Atomic structure of a voltage-dependent K+ channel in a lipid membrane-like environment

Voltage-dependent K+ (Kv) channels repolarize the action potential in neurons and muscle. This type of channel is gated directly by membrane voltage through protein domains known as voltage sensors, which are molecular voltmeters that read the membrane voltage and regulate the pore. Here we describe the structure of a chimaeric voltage-dependent K+ channel, which we call the 'paddle-chimaera channel', in which the voltage-sensor paddle has been transferred from Kv2.1 to Kv1.2. Crystallized in complex with lipids, the complete structure at 2.4 ?ngstr?m resolution reveals the pore and voltage sensors embedded in a membrane-like arrangement of lipid molecules. The detailed structure, which can be compared directly to a large body of functional data, explains charge stabilization within the membrane and suggests a mechanism for voltage-sensor movements and pore gating.     

Science,self improvement and the first industrial revolution

This study considers Newton's views on space and time with respect to some important ontologies of substance in his period. Specifically, it deals in a philosophico-historical manner with his conception of substance, attribute, existence, to actuality and necessity. I show how Newton links these “features” of things to his conception of God's existence with respect of infinite space and time. Moreover, I argue that his ontology of space and time cannot be understood without fully appreciating how it relates to the nature of Divine existence. In order to establish this, the ontology embodied in Newton's theory of predication is analysed, and shown to be different from the presuppositions of the ontological argument. From the historical point of view Gassendi's influence is stressed, via the mediation of Walter Charleton. Furthermore, Newton's thought on these matters is contrasted with Descartes's and Spinoza's. In point of fact, in his earliest notebook Newton recorded observations on Descartes's version of the ontological argument. Soon, however, he was to oppose the Cartesian conception of the actuality of Divine existence by means of arguments similar to those of Gassendi. Lastly, I suggest that the nature and extent of Henry More's influence on Newton's conception of how God relates to absolute space and time bears further examination.     

Francis Hauksbee's theory of electricity

Conclusion Historians of science have usually assumed that the science of electricity developed in the period prior to Franklin, or at least prior to Nollet, in what amounted to a theoretical vacuum. It has been my aim in this paper to demonstrate the falsity of that assumption. I have shown, I hope, that Hauksbee's important researches were guided throughout by strong theoretical considerations, and I have indicated that Dufay's even more important studies were guided by exactly the same considerations. Nor was their theory in any sense a stagnant one. As it was developed by Hauksbee, it could give a fairly adequate explanation of almost all the known electrical phenomena; it even enabled him to predict the outcome of experiments such as the one involving the rubbing of a globe while it was positioned near a second, exhausted, globe. With the discovery of so many new phenomena in the 1730's, the theory turned out to be no longer adequate, but it is not at all surprising that it was a few years before the full extent of its inadequacies was appreciated, nor is it surprising that a strong continuity is evident between it and the theory which eventually replaced it. In the meantime, the theory continued to serve a useful function by suggesting new lines of research to its adherents. The theory functioned, then, in the same way as any other scientific theory, and it deserves a more serious treatment than it has usually received. This paper, I hope, can serve as a beginning.