55 research outputs found
Accidental intralenticular dexamethasone intravitreal implant with the resolution of macular oedema in central retinal vein occlusion
No abstract availabl
X-ray phase contrast microscopy at 300 nm resolution with laboratory sources.
We report the performance of an X-ray phase contrast microscope for laboratory sources with 300 nm spatial resolution. The microscope is based on a commercial X-ray microfocus source equipped with a planar X-ray waveguide able to produce a sub-micrometer x-ray beam in one dimension. Phase contrast images of representative samples are reported. The achieved contrast and resolution is discussed for different configurations. The proposed approach could represent a simple, inexpensive, solution for sub-micrometer resolution imaging with small laboratory setups
Retinal Tectonics after Macular Pucker Surgery: Thickness Changes and En-Face Displacement Recovery.
PURPOSE
To study visual function, retinal layer thickness changes and tangential displacement after Pars Plana Vitrectomy (PPV) for EpiRetinal Membrane (ERM).
METHODS
Retrospective series of patients undergoing PPV for ERM, with 6-month follow-up including best-corrected visual acuity (BCVA), Optical Coherence Tomography (OCT), M-charts, ERM grading, and InfraRed fundus photo at time 0 (T0, pre-op) at month 1 (T1), 3 (T3), 6 (T6) post-op (±1 week). Retinal layer thickness and tangential (en-face) retinal displacement between successive times for the entire retinal surface and the central horizontal and vertical meridian were also measured. En-face displacement was calculated as optical flow of consecutive images.
RESULTS
Average BCVA improved from 0.28±0.08 logMAR at T0 to 0.16±0.25 at T6 (p=0.05), BCVA improvement correlated with BVCA at T0 (p<0.001). Vertical metamorphopsia decreased from 1.33°±0.70° at T0 to 0.82°±0.69° at T6 (p<0.05). Foveal thickness reduced from 453±53”m at T0 to 359±31”m at T6 (p<0.05) and reduction correlated with BCVA improvement (p<0.05). Foveal layers decreased (p<0.05) in all cases. Mean en-face deformation was 155.82±50.17”m and mostly occurred in the first month: T0-T1 displacement was 83.59±30.28”m, T1-T3 was 36.28±14.45”m, while T3-T6 was 39.11±22.79”m (p<0.001) on average. Peri-foveal and parafoveal deformation correlated with OCT foveal thickness reduction at all time intervals (1, 3, 6 months: p<0.01).
CONCLUSION
ERM peeling affects all retinal layer thickness and results in new force balance across the entire retina and tangential displacement. Both en-face and in-depth changes correlate with visual function
Dosimetry optimization system and integrated software (DOSIS) : a comparison against Fluka code results over a standard phantom
Trabajo presentado en el X Latin American Symposium on Nuclear Physics and Applications (X LASNPA), 1-6 diciembre 2013. Montevideo, Uruguay.Actually, dual-imaging facilities allow obtainance of both mass and activity patient-specific distributions perfectly correlated, which are important to improve dose distributions estimations and radioimmunotherapy treatment planifications accuracy. Calculus methods at voxel level require both quantitative and qualitative validation to obtain improvements in patient-specific dosimetry. The present work presents advances on the development of a novel computational tool dedicated to 3D patient-specific dosimetry at voxel level; and its results analysis and visualization. With the aim of providing a dosimetric tool for planar and tridimensional methods at voxel level, as well as the development of a platform based on fullstochastic methods for α-, ÎČ- and Îł-emitters used in radiopharmaceutical applications. DOSIS is based on the Boltzmann radiation transport equation to realize energy delivering calculations. Procedures for 2D and 3D dosimetry have been designed tacking into accont established formalism and standards on MIRD Pamphlets. Anatomic and metabolic images, and dose maps resulting of this calculus are analysed and procesed by a special developed and designed software. DOSIS has been preliminary validated on some standard clinic cases in comparison whith other standard procedures used commonly in radionuclide treatments, showing great accordance on its results and a friendly user usability. Finally, a dose calculation over a standard phantom is performed using DOSIS calculation code and FLUKA, validating the radiation transport code of DOSIS.publishedVersionFil: PĂ©rez, Pedro Antonio. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: PĂ©rez, Pedro Antonio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: PĂ©rez, Pedro Antonio. Universidad Nacional de CĂłrdoba. Laboratorio de InvestigaciĂłn e InstrumentaciĂłn en FĂsica Aplicada a la Medicina e ImĂĄgenes por Rayos X; Argentina.Fil: PĂ©rez, Pedro Antonio. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FĂsico-QuĂmicas y Naturales. Departamento de FĂsica; Argentina.Fil: Botta, Francesca. European Institute of Oncology; Italia.Fil: Cremonesi, Marta. European Institute of Oncology; Italia.Fil: Ferrari, Mahila. European Institute of Oncology; Italia.Fil: Guerriero, Francesco. European Institute of Oncology; Italia.Fil: Malano, Francisco Mauricio. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Malano, Francisco Mauricio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Malano, Francisco Mauricio. Universidad Nacional de CĂłrdoba. Laboratorio de InvestigaciĂłn e InstrumentaciĂłn en FĂsica Aplicada a la Medicina e ImĂĄgenes por Rayos X; Argentina.Fil: Pedroli, Guido. European Institute of Oncology; Italia.Fil: Scarinci, Ignacio Emanuel. Universidad Nacional de CĂłrdoba. Laboratorio de InvestigaciĂłn e InstrumentaciĂłn en FĂsica Aplicada a la Medicina e ImĂĄgenes por Rayos X; Argentina.Fil: Valente, Mauro AndrĂ©s. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂa y FĂsica; Argentina.Fil: Valente, Mauro AndrĂ©s. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de FĂsica Enrique Gaviola; Argentina.Fil: Valente, Mauro AndrĂ©s. Universidad Nacional de CĂłrdoba. Laboratorio de InvestigaciĂłn e InstrumentaciĂłn en FĂsica Aplicada a la Medicina e ImĂĄgenes por Rayos X; Argentina.FĂsica AtĂłmica, Molecular y QuĂmica (fĂsica de ĂĄtomos y molĂ©culas incluyendo colisiĂłn, interacciĂłn con radiaciĂłn, resonancia magnĂ©tica, Moessbauer Efecto.
