521 research outputs found

    Ovarian development and analysis of mating effects on ovary maturation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

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    As many other insects with a restricted diet, the citrus psyllid Diaphorina citri Kuwayama, which vector the causing agent of the Huanglongbing, the bacteria Candidatus Liberibacter spp., is intimately associated with symbiotic microorganisms. These mutualist symbionts play a key role on their host nutritional ecology, and are vertically transmitted to the progeny. However, despite the role symbionts play on host development and reproduction, and the growing opportunities of exploitation of the association insect-symbiont to control insect vectored-pathogens, there are very few studies on the host reproductive biology and on the symbiont transovarial transmission. Therefore, we aimed at analyzing the ovary development during D. citri adulthood, and at verifying for the mating requirement as a trigger to initiate ovary development. Newly-emerged D. citri females were grouped as virgin or mated and ovary development was observed during adulthood. Newly-emerged females have immature ovaries, and ovaries remain without any mature eggs until females mate. Once female mates, the vitellogenesis synthesis and uptake are estimulated, and oocytes are quickly developed. Oocytes maturation in ovarioles is metachronic, with only one oocyte developing at a time in each oogenic cycle. Morphological observations of the reproductive system including the ovaries and spermatheca, after the first cluster of eggs is laid, indicated D. citri is polyandrous, and may require multiple mating to develop additional oogenic maturation cycles.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Overview about E-Mobility Conducted Immunity Tests on ESA Communication Lines

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    Due to the complexity of the Automotive Electromagnetic Compatibility legislation in force, this article aims to describe a simplified overview of several technical standards relating to conducted immunity tests on electronic sub-assemblies, where communication lines are involved. The discussed automotive standards reported in this article are: ISO 11452-1 and ISO 11452-4 for continuous narrowband electromagnetic fields immunity test, bulk current injection and tubular wave coupler, IEC 61000-4-5 for immunity against surge events, IEC 61000-4-4 for electrical fast transient/burst events immunity, ISO 10605 for electrostatic discharge events immunity, ISO 7637-2 and ISO 7637-3 for transient disturbances events immunity. For each cited standard, disturbance bandwidth evaluation was performed. Practical examples are reported, with analysis and discussion of some of the adoptable disturbance countermeasures applicable on controlled area network communication lines, and possible design advantages and disadvantages with different types of filtering and suppression circuit solutions

    n-3 AGPICL en la reversión de la esteatosis hepática: el papel de la ACOX y CAT

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    The aim of this study was to investigate the roles of the Acyl co-enzyme A oxidase (ACOX), carnitine acyl transferase I (CAT-1) and activating protein 1 (AP-1) in the reversal of hepatic steatosis with dietary change and n-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation. Male C57BL/6J mice were given either a control diet (CD) or a high fat diet (HFD) for 12 weeks, and then continued with the CD or CD plus n-3 LCPUFA for eight weeks. After this period, body and adipose visceral tissue weight were analyzed and liver samples were taken to measure ACOX, CAT-1 and c-jun levels. The dietary change from HFD to a norm caloric diet plus n-3 LCPUFA supplementation significantly reduced liver steatosis and adipose tissue: body weight ratio, along with an increase in the hepatic ACOX and CAT-1 levels and normalization of AP-1 expression that could favor the fatty acid beta-oxidation over lipogenesis and regulate inflammation. These results provide new data on the enzymatic metabolism underlying dietary change to a norm caloric diet plus n-3 LCPUFA supplementation.El objetivo de este estudio fue investigar el rol de las enzimas Acil coenzima A oxidasa (ACOX) y Acil carnitina transferasa 1 (CAT-1), además del factor de transcripción, Proteína activadora 1 (AP-1) en la reversión de la esteatosis hepática mediante cambio de dieta más suplementación con Ácidos grasos poliinsaturados de cadena larga omega tres (AGPICL n-3). Ratones macho de la cepa C57BL/6J fueron alimentados con dieta control (DC) o alta en grasas (DAG) durante 12 semanas, luego continuaron con DC con o sin suplementación de AGPICL n-3 durante 8 semanas. Después de este período, se analizó el peso corporal y del tejido adiposo visceral; en las muestras hepáticas se evaluaron los niveles de ACOX, CAT-1 y AP-1. El cambio a dieta control más suplementación con AGPICL n-3 reduce significativamente la esteatosis hepática y la relación tejido adiposo/peso corporal, acompañado de un incremento en los niveles hepáticos de ACOX y CAT-1 y normalización de la expresión de AP-1; regulando la inflamación y favoreciendo la beta oxidación sobre la lipogénesis. Estos resultados proveen nuevos datos sobre el metabolismo enzimático cuando se realiza cambio a dieta control más suplementación con AGPICL n-3

