Molecular basis for antifreeze activity difference of two insect antifreeze protein isoforms

The insect spruce budworm(Choristoneura fumiferana) produces antifreeze protein(AFP) to assist in the protection of the over-wintering larval stage and contains multiple isoforms. Structures for two isoforms,known as CfAFP-501 and CfAFP-337,show that both possess similar left-handed β-helical structure,although thermal hysteresis activity of the longer isoform CfAFP-501 is three times that of CfAFP-337. The markedly enhanced activity of CfAFP-501 is not proportional to,and cannot be simply accounted for,by the increased ice-binding site resulting from the two extra coils in CfAFP-501. In or-der to investigate the molecular basis for the activity difference and gain better understanding of AFPs in general,we have employed several different computational methods to systematically study the structural properties and ice interactions of the AFPs and their deletion models. In the context of intact AFPs,a majority of the coils in CfAFP-501 has better ice interaction and causes stronger ice lattice disruption than CfAFP-337,strongly suggesting a cooperative or synergistic effect among β-helical coils. The synergistic effect would play a critical role and make significant contributions to the anti-freeze activity β-helical antifreeze proteins. This is the first time that synergistic effect and its implica-tion for antifreeze activity are reported for β-helical antifreeze proteins.     

化学工程:从基础研究到工业应用

本文介绍了我国中长期发展规划中所制定的化学化工学科发展目标,综述了化学工程学科近十余年来在队伍建设、平台建设和国家级奖励等方面所取得的成果,列举了若干化学工程在传递与过程强化、化工分离过程、精细与药物化工、能源化工和材料化工领域从基础研究到工业化应用的例子和成果,展望了化学工程学科今后发展的方向及目标.     

Experimental simulation of the Unruh effect on an NMR quantum simulator

A triad mode resonance, or three-wave resonance, is typical of dynamical systems with quadratic nonlinearities. Suspended cables are found to be rich in triad mode resonant dynamics. In this paper, modulation equations for cable’s triad resonance are formulated by the multiple scale method. Dynamic conservative quantities, i.e., mode energy and Manley-Rowe relations, are then constructed. Equilibrium/dynamic solutions of the modulation equations are obtained, and full investigations into their stability and bifurcation characteristics are presented. Various bifurcation behaviors are detected in cable’s triad resonant responses, such as saddle-node, Hopf, pitchfork and period-doubling bifurcations. Nonlinear behaviors, like jump and saturation phenomena, are also found in cable’s responses. Based upon the bifurcation analysis, two interesting properties associated with activation of cable’s triad resonance are also proposed, i.e., energy barrier and directional dependence. The first gives the critical amplitude of high-frequency mode to activate cable’s triad resonance, and the second characterizes the degree of difficulty for activating cable’s triad resonance in two opposite directions, i.e., with positive or negative internal detuning parameter.     

中能Abrasion-Ablation模型的核内核子密度分布修正

将具体的核内核子(包括中子、质子)密度分布引入到中能Abrasion-Ablation模型中,用修正后的模型计算了30MeV/u ⁴⁰Ar+^natAg反应中的弹核碎裂过程.结果表明,在非常周边的碰撞中,修正后的模型计算的碎片截面与修正前的计算相比有明显的差别,反映了核密度边缘弥散的影响.与实验结果的比较验证了中能弹核碎裂碎片能量相对于束流能量的降低是由摩擦作用引起的.     

SDS-PAGE study on photooxidation damage of lysozyme induced by riboflavin

The photooxidation damage of lysozyme under 315-375 nm irradiation in the presence of riboflavin was studied by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).Indica- tions showed that the mechanisms and products of oxidative damage were relative to the concentra- tion of riboflavin,the time of irradiation and the ambience.The type I process was examined in a nitrogen saturated solution,whereas both type I and type II were observed in an aerobic atmosphere and type II was the dominant process.The study also suggested that antioxidants,such as melatonin, can reduce the damage of lysozyme effectively.     

Measurements on diproton emission from the break-up channels of ~(23)Al and ~(22)Mg

Two-proton relative momentum distributions from the break-up channels 23Al→p+p+21Na and 22Mg→p+p+20Ne at an energy of 60-70 A MeV have been measured together with two-proton opening angles at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The results demonstrate the existence of diproton emission component from single-step 2He for highly excited 23Al and 22Mg.     

Multiparty-controlled teleportation of an arbitrary GHZ-class state by using a d-dimensional (N+2)-particle nonmaximally entangled state as the quantum channel

We present a scheme for multiparty-controlled teleportation of an arbitrary high-dimensional GHZ-class state with a d-dimensional (N+2)-particle GHZ state following some ideas from the teleportation (Chinese Physics B, 2007, 16: 2867). This scheme has the advantage of transmitting much fewer particles for controlled teleportation of an arbitrary multiparticle GHZ-class state. Moreover,we discuss the application of this scheme by using a nonmaximally entangled state as its quantum channel.     

Geometric and topological rigidity for compact submanifolds of odd dimension

We investigate rigidity problems for odd-dimensional compact submanifolds.We show that if Mn(n 5)is an odd-dimensional compact submanifold with parallel mean curvature in Sn+p,and if RicM(n-2-1n)(1+H2)and Hδn,whereδn is an explicit positive constant depending only on n,then M is a totally umbilical sphere.Here H is the mean curvature of M.Moreover,we prove that if Mn(n 5)is an odd-dimensional compact submanifold in the space form Fn+p(c)with c 0,and if RicM(n-2-εn)(c+H2),whereεn is an explicit positive constant depending only on n,then M is homeomorphic to a sphere.     

The existence theorem of absolute equilibrium about games on connected graph with state payoff vecto

By introducing state payoff vector to every state node on the connected graph in this paper, dynamic game is researched on finite graphs. The concept of simple strategy about games on graph defined by Berge is introduced to prove the existence theorem of absolute equilibrium about games on the connected graph with state payoff vector. The complete algorithm and an example in the three-dimensional connected mesh-like graph are given in this paper.     

Constrains on f(T) gravity with the strong gravitational lensing data

Strong lensing is an effective way to probing the properties of dark energy.In this paper,we use the strong lensing data to constrain the f(T)theory,which is a new modified gravity to explain the present accelerating cosmic expansion without the need of dark energy.In our discussion,the CMB and BAO data are also added to constrain model parameters tightly and three different f(T)models are studied.We find that strong lensing has an important role on constraining f(T)models,and once the CMB+BAO data is added,a tighter constraint is obtained.However,the consistency of our result with what is obtained from SNIa+CMB+BAO is actually model-dependent.