176 research outputs found
Consumption of single cigarettes and quitting behavior: A longitudinal analysis of Mexican smokers
<p>Abstract</p> <p>Background</p> <p>Previous cross-sectional research has suggested single cigarettes could either promote or inhibit consumption. The present study aimed to assess the effects of single cigarette availability and consumption on downstream quit behavior.</p> <p>Methods</p> <p>We analyzed population-based, longitudinal data from adult smokers who participated in the 2008 and 2010 administrations of the International Tobacco Control Policy Evaluation Survey in Mexico.</p> <p>Results</p> <p>At baseline, 30% of smokers saw single cigarettes for sale on a daily basis, 17% bought singles at their last purchase, and 7% bought singles daily. Smokers who most frequently purchased singles, both in general and specifically to control their consumption, were no more likely to attempt to quit over the 14 month follow-up period than those who did not purchase singles. Frequency of buying singles to reduce consumption had a non-monotonic association with being quit at followup. The odds of being quit was only statistically significant when comparing those who had not bought singles to reduce consumption with those who had done so on a more irregular basis (AOR = 2.30; 95% CI 1.19, 4.45), whereas those who did so more regularly were no more likely to be quit at followup. Frequency of self-reported urges to smoke upon seeing singles for sale was unassociated with either quit attempts or being quit at followup.</p> <p>Conclusions</p> <p>These results suggest that the relationship between singles consumption and quit behavior is complex, with no clear evidence that singles either promote or inhibit downstream quit behavior.</p
Microscale characterization of prostate biopsies tissues using optical coherence elastography and second harmonic generation imaging
© 2018 USCAP, Inc All rights reserved. Photonics, especially optical coherence elastography (OCE) and second harmonic generation (SHG) imaging are novel high-resolution imaging modalities for characterization of biological tissues. Following our preliminary experience, we hypothesized that OCE and SHG imaging would delineate the microstructure of prostate tissue and aid in distinguishing cancer from the normal benign prostatic tissue. Furthermore, these approaches may assist in characterization of the grade of cancer, as well. In this study, we confirmed a high diagnostic accuracy of OCE and SHG imaging in the detection and characterization of prostate cancer for a large set of biopsy tissues obtained from men suspected to have prostate cancer using transrectal ultrasound (TRUS). The two techniques and methods described here are complementary, one depicts the stiffness of tissues and the other illustrates the orientation of collagen structure around the cancerous lesions. The results showed that stiffness of cancer tissue was ∼57.63% higher than that of benign tissue (Young's modulus of 698.43±125.29 kPa for cancerous tissue vs 443.07±88.95 kPa for benign tissue with OCE. Using histology as a reference standard and 600 kPa as a cut-off threshold, the data analysis showed sensitivity and specificity of 89.6 and 99.8%, respectively. Corresponding positive and negative predictive values were 99.5 and 94.6%, respectively. There was a significant difference noticed in terms of Young's modulus for different Gleason scores estimated by OCE (P-value<0.05). For SHG, distinct patterns of collagen distribution were seen for different Gleason grade disease with computed quantification employing a ratio of anisotropic to isotropic (A:I ratio) and this correlated with disease aggressiveness
The limits of corporate social responsibility : Techniques of neutralization, stakeholder management and political CSR
Since scholarly interest in corporate social responsibility (CSR) has primarily focused on the synergies between social and economic performance, our understanding of how (and the conditions under which) companies use CSR to produce policy outcomes that work against public welfare has remained comparatively underdeveloped. In particular, little is known about how corporate decision-makers privately reconcile the conflicts between public and private interests, even though this is likely to be relevant to understanding the limitations of CSR as a means of aligning business activity with the broader public interest. This study addresses this issue using internal tobacco industry documents to explore British-American Tobacco’s (BAT) thinking on CSR and its effects on the company’s CSR Programme. The article presents a three-stage model of CSR development, based on Sykes and Matza’s theory of techniques of neutralization, which links together: how BAT managers made sense of the company’s declining political authority in the mid-1990s; how they subsequently justified the use of CSR as a tool of stakeholder management aimed at diffusing the political impact of public health advocates by breaking up political constituencies working towards evidence-based tobacco regulation; and how CSR works ideologically to shape stakeholders’ perceptions of the relative merits of competing approaches to tobacco control. Our analysis has three implications for research and practice. First, it underlines the importance of approaching corporate managers’ public comments on CSR critically and situating them in their economic, political and historical contexts. Second, it illustrates the importance of focusing on the political aims and effects of CSR. Third, by showing how CSR practices are used to stymie evidence-based government regulation, the article underlines the importance of highlighting and developing matrices to assess the negative social impacts of CSR
Tandem E2F Binding Sites in the Promoter of the p107 Cell Cycle Regulator Control p107 Expression and Its Cellular Functions
The retinoblastoma tumor suppressor (Rb) is a potent and ubiquitously expressed cell cycle regulator, but patients with a germline Rb mutation develop a very specific tumor spectrum. This surprising observation raises the possibility that mechanisms that compensate for loss of Rb function are present or activated in many cell types. In particular, p107, a protein related to Rb, has been shown to functionally overlap for loss of Rb in several cellular contexts. To investigate the mechanisms underlying this functional redundancy between Rb and p107 in vivo, we used gene targeting in embryonic stem cells to engineer point mutations in two consensus E2F binding sites in the endogenous p107 promoter. Analysis of normal and mutant cells by gene expression and chromatin immunoprecipitation assays showed that members of the Rb and E2F families directly bound these two sites. Furthermore, we found that these two E2F sites controlled both the repression of p107 in quiescent cells and also its activation in cycling cells, as well as in Rb mutant cells. Cell cycle assays further indicated that activation of p107 transcription during S phase through the two E2F binding sites was critical for controlled cell cycle progression, uncovering a specific role for p107 to slow proliferation in mammalian cells. Direct transcriptional repression of p107 by Rb and E2F family members provides a molecular mechanism for a critical negative feedback loop during cell cycle progression and tumorigenesis. These experiments also suggest novel therapeutic strategies to increase the p107 levels in tumor cells
Beta cell coupling and connexin expression change during the functional maturation of rat pancreatic islets
Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds
The limits of modifying migration speed to adjust to climate change
Predicting the range of variation over which organisms can adjust to environmental change is a major challenge in ecology(1,2). This is exemplified in migratory birds which experience changes in different habitats throughout the annual cycle(3). Earlier studies showed European population trends declining strongest in migrant species with least adjustment in spring arrival time(4,5). Thus, the increasing mismatches with other trophic levels in seasonal breeding areas(6,7) probably contribute to their large-scale decline. Here we quantify the potential range of adjusting spring arrival dates through modifying migration speeds by reviewing 49 tracking studies. Among individual variation in migration speed was mainly determined by the relatively short stop-over duration. Assuming this population response reflects individual phenotypic plasticity, we calculated the potential for phenotypic plasticity to speed-up migration by reducing stop-over duration. Even a 50% reduction-would lead to a mere two-day advance in arrival, considering adjustments on the final 2,000 km of the spring journey. Hence, in contrast to previous studies(8-10), flexibility in the major determinant of migration duration seems insufficient to adjust to ongoing climate change, and is unlikely to explain some of the observed arrival advancements in long-distance migrants
Characterization of nerve-induced relaxation of gastrointestinal sphincteric smooth muscle in a South American opossum (Didelphis albiventris)
Should essays and other “open-ended”-type questions retain a place in written summative assessment in clinical medicine?
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