2,779 research outputs found
Taurine change in visual cortex of neonatal monocular enucleated rat: a proton MRS study
Posters - MRS of Animal Brain: 4530Neonatal monocular enucleation has been used to study developmental mechanisms underlying visual perception and the cross-modal changes in the central nervous system caused by early loss of the visual input. In this study, we demonstrated that alteration in the metabolism of taurine in visual cortex accompanied with neonatal monocular enucleation could be monitored using 1H MRS at 7 T. The change in taurine signal with respect to creatine signal may possibly due to the increased taurine signal in the right control visual cortex, likely caused by the plasticity resulted from recruitment of resources to the remaining left eye for adaptation.postprin
In vivo assessment of hepatic ischemia/reperfusion injury in rat using diffusion tensor imaging
Session 12: Advances in Hepatobiliary Imaging - Oral presentationHepatic ischemia/reperfusion injury (IRI) occurs during liver transplantation, tumor resection, hemorrhagic shock and veno-occlusive disease, and is a major cause of acute liver failure. IRI in liver is also responsible for early organ failure and increased incidence of both acute and chronic rejection after liver transplantation. This study aims to examine the changes of diffusion measurements by diffusion tensor imaging (DTI). The experimental results demonstrated that DTI is useful in identifying hepatic IRI by characterizing the transient changes in mean diffusivity and fractional anisotropy.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 11
What Can Information Encapsulation Tell Us About Emotional Rationality?
What can features of cognitive architecture, e.g. the information encapsulation of certain emotion processing systems, tell us about emotional rationality? de Sousa proposes the following hypothesis: “the role of emotions is to supply the insufficiency of reason by imitating the encapsulation of perceptual modes” (de Sousa 1987: 195). Very roughly, emotion processing can sometimes occur in a way that is insensitive to what an agent already knows, and such processing can assist reasoning by restricting the response-options she considers. This paper aims to provide an exposition and assessment of de Sousa’s hypothesis. I argue information encapsulation is not essential to emotion-driven reasoning, as emotions can determine the relevance of response-options even without being encapsulated. However, I argue encapsulation can still play a role in assisting reasoning by restricting response-options more efficiently, and in a way that ensures which options emotions deem relevant are not overridden by what the agent knows. I end by briefly explaining why this very feature also helps explain how emotions can, on occasion, hinder reasoning
Two-Way Minimization: A Novel Treatment Allocation Method for Small Trials
Randomization is a hallmark of clinical trials. If a trial entails very few subjects and has many prognostic factors (or many factor levels) to be balanced, minimization is a more efficient method to achieve balance than a simple randomization. We propose a novel minimization method, the ‘two-way minimization’. The method separately calculates the ‘imbalance in the total numbers of subjects’ and the ‘imbalance in the distributions of prognostic factors’. And then to allocate a subject, it chooses—by probability—to minimize either one of these two aspects of imbalances. As such, it is a method that is both treatment-adaptive and covariate-adaptive. We perform Monte-Carlo simulations to examine its statistical properties. The two-way minimization (with proper regression adjustment of the force-balanced prognostic factors) has the correct type I error rates. It also produces point estimates that are unbiased and variance estimates that are accurate. When there are important prognostic factors to be balanced in the study, the method achieves the highest power and the smallest variance among randomization methods that are resistant to selection bias. The allocation can be done in real time and the subsequent data analysis is straightforward. The two-way minimization is recommended to balance prognostic factors in small trials
Adaptive design methods in clinical trials – a review
In recent years, the use of adaptive design methods in clinical research and development based on accrued data has become very popular due to its flexibility and efficiency. Based on adaptations applied, adaptive designs can be classified into three categories: prospective, concurrent (ad hoc), and retrospective adaptive designs. An adaptive design allows modifications made to trial and/or statistical procedures of ongoing clinical trials. However, it is a concern that the actual patient population after the adaptations could deviate from the originally target patient population and consequently the overall type I error (to erroneously claim efficacy for an infective drug) rate may not be controlled. In addition, major adaptations of trial and/or statistical