Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
J Appl Microbiol ; 130(4): 1285-1293, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32969574

RESUMEN

AIMS: This work aimed to identify secondary metabolites from aerial parts of Euphorbia species functional for control of toxigenic Fusarium species responsible of cereal grain rots. METHODS AND RESULTS: Aerial parts of Euphorbia serpens, Euphorbia schickendantzii and Euphorbia collina were sequentially extracted with hexane, ethyl acetate and methanol. The extracts were tested against strains of Fusarium verticillioides and Fusarium graminearum by microdilution tests. The hexane extract of E. collina provided the lowest IC50 s on both fungal species. Further fractionation showed that cycloartenol (CA) and 24-methylenecycloartanol are associated to the moderate inhibitory effect of the hexane extract on fungal growth.Sublethal concentrations of CA and 24MCA blocked deoxynivalenol (DON) and fumonisins production.CA and 24MCA co-applied with potassium sorbate, a food preservative used for Fusarium control, synergized the growth inhibition of fungi. The mixtures reduced mycotoxins accumulation when applied at sublethal concentrations. CONCLUSIONS: CA and 24MCA inhibited both fungal growth and mycotoxins production. This fact is an advantage respect to potassium sorbate which increased the mycotoxins accumulation at sublethal concentrations. SIGNIFICANCE AND IMPACT OF THE STUDY: CA and 24MCA synergized potassium sorbate and their mixtures offer a lower mycotoxigenic risk than potassium sorbate for control of the Fusarium species.


Asunto(s)
Antifúngicos/farmacología , Grano Comestible/microbiología , Euphorbia/química , Extractos Vegetales/farmacología , Euphorbia/clasificación , Conservantes de Alimentos/farmacología , Fumonisinas/metabolismo , Fusarium/efectos de los fármacos , Fusarium/crecimiento & desarrollo , Fusarium/metabolismo , Micotoxinas/metabolismo , Metabolismo Secundario
2.
Sci Rep ; 13(1): 11114, 2023 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-37429877

RESUMEN

Magnesium alloys, among the lightest structural materials, represent excellent candidates for lightweight applications. However, industrial applications remain limited due to relatively low strength and ductility. Solid solution alloying has been shown to enhance Mg ductility and formability at relatively low concentrations. Zn solutes are significantly cost effective and common. However, the intrinsic mechanisms by which the addition of solutes leads to ductility improvement remain controversial. Here, by using a high throughput analysis of intragranular characteristics through data science approaches, we study the evolution of dislocation density in polycrystalline Mg and also, Mg-Zn alloys. We apply machine learning techniques in comparing electron back-scatter diffraction (EBSD) images of the samples before/after alloying and before/after deformation to extract the strain history of individual grains, and to predict the dislocation density level after alloying and after deformation. Our results are promising given that moderate predictions (coefficient of determination [Formula: see text] ranging from 0.25 to 0.32) are achieved already with a relatively small dataset ([Formula: see text] 5000 sub-millimeter grains).

3.
AJNR Am J Neuroradiol ; 43(4): 547-553, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35332023

RESUMEN

BACKGROUND AND PURPOSE: Many small, regularly shaped cerebral aneurysms rupture; however, they usually receive a low score based on current risk-assessment methods. Our goal was to identify patient and aneurysm characteristics associated with rupture of small, regularly shaped aneurysms and to develop and validate predictive models of rupture in this aneurysm subpopulation. MATERIALS AND METHODS: Cross-sectional data from 1079 aneurysms smaller than 7 mm with regular shapes (without blebs) were used to train predictive models for aneurysm rupture using machine learning methods. These models were based on the patient population, aneurysm location, and hemodynamic and geometric characteristics derived from image-based computational fluid dynamics models. An independent data set with 102 small, regularly shaped aneurysms was used for validation. RESULTS: Adverse hemodynamic environments characterized by strong, concentrated inflow jets, high speed, complex and unstable flow patterns, and concentrated, oscillatory, and heterogeneous wall shear stress patterns were associated with rupture in small, regularly shaped aneurysms. Additionally, ruptured aneurysms were larger and more elongated than unruptured aneurysms in this subset. A total of 5 hemodynamic and 6 geometric parameters along with aneurysm location, multiplicity, and morphology, were used as predictive variables. The best machine learning rupture prediction-model achieved a good performance with an area under the curve of 0.84 on the external validation data set. CONCLUSIONS: This study demonstrated the potential of using predictive machine learning models based on aneurysm-specific hemodynamic, geometric, and anatomic characteristics for identifying small, regularly shaped aneurysms prone to rupture.


