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Short Summary (short + summary)
Selected AbstractsWanted: geophysics for teachersASTRONOMY & GEOPHYSICS, Issue 4 2008Article first published online: 10 JUL 200 The Institute of Physics is seeking short summaries of geophysics topics to support school teachers, in a move aimed at boosting the teaching and awareness of geophysics in schools. [source] Contributions of Yuri L. Klimontovich to the kinetic theory of nonideal plasmasCONTRIBUTIONS TO PLASMA PHYSICS, Issue 5-6 2003M. Bonitz Abstract We give a short summary of live and work of Yuri L. Klimontovich (1924,2002), in particular we discuss his work on nonideal plasma physics. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Etiology of cicatricial alopecias: a basic science point of viewDERMATOLOGIC THERAPY, Issue 4 2008Kevin J. McElwee ABSTRACT: This article presents a short summary of our current knowledge of cicatricial alopecia disease pathogenesis and the hypothetical disease mechanisms that may be involved in scarring alopecia development. Several forms of scarring alopecia likely involve targeted cytotoxic action against hair follicle cells mediated by a folliculocentric inflammation. However, the specific nature of the inflammatory interference in hair follicle growth is open to question. A popular hypothesis of lymphocyte-mediated scarring alopecia development involves autoimmune targeting of hair follicle,specific self-antigens, although there is no direct evidence in support of such a view. Alternative hypotheses focus on defects in sebaceous gland function, destruction of hair follicle stem cells, and interference in the communication between hair follicle mesenchyme and epithelium. Many questions arise from these hypotheses, and addressing them with a systematic research approach may enable significant advances in understanding cicatricial alopecia etiology. [source] Active cooling in traumatic brain-injured patients: a questionable therapy?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2009P.-O. GRÄNDE Hypothermia is shown to be beneficial for the outcome after a transient global brain ischaemia through its neuroprotective effect. Whether this is also the case after focal ischaemia, such as following a severe traumatic brain injury (TBI), has been investigated in numerous studies, some of which have shown a tendency towards an improved outcome, whereas others have not been able to demonstrate any beneficial effect. A Cochrane report concluded that the majority of the trials that have already been published have been of low quality, with unclear allocation concealment. If only high-quality trials are considered, TBI patients treated with active cooling were more likely to die, a conclusion supported by a recent high-quality Canadian trial on children. Still, there is a belief that a modified protocol with a shorter time from the accident to the start of active cooling, longer cooling and rewarming time and better control of blood pressure and intracranial pressure would be beneficial for TBI patients. This belief has led to the instigation of new trials in adults and in children, including these types of protocol adjustments. The present review provides a short summary of our present knowledge of the use of active cooling in TBI patients, and presents some tentative explanations as to why active cooling has not been shown to be effective for outcome after TBI. We focus particularly on the compromised circulation of the penumbra zone, which may be further reduced by the stress caused by the difference in thermostat and body temperature and by the hypothermia-induced more frequent use of vasoconstrictors, and by the increased risk of contusional bleedings under hypothermia. We suggest that high fever should be reduced pharmacologically. [source] Implications of bulk motion for diffusion-weighted imaging experiments: Effects, mechanisms, and solutionsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2001David G. Norris PhD Abstract This review article describes the effect of bulk motion on diffusion-weighted imaging experiments, and examines methods for correcting the resulting artifacts. The emphasis throughout the article is on two-dimensional imaging of the brain. The effects of translational and rotational motion on the MR signal are described, and the literature concerning pulsatile brain motion is examined. Methods for ameliorating motion effects are divided into three generic categories. The first is methods that should be intrinsically insensitive to macroscopic motion. These include motion-compensated diffusion-weighting schemes, single-shot EPI, projection reconstruction, and line scanning. Of these, only single-shot EPI and projection reconstruction methods can obtain high-quality images without compromising on sensitivity. The second category of methods is those that can be made insensitive to