261 research outputs found
Polymer-physics modeling to explore single-cell DNA architecture and characterize experimental methods
The comprehension of the spatial organization of chromosomes in mammal cells is a major challenge for contemporary biophysics, as it is connected with the
functionality of the genome. For that reason, sophisticated technologies have been designed to explore the chromosomal architectures, while polymer-physics models have been proposed to make sense of the experimental observations and to identify the molecular
mechanisms driving the folding of DNA. Here, we present a polymer-physics model which can explain the conformations of DNA observed in human cells, based on the phase-separation mechanism of classical polymers and on the corresponding thermodynamic degeneracy of states. Additionally, we show that model polymer structures of real chromosomal regions can be used to benchmark, computationally, the performances of different experimental technologies able to capture the architecture of chromosomes (Hi-C, GAM and SPRITE). We will illustrate that such approach allows to quantitatively compare the experimental technologies and, so, define the optimal experimental setup for various possible conditions
Automated Mapping of the roof damage in historic buildings in seismic areas with UAV photogrammetry
The paper presents a fast methodology to quantify the damage to the roof in historic buildings, suggested soon after a light seismic event occurs, in order to evaluate the necessity of provisional interventions to prevent further damages. The survey is based on UAV photogrammetry, a well-known technique that allows inspection and digital documentation even in hardly accessible or dangerous areas. The research aims to analyze the feasibility of the automated mapping of roof damage using an image classification procedure based on supervised machine learning. The procedure is summed up in an efficient workflow, where UAV photogrammetry is combined with other 3D survey techniques, such as terrestrial photogrammetry and laser scanning, to provide comprehensive documentation and quantitative data on a historical building. The methodology was validated on a large historical building, now suffering from a serious state of neglect, which roof was never surveyed before and with different damage types. The output orthoimage of the tiled roof allowed us to understand the past interventions and the current serious damage state with promising outcomes regarding the speed of the survey method
MicroRNAs from saliva of anopheline mosquitoes mimic human endogenous miRNAs and may contribute to vector-host-pathogen interactions
During blood feeding haematophagous arthropods inject into their hosts a cocktail of salivary proteins whose main role is to counteract host haemostasis, inflammation and immunity. However, animal body fluids are known to also carry miRNAs. To get insights into saliva and salivary gland miRNA repertoires of the African malaria vector Anopheles coluzzii we used small RNA-Seq and identified 214 miRNAs, including tissue-enriched, sex-biased and putative novel anopheline miRNAs. Noteworthy, miRNAs were asymmetrically distributed between saliva and salivary glands, suggesting that selected miRNAs may be preferentially directed toward mosquito saliva. The evolutionary conservation of a subset of saliva miRNAs in Anopheles and Aedes mosquitoes, and in the tick Ixodes ricinus, supports the idea of a non-random occurrence pointing to their possible physiological role in blood feeding by arthropods. Strikingly, eleven of the most abundant An. coluzzi saliva miRNAs mimicked human miRNAs. Prediction analysis and search for experimentally validated targets indicated that miRNAs from An. coluzzii saliva may act on host mRNAs involved in immune and inflammatory responses. Overall, this study raises the intriguing hypothesis that miRNAs injected into vertebrates with vector saliva may contribute to host manipulation with possible implication for vector-host interaction and pathogen transmission
Occlusal Load Considerations in Implant-Supported Fixed Restorations
The advent of new technologies in the field of medicine and dentistry is creating improvements that lead clinicians to have materials and procedures able to improve patients' quality of life. The aim of this article is to evaluate occlusion load and its consequences on fixed implant-supported prosthesis. New materials have granted clinicians the possibility achieve great aesthetic results in dental prosthesis, and new procedures allow them to standardize and give precise and repeatable results, especially for the functional and long-term stability aspects of products. Some principles should be carefully evaluated and applied to every dental prosthesis; the evaluation of the forces and fitting of meso-structures to dental implants, an aspect that is often not well considered by clinicians, is the main focus of this article
FEM and Von Mises analysis on prosthetic crowns structural elements: evaluation of different applied materials
The aim of this paper is to underline the mechanical properties of dental single crown prosthodontics materials in order to differentiate the possibility of using each material for typical clinical condition and masticatory load. Objective of the investigation is to highlight the stress distribution over different common dental crowns by using computer-aided design software and a three-dimensional virtual model. By using engineering systems of analyses like FEM and Von Mises investigations it has been highlighted the strength over simulated lower first premolar crowns made by chrome cobalt alloy, golden alloy, dental resin, and zirconia. The prosthodontics crown models have been created and put on simulated chewing stresses. The three-dimensional models were subjected to axial and oblique forces and both guaranteed expected results over simulated masticatory cycle. Dental resin presented the low value of fracture while high values have been recorded for the metal alloy and zirconia. Clinicians should choose the better prosthetic solution for the teeth they want to restore and replace. Both prosthetic dental crowns offer long-term success if applied following the manufacture guide limitations and suggestions
TeV neutrinos and hard X-rays from relativistic reconnection in the corona of NGC 1068
The recent discovery of astrophysical neutrinos from the Seyfert galaxy NGC
1068 suggests the presence of non-thermal protons within a compact "coronal"
region close to the central black hole. The acceleration mechanism of these
non-thermal protons remains elusive. We show that a large-scale magnetic
reconnection layer, of the order of a few gravitational radii, may provide such
a mechanism. In such a scenario, rough energy equipartition between magnetic
fields, X-ray photons, and non-thermal protons is established in the
reconnection region. Motivated by recent three-dimensional particle-in-cell
simulations of relativistic reconnection, we assume that the spectrum of
accelerated protons is a broken power law, with the break energy being
constrained by energy conservation (i.e., the energy density of accelerated
protons is at most comparable to the magnetic energy density). The proton
spectrum is below the break, and above the break, with IceCube neutrino observations suggesting . Protons above the break lose most of their energy within the
reconnection layer via photohadronic collisions with the coronal X-rays,
producing a neutrino signal in good agreement with the recent observations.