Asunto(s)
Aneurisma Roto , Aneurisma Intracraneal , Aneurisma Roto/diagnóstico por imagen , Angiografía Cerebral , Estudios Transversales , Hemodinámica , Humanos , Hidrodinámica , Aneurisma Intracraneal/diagnóstico por imagen , Factores de Riesgo
4.
AJNR Am J Neuroradiol ; 39(10): 1860-1866, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30166431

RESUMEN

BACKGROUND AND PURPOSE: Hostile hemodynamic conditions and geometries are thought to predispose aneurysms for instability and rupture. This study compares stable, unstable, and ruptured aneurysms while controlling for location and patient characteristics. MATERIALS AND METHODS: The hemodynamics and geometries of 165 stable, 65 unstable, and 554 ruptured aneurysms were compared. Hemodynamics was modeled using image-based computational fluid dynamics. Case-control pairs were selected matching aneurysm location, patient age, and sex. Paired Wilcoxon tests were used to compare hemodynamic and geometric variables among different aneurysm groups. The pairing was repeated 100 times, and the combined P values were calculated and adjusted for multiple testing. RESULTS: Ruptured aneurysms had lower minimum wall shear stress (P = .03), higher maximum wall shear stress (P = .03), more concentrated (P = .03) and mean oscillatory shear stress (P = .03), higher maximum velocity (P = .03), and more complex flows (vortex core-line length, P = .03) than stable aneurysms. Similarly, unstable aneurysms had more concentrated shear stress (P = .04) and more complex flows (vortex core-line length, P = .04) than stable aneurysms. Compared with stable aneurysms, ruptured aneurysms were larger (size ratio, aneurysm size/vessel size, P = .03), more elongated (aspect ratio, P = .03), and irregular (nonsphericity index, P = .03). Similarly, unstable aneurysms were larger (size ratio, P = .04), more elongated (aspect ratio, P = .04), and irregular (bulge location, P = .04; area-weighted Gaussian curvature; P = .04) than stable aneurysms. No significant differences were found between unstable and ruptured aneurysms. CONCLUSIONS: Unstable and ruptured aneurysms have more complex flows with concentrated wall shear stress and are larger, more elongated, and irregular than stable aneurysms, independent of aneurysm location and patient sex and age.


Asunto(s)
Aneurisma Roto/patología , Aneurisma Roto/fisiopatología , Aneurisma Intracraneal/patología , Aneurisma Intracraneal/fisiopatología , Adulto , Anciano , Estudios de Casos y Controles , Simulación por Computador , Femenino , Hemodinámica/fisiología , Humanos , Hidrodinámica , Masculino , Persona de Mediana Edad , Factores de Riesgo , Estrés Mecánico
5.
AJNR Am J Neuroradiol ; 38(12): 2301-2307, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28982787

