1,442 research outputs found

    A nonpolynomial collocation method for fractional terminal value problems

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    NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Computational and Applied Mathematics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Computational and Applied Mathematics, 275, February 2015, doi: 10.1016/j.cam.2014.06.013In this paper we propose a non-polynomial collocation method for solving a class of terminal (or boundary) value problems for differential equations of fractional order α, 0 < α < 1. The approach used is based on the equivalence between a problem of this type and a Fredholm integral equation of a particular form. Taking into account the asymptotic behaviour of the solution of this problem, we propose a non-polynomial collocation method on a uniform mesh. We study the order of convergence of the proposed algorithm and a result on optimal order of convergence is obtained. In order to illustrate the theoretical results and the performance of the method we present several numerical examples.The work was supported by an International Research Excellence Award funded through the Santander Universities scheme

    An implicit finite difference approximation for the solution of the diffusion equation with distributed order in time

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    In this paper we are concerned with the numerical solution of a diffusion equation in which the time order derivative is distributed over the interval [0,1]. An implicit numerical method is presented and its unconditional stability and convergence are proved. A numerical example is provided to illustrate the obtained theoretical results

    Perioperative Medication Teaching Protocol: An Evidence-Based Project in a Perioperative Surgical Home

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    At the outpatient surgery center, there is a need for a perioperative medication guideline to improve appropriate medication teaching and compliance in the days and weeks leading up to a surgical intervention. It is critical that protocols and evidence-based guidelines are used throughout the management of all patients taking oral anticoagulants during the perioperative window. Currently, there is no standardized teaching protocol for patients preparing for surgery who are on anticoagulants. This lack of standardization could lead to increased surgical complications. Patient education is essential to preoperative optimization and can lead to improved patient compliance. This can be done by streamlining the education given to patients regarding their perioperative anticoagulant management, which increases effectiveness of the education and decrease adverse reactions. One solution, and the focus of this project, will be implementing a standardized medication teaching protocol, via the perioperative surgical home, to improve appropriate adherence in patients taking anticoagulants. The aim of the proposed project is that by May 30, 2021, 100% of perioperative nursing staff will receive the preoperative medication guideline, participate in the educational training, and demonstrate competency in knowledge of the guideline and patient education

    Fractional pennes' bioheat equation: Theoretical and numerical studies

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    Accepted for publication in Fractional calculus and applied analysisOriginally published in the journal Fract. Cal. Appl. Anal. Vol. 18 No. 4 / 2015 / pp.1080–1106 / DOI 10.1515/fca-2015-0062. The original publication is available at: http://www.degruyter.com/view/j/fca.2015.18.issue-4/fca-2015-0062/fca-2015-0062.xml?rskey=sWWcn0&result=1In this work we provide a new mathematical model for the Pennes’ bioheat equation, assuming a fractional time derivative of single order. Alternative versions of the bioheat equation are studied and discussed, to take into account the temperature-dependent variability in the tissue perfusion, and both finite and infinite speed of heat propagation. The proposed bio heat model is solved numerically using an implicit finite difference scheme that we prove to be convergent and stable. The numerical method proposed can be applied to general reaction diffusion equations, with a variable diffusion coefficient. The results obtained with the single order fractional model, are compared with the original models that use classical derivatives.The authors L.L. Ferras and J. M. Nobrega acknowledge financial funding by FEDER through the COMPETE 2020 Programme and by FCT- Portuguese Foundation for Science and Technology under the projects UID/CTM/50025/2013 and EXPL/CTM-POL/1299/2013. L.L. Ferras acknowledges financial funding by the Portuguese Foundation for Science and Technology through the scholarship SFRH/BPD/100353/2014. M. Rebelo acknowledges financial funding by the Portuguese Foundation for Science and Technology through the project UID/MAT/00297/2013

    Characterization and Quantification of Isoprene-Derived Epoxydiols in Ambient Aerosol in the Southeastern United States

