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Charakterisierung und Distribution der Innervation menschlicher Koronararterien
No full textHintergrund: Das autonome Nervensystem des Herzens spielt eine entscheidende Rolle bei der Regulation kardialer Funktionen. Bisher sind nur wenige Daten über die Innervation der Koronararterien des Menschen bekannt. Eine erhöhte sympathische Aktivität kann zu verschiedenen kardiovas- kulären Erkrankungen wie beispielsweise Herzinsuffizienz, plötzlichem Herztod, Arrhythmien oder vasospastischer Angina pectoris führen. Die anatomische Charakterisierung und Distribu- tion dieser perivaskulären Nervenfasern kann wichtige Informationen über den Einfluss des autonomen Nervensystems auf die Funktion und Perfusion des Herzens liefern. Darüber hinaus ist ein detailliertes Verständnis der sympathischen Innervation der Koronararterien wichtig für die Entwicklung neuer therapeutischer Ansätze.
Methoden: Zur Analyse der Innervation menschlicher Koronararterien wurden zunächst Herzen aus 28 Körperspendern entnommen. Die Gewebeproben wurden mit angrenzendem epikardialen Fett- gewebe entlang des Hauptstamms der Arteria coronaria sinistra (engl.: left main coronary artery, LMCA), des Ramus interventricularis anterior (engl.: left anterior descending artery, LAD), des Ramus circumflexus (engl.: left circumflex artery, LCX) und der Arteria coronaria dextra (engl.: right coronary artery, RCA) entnommen. Zur Charakterisierung der Nervenfa- sern wurden histologische Schnittpräparate angefertigt und eine Immunfluoreszenzfärbung (S-100, Tyrosinhydroxylase) durchgeführt. Die koronare Innervation wurde manuell mit Hilfe einer digitalen Pathologiesoftware auf der Grundlage der Immunfluoreszenzfärbung quantitativ analysiert.
Ergebnisse: Insgesamt wurden 42.573 Nervenfasern entlang 100 Koronararterien analysiert (LMCA: n=21, LAD: n=27, LCX: n=26, RCA: n=26). Der Nervenfaserdurchmesser nahm entlang des Gefäß- verlaufs von proximal nach distal ab (Median [Interquartilsabstand]): proximal betrug dieser 46 μm [31-73 μm], im mittleren Bereich 38 μm [26-58 μm] und distal 31 μm [22-46 μm] (je- weils p<0,001), mit dem größten Nervenfaserdurchmesser entlang der LMCA (50 μm [31-81 μm]), gefolgt von der LAD (42 μm [27-72 μm]; p<0,001). Insgesamt war die Nervenfa- serdichte entlang der RCA am höchsten (123 Nervenfasern/cm2 [82-194 Nervenfasern/cm2]). Zirkumferentiell war die Nervenfaserdichte auf der Seite des Gefäßes, die dem Myokard zuge- wandt war, höher (132 Nervenfasern/cm2 [76-225 Nervenfasern/cm2]) als auf der Seite des Ge- fäßes, die der Lamina visceralis pericardii des Epikards zugewandt war (101 Nervenfasern/cm2 [61-173 Nervenfasern/cm2]; p<0,001). Die mediane Lumen-Nervenfaser-Distanz (LND) war entlang der LMCA (2,2 mm [1,2-4,1 mm]) am geringsten, gefolgt von der LAD (2,5 mm [1,1- 4,5 mm]; p=0,005).
Schlussfolgerung: Die Koronararterien des Menschen sind in hohem Maße von sympathischen Nervenfasern innerviert, wobei sich die Verteilung und die Dichte dieser Fasern zwischen den einzelnen Koronararterien signifikant unterscheidet. Das Verständnis dieser Innervationsmuster trägt zum pathophysiologischen Verständnis und möglicherweise zur Entwicklung katheterbasierter Ansätze zur autonomen Modulation des Herzens bei.Background: The autonomic nervous system of the heart plays a crucial role in regulating cardiac function. However, there has been limited research on human coronary innervation. Increased sympa- thetic activity can contribute to several cardiovascular diseases, including heart failure, sudden cardiac death, arrhythmias, and vasospastic angina. Understanding the anatomy and distribution of these perivascular nerves can provide important information on the impact of the autonomic nervous system on myocardial function and perfusion. Additionally, a detailed understanding of the sympathetic innervation of coronary arteries is critical to facilitate the development of novel treatment approaches.
Methods: Human hearts were taken from 28 body donors. Tissue samples were excised with adjacent epicardial adipose tissue along the left main coronary artery (LMCA), the left anterior descen- ding artery (LAD), the left circumflex artery (LCX), and the right coronary artery (RCA). Sections were prepared and immunofluorescence staining (S-100, tyrosine hydroxylase) was performed to characterize sympathetic nerve fibers. Coronary innervation was quantitatively analyzed using digital pathology software based on immunofluorescence staining.
