Avaliação da interação de citral, geraniol e timol no ácaro-vermelho-das-aves Dermanyssus gallinae (DE GEER, 1778) em condições in vitro

The control of Dermanyssus gallinae in small productions of laying hens is carried out by using chemical methods. However, its indiscriminate use has generated resistance and environmental pollution problems. This problem has encouraged the use of natural substances to control mites. Thus, the objective of this work was to evaluate the acaricidal activity of the bioactive citral (Ci), geraniol (Ge) and thymol (Thy) on D. gallinae under in vitro conditions using six concentrations (0.05, 1, 2, 3, 4 and 5g/mL). In addition, the interactions of the mixtures of the three bioactive were evaluated through binary (1:1) and tertiary (1:1:1) combinations. The interaction between of the combination of bioactive was performed by using CompuSyn software and calculating the combination index (CI). LC50, LC90, and LC99 with 95% confidence limits were estimated by Probit analysis. The bioactive Ci, Ge and Thy show acaricidal activity on the poultry red mite. The combination of Ge:Thy and Ci:Ge showed very strong synergism with CI of 0.084 and 0.052, whereas Ci:Thy showed strong synergism with CI of 0.122 at a concentration of 0.05g/mL. The tertiary combination in 1:1:1 showed a higher toxic effect and strong synergistic effects at low concentrations with 100% mortality at 1g/mL concentration with a CI of 0.147. The combination of natural bioactive could be an additional way to control D. gallinae without putting the welfare of the birds at risk and would be an environmentally friendly measure.    O controle de Dermanyssus gallinae em pequenas produções de poedeiras é realizado por métodos químicos. No entanto, seu uso indiscriminado tem gerado problemas de resistência e poluição ambiental. Este problema tem incentivado o uso de substâncias naturais para o controle de ácaros. Assim, o objetivo deste trabalho foi avaliar a atividade acaricida dos bioativos citral (Ci), geraniol (Ge) e timol (Thy) sobre D. gallinae em condições in vitro utilizando seis concentrações (0,05, 1, 2, 3, 4 e 5g/mL). Além disso, as interações das misturas dos três bioativos foram avaliadas por meio de combinações binárias (1:1) e terciárias (1:1:1). O sinergismo da combinação dos bioativos foi realizado utilizando o software CompuSyn e calculando o índice de combinação (CI). LC50, LC90 e LC99 com limites de confiança de 95% foram estimados por análise Probit. Os bioativos Ci, Ge e Thy apresentam atividade acaricida sobre o ácaro-vermelho-da-aves. A combinação de Ge:Thy e Ci:Ge apresentou sinergismo muito forte com CI de 0,084 e 0,052, enquanto Ci:Thy apresentou forte sinergismo com CI de 0,122 na concentração de 0,05g/mL. A combinação terciária em 1:1:1 apresentou maior efeito tóxico e fortes efeitos sinérgicos em baixas concentrações com 100% de mortalidade em concentração de 1g/mL com CI de 0,147. A combinação de bioativos naturais poderia ser uma forma adicional de controle de D. gallinae sem colocar em risco o bem-estar das aves e seria uma medida ecologicamente correta

Localization of Leaks in Water Distribution Networks using Flow Readings

This paper presents a novel approach to localize single and sequential leaks based on the lumped model of a water distribution network (WDN). The principal features of such a model are: a new friction term expressed as a power-law and a suitable representation expressed only in terms of the flow rate. From the response of this model and flow rate measurements at junctions of the pipelines composing the WDN, a set of residuals1 is proposed for each pipeline. The residuals closest to zero will indicate the leak positions in the faulty pipelines. We present some simulation tests based on data from PipelineStudio® from Energy Solutions to illustrate the suitability of our method

Parameter identification of periodical signals: Application to measurement and analysis of ocean wave forces

This article presents an approach based on state observers to identify the parameters of an unknown periodic force exerted on a mechanical system. This approach comprises two stages and can be executed in real time by using only displacement measurements. The first stage goal is the estimation of the coefficients of a Fourier series that approximates the periodic force. From the estimated coefficients, the phase and the amplitude of the signal can be simultaneously computed; and from the estimated force, in a second stage, the frequencies of the signal can be estimated. To perform the tasks at each stage, two state observers were designed. To show the applicability of the proposed approach, the reconstruction of a wave force affecting a marine structure as well as the computation of the amplitude and phase of its spectral components was taken as case of study. The performance of the state observer was examined by means of simulations and off-line tests carried out with experimental data. Such data were obtained by executing laboratory tests and measuring waves in the Caribbean sea

