96 research outputs found

    Efficient simulation of Mechanism Kinematics Using Bond Graphs.

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    This paper presents a methodology for obtaining the equations corresponding to a mechanism that are necessary for carrying out a kinematic simulation. A simulation of this kind means obtaining the coordinates dependent on the system according to the movements imposed by the degrees of freedom. Unlike a dynamic simulation, where the set of elements moves according to the different external forces existing, in kinematic simulation the movement of the whole set depends exclusively on imposing movement on one or more of the bodies according to the degrees of freedom initially possessed by the mechanism. After presenting an analysis of how to obtain the necessary equations for several simple systems, this methodology is applied to the particular case of a front-loader, where in order to move and tilt the bucket, various closed mechanisms are integrated

    First Report of Anthelmintic Resistance in Gastrointestinal Nematodes of Sheep from Costa Rica

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    As the prevalence and severity of anthelmintic resistance continue to rise, nematode infections in sheep correspondingly reduce the profitability of the sheep industry. In Costa Rica, sheep production systems are increasing in both number and importance. A field trial study was carried out to detect the level of anthelmintic resistance to albendazole and ivermectin in gastrointestinal nematodes (GIN) of sheep from seven farms in Costa Rica. Resistance was determined using the fecal egg count reduction test (FECRT). Three treatment groups were assessed on each farm: control, albendazole, and ivermectin. Haemonchus spp. (71%), Strongyloides sp. (57%), and Trichostrongylus spp. (43%) presented resistance levels to albendazole, whereas Strongyloides sp. (43%), Haemonchus spp. (29%), and Trichostrongylus spp. (29%) were resistant to ivermectin. Haemonchus spp., Strongyloides sp., and Trichostrongylus spp. were the most resistant GIN to both products. This study suggests that frequency of treatment, exclusive chemical control, and visual estimation of animal weight to calculate dosage may contribute to the high levels of anthelmintic resistance that were observed on the farms analyzed herein

    Zeolitization of Diatomite Residues by a Simple Method

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    Abstract The possibility of transforming a diatomite-rich waste from the brewing industry into synthetic zeolites has been investigated. After precalcination at 550 °C to eliminate the retained organic matter, the clean diatomite (Dt; with a Si/Al molar ratio of 17.4), was hydrothermally treated for 24 h with continuous stirring in a 3M NaOH solution at 80 °C. The results of mineralogical characterization by X-ray diffraction with Rietveld refinement have shown a crystallization of 55% of zeolite P, which was neoformed from the amorphous phase, opal-CT and quartz of the starting sample. The spectra obtained by Fourier Transform Infrared Spectrometry have corroborated such zeolitization. N2 adsorption–desorption isotherms have shown that the zeolitized material (Dt-Z) is mesoporous, with almost 60% more specific surface area than Dt (62.6 m2/g vs. 39.4 m2/g), greater microporosity and 40% smaller average pore size than Dt (71 Å vs. 118 Å). This study is a first approximation to know the potential of diatomite wastes as zeolite precursors, for which additional research including an aluminum source will be required.This research was conducted as a part of the ECO-MET-AL Project, PID2019-109520RB-I00/AEI/10.13039/501100011033, “Can industrial and mining metalliferous wastes produce green lightweight aggregates? Applying the Circular Economy” funded by the Spanish Ministry of Science, Innovation and Universities and ERDF funds, framed in the “Ayudas a “Proyectos I+D+i” en el marco de los Programas Estatales de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema de I+D+i y de I+D+i orientada a los Retos de la Sociedad, Convocatoria 2019”. Thanks also to the SCAI of the University of Jaén, the University of Castilla-La Mancha and the University of Málaga for their services. The authors also acknowledge the Postdoctoral Contract granted through the Resolution of 21 May 2020, of the General Secretariat for Universities, Research and Technology of the Government of Andalusia (Spain) within the scope of the Andalusian Plan for Research, Development and Innovation (PAIDI 2020)

