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| 1 | Third-order point contact approach for five-axis sculptured surface machining using non-ball-end tools(II): Tool positioning strategy显示文摘Based on the mathematical model describing the third-order approximation of the cutter envelope surface according to one given cutter location(CL),a tool positioning strategy is proposed for efficiently machining free-form surfaces with non-ball-end cutters.The optimal CL is obtained by adjusting the inclination and tilt angles of the cutter until its envelope surface and the design surface have the third-order contact at the cutter contact(CC)point,which results in a wide machining strip.The strategy can handle the constraints of machine joint angle limits,global collision avoidance and tool path smoothness in a nature way,and can be applied to general rotary cutters and complex surfaces.Numerical examples demonstrate that the third-order point contact approach can improve the machining strip width greatly as compared with the recently reported second-order one. | ZHU LiMin 1 ,DING Han 2 &XIONG YouLun 2 1State Key Laboratory of Mechanical System and Vibration,Shanghai Jiao Tong University,Shanghai 200240,China 2State Key Laboratory of Digital Manufacturing Equipment and Technology,Huazhong University of Science and Technology,Wuhan 430074, China | 2010 | Science China(Technological Sciences)2010，53，8： | 23 |
| 2 | Role of secondary aerosols in haze formation in summer in the Megacity Beijing显示文摘A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility < 10 km and RH(relative humidity) < 90%. Four haze episodes, which accounted for ~ 60% of the time during the whole campaign, were characterized by increases of SNA(sulfate, nitrate, and ammonium) and SOA(secondary organic aerosol) concentrations. The average values with standard deviation of SO2-+4, NO-3, NH4 and SOA were 49.8(± 31.6), 31.4(±22.3), 25.8(±16.6) and 8.9(±4.1) μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO2-4,NO-3, NH+4, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR(sulfur oxidation ratio) and NOR(nitrogen oxidation ratio) increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO2-4and NO2 to NO-3, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing. | Tingting Han Xingang Liu Yuanhang Zhang Yu Qu Limin Zeng Min Hu Tong Zhu | 2015 | Journal of Environmental Sciences2015，27，5： | 22 |
| 3 | Wholly smoothing cutter orientations for five-axis NC machining based on cutter contact point mesh显示文摘Cutting forces with respect to different cutter orientations are analyzed for five-axis NC machining of a ball-end cutter.A measure is then defined to quantify the effects of cutter orientation variation.According to the measure,a novel model and algorithm are proposed to wholly optimize cutter orientations based on a cutter contact(CC) point mesh.The method has two advantages.One is that the cutter orientation smoothnesses along the feed direction and pick-feed direction are both wholly optimized.The other is that only the accessibility cones of mesh points are required to compute and the computation efficiency is improved.These advantages are shown by simulating the machining efficiency,the stability of feed velocities and the smoothness of cutting force.A computational example and a cutting experiment are finally given to illustrate the validity of the proposed method. | BI QingZhen,WANG YuHan,ZHU LiMin & DING Han State Key Laboratory of Mechanical System and Vibration,School of Mechanical Engineering,Shanghai Jiaotong University,Shanghai 200240,China | 2010 | Science China(Technological Sciences)2010，53，5： | 12 |
| 4 | Tool path generation and simulation of dynamic cutting process for five-axis NC machining显示文摘Five-axis NC machining provides a valid and efficient way to manufacture the mechanical parts with complex shapes,which are widely used in aerospace,energy and national defense industries. Its technology innovations have attracted much attention in recent years. In this paper,the state-of-the-art techniques for five-axis machining process planning are summarized and the challenging problems are analyzed from the perspectives of tool path generation,integrated geometric/mechanistic simulation and machining stability analysis. The recent progresses in accessibility-based tool orientation optimization,cutter location (CL) planning for line contact and three-order point contact machining,shape control of cutter envelope surface and milling stability prediction are introduced in detail. Finally,the emerging trends and future challenges are briefly discussed. | DING Han BI QingZhen ZHU LiMin XIONG YouLun | 2010 | Chinese Science Bulletin2010，55，30： | 11 |