RESUMEN

BACKGROUND AND PURPOSE: Different hemodynamic patterns have been associated with aneurysm rupture. The objective was to test whether hemodynamic characteristics of the ruptured aneurysm in patients with multiple aneurysms were different from those in unruptured aneurysms in the same patient. MATERIALS AND METHODS: Twenty-four mirror and 58 ipsilateral multiple aneurysms with 1 ruptured and the others unruptured were studied. Computational fluid dynamics models were created from 3D angiographies. Case-control studies of mirror and ipsilateral aneurysms were performed with paired Wilcoxon tests. RESULTS: In mirror pairs, the ruptured aneurysm had more oscillatory wall shear stress (P = .007) than the unruptured one and tended to be more elongated (higher aspect ratio), though this trend achieved only marginal significance (P = .03, 1-sided test). In ipsilateral aneurysms, ruptured aneurysms had larger maximum wall shear (P = .05), more concentrated (P < .001) and oscillatory wall shear stress (P < .001), stronger (P < .001) and more concentrated inflow jets (P < .001), larger maximum velocity (P < .001), and more complex flow patterns (P < .001) compared with unruptured aneurysms. Additionally, ruptured aneurysms were larger (P < .001) and more elongated (P < .001) and had wider necks (P < .001) and lower minimum wall shear stress (P < .001) than unruptured aneurysms. CONCLUSIONS: High wall shear stress oscillations and larger aspect ratios are associated with rupture in mirror aneurysms. Adverse flow conditions characterized by high and concentrated inflow jets; high, concentrated, and oscillatory wall shear stress; and strong, complex and unstable flow patterns are associated with rupture in ipsilateral multiple aneurysms. In multiple ipsilateral aneurysms, these unfavorable flow conditions are more likely to develop in larger, more elongated, more wide-necked, and more distal aneurysms.


Asunto(s)
Aneurisma Roto/fisiopatología , Hemodinámica/fisiología , Aneurisma Intracraneal/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Simulación por Computador , Femenino , Humanos , Hidrodinámica , Masculino , Persona de Mediana Edad , Factores de Riesgo
6.
AJNR Am J Neuroradiol ; 38(11): 2111-2118, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28860212

RESUMEN

BACKGROUND AND PURPOSE: Intracranial aneurysms originating at the posterior communicating artery are known to have high rupture risk compared with other locations. We tested the hypothesis that different angioarchitectures (ie, branch point configuration) of posterior communicating artery aneurysms are associated with aneurysm hemodynamics, which in turn predisposes aneurysms to rupture. MATERIALS AND METHODS: A total of 313 posterior communicating artery aneurysms (145 ruptured, 168 unruptured) were studied with image-based computational fluid dynamics. Aneurysms were classified into different angioarchitecture types depending on the location of the aneurysm with respect to parent artery bifurcation. Hemodynamic characteristics were compared between ruptured and unruptured aneurysms, as well as among aneurysms with different angioarchitectures. RESULTS: Angioarchitecture was associated with rupture (P = .003). Ruptured aneurysms had higher, more concentrated, and more oscillatory wall shear stress distributions (maximum wall shear stress, P < .001; shear concentration index, P < .001; mean oscillatory shear index, P < .001), stronger and more concentrated inflow jets (represented as Q, P = .01; inflow concentration index, P < .001), and more complex and unstable flow patterns (vortex core length, P < .001; proper orthogonal decomposition entropy, P < .001) compared with unruptured aneurysms. These adverse conditions were more common in aneurysms with bifurcation-type angioarchitectures compared with those with lateral or sidewall angioarchitectures. Interestingly, ruptured aneurysms also had lower normalized mean wall shear stress (P = .02) and minimum wall shear stress (P = .002) than unruptured aneurysms. CONCLUSIONS: High-flow intrasaccular hemodynamic characteristics, commonly found in bifurcation-type angioarchitectures, are associated with the posterior communicating artery aneurysm rupture status. These characteristics include strong and concentrated inflow jets, concentrated regions of elevated wall shear stress, oscillatory wall shear stress, lower normalized wall shear stress, and complex and unstable flow patterns.


