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Magnetic resonance imaging of the fetal brain
No full textÖZET Erdal, HH, Fetal Beynin Manyetik Rezonans ile Görüntülenmesi, Kırıkkale Üniversitesi Tıp Fakültesi Radyodiagnostik Anabilim Dalı Uzmanlık Tezi, Kırıkkale, 2004. Fetal Beyinin Manyetik Rezonans ile görüntülenmesi (MRG), potansiyel ve bilinmeyen yan etkileri nedeniyle, tanı için ultrasonografik görüntüleme (USG) sonuçlarının yetersiz kaldığı durumlarda, anne ve fetüsün doğru tedaviyi alabilmesi için danışma kaynağı olarak kullanılabilir. Ülkemizde gebeler için rutin görüntüleme modalitesi olmayan, fetal MRG'nin, radyoloji pratiğine ne ölçüde girebileceğini ve etkinliğini gösterebilmek amacıyla, toplam 34 gebe olguya fetal MRG tetkiki uygulandı. Fetal beyinin aksiyel, koronal ve sagittal planlarda ortogonal görüntülerini elde etmek için 1,5 Tesla Manyetik rezonans cihazında, ağır T2 single- shot turbo spin echo (SS-TSE) sekansı uygulandı. Elde edilen imajlar, bir nöroradyolog tarafından değerlendirildi. İncelenen olgularda patoloji saptanmadı. Ülkemizin sosyoekonomik şartlan ve fetal MRG'nin potansiyel ve bilinmeyen yan etkileri değerlendirildiğinde, MRG'nin tüm gebelerde uygulanabilmesi mümkün değildir, ancak USG'nin tamamlayıcısı ve destekleyicisi olabilecek bir yöntemdir. Anahtar Kelimeler: Manyetik rezonans görüntüleme, fetüs, beyin, tek vuruş turbo spin eko.VI ABSTRACT Erdal, HH, Magnetic resonance imaging of the fetal brain, University of KIRIKKALE, Faculty of Medicine, Department of Radiology, Radiodiagnosis Thesis, KIRIKKALE, 2004. Magnetic resonance imaging (MRI) of the fetal brain has several potential and unknown side effects. Therefore, it should be used to determine the appropriate treatment for the mother and fetus only when ultrasonographic imaging (USI) techniques are insufficient. To this date fetal MRI has not been a commonly used modality in our country. We have used fetal MRI on thirty-four patients in order to demonstrate the efficiency and the future possible use in radiology practice in Turkey. Heavy T2 single shot turbo spin echo (SS-TSE) sequence has been applied with a 1.5 Tesla MRI device in order to obtain the axial, coronal and sagittal views of the fetal brain. Obtained images have been viewed by a neuroradiology expert and no pathologies were found. It is not possible to use MRI for all expectancy cases due to the limited economic resources of our country and potential side effects of MRI. However, MRI is a modality which can be used to complement USI modalities. Keywords: Magnetic resonance imaging, fetus, brain, single shot turbo spin echo
Evaluation of cerebral hemodynamic changes in normal pregnancy by transranial doppler ultrasonography
No full textÖZET Şimşir, L, Normal Gebelerde Serebral Hemodinamik Değişikliklerin Transkranial Doppler Ultrasonografi İle Değerlendirilmesi, Kırıkkale Üniversitesi Tıp Fakültesi Radyodiagnostik Anabilim Dalı Uzmanlık Tezi, Kırıkkale, 2004. Transkranial Doppler Ultrasonografi (TKDU), serebrovasküler hemodinamiklerin ve otoregülasyonun değerlendirilmesinde nöroloji ve nöroşirurjide yaygın olarak kullanılan noninvaziv, basit bir tekniktir. Normal gebelikte serebral sirkülasyona yönelik çalışma azdır. Çalışmamızda komplikasyonsuz gebelerde, gebelikleri boyunca gelişen anterior ve posterior serebral hemodinamideki değişiklikleri göstermeyi amaçladık. Çalışmaya yaşları 1 7-3 1 yıl arasında değişen 79 gebe ve yaşları 16-35 yıl arası değişen 28 sağlıklı birey alındı. Tüm olgulara TKDU ve internal karotis (İKA)-vertebral artere (VA) yönelik renkli Doppler ultrasonografi yapıldı. Her bir arterin bilateral akım volümü, akım hızı, rezistivite ve pulsatilite indeksleri ölçüldü. Bu değerler, her trimesterde ayrı ayrı ve kontrol grubu ile karşılaştırıldı. Bu bulgulara göre, 1.trimesterde bilateral orta serebral arter (OSA) ve posterior serebral arter (PSA) kan volümünde ve bilateral OSA pik sistolik ve ortalama kan akım hızlarında artma, 3. trimesterde ise OSA ve ASA'de ortalama kan akım hızlarında istatiksel olarak anlamlı azalma saptandı. Tüm gebelik süresince bilateral OSA ve sağ İKA RI değeri, kontrol grubundan anlamlı yüksek bulundu. Sonuç olarak bu çalışmada elde ettiğimiz bulgular, gebelikteki serebral hemodinamik değişikliklerin TKDU ile değerlendirilebileceğini ve riskli gebelerin izlenmesinde yol gösterebileceğini düşündürmektedir. Anahtar Kelimeler: Transkranial Doppler Ultrasonografi, Willis poligonu, Gebelik, Serebral Hemodinami.VI ABSTRACT Şimşir, L, Evaluation of Cerebral Hemodynamic Changes in Normal Pregnancy by Transcranial Doppler Ultrasonography, University of KIRIKKALE, Faculty of Medicine, Departmant of Radiology, Radiodiagnosis Thesis, KIRIKKALE, 2004. Transcranial Doppler Ultrasonography (TCD) is a simple and noninvasive technique that is becoming more commonly used in neurology and neurosurgical circles to evaluate cerebrovascular hemodynamics and autoregulation. There are few studies about cerebral circulation in normal pregnancy. In our study we aimed to demonstrate anterior and posterior cerebral hemodynamic changes throughout pregnancy in uncomplicated pregnancies. Our study consisted of 79 pregnants (ages between 17-31 year) and 28 healty individuals (ages between 16-35 year). TCD and color Doppler ultrasonography on internal carotis-vertebral artery (1CA-VA) were applied to all cases. Bilateral volume, flow velocity, resistivity (RI) and pulsatility indexes (PI) were measured for each artery. These values were compared with control group at each trimester separately. According to our data, statistically significant increase at first trimester in blood volume at bilateral middle cerebral artery (MCA) and posterior cerebral artery (PCA), peak systolic and mean flow velocity at bilateral MCA, and decrease at third trimester in mean flow velocity at MCA and anterior cerebral artery (ACA) were found. Throughout entire pregnancy bilateral MCA and RI of right ICA were found significantly higher than the control group. In conclusion, results of this study proves that cerebral hemodynamic changes in pregnancy can be assessed by TCD which can be used for evaluation of risky pregnancies. Keywords: Transcranial Doppler Ultrasonography, Pregnancy, Cerebral Hemodynamic Changes, Willis Polygo
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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