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| 1 | Plasmonic enhancement of upconversion emission in Ag@NaYF4:Er^3+/Yb^3+phosphor显示文摘In this article upconversion luminescence of silver nanoparticles(AgNPs) coated NaYF_4:Er^(3+)/Yb^(3+)phosphor nano-particles was investigated.The prepared samples were characterized through various techniques.The surface plasmon band is observed for prepared AgNPs by analyzing UV-vis measurements and is used to enhance the upconversion emission.From the upconversion measurement the emission bands are observed at 522,546,and 656 nm corresponding to the ~2 H_(11/2)→ 4~1_(15/2),~4 S_(3/2)→~4 I_(15/2)and ~4 F_(9/2)→~4 I_(15/2) levels,respectively.The upconversion emission intensity of the above bands is found to enhance for sample containing 1 mmol AgNPs.Decay time of ~4 S_(3/2) and 4~F_(9/2) levels is found to decrease on coating of AgNPs and hence intensity enhancement is assumed due to the surface plasmon resonance(SPR) effect. | S.K.Maurya S.R Tiwari A.Kumar K.Kumar | 2018 | Journal of Rare Earths2018，36，9： | 3 |
| 2 | Mechanics of granular column collapse in fluid at varying slope angles显示文摘This paper investigates the effect of initial volume fraction on the runout characteristics of collapse of granular columns on slopes in fluid. 2-D sub-grain scale numerical simulations are performed to understand the flow dynamics of granular collapse in fluid. The discrete element method(DEM) technique is coupled with the lattice Boltzmann method(LBM), for fluid-grain interactions, to understand the evolution of submerged granular flows. The fluid phase is simulated using multiple-relaxation-time LBM(LBM-MRT) for numerical stability. In order to simulate interconnected pore space in 2-D, a reduction in the radius of the grains(hydrodynamic radius) is assumed during LBM computations. The collapse of granular column in fluid is compared with the dry cases to understand the effect of fluid on the runout behaviour. A parametric analysis is performed to assess the influence of the granular characteristics(initial packing) on the evolution of flow and run-out distances for slope angles of 0 °, 2.5°, 5 ° and 7.5 °. The granular flow dynamics is investigated by analysing the effect of hydroplaning, water entrainment and viscous drag on the granular mass. The mechanism of energy dissipation, shape of the flow front, water entrainment and evolution of packing density is used to explain the difference in the flow characteristics of loose and dense granular column collapse in fluid. | K.Kumar J.-Y.Delenne K.Soga | 2017 | Journal of Hydrodynamics2017，29，4： | 2 |
| 3 | Cell cycle regulation and hematologic malignancies显示文摘A complex network precisely regulates the cell cycle through the G1,S,G2,and M phases and is the basis for cell division under physiological and pathological conditions.On the one hand,the transition from one phase to another as well as the progression within each phase is driven by the specific cyclin-dependent kinases(CDKs;e.g.,CDK1,CDK2,CDK4,CDK6,and CDK7),together with their exclusive partner cyclins(e.g.,cyclin A1,B1,D1–3,and E1).On the other hand,these phases are negatively regulated by endogenous CDK inhibitors such as p16^(ink4a),p18^(ink4c),p19^(ink4d),p21^(cip1),and p27^(kip1).In addition,several checkpoints control the commitment of cells to replicate DNA and undergo mitosis,thereby avoiding the passage of genomic errors to daughter cells.CDKs are often constitutively activated in cancer,which is characterized by the uncontrolled proliferation of transformed cells,due to genetic and epigenetic abnormalities in the genes involved in the cell cycle.Moreover,several oncogenes and defective tumor suppressors promote malignant changes by stimulating cell cycle entry and progression or disrupting DNA damage responses,including the cell cycle checkpoints,DNA repair mechanisms,and apoptosis.Thus,genes or proteins related to cell cycle regulation remain the main targets of interest in the treatment of various cancer types,including hematologic malignancies.In this context,advances in the understanding of the cell cycle regulatory machinery provide a basis for the development of novel therapeutic approaches.The present article summarizes the pathways as well as their genetic and epigenetic alterations that regulate the cell cycle;moreover,it discusses the various approved or potential therapeutic targets associated with the cell cycle,focusing on hematologic malignancies. | Yun Dai Fengyan Jin Wei Wu Shaji K.Kumar | 2019 | Blood Science2019，1，1： | 0 |
| 4 | Ligament reconstruction with tendon interposition arthroplasty for first carpometacarpal joint osteoarthritis显示文摘 | Yang Yong Huey Y.Tien Kannan K.Kumar Chen Shanlin Li Zhongzhe Tian Wen Tian Guanglei | 2014 | Chinese Medical Journal2014，，22： | 0 |
| 5 | Reentrant equilibrium disordering in nanoparticle-polymer mixtures显示文摘A large body of experimental work has established that athermal colloid/polymer mixtures undergo a sequence of transitions from a disordered fluid state to a colloidal crystal to a second disordered phase with increasing polymer concentration.These transitions are driven by polymer-mediated interparticle attraction,which is a function of both the polymer density and size.It has been posited that the disordered state at high polymer density is a consequence of strong interparticle attractions that kinetically inhibit the formation of the colloidal crystal,i.e.,the formation of a non-equilibrium gel phase interferes with crystallization.Here we use molecular dynamics simulations and density functional theory on polymers and nanoparticles(NPs)of comparable size and show that the crystal-disordered phase coexistence at high polymer density for sufficiently long chains corresponds to an equilibrium thermodynamic phase transition.While the crystal is,indeed,stabilized at intermediate polymer density by polymer-induced intercolloid attractions,it is destabilized at higher densities because long chains lose significant configurational entropy when they are forced to occupy all of the crystal voids.Our results are in quantitative agreement with existing experimental data and show that,at least in the nanoparticle limit of sufficiently small colloidal particles,the crystal phase only has a modest range of thermodynamic stability. | Dong Meng Sanat K.Kumar Gary S.Grest Nathan A.Mahynski Athanassios Z.Panagiotopoulos | 2017 | npj Computational Materials2017，，1： | 0 |
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