1,025 research outputs found

    Control of the pinewood nematode Bursaphelenchus xylophilus by essential oils and extracts obtained from plants: a review.

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    The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a serious threat to forest ecosystems at a global scale. The nematode has become a major quarantine problem due to its capability to completely destroy Pinus spp. trees, with great damage to the wood industry. Controlling the nematode inside a living tree is quite difficult, the techniques used being often ineffective and quite expensive. In the coming years, most chemicals used to control nematodes will be banned and replaced by safer and environmentally friendly products. As so, chemicals naturally produced by plants will play an important role in controlling diseases such as pine wilt. Plants, particularly aromatic ones, are commonly used due to the chemical properties of their secondary metabolites. Among these, essential oils and/or extracts are highly employed and are being tested as possible control of some organisms, like nematodes. Recent publications have evaluated essential oils derived from different plant species as natural nematicides [1; 2], antibacterial [3], anti-fungal [4] as well as insecticidal [5]. Concerning control of the PWN, a significant amount of information on plants tested, results obtained and employed techniques, is available. Our revision has extensively gathered this information, making it easier to search, read and use. It may become useful information for future studies on the subject, since it will be possible to check the plants already tested. Although numbers aren´t definitive, so far, tested plants are distributed amongst 148 families. The extracts or essential oils of plants belonging to the Asteraceae, Lamiaceae and Euphorbiaceae families show promising results on controlling the pinewood nematode

    Impact of splenic artery ligation after major hepatectomy on liver function, regeneration and viability

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    It was reported that prevention of acute portal overpressure in small-for-size livers by inflow modulation results in a better postoperative outcome. The aim is to investigate the impact of portal blood flow reduction by splenic artery ligation after major hepatectomy in a murine model. Forty-eight rats were subjected to an 85% hepatectomy or 85% hepatectomy and splenic artery ligation. Both groups were evaluated at 24, 48, 72 and 120 post-operative hours: liver function, regeneration and viability. All methods and experiments were carried out in accordance with Coimbra University guidelines. Splenic artery ligation produces viability increase after 24 h, induces a relative decrease in oxidative stress during the first 48 hours, allows antioxidant capacity increment after 24 h, which is reflected in a decrease of half-time normalized liver curve at 48 h and at 72 h and in an increase of mitotic index between 48 h and 72 h. Splenic artery ligation combined with 85% hepatectomy in a murine model, allows portal inflow modulation, promoting an increase in hepatocellular viability and regeneration, without impairing the function, probably by inducing a less marked elevation of oxidative stress at first 48 hours

    Observation of Bc+ →j /ψD (∗)K (∗) decays

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    A search for the decays B+c→J/ψD(*)0K+ and B+c→J/ψD(*)+K*0 is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb−1. The decays B+c→J/ψ0K+ and B+c→J/ψD*0K+ are observed for the first time, while first evidence is reported for the B+c→JψD*+K*0 and B+c→J/ψD+K*0 decays. The branching fractions of these decays are determined relative to the B+c→J/ψπ+ decay. The B+c mass is measured, using the J/ψD0K+ final state, to be 6274.28±1.40(stat)±0.32(syst) MeV/c2. This is the most precise single measurement of the B+c mass to date

    Sodium channel slow inactivation interferes with open channel block

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    Mutations in the voltage-gated sodium channel Nav1.7 are linked to inherited pain syndromes such as erythromelalgia (IEM) and paroxysmal extreme pain disorder (PEPD). PEPD mutations impair Nav1.7 fast inactivation and increase persistent currents. PEPD mutations also increase resurgent currents, which involve the voltage-dependent release of an open channel blocker. In contrast, IEM mutations, whenever tested, leave resurgent currents unchanged. Accordingly, the IEM deletion mutation L955 (ΔL955) fails to produce resurgent currents despite enhanced persistent currents, which have hitherto been considered a prerequisite for resurgent currents. Additionally, ΔL955 exhibits a prominent enhancement of slow inactivation (SI). We introduced mutations into Nav1.7 and Nav1.6 that either enhance or impair SI in order to investigate their effects on resurgent currents. Our results show that enhanced SI is accompanied by impaired resurgent currents, which suggests that SI may interfere with open-channel block

    Advanced load-shift system: an experimental validation of the ac-dc converter as shunt active power filter

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    This paper presents a load-shift system with advanced functionalities to interface the power grid (PG). When compared with the conventional approach, an advanced load-shift system (aLSS) permits the compensation of power quality (PQ) problems for the grid-side, namely problems related to current harmonics, current imbalance, and power factor. The proposed aLSS is composed by a bidirectional ac-dc converter to interface the PG and by a bidirectional dc-dc converter to interface an energy storage system (ESS). Since the main innovation is related with the PG interface, the focus of this work is on the analysis of the ac-dc converter, which is based on a three-phase four-leg converter. A theoretical study and the details concerning the control algorithm are presented and discussed along the paper. A laboratory prototype of the proposed aLSS was developed and the details of implementation are described in the paper. Experimental results obtained with the developed prototype prove that the aLSS contributes for the technology progress in this area, validating a new concept of operation concerning the PQ on the PG side.This work has been supported by FCT – Fundação para a Ciência e Tecnologia with-in the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project QUALITY4POWER PTDC/EEI-EEE/28813/2017, and by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017

    Does Foreign Direct Investment Stimulate New Firm Creation? In Search of Spillovers through Industrial and Geographical Linkages

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    This paper examines the spillover effects of inward foreign direct investment (FDI) on the entrepreneurial activities of new firm creation through both industrial and geographical linkages. Using a dataset of 44,434 newly created small firms in 234 regions of South Korea in 2000–2004, this study finds that while the spillover impacts of FDI in the low-tech industry are positive and significant across almost all four possible combinations of the intra-/inter-regional and intra-/inter-sectoral channels, the impacts in the high-tech industry are largely intra-sectoral within the host region and across neighboring regions. Moreover, all statistically significant spillover effects follow an inverted ‘U’-shaped curvilinear trend

    A genetic cause of Alzheimer disease: mechanistic insights from Down syndrome

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    Down syndrome, caused by an extra copy of chromosome 21, is associated with a greatly increased risk of early onset Alzheimer disease. It is thought that this risk is conferred by the presence of three copies of the gene encoding amyloid precursor protein (APP), an Alzheimer risk factor, although the possession of extra copies of other chromosome 21 genes may also play a role. Further study of the mechanisms underlying the development of Alzheimer disease in Down syndrome could provide insights into the mechanisms that cause dementia in the general population
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