ISSN:0031-9228    

DOI:10.1063/1.2809482

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809483

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Many biological functions—such as nerve impulses, muscle contraction, vision and even conception—have their basis in a sudden change in cell membrane permeability. Specific membrane proteins act as gates or agents of active transport, regulating the flow of molecules and ions between the cell and its environment. Members of one class of membrane proteins, the ion channels, open in response to electrical, chemical or mechanical stimuli to allow the spontaneous flow of ions down a concentration or potential gradient across the cell membrane. In 1976 Erwin Neher and Bert Sakmann reported using a tiny yet simple electrode, called a patch clamp electrode, pressed up against a frog muscle cell to record for the first time the opening and closing of a single ion channel1 in a biological membrane. For their invention, refinement and application of the patch clamp and of the electronics for recording the minute currents it samples, Neher and Sakmann, now at the Max Planck Institutes in Go¨ttingen and Heidelberg, respectively, have been awarded the 1991 Nobel Prize in Physiology or Medicine. In honoring the two, the Nobel Assembly at the Karolinska Institute cited “their discoveries concerning the function of single ion channels in cells.”

ISSN:0031-9228    

DOI:10.1063/1.2809484

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Nearly 90&percent; of the world's energy needs are today supplied by fossil fuels. Long‐term reliance on fossil‐fuel energy sources, however, is acknowledged to be a dangerous strategy—despite the large reserves of coal available in the US and elsewhere. Use of fossil fuels exacerbates pollution and acid rain and heightens the risk of global warming by addingCO2to the atmosphere. Society will be served best if energy production in the next century uses environmentally attractive methods that do not involve the combustion of fossil fuels. (See the article by John H. Gibbons and Peter D. Blair inPHYSICS TODAY, July 1991, page 22.) The long time required to develop and implement new large‐scale energy technologies—on the order of decades—underscores the urgency of the need to accelerate development of alternative energy sources.

ISSN:0031-9228    

DOI:10.1063/1.881337

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Tokamak experiments have made dramatic progress over the past two decades, and today plasma parameters are nearing the values needed for a fusion reactor. (See the article by J. Geoffrey Cordey, Robert J. Goldston and Ronald R. Parker on page 22.) In November 1991 the first deuterium‐tritium experiments in the Joint European Torus in Abingdon, England, generated a peak fusion power of almost 2 megawatts and a total energy release of 2 megajoules in a 2‐second pulse. Concomitant progress has been made in understanding the basic physics of tokamak plasmas; this was made possible by major developments in plasma science, nonlinear theory, plasma diagnostic capabilities and supercomputer calculations.

ISSN:0031-9228    

DOI:10.1063/1.881338

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Having been to Constantinople, Athens, Smyrna and Algiers, and several times to America, I've been urged repeatedly to publish accounts of some of my travels. But it all seemed to me too insignificant. My recent trip to California, however, was something quite exquisite. So I will venture a little chat about it.

ISSN:0031-9228    

DOI:10.1063/1.881339

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809485

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809486

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809487

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809488

出版商:AIP    

年代:1992

数据来源: AIP