118,968 research outputs found
Hormonal treatments and the breast : effects on sex steroid receptor expression and proliferation
No full textBreast cancer is the most common malignancy among women in the western world. Hormonal treatments for contraception and replacement after menopause have been associated with an increased risk of breast cancer. The basis of risk associated with hormonal therapies may lie in the regulation of cell proliferation.Normal breast tissue samples from 27 women undergoing reduction mammoplasties were analysed for sex steroid receptor content and proliferation. Women using hormonal contraceptives displayed a higher proliferation rate (p=0.05) expressed as Ki-67/MIB-1 positivity than non-users. Proliferation displayed a strong positive correlation with IGF-I mRNA expression in breast tissue (rs =0.82, p=0.04). During treatment there was a down regulation of ER values.FNA biopsies were used to assess epithelial proliferation in normal breast tissue from 106 healthy premenopausal women with and without oral contraceptives. OC users had a higher (p=0.03) proliferation rate (mean 4.8 % of KI-67/MIB-1 positive cells) than non-users (mean 2.2 %). Increased proliferation was associated with reduced levels of circulating androgens and free testosterone (rs =- 0.38, pSurgically postmenopausal cynomolgus macaques were treated for 35 months with either CEE, MPA, CEE/MPA or tamoxifen. Proliferation in breast tissue was associated (p=0.016) with increased expression of p53. Tamoxifen was found to exert estrogen-like action in breast tissue by down-regulation of estrogen receptor expression and increased PRB levels. In the endometrium the lack of p53 expression in response to tamoxifen could be associated with an increased risk of endometrial cancer. Estrogen alone and estrogen in combination with progestogen was found to have different effects on the expression of sex steroid receptor isoforms in breast tissue. During combined CEE/MPA treatment both the ER-beta/ER-alpha and the PRA/PRB ratio had a tendency to be lower as compared to treatment with CEE alone. Suppression of the inhibitory isoforms ER-beta and PRA may relate to increased proliferation during combined estrogen/progestogen treatment.Ongoing HRT at the time of breast cancer diagnosis was found to influence certain tumor characteristics. Among 322 postmenopausal women with breast cancer 128 were using HRT at diagnosis. In this group the mean tissue concentrations of ER were lower (1.17 fmol/µg DNA) than in non-users (1.70 µg/DNA), pList of scientific papersI. Isaksson E, Sahlin L, Soderqvist G, von Schoultz E, Masironi B, Wickman M, Wilking N, von Schoultz B, Skoog L (1999). Expression of sex steroid receptors and IGF-1 mRNA in breast tissue--effects of hormonal treatment. J Steroid Biochem Mol Biol. 70(4-6): 257-62. https://pubmed.ncbi.nlm.nih.gov/10622416II. Isaksson E, von Schoultz E, Odlind V, Soderqvist G, Csemiczky G, Carlstrom K, Skoog L, von Schoultz B (2001). Effects of oral contraceptives on breast epithelial proliferation. Breast Cancer Res Treat. 65(2): 163-9. https://pubmed.ncbi.nlm.nih.gov/11261832III. Isaksson E, Cline JM, Skoog L, Soderqvist G, Wilking N, von Schoultz E, von Schoultz B (1999). p53 expression in breast and endometrium during estrogen and tamoxifen treatment of surgically postmenopausal cynomolgus macaques. Breast Cancer Res. Treat 53(1): 61-7. https://pubmed.ncbi.nlm.nih.gov/10206073IV. Isaksson E, Wang H, Sahlin L, von Schoultz B, Masironi B, von Schoultz E, Cline JM (2002). Expression of estrogen receptors (alpha, beta) and insulin-like growth factor-I in breast tissue from surgically postmenopausal cynomolgus macaques after long-term treatment with HRT and Tamoxifen. Breast.V. Isaksson E, Wang H, Sahlin L, von Schoultz B, Cline JM, von Schoultz E (2002). Effects of long-term HRT and Tamoxifen on the expression of progesterone receptors A and B in breast tissue from surgically postmenopausal cynomolgus macaques. [Submitted]VI. Isaksson E, Mahlman M, Nilsson B, Skoog L, Lofgren L, Wilking N, von Schoultz E (2002). Hormone replacement therapy and estrogen receptor expression in breast cancer. [Submitted]</p
Assessing the value of radical technology alternatives at system level
No full textThis study investigates the challenge to assess value when alternative technologies - of radical nature - are integrated on complex products. The study highlights three main challenges: 1) value depends on how the overall product platform is impacted over time 2) value depends on combination effects between technologies and 3) value depends on how the technology balances internal and external stakeholders needs simultaneously. The paper describes how these challenges can be tackled by novel modelling methods, illustrated with an example related to structural batteries
Pseudoconvex proximal splitting for L-infinity problems in multiview geometry
No full textIn this paper we study optimization methods for minimizing large-scale pseudoconvex L∞ problems in multiview geometry. We present a novel algorithm for solving this class of problem based on proximal splitting methods. We provide a brief derivation of the proposed method along with a general convergence analysis. The resulting meta-algorithm requires very little effort in terms of implementation and instead makes use of existing advanced solvers for non-linear optimization. Preliminary experiments on a number of real image datasets indicate that the proposed method experimentally matches or outperforms current state-of-the-art solvers for this class of problems
Dynamic lifecycle cost modeling for adaptable design optimization of additively remanufactured aeroengine components
No full textAdditive manufacturing (AM) is being used increasingly for repair and remanufacturing of aeroengine components. This enables the consideration of a design margin approach to satisfy changing requirements, in which component lifespan can be optimized for different lifecycle scenarios. This paradigm requires lifecycle cost (LCC) modeling; however, the LCC models available in the literature consider mostly the manufacturing of a component, not its repair or remanufacturing. There is thus a need for an LCC model that can consider AM for repair/remanufacturing to quantify corresponding costs and benefits. This paper presents a dynamic LCC model that estimates cumulative costs over the in-service phase and a nested design optimization problem formulation that determines the optimal component lifespan range to minimize overall cost while maximizing performance. The developed methodology is demonstrated by means of an aeroengine turbine rear structure
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
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
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