    Virtual reality applied to a full simulator of electrical sub-stations

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    This paper presents an application designed to train electrical sub-station operators by means of a virtual reality environment. The application allows full viewing of any of the sub-stations in the power supply network. With the appropriate hardware (HMD, 3D mouse and tracking systems) it is possible to navigate into the virtual world and interact with the elements. Each of the sub-station components has been reproduced in the simulation model, including the behavior laws associated with it, so the complete functionality of the sub-station can be simulated. This module is built into a larger and more complex computer system composed of the actual sub-station control system, the Geographical Information System which defines the topology of the network, and the functional system which simulates the electrical behavior of the sub-station. The application automatically updates in the virtual environment any changes to the sub-station's design and allows access, from this environment, to information on every component. The virtual reality application has been implemented in a hardware configuration and has the same interface as that used in the control system of the real sub-station. In this way, the system developed can be integrated into a replica of the complete power supply network control system emulating a real sub-station, it being able to fully interact with the global system, and allow totally real situations to be simulated

    Adherence to nucleos(t)ide analogue therapies for chronic Hepatitis B infection: A systematic review and meta-analysis

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    Successful treatment outcomes for chronic hepatitis B virus (HBV) infection requires high levels of adherence to treatment. We searched three databases and abstracts from two conferences up to January 2018 for studies reporting the proportion of patients who were adherent to HBV antiviral therapy and pooled data using random effects meta‐analysis. We included 30 studies, providing data for 23,823 patients. Overall, adherence to treatment was 74.6% (95% confidence interval [CI] 67.1%‐82.1%). Adherence was similar in high‐income settings (75.1%; 95% CI, 65.4%‐85.0%) and in low‐income and middle‐income settings (72.9%; 95% CI, 57.8%‐88.0%). Reported barriers to adherence included forgetting, limited understanding of the importance of adherence, and change to routine. Conclusion: There is a need to reinforce assessment and reporting of adherence as a routine part of HBV care and to assess the extent to which evidence‐based interventions to improve adherence to medication for human immunodeficiency virus [HIV] and other chronic diseases are effective for HBV infection

    Development and Validation of Hepamet Fibrosis Scoring System-a Simple, Non-invasive Test to Identify Patients With Nonalcoholic Fatty liver Disease With Advanced Fibrosis

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    BACKGROUND & AIMS: Fibrosis affects prognoses for patients with nonalcoholic fatty liver disease (NAFLD). Several non-invasive scoring systems have aimed to identify patients at risk for advanced fibrosis, but inconclusive results and variations in features of patients (diabetes, obesity and older age) reduce their diagnostic accuracy. We sought to develop a scoring system based on serum markers to identify patients with NAFLD at risk for advanced fibrosis. METHODS: We collected data from 2452 patients with NAFLD at medical centers in Italy, France, Cuba, and China. We developed the Hepamet fibrosis scoring system using demographic, anthropometric, and laboratory test data, collected at time of liver biopsy, from a training cohort of patients from Spain (n=768) and validated the system using patients from Cuba (n=344), Italy (n=288), France (n=830), and China (n=232). Hepamet fibrosis score (HFS) were compared with those of previously developed fibrosis scoring systems (the NAFLD fibrosis score [NFS] and FIB-4). The diagnostic accuracy of the Hepamet fibrosis scoring system was assessed based on area under the receiver operating characteristic (AUROC) curve, sensitivity, specificity, diagnostic odds ratio, and positive and negative predictive values and likelihood ratios. RESULTS: Variables used to determine HFS were patient sex, age, homeostatic model assessment score, presence of diabetes, levels of aspartate aminotransferase, and albumin, and platelet counts; these were independently associated with advanced fibrosis. HFS discriminated between patients with and without advanced fibrosis with an AUROC curve value of 0.85 whereas NFS or FIB-4 did so with AUROC values of 0.80 (P=.0001). In the validation set, cut-off HFS of 0.12 and 0.47 identified patients with and without advanced fibrosis with 97.2% specificity, 74% sensitivity, a 92% negative predictive value, a 76.3% positive predictive value, a 13.22 positive likelihood ratio, and a 0.31 negative likelihood ratio. HFS were not affected by patient age, body mass index, hypertransaminasemia, or diabetes. The Hepamet fibrosis scoring system had the greatest net benefit in identifying patients who should undergo liver biopsy analysis and led to significant improvements in reclassification, reducing the number of patients with undetermined results to 20% from 30% for the FIB-4 and NFS systems (P<.05). CONCLUSIONS: Using clinical and laboratory data from patients with NAFLD, we developed and validated the Hepamet fibrosis scoring system, which identified patients with advanced fibrosis with greater accuracy than the FIB-4 and NFS systems. the Hepamet system provides a greater net benefit for the decision-making process to identify patients who should undergo liver biopsy analysis