Recognizing the Diverse Roles of Community Health Workers in the Elimination of Health Disparities: From Paid Staff to Volunteers
Abstract The community health worker (CHW) model has been successfully used to promote health and reduce adverse health outcomes in under-served communities. Although there is a general consensus that involvement of natural helpers from the targeted communities is a promising approach in the elimination of health disparities, there is less agreement on their responsibilities, scope of work, and reimbursement for their services (ranging from paid staff to unpaid volunteers). These differences in pay structure stem from philosophical differences, programmatic needs, and financial realities. Based on our experience with both the paid and volunteer approaches, we provide some lessons learned on how the CHW model can be integrated in our efforts to eliminate health disparities
Abdominal drainage after elective colorectal surgery: propensity score-matched retrospective analysis of an Italian cohort
background: In italy, surgeons continue to drain the abdominal cavity in more than 50 per cent of patients after colorectal resection. the aim of this study was to evaluate the impact of abdominal drain placement on early adverse events in patients undergoing elective colorectal surgery. methods: a database was retrospectively analysed through a 1:1 propensity score-matching model including 21 covariates. the primary endpoint was the postoperative duration of stay, and the secondary endpoints were surgical site infections, infectious morbidity rate defined as surgical site infections plus pulmonary infections plus urinary infections, anastomotic leakage, overall morbidity rate, major morbidity rate, reoperation and mortality rates. the results of multiple logistic regression analyses were presented as odds ratios (OR) and 95 per cent c.i. results: a total of 6157 patients were analysed to produce two well-balanced groups of 1802 patients: group (A), no abdominal drain(s) and group (B), abdominal drain(s). group a versus group B showed a significantly lower risk of postoperative duration of stay >6 days (OR 0.60; 95 per cent c.i. 0.51-0.70; P < 0.001). a mean postoperative duration of stay difference of 0.86 days was detected between groups. no difference was recorded between the two groups for all the other endpoints. conclusion: this study confirms that placement of abdominal drain(s) after elective colorectal surgery is associated with a non-clinically significant longer (0.86 days) postoperative duration of stay but has no impact on any other secondary outcomes, confirming that abdominal drains should not be used routinely in colorectal surgery
Circulating irisin levels in functional hypothalamic amenorrhea: a new bone damage index? A pilot study.
Purpose: Patients with functional hypothalamic amenorrhea (FHA) could commonly have bone damage, often preceded by metabolic alterations due to a relative energy deficit state. To date, there are no markers capable of predicting osteopenia before it is manifested on DXA. Irisin is a myokine that promotes the differentiation of osteoblastic cells and appears to be inversely correlated with the incidence of bone fragility and fractures in postmenopausal women. The aim of this study was to measure irisin levels in FHA patients and to correlate it with bone density parameters.
Methods: Thirty-two patients with FHA and 19 matched controls underwent the same clinical and laboratory evaluation.
Results: Irisin and body mass index (BMI) were significantly lower in the case group than in healthy controls (2.03 ± 0.12 vs. 2.42 ± 0.09 p < 0.05 and 19.43 ± 2.26 vs. 22.72 ± 0.67 p < 0.05, respectively). Additionally, total body mass density (BMD g/cm2) was significantly lower in the case group than in the healthy controls (1.09 ± 0.08 vs. 1.14 ± 0.05, p < 0.05), without signs of osteopenia.
Conclusions: The FHA group showed lower irisin levels associated with significantly reduced BMD parameters that did not reach the severity of osteopenia. Therefore, we could speculate that irisin could predict DXA results in assessing modifications of body composition parameters. Future research is warranted to study these parameters in a larger population to confirm our results, so that irisin could be used as a predictor and screening method for bone deprivation. Furthermore, irisin is strictly related to energy metabolism and could be an indirect marker of nutritional status in FHA patients, identifying earlier states of energy deficit.
