检索结果-南通市图书馆

Positron emission particle tracking——Application and labelling techniques

在线全文

学校读者我要写书评

暂无评论

Particuology 2008年第1期6卷 16-23页

作者： David j. parker School of Physics and Astronomy the University of Birmingham Edgbaston Birmingham B15 2TT UK

The positron emission particle tracking （PEPT） technique has been widely used in science and engineering to obtain detailed information on the motion and flow fields of fluids or granular materials in multiphase systems, for example, fluids in rock cracks, chemical reactors and food processors; dynamic behaviour of granular materials in chemical reactors, granulators, mixers, dryers, rotating kilns and ball mills. The information obtained by the PEPT technique can be used to optimise the design, operational conditions for a wide range of industrial process systems, and to evaluate modelling work. The technique is based on tracking radioactively labelled particles （up to three particles） by detecting the pairs of backto-back 511 keV γ-rays arising from annihilation of emitted positrons. It therefore involves a positron camera, location algorithms for calculating the tracer location and speed, and tracer labelling techniques. This paper will review the particle tracking technique from tracking algorithm, tracer labelling to their application.

关键词： PEPT Tracer Algorithm Tracking

The ethical cost of doing nothing

在线全文

学校读者我要写书评

暂无评论

National Science Review 2020年第7期7卷 1260-1262页

作者： Andrew j.parker University of Oxford Department of PhysiologyAnatomy and Genetics

Concern has been raised about the ethics and risks of performing genetic interventions in macaque monkeys to study models of human neuropsychiatric conditions. Here I point out that,when the outcome of some situations is truly uncertain, human decision makers tend to evaluate these situations inconsistently. The consequences of this inconsistency are sometimes profound, as they lead policy makers and reviewers to ignore or discount the ethical costs of doing nothing. I conclude that there are fundamental problems with the ‘precautionary

关键词：

Contribution of national bioassessment approaches for assessing ecological water security： an AUSRIVAS case study

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2013年第5期7卷 669-687页

作者： Susan j. nichols Fiona j. DYER Institute for Applied Ecology and MDBfutures CRN University of Canberra Canberra ACT 2601 Australia

River managers in Australia are managing in the face of extremes to provide security of water supply for people, production and the environment. Balancing the water requirements of people, environments and econo- mies requires that water security is viewed holistically, not just in terms of the water available for human consump- tion. Common definitions of water security focus on the needs of both humans and ecosystems for purposes such as drinking, agriculture and industrial use, and to maintain ecological values. Information about achieving water security for the environment or ecological purposes can be a challenge to interpret because the watering require- ments of key ecological processes or assets are not well understood, and the links between ecological and human values are often not obvious to water users. Yet the concepts surrounding river health are inherently linked to holistic concepts of water security. The measurement of aquatic biota provides a valuable tool for managers to understand progress toward achieving ecological water security objectives. This paper provides a comprehensive review of the reference condition approach to river health assessment, using the development of the Australian River Assessment System （AUSRIVAS） as a case study. We make the link between the biological assessment of river health and assessment of ecological water security, and suggest that such an approach provides a way of reporting that is relevant to the contribution made by ecosystems to water security. The reference condition approach, which is the condition representative of minimally disturbed sites organized by selected physical, chemical, and biological characteristics, is most important for assessing ecological water security objectives.

关键词： ecological water security biological assessment river health

在线全文

学校读者我要写书评

暂无评论

镜片护理液的选择

养生大世界（B版） 2009年第12期 21-25页

作者： jason j.nichols 俄亥俄州立大学视光学院

角膜接触镜护理液最重要的功能是对镜片进行清洁和消毒，以及潜在的提高镜片配戴的舒适度。泪液中含有大量的蛋白和脂质，这些物质经常沉积在镜片上。在镜片配戴之后通过清洁去除镜片的沉积物的量随着镜片材料和所使用的角膜接触镜护理... 详细信息

角膜接触镜护理液最重要的功能是对镜片进行清洁和消毒，以及潜在的提高镜片配戴的舒适度。泪液中含有大量的蛋白和脂质，这些物质经常沉积在镜片上。在镜片配戴之后通过清洁去除镜片的沉积物的量随着镜片材料和所使用的角膜接触镜护理液的不同而不同。这篇文章回顾了不同的角膜接触镜护理液对泪液和镜片自身的影响，同时还回顾了多功能护理液和过氧化氢护理液对镜片清洁和消毒的效能，阐述了护理液过敏反应和其他与角膜接触镜相关的非感染性的并发症。（AdvStudOphthalmol．2008；5（3）：76—78）。角膜接触镜护理液最主要的功能是清洁镜片，去除镜片上沉积的来自泪液中的蛋白和脂质；对镜片进行消毒以及尽可能提高角膜接触配戴的舒适度。以上的3项功能互相作用，因为干净的镜片配戴起来更加舒适，同时被微生物污染的可能性更低。

关键词：多功能护理液镜片材料角膜接触镜微生物污染舒适度沉积物过氧化氢非感染性

Neuromodulator interactions and spinal cord injury in lamprey

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2018年第4期13卷 643-644页

作者： David parker Thomas j.McClelland Department of Physiology Neuroscience and DevelopmentUniversity of Cambridge

