3,859 research outputs found

    Effect of nitrogen gas in the agglomeration and photoluminescence of Zn-ZnO nanowires after high-temperature annealing

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    The effect of anti-agglomeration and enhanced photoluminescence after high-temperature annealing of Zn-ZnO nanowires in nitrogen at-mosphere is reported. The Zn-ZnO nanowires were deposited by the hot filament chemical vapor deposition technique and subsequentlyannealed at 1100±C in oxygen or nitrogen atmospheres. It was found that under both annealing atmospheres, the structure of the nanowireswas completely oxidized. Morphological studies suggest that annealing under oxygen-rich atmosphere, grain growth occurs, resulting in acontinuous surface with a micrograin-shaped structure. However, it seems that nitrogen-rich annealing partially prevents complete agglom-eration and longitudinal structures composed by nanometric grains were observed. Although photoluminescence properties of the annealednanowires are improved in both annealing atmospheres, it was observed that the PL spectrum of nanowires annealed in nitrogen showed astronger UV emission than that of the oxygen annealed nanowires

    Statistical analysis of Ni nanowires breaking processes: a numerical simulation study

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    A statistical analysis of the breaking behavior of Ni nanowires is presented. Using molecular dynamic simulations, we have determined the time evolution of both the nanowire atomic structure and its minimum cross section (Sm(t)). Accumulating thousands of independent breaking events, Sm histograms are built and used to study the influence of the temperature, the crystalline stretching direction and the initial nanowire size. The proportion of monomers, dimers and more complex structures at the latest stages of the breaking process are calculated, finding important differences among results obtained for different nanowire orientations and sizes. Three main cases have been observed. (A) [111] stretching direction and large nanowire sizes: the wire evolves from more complex structures to monomers and dimers prior its rupture; well ordered structures is presented during the breaking process. (B) Large nanowires stretched along the [100] and [110] directions: the system mainly breaks from complex structures (low probability of finding monomers and dimers), having disordered regions during their breakage; at room temperature, a huge histogram peak around Sm=5 appears, showing the presence of long staggered pentagonal Ni wires with ...-5-1-5-... structure. (C) Initial wire size is small: strong size effects independently on the temperature and stretching direction. Finally, the local structure around monomers and dimmers do not depend on the stretching direction. These configurations differ from those usually chosen in static studies of conductance.Comment: 18 pages, 13 figure