| 5 | Milling stability analysis using the spectral method显示文摘This paper focuses on the development of an efficient semi-analytical solution of chatter stability in milling based on the spectral method for integral equations. The time-periodic dynamics of the milling process taking the regenerative effect into account is formulated as a delayed differential equation with time-periodic coefficients,and then reformulated as a form of integral equation. On the basis of one tooth period being divided into a series of subintervals,the barycentric Lagrange interpolation polynomials are employed to approximate the state term and the delay term in the integral equation,respectively,while the Gaussian quadrature method is utilized to approximate the integral term. Thereafter,the Floquet transition matrix within the tooth period is constructed to predict the chatter stability according to Floquet theory. Experimental-validated one-degree-of-freedom and two-degree-of-freedom milling examples are used to verify the proposed algorithm,and compared with existing algorithms,it has the advantages of high rate of convergence and high computational efficiency. | DING Ye ZHU LiMin ZHANG XiaoJian DING Han | 2011 | Science China(Technological Sciences)2011，54，12： | 11 |
| 6 | Inhibition of growth and metastasis of triple-negative breast cancer targeted by Traditional Chinese Medicine Tubeimu in orthotopic mice models显示文摘Objective: Triple-negative breast cancer(TNBC) is highly invasive and metastatic, which is in urgent need of transformative therapeutics. Tubeimu(TBM), the rhizome of Bolbostemma paniculatum(Maxim.) Franquet, is one of the Chinese medicinal herbs used for breast diseases since the ancient times. The present study evaluated the efficacy, especially the anti-metastatic effects of the dichloromethane extract of Tubeimu(ETBM) on TNBC orthotopic mouse models and cell lines.Methods: We applied real-time imaging on florescent orthotopic TNBC mice model and tested cell migration and invasion abilities with MDA-MB-231 cell line. Digital gene expression sequencing was performed and Kyoto Encyclopedia of Genes and Genomes(KEGG) analysis applied to explore the pathways influenced by ETBM.Moreover, quantitative real-time polymerase chain reactions(q RT-PCR) and Western blot were delivered to confirm the gene expression changes.Results: ETBM exhibited noticeable control on tumor metastasis and growth of TNBC tumors with no obvious toxicity. In compliance with this, it also showed inhibition of cell migration and invasion in vitro. Its impact on the changed biological behavior in TNBC may be a result of decreased expression of integrin β1(ITGβ1), integrin β8(ITGβ8) and Rho GTPase activating protein 5(ARHGAP5), which disabled the focal adhesion pathway and caused change in cell morphology.Conclusions: This study reveals that ETBM has anti-metastatic effects on MDA-MB-231-GFP tumor and may lead to a new therapeutic agent for the integrative treatment of highly invasive TNBC. | Jingxiao Wang Xinjie Yang Haibo Han Limin Wang Weiqian Bao Shanshan Wang Robert M.Hoffman Meng Yang Hui Qi Chao An Kaiwen Hu | 2018 | Chinese Journal of Cancer Research2018，30，1： | 8 |
| 7 | A unified approach for least-squares surface fitting显示文摘This paper presents a novel approach for least-squares fitting of complex surface to measured 3D coordinate points by adjusting its location and/or shape. For a point expressed in the machine reference frame and a deformable smooth surface represented in its own model frame, a signed point-to-surface distance function is defined,and its increment with respect to the differential motion and differential deformation of the surface is derived. On this basis, localization, surface reconstruction and geometric variation characterization are formulated as a unified nonlinear least-squares problem defined on the product space SE(3)×m. By using Levenberg-Marquardt method, a sequential approximation surface fitting algorithm is developed. It has the advantages of implementational simplicity, computational efficiency and robustness. Applications confirm the validity of the proposed approach. | ZHU Limin DING Han | 2004 | Science China(Physics,Mechanics & Astronomy)2004，47，z1： | 7 |
