399 research outputs found
Magnetoliposomes: Envisioning new strategies for water decontamination
No full textIn this work, the inclusion of magnetic nanoparticles (MNPs) within phospholipid vesicles has been investigated as novel strategy for improving stability and reactivity of these nanoparticles and extending their potential use in the environmental field. Two phospholipids able to form liposomes characterized by different rigidity and stiffness, were used as potential carriers of MNPs. The magneto-responsive liposomes were investigated for their physicochemical and stability properties. In particular, the stability of the two systems was indirectly investigated evaluating the ability of the hybrid constructs to retain a fluorescent marker in their structure. Alterations in the permeability of the membranes were determined by the rate of the marker release from the liposomes, under both mechanical and thermal stress conditions. Copyright © 2016, AIDIC Servizi S.r.l
Controlled release from magnetoliposomes aqueous suspensions exposed to a low intensity magnetic field
No full textRecently, the use of liposomes loaded with magnetic nanoparticles (magnetoliposomes, (MLs)) has been intensely growing as a new drug delivery system. With the use of alternating magnetic fields, it is possible to remotely control the delivery of a drug or any other macromolecule loaded inside the MLs. In this experiment, the release of a fluorescent dye from MLs is achieved through an alternating magnetic field of 20kHz and amplitude below 100A/m, and without a macroscopic temperature increase. Bioelectromagnetics. 35:309-312, 2014. © 2014 Wiley Periodicals, Inc
Controllable release from high-transition temperature magnetoliposomes by low-level magnetic stimulation
No full textHigh-transition temperature liposomes with embedded coated magnetite nanoparticles were prepared using the thin lipid film hydration method in order to obtain magnetoliposomes not sensitive to temperature increase (at least up to 50. °C). Accordingly, drug can be released from such magnetoliposomes using a low-level electromagnetic field as triggering agent, while no delivery would be obtained with temperature increase within the physiological acceptable range. The hypothesized release mechanism involves mechanical stress of the liposome membrane due to nanoparticles oscillations and it is investigated by means of a numerical model evaluated using multiphysics simulations. The carrier content was repetitively released by switching on and off a 20. kHz, 60. A/m magnetic field. The results indicated high reproducibility of cycle-to-cycle release induced by the magnetic-impelled motions driving to the destabilization of the bilayer rather than the liposome phase transition or the destruction of the liposome structure. © 2015 Published by Elsevier B.V
A wide-band bio-chip for real-time optical detection of bioelectromagnetic interactions with cells
No full textThe analytical and numerical design, implementation, and experimental validation of a new grounded closed coplanar waveguide for wide-band electromagnetic exposures of cells and their optical detection in real-time is reported. The realized device fulfills high-quality requirements for novel bioelectromagnetic experiments, involving elevated temporal and spatial resolutions. Excellent performances in terms of matching bandwidth (less than -10 dB up to at least 3 GHz), emission (below 1 × 10-6 W/m2) and efficiency (around 1) have been obtained as revealed by both numerical simulations and experimental measurements. A low spatial electric field inhomogeneity (coefficient of variation of around 10 %) has been achieved within the cell solutions filling the polydimethylsiloxane reservoir of the conceived device. This original bio-chip based on the grounded closed coplanar waveguide concept opens new possibilities for the development of controlled experiments combining electromagnetic exposures and sophisticated imaging using optical spectroscopic techniques. © 2018 The Author(s)
High-intensity static magnetic field exposure devices for in vitro experiments on biopharmaceutical plant factories in aerospace environments
No full textThree high-intensity static magnetic field (SMF) exposure devices have been designed and realized for application to in vitro experimental research on hairy root cultures, supposed to grow in extreme environments- as those of space aircrafts- for producing biopharmaceutical molecules. The devices allow the exposure at two different levels of induction magnetic (B) field (250 mT and 500 mT) plus sham for blind exposure. The exposure levels can be considered representative of possible B-fields experienced within the habitat of a spacecraft in presence of active magnetic shielding systems. Each device can house a single 85-mm diameter Petri dish. Numerical simulations have been performed to accurately evaluate the B-field distribution in the biological target. Numerical results have been confirmed by measured data, proving that designed setups allows exposure to SMFs with a homogeneity better than 90%. The exposure devices will be employed for experiments scheduled within BIOxTREME research project, funded by the Italian Space Agency (ASI). © 2015 IEEE
Microwave exposure systems for in vivo biological experiments: A systematic review