Towards an eco-friendly coffee rust control : compilation of natural alternatives from a nutritional and antifungal perspective

Hemileia vastatrix (HV) is the pathogen responsible for the coffee leaf rust (CLR) disease that has spread globally. CLR causes losses of up to a billion dollars annually and affects all types of crops regardless of their production regime (organic or inorganic). Additionally, smallholders produce approximately 80% of coffee in developing countries. The condition causes losses of up to a billion dollars annually. It affects all types of crops regardless of their production regime (organic or inorganic). Approximately 80% of coffee is produced by smallholders in developing countries. Until the 90s, shaded-production systems and native varieties were encouraged; however, the rapid spread of CLR has forced farmers to migrate towards inorganic schemes, mainly due to a lack of knowledge about natural alternatives to pesticides that can be implemented to control HV. Therefore, the purpose of this article is to compile the currently existing options, emphasizing two key factors that guarantee efficient rust control: selective fungicidal activity against HV and the nutrition of coffee crops. Thus, by comprehending how these natural compounds (such as plant, bacteria, fungi, animals, or algae metabolites) impact coffee rust proliferation. Furthermore, since a various range of biochar effects contributes to the control of foliar fungal pathogens through modification of root exudates, soil properties, and nutrient availability, which influence the growth of antagonist microorganisms, we present a review of the pathogen-suppressive effects of biochar, and new control strategies suitable for organic schemes can be developed.Publisher PDFPeer reviewe

Cardiovascular risk in a teenage population in Timbío, Colombia

  Introducción: Las enfermedades cardiovasculares se encuentran entre las primeras causas de muerte a nivel mundial y la evidencia científica sugiere que tienen un origen en edades tempranas, por lo que disminuir desde la adolescencia los riesgos que contribuyen a su aparición es indispensable. Objetivo: Determinar riesgo cardiovascular en la población adolescente de una institución educativa de Timbío, Cauca, 2015 – 2016. Metodología: Estudio cuantitativo, descriptivo, observacional y de corte transversal. Muestra: 100 estudiantes (47 mujeres, 53 hombres), de 10 a 19 años de edad. Se evaluaron variables sociodemográficas, antropométricas, fisiológicas, bioquímicas (glicemia), antecedentes personales, familiares, estilos de vida y uso de anticonceptivos orales. Resultados: Se encontró una mayor prevalencia de riesgo cardiovascular en el grupo etario adolescente (15-18 años) con 84.6%; el género femenino presentó más posibilidad de tener riesgo cardiovascular (OR: 2.8, IC 95% 1.17 – 6.87); el 7% afirmó consumir tabaco regularmente y el 12% son fumadores pasivos. Se obtuvo que el 26% ingiere bebidas alcohólicas, con una mayor prevalencia entre las edades de 15 a 18 años (OR: 19.4, IC 95% 2.45 – 48.11); en cuanto a la actividad física el 79% la practicaba de forma extracurricular. Presentar hábitos alimenticios no saludables genera mayor riesgo cardiovascular (OR: 5.57, IC 95% 1.95 – 15.90). El 67% (n= 67) tiene riesgo cardiovascular. Conclusiones: El género femenino, el grupo adolescente (15-18 años), el consumo de bebidas alcohólicas y hábitos alimenticios no saludables, se asocian con una mayor posibilidad de tener riesgo cardiovascular. Se encontró en un gran porcentaje de la población de estudio riesgo cardiovascular.Introduction: Cardiovascular diseases are among the leading causes of death worldwide and scientific evidence suggests that they have an origin at early ages, so that diminishing from adolescence the risks that contribute to its emergence is essential. Objective: To determine cardiovascular risk in the adolescent population of a high school of Timbío, Cauca, 2015 - 2016. Methodology: Quantitative, descriptive, observational and cross-sectional study. Sample: 100 students (47 women, 53 men), from 10 to 19 years old. Sociodemographic, anthropometric, physiological, biochemical variables (glycemia), personal history, family history, lifestyles and use of oral contraceptives were evaluated. Results: A higher prevalence of cardiovascular risk was found in the adolescent age group (15-18 years) with 84.6%; female gender was more likely to have cardiovascular risk (OR: 2.8, 95% CI 1.17 - 6.87); 7% said they use tobacco regularly and 12% are passive smokers. It was obtained that 26% ingested alcoholic beverages, with a higher prevalence between the ages of 15 to 18 years (OR: 19.4, 95% CI 2.45-48.11); In terms of physical activity, 79% practiced it extracurricularly. Presenting unhealthy eating habits generates greater cardiovascular risk (OR: 5.57, 95% CI 1.95 - 15.90). 67% (n = 67) have cardiovascular risk. Conclusions: The female gender, the adolescent group (15-18 years), drink alcoholic beverages and unhealthy eating habits, are associated with a greater possibility of having cardiovascular risk. It was found in a large percentage of the study population cardiovascular risk