Neuromodulation is mediated by neurotransmitters that typically act on G-protein-coupled *** can confer behavioural flexibility by modifying the functional properties of anatomically hard-wired neural *** neuromodulators generally have divergent cellular and synaptic effects（Harris-Warrick and johnson,2010）,and different modulators,

关键词： Figure Neuromodulator interactions and spinal cord injury in lamprey

Positron imaging systems for studying particulate, granular and multiphase flows

在线全文

学校读者我要写书评

暂无评论

Particuology 2012年第2期10卷 146-153页

作者： Thomas W.Leadbeater David j.parker joseph Gargiuli Positron Imaging Centre University of BirminghamEdgbastonBirmingham B152TTUKa

The University of Birmingham has pioneered and adapted the use of the medical imaging technique known as positron emission tomography （PET） to the study of particulate, granular and multiphase flows in industrial and physical processes, This paper provides a review of the PET and complimentary positron emission particle tracking （PEPT） techniques and details their application to the study of particulate sys- tems, The current state of the art, recent developments and example results from many of the applications to which these techniques have been applied are highlighted.

关键词： Positron emission particle tracking (PEPT)Particle dynamicsMulti-phase flow measurement

An approach to viscoelastic c haracterization of dispersive media by inversion of a general wave propagation model

在线全文

学校读者我要写书评

暂无评论

journal of Innovative Optical Health Sciences 2017年第6期10卷 73-88页

作者： Fernando Zvietcovich jannick P.Rolland Kevin j.parker Department of Electrical and Computer Engineering University of Rochester Rochester New York 14627USA The Institute of Optics University of Rochester Rochester New York 14627USA

In the characterization of elastic properties of tissue using dynarmic optical coherence elasto-graphy,shear/surface waves are propagated and tracked in order to estimate speed and Y oung's ***,for dispersive tssues,the displacement pulse is highly damped and distorted during propagation,diminishing the ffectiveness of peak tracking approaches,and leading to biased cstimates of wave ***,plane wave propagation is sometimes assumed,which contributes to estimation ***,we invert a wave propagation model that incorpo-rates propagation,decay,and distortion of pulses in a dispersive media in order to accurately estimate its elastic and viscous *** model uses a general first-order approximation of dispersion,avoiding the use of any particular rheological model of *** are conducted in elastic and viscoelastic tissue mimicking phantoms by producing a Gaussian push using acoustic radiation force excitation and measuring the wave propagation using a Fourier domain optical coherence tomography *** confirmed the ffectiveness of the inversion method in est imat ing viscoelastic parameters in both the viscoelastic and elastic phantoms when compared to mechanical ***,the viscoelastic characterization of a fresh porcine comea was *** results validate this approach when compared to other methods.

关键词： Elastography viscoelasticity cylindrical waves optical coherence tomography shear waves surface acoustic waves viscoelastic pha ntoms

A collaboration into research on nanoparticles (ACORN)

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2009年第2期7卷 93-105页

作者： David G. parker Chemistry Innovation The HeathRuncorn WA7 4QXUnited Kingdom

This paper describes the operation and outcome of one of the United Kingdom＇s largest multi-partner research activities in nanoparticles. The research covers the discovery and development of organic and inorganic crystals/nanoparticles, nanoparticle properties towards specific product applications. The research also encompassed bespoke measurement technology for nanoparticles and structure interactions. Significant research outcomes are summarised. The paper illustrates the advantages from industrially motivated research and value of collective action between a broad group of researchers in a nation.

关键词： Nanoparticles Nanoparticle manufacture Nanocrystals Nanoassembly structure Modelling

Smelling fit： scent marking exposes parasitic infection status in the banded mongoose

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2017年第3期63卷 237-247页

作者： jessica MITCHELL Michael A. CANT Emma I.K. VITIKAINEN Hazel j. nichols School of Natural Sciences and Psychology Liverpool John Moores University Liverpool L3 AF UK Centrefor Ecology and Conservation University of Exeter Penryn Campus TRIO 9FE UK

Preference for uninfected mates is presumed beneficial as it minimizes one＇s risk of contracting an infection and infecting one＇s offspring. In avian systems, visual ornaments are often used to indi- cate parasite burdens and facilitate mate choice. However, in mammals, olfactory cues have been proposed to act as a mechanism allowing potential mates to be discriminated by infection status. The effect of infection upon mammalian mate choice is mainly studied in captive rodents where ex- perimental trials support preference for the odors of uninfected mates and some data suggest scent marking is reduced in individuals with high infection burdens. Nevertheless, whether such effects occur in nonmodel and wild systems remains poorly understood. Here, we investigate the interplay between parasite load （estimated using fecal egg counts） and scent marking behavior in a wild population of banded mongooses Mungos mungo. Focusing on a costly protozoan parasite of the genus Isospora and the nematode worm Toxocara, we first show that banded mongooses that engage in frequent, intensive scent marking have lower Isospora loads, suggesting marking behavior may be an indicator trait regarding infection status. We then use odor presentations to demonstrate that banded mongooses mark less in response to odors of opposite sexed individuals with high Isospora and Toxocara loads. As both of these parasites are known to have detrimental effects upon the health of preweaned young in other species, they would appear key targets to avoid during mate choice. Results provide support for scent as an important ornament and mechanism for advertising parasitic infection within wild mammals.

关键词： Isospora olfaction parasite scent scent preferences Toxocara.