583 research outputs found
Accurate Pulmonary Nodule Detection in Computed Tomography Images Using Deep Convolutional Neural Networks
Early detection of pulmonary cancer is the most promising way to enhance a
patient's chance for survival. Accurate pulmonary nodule detection in computed
tomography (CT) images is a crucial step in diagnosing pulmonary cancer. In
this paper, inspired by the successful use of deep convolutional neural
networks (DCNNs) in natural image recognition, we propose a novel pulmonary
nodule detection approach based on DCNNs. We first introduce a deconvolutional
structure to Faster Region-based Convolutional Neural Network (Faster R-CNN)
for candidate detection on axial slices. Then, a three-dimensional DCNN is
presented for the subsequent false positive reduction. Experimental results of
the LUng Nodule Analysis 2016 (LUNA16) Challenge demonstrate the superior
detection performance of the proposed approach on nodule detection(average
FROC-score of 0.891, ranking the 1st place over all submitted results).Comment: MICCAI 2017 accepte
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A phase I trial of beta-all-trans-retinoic acid delivered via a collagen sponge and a cervical cap for mild or moderate intraepithelial cervical neoplasia.
A phase I trial was conducted of the vitamin A derivative beta-all-trans-retinoic acid (vitamin A acid; TRA), delivered via a collagen sponge and cervical cap for mild or moderate intraepithelial cervical neoplasia. On the basis of known skin and mucosal membrane toxicity, a concentration of 0.05% TRA in a cream-based vehicle was selected as the starting dose and was escalated later with the use of a modified Fibonacchi scale. The delivery device and the TRA were changed daily for 4 days, and side effects were assessed on days 1, 2, 3, 4, 8, and 30 by clinical and colposcopic examination. Vaginal, cervical, and systemic toxicity were evaluated in 35 patients. No dose-related systemic effects were found; mild cervical inflammation increased in many patients at higher doses. Unacceptably high vaginal toxicity was reached at a TRA concentration of 0.484%. A concentration of 0.372% TRA is recommended for use in phase II trials in mild and moderate cervical intraepithelial neoplasia
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Enhancement of regression of cervical intraepithelial neoplasia II (moderate dysplasia) with topically applied all-trans-retinoic acid: a randomized trial.
BackgroundRetinoids enhance differentiation of most epithelial tissues. Epidemiologic studies have shown an inverse relationship between dietary intake or serum levels of vitamin A and the development of cervical dysplasia and/or cervical cancer. Pilot and phase I investigations demonstrated the feasibility of the local delivery of all-trans-retinoic acid (RA) to the cervix using a collagen sponge insert and cervical cap. A phase II trial produced a clinical complete response rate of 50%.PurposeThis randomized phase III trial was designed to determine whether topically applied RA reversed moderate cervical intraepithelial neoplasia (CIN) II or severe CIN.MethodsAnalyses were based on 301 women with CIN (moderate dysplasia, 151 women; severe dysplasia, 150 women), evaluated by serial colposcopy, Papanicolaou cytology, and cervical biopsy. Cervical caps with sponges containing either 1.0 mL of 0.372% beta-trans-RA or a placebo were inserted daily for 4 days when women entered the trial, and for 2 days at months 3 and 6. Patients receiving treatment and those receiving placebo were similar with respect to age, ethnicity, birth-control methods, histologic features of the endocervical biopsy specimen and koilocytotic atypia, and percentage of involvement of the cervix at study. Treatment effects were compared using Fisher's exact test and logistic regression methods. Side effects were recorded, and differences were compared using Fisher's exact test.ResultsRA increased the complete histologic regression rate of CIN II from 27% in the placebo group to 43% in the retinoic acid treatment group (P = .041). No treatment difference between the two arms was evident in the severe dysplasia group. More vaginal and vulvar side effects were seen in the patients receiving RA, but these effects were mild and reversible.ConclusionsA short course of locally applied RA can reverse CIN II, but not more advanced dysplasia, with acceptable local side effects.ImplicationsA derivative of vitamin A can reverse or suppress an epithelial preneoplasia, lending further support to the notion that chemoprevention of human cancer is feasible
The Two Faces of EU-NATO Cooperation:Counter-Piracy Operations off the Somali Coast
Maritime engagement in the Gulf of Aden is a puzzling case for anyone interested in the political and institutional problems underlying European Union–North Atlantic Treaty Organization (EU–NATO) cooperation. Although the EU’s operation NAVFOR ‘Atalanta’ and NATO’s ‘Ocean Shield’ operate in the same theatre and with similar mandates, there is no formal link between them. No joint planning has been envisaged, and no official task-sharing takes place. As this article aims to show, cooperation and coordination between EU and NATO forces at the operational and tactical levels have nevertheless worked surprisingly well. Two faces of EU–NATO cooperation become apparent: the political level is dominated by a permanent deadlock, while on the ground and at sea staff have developed a modus operandi that allows them to deliver fairly successfully in complementing yet detached operations. Based on 60 interviews with EU and NATO officials (2010–2013), this article illustrates how the operational and tactical levels have developed ways of coordinating efforts informally despite the lack of a formal framework. It aims to show to what extent and how they succeed at bypassing organizational boundaries and at overcoming political limitations. Although these practices are becoming increasingly institutionalized, it remains to be seen whether this will translate into formal changes
