Polyglycerol as a water-soluble and biocompatible hyperbranched polymer was covalently grafted on... more Polyglycerol as a water-soluble and biocompatible hyperbranched polymer was covalently grafted on the surface of superparamagnetic iron oxide nanoparticles. With this aim, superparamagnetic magnetite nanoparticles were prepared by coprecipitation in aqueous media, then the surface of nanoparticles was modified to introduce the reactive groups on the surface of nanoparticles. After that, polyglycerol was grafted on the surface of nanoparticles by ring-opening anionic polymerization of glycidol using n-bulyllithium as initiator. The magnetometry, relaxometry and phantom MRI experiments of this highly stable ferrofluid showed its high potential as a negative MRI contrast agent. Calculated r 1 and r 2 relaxivities at different magnetic fields were higher than the values reported for commercially available iron oxide contrast agents. The in vivo MRI studies showed that, after intravenous injection into mice, the particles produced a strong negative contrast in liver and kidneys, which persisted for 80 min (in liver) to 110 min (in kidneys). The negative contrast of the liver and kidneys weakened over the time, suggesting that polyglycerol coating renders the nanoparticles stealth and possibly optimal for renal excretion.
To study in vitro the proton relaxation induced in tissues by ferritin, the iron-storing protein ... more To study in vitro the proton relaxation induced in tissues by ferritin, the iron-storing protein of mammals.
Agamid lizards use tongue prehension for capturing all types of prey. The purpose of this study w... more Agamid lizards use tongue prehension for capturing all types of prey. The purpose of this study was to investigate the functional relationship between tongue structure, both surface and musculature, and function during prey capture in Pogona vitticeps. The lack of a detailed description of the distribution of fibre-types in the tongue muscles in some iguanian lizards has hindered the understanding of the functional morphology of the lizard tongue. Three methodological approaches were used to fill this gap. First, morphological analyses were performed (i) on the tongue surface through scanning electron microscopy, and (ii) on the lingual muscle by histological coloration and histochemistry to identify fibre-typing. Secondly, kinematics of prey capture was quantified by using high-speed video recordings to determine the movement capabilities of the tongue. Finally, electromyography (EMG) was used to identify the motor pattern tongue muscles during prey capture. Morphological and functional data were combined to discuss the functional morphology of the tongue in agamid lizards, in relation to their diet. During tongue protraction, M. genioglossus contracts 420 ± 96 ms before tongue-prey contact. Subsequently, Mm. verticalis and hyoglossus contract throughout tongue protraction and retraction. Significant differences are found between the timing of activity of the protractor muscles between omnivorous agamids (Pogona sp., this study) and insectivorous species (Agama sp.), despite similar tongue and jaw kinematics. The data confirm that specialisation toward a diet which includes more vegetal materials is associated with significant changes in tongue morphology and function. Histoenzymology demonstrates that protractor and retractor muscles differ in fibre composition. The proportion of fast glycolytic fibres is significantly higher in the M. hyoglossus (retractor muscle) than in the M. genioglossus (protractor muscle), and this difference is proposed to be associated with differences in the velocity of tongue protrusion and retraction (5 ± 5 and 40 ± 13 cm s(-1) , respectively), similar to Chamaeleonidae. This study provides a way to compare fibre-types and composition in all iguanian and scleroglossan lizards that use tongue prehension to catch prey.
Polyglycerol as a water-soluble and biocompatible hyperbranched polymer was covalently grafted on... more Polyglycerol as a water-soluble and biocompatible hyperbranched polymer was covalently grafted on the surface of superparamagnetic iron oxide nanoparticles. With this aim, superparamagnetic magnetite nanoparticles were prepared by coprecipitation in aqueous media, then the surface of nanoparticles was modified to introduce the reactive groups on the surface of nanoparticles. After that, polyglycerol was grafted on the surface of nanoparticles by ring-opening anionic polymerization of glycidol using n-bulyllithium as initiator. The magnetometry, relaxometry and phantom MRI experiments of this highly stable ferrofluid showed its high potential as a negative MRI contrast agent. Calculated r 1 and r 2 relaxivities at different magnetic fields were higher than the values reported for commercially available iron oxide contrast agents. The in vivo MRI studies showed that, after intravenous injection into mice, the particles produced a strong negative contrast in liver and kidneys, which persisted for 80 min (in liver) to 110 min (in kidneys). The negative contrast of the liver and kidneys weakened over the time, suggesting that polyglycerol coating renders the nanoparticles stealth and possibly optimal for renal excretion.
To study in vitro the proton relaxation induced in tissues by ferritin, the iron-storing protein ... more To study in vitro the proton relaxation induced in tissues by ferritin, the iron-storing protein of mammals.
Agamid lizards use tongue prehension for capturing all types of prey. The purpose of this study w... more Agamid lizards use tongue prehension for capturing all types of prey. The purpose of this study was to investigate the functional relationship between tongue structure, both surface and musculature, and function during prey capture in Pogona vitticeps. The lack of a detailed description of the distribution of fibre-types in the tongue muscles in some iguanian lizards has hindered the understanding of the functional morphology of the lizard tongue. Three methodological approaches were used to fill this gap. First, morphological analyses were performed (i) on the tongue surface through scanning electron microscopy, and (ii) on the lingual muscle by histological coloration and histochemistry to identify fibre-typing. Secondly, kinematics of prey capture was quantified by using high-speed video recordings to determine the movement capabilities of the tongue. Finally, electromyography (EMG) was used to identify the motor pattern tongue muscles during prey capture. Morphological and functional data were combined to discuss the functional morphology of the tongue in agamid lizards, in relation to their diet. During tongue protraction, M. genioglossus contracts 420 ± 96 ms before tongue-prey contact. Subsequently, Mm. verticalis and hyoglossus contract throughout tongue protraction and retraction. Significant differences are found between the timing of activity of the protractor muscles between omnivorous agamids (Pogona sp., this study) and insectivorous species (Agama sp.), despite similar tongue and jaw kinematics. The data confirm that specialisation toward a diet which includes more vegetal materials is associated with significant changes in tongue morphology and function. Histoenzymology demonstrates that protractor and retractor muscles differ in fibre composition. The proportion of fast glycolytic fibres is significantly higher in the M. hyoglossus (retractor muscle) than in the M. genioglossus (protractor muscle), and this difference is proposed to be associated with differences in the velocity of tongue protrusion and retraction (5 ± 5 and 40 ± 13 cm s(-1) , respectively), similar to Chamaeleonidae. This study provides a way to compare fibre-types and composition in all iguanian and scleroglossan lizards that use tongue prehension to catch prey.
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