    Muticenter spanish study for perioperative stroke risk prediction after isolated coronary artery bypass surgery: The PACK2 score

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    [ES] Objetivos: Desarrollar un modelo predictivo multivariante del accidente cerebrovascular (ACV) intrahospitalario tras cirugía de bypass coronario. Métodos: Veintiséis mil trescientos cuarenta y siete pacientes incluidos en el estudio procedentes de 21 bases de datos de hospitales españoles. El análisis de regresión logística fue utilizado para predecir el riesgo de ACV perioperatorio (ictus o accidente isquémico transitorio). El modelo predictivo fue desarrollado a partir de un subgrupo de datos «de prueba» y validado en otro subgrupo independiente, ambos seleccionados aleatoriamente del total de la muestra. La capacidad predictiva del modelo se relacionó con el área bajo la curva ROC (ABC). Las variables consideradas fueron: preoperatorias (edad, sexo, diabetes mellitus, hipertensión arterial, ACV previo, insuficiencia cardiaca y/o fracción de eyección del ventrículo izquierdo < 40%, prioridad de la intervención no electiva, arteriopatía extracardiaca, insuficiencia renal crónica y/o creatininemia &#8805; 2 mg/dl y fibrilación auricular) e intraoperatorias (cirugía coronaria con/sin circulación extracorpórea). Resultados: Incidencia global de ACV perioperatorio 1,38%. La prioridad no electiva de la cirugía (priority; OR = 2,32), arteriopatía extracardiaca (arteriopathy; OR = 1,37), insuficiencia cardiaca (cardiac; OR = 3.64) e insuficiencia renal crónica (kidney; OR = 6,78) fueron identificados como factores de riesgo independientes de ACV perioperatorio en los modelos uni y multivariante en el subgrupo de prueba; p < 0,0001; ABC = 0,77, IC del 95%, 0,73-0,82. El modelo PACK2 de ACV perioperatorio tras cirugía de bypass coronario se estableció con 1 punto para cada ítem, excepto para la insuficiencia renal crónica que se le otorgaron 2 puntos (rango 0-5 puntos); ABC = 0,76, IC del 95%, 0,72-0,80. En pacientes con puntuación PACK2 &#8805; 2 puntos, la cirugía coronaria sin circulación extracorpórea redujo la incidencia de ACV en un 2,3% cuando se comparó con el grupo con cirugía realizada con circulación extracorpórea. Conclusiones: La escala de riesgo PACK2 muestra una buena capacidad predictiva en los datos analizados y podría ser útil en la toma de decisiones y selección de pacientes de la práctica clínica.[EN] Objectives: To develop a multivariate predictive risk score of perioperative in-hospital stroke after coronary artery bypass grafting (CABG) surgery. Methods: A total of 26,347 patients were enrolled from 21 Spanish hospital databases. Logistic regression analysis was used to predict the risk of perioperative stroke (stroke or transient ischaemic attack). The predictive scale was developed from a training set of data and validated by an independent test set, both selected randomly from the global sample. The assessment of the accuracy of prediction was related to the area under the ROC curve (AUC). The variables considered were: preoperative (age, gender, diabetes mellitus, arterial hypertension, previous stroke, cardiac failure and/or left ventricular ejection fraction < 40%, non-elective priority of surgery, extracardiac arteriopathy, chronic kidney failure and/or serum creatinine ≥2 mg/dl, and atrial fibrillation) and intra-operative (on/off-pump). Results: The overall perioperative stroke incidence was 1.38%. Non-elective priority of surgery (priority; OR = 2.32), vascular disease (arteriopathy; OR = 1.37), heart failure (cardiac; OR = 3.64), and chronic kidney failure (kidney; OR = 6.78) were found to be independent risk factors for perioperative stroke in uni- and multivariate models in the training set of data; P < .0001; AUC = 0.77, 95% CI 0.73–0.82. The PACK2 stroke CABG score was established with 1 point for each item, except for chronic kidney failure with 2 points (range 0–5 points); AUC = 0.76, 95% CI 0.72–0.80. In patients with PACK2 score ≥2 points, off-pump reduced perioperative stoke incidence by 2.3% when compared with on-pump CABG. Conclusions: PACK2 risk scale shows good predictive accuracy in the data analysed and could be useful in clinical practice for decision making and patient selection.Martín, E.; Hornero, F.; Rodríguez, R.; Castellà, M.; Porras, C.; Romero, B.; Maroto, L.... (2014). Estudio multicéntrico español para la predicción del riesgo perioperatorio de accidente cerebrovascular tras cirugía de bypass coronario aislada: el modelo PACK2. Cirugia Cardiovascular. 21(3):175-180. doi:10.1016/j.circv.2014.02.009S17518021

    p21-Activated Kinases Are Required for Transformation in a Cell-Based Model of Neurofibromatosis Type 2

