143 research outputs found
The spectrum of imaging findings in pulmonary hydatid disease and the additive value of T2-weighted magnetic resonance imaging in its diagnosis
Purpose: To describe the spectrum of imaging findings in pulmonary echinococcosis and to study the additive value of T2-weighted magnetic resonance imaging (MRI) in the characterisation of pulmonary hydatid disease. Material and methods: This was a descriptive, prospective study conducted for a period of 3 years from December 2016 to November 2019. Patients suspected of having pulmonary echinococcosis (n = 110) on preliminary chest radiography were examined with chest computed tomography (CT). Among them 41 cases were additionally examined with T2-weighted MRI of thorax. Final diagnosis was based on surgery or histopathology. Results: Of the 110 patients enrolled for the study 15 were lost to attrition, and among the final cohort of 95 patients CT correctly diagnosed 68/84 (80.9%) as hydatid cyst, whereas 16/84 (19.1%) received an erroneous alternate diagnosis on CT. Based on the classical findings of hyperintense pulmonary cystic lesion with T2-weighted hypointense rim or detached internal T2-weighted hypointense membrane, a correct diagnosis of hydatid cyst was possible in 30 patients whereas a correct alternate diagnosis was made in 8 cases. T2-weighted MRI was found to have sensitivity of 96.7%, specificity of 80%, positive predictive value (PPV) of 93.7% and negative predictive value (NPV) of 88.9% with an overall diagnostic accuracy of 92.6%. Using the McNemar test, MRI was found to be diagnostically superior to CT (p = 0.019). Conclusions: Most of the pulmonary hydatid cysts can be diagnosed on CT; however, sometimes the findings may be indeterminate or atypical, leading to a diagnostic dilemma. MRI, owing to its ability to demonstrate hypointense endocyst, can act as a useful adjunct to correctly diagnose hydatid cyst or suggest an alternative diagnosis
An alkali catalyzed trans-esterification of rice bran, cottonseed and waste cooking oil
In this research work, biodiesel production by trans-esterification of three
raw materials including virgin and used edible oil and non edible oil has
been presented. A two step method following acidic and alkali catalyst was
used for non edible oil due to the unsuitability of using the straight
alkaline-catalyzed trans-esterification of high FFA present in rice bran
oil. The acid value after processing for rice bran, cottonseed and waste
cooking oil was found to be 0.95, 0.12 and 0.87 respectively. The influence
of three variables on percentage yield i.e., methanol to oil molar ratio,
reaction temperature and reaction time were studied at this stage.
Cottonseed oil, waste cooking oil and rice bran oil showed a maximum yield
of 91.7%, 84.1% and 87.1% under optimum conditions. Fuel properties of the
three biodiesel satisfied standard biodiesel fuel results
Conditional linearizability criteria for a system of third-order ordinary differential equations
We provide linearizability criteria for a class of systems of third-order
ordinary differential equations (ODEs) that is cubically semi-linear in the
first derivative, by differentiating a system of second-order quadratically
semi-linear ODEs and using the original system to replace the second
derivative. The procedure developed splits into two cases, those where the
coefficients are constant and those where they are variables. Both cases are
discussed and examples given
Lie and Noether symmetries of geodesic equations and collineations
The Lie symmetries of the geodesic equations in a Riemannian space are
computed in terms of the special projective group and its degenerates (affine
vectors, homothetic vector and Killing vectors) of the metric. The Noether
symmetries of the same equations are given in terms of the homothetic and the
Killing vectors of the metric. It is shown that the geodesic equations in a
Riemannian space admit three linear first integrals and two quadratic first
integrals. We apply the results in the case of Einstein spaces, the
Schwarzschild spacetime and the Friedman Robertson Walker spacetime. In each
case the Lie and the Noether symmetries are computed explicitly together with
the corresponding linear and quadratic first integrals.Comment: 19 page
Energy Content of Colliding Plane Waves using Approximate Noether Symmetries
This paper is devoted to study the energy content of colliding plane waves
using approximate Noether symmetries. For this purpose, we use approximate Lie
symmetry method of Lagrangian for differential equations. We formulate the
first-order perturbed Lagrangian for colliding plane electromagnetic and
gravitational waves. It is shown that in both cases, there does not existComment: 18 pages, accepted for publication in Brazilian J Physic
The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brain–behavior relationships after stroke
The goal of the Enhancing Neuroimaging Genetics through Meta‐Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well‐powered meta‐ and mega‐analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and large‐scale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided
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