1,721,112 research outputs found
Raman and FTIR imaging of lung tissue: methodology for controlsamples
No full textThe paper describes Raman and FTIR images of normal lung tissue of an infant patient which is a prerequisite to understand the biochemical changes that accompany pediatric lung pathologies and malformations. A Raman image of 3420 spectra was recorded from a 5.7 mm x 6 mm tissue section in mapping mode using 785 nm excitation laser and a step size of 100 mu m. A Fourier transform infrared (FTIR) image of 4096 spectra was recorded from the same sample at a lateral resolution of 63 mu m using a spectrometer coupled to a focal plane array detector. Whereas the analysis of the FTIR image was complicated by dispersion artifacts, the analysis of the Raman image was impaired by intense spectral contributions of hemoglobin which overlap with spectral contributions of other proteins, lipids and nucleic acids. Data analysis procedures were optimized to reduce these effects. A multiplicative signal correction was performed to normalize the spectra within each dataset. Then, pseudo color images were constructed using cluster analyses. The most significant variations within both images were assigned to different concentrations of red blood cells. Furthermore, mucus and blood vessels were identified in the vibrational spectroscopic images. The different sensitivity of Raman and FTIR imaging for lung tissue constituents supports the combined use of both modalities
Biomedical applications of Raman andinfrared spectroscopy to diagnose tissues
Full text linkThe objective of the article is to review biomedical applications which became possible after the development of sensitive and high throughput Raman and Fourier transform infrared spectrometers in the past decade. Technical aspects of the instrumentation are briefly described. Then the broad range of vibrational spectroscopic applications with the focus on imaging and fiber-optical methods are discussed to study mineralized tissue (bone, teeth), skin, brain, the gastrointestinal tract (mouth, pharynx, esophagus, colon), breast, arteries, cartilage, cervix uteri, the urinary tract (prostate, bladder), lung, ocular tissue, liver, heart and spleen. Experimental studies are summarized demonstrating the possibilities and prospects of these methods in various fields of biodiagnostics to detect and characterize diseases, tumors and other pathologies
Disease recognition by infrared and Raman spectroscopy.
No full textInfrared (IR) and Raman spectroscopy are emerging biophotonic tools to recognize various diseases. The current review gives an overview of the experimental techniques, data-classification algorithms and applications to assess soft tissues, hard tissues and body fluids. The methodology section presents the principles to combine vibrational spectroscopy with microscopy, lateral information and fiber-optic probes. A crucial step is the classification of spectral data by a variety of algorithms. We discuss unsupervised algorithms such as cluster analysis or principal component analysis and supervised algorithms such as linear discriminant analysis, soft independent modeling of class analogies, artificial neural networks support vector machines, Bayesian classification, partial least-squares regression and ensemble methods. The selected topics include tumors of epithelial tissue, brain tumors, prion diseases, bone diseases, atherosclerosis, kidney stones and gallstones, skin tumors, diabetes and osteoarthritis
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
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
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