Gamma-rays injected in photohadronic collisions are cascaded to lower energies,
sustaining the population of electron-positron pairs that makes the corona
moderately Compton thick.Comment: 8 pages, 3 figures, with Appendice
Magnetic loss, permeability, and anisotropy compensation in CoO-doped Mn-Zn ferrites
Mn-Zn ferrite samples prepared by conventional solid state reaction method and sintering at 1325 °C were Co-enriched by addition of CoO up to 6000 ppm and characterized versus frequency (DC â 1GHz), peak polarization (2 mT â 200 mT), and temperature (23 °C â 120 °C). The magnetic losses at room temperature are observed to pass through a deep minimum value around 4000 ppm CoO at all polarizations values. This trend is smoothed out either by approaching the MHz range or by increasing the temperature. Conversely, the initial permeability attains its maximum value around the same CoO content, while showing moderate monotonical decrease with increasing CoO at the typical working temperatures of 80 â 100 °C. The energy losses, measured by a combination of fluxmetric and transmission line methods, are affected by the eddy currents, on the conventional 5 mm thick ring samples, only beyond a few MHz. Their assessment relies on the separation of rotational and domain wall processes, which can be done by analysis of the complex permeability and its frequency behavior. This permits one, in particular, to calculate the magnetic anisotropy and its dependence on CoO content and temperature and bring to light its decomposition into the host lattice and Co2+ temperature dependent contributions. The temperature and doping dependence of initial permeability and magnetic losses can in this way be qualitatively justified, without invoking the passage through zero value of the effective anisotropy constant upon doping
Low-cost GPS/GNSS Real Time Kinematic receiver to build a cartographic grid on the ground for an archaeological survey at Piscina Torta (Italy)
The collection of samples and finds for archaeological surveys is traditionally based on the establishment of grids that allow the area under study to be discretized into generally square cells in order to allow a statistical assessment of the highest or lowest concentration of finds. Currently, such grids are implemented in a local coordinate system established by means of total stations or tape measures. We validated the capabilities of a low-cost GPS/GNSS Real Time Kinematic (RTK) receiver to build a grid during the intensive archaeological survey of the Piscina Torta site (Italy), in the framework of the Salt and Power project of the University of Groningen. We also tested not using a local grid but a cartographic grid (WGS84 UTM zone 33 N) and naming the single cells with the coordinates of one of its vertices. This approach is greatly facilitated by the recent availability of inexpensive RTK receivers with few centimetres accuracy, very small in size and weight and with hardware protected enough to be used in the field. This would facilitate the use and exchange of the data (e.g. about the materials collected in the cell) among the scientific community and can be thought of as a proposal for standardization
Low-cost GPS/GNSS Real Time Kinematic receiver to build a cartographic grid on the ground for an archaeological survey at Piscina Torta (Italy)
The collection of samples and finds for archaeological surveys is traditionally based on the establishment of grids that allow the area under study to be discretized into generally square cells in order to allow a statistical assessment of the highest or lowest concentration of finds. Currently, such grids are implemented in a local coordinate system established by means of total stations or tape measures. We validated the capabilities of a low-cost GPS/GNSS Real Time Kinematic (RTK) receiver to build a grid during the intensive archaeological survey of the Piscina Torta site (Italy), in the framework of the Salt and Power project of the University of Groningen. We also tested not using a local grid but a cartographic grid (WGS84 UTM zone 33 N) and naming the single cells with the coordinates of one of its vertices. This approach is greatly facilitated by the recent availability of inexpensive RTK receivers with few centimetres accuracy, very small in size and weight and with hardware protected enough to be used in the field. This would facilitate the use and exchange of the data (e.g. about the materials collected in the cell) among the scientific community and can be thought of as a proposal for standardization
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