10,579 research outputs found

    Functionalized Single-walled Nanotubes And Methods Thereof

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    Described are single-walled metal oxide nanotubes having a plurality of organic functional units or moieties bonded generally in a covalent manner to the inner wall of the single-walled nanotubes. Functionalization of the single-walled metal oxide nanotubes is performed in a single-step during synthesis of the nanotubes. The organic functional units are found dispersed throughout the length of the inner wall and not sterically hindered or contained at only the mouth or ends of the single-walled metal oxide nanotubes.Georgia Tech Research Corporatio

    Method and apparatus for magnetoresistive monitoring of analytes in flow streams

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    Method and apparatus for manipulating and monitoring analyte flowing in fluid streams. A giant magnetoresistive sensor has an array of sensing elements that produce electrical output signals which vary in dependence on changes in the magnetic field proximate the sensing elements. The analyte is included in a stream, such that the stream has a magnetic property which is dependent on the concentration and distribution on the analyte therein. The stream is flowed past the giant magnetoresistive sensor and in sufficiently close proximity to cause the magnetic properties of the stream to produce electrical output signals. The electrical output signals are monitored as an indicator of analyte concentration or distribution in the stream flowing past the GMR sensor. Changes in the magnetic field produced by the background stream are introduced by analyte molecules, whose presence in the flow past the GMR will effect the output reading

    From ab initio quantum mechanics to molecular neurobiology: A cation-pi binding site in the nicotinic receptor

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    The nicotinic acetylcholine receptor is the prototype ligand-gated ion channel. A number of aromatic amino acids have been identified as contributing to the agonist binding site, suggesting that cation-pi interactions may be involved in binding the quaternary ammonium group of the agonist, acetylcholine. Here we show a compelling correlation between: (i) ab initio quantum mechanical predictions of cation-pi binding abilities and (ii) EC50 values for acetylcholine at the receptor for a series of tryptophan derivatives that were incorporated into the receptor by using the in vivo nonsense-suppression method for unnatural amino acid incorporation. Such a correlation is seen at one, and only one, of the aromatic residues-tryptophan-149 of the alpha subunit. This finding indicates that, on binding, the cationic, quaternary ammonium group of acetylcholine makes van der Waals contact with the indole side chain of alpha tryptophan-149, providing the most precise structural information to date on this receptor. Consistent with this model, a tethered quaternary ammonium group emanating from position alpha 149 produces a constitutively active receptor

    Oceanus.

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    v. 26, no. 2 (1983

    English for Study and Work: Coursebook in 4 books. Book 2 Obtaining and Processing Information for Specific Purposes

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    Подано всі види діяльності студентів з вивчення англійської мови, спрямовані на розвиток мовної поведінки, необхідної для ефективного спілкування в академічному та професійному середовищах. Містить завдання і вправи, типові для різноманітних академічних та професійних сфер і ситуацій. Структура організації змісту – модульна, охоплює мовні знання і мовленнєві вміння залежно від мовної поведінки. Даний модуль має на меті розвиток у студентів стратегій, умінь, навичок читання, пошуку та вилучення професійно-орієнтованої інформації, необхідної для ефективної професійної діяльності і навчання. Містить завдання і вправи, типові для академічних та професійних сфер, пов’язаних з гірництвом і розробкою родовищ корисних копалин. Зразки текстів – автентичні, різножанрові, взяті з реального життя, містять цікаву й актуальну інформацію про особливості видобутку мінеральних ресурсів в провідних країнах світу, сучасний підхід до розробки родовищ тощо. Ресурси для самостійної роботи (Частина ІІ) містять завдання та вправи для розширення словникового запасу та розвитку знань найуживанішої термінології з гірництва, що спрямовано на організацію самостійної роботи з розвитку мовленнєвих умінь, знань про корисні копалини, методи їх видобутку. За допомогою засобів діагностики студенти можуть самостійно перевірити засвоєння навчального матеріалу й оцінити свої досягнення. Призначений для студентів вищих навчальних закладів, зокрема технічних університетів. Може використовуватися для самостійного вивчення англійської мови викладачами, фахівцями і науковцями різних галузей

    Optically switched magnetism in photovoltaic perovskite CH3_3NH3_3(Mn:Pb)I3_3

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    The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH3_3NH3_3(Mn:Pb)I3_3 material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low power, light controlling magnetic devices

    The nuclear magnetic resonance analyses of some geometric isomers.

