Resolution improvement of brain PET images using prior information from MRI: clinical application on refractory epilepsy

An important counterpart of clinical Positron Emission Tomography (PET) for early diagnosis of neurological diseases is its low resolution. This is particularly important when evaluating diseases related to small hypometabolisms such as epilepsy. The last years, new hybrid systems combining PET with Magnetic Resonance (MR) has been increasingly used for several different clinical applications. One of the advantages of MR is the production of high spatial resolution images and a potential application of PET-MR imaging is the improvement of PET resolution using MR information. A potential advantage of resolution recovery of PET images is the enhancement of contrast delivering at the same time better detectability of small lesions or hypometabolic areas and more accurate quantification over these areas. Recently, Shidahara et al (2009) proposed a new method using wavelet transforms in order to produce PET images with higher resolution. We optimised Shidahara’s method (SFS-RR) to take into account possible shortcomings on the particular clinical datasets, and applied it to a group of patients diagnosed with refractory epilepsy. FDG-PET and MRI images were acquired sequentially and then co-registered using software tools. A complete evaluation of the PET/MR images was performed before and after the correction, including different parameters related with PET quantification, such as atlas-based metabolism asymmetry coefficients and Statistical Parametric Mapping results comparing to a database of 87 healthy subjects. Furthermore, an experienced physician analyzed the results of non-corrected and corrected images in order to evaluate improvements of detectability on a visual inspection. Clinical outcome was used as a gold standard. SFS-RR demonstrated to have a positive impact on clinical diagnosis of small hypometabolisms. New lesions were detected providing additional clinically relevant information on the visual inspection. SPM sensitivity for the detection of small lesions was increased from 70% to 90%

Reflexión sobre la fundamentación teórica de la contabilidad como ciencia

Accounting and its current discourse for some researchers of the subject shouldn’t be considered a science nor theory given that the use of their conceptual bases its limited to the simple application of rules and procedures, ensuring strict compliance with international precepts which aim is to delimit their actions. Professionals on the accounting subject seem to focus their efforts to become bookkeepers exclusively, i.e., they base their commitment to the implementation of its instrumental rationality, to preserve their identification processing, measurement and communication of quantitative information status, on the search to preserve its system of financial information efficient status; we infer that this way they try to preserve their existence and permanence in life making it a way of generating income as a basis for the livelihood of their family environment. Satisfy companies in their need for accounting information, which leads to accounting to be-seem like a simple mechanical process. This essay aims to analyze the theoretical- epistemological position of science researchers, the use of elements of the natural sciences for the construction and reconstruction of the conceptual structure of the social sciences, and the discourse of the scientificity of accounting.La contabilidad y su actual discurso para algunos estudiosos del área no deben ser aun considerada ciencia ni teoría dado que la utilización de sus bases conceptuales se limita a la simple aplicación de normas y procedimientos cuidando en ellas el fiel cumplimiento de preceptos internacionales cuyo fin es delimitar su accionar. Los profesionales de la materia contable parecieran enfocar su esfuerzo a convertirse en tenedores de libros exclusivamente, es decir, basan su empeño en la aplicación de su racionalidad instrumental, en preservar su condición de proceso de identificación, medición y comunicación de información cuantitativa, en la búsqueda de conservar su eficiente condición de sistema de información financiero; inferimos que de esa manera intentan preservar su  existencia y permanencia en la vida haciendo de ello una forma de generación de ingresos como base para el sustento de su entorno familiar. Satisfacer a las empresas en su necesidad de información contable, lo que conlleva a la contabilidad a ser-parecer un simple proceso mecanicista. En este ensayo se propone anali- zar la posición teórico - epistemológica de estudiosos de las ciencias, la utilización de elementos propios de las ciencias naturales esgrimidos para la construcción y reconstrucción de la estructura conceptual de las ciencias sociales, y el discurso de la cientificidad de la contabilidad.