Physiology and Pathology of Neuroimmunology: Role of Inflammation in Parkinson’s Disease

Parkinson’s disease (PD) is a neurodegenerative disease that affects 1% of the population aged 65 and over and is the second most common neurodegenerative disease next to Alzheimer’s disease. Interneuronal proteinaceous inclusions called Lewy bodies (LB) and a selective degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNPC) are the main features of PD pathology. The most common clinical manifestations are rigidity, tremor, bradykinesia, postural instability, sleep disorders, alterations in gait, smell, memory, and dementia. Genetic and environmental factors are involved in PD, and, recently, oxidative stress, proteasome-mediated protein degradation, and inflammation have acquired relevance as major mechanisms of neuronal dysfunction. Increased levels of reactive oxygen and nitrogen species in the brain contribute to greater vulnerability of proteins to nitro-oxidative modification and to greater degrees of aggregation. These protein aggregates contain a variety of proteins of which α-synuclein appears to be the main structural component. Interestingly, α-synuclein can be secreted by neuronal cells and may lead the initiation and the maintenance of inflammatory events through the activation of microglia, which contributes to dopaminergic neuron depletion. New evidence also suggests that PD may be the result of an autoimmune response in which the immune cells recognize the neurons as foreign elements and would act against them, causing their death

Variants in toll-like receptor 9 gene influence susceptibility to tuberculosis in a Mexican population

Background: The control of Mycobacterium tuberculosis (Mtb) infection begins with the recognition of mycobacterial structural components by toll like receptors (TLRs) and other pattern recognition receptors. Our objective was to determine the influence of TLRs polymorphisms in the susceptibility to develop tuberculosis (TB) in Amerindian individuals from a rural area of Oaxaca, Mexico with high TB incidence. Methods: We carried out a case–control association community based study, genotyping 12 polymorphisms of TLR2, TLR4, TLR6 and TLR9 genes in 90 patients with confirmed pulmonary TB and 90 unrelated exposed but asymptomatic household contacts. Results: We found a significant increase in the frequency of the allele A of the TLR9 gene polymorphism rs352139 (A>G) in the group of TB patients (g.f. = 0.522) when compared with controls (g.f. = 0.383), (Pcorr = 0.01, OR = 1.75). Under the recessive model (A/G + A/A vs G/G) this polymorphism was also significantly associated with TB (Pcorr = 0.01, OR= 2.37). The association of the SNP rs352139 was statistically significant after adjustment by age, gender and comorbidities by regression logistic analysis (Dominant model: p value = 0.016, OR = 2.31; Additive model: p value = 0.023, OR = 1.68). The haplotype GAA of TLR9 SNPs was also associated with TB susceptibility (Pcorr = 0.02). Differences in the genotype or allele frequencies of TLR2, TLR4 and TLR6 polymorphisms between TB patients and healthy contacts were not detected. Conclusions: Our study suggests that the allele A of the intronic polymorphism rs352139 on TLR9 gene might contribute to the risk of developing TB in Mexican Amerindians

Ab-initio approach to the stability and the structural, electronic and magnetic properties of the (001) Znfe₂O₄ surface terminations

We present a Density Functional Theory (DFT) based study of the structural and magnetic properties of the (001) surface of the semiconducting oxide Znfe₂O₄ (spinel structure). The calculations were performed using the DFT based ab initio plane wave and pseudopotential method as implemented in the Quantum Espresso code. The all electron Full-potential linearized-augmented-plane-wave method (FP-LAPW) was also employed to check the reproducibility of the plane wave method. In both calculations the DFT+U methodology was employed and different (001) surface terminations of Znfe₂O₄ were studied. We find that the surface terminated in Zn is the stable one. For all the (001) surface terminations our calculations predict that the Zn-Fe cationic inversion (antisites), which are defects in bulk Znfe₂O₄, becomes stable and an integral part of the surface. Also, a ferrimagnetic behavior is predicted for the case of anti-sites in the superficial layer. Our results for different properties of the surface of Znfe₂O₄ are compared with those obtained in bulk samples and those reported in the literature.Facultad de Ciencias ExactasInstituto de Física La Plat

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data