| 8 | Jurassic Hornblende Gabbros in Dongga,Eastern Gangdese,Tibet:Partial Melting of Mantle Wedge and Implications for Crustal Growth显示文摘The Gangdese batholith, more than 2500 km in length, is composed mainly of JurassicMiocene igneous rocks. This batholith is one of the most important constituents of the Tibetan orogenesis and provides an ideal place for study of Neo-Tethyan ocean geodynamic evolution and plateau uplift. Recent studies on the Gangdese Jurassic felsic magmatism highlight its juvenile source. However, important aspects concerning the genesis of the juvenile magmatism and related deep geodynamic evolution are still unclear. Here, we report detailed petrological, geochronological, geochemical, whole-rock Sr-Nd isotopic, and in situ Sr-Hf isotopic data for a recently identified hornblende gabbro in the Dongga area, southern Lhasa sub-block. This hornblende gabbro is dominated by hornblende and plagioclase, dated at Early Jurassic(ca. 180–190 Ma), and characterized by a narrow compositional range in SiO_2(49.38wt%–52.27wt%), MgO(4.08wt%–7.00wt%), FeO(10.43wt%–11.77wt%), Na_2O(2.58wt%–3.51wt%), and K_2O(0.48wt%–1.53wt%). It has depleted isotopic signatures, with whole-rock(^(87)Sr/^(86)Sr)i ratios of 0.7033–0.7043, ε_(Nd)(t) values of +4.90 to +6.99, in situ plagioclase(^(87)Sr/^(86)Sr)i ratios of 0.7034–0.7042, and zircon ε_(Hf)(t) of +12.2 to +16.8. Our results integrated with published data suggest a model of Gangdese juvenile crustal growth by a subduction-related water-enriched mantle wedge. The hydrous partial melting of the lithosphere mantle was triggered by the dehydration of a Neo-Tethyan oceanic slab. This mafic magmatism emplaced in the middle-lower crust of intraoceanic arcs or active continental margins, leading to Jurassic juvenile crustal growth in southern Tibet. | XU Bo HOU Zengqian ZHENG Yuanchuan ZHOU Ye ZHOU Limin YANG Yu HAN Yanwei ZHEN Guo WU Changda | 2017 | Acta Geologica Sinica(English Edition)2017，91，2： | 7 |
| 9 | Transparent paper-based triboelectric nanogenerator as a page mark and anti-theft sensor显示文摘基于著名摩擦电效果和静电的正式就职效果,摩擦电 nanogenerator (TENG ) 被证明了是一条简单、合算的途径让自我动力的系统把周围的机械精力变换成电。我们报导由当摩擦电出现,电影和聚乙烯 terephthalate (宠物) 拍摄的铟听氧化物(ITO ) 组成的灵活、透明的基于纸的摩擦电 nanogenerator (PTENG ) ,它充当精力供应而且作为一个自我动力的活跃传感器不仅。当纸的表进入接触时,它能相对由垂直接触分离模式和侧面的滑动模式的联合的对方收获动能,弯曲或滑动。另外,我们也作为一个自我动力的反偷窃传感器把组织栅栏的 PTENG 集成到一本书。在处理期间,这本书分页的机械焦虑能有效地被变换成电的产量驾驶一台商业电子设备或触发警告 buzzer。而且,每页上的不同栅栏结构由相对对方滑动生产产量山峰的不同数字,它能精确地充当页的数字转了的一个页标记和记录。这个工作在自我动力的基于纸的设备向前是重要的步。 | Limin Zhang Fei Xue Weiming Du Changbao Han Chi Zhang Zhonglin Wang | 2014 | Nano Research2014，7，8： | 7 |
| 10 | Triboelectrification induced UV emission from plasmon discharge显示文摘紫外有的高精力的电磁的放射广泛地在工业生产和科学研究领域被使用。在这个工作,深紫外的轻排出物用 triboelectrification 被获得没有任何额外的电源供应的导致的血浆分泌物。由在聚合物和石英玻璃之间的机械磨擦,摩擦电费用引起一个变化电场,它可以带低压力气体(Ar-Hg ) 的血浆分泌物并且给出 253.7 nm 照耀。连续磨擦引起的紫外光能使三色的黄磷激动并且负担得起明亮白的轻排出物。一个紫外消毒实验证明 98% Escherichia coli 能被紫外照耀在 30 min 打死,它表明有好消毒效果的一台自我动力的消毒仪器被制作。这个工作提供一个新奇图案用低频率的机械磨擦制作一台自我动力的紫外轻射出设备并且认识到联合 triboelectrification 和血浆光,它可以进一步在特殊情形扩展紫外光的申请。 | Chang Bao Han Chi Zhang Jingjing Tian Xiaohui Li Limin Zhang Zhou Li Zhong Lin Wang | 2015 | Nano Research2015，8，1： | 5 |
| 11 | Ternary mesoporous cobalt-iron-nickel oxide efficiently catalyzing oxygen/hydrogen evolution reactions and overall water splitting显示文摘Among various efficient electrocatalysts for water splitting,CoFe and NiFe-based oxides/hydroxides are typically promising candidates thanks to their extraordinary activities towards oxygen evolution reaction (OER).However,the endeavor to advance their performance towards overall water splitting has been largely impeded by the limited activities for hydrogen evolution reaction (HER).Herein,we present a CoFeNi ternary metal-based oxide (CoFeNi-O) with impressive hierarchical bimodal channel nanostructures,which was synthesized via a facile one-step dealloying strategy.The oxide shows superior catalytic activities towards both HER and OER in alkaline solution due to the alloying effect and the intrinsic hierarchical porous structure.CoFeNi-O loaded on glass carbon electrodes only requires the overpotentials as low as 230 and 278 mV to achieve the OER current densities of 10 and 100 mA·cm-2,respectively.In particular,extremely low overpotentials of 200 and 57.9 mV are sufficient enough for Ni foam-supported CoFeNi-O to drive the current density of 10 mA·cm-2 towards OER and HER respectively,which is