128 research outputs found
Mecánica del daño en fascia: caracterización experimental y análisis estadístico
El objetivo de este trabajo es ampliar la comprensión de la mecánica del daño de la fascia y sus propiedades realizando ensayos de tracción uniaxial en dirección longitudinal y transversal. Con el fin de investigar las diferencias en el comportamiento del daño, se llevó a cabo un análisis estadístico. Se compararon los valores máximos de tensión (σr) y estiramiento (λr) en ambas direcciones y las energías asociadas hasta el fallo (Wl, Wt)
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Evaluación y descripción del desarrollo del discurso narrativo en español/Evaluation and description of narrative development in Spanish
Background and objectives: The skills involved in narrative production are a good indicator of children's current language competence and predict future linguistic performance. It is important in speech and language therapy and education research to have specific assessments of developing narrative abilities. To date, however, there are few tests that assess the development of narratives in Spanish. This research has a double objective: first, to adapt the Test of Narrative Production to Spanish; and second, to describe the development of narrative skills using the adapted test. Method: A total of 146 children aged 4-11 years with Spanish as their mother tongue were evaluated by the Test of Narrative Production adapted to Spanish, and were assessed for their narrative skills at the level of both macrostructure and microstructure. Results: A strong significant correlation between age and narrative performance was observed at the macrostructural and microstructural levels. However, although both levels showed a stabilization at age 9 years, at the microstructural level cohesive devices continued developing until age 11 years. Conclusions: The test can be considered a valid evaluation of narrative development in Spanish. The results are consistent with research in English-speaking children, where it has been shown that they acquire a similar level of narrative performance to that of adults at 9 years of age at the macrostructural level, but they continue to develop and refine the microstructural level until adolescence
Clonidina en el tratamiento de la deshabituación tabáquica. Comparación con chicles de nicotina
The objective of our work was to carry out a prospective study on the effectiveness of clonidine and nicotine gum in the treatment of tobacco withdrawal. Sixty smokers were randomly distributed in two groups and were included in a tobacco withdrawal program. One group received oral clonidine treatment while the other group was given nicotine gum. Adjuvant therapy such as group therapy or psychotherapy was not performed. At the end of one year there were no significant differences between the two groups with regards to the number of subjects who have continued to stop smoking. There were also no significant differences between the two groups with regards to the symptoms of tobacco abstinence. When we studied the relation between treatment fulfillment and tobacco withdrawal we observed that the clonidine treated group had a significantly greater number of success compared to the nicotine group (p < 0.01)
A model for right-handed neutrino magnetic moments
A simple extension of the Standard Model providing Majorana magnetic moments
to right-handed neutrinos is presented. The model contains, in addition to the
Standard Model particles and right-handed neutrinos, just a singly charged
scalar and a vector-like charged fermion. The phenomenology of the model is
analysed and its implications in cosmology, astrophysics and lepton flavour
violating processes are extracted. If light enough, the charged particles
responsible for the right-handed neutrino magnetic moments could copiously be
produced at the LHC.Comment: 16 pages, 5 figure
Análisis comparativo de pacientes con lesiones estenóticas y ectásicas coronarias
A total number of 177 patients with coronary lesions were studied. Sixty nine of them presented either a combination of stenotic and ectatic lesions (n = 18) or isolated ectatic lesions (n = 51) and 108 presented only stenotic lesions. Analyzing several clinical and epidemiological parameters we observed a significant difference with respect to the higher prevalence of hypertension among the group affected by ectatic lesions. We verified as well a higher prevalence of myocardial infarction in the group of ectasia associated to the stenotic lesions. Finally, a higher global mortality was observed in the group of ectasia associated to stenotic lesions after medical or surgical treatment
Local detection of microvessels in IDH-wildtype glioblastoma using relative cerebral blood volume: an imaging marker useful for astrocytoma grade 4 classification