bulk motion. The methods examined here are FLASH and RARE. It is shown that for both sequences motion insensitivity is in general attained only at the cost of a 50% reduction in sensitivity. The final set of methods examined are those that correct for motion, primarily navigator echoes. The properties and limitations of the navigator echo approach are presented, as are those of methods which attempt to correct the acquired data by minimizing image artifacts. The review concludes with a short summary in which the current status of diffusion imaging in the presence of bulk motion is examined. J. Magn. Reson. Imaging 2001;13:486,495. © 2001 Wiley-Liss, Inc. [source] Past, present and future of atomic force microscopy in life sciences and medicineJOURNAL OF MOLECULAR RECOGNITION, Issue 6 2007Pierre Parot Abstract To introduce this special issue of the Journal of Molecular Recognition dedicated to the applications of atomic force microscopy (AFM) in life sciences, this paper presents a short summary of the history of AFM in biology. Based on contributions from the first international conference of AFM in biological sciences and medicine (AFM BioMed Barcelona, 19,21 April 2007), we present and discuss recent progress made using AFM for studying cells and cellular interactions, probing single molecules, imaging biosurfaces at high resolution and investigating model membranes and their interactions. Future prospects in these different fields are also highlighted. Copyright © 2007 John Wiley & Sons, Ltd. [source] Solid-State Ionics: Roots, Status, and Future ProspectsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2002Philippe Knauth This review represents the authors' view of the evolution of solid-state ionics over approximately the past 100 years. A brief history, introducing milestones of the development of this discipline, is followed by a short summary of the theory of ionic conduction in the bulk and the more recently developed theory of ionic conduction at interfaces. The central part of the article gives examples of ionic-conducting materials systems with structures ranging from one- to three-dimensional disorder. Important experimental techniques for analyzing ionic conduction, including alternating-current impedance spectroscopy, direct-current coulometry, and direct-current current-voltage measurements with blocking electrodes, are also summarized. The main technological applications, that is, batteries, solid-oxide fuel cells, electrochemical sensors, electrochromic windows, and oxygen-separation membranes, are reviewed. Finally, new concepts in solid-state ionics are presented, including the investigation of new materials (such as nanostructured phases), the study of boundaries (for example, using microelectrodes), the development of computational techniques, and the connections with other classes of materials (notably magnetic and semiconducting materials). [source] Primary Photophysical Processes in Photosystem II: Bridging the Gap between Crystal Structure and Optical SpectraCHEMPHYSCHEM, Issue 6 2010Thomas Renger Prof. Dr. Abstract This Minireview summarizes our current knowledge of the optical properties of photosystem II (PS-II) and how these properties are related to the photosynthetic function, that is, excitation energy transfer from the antenna complexes to the reaction center (RC) and the subsequent transmembrane charge separation in the latter. Interpretation of the optical spectra of PS-II is much more difficult than for the RC of purple bacteria, due to the "spectral congestion" problem, namely, the strong spectral overlap of optical bands in PS-II. Recent developments in deciphering the optical properties of the pigments in PS-II, the identification of functional states, and the kinetic details of the primary excitation energy and charge-transfer reactions are summarized. The spectroscopic term P680 that is generally used in the literature no longer indicates the same entity in its cationic and singlet excited form but different subsets of the six innermost pigments of the RC. The accessory chlorophyll ChlD1 forms a sink for singlet excitation and triplet energy and most likely represents the primary electron donor in PS-II. In this respect, a special chlorophyll monomer in PS-II plays the role of the special pair in purple bacteria. Evidence that exciton transfer between the core antenna complexes CP43 and CP47 and the RC is the bottleneck for the overall photochemical trapping of excitation energy in PS-II is discussed. A short summary is provided of PS-II of Acaryochloris marina, which mainly contains chlorophyll d instead of the usual chlorophyll a. This system does not suffer from the spectral congestion problem and, therefore, represents an interesting model system. The final part of this Minireview provides a discussion of challenging problems to be solved in the future. [source] | ||||||||||||||||