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    Isoprene-derived epoxydiols (IEPOX) are identified in ambient aerosol samples for the first time, together with other previously identified isoprene tracers (i.e., 2-methyltetrols, 2-methylglyceric acid, C5-alkenetriols, and organosulfate derivatives of 2-methyltetrols). Fine ambient aerosol collected in downtown Atlanta, GA and rural Yorkville, GA during the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS) was analyzed using both gas chromatography/quadrupole mass spectrometry (GC/MS) and gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) with prior trimethylsilylation. Mass concentrations of IEPOX ranged from ~1 to 24 ng m^(−3) in the aerosol collected from the two sites. Detection of particle-phase IEPOX in the AMIGAS samples supports recent laboratory results that gas-phase IEPOX produced from the photooxidation of isoprene under low-NO_x conditions is a key precursor of ambient isoprene secondary organic aerosol (SOA) formation. On average, the sum of the mass concentrations of IEPOX and the measured isoprene SOA tracers accounted for about 3% of the organic carbon, demonstrating the significance of isoprene oxidation to the formation of ambient aerosol in this region

    Novel Sequence Variants in the NPC1 Gene in Egyptian Patients with Niemann-Pick Type C

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    BACKGROUND: Niemann-Pick disease type C (NPC) is a rare, autosomal recessive, progressive neuro-visceraldisease caused by biallelic mutations in either NPC1gene (95% of cases) or NPC2 gene. AIM: This caseseries study aimed at the molecular analysis of certain hot spots of NPC1 genein NPC Egyptian patients. METHODS: The study included 15 unrelated NPC patients and selected parents,as well as20 healthy controls of matched sex and age. Clinical investigations were performed according to well established clinical criteria. Assessment of the chitotriosidase level, as an initial screening tool for NPC, was done in all cases. Polymerase chain reaction amplification of NPC1 exons (17–25) encountering the hotspot residues (855–1098 and1038–1253) was carried out followed by direct sequencingfor mutational analysis. RESULTS: All includedpatients with mainly neurovisceral involvement were characterized. The onset of the disease varied from early-infantile (58.3%) to late-infantile (26.7%) and juvenile-onset (6.7%). Ahigh chitotriosidase level wasobservedin all patients. Molecular analysis of NPC1 (exons 17–25) confirmed 15 mutant alleles out of 30 studied ones. They included two novel homozygous missense variants (p.Ser1169Arg and p.Ser1197Phe) and previously reportedfour mutations (p.Arg958*, p.Gly910Ser, p.Ala927Glyfs*38, and andp.Cys1011*). CONCLUSION: The two studied amino acid residues (855–1098 and 1038–1253) could beconsidered aspotential hotspot regions in NPC1 Egyptian patients

    Protein retention in the endoplasmic reticulum rescues Aβ toxicity in Drosophila

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    Amyloid β (Aβ) accumulation is a hallmark of Alzheimer's disease. In adult Drosophila brains, human Aβ overexpression harms climbing and lifespan. It's uncertain whether Aβ is intrinsically toxic or activates downstream neurodegeneration pathways. Our study uncovers a novel protective role against Aβ toxicity: intra-endoplasmic reticulum (ER) protein accumulation with a focus on laminin and collagen subunits. Despite high Aβ, laminin B1 (LanB1) overexpression robustly counters toxicity, suggesting a potential Aβ resistance mechanism. Other laminin subunits and collagen IV also alleviate Aβ toxicity; combining them with LanB1 augments the effect. Imaging reveals ER retention of LanB1 without altering Aβ secretion. LanB1's rescue function operates independently of the IRE1α/XBP1 ER stress response. ER-targeted GFP overexpression also mitigates Aβ toxicity, highlighting broader ER protein retention advantages. Proof-of-principle tests in murine hippocampal slices using mouse Lamb1 demonstrate ER retention in transduced cells, indicating a conserved mechanism. Though ER protein retention generally harms, it could paradoxically counter neuronal Aβ toxicity, offering a new therapeutic avenue for Alzheimer's disease

