, which was accompanied by exacerbated autophagy dysfunction. CREG1 overexpression improved cardiac function and ameliorated cardiac hypertrophy and fibrosis in diabetic cardiomyopathy by improving autophagy. CREG1 protein expression was decreased in palmitate-induced NMCMs. CREG1 knockdown exacerbated cardiomyocyte hypertrophy and inhibited autophagy. CREG1 overexpression inhibited cardiomyocyte hypertrophy and improved autophagy. LAMP2 overexpression reversed the effect of CREG1 knockdown on palmitate-induced inhibition of cardiomyocyte autophagy. CREG1 inhibited LAMP2 protein degradation by inhibiting the protein expression of F-box protein 27 (FBXO27). Our findings indicate new roles of CREG1 in the development of diabetic cardiomyopathy.

Magnetically Recoverable Nanoflake-Shaped Iron Oxide/Pt Heterogeneous Catalysts and Their Excellent Catalytic Performance in the Hydrogenation Reaction

Liu, Yanping,Chung, Jooyoung,Jang, Youngjin,Mao, Shuai,Kim, B. Moon,Wang, Yongqaing,Guo, Xiaohui American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.3

<P>In this study, a kind of unique Fe<SUB>2</SUB>O<SUB>3</SUB>/Pt hybrid consisting of uniform platinum nanoparticles deposited on a nanoflake-shaped Fe<SUB>2</SUB>O<SUB>3</SUB> support was prepared by using a solvothermal reaction followed by a heat-induced reduction process. The prepared Fe<SUB>2</SUB>O<SUB>3</SUB> sample displays well-defined nanoflake-like morphology; remarkably, there are many specific cavities on its surface. In addition, uniform Pt nanoparticles with narrow size distribution were deposited onto the surface of the preformed flake-like Fe<SUB>2</SUB>O<SUB>3</SUB> support to form the Fe<SUB>2</SUB>O<SUB>3</SUB>/Pt hybrid via a facile heat-induced reduction reaction. Thus, the prepared Fe<SUB>2</SUB>O<SUB>3</SUB>/Pt hybrid can serve as heterogeneous catalyst over the hydrogenation reaction. Results demonstrated that the specific Fe<SUB>2</SUB>O<SUB>3</SUB>/Pt heterogeneous catalyst exhibits good catalytic performances, including high conversion, specific selectivity, and excellent recycling durability, over hydrogenation reactions for different substrates. Furthermore, the prepared Fe<SUB>2</SUB>O<SUB>3</SUB>/Pt heterogeneous catalyst could be easily separated from the product mixture by using a magnet and could be recycled for 10 cycles without catalytic activity loss. In a word, the present synthetic approach is facile, scalable, and reproducible, which can be easily facilitated to prepare other types of noble metals/metal oxide composite systems.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-3/am404904p/production/images/medium/am-2013-04904p_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am404904p'>ACS Electronic Supporting Info</A></P>

Depth for triangulated categories

Yanping Liu,Zhongkui Liu,Xiaoyan Yang 대한수학회 2016 대한수학회보 Vol.53 No.2

Recently a construction of local cohomology functors for compactly generated triangulated categories admitting small coproducts is introduced and studied by Benson, Iyengar, Krause, Asadollahi and their coauthors. Following their idea, we introduce the depth of objects in such triangulated categories and get that when $(R,\mathfrak{m})$ is a graded-commutative Noetherian local ring, the depth of every cohomologically bounded and cohomologically finite object is not larger than its dimension.

The Complete Oxidation of Ethanol at Low Temperature over a Novel Pd–Ce/γ-Al2O3–TiO2 Catalyst

Yanping Wang,Jinshuang Zhao,Xiaoli Wang,Zhe Li,Pengfei Liu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.8

Pd–Ce/γ-Al2O3–TiO2 catalysts were prepared by combined sol–gel and impregnation methods. Transmission electron microscopy, X-ray diffraction, H2-temperature-programmed reduction, O2-temperature-programmed desorption, and ethanol oxidation experiments were conducted to determine the properties of the catalysts. Addition of an optimal amount of Ce improved the performance of the Pd/γ-Al2O3–TiO2 catalyst in promoting the complete oxidation of ethanol. The catalyst with 1% Ce exhibited the highest activity, and catalyzed complete oxidation of ethanol at 175 °C; its selectivity to CO2 reached 87%. Characterization results show that addition of appropriate amount of Ce could enrich the PdO species, and weaken the Pd–O bonds, thus enhancing oxidation ability of the catalyst. Meanwhile, the introduction of CeO2 could make PdO better dispersed on γ-Al2O3–TiO2, which is beneficial for the improvement of the catalytic oxidation activity.

Thermal, Mechanical and Rheological Properties of Poly(lactic acid) Chain Extended with Polyaryl Polymethylene Isocyanate

Yanping Hao,Yi Li,Zhigang Liu,Xiangyu Yan,Yi Tong,Huiliang Zhang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.9

In this study, polyaryl polymethylene isocyanate (PAPI) was used as a chain extender for poly(lactic acid) (PLA)to produce a high molecular weight material with better rheological, thermal and mechanical properties. The reactionbetween PLA chains and PAPI was proved by FTIR during reactive blending. The results showed that the molecular weightand molecular weight distribution were increased with the addition of PAPI content due to the chain extension. Chainextension was also responsible for the increased modulus and complex viscosity. The glass transition temperature (Tg) andthermal stability increased by incorporating with PAPI. The results of mechanical properties showed that a considerablyhigher tensile strength and Young’s modulus of the reactive blends compared with neat PLA.

The hopping variable range conduction in amorphous InAs thin films

Yanping Yao,Baoxue Bo,Chunling Liu 한국물리학회 2018 Current Applied Physics Vol.18 No.12

This paper studies the influence of temperature on electrical resistivity in α-InAs thin films between 30 K-2K based on the analysis of Mott VRH model and ES VRH model. The effect of the interactions between electrons at lower temperature must be considered, therefore, ES VRH conduction will dominate mechanism, and the crossover from Mott to ES VRH conduction is observed about 7 K. Based on available experiment data and VRH conduction model, the parameters of VRH conduction are determined. And the calculated values of TC are consistent with the experimental results. In addition, RM/ξ, ΔM/kT, RES/ξ and ΔES/kT are satisfied with the validity of Mott and ES models. Furthermore, the temperature dependence of resistivity at low temperature obeys a universal scaling law, which well describes the overall temperature range of VRH conduction. However, the values of T’ M from the universal function are two order of magnitudes lower than TM deduced from fitting experiment.

An Improved Tet-on System to Tightly Conditionally Regulate Reporter Gene Expression

Yanping Ren,Xiangping Li,Qingyou Liu,Yanfei Deng,Deshun Shi 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.1

Reporter genes are often used as markers totrack the integration and expression of target genes inanimal genetic engineering. To avoid potential side effectsfrom reporter genes, in this study an improved Tet-onsystem was developed to control reporter gene expression,and its effectiveness was explored in transgenic cells. First,the rtTA protein was fused with Tat and NLS proteins toobtain the prokaryotic expression vector pET32a-Tat-rtTANSL. A eukaryotic transgenic vector was constructed, p-HS4-BPA-TmA-HS4, in which the reporter (mCherry) andtarget (PRL) genes were promoted by TRE and BCN,respectively. After confirming the functionality of thetransgenic vector, purified rtTA protein and Dox wereadded to induce expression of the mCherry gene. Theoptimal amount of purified rtTA protein, its influence ontarget gene expression, and the time of rtTA protein actionwere each investigated separately. The results showed thatrtTA protein was expressed in transformed E. coli with IPTGinduction. TRE could promote mCherry gene expressionby co-transfecting the constructed transgenic vector andprtTA plasmid. When purified rtTA protein and Dox wereadded, red fluorescence was observed in Bcap-37 cellstransfected with the p-HS4-BPA-TmA-HS4 vector, and theexogenous PRL gene was expressed regardless of mCherrygene expression. The optimal amount of rtTA protein was16 μg/mL, and it needed about 6 h to promote mCherrygene expression in transfected cells. These resultsdemonstrate that the expression of the mCherry reportergene can be tightly and conditionally regulated by our Tetonsystem.

Influence of Crosslinking on Rheological Properties, Crystallization Behavior and Thermal Stability of Poly(lactic acid)

Yanping Hao,Fan Wang,Yang Liu,Xue Ai,Hongchi Tian 한국섬유공학회 2022 Fibers and polymers Vol.23 No.7

In this study, a series of crosslinked poly(lactic acid) (PLA) with different gel fractions were obtained by addingsmall amounts of bis(tert-butyl dioxy isopropyl) benzene (BIBP) and triallyl isocyanurate (TAIC). The rheological properties,crystallization behavior and thermal stability of all samples were investigated. The results showed that some crosslinkedstructures were formed according to the gel fraction and the molecular weight. The crosslinked structures were alsoresponsible for the increased modulus and complex viscosity, which extended its processing methods, such as foaming andfilm blowing. And different relaxation processes were observed for different samples by Han and Cole-Cole plots. Moreover,the results showed that the crosslinked structures played the role of nucleation site for the blends, which enhance thecrystallization temperature (Tc). The glass transition temperature (Tg) and melt temperature (Tm) gradually decreased withincreasing gel fraction. Crosslinking also had the positive effect on the thermal stability of PLA.

Electrical conduction mechanism and photon-generated carrier recombination process in amorphous InSb films

Yanping Yao,Chunling Liu,Haidong Qi,Xi Chang,Chunwu Wang,Guangde Wang 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Temperature dependence of dark conductivity and photoconductivity has been studied in amorphous InSb thin films in the temperature range of 120―300 K. The experimental data suggest that conduction in the high temperature range occurs in the extended states; conduction in the intermediate temperature range is due to thermally assisted tunneling of charge carriers in localized states near the band edge; while conduction in low temperature range takes place through variable range hopping of charge carriers in the localized states near the Fermi level. The temperature dependence of photoconductivity shows that the temperature region is divided into two regions.Moreover the result of intensity dependence of steady state photoconductivity indicates that bimolecular recombination at high temperatures and monomolecular at low temperatures in amorphous InSb thin films.