Asunto(s)
Aneurisma Roto/fisiopatología , Hemodinámica/fisiología , Aneurisma Intracraneal/fisiopatología , Aneurisma Roto/complicaciones , Humanos , Hidrodinámica , Aneurisma Intracraneal/complicaciones , Masculino , Factores de Riesgo , Estrés Mecánico
7.
Clin Pharmacol Ther ; 60(5): 589-92, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8941033

RESUMEN

This case report describes a 69-year-old woman with diabetes mellitus and heart failure who repeatedly had unusual subtherapeutic levels of plasma digoxin. When the drug therapeutic regimen was checked it was found that a new drug, acarbose, had been added to the therapeutic regimen before the unexpected laboratory reported results. Because other drugs included in her therapeutic menu were rejected as being responsible for decreased levels of digoxin, it was recommended to discontinue acarbose to evaluate its role. In the absence of acarbose, the plasma concentration of digoxin increased to the therapeutic range. We concluded that acarbose may be responsible for a pharmacokinetic interaction with digoxin by a still unknown mechanism. Although discontinuation of acarbose was recommended, the attending physician discontinued administration of digoxin because the clinical condition of the patient did not get worse during subtherapeutic levels of digoxin.


Asunto(s)
Cardiotónicos/sangre , Digoxina/sangre , Hipoglucemiantes/farmacología , Trisacáridos/farmacología , Acarbosa , Angina Inestable/tratamiento farmacológico , Cardiotónicos/uso terapéutico , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Digoxina/uso terapéutico , Interacciones Farmacológicas , Quimioterapia Combinada , Femenino , Insuficiencia Cardíaca/tratamiento farmacológico , Humanos , Hipertensión/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Persona de Mediana Edad , Trisacáridos/uso terapéutico
8.
Food Chem ; 141(4): 3546-51, 2013 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-23993519

RESUMEN

A 96-well plate micromethod was developed to measure 5-n-alkylresorcinols (5nARs) in cereal grains and food derived products. The 5nARs reacted in alkaline alcoholic medium with Fast Blue RR ½ZnCl2 salt to yield coloured azo-derivatives. The highest sensitivity for 5nARs was obtained at 490 nm with 0.025% ethanolic Fast Blue RR and 5% K2CO3. This reaction showed good linearity for olivetol (0.05-0.20 µg). Contents of 5nARs determined in cereal grains and derived products by the new Fast Blue RR micromethod were highly correlated (R(2)=0.9944) with those obtained by a Fast Blue B method currently used. A Bland-Altman analysis indicated a small positive bias near to zero (R(2)=0.0401), suggesting that the methods can be interchangeably used. The new reaction is completed in 15 min and the coloured products are read within the 15 min after completion. The micromethod offers a fast analysis of 5nARs in cereal grains and derived products with low consumption of reagents and solvents.


Asunto(s)
Colorimetría/métodos , Grano Comestible/química , Extractos Vegetales/química , Resorcinoles/química , Colorimetría/instrumentación
9.
Rev. chil. pediatr ; 80(5): 451-458, oct. 2009. ilus
Artículo en Español | LILACS | ID: lil-559579

RESUMEN

Poland Syndrome is a rare congenital alteration. It is characterized by hypoplasia or absence of the pectoral muscle, hypoplasia or aplasia of the mammary gland, nipple, ribs or cartilages, and hand malformations. A case is reported of a girl showing these malformations, and neuronal migration abnormalities. Emphasis is made upon the need for a multidisciplinary team for management and rehabilitation. A literature review is presented, including pathogenesis, clinical manifestations and treatment.


El Síndrome de Poland es una alteración congénita de baja frecuencia y de carácter esporádico. Se caracteriza por ausencia o hipoplasia del músculo pectoral; hipoplasia o aplasia de glándula mamaria, pezón, costillas o cartílagos, y malformaciones de la mano. Se reporta el caso de una recién nacida con Secuencia de Poland con trastorno de migración neuronal. Se hace énfasis en la necesidad de un equipo multidisciplinario en su manejo y rehabilitación. Se presenta una revisión de la literatura con especial énfasis en la patogenia, manifestaciones clínicas y tratamiento.


Asunto(s)
Humanos , Femenino , Recién Nacido , Síndrome de Poland/diagnóstico , Síndrome de Poland/etiología , Síndrome de Poland/terapia , Movimiento Celular , Ectromelia
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA