4,725 research outputs found

    Acantholippia salsoloides : Phytochemical Composition and Biological Potential of a Thujonic Population

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    Acantholippia salsoloides (Verbenaceae) is an aromatic plant widespread in the Andean region. The infusion (leaves and flowers) is widely used as a digestive stimulant as well as for the treatment of various diseases in traditional medicine. A. salsoloides attributes its common name “rica-rica” to the fresh and sweet fragrance of the plant. In this work, 2 different polar extracts and the essential oil of a selected rica-rica population were studied. The phenolic composition was analyzed by high-performance liquid chromatography diode array detector; the essential oil profile was determined by gas-chromatography ion-trap mass spectrometry/flame ionization detection. For all extracts, the antibacterial potential was performed by in vitro assays; the antioxidant and α-glucosidase inhibition were determined in decoction and hydroethanolic extracts. The volatile profile allowed the identification of 26 volatile compounds, ÎČ-thujone (84%) being the major one in this rica-rica population. Eighteen phenolic compounds were identified; isoferulic acid (16%-18%) and cynaroside (45%-47%) were the larger ones. In a general way, the hydroethanolic extract was more active against Staphylococcus aureus and Micrococcus luteus (minimum inhibitory concentrations= 0.3- 1.3 mg/mL). Both polar extracts have strong antiradical activities although decoction extract proved to be more active against DPPH· (half-maximal inhibitory concentration [IC50] =36 ”g/mL) and O2‱− (IC50 =28 ”g/mL) while hydroethanolic extract shows higher action over α-glucosidase (IC50 =217 ”g/mL). The results suggest that A. salsoloides leaves and flowers may be an interesting source of natural antioxidants, antidiabetics, or antimicrobials, and could be used in dietary supplements, medicinal products and pharmaceutical formulations.Fil: Celaya, Liliana Soledad. Universidad Nacional de Jujuy. Centro Interdisciplinario de Investigaciones En Tecnologias y Desarrollo Social Para El Noa. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Saltajujuy. Centro Interdisciplinario de Investigaciones En Tecnologias y Desarrollo Social Para El Noa.; Argentina. Universidad Nacional de Misiones; ArgentinaFil: Viturro, Carmen Ines. Universidad Nacional de Jujuy. Centro Interdisciplinario de Investigaciones En Tecnologias y Desarrollo Social Para El Noa. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Saltajujuy. Centro Interdisciplinario de Investigaciones En Tecnologias y Desarrollo Social Para El Noa.; Argentina. Universidad Nacional de Jujuy; ArgentinaFil: Silva, LuĂ­s R.. Universidade da Beira Interior; Portuga

    Event-related brain potentials in the study of inhibition: cognitive control, source localization and age-related modulations

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    In the previous 15 years, a variety of experimental paradigms and methods have been employed to study inhibition. In the current review, we analyze studies that have used the high temporal resolution of the event-related potential (ERP) technique to identify the temporal course of inhibition to understand the various processes that contribute to inhibition. ERP studies with a focus on normal aging are specifically analyzed because they contribute to a deeper understanding of inhibition. Three time windows are proposed to organize the ERP data collected using inhibition paradigms: the 200 ms period following stimulus onset; the period between 200 and 400 ms after stimulus onset; and the period between 400 and 800 ms after stimulus onset. In the first 200 ms, ERP inhibition research has primarily focused on N1 and P1 as the ERP components associated with inhibition. The inhibitory processing in the second time window has been associated with the N2 and P3 ERP components. Finally, in the third time window, inhibition has primarily been associated with the N400 and N450 ERP components. Source localization studies are analyzed to examine the association between the inhibition processes that are indexed by the ERP components and their functional brain areas. Inhibition can be organized in a complex functional structure that is not constrained to a specific time point but, rather, extends its activity through different time windows. This review characterizes inhibition as a set of processes rather than a unitary process

