2,390 research outputs found
Controle da podridão cinzenta da maçã por produtos naturais biologicamente ativos
Indexación: Web of Science; ScieloBiorend SC (chitosan), BC-1000 EC (grapefruit extract plus bioflavonoids) and ECO-100 SC (bioflavonoids plus organic acids, citric phytoalexins, fatty acids, glycerides and sugars), respectively, suppressed grey rot of apple caused by B. cinerea by 80.1%, 79.0% and 76.5% when used as post-harvest treatments under controlled conditions. When applied as combined pre- and post-harvest treatments Biorend SC inhibited fruit rot by 49.9 %, while BC-1000 EC and ECO-100 SC were ineffective. None of the products inhibited fruit rot when applied as pre-harvest treatments under controlled conditions or as post-harvest treatments under commercial conditions. The algal polysaccharide ulvan used in post-harvest treatments suppressed grey rot by 56.0% under controlled conditions, but had no inhibitory effect on combined pre- and post-harvest treatments. The inability of products to activate defense mechanisms (chitinase and peroxidase) of fruits was consistent with the unsuccessful control of rot by pre-harvest treatment. The results suggest that the natural products used have potential for use in integrated management of Botrytis rot when applied after harvest.Biorend SC (quitosana), BC-1000 EC (extrato de toranja mais flavonóides), e ECO-100 SC (bioflavonóides mais ácidos orgânicos, fitoalexinas cítricas, ácidos graxos glicerídeos e açúcares) inibiram em 80,1%, 79,0% e 76,5%, respectivamente, a podridão causada por Botrytis cinerea quando utilizados no tratamento pós-colheita de frutos de maçã sob condições controladas.Tratamento combinado de Biorend SC, com aplicação tanto em pré como no pós-colheita, proporcionou 49,9% de inibição da podridão, enquanto BC-1000 e ECO-100 EC não foram efetivos. Nenhum desses produtos inibiu a podridão cinzenta, quando utilizados em tratamento de pré-colheita em condições controladas ou em tratamento de pós-colheita em condições comerciais. O polissacarídeo algal ulvana, utilizado nos tratamentos de pós-colheita, reduziu em 56% a podridão cinzenta das maçãs em condições controladas, mas não teve efeito inibitório nos tratamentos combinados de pré e pós-colheita. A incapacidade dos produtos em ativar mecanismos de defesa (quitinases e peroxidases) nos frutos, após o tratamento em pré-colheita, foi consistente com a falta de controle da podridão nesse tipo de ensaio. Pelos resultados, sugere-se que os produtos naturais utilizados apresentam potencial para a utilização no manejo integrado da podridão de Botrytis quando aplicados em pós-colheita.http://ref.scielo.org/kcxb9
Regular and complex singularities of the generalized thin film equation in two dimensions
A20We use a generalized version of the equation of motion for a thin film of liquid on a solid,
horizontal substrate as a model system to study the formation of singularities in space
dimensions greater than one. Varying both the exponent controlling long-ranged forces, as
well as the exponent of the nonlinear mobility, we predict the structure of the singularity
as the film thickness goes to zero. The spatial structure of rupture may be either ‘pointlike’
(approaching axisymmetry) or ‘quasi-one-dimensional’, in which case a one-dimensional
singularity is unfolded into two or higher space dimensions. The scaling of the profile with
time may be either strictly self-similar (the ‘regular’ case) or discretely self-similar and
perhaps chaotic (the ‘irregular’ case). We calculate the phase boundaries between these
regimes, and confirm our results by detailed comparisons with time-dependent simulations
of the nonlinear thin film equation in two space dimensions.Junta de Andalucía P18-FR-3623Ministerio de Economía y Competitividad (MINECO). España 108278-RB-C3
Angular dependence of the artificially induced anistropy in α-axis-oriented EuBa_2Cu_3O_7/PrBa_2Cu_3O_7 superconducting superlattices
α-axis-oriented EuBa_2Cu_3O_7/PrBa_2Cu_3O_7 (EBCO/PBCO) superlattices allow us to separate contributions to the anisotropy coming from the natural layered structure of EBCO from that introduced by the artificial layering with PBCO. The angular dependence of the critical current and resistivity in a magnetic field has been studied with different superlattice modulation lengths (strong coupling regime). The increase in the insulating PBCO layer thickness produces a crossover from an a-axis-oriented three-dimensional (3D) superconductor with a distribution of planar pinning centers to a 3D superconductor with an angular anisotropy behavior similar to single-phase c-axis-oriented films
Awareness, treatment and control of hypertension: Trend from population-based surveys conducted in a low-middle income country
