Search results for "wax"
showing 10 items of 107 documents
Active hiding of social information from information-parasites
2014
Background: Coevolution between pairs of different kind of entities, such as providers and users of information, involves reciprocal selection pressures between them as a consequence of their ecological interaction. Pied flycatchers ( Ficedula hypoleuca ) have been shown to derive fitness benefits (larger clutches) when nesting in proximity to great tits ( Parus major ), presumably because they this way discover and obtain information about nesting sites. Tits suffer from the resulting association (smaller clutches). An arms race between the tits (information host) and the flycatchers (information parasite) could thus result . Great tits often cover eggs with nesting material before, but no…
Pesticide residues in honey bees, pollen and beeswax: Assessing beehive exposure
2018
In order to study the distribution of pesticide residues in beekeeping matrices, samples of live in-hive worker honey bees (Apis mellifera), fresh stored pollen and beeswax were collected during 2016–2017 from 45 apiaries located in different landscape contexts in Spain. A total of 133 samples were screened for 63 pesticides or their degradation products to estimate the pesticide exposure to honey bee health through the calculation of the hazard quotient (HQ). The influence of the surrounding environment on the content of pesticides in pollen was assessed by comparing the concentrations of pesticide residues found in apiaries from intensive farming landscapes to those found in apiaries loca…
Synthesis and biofilm formation reduction of pyrazole-4-carboxamide derivatives in some Staphylococcus aureus strains
2016
The ability of several N-phenyl-1H-pyrazole-4-carboxamide derivatives and other pyrazoles opportunely modified at the positions 3, 4 and 5, to reduce the formation of the biofilm in some Staphylococcus aureus strains (ATCC 29213, ATCC 25923 and ATCC 6538) were investigated. All the tested compounds were able, although to a different extent, to reduce the biofilm formation of the three bacterial strains considered. Among these, the 1-(2,5-dichlorophenyl)-5-methyl-N-phenyl-1H-pyrazole-4-carboxamide 14 resulted as the best inhibitor of biofilm formation showing an IC50 ranging from 2.3 to 32 μM, against all the three strains of S. aureus. Compound 14 also shows a good protective effect in vivo…
Polyethylene bio-degradation by caterpillars?
2017
In their recent paper on the degradation of polyethylene by caterpillars of the wax moth Galleria melonella, Bombelli et al.[1] report various experiments, including microscopic and spectroscopic data which the authors believe support the chemical digestion of the polymers by these insects. While the biodegradation of mostly inert artificial polymers is definitely a very interesting research field, we must respectfully disagree with the methodology and conclusions from this paper.
Intestinal microbiota mediates the beneficial effects of n-3 polyunsaturated fatty acids during dietary obesity,
2021
Obesity, now considered as a real worldwide epidemic affecting more than 650 million people, is complex and mainly associated with excessive energy intake and changes in eating habits favoring the consumption of diets rich in saturated fat and sugar. This multifactorial pathology is linked to chronic low grade systemic inflammation. Indeed, a high fat diet (HFD) leads to intestinal microbiota dysbiosis increasing gut permeability (partly attributed to a downregulation of genes encoding tight junction proteins) leading to an increase in bacterial lipopolysaccharides (LPS) levels so-called metabolic endotoxemia. Studies have shown that n-3 polyunsaturated fatty acids (PUFAs) are involved in t…
« Nez et langues électroniques » : bilan et perspectives pour les huiles alimentaires
2003
Le « Nez electronique », et plus recemment la « Langue electronique » ont ete fort mediatises durant la derniere decennie. Aussi est-il necessaire, avec le recul, de faire le point sur les benefices que ces technologies peuvent apporter dans le domaine des produits alimentaires, et en particulier pour huiles vegetales. On trouve une litterature relativement abondante dans ce domaine, mais les applications qui ont reussi a franchir le cap de l’utilisation industrielle sont extremement restreintes. S’agit-il d’une frilosite des industriels pour des investissements de controle-qualite ou d’un manque de fiabilite des resultats de laboratoire ? Pourtant, la demande en outils rapides de controle-…
The implication of omega-3 polyunsaturated fatty acids in retinal physiology
2007
International audience; Neuronal tissues such as the retina and the brain are characterized by their high content in phospholipids. In the retina, phospholipids can account for until 80% of total lipids and are mainly composed by species belonging to phosphatidyl-choline and phosphatidyl-ethanolamine sub-classes. Within fatty acids esterified on retinal phospholipids, omega-3 PUFAs are major components since docosahexaenoic acid (DHA) can represent until 50% of total fatty acids in the photoreceptor outer segments.For long time, DHA is known to play a major role in membrane function and subsequently in visual processes by affecting permeability, fluidity, thickness and the activation of mem…
Synthesis and influence of fatty acid esters on the foliar penetration of herbicides
1998
Abstract Synthesis of mono-esters of tetraethylene glycol and di-esters of tetraethylene glycol was accomplished from fatty acids and tetraethylene glycol in the absence of solvent and catalyst. Esterification was studied in a batch reactor by using a response surface methodology to evaluate the influence of synthesis variables such as molar substrate ratio of fatty acid relative to tetraethylene glycol (1.39–7.52), temperature (145–167°C), reaction time (0.5–8 h) on the yield of mono- and di-esters of tetraethylene glycol. A multipurpose reactor was developed for the transformation of fatty acids into pure α-monoglycerides. The 1-monoglycerides of heptanoic, undecelenic, oleic, linoleic an…
Accuracy of check-bite registration and centric condylar position
2002
In a dentate subject a jaw relation can either be determined in maximum intercuspation and is as such given by the occlusal morphology, or the mandibular position can be allocated according to the centric position of the condyles. For comprehensive restorative treatment or analytic measures of the occlusion it is important to record the centric condylar position. Various registration methods have been described in the literature, but there is no consensus on which is the 'best'. The aim of the present study was therefore to assess the accuracy of various registration methods and evaluate a possible influence of the used materials. Four dentists were involved in the clinical part of the stud…
Surface charge fine tuning of reversed-phase/weak anion-exchange type mixed-mode stationary phases for milder elution conditions.
2015
A series of new mixed-mode reversed-phase/weak anion-exchange (RP/WAX) phases have been synthesized by immobilization of N-undecenyl-3-α-aminotropane onto thiol-modified silica gel by thiol-ene click chemistry and subsequent introduction of acidic thiol-endcapping functionalities of different type and surface densities. Click chemistry allowed to adjust a controlled surface concentration of the RP/WAX ligand in such a way that a sufficient quantity of residual thiols remained unmodified which have been capped by thiol click with either 3-butenoic acid or allylsulfonic acid as co-ligands. In another embodiment, performic acid oxidation of N-undecenyl-3-α-aminotropane-derivatized thiol-modifi…