comparable with or even better than the already-developed state-of-the-art non-noble metal oxide based catalysts.Benefiting from the bifunctionalities of CoFeNi-O,an alkaline electrolyzer constructed by the Ni foam-supported CoFeNi-O electrodes as both the anode and the cathode can deliver a current density of 10 mA·cm-2 at a fairly low cell-voltage of 1.558 V.In view of its electrocatalytic merits together with the facile and cost-effective dealloying route,CoFeNi-O is envisioned as a promising catalyst for future production of sustainable energy resources. | Lulu Han Limin Guo Chaoqun Dong Chi Zhang Hui Gao Jiazheng Niu Zhangquan Peng Zhonghua Zhang | 2019 | Nano Research2019，12，9： | 5 |
| 12 | Constraint-induced movement therapy promotes brain functional reorganization in stroke patients with hemiplegia显示文摘Stroke patients with hemiplegia exhibit flexor spasms in the upper limb and extensor spasms in the lower limb, and their movement patterns vary greatly. Constraint-induced movement therapy is an upper limb rehabilitation technique used in stroke patients with hemiplegia; however, studies of lower extremity rehabilitation are scarce. In this study, stroke patients with lower limb hemiplegia underwent conventional Bobath therapy for 4 weeks as baseline treatment, followed by constraint-induced movement therapy for an additional 4 weeks. The 10-m maximum walking speed and Berg balance scale scores significantly improved following treatment, and lower extremity motor function also improved. The results of functional MRI showed that constraint-induced movement therapy alleviates the reduction in cerebral functional activation in patients, which indicates activation of functional brain regions and a significant increase in cerebral blood perfusion. These results demonstrate that constraint-induced movement therapy promotes brain functional reorganization in stroke patients with lower limb hemiplegia. | Wenqing Wang Aihui Wang Limin Yu Xuesong Han Guiyun Jiang Changshui Weng Hongwei Zhang Zhiqiang Zhou | 2012 | Neural Regeneration Research2012，7，32： | 4 |
| 13 | Response Sensitivity Analysis of the Dynamic Milling Process Based on the Numerical Integration Method显示文摘As one of the bases of gradient-based optimization algorithms, sensitivity analysis is usually required to calculate the derivatives of the system response with respect to the machining parameters. The most widely used approaches for sensitivity analysis are based on time-consuming numerical methods, such as finite difference methods. This paper presents a semi-analytical method for calculation of the sensitivity of the stability boundary in milling. After transforming the delay-differential equation with time-periodic coefficients governing the dynamic milling process into the integral form, the Floquet transition matrix is constructed by using the numerical integration method. Then, the analytical expressions of derivatives of the Floquet transition matrix with respect to the machining parameters are obtained. Thereafter, the classical analytical expression of the sensitivity of matrix eigenvalues is employed to calculate the sensitivity of the stability lobe diagram. The two-degree-of-freedom milling example illustrates the accuracy and efficiency of the proposed method. Compared with the existing methods, the unique merit of the proposed method is that it can be used for analytically computing the sensitivity of the stability boundary in milling, without employing any finite difference methods. Therefore, the high accuracy and high efficiency are both achieved. The proposed method can serve as an effective tool for machining parameter optimization and uncertainty analysis in high-speed milling. | DING Ye ZHU Limin ZHANG Xiaojian DING Han | 2012 | Chinese Journal of Mechanical Engineering2012，25，5： | 4 |