procedures of on-going trials may result in a totally different trial that is unable to address the scientific/medical questions the trial intends to answer. In this article, several commonly considered adaptive designs in clinical trials are reviewed. Impacts of ad hoc adaptations (protocol amendments), challenges in by design (prospective) adaptations, and obstacles of retrospective adaptations are described. Strategies for the use of adaptive design in clinical development of rare diseases are discussed. Some examples concerning the development of Velcade intended for multiple myeloma and non-Hodgkin's lymphoma are given. Practical issues that are commonly encountered when implementing adaptive design methods in clinical trials are also discussed
Characterization of myocardial T1 and partition coefficient as a function of time after gadolinium delivery in healthy subjects
Constructal design for pedestrian movement in living spaces : evacuation configurations
Author name used in this publication: C. H. LuiAuthor name used in this publication: N. K. FongAuthor name used in this publication: S. LorentAuthor name used in this publication: A. BejanAuthor name used in this publication: W. K. Chow2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
A review of plant-flow interactions on salt marshes: the importance of vegetation structure and plant mechanical characteristics
Observations of plant-flow interactions on salt marshes have revealed a highly complex process dominated by the tightly coupled effects of plant characteristics and hydrodynamic conditions. This paper highlights the importance of vegetation structures such as plant density and height, as well as their spatial variability and mechanical properties including flexibility, upon energy dissipation and flow modification. Many field, laboratory and modelling studies which attempt to predict flow dissipation or improve our understanding of plant-flow interactions use simplified structural measures of salt marsh vegetation or artificial representations. These simplifications neglect important plant and canopy elements and are unlikely to be truly representative of their natural counterparts. Such approaches limit our understanding of plant-flow interactions and potentially compromise the predictive accuracy and application of numerical flow models. It is important therefore that improved techniques to measure vegetation structure are adopted in order to better define the key relationships between measurable plant characteristics and drag-relevant plant properties.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/wat2.110
Risk of adenocarcinomas of the oesophagus and gastric cardia in patients hospitalized for asthma
In the first cohort study of the question we followed 92 986 (42 663 men and 50 323 women) adult patients hospitalized for asthma in Sweden from 1965 to 1994 for an average of 8.5 years to evaluate their risk of oesophageal and gastric cardia adenocarcinoma. Standardized incidence ratio (SIR) adjusted for gender, age and calendar year was used to estimate relative risk, using the Swedish nationwide cancer incidence rates as reference. Asthmatic patients overall had a moderately elevated risk for oesophageal adenocarcinoma (SIR = 1.5, 95% confidence interval CI, 0.9–2.5) and gastric cardia cancer (SIR = 1.4, 95% CI, 1.0–1.9). However, the excess risks were largely confined to asthmatic patients who also had a discharge record of gastro-oesophageal reflux (SIR = 7.5, 95% CI, 1.6–22.0 and SIR = 7.1, 95% CI, 3.1–14.0, respectively). No significant excess risk for oesophageal squamous-cell carcinoma or distal stomach cancer was observed. In conclusion, asthma is associated with a moderately elevated risk of developing oesophageal or gastric cardia adenocarcinoma. Special clinical vigilance vis-à-vis gastro-esophageal cancers seems unwarranted in asthmatic patients, but may be appropriate in those with clinically manifest gastro-oesophageal reflux. http://www.bjcancer.com © 2001 Cancer Research Campaig
Objective effect manifestation of pectus excavatum on load-stressed pulmonary function testing: a case report
Abstract Introduction Pectus excavatum is the most common congenital deformity of the anterior chest wall that, under certain conditions, may pose functional problems due to cardiopulmonary compromise and exercise intolerance. Case presentation We present the case of an otherwise physically-adept 21-year-old Chinese sportsman with idiopathic pectus excavatum, whose symptoms manifested only on bearing a loaded body vest and backpack during physical exercise. Corroborative objective evidence was obtained via load-stressed pulmonary function testing, which demonstrated restrictive lung function. Conclusion This report highlights the possible detrimental synergism of thoracic load stress and pectus excavatum on cardiopulmonary function. Thoracic load-stressed pulmonary function testing provides objective evidence in support of such a synergistic relationship.</p
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