    How to clean and safely remove HF from acid digestion solutions for ultra-trace analysis: a microwave-assisted vessel-inside-vessel protocol

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    The complete dissolution of silicate-containing materials, often necessary for elemental determination, is generally performed by microwave-assisted digestion involving the forced use of hydrofluoric acid (HF). Although highly efficient in dissolving silicates, this acid exhibits many detrimental effects (e.g., formation of precipitates, corrosiveness to glassware) that make its removal after digestion essential. The displacement of HF is normally achieved by evaporation in open-vessel systems: atmospheric contamination or loss of analytes can occur when fuming-off HF owing to the non-ultraclean conditions necessarily adopted for safety reasons. This aspect strongly hinders determination at the ultra-trace level. To overcome this issue, we propose a clean and safe microwaveassisted procedure to induce the evaporative migration of HF inside a sealed \u201cvessel-inside-vessel\u201d system: up to 99.9% of HF can be removed by performing two additional microwave cycles after sample dissolution. HF migrates from the digestion solution to a scavenger (ultrapure H2O) via a simple physical mechanism, and then, it can be safely dismissed/recycled. The procedure was validated by a soil reference material (NIST 2710), and no external or cross-contamination was observed for the 27 trace elements studied. The results demonstrate the suitability of this protocol for ultra-trace analysis when the utilization of HF is mandatory

    Exploring the Adsorption of Pb on Microalgae-Derived Biochar: A Versatile Material for Environmental Remediation and Electroanalytical Applications

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    Biochar, a carbon material obtained by pyrolysis of biomasses, is increasingly applied in environmental remediation and sensing thanks to its functional properties, cost-effectiveness and eco-friendliness. The adsorption capacity of biochar, strictly dependent on its specific surface area, heteroatom doping and surface functional groups, is crucial for these applications. Here, biochar produced at low temperature (350◦ C) from a marine microalga (Nannochloropsis sp.) is proposed as an efficient adsorbent of lead (II) ions in aqueous solution; this production strategy promotes the natural self-doping of biochar without requiring harsh conditions. The kinetics and thermodynamics of the adsorption process, as well as the effect of pH, ionic strength and dissolved organic matter on the adsorption efficiency were systematically assessed. The microalgae-derived biochar shows superior adsorption performances compared to a nutshell-derived one (used as a reference of lignocellulosic feedstocks) under all the tested conditions. The microalgae-derived biochar was finally used to decorate screen-printed carbon electrodes to improve the electroanalytical performances towards the voltammetric detection of lead (II) ions. A two-fold increase in sensitivity was obtained compared to the unmodified electrode thanks to the enhanced electron transfer and adsorption properties provided by biochar. These results highlight the potentialities of microalgae-derived biochar for environmental and sensing applications

    Scintillation efficiency of liquid xenon for nuclear recoils with the energy down to 5 keV

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    The scintillation efficiency of liquid xenon for nuclear recoils has been measured to be nearly constant in the recoil energy range from 140 keV down to 5 keV. The average ratio of the efficiency for recoils to that for gamma-rays is found to be 0.19+-0.02.Comment: 13 pages, 5 figure
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