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Matteo Vicini1,a*, Paola Folegati2,b, Rafael Ferragut2,3,c and Claudio Conci1,d* 1Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy 2Department of Physics and L-NESS, Politecnico di Milano, Via Anzani, 42, 22100 Como, Italy 3INFN, Sezione di Milano, Via Celoria 16, 20133 Milano, Italy amatteo.vicini@polimi.it, bpaola.folegati@polimi.it, crafael.ferragut@polimi.it, dclaudio.conci@polimi,it Keywords: Positron Annihilation Spectroscopy, Positron Emission Tomography, Diagnostics, Medical Imaging, Magnetic Resonance Imaging, Computed Tomography Abstract: Positron annihilation spectroscopy (PAS) offers a transformative approach to medical imaging, providing detailed insights into molecular structures.
Even though PAS has been widely used for studying defects in metals alloys and semiconductors [16-18] and synthetic materials [19-21] providing quantitative data about the microscopic structure and properties of these substances, its potential application in medical imaging could mark a significant turning point, promising to revolutionize diagnostic methodologies.
(2) Where α is the fine-structure constant (~1/137) and X0 a given penetration depth.
By analyzing positron lifetime and annihilation momentum, PAS can provide critical insights into the nanoscale structure of tissues, including aspects such as free volume, the presence of free radicals, reactive oxygen species (ROS), and hypoxic conditions.
Ferragut, Structure evolution of EV31 MG alloy, J.

The GIC material is the restoration material that can be attached to the enamel and dentin on a physico-chemical basis.[1] The tooth-colour restoration material on the GIC restoration material can be used for the restoration of cavities with low pressure of mastication.[2] Benefits of GIC material physico-chemistry with its dental structure and application requires a relatively short time.[3] The GIC material is widely used in dentistry today due to its chemical properties, which bind to good dental structures or enamel.
The negatively charged phosphate ions [PO43-] and positively charged calcium ions [Ca2+] shift from the tooth structure (hydroxyapatite) and into the cement, generating a layer between the GIC and the dental structures.
This can occur because even with silica modifications that have the same structure as the enamel and teeth can increase the density to the dental structure, the condensation of the silica modification is allegedly uneven (Figure 5).
It has therefore been done a series of modifications to enhance its mechanical structure.
The attachment between the dental structure and the GIC is conditioned with the help of dentin conditioner.

Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague 8, Czech Republic.
Thus prepared materials exhibited well organized mesoporous structure, without the inorganic stabilizer.
Polystyrene spheres with uniform diameter (dp) form opal-like close packed structures (mostly fcc).
Organized structures: S-peaks.
This structure is responsible for peculiar Li-insertion properties described above.

The structure of the nano-calcium carbonate before and after silver loading was analyzed using a Bruker Advanced-D8 powder diffractometer.
This structure can also promote the synergistic absorption of CaCO3 and nanosilver.
Studies have shown that shows that the cell wall structure and surface chemical composition of Escherichia coli and Staphylococcus aureus are very different, and the cell wall structure of Escherichia coli is complex.
This is related to the special electronic layer structure of rare earth elements.
The Journal of Physical Chemistry Letters, 10(2) (2019) 223-228

The cores of magnetic bead were extensively characterized in terms of size, surface chemistry, nontoxicity, and magnetic properties.
Also, the functional magnetic bead structure with specific coating acts as a charged solid surface to bind nucleic acid fragments.
Chaotropic agents can break the structure of water and make it less hydrophilic and thereby weakening the hydrophobic interactions.
Tang, Preparation, structure, and magnetic properties of polystyrene coated by Fe3O4 nanoparticles, J.
Pusz, Iron oxides/graphene hybrid structures – Preparation, modification, and application as fillers of polymer composites, Adv.

Thus, the structure of individual concrete compositions is compacted because of reduced Wmin value, and in some cases – the exact opposite, the structure begins to gradually become rickety.
The nonlinear ES-model (refer with: Eq. 1) is structured by groups of factors.
Sheikin, Structure, durability and crack resistance of cement stone, Мoscow, Stroyizdat, 1974
Li, The chemistry of cement and concrete, Мoscow, Stroyizdat, 1961
Hlitsov, Experiment planning in the study of decorative sand concrete, Structure formation, strength and destruction of composite building materials and structures, OGASA, Odessa, 2018, pp. 27-30

The obtained results demonstrate that the structure of the proposed film was nanocrystalline.
Herein, we investigate the morphology, crystallographic structure and the chemical composition of Al2O3 particles deposited with nano Mn by using the wet impregnation method.
Structure, particle size, surface and morphology of the proposed Al2O3-Mn were examined and analyzed by XRD, TGA, AAS and FESEM characterization techniques.
The characterization results clearly demonstrate the formation of high purity of Al2O3-Mn with small particle size, high surface area and no obvious change in hexagonal structure.
Zaharescu., Structure and dielectric properties of HfO2 films prepared by a sol–gel route, J.

As we all know, coal is a complex organic molecules and chemical bonds by a variety of functional groups as well as the disorder structure caused by the nature of the complex structure of variability [3].
As ordered domains and orientation of the macromolecular structure of the coal increases, the basic structural unit is more intensive.
Rapid development of the rank of physics and chemistry results in the microcrystalline structurein ordered carbon material [6].
Furthermore, the structure and morphology, phase composition and internal functional groups, such as the migration process, were tested and characterized.
Bituminous surface heat-treated 2200℃ ~ 2600℃ obvious extension of the crystal orientation of the structure and development tends to be entire.

In these cases, it is the source of its own, which is referred to such bodies or substances in which structure is formed light.
In this case, it is the source as itself, which refers to body or substance structures in which light is formed.
Thermal structure of the flame is composed of extremely steep temperature gradients composed of different high temperatures for short distances.
It is also necessary to ensure an adequate air exchange in areas with large quantities of candles to prevent health problems arising from the inhalation of released impurities into the air and chemical reactions on the surface of materials that may interfere with their structure and durability.
Accessible from: http://www.science.nasa.gov [11] The Physics and Chemistry Underlying the Infinite Charm of a Candle Flame (By Jearl Walker.

In recent years, several attempts have been made to characterize the geometric structure of fullerenes by means of topological shape factors in order to predict their physical properties and stability.
(19) In the following we will show that the moments µm(ΦS) calculated from generalized combinatorial curvatures ΦS(Xj) can be efficiently used to characterize the topological structures of fullerene-like molecules. 4.
This is explained by the fact that several topological descriptors have been already calculated for C60 and C40 isomers: the pentagon adjacency index NP [1,6, 9,14], the Wiener index WI [10], the resistance distance RT [10], the isolation index IS [ 25], the Aboav parameter AR [26], the Kekulé structure count [11], the graph independence number [12], the number of spanning trees [13].
J. of Quantum Chemistry, Vol. 84 (2001) p. 136-139
Böröczky: Topological Characterization of Cellular Structures, Acta Polytechnica Hungarica, Vol.1 (2004) p. 59-85