Iterative Structural and Functional Synergistic Resolution Recovery (iSFS-RR) Applied to PET-MR Images in Epilepsy

Structural Functional Synergistic Resolution Recovery (SFS-RR) is a technique that uses supplementary structural information from MR or CT to improve the spatial resolution of PET or SPECT images. This wavelet-based method may have a potential impact on the clinical decision-making of brain focal disorders such as refractory epilepsy, since it can produce images with better quantitative accuracy and enhanced detectability. In this work, a method for the iterative application of SFS-RR (iSFS-RR) was firstly developed and optimized in terms of convergence and input voxel size, and the corrected images were used for the diagnosis of 18 patients with refractory epilepsy. To this end, PET/MR images were clinically evaluated through visual inspection, atlas-based asymmetry indices (AIs) and SPM (Statistical Parametric Mapping) analysis, using uncorrected images and images corrected with SFS-RR and iSFS-RR. Our results showed that the sensitivity can be increased from 78% for uncorrected images, to 84% for SFS-RR and 94% for the proposed iSFS-RR. Thus, the proposed methodology has demonstrated the potential to improve the management of refractory epilepsy patients in the clinical routine

Modeling elastic and photoassisted transport in organic molecular wires: length dependence and current-voltage characteristics

Using a pi-orbital tight-binding model, we study the elastic and photoassisted transport properties of metal-molecule-metal junctions based on oligophenylenes of varying lengths. The effect of monochromatic light is modeled with an ac voltage over the contact. We first show how the low-bias transmission function can be obtained analytically, using methods previously employed for simpler chain models. In particular, the decay coefficient of the off-resonant transmission is extracted by considering both a finite-length chain and infinitely extended polyphenylene. Based on these analytical results, we discuss the length-dependence of the linear-response conductance, the thermopower, and the light-induced enhancement of the conductance in the limit of weak intensity and low frequency. In general the conductance-enhancement is calculated numerically as a function of the light frequency. Finally, we compute the current-voltage characteristics at finite dc voltages, and show that in the low-voltage regime, the effect of low-frequency light is to induce current steps with a voltage separation determined by twice the frequency. These effects are more pronounced for longer molecules. We study two different profiles for the dc and ac voltages, and it is found that the results are robust with respect to such variations. Although we concentrate here on the specific model of oligophenylenes, the results should be qualitatively similar for many other organic molecules with a large enough electronic gap.Comment: 15 pages, 11 figures, minor corrections to old versio

Construcción y estandarización de pruebas de aptitud y de conocimientos utilizables en orientación profesional

La orientación profesional es necesaria para los bachilleres colombianos. En las circunstancias actuales de desarrollo y de cambio nuestro país manifiesta una problemática de aspiraciones y necesidades quizás más compleja, por falta de límites precisos, que la de otros países.EI bachiller, al elegir la manera como va a servir a la colectividad mediante una práctica profesional, se enfrenta a una situación conflictiva. De una parte ignora que necesidad tiene el país de la profesión que desea seguir; como se adecuan sus capacidades a las exigencias de ella y, en su ejercicio, satisfará las aspiraciones personales. De otra parte debe elegir y... elige con indecisión

Organic phase separation opens up new opportunities to interrogate the RNA-binding proteome.

Protein-RNA interactions regulate all aspects of RNA metabolism and are crucial to the function of catalytic ribonucleoproteins. Until recently, the available technologies to capture RNA-bound proteins have been biased toward poly(A) RNA-binding proteins (RBPs) or involve molecular labeling, limiting their application. With the advent of organic-aqueous phase separation-based methods, we now have technologies that efficiently enrich the complete suite of RBPs and enable quantification of RBP dynamics. These flexible approaches to study RBPs and their bound RNA open up new research avenues for systems-level interrogation of protein-RNA interactions

A nipple shield delivery system for oral drug delivery to breastfeeding infants : Microbicide delivery to inactivate HIV