Results: A total of 42,573 nerve fibres surrounding 100 coronary arteries (LMCA: n=21, LAD: n=27, LCx: n=26, RCA: n=26) were analysed. The nerve fibre diameter decreased along the vessel course (median [interquartile range]): proximal 46 μm [31-73 μm], middle 38 μm [26-58 μm], distal 31 μm [22-46 μm], (respectively p<0.001), with the largest nerve fibre diameter along the LMCA (50 μm [31-81 μm]), followed by the LAD (42 μm [27-72 μm]; p<0.001). The total nerve fibre density was highest along the RCA (123 nerves/cm2 [82-194 nerves/cm2]). Nerve density was higher on the side of the vessel facing the myocardium (132 nerves/cm2 [76- 225 nerves/cm2]) than on the side of the vessel facing the lamina visceralis pericardii of the epicardium (101 nerves/cm2 [61-173 nerves/cm2]; p<0.001). The median lumen-nerve distance was smallest around the LMCA (2.2 mm [1.2-4.1 mm]), followed by the LAD (2.5 mm [1.1- 4.5 mm]; p=0.005).
Conclusion: Human coronary arteries are richly innervated with sympathetic nerve fibres, with significant variation in the distribution and density. Understanding these patterns informs pathophysiolo- gical understanding and, potentially, the development of catheter-based approaches for cardiac autonomic modulation
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
Navigation systems in the Aegean sea in antiquity
No full textEge Denizi'ndeki adalar sulardan oluşmuş bariyerlerle ayrılmış bir biçimde bulunmaktadır fakat anakaraya yakın oldukları için yakın bulundukları kıyılar ile coğrafi bir birlik oluşturmaktadır. Antik dünyanın ağırlık merkezi İran ve Yakındoğu'dan batıya, Yunanistan'a kaydıktan sonra Akdeniz, gerek Yunan ve Roma uygarlıklarında gerek ticarette, gerekse yolculuklarda par excellence aracı rolünü üstlenmişti. Karada iç kısımlarda da bazı önemli Yunan yerleşimleri olmasına rağmen, Atina, Korinth, Sirakuza, Miletos gibi zengin şehirlerin tümü limandır. Böyle olması kaçınılmazdı; her yaz, her biri yaklaşık 100 pound ağırlığında, iki ya da üç bin galon yağı yüzlerce mil uzaktaki pazarlara götüren bir tüccar mütevazı büyüklükte tek bir gemiyle bunları taşıyabiliyordu. Hava iyi olduğu takdirde deniz yolculuğu hiç de kötü değildi. Yolcu yiyeceğini, içeceğini depolayıp, donanımını yükleyince yapacak işi kalmazdı: Gemi onun hanı olur, işi rüzgar ya da kürekler görürdü. Akdeniz ve Ege'de yolculuk ederken hızı ve rotayı belirleyen temel unsur yaz rüzgarlarıydı. Kuzeyden esen bu rüzgarlara "etezyen" ya da halk deyişiyle "meltemler" denirdi. Gemi bu rüzgarları arkasına aldığı zaman, rüzgar yönünde istediği yere rahatlıkla seyahat edebilirdi fakat dönüş yolculuğu aynı rahatlıkta gerçekleşmezdi. Bunun nedeni, dönüş yolculuğunun büyük bölümünü ters yönden esen rüzgarlara karşı yapmanın gerekli olmasıydı. Rotalarını da bu bağlamda rüzgarların esme yönleri ve zamanlarına göre belirlemeleri gerekiyordu. Mevki, yön ve mesafe navigasyonun üç ana elemanıdır. Amaç teknenin bulunduğu mevkinin, seyir ettiği yönün, mesafeyi de kapsayan gideceği rotanın tayin edilmesidir. Rota tayin ederken ise çeşitli navigasyon aletlerinden faydalanılmıştır.The islands of Aegean Sea, territorial units isolated by the barrier of the waters, but with close ties with the nearby mainland shores, constitute a unity as a geographical concept. The great sea routes pass through the world of the Aegean. Landing places and supply points for shipping in times both of the burgeoning of trade and of the outbreak of war, the ports and anchorages of the islands od the Aegean carrying warriors, merchandise, pilgrims, crusaders, rediscovery and antiquarianism have succeeded one another and have gone on side by side. When traveling in the Mediterranean and the Aegean, summer winds were the main factor determining the speed and the route. These winds blowing from the north were called breezes by ethereal or popular sayings. When the ship took these winds back, it could travel comfortably wherever it wanted in the direction of the wind, but the return journey would not take place in the same comfort. The reason for this is that most of the return journey was to do against the winds that wind in the opposite direction. In this context, they had to determine their course according to the direction and timing of the winds. The location, direction and distance are the three main elements of navigation. The aim is to designate the route that the craft will travel, including the direction it is cruising, including the distance. Various navigation devices have been used to determine the route
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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