[EN] Background The microvessels area (MVA), derived from microvascular proliferation, is a biomarker useful for high-grade glioma classification. Nevertheless, its measurement is costly, labor-intense, and invasive. Finding radiologic correlations with MVA could provide a complementary non-invasive approach without an extra cost and labor intensity and from the first stage. This study aims to correlate imaging markers, such as relative cerebral blood volume (rCBV), and local MVA in IDH-wildtype glioblastoma, and to propose this imaging marker as useful for astrocytoma grade 4 classification. Methods Data from 73 tissue blocks belonging to 17 IDH-wildtype glioblastomas and 7 blocks from 2 IDH-mutant astrocytomas were compiled from the Ivy GAP database. MRI processing and rCBV quantification were carried out using ONCOhabitats methodology. Histologic and MRI co-registration was done manually with experts' supervision, achieving an accuracy of 88.8% of overlay. Spearman's correlation was used to analyze the association between rCBV and microvessel area. Mann-Whitney test was used to study differences of rCBV between blocks with presence or absence of microvessels in IDH-wildtype glioblastoma, as well as to find differences with IDH-mutant astrocytoma samples. Results Significant positive correlations were found between rCBV and microvessel area in the IDH-wildtype blocks (p < 0.001), as well as significant differences in rCBV were found between blocks with microvascular proliferation and blocks without it (p < 0.0001). In addition, significant differences in rCBV were found between IDH-wildtype glioblastoma and IDH-mutant astrocytoma samples, being 2-2.5 times higher rCBV values in IDH-wildtype glioblastoma samples. Conclusions The proposed rCBV marker, calculated from diagnostic MRIs, can detect in IDH-wildtype glioblastoma those regions with microvessels from those without it, and it is significantly correlated with local microvessels area. In addition, the proposed rCBV marker can differentiate the IDH mutation status, providing a complementary non-invasive method for high-grade glioma classification.This work was funded by grants from the National Plan for Scientific and Technical Research and Innovation 2017-2020, No. PID2019-104978RB-I00) (JMGG); H2020-SC1-2016-CNECT Project (No. 727560) (JMGG), and H2020SC1-BHC-2018-2020 (No. 825750) (JMGG). M.A.T was supported by DPI201680054-R (Programa Estatal de Promocion del Talento y su Empleabilidad en I + D + i). EFG was supported by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 844646. The funding body played no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.Álvarez-Torres, MDM.; Fuster García, E.; Juan-Albarracín, J.; Reynes, G.; Aparici-Robles, F.; Ferrer Lozano, J.; Garcia-Gomez, JM. (2022). Local detection of microvessels in IDH-wildtype glioblastoma using relative cerebral blood volume: an imaging marker useful for astrocytoma grade 4 classification. BMC Cancer. 22(1):1-13. https://doi.org/10.1186/s12885-021-09117-411322
On the nature of the fourth generation neutrino and its implications
We consider the neutrino sector of a Standard Model with four generations.
While the three light neutrinos can obtain their masses from a variety of
mechanisms with or without new neutral fermions, fourth-generation neutrinos
need at least one new relatively light right-handed neutrino. If lepton number
is not conserved this neutrino must have a Majorana mass term whose size
depends on the underlying mechanism for lepton number violation. Majorana
masses for the fourth generation neutrinos induce relative large two-loop
contributions to the light neutrino masses which could be even larger than the
cosmological bounds. This sets strong limits on the mass parameters and mixings
of the fourth generation neutrinos.Comment: To be published. Few typos corrected, references update
Imaging seminiferous tubules – a 9.4T MRI mouse model
Fertility problems affect many couples. Research into male fertility commonly uses mouse models due to their availability and similar spermatogenesis to humans. A common target is the seminiferous tubules, the site of spermatozoa production, typically studied using biopsies and histological analysis. High-field Magnetic Resonance (MR) may offer a non-invasive alternative to investigate testicular function in infertility models. Here, we assess seminiferous tubules structure in sacrificed mice to determine the usefulness of MR compared to histology. Twelve mice (11 aged 35-57 days, one >9 months) were sacrificed and MR imaged at 9.4T with a Rapid Acquisition with Relaxation Enhancement sequence. Testes were scanned in situ for all mice, and excised in a subset of mice (n=4). A second subset of mice (n=4) had their testes selected for histological analysis. Seminiferous tubule diameter was measured manually from MRI and histology images. Custom image analysis scripts were created for the automated segmentation of seminiferous tubules and calculation of tissue volumes. All ex vivo and in situ images of testes exhibited clear outlines of seminiferous tubules. Ratio of total testis volume to volume of seminiferous tubules did not differ significantly between ex vivo and in situ measurements, and were similar in mature and younger mice. Both total testis volume and seminiferous tubule volume were larger in the mature animal. While histological slices trended towards larger average seminiferous tubules diameter than MRI images, we found no significant differences between MRI and histological measurements. High-field MRI can be used in a mouse model to assess testicular structure in situ. All volumetric measurements compared favourably with histological data. In situ scans also clearly showed identifiable extra-testicular tissues, such as epididymis and prostate tissues. The potential to image tissues associated with sperm maturation as well as spermatogenesis emphasises how MR could be a useful technique in mouse models of fertility, however further work is required to optimize tissue segmentation and validate this method for use in longitudinal studies. This type of measurement could be extended to human fertility studies in the future
Laboratori virtual de psicologia bàsica: l'experiència com a clau de l'aprenentatge