A new drug delivery method for infants is presented which incorporates an active pharmaceutical ingredient (API)-loaded insert into a nipple shield delivery system (NSDS). The API is released directly into milk during breastfeeding. This study investigates the feasibility of using the NSDS to deliver the microbicide sodium dodecyl sulfate (SDS), with the goal of preventing mother-to-child transmission (MTCT) of HIV during breastfeeding in low-resource settings, when there is no safer alternative for the infant but to breastfeed. SDS has been previously shown to effectively inactivate HIV in human milk. An apparatus was developed to simulate milk flow through and drug release from a NSDS. Using this apparatus milk was pulsed through a prototype device containing a non-woven fiber insert impregnated with SDS and the microbicide was rapidly released. The total SDS release from inserts ranged from 70 to 100% of the average 0.07 g load within 50 ml (the volume of a typical breastfeed). Human milk spiked with H9/HIVIIIB cells was also passed through the same set-up. Greater than 99% reduction of cell-associated HIV infectivity was achieved in the first 10 ml of milk. This proof of concept study demonstrates efficient drug delivery to breastfeeding infants is achievable using the NSDS

Galactic ArchaeoLogIcaL ExcavatiOns (GALILEO) II. t-SNE Portrait of Local Fossil Relics and Structures

Based on high-quality APOGEE DR17 and Gaia DR3 data for 1,742 red giants stars within 5 kpc of the Sun and not rotating with the Galactic disc ($V_\phi <$ 100 km s$^{-1}$), we use the nonlinear technique of unsupervised analysis t-SNE to detect coherent structures in the space of ten chemical-abundance ratios: [Fe/H], [O/Fe], [Mg/Fe], [Si/Fe], [Ca/Fe], [C/Fe], [N/Fe], [Al/Fe], [Mn/Fe], and [Ni/Fe]. Additionally, we obtain orbital parameters for each star using the non-axisymmetric gravitational potential {\tt GravPot16}. Seven structures are detected, including the Splash, Gaia-Sausage-Enceladus (GSE), the high-$\alpha$ heated-disc population, N-C-O peculiar stars, and inner disk-like stars, plus two other groups that did not match anything previously reported in the literature, here named Galileo 5 and Galileo 6 (G5 and G6). These two groups overlap with Splash in [Fe/H], G5 being lower metallicity than G6, both between GSE and Splash in the [Mg/Mn] versus [Al/Fe] plane, G5 in the $\alpha$-rich in-situ locus, and G6 on the border of the $\alpha$-poor in-situ one; nonetheless their low [Ni/Fe] hints to a possible ex-situ origin. Their orbital energy distributions are between the Splash and GSE, with G5 being slightly more energetic than G6. We verified the robustness of all the obtained groups by exploring a large range of t-SNE parameters, applying it to various subsets of data, and also measuring the effect of abundance errors through Monte Carlo tests.Comment: Accepted by A&A. 19 pages, 15 figures, and 3 table

Análisis comparado en materia de obligaciones entre el derecho romano y el derecho moderno

This paper presents a study of ancient and modern concepts of “obligation,” with special reference to Roman law, as well as sources and classifications of the same. Likewise, the influence of Roman law on the Venezuelan Civil Code is analyzed in matters regarding obligations. In this sense, the Roman definition has predominated in modern law; even today it can be affirmed that it has remained unharmed within its fundamental concepts. The method used is descriptive and documentary. Conclusions are that definitions of obligations in modern law are limited to reproducing the Roman-inspired principles and that our Civil Code received a strong influence from the Franco-Italian Project of Obligations, in which the concepts and effects of certain figures that produced obligations were developed.Se realiza un estudio dogmático de los conceptos antiguo y moderno de la "obligación", con especial referencia al Derecho romano, así como a las fuentes y clasificación de las mismas. Del mismo modo, se analiza la influencia del derecho romano en el Código civil venezolano, en materia de obligaciones. En este sentido, la definición romana ha predominado en el Derecho Moderno, incluso en la actualidad se puede afirmar que ha permanecido incólume dentro sus concepciones fundamentales. El método utilizado es el descriptivo y documental. Se concluye que las definiciones de las obligaciones en el Derecho Moderno se limitan a reproducir los principios inspiradores romanos y que nuestro Código civil recibió una fuerte influencia del Proyecto Franco-Italiano de las Obligaciones, en el cual se desarrolló el concepto y los efectos de determinadas figuras productoras de obligacione