Aim: To estimate and determine temporal trends for awareness, treatment and control of hypertension in adults from the urban area in Colombia. Methods: We conducted two population-based surveys (years 2010 and 2015) in the Metropolitan Area of Bucaramanga-Santander, Colombia, using the WHO STEPwise approach. Participants were asked to provide demographic, socioeconomic and cardiovascular risk factors data. Blood pressure (BP) was measured twice using an automated device. Hypertension was defined as a systolic BP≥140 mmHg, a diastolic BP≥90 mmHg or self-reported antihypertensive treatment. We estimated age, sex, and socioeconomic status (SES) adjusted prevalence ratios (PR), with 2010 as the reference survey, using poisson regression and correcting standard errors by clustering. Results: We evaluated 1,136 (mean age: 35.7 years; 43% male) and 872 (mean age:37.7 years; 41% male) adults from the 2010 and 2015 surveys, respectively. There were a larger proportion of individuals sampled from low SES in the 2015 as compared to the 2010 survey (93.6% vs. 70.9%). Overall, prevalence of hypertension was 16.4% (95%CI: 14.8 – 17.9): It increased significantly with age (from 2.4% among individuals 15-19 years old to 41.1% among individuals 50 years and older; p-trend<0.001) but did not differed by sex (17.8% in men vs. 15.4% in women) or year (16.1% vs. 16.6% in 2010 and 2015, respectively). Overall, prevalence of awareness, treatment and control of hypertension were 65.0%, 84.1%, and 62.2%, respectively. Although awareness and control increased from 2010 to 2015 (PR=1.05 and PR=1.12, respectively), only the prevalence of treatment showed a statistically significant increment of 11% (PR=1.11; 95%IC: 1.01 – 1.24). Implication: The STEPwise is a suitable surveillance strategy to estimate the burden of cardiovascular risk factors in low-middle income countries. Our results are consistent with national data from urban areas and show for the first time a short-time improvement in antihypertensive coverage
Adaptive Bone Remodeling With New Design of the ABG Stem. Densitometric Study
To establish the pattern of bone remodeling caused by a cementless, anatomic implant, we intend to evaluate the changes in bone mineral density observed after surgery in the Gruen zones. A controlled, prospective study was carried out, in which a group of 37 patients with primary coxarthrosis were densitrometrically analyzed over the 1 year period following the implant of an ANATO stem (Stryker). The patient's healthy hip was taken as the control. Any differences in the remodeling pattern were compared according to age, body mass index, and implant size. Decreases in bone mineral density were observed after 3 months in all of the zones studied. However, this bone mineral density loss was recovered in all zones by the end of the study, except in zone 7 where a decrease of 7.2% in bone mass was observed. In zones 2 and 6, where more loads are transmitted, bone mass preservation, in accordance with Wolff's law, can be seen. No differences were found in the remodeling pattern in relation to age and body mass index. There were also no differences related to stem size except in zones 1 and 7. The ANATO stem achieves an efficient transmission of loads between the stem and the proximal femur, providing enough mechanical loads for bone preservation. It is only in zone 7 where significant bone atrophy can be observed, attributable to the damage that this area suffers during the surgical process and the subsequent stress-shielding caused by the implant design
Experimental vortex ratchet effect in nanostructured superconductors
Superconducting Nb thin films were grown on different arrays of triangle-shape metallic islands. The vortex lattice dynamics could be strongly modified by these asymmetric vortex traps. These asymmetric pinning potentials lead to a rectification effect on the vortex motion: Injecting an ac supercurrent on the sample yields a net dc vortex flow. This vortex ratchet ffect is adiabatic and reversible: The effect is frequency independent and the polarity of the dc voltage output could be tuned by the applied magnetic fields and the input ac currents
Vortex-lattice dynamics with channeled pinning potential landscapes
We have studied vortex-lattice dynamics as a function of driving force direction, in superconducting Nb films with periodic pinning arrays of magnetic dots. Square and rectangular symmetry arrays define channels that guide the vortex-lattice motion. We investigated the effect of the driving force direction on the commensurability between the vortex-lattice and dots array. We also studied the transverse depinning of the vortex-lattice as is moving longitudinally along channels. We found that transverse depinning forces are enhanced with respect to the static situation. The results are discussed in terms of the dynamical evolution of order in the vortex-lattice
Magnetic properties of Ni nanoparticles dispersed in silica prepared by high-energy ball milling
We analyze the magnetic properties of mechanically ground nanosized Ni particles dispersed in a SiO_2 matrix. Our magnetic characterization of the as-milled samples show the occurrence of two blocking processes and that of non-monotonic milling time evolutions of the magnetic-order temperature, the high-field magnetization and the saturation coercivity. The measured coercivities exhibit giant values and a uniaxial- type temperature dependence. Thermal treatment carried out in the as-prepared samples result in a remarkable coercivity reduction and in an increase of the high-field magnetization. We conclude, on the basis of the consideration of a core (pure Ni) and shell (Ni-Si inhomogeneous alloy) particle structure, that the magnetoelastic anisotropy plays the dominant role in determining the magnetic properties of our particles
Experimental adiabatic vortex ratchet effect in Nb films with asymmetric pinning trap
Nb films grown on top of an array of asymmetric pinning centers show a vortex ratchet effect. A net flow of vortices is induced when the vortex lattice is driven by fluctuating forces on an array of pinning centers without reflection symmetry. This effect occurs in the adiabatic regime and it could be mimiced only by reversible DC driven forces
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