General relativity (GR) represents the most recent theory of gravity, on which all modern astrophysics is based, including some of the most astonishing results of physics research. Nevertheless, its ...study is limited to university courses, while being ignored at high-school level. To introduce GR in high school, one of the approaches that can be used is the so-called rubber sheet analogy (RSA), i.e. comparing space-time to a rubber sheet that deforms under a weight. In this paper, we analyse the efficacy of an activity for high-school students held at the Department of Mathematics and Physics of Roma Tre University that adopts the RSA to address several topics related to gravity. We present the results of the questionnaires we administered to over 150 Italian high-school students to investigate their understanding of the topics treated.
The human intestinal Caco-2 cell line has been extensively used over the last twenty years as a model of the intestinal barrier. The parental cell line, originally obtained from a human colon ...adenocarcinoma, undergoes in culture a process of spontaneous differentiation that leads to the formation of a monolayer of cells, expressing several morphological and functional characteristics of the mature enterocyte. Culture-related conditions were shown to influence the expression of these characteristics, in part due to the intrinsic heterogeneity of the parental cell line, leading to selection of sub-populations of cells becoming prominent in the culture. In addition, several clonal cell lines have been isolated from the parental line, exhibiting in general a more homogeneous expression of differentiation traits, while not always expressing all characteristics of the parental line. Culture-related conditions, as well as the different Caco-2 cell lines utilized in different laboratories, often make it extremely difficult to compare results in the literature. This review is aimed at summarizing recent, or previously unreviewed, data from the literature on the effects of culture-related factors and the influence of line sub-types (parental vs. different clonal lines) on the expression of differentiation traits important for the use of Caco-2 cells as a model of the absorptive and defensive properties of the intestinal mucosa. Since the use of Caco-2 cells has grown exponentially in recent years, it is particularly important to highlight these methodological aspects in order to promote the standardization and optimisation of this intestinal model.
Abstract
We developed and validated a protocol based on Single Particle Inductively Coupled Plasma Mass Spectrometry (SP ICP-MS) to detect composition and size of metal nanoparticles (MNPs) in tattoo ...inks end
ex vivo
tattooed human skin explants. The explants were tattooed with different inks using an ordinary tattoo machine. Then, 72 hours after tattooing, skin explants were subjected to alkaline extraction by tetramethylammonium hydroxide solution and MNPs of Ag, Al
2
O
3
, Au, Cr
2
O
3
, CuO, Fe
2
O
3
, TiO
2
and ZnO were analysed for particle composition and size by SP ICP-MS. The method was validated by assessing the limit of detection, accuracy, precision, and size stability over 72 hours. Particles of Al
2
O
3
, Cr
2
O
3
, CuO, Fe
2
O
3
, TiO
2
and ZnO were observed in human skin in the range from 27 nm to 153 nm, and from 26 nm to 228 nm in tattoo inks. Ag and Au NPs were not found neither in inks nor in the skin. Advantages of the protocol were the ability to simultaneously detect the composition of particles and their size, the straightforward sample preparation, the high sensitivity and precision, and the speed of execution of the analysis. The developed methodology can be applied to skin exposed to other consumer products topically applied, such as sunscreens, cosmetics, personal care products and medical devices, which can be all sources of MNPs, in order to improve knowledge and support the human exposure assessment process.
Abstract
The main source of systematic uncertainty on neutrino cross section measurements at the GeV scale originates from the poor knowledge of the initial flux. The reduction of this uncertainty to ...1% can be achieved through the monitoring of charged leptons produced in association with neutrinos. The goal of the ENUBET ERC project is to prove the feasibility of such a monitored neutrino beam. In this contribution, the final results of the ERC project, together with the complete assessment of the feasibility of its concept, are presented. An overview of the detector technology for a next generation of high precision neutrino-nucleus cross section measurements, to be performed with the ENUBET neutrino beam, is also given.
The quality of reconstructed dynamic PET images, as well as the statistical reliability of the estimated pharmacokinetic parameters is often compromised by high levels of statistical noise, ...particularly at the voxel level. Many denoising strategies have been proposed, both in the temporal and spatial domain, which substantially improve the signal to noise ratio of the reconstructed dynamic images. However, although most filtering approaches are fairly successful in reducing the spatio-temporal inter-voxel variability, they may also average out or completely eradicate the critically important temporal signature of a transient neurotransmitter activation response that may be present in a non-steady state dynamic PET study. In this work, we explore an approach towards temporal denoising of non-steady state dynamic PET images using an artificial neural network, which was trained to identify the temporal profile of a time-activity curve, while preserving any potential activation response. We evaluated the performance of a feed-forward perceptron neural network to improve the signal to noise ratio of dynamic 11Craclopride activation studies and compared it with the widely used highly constrained back projection (HYPR) filter. Results on both simulated Geant4 Application for Tomographic Emission data of a realistic rat brain phantom and experimental animal data of a freely moving animal study showed that the proposed neural network can efficiently improve the noise characteristics of dynamic data in the temporal domain, while it can lead to a more reliable estimation of voxel-wise activation response in target region. In addition, improvements in signal-to-noise ratio achieved by denoising the dynamic data using the proposed neural network led to improved accuracy and precision of the estimated model parameters of the lp-ntPET model, compared to the HYPR filter. The performance of the proposed denoising approach strongly depends on the amount of noise in the dynamic PET data, with higher noise leading to substantially higher variability in the estimated parameters of the activation response. Overall, the feed-forward network led to a similar performance as the HYPR filter in terms of spatial denoising, but led to notable improvements in terms of temporal denoising, which in turn improved the estimation activation parameters.