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    The research problem presented herein involved the structural determination of several a,~-unsaturated acids and esters. The solution to this problem was sought in the nuclear magnetic resonance (n.m.r.) spectra of these compounds. The n.m.r. approach to structural problems in organic chemistry has been investigated extensively in the past ten years and it has proven to be an extremely powerful tool for this type of analysis. The data used in the structural determinations are presented in tabulated fo~, and in. the appendix tracings of the original spectra may be found. Each compound is discussed separately with respect to its probable structure and its recorded spectrum. Two brief sections follow the discussion of the spectra. One of these concerns a stereospecific solvent effect and the other relates to the effect of an anisotropic neighboring double bond on proton r -values. The configurational aSSignments for the various compounds were made possible by observing the changes in chemical shift for particular protons in different isomers and by comparison of the observed spin coupling constants with those reported in the literature. Allmost all of the compounds discussed in this thesis were of such a nature that their spectra could be interpreted on a simple first order basis. In the limited number of cases which involved more complex spectra, some approximations were attempted which made possible the assignment of configuration at several bonds. In some cases the assignments were not conclusive, but they found strong support in the approximate treatments given the complex splitting patterns

    Aspects of the biology and behaviour of Lernaeocera branchialis (Linnaeus, 1767)(Copepoda : Pennellidae)

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    Lernaeocera branchialis (L., 1767) is a parasitic copepod that parasitises a range of gadoids by anchoring in the proximity of the branchial chamber of its host, deriving nutrition from the blood of its host and causing serious pathogenic effects. This study investigates the taxonomy of the juvenile free-swimming stages and host location behaviour in the pre-metamorphosed adult female. The large size and distinctive appearance of the metamorphosed adult female stage, coupled with the wide exploitation and commercial importance of one of its principle final gadoid hosts, the cod (Gadus morhua L.), means that this species has long been recognised in the scientific literature, and here the extensive literature concerning this potentially important and damaging pathogen is re-examined to provide an up to date overview, which includes both aquaculture and wild fisheries perspectives. Due to disagreements between several descriptions of the L. branchialis juvenile stages, and because the majority of the descriptions are over 60 years old, the juvenile free-swimming stages are re-described, using current terminology and a combination of both light and confocal microscopy. The time of hatching and moults in these stages is also examined. Techniques for the automated creation of taxonomic drawings from confocal images using computer software are investigated and the possibilities and implications of this technique are discussed. The method of host location in L. branchialis is unknown but is likely to involve a variety of mechanisms, possibly including chemo-reception, mechano-reception and the use of physical phenomena in the water column, such as haloclines and thermoclines, to search for fish hosts. In this study the role of host-associated chemical cues in host location by adult female L. branchialis is investigated by analysing the parasites behavioural responses to a range of host-derived cues, in both a choice chamber and a 3D tracking arena. To analyse the data from the experiments, specialised computer software (“Paratrack”) was developed to digitise the paths of the parasites’ movements, and calculate a variety of behavioural parameters, allowing behaviour patterns to be identified and compared. The results show that L. branchialis responds to host-associated chemical cues in a similar way to many copepods in the presence of chemical cues. Of the different cues tested, gadoid conditioned water appears to be most attractive to the parasites, although the wide variation in behavioural responses may indicate that other mechanisms are also required for host location. The different behavioural responses of parasites to whiting (Merlangius merlangus L.) and cod (Gadus morhua) conditioned water, which are both definitive hosts, provide some evidence for sub-speciation in L. branchialis. The role of chemical cues in host location of L. branchialis, and the relative importance of chemical and physical cues in host location are discussed. As well as demonstrating several techniques, which show potential for further development, this work has improved our knowledge of the biology and life-cycle of L. branchialis. Further study of this, and other areas of L. branchialis biology and its host-parasite interactions, should assist the development of contingency plans for the effective management and control of this widespread and potentially devastating pathogen
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