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    NF2 is an autosomal dominant disease characterized by development of bilateral vestibular schwannomas and other benign tumors in central nervous system. Loss of the NF2 gene product, Merlin, leads to aberrant Schwann cell proliferation, motility, and survival, but the mechanisms by which this tumor suppressor functions remain unclear. One well-defined target of Merlin is the group I family of p21-activated kinases, which are allosterically inhibited by Merlin and which, when activated, stimulate cell cycle progression, motility, and increased survival. Here, we examine the effect of Pak inhibition on cells with diminished Merlin function.Using a specific peptide inhibitor of group I Paks, we show that loss of Pak activity restores normal cell movement in cells lacking Merlin function. In addition, xenografts of such cells form fewer and smaller tumors than do cells without Pak inhibition. However, in tumors, loss of Pak activity does not reduce Erk or Akt activity, two signaling proteins that are thought to mediate Pak function in growth factor pathways.These results suggest that Pak functions in novel signaling pathways in NF2, and may serve as a useful therapeutic target in this disease

    Incidence, clinical characteristics and management of inflammatory bowel disease in Spain: large-scale epidemiological study

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    (1) Aims: To assess the incidence of inflammatory bowel disease (IBD) in Spain, to describe the main epidemiological and clinical characteristics at diagnosis and the evolution of the disease, and to explore the use of drug treatments. (2) Methods: Prospective, population-based nationwide registry. Adult patients diagnosed with IBD—Crohn’s disease (CD), ulcerative colitis (UC) or IBD unclassified (IBD-U)—during 2017 in Spain were included and were followed-up for 1 year. (3) Results: We identified 3611 incident cases of IBD diagnosed during 2017 in 108 hospitals covering over 22 million inhabitants. The overall incidence (cases/100, 000 person-years) was 16 for IBD, 7.5 for CD, 8 for UC, and 0.5 for IBD-U; 53% of patients were male and median age was 43 years (interquartile range = 31–56 years). During a median 12-month follow-up, 34% of patients were treated with systemic steroids, 25% with immunomodulators, 15% with biologics and 5.6% underwent surgery. The percentage of patients under these treatments was significantly higher in CD than UC and IBD-U. Use of systemic steroids and biologics was significantly higher in hospitals with high resources. In total, 28% of patients were hospitalized (35% CD and 22% UC patients, p < 0.01). (4) Conclusion: The incidence of IBD in Spain is rather high and similar to that reported in Northern Europe. IBD patients require substantial therapeutic resources, which are greater in CD and in hospitals with high resources, and much higher than previously reported. One third of patients are hospitalized in the first year after diagnosis and a relevant proportion undergo surgery. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Pushing the high count rate limits of scintillation detectors for challenging neutron-capture experiments

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    One of the critical aspects for the accurate determination of neutron capture cross sections when combining time-of-flight and total energy detector techniques is the characterization and control of systematic uncertainties associated to the measuring devices. In this work we explore the most conspicuous effects associated to harsh count rate conditions: dead-time and pile-up effects. Both effects, when not properly treated, can lead to large systematic uncertainties and bias in the determination of neutron cross sections. In the majority of neutron capture measurements carried out at the CERN n\_TOF facility, the detectors of choice are the C6_{6}D6_{6} liquid-based either in form of large-volume cells or recently commissioned sTED detector array, consisting of much smaller-volume modules. To account for the aforementioned effects, we introduce a Monte Carlo model for these detectors mimicking harsh count rate conditions similar to those happening at the CERN n\_TOF 20~m fligth path vertical measuring station. The model parameters are extracted by comparison with the experimental data taken at the same facility during 2022 experimental campaign. We propose a novel methodology to consider both, dead-time and pile-up effects simultaneously for these fast detectors and check the applicability to experimental data from 197^{197}Au(nn,γ\gamma), including the saturated 4.9~eV resonance which is an important component of normalization for neutron cross section measurements
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