| 14 | A general, fast and robust B-spline fitting scheme for micro-line tool path under chord error constraint显示文摘The discontinuity of linear tool path(or G01 blocks) brings about unnecessary feedrate deceleration and fluctuation during machining. To improve the continuity, the linear tool path is usually smoothed by the local transition method or the global fitting method. For micro-line tool path, the transition method will significantly decrease the machining efficiency and introduce feedrate fluctuation. The global fitting method cannot be directly used in the NC interpolation because the indispensable chord error checking and iterative fitting processes are computation-intensive. This paper presents a general, fast and robust B-spline fitting scheme under chord error constraint for high speed interpolation of micro-line tool path. The proposed fitting method guarantees the chord error by utilizing the strong convex hull property of B-spline curves. The knot vector and control points are initially generated by a progressive iterative approximation method and locally refined to conform to the chord error constraint by using an analytical method. The analytical approximation and refining methods avoid solving a linear system of equations that is necessary in the standard B-spline fitting method. The feasibility and efficiency of the proposed scheme has been verified via simulations and experiments. Compared with the traditional fitting method, the proposed scheme can strictly constrain the chord error and can significantly decrease the computational load. Compared with the transition scheme, the proposed scheme can significantly increase the machining efficiency for the same micro-line tool path under the same chord error tolerance. | BI QingZhen HUANG Jie LU YaoAn ZHU LiMin DING Han | 2019 | Science China(Technological Sciences)2019，62，2： | 4 |
| 15 | A recombinant receptor-binding domain in trimeric form generates protective immunity against SARSCoV-2 infection in nonhuman primates显示文摘A safe and effective vaccine is critical to combat the COVID-19 pandemic.Here,we developed a trimeric SARS-CoV-2 receptor-binding domain(RBD)subunit vaccine candidate that simulates the natural structure of the spike(S)trimer glycoprotein.Immunization with the RBD trimer-induced robust humoral and cellular immune responses,and a high level of neutralizing antibodies was maintained for at least 4.5 months.Moreover,the antibodies that were produced in response to the vaccine effectively cross-neutralized the SARS-CoV-2501Y.V2 variant(B.1.351).Of note,when the vaccine-induced antibodies dropped to a sufficiently low level,only one boost quickly activated the anamnestic immune response,conferring full protection against a SARSCoV-2 challenge in rhesus macaques without typical histopathological changes in the lung tissues.These results demonstrated that the SARS-CoV-2 RBD trimer vaccine candidate is highly immunogenic and safe,providing long-lasting,broad,and significant immunity protection in nonhuman primates,thereby offering an optimal vaccination strategy against COVID-19. | Limin Yang Deyu Tian Jian-bao Han Wenhui Fan Yuan Zhang Yunlong Li Wenqiang Sun Yanqiu Wei Xiaodong Tian Dan-dan Yu Xiao-li Feng Gong Cheng Yuhai Bi Yong-tang Zheng Wenjun Liu | 2021 | The Innovation2021，2，3： | 3 |
| 16 | On time-domain methods for milling stability analysis显示文摘As a basic and advanced machining technique,the high-speed milling process plays an important role in realizing the goal of high performance manufacturing.From the viewpoint of machining dynamics,obtaining chatter-free machining parameters is a prerequisite to guaranteeing machining accuracy and improving machining efficiency.This paper gives an overview on recent progress in time domain semi-analytical methods for chatter stability analysis of milling processes.The state of art methods of milling stability prediction in milling processes and their applications are introduced in detail.The bottlenecks involved are analyzed,and potential solutions are discussed.Finally,a brief prospect on future works is presented. | DING Han DING Ye ZHU LiMin | 2012 | Chinese Science Bulletin2012，57，33： | 3 |
| 17 | Cross-coupled controller design for triaxial motion systems based on second-order contour error estimation显示文摘The cross-coupled control(CCC)is widely applied to reduce contour errors in contour-following applications.In such situation,the contour error estimation plays an important role.Traditionally,the linear or second-order estimation approach is adopted for biaxial motion systems,whereas only linear approach is available for triaxial systems.In this paper,the second-order contour error estimation,which was presented in our previous work,is utilized to determine the variable CCC gains for motion control systems with three axes.An integrated stable motion control strategy,which combines the feedforward,feedback and CCC controllers,is developed for multiaxis CNC systems.Experimental results on a triaxial platform indicate that the CCC scheme based on the second-order estimation,compared with that based on the linear one,significantly reduces the contour error even in the conditions of high tracking feedrate and small radius of curvature. | ZHAO Huan ZHU LiMin DING Han | 2015 | Science China(Technological Sciences)2015，58，7： | 3 |
