117,436 research outputs found
Semi-quantitative assessment of 99Tcm-sestamibi uptake in lung cancer: relationship with clinical response to chemoterapy
No full textThe objectives of this study were to measure semi-quantitatively uptake of 99Tcm-sestamibi (99Tcm-MIBI) by tumour tissue in patients with lung cancer and to investigate its relationship with clinical response to chemotherapy. 99Tcm-MIBI single photon emission tomography was performed at the time of diagnosis in 31 patients with biopsy-proven lung cancer (19 small cell carcinomas, 12 non-small cell carcinomas), all of whom were undergoing chemotherapy. Fifteen patients were also investigated 2 weeks after the first and third cycles of chemotherapy. To quantify 99Tcm-MIBI uptake, a tumour/lung (T/L) ratio was calculated for the tomographic slices. The response to chemotherapy was rated as complete remission, partial remission or no remission using dimensional criteria. The results were expressed as the median and inter-quartile range; non-parametric statistical analyses were used. Forty one neoplastic localizations (31 primary tumours and 10 hilar or mediastinal lymph node masses) were assessed. The median T/L ratio of the primary tumours was 1.85 (range 1.7-2.4). Patients with a different response to chemotherapy had a significantly different median T/L ratio before chemotherapy: complete remission (n = 8), T/L ratio = 2.95 (range 2.20-3.25); partial remission (n = 10), 2.15 (range 1.77-2.40); no remission (n = 13), 1.70 (range 1.47-1.75) (Kruskal-Wallis, P < 0.0001). A T/L ratio of 1.80 gave sensitivity of 83\%, specificity of 85\% and accuracy of 84\% in the prediction of the response to chemotherapy. The patients with small cell carcinomas demonstrated greater 99Tcm-MIBI uptake than those with non-small cell carcinomas: T/L ratio, median 2.30 (range 1.76-3.00) vs 1.70 (range 1.50-1.78) (Mann-Whitney U-test, P = 0.001). No significant difference in 99Tcm-MIBI uptake was observed between the 10 lymph node metastases and the corresponding primary tumours: T/L ratio, median 2.30 (range 1.75-2.50) vs 2.15 (1.77-3.00) (Wilcoxon's paired samples rank test, N.S.). Of the 15 patients who were monitored with scintigraphy during chemotherapy, 10 showed complete or partial remission and a parallel reduction in their T/L ratio. The other five patients showed no response to chemotherapy and their T/L ratio was either unaffected or increased. We conclude that the semi-quantitative assessment of 99Tcm-MIBI uptake may have a significant role to play in the management of lung cancer, providing an effective means of predicting the efficacy of chemotherapy and of selecting subgroups of patients requiring radiotherapy or combined protocols before the start of treatment. 99Tcm-MIBI imaging may also be of use in monitoring clinical response to chemotherapy
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
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
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