315 research outputs found
Identification of onosma visianii roots extract and purified shikonin derivatives as potential acaricidal agents against tetranychus urticae
There is an increasing need for the discovery of reliable and eco-friendly pesticides and natural plant-derived products may play a crucial role as source of new active compounds. In this research, a lipophilic extract of Onosma visianii roots extract containing 12% of shikonin derivatives demonstrated significant toxicity and inhibition of oviposition against Tetranychus urticae mites. Extensive chromatographic separation allowed the isolation of 11 naphthoquinone derivatives that were identified by spectral techniques and were tested against Tetranychus urticae. All the isolated compounds presented effects against the considered mite and isobutylshikonin (1) and isovalerylshikonin (2) were the most active, being valuable model compounds for the study of new anti-mite agents
Chemical composition of Cinnamosma madagascariensis (Cannelaceae) essential oil and its larvicidal potential against the filariasis vector Culex quinquefasciatus Say
Madagascar flora is diverse and unique. Cinnamosma madagascariensis is an endemic species widely present in
the forests of Madagascar. This plant has important traditional uses ranging from management of dementia, epilepsy, headache to malaria. Fewdata have been reported about the chemical composition of the essential oil, and no studies have been published on its bioactivity againstmosquitoes. Here,we focus on the chemical composition of essential oils extracted from C. madagascariensis stem bark and leaves, and their larvicidal potential against the filariasis vector Culex quinquefasciatus. GC-MS analysis revealed differences between the chemical volatile profiles of leaves and bark oils. In the former, linalool (30.1%), limonene (12.0%), myrcene (8.9%) and α-pinene (8.4%) were the major constituents, while in the latter β-pinene (33.3%), α-pinene (19.3%) and limonene (12.0%) were the most representative compounds. Acute toxicity experiments conducted on larvae of the filariasis vector C. quinquefasciatus led to LC50 of 61.6 μL L−1 and 80.1 μL L−1 for the bark and the leaf essential oils, respectively. Overall, the chance to use compounds from the C. madagascariensis bark and leaf essential oils against filariasis vectors seems promising, since they are effective at moderate doses and could be an advantageous alternative to build newer and safer mosquito control tools. To the best of our knowledge, this is the first report about the chemical composition of C. madagascariensis essential oils
Insecticidal Activity of Four Essential Oils Extracted from Chilean Patagonian Plants as Potential Organic Pesticide
Patagonia is a geographical area characterized by a wide plant biodiversity. Several native plant species are traditionally used in medicine by the local population and demonstrated to be sources of biologically active compounds. Due to the massive need for green and sustainable pesticides, this study was conducted to evaluate the insecticidal activity of essential oils (EOs) from understudied plants growing in this propitious area. Ciprés (Pilgerodendron uviferum), tepa (Laureliopsis philippiana), canelo (Drimys winteri), and paramela (Adesmia boronioides) EOs were extracted through steam distillation, and their compositions were analyzed through GC–MS analysis. EO contact toxicity against Musca domestica L., Spodoptera littoralis (Boisd.), and Culex quinquefasciatus Say was then evaluated. As a general trend, EOs performed better on housefly males over females. Ciprés EO showed the highest insecticidal efficacy. The LD50(90) values were 68.6 (183.7) and 11.3 (75.1) µg adult−1 on housefly females and males, respectively. All EOs were effective against S. littoralis larvae; LD50 values were 33.2–66.7 µg larva−1, and tepa EO was the most effective in terms of LD90 (i.e., <100 µg larva−1). Canelo, tepa, and paramela EOs were highly effective on C. quinquefasciatus larvae, with LC50 values < 100 µL L−1. Again, tepa EO achieved LD90 < 100 µL L−1. This EO was characterized by safrole (43.1%), linalool (27.9%), and methyl eugenol (6.9%) as major constituents. Overall, Patagonian native plant EOs can represent a valid resource for local stakeholders, to develop effective insecticides for pest and vector management, pending a proper focus on their formulation and nontarget effects
Chemical composition and broad-spectrum insecticidal activity of the flower essential oil from an ancient Sicilian food plant, Ridolfia segetum
Several species of the family Apiaceae are aromatic herbs that produce essential oils usable on an industrial scale for pharmaceutical, cosmetical and food purposes. Particularly, some essential oils, as green insecticides, may replace synthetic insecticides keeping most of their efficacy and avoiding environmental pollution or human’ poisoning. In the present study, we explored the in-secticidal potential of Ridolfia segetum (L.) Moris essential oil (EO), rich in α-phellandrene (49.3%), β-phellandrene (9.2%), terpinolene (20.7%) and piperitenone oxide (5.9%), against three different pests, Culex quinquefasciatus, Musca domestica and Spodoptera littoralis. For this purpose, the flower EO was obtained by hydrodistillation and its composition was achieved by gas chromatography/mass spectrometry (GC/MS). Concerning mosquitocidal efficacy, the EO showed a noteworthy toxicity against C. quinquefasciatus 3rd instar larvae, with a LC50=27.1 µL L-1 and LC90=42.5 µL L-1. Regarding M. domestica, a different toxicity of the R. segetum EO was found on male and female flies, calculating LD50 values of 10.5 and 50.8 µg adult-1, respectively. The EO was also toxic to S. littoralis 3rd instar larvae, achieving LD50 and LD90 values of 37.9 and 99.6 µg larva-1, respectively. Overall, this flower EO extracted from a traditional Sicilian food plant merits further investigation for the development of green insecticide formulations to be used in the real-world conditions, pending a careful assessment of non-target toxicity on beneficial organisms
Developing a highly stable Carlina acaulis essential oil nanoemulsion for managing Lobesia botrana