No full textThis paper provides a systematic review and classification of in vivo microwave exposure systems used from 1999 for bioelectromagnetic investigations. The main features of each system's typology are presented and discussed for different types of experiments. From our critical analysis, some key issues have been identified and addressed concerning the importance of reliable dosimetric characterization of exposure systems for different types of in vivo study. Our review of the strengths and weaknesses of each electromagnetic exposure system will be useful for identifying those features necessary for new bioelectromagnetics studies involving exposures to high-frequency fields, typical of those used in new telecommunication technologies, and multiple sources. © 1963-2012 IEEE
Please Don't! The Automatic Extrapolation of Dangerous Intentions
Get PDFFacial emotions and emotional body postures can easily grab attention in social communication. In the context of faces, gaze has been shown as an important cue for orienting attention, but less is known for other important body parts such as hands. In the present study we investigated whether hands may orient attention due to the emotional features they convey. By implying motion in static photographs of hands, we aimed at furnishing observers with information about the intention to act and at testing if this interacted with the hand automatic coding. In this study, we compared neutral and frontal hands to emotionally threatening hands, rotated along their radial-ulnar axes in a Sidedness task (a Simon-like task based on automatic access to body representation). Results showed a Sidedness effect for both the palm and the back views with either neutral and emotional hands. More important, no difference was found between the two views for neutral hands, but it emerged in the case of the emotional hands: faster reaction times were found for the palm than the back view. The difference was ascribed to palm views’ “offensive” pose: a source of threat that might have raised participants' arousal. This hypothesis was also supported by conscious evaluations of the dimensions of valence (pleasant-unpleasant) and arousal. Results are discussed in light of emotional feature coding
Complex magnetic field exposure system for in vitro experiments at intermediate frequencies
No full textIn occupational environments, an increasing number of electromagnetic sources emitting complex magnetic field waveforms in the range of intermediate frequencies is present, requiring an accurate exposure risk assessment with both in vitro and in vivo experiments. In this article, an in vitro exposure system able to generate complex magnetic flux density B-fields, reproducing signals from actual intermediate frequency sources such as magnetic resonance imaging (MRI) scanners, for instance, is developed and validated. The system consists of a magnetic field generation system and an exposure apparatus realized with a couple of square coils. A wide homogeneity (99.9%) volume of 210×210×110mm3 was obtained within the coils, with the possibility of simultaneous exposure of a large number of standard Petri dishes. The system is able to process any numerical input sequence through a filtering technique aimed at compensating the coils' impedance effect. The B-field, measured in proximity to a 1.5T MRI bore during a typical examination, was excellently reproduced (cross-correlation index of 0.99). Thus, it confirms the ability of the proposed setup to accurately simulate complex waveforms in the intermediate frequency band. Suitable field levels were also attained. Moreover, a dosimetry index based on the weighted-peak method was evaluated considering the induced E-field on a Petri dish exposed to the reproduced complex B-field. The weighted-peak index was equal to 0.028 for the induced E-field, indicating an exposure level compliant with the basic restrictions of the International Commission on Non-Ionizing Radiation Protection. © 2012 Wiley Periodicals, Inc
Appropriateness of urea breath test: A prospective observational study based on Maastricht 2000 guidelines
No full textBackground: the urea breath test is routinely used for diagnosing or confirming the eradication of Helicobacter pylori.Aim: to evaluate the appropriateness of urea breath test referrals.Methods: the age, sex, symptoms, endoscopic findings, use of non-steroidal anti-inflammatory drugs, family history of gastric cancer or H. pylori infection and concomitant diseases of patients referred for urea breath testing in a 1-year period were recorded. The appropriateness of urea breath test referrals was judged according to Maastricht guidelines.Results: one thousand, three hundred and twenty subjects (47 +/- 16 years) were referred in 2001: 578 (43.8%) for the diagnosis and 742 (56.2%) for confirmation of the eradication of H. pylori. The urea breath test was considered to be appropriate in 836 (63.3%) patients, inappropriate in 192 (14.5%) and appropriate but avoidable in 292 (22.1%). The appropriateness ratios of urea breath test referrals were 4.6 and 9.0 (P < 0.0001) for general practitioners and gastroenterologists, respectively. Of the patients (n = 230) with uninvestigated dyspepsia, who underwent urea breath testing according to a 'test and treat' strategy, 98 (42.6%) presented at least one risk factor for organic disease.Conclusions: in Italy, nearly 36% of urea breath test referrals are inappropriate or could be avoided if all dyspeptic patients with risk factors were referred for endoscopy or all dyspeptic patients undergoing endoscopy were tested for H. pylori infection with biopsy methods. Both general practitioners and, to a lesser extent, gastroenterologists require educational programmes to deal effectively with H. pylori
Controlled release from magnetoliposomes aqueous suspensions exposed to a low intensity magnetic field
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