    Prevalencia de insuficiencia renal «oculta» en población diabética tipo 2

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    ObjetivoDeterminar la prevalencia de insuficiencia renal en diabĂ©ticos tipo 2 y comparar dos criterios de definiciĂłn: el basado en la estimaciĂłn del filtrado glomerular por la fĂłrmula de Cockcroft-Gault corregida para la superficie corporal y el basado en la creatinina sĂ©rica.DiseñoEstudio descriptivo y transversal.EmplazamientoZona bĂĄsica del Centro de Salud de El Cristo, Oviedo.ParticipantesLa totalidad de pacientes diabĂ©ticos tipo 2 diagnosticados de la zona bĂĄsica.Mediciones principalesSe recogieron datos demogrĂĄficos, clĂ­nicos, factores de riesgo y enfermedad cardiovascular. Se diagnosticĂł insuficiencia renal (IR) segĂșn unas cifras de creatinina plasmĂĄtica ≄ 1,3 mg/dl en mujeres y ≄ 1,4 mg/dl en varones y segĂșn el filtrado glomerular (FG) estimado mediante la fĂłrmula de Cockcroft-Gault: moderada para FG, 60-30 ml/min/1,73 m2; grave para FG, 29-15 ml/min/1,73 m2, y terminal para FG, < 15 ml/min/1,73 m2.ResultadosSe incluyĂł a 499 pacientes. El 52,3% era mujer con una edad de 69,7 ± 0,4 años. La prevalencia de IR segĂșn la creatinina sĂ©rica fue del 12%, y segĂșn la fĂłrmula de Cockcroft-Gault del 40,5%. Los pacientes con FG reducido y creatinina normal tenĂ­an mayor edad (75,5 ± 7,9 frente a 65,4 ± 9,8 años; p < 0,001), predominaban las mujeres (76,3 frente a 41,7%; p < 0,001), tenĂ­an un menor Ă­ndice de masa corporal (27,3 ± 3,7 frente a 30,9 ± 4,4), presentaban un peor control glucĂ©mico (HbA1c 7,1 ± 1,8 frente a 6,9 ± 1,9%; p = 0,007) y la prevalencia de insuficiencia cardĂ­aca era superior (6,4 frente a 2,1%; IC del 95%, 1,1-8,8; p = 0,02) en comparaciĂłn con los pacientes con FG y creatinina normales.ConclusiĂłnLa estimaciĂłn del FG por la fĂłrmula de Cockcroft-Gault corregida para la superficie corporal muestra una insuficiencia renal no conocida en uno de cada 3 pacientes diabĂ©ticos tipo 2.ObjectiveTo determine the prevalence of renal failure (RF) in type-2 diabetics and to compare two criteria of definition: that based on the calculation of glomerular filtration by the Cockcroft-Gault formula corrected for body surface area and that based on serous creatinine.DesignCross-sectional, descriptive study.SettingEl Cristo Health Centre,Oviedo, north of Spain.ParticipantsAll patients in the catchment area diagnosed with type-2 diabetes.MethodDemographic, clinical, risk factor, and cardiovascular pathology details were gathered. Renal failure was diagnosed on figures of plasma creatinine ≄1.3 mg/dL in women and ≄1.4 mg/dL in men, and glomerular filtration (GF) calculated by means of the Cockcroft-Gault formula: moderate GF, 60-30 mL/min/1.73 m2; severe GF, 29-15 mL/min/1.73 m2, and terminal GF: <15 mL/min/1.73 m2.Results499 patients were included. 52.3% were women, aged 69.7±10.4 years old. Prevalence of RF by serous creatinine was 12%; and by the Cockcroft-Gault formula, 40.5%. Patients with lower glomerular filtration and normal creatinine were older (75.5±7.9 vs 65.4±9.8; P<.001), mainly female (76.3% vs 41.7%; P<.001), had lower BMI (27.3±3.7 vs 30.9±4.4) and had worse glucaemia control (HbA1c 7.1±1.8% vs 6.9±1.9%; P=.007) and higher indices of cardiac failure (6.4% vs 2.1%; 95% CI, 1.1- 8.8; P=.02) than patients with normal glomerular filtration and creatinine.ConclusionCalculation of glomerular filtration by the Cockcroft-Gault formula corrected for body surface area revealed unknown renal failure in 1 in 3 type-2 diabetes patients

    ÂżSon los alumnos capaces de atribuir a los microorganismos algunas transformaciones de los alimentos?

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    In this paper we investigate if primary school students are able to relate microorganisms with food transformations. The subjects of this study were 343 4th. and 7th. grade children from Lugo (Spain) and the instrument used consisted of four multiple choice questions. The results shed light on the difficulties students have at these levels when they try to apply their ideas to interpret biological phenomena. Finally, we discuss some implications for Science teaching and learning

    Theoretical adequacy, methodological quality and efficacy of online interventions targeting resilience: a systematic review and meta-analysis

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    BACKGROUND: There is a growing interest in the promotion of mental health, and concepts as resilience are re-emerging and taking relevance. In addition, Information and Communication Technologies can provide potential benefits in the field of mental health, and the treatment of mental disorders in particular. This study aims to synthesize the evidence of internet-based resilience interventions, analyzing the theoretical adequacy, methodological quality and efficacy. METHODS: A systematic search was performed. The eligibility criteria stated for this article were: randomized controlled trials targeted at adults or adolescents and including any psychological intervention focussing on resilience in its rationale or design. Studies with direct (e.g. resilience scales) and proximal resilience measures (e.g. scales on well-being) were included. Risk of bias was assessed for each trial using Cochrane''s Collaboration Tool. Two reviewers worked independently in order to identify potential articles. A total of 11 articles were selected. A random-effects pooling model using the Hartung-Knapp-Sidik-Jonkman method based on direct and proximal resilience measures at post-test was used. RESULTS: The overall effects of online resilience training compared to control groups at post-test were not significant; the effect size concerning the improvement of resilience was g=0.12 (95% CI: -0.14 to 0.38). In addition, a potential association between the type of outcome and the effect size could be revealed. CONCLUSIONS: The results of the present meta-analysis showed that the overall effect of online resilience trainings was not significant. Nonetheless, a tendency for a higher benefit for resilience was found in the studies with a clear assessment theory, indicating some promising effects. REGISTRATION NUMBER: PROSPERO CRD42018083339. © The Author(s) 2021. Published by Oxford University Press on behalf of the European Public Health Association

