Co-registration of Sequential Multidetector Computed Tomography Studies for the Evaluation of Surgical Instrumentation following Resection of Spinal Tumors

Surgical resection of spinal tumors involves complex reconstructive procedures. The stability and integrity of the surgical construct are evaluated with multidetector computed tomography (MDCT). As coregistration, or fusion, of different imaging modalities, especially positron emission tomography/computed tomography (PET/CT), is common practice, we sought to determine if this technique could be applied to sequential, postoperative MDCT studies of the spine. Herein, we demonstrate that by utilizing the Hermes workstation, co-registration of MDCT spine studies can be performed. This technique allows sequential MDCT examinations of the post-operative spine to be viewed together as one study and may aid in evaluation of the position and integrity of the surgical construct over time. Further study and refinement of this technique will be necessary before clinical implementation

Am I in the right place? : Academic engagement and study success during the first years at university

Entrance to university does not automatically lead to high academic engagement and success, and there may be individual differences in student engagement. In the present study, university students' (N = 668) academic engagement and disengagement profiles, and the differences between them in terms of academic achievement, were investigated. Students from introductory courses were classified by Latent Profile Analysis (LPA) into homogenous groups having similar patterns according to the following variables: study engagement, study-related exhaustion, lack of interest, lack of self-regulation, and uncertainty of one's career choice. Four groups of students were identified: engaged, disengaged, undecided, and alienated. Engaged students received the highest grades, with disengaged and undecided students performing most poorly. In addition, the profiles were related to the behavioral indicators of engagement (i.e., ECTS credits). Even after two years of studying, engaged students were performing better than disengaged students. The study's implications for both research and practice are discussed. (C) 2016 Elsevier Inc. All rights reserved.Peer reviewe

Decision-Directed Channel Estimation Implementation for Spectral Efficiency Improvement in Mobile MIMO-OFDM

Channel estimation algorithms and their implementations for mobile receivers are considered in this paper. The 3GPP long term evolution (LTE) based pilot structure is used as a benchmark in a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) receiver. The decision directed (DD) space alternating generalized expectation-maximization (SAGE) algorithm is used to improve the performance from that of the pilot symbol based least-squares (LS) channel estimator. The performance is improved with high user velocities, where the pilot symbol density is not sufficient. Minimum mean square error (MMSE) filtering is also used in estimating the channel in between pilot symbols. The pilot overhead can be reduced to a third of the LTE pilot overhead with DD channel estimation, obtaining a ten percent increase in data throughput. Complexity reduction and latency issues are considered in the architecture design. The pilot based LS, MMSE and the SAGE channel estimators are implemented with a high level synthesis tool, synthesized with the UMC 0.18 μm CMOS technology and the performance-complexity trade-offs are studied. The MMSE estimator improves the performance from the simple LS estimator with LTE pilot structure and has low power consumption. The SAGE estimator has high power consumption but can be used with reduced pilot density to increase the data rate.National Science FoundationTekesElektrobitRenesas Mobile EuropeAcademy of FinlandNokia Siemens NetworksXilin

Stereoscopic Visualization of Diffusion Tensor Imaging Data: A Comparative Survey of Visualization Techniques

Diffusion tensor imaging (DTI) data has traditionally been displayed as a grayscale functional anisotropy map (GSFM) or color coded orientation map (CCOM). These methods use black and white or color with intensity values to map the complex multidimensional DTI data to a two-dimensional image. Alternative visualization techniques, such as V (max) maps utilize enhanced graphical representation of the principal eigenvector by means of a headless arrow on regular nonstereoscopic (VM) or stereoscopic display (VMS). A survey of clinical utility of patients with intracranial neoplasms was carried out by 8 neuroradiologists using traditional and nontraditional methods of DTI display. Pairwise comparison studies of 5 intracranial neoplasms were performed with a structured questionnaire comparing GSFM, CCOM, VM, and VMS. Six of 8 neuroradiologists favored V (max) maps over traditional methods of display (GSFM and CCOM). When comparing the stereoscopic (VMS) and the non-stereoscopic (VM) modes, 4 favored VMS, 2 favored VM, and 2 had no preference. In conclusion, processing and visualizing DTI data stereoscopically is technically feasible. An initial survey of users indicated that V (max) based display methodology with or without stereoscopic visualization seems to be preferred over traditional methods to display DTI data

