130,372 research outputs found
How to understand Holoprosencephaly
No full textABSTRACT
Holoprosencephaly (HPE) is a group of complex structural malformations of the forebrain that results from complete or incomplete nonseparation of the prosencephalon that yields an incomplete division of the cerebral hemispheres and of the telencephalon from the diencephalon. According to the severity of the malformation, HPE is categorized into four subtypes: Alobar HPE, semilobar HPE, lobar HPE, and a middle interhemispheric fusion variant (syntelencephaly). The incidence of HPE is 1 in 10,000 to 15,000 births. The etiology of HPE is very heterogeneous, and the identified causes until now are: Chromosomal (most commonly trisomy 13), monogenic, and teratogenic. The first step of the diagnostics is based on the ultrasound visualization of cerebral ventricular abnormalities, on the axial plane of the fetal brain, and on the facial anomalies.
How to cite this article
Vladareanu R, Munteanu A, Ionescu CA, Navolan D, Vladareanu S. How to understand Holoprosencephaly. Donald School J Ultrasound Obstet Gynecol 2017;11(4):282-287.
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Advanced Ultrasound Application – Impact on Presurgical Risk Stratification of the Thyroid Nodules
No full textDana Stoian, 1, 2 Viviana Ivan, 1 Ioan Sporea, 1 Varcus Florian, 3 Ioana Mozos, 4 Dan Navolan, 5 Dragos Nemescu 6 1 2nd Department of Internal Medicine, “Victor Babes” University of Medicine, Timisoara, Romania; 2Dr. D Center for Ultrasound in Endocrinology, Timisoara, Romania; 3 2nd Department of Surgery, “Victor Babes” University of Medicine, Timisoara, Romania; 4Department of Physiopathology, “Victor Babes” University of Medicine, Timisoara, Romania; 5Department of Obstetrics Gynecology, “Victor Babes” University of Medicine, Timisoara, Romania; 6Department of Obstetrics Gynecology, “Gr. T. Popa” University of Medicine, Iasi, RomaniaCorrespondence: Dan NavolanDepartment of Obstetrics Gynecology, “Victor Babes” University of Medicine and Pharmacy Timisoara, P-ta Eftimie Murgu, Nr. 2, Timisoara 300011, RomaniaEmail [email protected] Ivan 2nd Department of Internal Medicine, “Victor Babes” University of Medicine and Pharmacy Timisoara, P-ta Eftimie Murgu, Nr. 2, Timisoara 300011, RomaniaTel +40 722 960 911Fax +40 256 020 1890Email [email protected]: Current major guidelines recommend risk stratification of the thyroid nodules, after each diagnostic evaluation, in order to focus attention on potentially risky nodules. The main aim of our study was to evaluate the performance of combined advanced ultrasound techniques in this process, compared with conventional stratification models, in order to reduce unnecessary fine-needle biopsies, respectively, surgery.Material and Methods: We evaluated 261 cases (261 nodules) using conventional ultrasound (2B), real-time Doppler evaluation (4D) respectively, real-time elastography, using a linear multifrequency probe and a linear volumetric probe (Hitachi Prerius Machine, Hitachi Inc, Japan). All the nodules were classified using a risk stratification model comprising seven conventional US characteristics, two 4 D characteristics and a color map RTE aspect. The results were compared with the pathology results, considered the golden standard diagnosis.Results: The prevalence of malignant nodules was 21.83% (57 cases). Conventional risk classification generated: 106 low-risk cases, 113 intermediate-risk and 42 high-risk cases. Our proposed risk classification changes the conventional risk classification with a risk upgrade in 27 cases and with a risk downgrade in 69 cases. The diagnostic quality of the combined risk stratification model was better, considering a low-risk category predictive for benignancy and a high category predictive for malignancy: Sensitivity: 80.88% versus 49.01%, respectively, Specificity: 91.22% versus 54.38. The diagnostic power differences were observed regardless of the nodule size.Conclusion: Advanced ultrasound techniques did add diagnostic value in the presurgical risk assessment of the thyroid nodules.Keywords: strain elastography, volumetric Doppler, complex ultrasound thyroid evaluation, risk stratificatio
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
The R&D Tax Incentives
No full textThis article sets out some background information and reflections of the author on the R&D tax incentive schemes included in the Common Corporate Tax Base (CCTB) Proposal. In particular the author analyzes the stimulus to private R&D through ad hoc tax incentives included in the CCTB Proposal and dives into the actual provisions included in the Proposal highlighting the most relevant issues connected with their design and interpretation. Moreover, the author explores the interaction between the CCTB Proposal and the granting by Member States of domestic R&D tax incentives
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