    Exercises using a touchscreen tablet application improved functional ability more than an exercise program prescribed on paper in people after surgical carpal tunnel release: a randomised trial

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    Question: In people who have undergone surgical carpal tunnel release, do sensorimotor-based exercises performed on the touchscreen of a tablet device improve outcomes more than a conventional home exercise program prescribed on paper? Design: Randomised, parallel-group trial with concealed allocation, assessor blinding, and intention-to-treat analysis. Participants: Fifty participants within 10 days of surgical carpal tunnel release. Intervention: Each participant was prescribed a 4-week home exercise program. Participants in the experimental group received the ReHand tablet application, which administered and monitored exercises via the touchscreen. The control group was prescribed a home exercise program on paper, as is usual practice in the public hospital system. Outcome measures: The primary outcome was functional ability of the hand, reported using the shortened form of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire. Secondary outcomes were grip strength, pain intensity measured on a 10-cm visual analogue scale, and dexterity measured with the Nine-Hole Peg Test. Outcomes were measured by a blinded assessor at baseline and at the end of the 4-week intervention period. Results: At Week 4, functional ability improved significantly more in the experimental group than the control group (MD –21, 95% CI –33 to –9) on the QuickDASH score (0 to 100). Although the mean estimates of effect on the secondary outcome also all favoured the experimental group, none reached statistical significance: grip strength (MD 5.6 kg, 95% CI –0.5 to 11.7), pain (MD –1.4 cm, 95% CI –2.9 to 0.1), and dexterity (MD –1.3 seconds, 95% CI –3.7 to 1.1). Conclusion: Use of the ReHand tablet application for early rehabilitation after carpal tunnel release is more effective in the recovery of functional ability than a conventional home exercise program. It remains unclear whether there are any benefits in grip strength, pain or dexterity. Trial registration: ACTRN12618001887268

    Learning a Battery of COVID-19 Mortality Prediction Models by Multi-objective Optimization

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    The COVID-19 pandemic is continuously evolving with drastically changing epidemiological situations which are approached with different decisions: from the reduction of fatalities to even the selection of patients with the highest probability of survival in critical clinical situations. Motivated by this, a battery of mortality prediction models with different performances has been developed to assist physicians and hospital managers. Logistic regression, one of the most popular classifiers within the clinical field, has been chosen as the basis for the generation of our models. Whilst a standard logistic regression only learns a single model focusing on improving accuracy, we propose to extend the possibilities of logistic regression by focusing on sensitivity and specificity. Hence, the log-likelihood function, used to calculate the coefficients in the logistic model, is split into two objective functions: one representing the survivors and the other for the deceased class. A multi-objective optimization process is undertaken on both functions in order to find the Pareto set, composed of models not improved by another model in both objective functions simultaneously. The individual optimization of either sensitivity (deceased patients) or specificity (survivors) criteria may be conflicting objectives because the improvement of one can imply the worsening of the other. Nonetheless, this conflict guarantees the output of a battery of diverse prediction models. Furthermore, a specific methodology for the evaluation of the Pareto models is proposed. As a result, a battery of COVID-19 mortality prediction models is obtained to assist physicians in decision-making for specific epidemiological situations.This research is supported by the Basque Government (IT1504- 22, Elkartek) through the BERC 2022–2025 program and BMTF project, and by the Ministry of Science, Innovation and Universities: BCAM Severo Ochoa accreditation SEV-2017-0718 and PID2019-104966GB-I00. Furthermore, the work is also supported by the AXA Research Fund project “Early prognosis of COVID-19 infections via machine learning”
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