El Laboratori Virtual de Psicologia Bàsica (LVPB) és una eina que acompanya l'estudiant en un recorregut a través d'experiments que s'han convertit en clàssics de la Psicologia Cognitiva. La plataforma reprodueix experiments provinents de l'estudi de l'atenció, l'emoció, el llenguatge, la memòria, la motivació, el pensament i la percepció. En cada experiment, l'LVPB presenta un text introductori amb alguns articles de referència on es van proposar per primera vegada aquests experiments. L'LVPB es basa en la plataforma d'aprenentatge electrònic Moodle, que permet que cada estudiant tingui el seu espai en el qual guardar les dades, els resultats i les anàlisis que hagi fet. Tota la interacció amb el sistema queda enregistrada i la pot consultar tant l'estudiant com el professorat en qualsevol moment. Això permet que l'LVPB es pugui utilitzar també com a eina d'avaluació del professor.El Laboratorio Virtual de Psicología Básica (LVPB) es una herramienta que acom-paña al estudiante en un recorrido a través de experimentos que se han convertidoen clásicos de la Psicología Cognitiva. La plataforma reproduce experimentos prove-nientes del estudio de la atención, la emoción, el lenguaje, la memoria, la motiva-ción, el pensamiento y la percepción.En cada experimento, el LVPB presenta un texto introductorio con algunos artí-culos de referencia donde se propusieron por primera vez estos experimentos.El LVPB se basa en la plataforma de aprendizaje electrónico Moodle, que permiteque cada estudiante tenga su espacio en el cual guardar los datos, los resultados ylos análisis que haya hecho. Toda la interacción con el sistema queda registrada y lapuede consultar tanto el estudiante como el profesorado en cualquier momento. Esopermite que el LVPB se pueda utilizar también como herramienta de evaluación delprofesor.The Virtual Basic Psychology Laboratory (VBPL) is a tool that accompanies thestudent on a journey through experiments that have become classics in the Cognitive Psychology field. The platform reproduces experiments from the study ofemotion, language, memory, motivation, thought and perception. In each experiment, the VBPL presents an introductory text with some articlesfor reference, where these experiments were suggested for the first time. The VBPL is based on the Moodle e-learning platform, which enables eachstudent to have their own space for saving the data, results and analysis that they haveproduced. All interaction with the system is recorded and can be consulted by boththe student and the teacher at any time. This also enables the VBPL to be used as anassessment tool by the teacher
Glioblastoma: Vascular Habitats Detected at Preoperative Dynamic Susceptibility-weighted Contrast-enhanced Perfusion MR Imaging Predict Survival
[EN] Purpose: To determine if preoperative vascular heterogeneity of glioblastoma is predictive of overall survival of patients undergoing standard-of-care treatment by using an unsupervised multiparametric perfusion-based habitat-discovery algorithm.
Materials and Methods: Preoperative magnetic resonance (MR) imaging including dynamic susceptibility-weighted contrast material-enhanced perfusion studies in 50 consecutive patients with glioblastoma were retrieved. Perfusion parameters of glioblastoma were analyzed and used to automatically draw four reproducible habitats that describe the tumor vascular heterogeneity: high-angiogenic and low-angiogenic regions of the enhancing tumor, potentially tumor-infiltrated peripheral edema, and vasogenic edema. Kaplan-Meier and Cox proportional hazard analyses were conducted to assess the prognostic potential of the hemodynamic tissue signature to predict patient survival.
Results: Cox regression analysis yielded a significant correlation between patients' survival and maximum relative cerebral blood volume (rCBV(max)) and maximum relative cerebral blood flow (rCBF(max)) in high-angiogenic and low-angiogenic habitats (P < .01, false discovery rate-corrected P < .05). Moreover, rCBF(max) in the potentially tumor-infiltrated peripheral edema habitat was also significantly correlated (P < .05, false discovery rate-corrected P < .05). Kaplan-Meier analysis demonstrated significant differences between the observed survival of populations divided according to the median of the rCBV(max) or rCBF(max) at the high-angiogenic and low-angiogenic habitats (log-rank test P < .05, false discovery rate-corrected P < .05), with an average survival increase of 230 days.
Conclusion: Preoperative perfusion heterogeneity contains relevant information about overall survival in patients who undergo standard-of-care treatment. The hemodynamic tissue signature method automatically describes this heterogeneity, providing a set of vascular habitats with high prognostic capabilities.Study supported by H2020 European Institute of Innovation and Technology (POC-2016.SPAIN-07) and Universitat Politecnica de Valencia (PAID-10-14). J.J.A., E.F.G., and J.M.G.G. supported by Secretaria de Estado de Investigacion, Desarrollo e Innovacion (DPI2016-80054-R, TIN2013-43457-R). E.F.G. supported by CaixaImpulse program from Fundacio Bancaria "la Caixa" (LCF/TR/CI16/10010016). E.F.G and A.A.B. supported by the Universitat Politecnica de Valencia Instituto Investigacion Sanitaria de La Fe (C05).Juan -Albarracín, J.; Fuster García, E.; Pérez-Girbés, A.; Aparici-Robles, F.; Alberich Bayarri, A.; Revert Ventura, AJ.; Martí Bonmatí, L.... (2018). Glioblastoma: Vascular Habitats Detected at Preoperative Dynamic Susceptibility-weighted Contrast-enhanced Perfusion MR Imaging Predict Survival. Radiology. 287(3):944-954. https://doi.org/10.1148/radiol.2017170845S944954287
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