Dynamic Contrast-Enhanced Perfusion Processing for Neuroradiologists: Model-Dependent Analysis May Not Be Necessary for Determining Recurrent High-Grade Glioma versus Treatment Effect

ABSTRACT BACKGROUND AND PURPOSE: Dynamic contrast-enhanced perfusion MR imaging has proved useful in determining whether a contrastenhancing lesion is secondary to recurrent glial tumor or is treatment-related. In this article, we explore the best method for dynamic contrast-enhanced data analysis

Primely generated refinement monoids

We extend both Dobbertin's characterization of primely generated regular refinement monoids and Pierce's characterization of primitive monoids to general primely generated refinement monoids.The first-named author was partially supported by DGI MINECO MTM2011-28992-C02-01, by FEDER UNAB10-4E-378 "Una manera de hacer Europa", and by the Comissionat per Universitats i Recerca de la Generalitat de Catalunya. The second-named author was partially supported by the DGI and European Regional Development Fund, jointly, through Project MTM2011-28992-C02-02, and by PAI III grants FQM-298 and P11-FQM-7156 of the Junta de Andalucía

Risk factors for major adverse cardiovascular events after the first acute coronary syndrome

AimsTo evaluate risk factors for major adverse cardiac event (MACE) after the first acute coronary syndrome (ACS) and to examine the prevalence of risk factors in post-ACS patients.MethodsWe used Finnish population-based myocardial infarction register, FINAMI, data from years 1993-2011 to identify survivors of first ACS (n = 12686), who were then followed up for recurrent events and all-cause mortality for three years. Finnish FINRISK risk factor surveys were used to determine the prevalence of risk factors (smoking, hyperlipidaemia, diabetes and blood pressure) in post-ACS patients (n = 199).ResultsOf the first ACS survivors, 48.4% had MACE within three years of their primary event, 17.0% were fatal. Diabetes (p = 4.4 x 10(-7)), heart failure (HF) during the first ACS attack hospitalization (p = 6.8 x 10(-15)), higher Charlson index (p = 1.56 x 10(-19)) and older age (p = .026) were associated with elevated risk for MACE in the three-year follow-up, and revascularization (p = .0036) was associated with reduced risk. Risk factor analyses showed that 23% of ACS survivors continued smoking and cholesterol levels were still high (>5mmol/l) in 24% although 86% of the patients were taking lipid lowering medication.ConclusionDiabetes, higher Charlson index and HF are the most important risk factors of MACE after the first ACS. Cardiovascular risk factor levels were still high among survivors of first ACS

Epigenetic regulation of caloric restriction in aging

The molecular mechanisms of aging are the subject of much research and have facilitated potential interventions to delay aging and aging-related degenerative diseases in humans. The aging process is frequently affected by environmental factors, and caloric restriction is by far the most effective and established environmental manipulation for extending lifespan in various animal models. However, the precise mechanisms by which caloric restriction affects lifespan are still not clear. Epigenetic mechanisms have recently been recognized as major contributors to nutrition-related longevity and aging control. Two primary epigenetic codes, DNA methylation and histone modification, are believed to dynamically influence chromatin structure, resulting in expression changes of relevant genes. In this review, we assess the current advances in epigenetic regulation in response to caloric restriction and how this affects cellular senescence, aging and potential extension of a healthy lifespan in humans. Enhanced understanding of the important role of epigenetics in the control of the aging process through caloric restriction may lead to clinical advances in the prevention and therapy of human aging-associated diseases