Keywords: Amenorrhea; Body composition; Bone diseases; Energy metabolism; Osteoporosis
In Your Face! Investigating Facework, Criticism, and Humour with Corpora in Electoral Debates
In political debates, the media[tisation] can determine the use of language with the aim to increase their spectacularisation and polarisation, possibly by means of criticism and humour, respectively. These linguistic strategies are often used in order to shape what was defined by Goffman as oneâs face. Politicians, in particular, can recur to facework in a double sense: shaping their own face positively and/or that of their opponents negatively. Starting from the sociologic theory of face by Goffman and Levinson, with the help of corpus analysis tools, this research investigated the ways in which various forms of criticism and forms of humour were conducted in 3 electoral debates on a national scale (Germany, Ireland, and New Zealand) and 1 debate for the municipal election in Rome. The transcripts were revised after automatic transcriptions were extracted or found online, of which the audio-visual content is available on the Internet. The CADS research aimed to investigate the role that criticism and humour played within each participantâs discourse, and to identify differences and similarities among the strategies used by political leaders and moderators in different countries, and in different cultural, political, and media contexts
Robust Bayesian inference via optimal transport misfit measures: applications and algorithms
Model misspecification constitutes a major obstacle to reliable inference in many problems. In the Bayesian setting, model misspecification can lead to inconsistency as well as overconfidence in the posterior distribution associated with any quantity of interest, i.e., under-reporting of uncertainty.
This thesis develops a Bayesian framework to reduce the impact of a type of model misspecification arising in inference problems involving time series data: unmodeled time warping between the observed and modeled data. Inference problems involving dynamical systems, signal processing, and more generally functional data can be affected by this type of misspecification. Inverse problems in seismology are an important example of this class: inaccuracies in characterizing the complex, spatially heterogeneous propagation velocities of seismic waves can lead to error in their modeled time evolution. Data are insufficient to constrain these propagation velocities, and therefore we instead seek robustness to model error. Instrumental to our approach is the use of transportâLagrangian (TL) distances as loss/misfit functions: such distances can be understood as âgraph-spaceâ optimal transport distances, and they naturally disregard certain features of the data that are more sensitive to time warping. We show that, compared to standard misfit functions, they produce posterior distributions that are both less biased and less dispersed.
In particular, we use moment tensor inversion, a seismic inverse problem, as our primary motivating application and demonstrate improved inversion performance of the TL lossâby a variety of statistical and physical metricsâfor a range of increasingly complex inversion and misspecification scenarios. At the same time, we address several broader methodological issues. First, in the absence of a tractable expression for a TL-based likelihood, we construct a consistent prior-to-posterior update using the notion of a Gibbs posterior. We then compare the impact of different loss functions on the Gibbs posterior through a broader exploration of what constitutes âgoodâ inference in the misspecified setting, via several statistical scoring rules and rank statistics, as well as application-specific physical criteria. In an effort to link our generalized (Gibbs) Bayesian approach to a more traditional Bayesian setting, we also conduct an analytical and numerical investigation of statistical properties of the transport-Lagrangian distance between random noisy signals.
As a complement to Bayesian inversion, we also demonstrate the utility of optimal transport distances for frequentist regression. We study the linear regression model with TL loss, describe the geometry of the associated mixed-integer optimization problem, and propose dedicated algorithms that exploit its underlying structure. We then compare TL linear regression with classical linear regression in several applications.
Finally, we discuss potential generalizations of TL distances to include the notion of âshapeâ through time series embeddings, as well as possible extensions of the proposed framework to other forms of model misspecification.Ph.D
Monitoring safety during airline operations : a systems approach
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 81-83).Flight Operation Quality Assurance (FOQA) programs are today customary among major airlines. Technological progress has made it possible to monitor more than 1000 parameters per flight. Given the limited amount of resources an airline can allocate to analyze this amount of data, a need has emerged for more effective approaches to extract useful information out of FOQA programs. A new approach to flight data monitoring and analyzing is presented in this thesis, with the intent to help air carriers identify unsafe system behavior during operations. This new approach builds on two main concepts: hazard analysis based on system theory (STPA - System Theoretic Process Analysis) and hazard management through assumptions identification and leading indicators. STPA is a new hazard analysis technique that allows taking into account not only hardware failures, but also human behavior, requirement flaws, organizational aspects and non-linear component interactions. Once hazard scenarios are identified, mitigation actions are put in place to deal with these hazards, and the assumptions that lie behind these mitigation measures are made explicit. The objective is to define key parameters that allow monitoring the validity of the assumptions through the use of FOQA data. These parameters are called leading indicators. The use of the flight data monitoring approach presented in this thesis is particularly beneficial when it comes to monitoring human behavior since humans are the part of the system on which the greatest number of assumptions is made (respect of procedures, knowledge of automation, situational awareness etc.). Moreover, by linking assumptions identification to FOQA data it is possible to continuously monitor whether the mitigation measures put in place are really effective or not. In other words the loop between the design phase of a system and its operations is closed.by Andrea Scarinci.S.M
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