| 18 | Peroxyacetyl nitrate observed in Beijing in August from 2005 to 2009显示文摘Measurements of peroxyacetyl nitrate(PAN) were made at a Beijing urban site each August from2005 to 2009. Over this 5-year period, the average PAN concentration for August in each year increased from 3(2005) to 11.7 μg/m3(2007); however, it decreased rapidly in 2008(4.1 μg/m3).Generally, the variation over the 5 years showed a rise in the first part of the study period,followed by a decline. We considered two categories of local and regional air masses in this study, which revealed that the PAN concentration in Beijing was affected mainly by southeastern air masses. The August PAN variation was influenced predominantly by local air masses in 2005,but by 2009 regional air masses had become more important. This study showed the level and variation of PAN in the month of August in 5 consecutive years for the first time, and proved that control measures are useful in decreasing photochemical pollution; hence, these measures are probably feasible for other megacities too. Furthermore, this method of analyzing regional and local impacts might be useful for other studies as well. | Tianyu Gao Li Han Bin Wang Guang Yang Zhenqiang Xu Limin Zeng Jianbo Zhang | 2014 | Journal of Environmental Sciences2014，26，10： | 3 |
| 19 | Non-dormant Axillary Bud 1 regulates axillary bud outgrowth in sorghum显示文摘Tillering contributes to grain yield and plant architecture and therefore is an agronomically important trait in sorghum(Sorghum bicolor).Here,we identified and functionally characterized a mutant of the Nondormant Axillary Bud 1(NAB1)gene from an ethyl methanesulfonate-mutagenized sorghum population.The nab1 mutants have increased tillering and reduced plant height.Map-based cloning revealed that NAB1encodes a carotenoid-cleavage dioxygenase 7(CCD7)orthologous to rice(Oryza sativa)HIGH-TILLERING DWARF1/DWARF17 and Arabidopsis thaliana MORE AXILLARY BRANCHING 3.NAB1 is primarily expressed in axillary nodes and tiller bases and NAB1 localizes to chloroplasts.The nab1 mutation causes outgrowth of basal axillary buds;removing these non-dormant basal axillary buds restored the wild-type phenotype.The tillering of nab1 plants was completely suppressed by exogenous application of the synthetic strigolactone analog GR24.Moreover,the nab1plants had no detectable strigolactones and displayed stronger polar auxin transport than wild-type plants.Finally,RNA-seq showed that the expression of genes involved in multiple processes,including auxin-related genes,was significantly altered in nab1.These results suggest that NAB1 functions in strigolactone biosynthesis and the regulation of shoot branching via an interaction with auxin transport. | Jun Chen Limin Zhang Mengjiao Zhu Lijie Han Ya Lv Yishan Liu Pan Li Haichun Jing Hongwei Cai | 2018 | Journal of Integrative Plant Biology2018，60，10： | 3 |
| 20 | Upregulation of SIRT1 by 17β-estradiol depends on ubiquitin-proteasome degradation of PPAR-γ mediated by NEDD4-1显示文摘17β-estradiol (E2) treatment of cells results in an upregulation of SIRT1 and a down-regulation of PPARγ. The decrease in PPARγ expression is mediated by increased degradation of PPARγ. Here we report that PPARγ is ubiquitinated by HECT E3 ubiquitin ligase NEDD4-1 and degraded, along with PPARγ, in response to E2 stimulation. The PPARγ interacts with ubiquitin ligase NEDD4-1 through a conserved PPXY-WW binding motif. The WW3 domain in NEDD4-1 is critical for binding to PPARΓ. NEDD4-1 overexpression leads to PPARγ ubiquitination and reduced expression of PPARγ. Conversely, knockdown of NEDD4-1 by specific siRNAs abolishes PPARΓ ubiquitination. These data indicate that NEDD4-1 is the E3 ubiquitin ligase responsible for PPARγ ubiquitination. Here, we show that NEDD4-1 delays cellular senescence by degrading PPARΓ expression. Taken together, our data show that E2 could upregulate SIRT1 expression via promoting the PPARΓ ubiquitination-proteasome degradation pathway to delay the process of cell senescence. | Limin Han Pan Wang Ganye Zhao Hui Wang Meng Wang Jun Chen Tanjun Tong | 2013 | Protein & Cell2013，4，4： | 3 |
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