Abstract
The ENUBET ERC project, also included in the CERN Neutrino Platform as NP06/ENUBET, is developing a new neutrino beam based on conventional techniques in which the flux and the flavor ...composition are known with unprecedented precision (
O
(1%)). Such a goal is accomplished monitoring the associated charged leptons produced in the decay region of the ENUBET facility. Positrons and muons from kaon decays are measured by a segmented calorimeter instrumenting the walls of the decay tunnel, while muon stations after the hadron dump can be used to monitor the neutrino component from pion decays. Furthermore, the narrow momentum width (<10%) of the beam provides a precise measurement (
O
(10%)) of the neutrino energy on an event by event basis, thanks to its correlation with the radial position of the interaction at the neutrino detector. ENUBET is therefore an ideal facility for a high precision neutrino cross-section measurement at the GeV scale, that could enhance the discovery potential of the next-generation of long baseline experiments. It is also a powerful tool for testing the sterile neutrino hypothesis and to investigate possible non-standard interactions.
From almost 20 years the “in vitro” model has gained a wide ground in toxicological investigation, providing advanced tools, reliable protocols, mechanistic information. These advancements have been ...done thanks to different approaches, addressed at improving chemical testing and validating procedures, at exploring the cellular and molecular basis of toxicity, at studying the modifications that xenobiotics undergo in the cellular environment. In this review the most advanced cellular models, the mechanisms of cell death, the techniques to monitor gene activation, following chemical exposure, is highlighted. Moreover the more recent in vitro models to approach the biotransformation issue will be presented.
A comprehensive understanding of how the brain responds to a changing environment requires techniques capable of recording functional outputs at the whole-brain level in response to external stimuli. ...Positron emission tomography (PET) is an exquisitely sensitive technique for imaging brain function but the need for anaesthesia to avoid motion artefacts precludes concurrent behavioural response studies. Here, we report a technique that combines motion-compensated PET with a robotically-controlled animal enclosure to enable simultaneous brain imaging and behavioural recordings in unrestrained small animals. The technique was used to measure in vivo displacement of 11Craclopride from dopamine D2 receptors (D2R) concurrently with changes in the behaviour of awake, freely moving rats following administration of unlabelled raclopride or amphetamine. The timing and magnitude of 11Craclopride displacement from D2R were reliably estimated and, in the case of amphetamine, these changes coincided with a marked increase in stereotyped behaviours and hyper-locomotion. The technique, therefore, allows simultaneous measurement of changes in brain function and behavioural responses to external stimuli in conscious unrestrained animals, giving rise to important applications in behavioural neuroscience.
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•A method for concurrent PET and behavioural response studies in freely moving rats.•11Craclopride displacement and reduced motor activity following iv raclopride.•11Craclopride displacement, hyperactivity and stereotypy following iv amphetamine.
Building Academic Literacy is a coach-in-a-pocket for educators seeking to build strong academic literacy and higher-order thinking. This book is for anyone with responsibility for instruction - ...teachers, instructional coaches, professional developers, principals, curriculum leaders, teacher preparation faculty. It provides pathways to developing higher-order thinking in every student and setting.
The central role of T regulatory cells in the responses against harmless environmental antigens has been confirmed by many studies. Impaired T regulatory cell function is implicated in many ...pathological conditions, particularly allergic diseases. The “hygiene hypothesis” suggests that infections and infestations may play a protective role for allergy, whereas environmental pollutants favor the development of allergic diseases. Developing countries suffer from a variety of infections and are also facing an increasing diffusion of environmental pollutants. In these countries allergies increase in relation to the spreading use of xenobiotics (pesticides, herbicides, pollution, etc.) with a rate similar to those of developed countries, overcoming the protective effects of infections. We review here the main mechanisms of non-self tolerance, with particular regard to relations between T regulatory cell activity, infections and infestations such as helminthiasis, and exposure to environmental xenobiotics with relevant diffusion in developing countries.
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