    RELATIONSHIPS BETWEEN DAY CARE CENTER AND FAMILY ACCORDING TO DAY CARE CENTER´S EDUCATORS

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    Neste trabalho, apresentamos parte dos resultados de uma investigação cujo objetivo foi apreender e analisar as representações de educadoras de creches acerca do cuidado da criança, segundo o referencial da Teoria das Representações Sociais. Os dados foram coletados em três creches de uma universidade pública, no município de São Paulo, SP, durante uma oficina pedagógica. A análise dos conteúdos referentes à interação creche-família caracterizaram-na como uma relaçãodifícil e delicada, pois as educadoras tinham expectativas idealizadas a respeito das mães e das famílias, bem como dificuldades para lidar com as manifestações de seus sentimentos, principalmente no que diz respeito a como conversar sobre tais assuntos. Esses fatores constituem- se em barreiras à interação, que precisam ser identificadas e trabalhadas para uma possível superação e construção de parcerias efetivas para o cuidado/educação infantil. Diante desses resultados, propomos que sejam incluídos, na formação das educadoras, conteúdos sobre habilidades e técnicas de comunicação terapêutica.This article presents part of the results from an investigation aiming to understand and analyze representations of those who work in day care centers concerning child care according totheory of social representations. Data were collected at three day care centers of a public university in the city of São Paulo. The population consisted of nine educators – workers in charge of the direct activities with children –, who answered a questionnaire with questions related to personal features and on their association with infantile education. The educators had participated in a pedagogical workshop, organized in four group meetings, and their speech was analyzed according to the thematic analysis technique. The category day care center and family, approaching aspects regarding the interaction between workers and family, consisted of two sub-categories: factors involved in the interaction between the day care center staff and the family, including feelings, expectations, perceptions and parents’ and staff’s behavior which modulate these interactions and measures to favor interactions between day care center and family, such as: mutual respect, developing confidence and helping parents in their insecurity. The analysis of the content regarding the interaction day carecenter/ family characterizes it as a difficult and fragile relationship. It was observed that workers have an ideal view of mothers and families; they also have difficulties in dealing with manifestations of feelings, mainly regarding how to talk about them. These factors are barriers to the interaction, and they need to be identified and dealt with so that they can be overcome and effective partnerships for the infantile care/education can be built. Contents about abilities and therapeutic communication techniques are proposed to be included in the educator’s education

    ABC 2 -SPH risk score for in-hospital mortality in COVID-19 patients: development, external validation and comparison with other available scores

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    Coronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Hospitalitzacions; MortalitatCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Hospitalizaciones; MortalidadCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Hospitalizations; MortalityObjectives The majority of available scores to assess mortality risk of coronavirus disease 2019 (COVID-19) patients in the emergency department have high risk of bias. Therefore, this cohort aimed to develop and validate a score at hospital admission for predicting in-hospital mortality in COVID-19 patients and to compare this score with other existing ones. Methods Consecutive patients (≥ 18 years) with confirmed COVID-19 admitted to the participating hospitals were included. Logistic regression analysis was performed to develop a prediction model for in-hospital mortality, based on the 3978 patients admitted between March–July, 2020. The model was validated in the 1054 patients admitted during August–September, as well as in an external cohort of 474 Spanish patients. Results Median (25–75th percentile) age of the model-derivation cohort was 60 (48–72) years, and in-hospital mortality was 20.3%. The validation cohorts had similar age distribution and in-hospital mortality. Seven significant variables were included in the risk score: age, blood urea nitrogen, number of comorbidities, C-reactive protein, SpO 2 /FiO 2 ratio, platelet count, and heart rate. The model had high discriminatory value (AUROC 0.844, 95% CI 0.829–0.859), which was confirmed in the Brazilian (0.859 [95% CI 0.833–0.885]) and Spanish (0.894 [95% CI 0.870–0.919]) validation cohorts, and displayed better discrimination ability than other existing scores. It is implemented in a freely available online risk calculator (https://abc2sph.com/). Conclusions An easy-to-use rapid scoring system based on characteristics of COVID-19 patients commonly available at hospital presentation was designed and validated for early stratification of in-hospital mortality risk of patients with COVID-19.This study was supported in part by Minas Gerais State Agency for Research and Development ( Fundação de Amparo à Pesquisa do Estado de Minas Gerais – FAPEMIG ) [grant number APQ-00208-20], National Institute of Science and Technology for Health Technology Assessment ( Instituto de Avaliação de Tecnologias em Saúde – IATS )/ National Council for Scientific and Technological Development ( Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq ) [grant number 465518/2014-1], and CAPES Foundation ( Coordenação de Aperfeiçoamento de Pessoal de Nível Superior ) [grant number 88887.507149/2020-00]. AS was supported by a postdoctoral grant “Juan Rodés” (JE18/00022) from Instituto de Salud Carlos III through the Ministry of Economy and Competitiveness, Spain
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