The growing interest in the development of green pest management strategies is leading to the exploitation of essential oils (EOs) as promising botanical pesticides. In this respect, nanotechnology could efficiently support the use of EOs through their encapsulation into stable nanoformulations, such as nanoemulsions (NEs), to improve their stability and efficacy. This technology assures the improvement of the chemical stability, hydrophilicity, and environmental persistence of EOs, giving an added value for the fabrication of natural insecticides effective against a wide spectrum of insect vectors and pests of public and agronomical importance. Carlina acaulis (Asteraceae) root EO has been recently proposed as a promising ingredient of a new generation of botanical insecticides. In the present study, a highly stable C. acaulis-based NE was developed. Interestingly, such a nanosystem was able to encapsulate 6% (w/w) of C. acaulis EO, showing a mean diameter of around 140 nm and a SOR (surfactant-to-oil ratio) of 0.6. Its stability was evaluated in a storage period of six months and corroborated by an accelerated stability study. Therefore, the C. acaulis EO and C. acaulis-based NE were evaluated for their toxicity against 1st instar larvae of the European grapevine moth (EGVM), Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae), a major vineyard pest. The chemical composition of C. acaulis EO was investigated by gas chromatography–mass spectrometry (GC–MS) revealing carlina oxide, a polyacetylene, as the main constituent. In toxicity assays, both the C. acaulis EO and the C. acaulis-based NE were highly toxic to L. botrana larvae, with LC50 values of 7.299 and 9.044 µL/mL for C. acaulis EO and NE, respectively. The C. acaulis-based NE represents a promising option to develop highly stable botanical insecticides for pest management. To date, this study represents the first evidence about the insecticidal toxicity of EOs and EO-based NEs against this major grapevine pest
Developing a highly stable carlina acaulis essential oil nanoemulsion for managing Lobesia Botrana
The growing interest in the development of green pest management strategies is leading to the exploitation of essential oils (EOs) as promising botanical pesticides. In this respect, nanotechnology could efficiently support the use of EOs through their encapsulation into stable nanoformulations, such as nanoemulsions (NEs), to improve their stability and efficacy. This technology assures the improvement of the chemical stability, hydrophilicity, and environmental persistence of EOs, giving an added value for the fabrication of natural insecticides effective against a wide spectrum of insect vectors and pests of public and agronomical importance. Carlina acaulis (Asteraceae) root EO has been recently proposed as a promising ingredient of a new generation of botanical insecticides. In the present study, a highly stable C. acaulis-based NE was developed. Interestingly, such a nanosystem was able to encapsulate 6% (w/w) of C. acaulis EO, showing a mean diameter of around 140 nm and a SOR (surfactant-to-oil ratio) of 0.6. Its stability was evaluated in a storage period of six months and corroborated by an accelerated stability study. Therefore, the C. acaulis EO and C. acaulis-based NE were evaluated for their toxicity against 1st instar larvae of the European grapevine moth (EGVM), Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae), a major vineyard pest. The chemical composition of C. acaulis EO was investigated by gas chromatography–mass spectrometry (GC–MS) revealing carlina oxide, a polyacetylene, as the main constituent. In toxicity assays, both the C. acaulis EO and the C. acaulis-based NE were highly toxic to L. botrana larvae, with LC50 values of 7.299 and 9.044 µL/mL for C. acaulis EO and NE, respectively. The C. acaulis-based NE represents a promising option to develop highly stable botanical insecticides for pest management. To date, this study represents the first evidence about the insecticidal toxicity of EOs and EO-based NEs against this major grapevine pest
A Proposed Process for Managing the First Amendment Aspects of Campus Hate Speech
For public institutions, attempts to regulate hate speech raise substantial legal issues under the First Amendment of the U.S. Constitution. For private institutions, which may not be bound by the First Amendment, attempts to regulate hate speech raise sensitive policy questions concerning the role of free expression on campus. Numerous articles (many of which are listed in the references below) have undertaken substantive analysis of these constitutional issues and policy questions. In contrast, this article explores a preliminary and overarching concern: the process by which a college or university addresses the problem of hate speech, and in particular the process by which the institution manages the First Amendment aspects of the problem. In other words, this article focuses on the decision-making process rather than on the decisions themselves; it is the journey, not the destination, that is of primary concern
Liquidation of Corporation
Import 22/07/2015Diplomová práce se zabývá procesem likvidace obchodních společností v České republice. Cílem této práce je popsat postup likvidace obchodních společností a upozornit na některé problémy, které proces likvidace s sebou přináší, poukázat na řešení základních organizačních a ekonomických otázek související s likvidací a propojit právní a daňový pohled na likvidaci. Práce je rozdělena do čtyř kapitol. V první kapitole jsou definovány jednotlivé právní formy obchodních společností a možné způsoby jejich zrušení. Druhá kapitola se zabývá popisem likvidačního procesu, kdy jsou popsány jednotlivé kroky likvidátora v průběhu likvidace. Třetí kapitola je věnována osobě likvidátora, podmínky nutné k výkonu likvidátora, povolání likvidátora do funkce. Čtvrtá kapitola je věnována praktickým problémům spojenými s procesem likvidace.Thesis deals with the process of liquidation of corporations in the Czech Republic. The aim of this thesis is to describe the procedure of liquidation and to point out some possible problems that could occur during liquidation. The legal and tax point view of the topic will also be included.
Thesis is divided into 4 main chapters. Different legal forms of the corporations and the ways of dissolution of companies are defined in the first chapter. The second chapter pursues the process of liquidation. One part of this chapter is devoted to activities of the liquidator. The person of the liquidator, including his competences and required skills, is described in the third chapter. The last chapter is focused on practical problems concerning the process of liquidation.119 - Katedra právavelmi dobř
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Ocimum basilicum essential oil combined with deltamethrin to improve the management of Spodoptera frugiperda
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