Estimation of colorectal adenoma recurrence with dependent censoring
<p>Abstract</p> <p>Background</p> <p>Due to early colonoscopy for some participants, interval-censored observations can be introduced into the data of a colorectal polyp prevention trial. The censoring could be dependent of risk of recurrence if the reasons of having early colonoscopy are associated with recurrence. This can complicate estimation of the recurrence rate.</p> <p>Methods</p> <p>We propose to use midpoint imputation to convert interval-censored data problems to right censored data problems. To adjust for potential dependent censoring, we use information from auxiliary variables to define risk groups to perform the weighted Kaplan-Meier estimation to the midpoint imputed data. The risk groups are defined using two risk scores derived from two working proportional hazards models with the auxiliary variables as the covariates. One is for the recurrence time and the other is for the censoring time. The method described here is explored by simulation and illustrated with an example from a colorectal polyp prevention trial.</p> <p>Results</p> <p>We first show that midpoint imputation under an assumption of independent censoring will produce an unbiased estimate of recurrence rate at the end of the trial, which is often the main interest of a colorectal polyp prevention trial, and then show in simulations that the weighted Kaplan-Meier method using the information from auxiliary variables based on the midpoint imputed data can improve efficiency in a situation with independent censoring and reduce bias in a situation with dependent censoring compared to the conventional methods, while estimating the recurrence rate at the end of the trial.</p> <p>Conclusion</p> <p>The research in this paper uses midpoint imputation to handle interval-censored observations and then uses the information from auxiliary variables to adjust for dependent censoring by incorporating them into the weighted Kaplan-Meier estimation. This approach can handle a situation with multiple auxiliary variables by deriving two risk scores from two working PH models. Although the idea of this approach might appear simple, the results do show that the weighted Kaplan-Meier approach can gain efficiency and reduce bias due to dependent censoring.</p
Security governance and networks: New theoretical perspectives in transatlantic security
The end of the Cold War has not only witnessed the rise of new transnational threats such as terrorism, crime, proliferation and civil war; it has also seen the growing role of non-state actors in the provision of security in Europe and North America. Two concepts in particular have been used to describe these transformations: security governance and networks. However, the differences and potential theoretical utility of these
two concepts for the study of contemporary security have so far been under-examined. This article seeks to address this gap. It proposes that security governance can help to explain the transformation of Cold War security structures, whereas network analysis is particularly useful for understanding the relations and interactions between public and private actors in the making and implementation of national and international security policies
SHIFTING THE PARADIGM IN RADIATION SAFETY
The current radiation safety paradigm using the linear no-threshold (LNT) model is based on the premise that even the smallest amount of radiation may cause mutations increasing the risk of cancer. Autopsy studies have shown that the presence of cancer cells is not a decisive factor in the occurrence of clinical cancer. On the other hand, suppression of immune system more than doubles the cancer risk in organ transplant patients, indicating its key role in keeping occult cancers in check. Low dose radiation (LDR) elevates immune response, and so it may reduce rather than increase the risk of cancer. LNT model pays exclusive attention to DNA damage, which is not a decisive factor, and completely ignores immune system response, which is an important factor, and so is not scientifically justifiable. By not recognizing the importance of the immune system in cancer, and not exploring exercise intervention, the current paradigm may have missed an opportunity to reduce cancer deaths among atomic bomb survivors. Increased antioxidants from LDR may reduce aging-related non-cancer diseases since oxidative damage is implicated in these. A paradigm shift is warranted to reduce further casualties, reduce fear of LDR, and enable investigation of potential beneficial applications of LDR
Cancer chemoprevention: lessons learned and future directions
The concept of delaying or preventing epithelial transformation remains a viable and attainable goal for the future. Drug-based strategies for chemoprevention of the future may predominantly rely upon targeted therapies with tolerable but defined toxicities for treatment of individuals diagnosed with intraepithelial neoplasias. Foods, diet manipulation strategies, or nutraceuticals may be more appropriate to delay or prevent carcinogenesis progression in healthy populations with genetic or epidemiologic evidence of risk for future transformation
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