    Synchronized stationary clouds in a static fluid

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    The existence of stationary bound states for the hydrodynamic velocity field between two concentric cylinders is established. We argue that rotational motion, together with a trapping mechanism for the associated field, is sufficient to mitigate energy dissipation between the cylinders, thus allowing the existence of infinitely long lived modes, which we dub stationary clouds. We demonstrate the existence of such stationary clouds for sound and surface waves when the fluid is static and the internal cylinder rotates with constant angular velocity Ω\Omega. These setups provide a unique opportunity for the first experimental observation of synchronized stationary clouds. As in the case of bosonic fields around rotating black holes and black hole analogues, the existence of these clouds relies on a synchronization condition between Ω\Omega and the angular phase velocity of the cloud.Comment: v2: 7 pages, 4 figures. Accepted for publication in Physics Letters

    Thin waveguides with Robin boundary conditions

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    We consider the Laplace operator in a thin three dimensional tube with a Robin type condition on its boundary and study, asymptotically, the spectrum of such operator as the diameter of the tube's cross section becomes infinitesimal. In contrast with the Dirichlet condition case, we evidence different behaviors depending on a symmetry criterium for the fundamental mode in the cross section. If that symmetry condition fails, then we prove the localization of lower energy levels in the vicinity of the minimum point of a suitable function on the tube's axis depending on the curvature and the rotation angle. In the symmetric case, the behavior of lower energy modes is shown to be ruled by a one dimensional Sturm-Liouville problem involving an effective potential given in explicit form

    Teachable Moments: oportunidades a nĂŁo perder

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    Neste texto começamos por analisar um episódio ao nível das açÔes desencadeadas por uma professora e do conhecimento didåtico que as suporta. Depois, analisamos a forma como futuros professores de Matemåtica, a iniciarem o seu mestrado profissionalizante entendem o episódio, do ponto de vista matemåtico e do ponto de vista da gestão da aula. Finalmente, terminamos com algumas questÔes para a formação de professores que decorrem desta anålise

    NEETs in a rural region of Southern Europe: perceived self-efficacy, perceived barriers, educational expectations, and vocational expectations

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    The aim of this research is to understand the influence of demographic and professional experience factors on the self-efficacy and perceived barriers of rural Portuguese youths not in employment, education or training (NEET), as well as on their educational and vocational expectations at age 35. These indicators are involved in the compromise mechanism of choice of the circumscription and compromise theory, a construct that describes the reason why certain vocational alternatives are progressively restricted among young adults. Most of the participants (n?=?137) were female (62%) and their age ranged from 18 to 30 (M?=?24.88; SD?=?2.30). Findings show that the participants' self-efficacy was positively affected by having a previous job contract, and negatively influenced by longer unemployment periods (>24 months). Longer unemployment periods also increase the perception of barriers. Educational expectations at age 35 were significantly higher among participants who had completed middle school and marginally lower for those living with their parents, while vocational expectations at age 35 were more conservative among those who had concluded high school. Recommendations are made regarding employment policies as well as training and vocational guidance interventions for NEETs in rural regions

    Metabolic dysfunction biomarkers as predictors of early diabetes

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    During the pathophysiological course of type 2 diabetes (T2D), several metabolic imbalances occur. There is increasing evidence that metabolic dysfunction far precedes clinical manifestations. Thus, knowing and understanding metabolic imbalances is crucial to unraveling new strategies and molecules (biomarkers) for the early-stage prediction of the disease’s non-clinical phase. Lifestyle interventions must be made with considerable involvement of clinicians, and it should be considered that not all patients will respond in the same manner. Individuals with a high risk of diabetic progression will present compensatory metabolic mechanisms, translated into metabolic biomarkers that will therefore show potential predictive value to differentiate between progressors/non-progressors in T2D. Specific novel biomarkers are being proposed to entrap prediabetes and target progressors to achieve better outcomes. This study provides a review of the latest relevant biomarkers in prediabetes. A search for articles published between 2011 and 2021 was conducted; duplicates were removed, and inclusion criteria were applied. From the 29 studies considered, a survey of the most cited (relevant) biomarkers was conducted and further discussed in the two main identified fields: metabolomics, and miRNA studies.This research was funded by the FCT - Fundação para a CiĂȘncia e Tecnologia (REF UID/BIM/04293/2019), and by the following scholarships: (Ref. SAICT2016/FEDER/BIO4DIA/BTI) and (SFRH/BD/146489/2019)
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