Rab protein evolution and the history of the eukaryotic endomembrane system

Spectacular increases in the quantity of sequence data genome have facilitated major advances in eukaryotic comparative genomics. By exploiting homology with classical model organisms, this makes possible predictions of pathways and cellular functions currently impossible to address in intractable organisms. Echoing realization that core metabolic processes were established very early following evolution of life on earth, it is now emerging that many eukaryotic cellular features, including the endomembrane system, are ancient and organized around near-universal principles. Rab proteins are key mediators of vesicle transport and specificity, and via the presence of multiple paralogues, alterations in interaction specificity and modification of pathways, contribute greatly to the evolution of complexity of membrane transport. Understanding system-level contributions of Rab proteins to evolutionary history provides insight into the multiple processes sculpting cellular transport pathways and the exciting challenges that we face in delving further into the origins of membrane trafficking specificity.     

Hartree and Thomas: the forefathers of density functional theory

Douglas Hartree and Hilleth Thomas were graduate students together at Cambridge University in the mid-1920s. Each developed an important approximation method to calculate the electronic structure of atoms. Each went on to make significant contributions to numerical analysis and to the development of scientific computing. Their early efforts were fused in the mid-1960s with the development of an approach to the many-particle problem in quantum mechanics called density functional theory. This paper discusses the experiences which led Hartree and Thomas to their approximations, outlines the similarities in their subsequent careers, and highlights the essential role their work played in the foundational papers of modern density functional theory.     

拉格朗日流体动力学

本书是《剑桥力学专著》系列丛书之一。如今，对深海中声音跟踪漂浮物和卫星导航的地面移动物体观察系统的迫切需要，使人们对拉格朗日流体动力学重新产生兴趣。本书首先介绍拉格朗日框架下的经典解和新的精确解，接着讨论所得到的一般运动方程的可解性，最后论述湍流扩散和散射的统一考虑，并应用到海洋中的浮游生物片。     

White-breasted Nuthatch ( Sitta carolinensis ) fecal sac dispersal in northwestern Nevada

Field research on the dispersal of fecal sacs by parent White-breasted Nuthatches ( Sitta carolinensis ) was conducted on the eastern slopes of the Sierra Nevada in northwestern Nevada. Fecal sacs were dropped 6-60 m from the nest, with 56% of the total droppings ( n = 66) being dropped 48-60 m away. Ninety-five percent of sac dispersal was in the southwest quadrant, the food-foraging site. Also, 75% of non-sac flights during the nestling phase were in the direction of the foraging area, a dead, mature Jeffrey pine ( Pinus jeffreyi ). Fecal sac dispersal by parent Whitebreasted Nuthatches may reduce or eliminate detection of nestlings by avian predators.     

Anodic dissolution of metals in ionic liquids

The anodic dissolution of metals is an important topic for battery design, material finishing and metal digestion. Ionic liquids are being used in all of these areas but the research on the anodic dissolution is relatively few in these media. This study investigates the behaviour of 9 metals in an ionic liquid [C4mim][Cl] and a deep eutectic solvent, Ethaline, which is a 1:2 mol ratio mixture of choline chloride and ethylene glycol. It is shown that for the majority of metals studied a quasi-passivation of the metal surface occurs, primarily due to the formation of insoluble films on the electrode surface. The behaviour of most metals is different in [C4mim][Cl] to that in Ethaline due in part to the differences in viscosity. The formation of passivating salt films can be decreased with stirring or by increasing the electrolyte temperature, thereby increasing ligand transport to the electrode surface.     

Recent advances in Cys-loop receptor structure and function

Throughout the nervous system, moment-to-moment communication relies on postsynaptic receptors to detect neurotransmitters and change the membrane potential. For the Cys-loop superfamily of receptors, recent structural data have catalysed a leap in our understanding of the three steps of chemical-to-electrical transduction: neurotransmitter binding, communication between the binding site and the barrier to ions, and opening and closing of the barrier. The emerging insights might be expected to explain how mutations of receptors cause neurological disease, but the opposite is generally true. Namely, analyses of disease-causing mutations have clarified receptor structure-function relationships as well as mechanisms governing the postsynaptic response.