1,721,343 research outputs found
Mapping brain circuits : anatomy, connectivity and function
No full textTo decipher neural circuits anatomy is the central basis for all kinds of neurobiological studies. Here in this thesis, I will start with extensive overview of the current methods that have been intensively employed in labeling and mapping neurons and neuronal activities, including tracing techniques, imaging/recording systems and manipulation tools. This will be followed by the introduction of the two model systems that are being studied in this thesis.Specifically, the ultimate goal of this thesis is to examine the anatomical neural circuits of involving median prefrontal cortex and the serotonergic nuclei, by developing a standardized brain atlas for automatic processing and analyzing anatomical image data, which facilitate functional studies of the serotonergic neurons in rats.In paper I, we characterized the inputs to two major serotonergic nuclei using a retrograde trans-synaptic virus. We reconstructed a whole brain input map with customized software, and found previously undefined inputs. We also confirmed the existence of the functional connection from basal ganglia, lateral habenula, and prefrontal cortex to the raphe nuclei serotonergic neurons. In paper II, we developed a versatile interactive framework for automatic detection, registration, and analysis. In paper III, we characterized both the local and long-range inputs to four cell types in the mouse medial prefrontal cortex. A new viral strategy for tracing both local and long-range inputs at the same time was developed. We have confirmed the findings by other tracing techniques, and rebuilt our own connectivity map. In paper IV, we explored the roles of serotonergic neurons in impulsive behavior by manipulating and recording the neurons.In summary, we have developed new methods for neural circuitry study, added our knowledge of the serotonergic and median prefrontal cortex circuitry, and gained deeper insights of functional roles of serotonergic neurons.List of scientific papersI. Iskra Pollak Dorocic, Daniel Fürth, YANG XUAN, Yvonne Johansson, Laura Pozzi, Gilad Silberberg, Marie Carlén, Konstantinos Meletis. A whole-brain atlas of inputs to serotonergic neurons of the dorsal and median raphe nuclei. Neuron. 2014, Volume 83, Issue 3, 663-678. https://doi.org/10.1016/j.neuron.2014.07.002 II. Daniel Fürth, Thomas Vaissière, Ourania Tzortzi, YANG XUAN, Antje Märtin, Iakovos Lazaridis, Giada Spigolon, Gilberto Fisone, Raju Tomer, Karl Deisseroth, Marie Carlén, Courtney A. Miller, Gavin Rumbaugh & Konstantinos Meletis. An interactive framework for whole-brain maps at cellular resolution. Nature Neuroscience. 2018, 21, 139–149. https://doi.org/10.1038/s41593-017-0027-7 III. YANG XUAN, Sofie Ährlund-Richter, Hoseok Kim, Iskra Pollak Dorocic, Felix Wahl, Konstantinos Meletis, Marie Carlén. [Manuscript]IV. Xinming Wang, YANG XUAN, Hoseok Kim, Iskra Pollak Dorocic, Daniel Kaping, Marc Parent, Konstantinos Meletis, Marie Carlén. [Manuscript]</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Fast Screening and Confirmation of Multiple Control Drugs Using Ultra-High Performance Liquid Chromatography/Tandem Mass Spectrometry
No full text藥物濫用造成社會問題由來已久，尤其是未納入管制的新興濫用藥物諸如色胺類與苯乙胺等，使得藥物濫用問題日益複雜。本研究針對61種藥物包括管制藥物、新興濫用藥物與常見併用藥物，利用極致液相層析串聯三段式四極柱質譜儀開發快篩與確認方法。本研究選用Ascentis Express RP-Amide管柱 (50 * 2.1 mm, 2.7 μm) 搭配由乙腈與10 mM 醋酸胺溶液所組成之移動相，針對其中53種易於形成正離子之藥物進行層析，層析時間包括管柱再平衡共費時8.5分鐘；其餘8種易形成負離子之藥物，則使用Fortis H2o管柱 (30 * 2.1 mm, 1.7 μm) 並利用甲醇與0.5%乙酸組合作為移動相進行層析，層析時間包括管柱再平衡僅需時6.6分鐘。本研究使用胃乳片與amoxicillin粉末作為模擬基質，利用甲醇進行超音波萃取後，經高速離心並過濾再行上機分析。其中51種藥物在游離化的過程中，其訊號受到基質干擾之比率小於30%。本研究針對偵測極限與基質效應，比較電灑游離法與大氣壓光游離法二種游離源之表現，其結果顯示電灑游離法在二方面皆優於大氣壓光游離法。本研究並使用Chromalynx軟體建立濫用藥物資料庫；Chromalynx軟體原設計用於液相層析串聯飛行時間質譜儀，針對未知化合物進行快篩，本研究將之用於液相層析串聯三段式四極柱質譜儀，結果顯示成功的資料庫比對主要受到層析滯留時間、待測物分子量與待測物碎片形式所影響。The problem of drug abuse has been a long-term concern by societies, especially the increasing use on emerging drugs like tryptamines and psychedelic phenethylamines, which have not been included as control drugs. We developed a screening and confirmatory method for detecting 61 drugs including control drugs, emerging abused drugs and common combined-use drugs, with an ultra-high performance chromatography/triple-quadrupole mass spectrometer (UHPLC-QqQMS). Fifty three drugs forming positive ions were separated on an Ascentis Express RP-Amide column (50 * 2.1 mm, 2.7 μm) within 8.5 min including re-equilibrium with the mobile phase composed of acetonitrile and 10 mM ammonium acetate. The separation of eight drugs forming negative ions was achieved on a Fortis H2o column (30 * 2.1 mm, 1.7 μm) and took only 6.6 min with the mobile phase containing methanol and 0.5% acetic acid. In this study, we use antacid tablets and amoxicillin powder as the simulated matrixes; samples were extracted with sonication in methanol, then were centrifuged and filtered before injecting onto the instrument. The influence of matrix components to the ionization efficiency on 51 analytes was lower than 30%. We also compared the detection sensitivity and matrix effect between electrospray ionization (ESI) and atmospheric photoionization (APPI), and ESI was found to be better than APPI. The Chromalynx software, which was designed for fast screening of unknown compounds on a LC-time of flight-MS, was studied on the LC-QqQMS for this purpose. Retention time, analyte molecular weight, and patterns of fragmentation played crucial roles in a successful matching of library search
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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