- Published on 19 March 2021
This Focus Point covers twelve original papers obtained from advanced theoretical analysis, experimental, and numerical simulations in Cancer and HIV/AIDS research. Results include a randomized discrete logistic equation to describe the dynamics of breast tumor; a mathematical model of breast cancer involving a system of differential equations with piecewise constant arguments to analyze the tumor growth and chemotherapeutic treatment; a new stochastic HIV mathematical model; incorporation of the Beddington–DeAngelis incidence rate to a continuous-time HIV infection model with cure rate and full logistic proliferation; a model for the tumor and normal cell growth under the influence of carcinogenic agents, an immunomodulator and variable influx of immune cells; a within-host HIV dynamical model under the effect of cytotoxic T lymphocytes immune response; the study of the interaction between drug addiction and the contagion of HIV/AIDS; a system of fractional differential equations with delays and a new computational method based on hybrid functions and Legendre polynomials with application to immunodeficiency viruses systems; investigation of cervical cancer; an HIV/AIDS epidemic model under fractal-fractional-order derivatives; study of the dynamics of HIV-AIDS infection via a fractional order SICA system; and sufficient conditions for the stability of a system describing the growth of malignant tumors.
- Published on 29 January 2021
Building on previous studies of muon tomography techniques, this topical issue demonstrates a full-scale prototype for the technology, capable of determining the position of a small lead block within a large sensing area
Each year, billions of tons of goods are transported globally using cargo containers. Currently, there are concerns that this immense volume of traffic could be exploited to transport illicit nuclear materials, with little chance of detection. One promising approach to combating this issue is to measure how goods interact with charged particles named muons – which form naturally as cosmic rays interact with Earth’s atmosphere. Studies worldwide have now explored how this technique, named ‘muon tomography,’ can be achieved through a variety of detection technologies and reconstruction algorithms. In this article of EPJ Plus, a team headed by Francesco Riggi at the University of Catania, Italy, build on these results to develop a full-scale muon tomograph prototype.
- Published on 15 January 2021
Nonlinear waves have long been at the research focus of both physicists and mathematicians, in diverse settings ranging from electromagnetic waves in nonlinear optics to matter waves in Bose-Einstein condensates, from Langmuir waves in plasma to internal and rogue waves in hydrodynamics. The study of physical phenomena by means of mathematical models often leads to nonlinear evolution equations known as integrable systems. One of the distinguished features of integrable systems is that they admit soliton solutions, i.e., stable, localized traveling waves which preserve their shape and velocity in the interaction. Other fundamental properties are their universal nature, and the fact that they can be effectively linearized, e.g., via the inverse scattering transform, or reduced to appropriate Riemann-Hilbert problems. Moreover, solutions can often be derived by the Zakharov-Shabat dressing method, by Backlund or Darboux transformations, or by Hirota’s method. Prototypical examples of such integrable equations in 1+1 dimensions are the nonlinear Schrödinger equation and its multicomponent generalizations, the sine-Gordon equation, the Korteweg-de Vries and the modified KdV equations, etc. In 2+1 dimensions the most notable examples are the Kadomtsev-Petviashvili (KP) equations, and the Davey-Stewartson equations. The aim of this special issue is to present the latest developments in the theory of nonlinear waves and integrable systems, and their various applications.
- Published on 10 September 2020
New understanding of the electrical properties of graphene nanoribbons (GRBs), when bounded with aromatic molecules, could have significant benefits in the development of chemosensors and personalised medicine.
Graphene is a modern wonder material possessing unique properties of strength, flexibility and conductivity whilst being abundant and remarkably cheap to produce, lending it to a multitude of useful applications – especially true when these 2D atom-thick sheets of carbon are split into narrow strips known as Graphene Nanoribbons (GNRs). New research published in EPJ Plus, authored by Kristiāns Čerņevičs, Michele Pizzochero, and Oleg V. Yazyev, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, aims to better understand the electron transport properties of GNRs and how they are affected by bonding with aromatics. This is a key step in designing technology such chemosensors.
- Published on 24 July 2020
The Special Issue contains the articles which were presented at the International research and practice conference “Nanotechnology and Nanomaterials” (NANO-2018), which was organized by the Institute of Physics of NAS of Ukraine with the participation of the Yuriy Fedkovych Chernivtsi National University (Ukraine), University of Tartu (Estonia), University of Turin (Italy), Pierre and Marie Curie University – Paris 6 (France).
The Special Issue gathered high-level articles at the forefront of nanoscience research which is devoted to: the optical absorption by a nanosystem with dielectric quantum dots; the fabrication of crystalline Bi2TeO5 - Bi4Si3O12 - SiO2 nanocomposite; the existence of both size and “even-odd” effects for the lifetime of carbyne-based nanodevices consisting of two graphene sheets connected by a carbyne chain; the adsorption properties of the silica-titanium mixed oxide; the adsorption properties and application perspectives of BSA films as sensitive coatings for gas sensors; the properties of MgFe2O4; to the problem of band broadening of SPR; the structural studies concerning the formation of self-assembled indium deposited nanostructures on the (100) surface of In4Se3 layered semiconductor and the possibility of constructing the general dynamic properties of a conduction electron injected into graphene in the rectangular lattice approximation.
The Guest Editor, Olena Fesenko, hopes that this collection provides a quick overview on recent trends in this emerging field of research.
- Published on 23 April 2020
With the right approach, statistics can be used to reliably track the growth and fall in daily new cases of Covid-19 in China, raising hopes that similar approaches could more accurately predict the spread of the virus in other nations.
Efforts to contain the spread of the Covid-19 pandemic are now the top priority of governments across the globe. As they make these life-saving decisions, it is particularly crucial for policymakers to accurately predict how the spread of the virus will change over time. Through research published in EPJ Plus, Ignazio Ciufolini at the University of Salento, and Antonio Paolozzi at Sapienza University of Rome, identify a clear mathematical trend in the evolution of daily new cases and death numbers in China, and use the same curve to predict how a similar slowdown will unfold in Italy.
- Published on 01 April 2020
By treating meat as a network of flexible polymers surrounded by flowing moisture, computer models can accurately predict how much it will shrink when cooked.
Meat is no ordinary solid. Made up of complex networks of moisture-saturated proteins, it displays some intriguing physical properties when it is cooked. Several studies in the past have attempted to recreate this behaviour in computer simulations, but because this demands so much computing power, they have only achieved simplified, one-dimensional recreations of the process, which aren’t particularly accurate. In new research published in EPJ Plus, mathematicians led by Dr Hala Nelson at James Madison University show that by modelling meat as a fluid-saturated matrix of elastic proteins, which are deformed as the fluid moves, cooking behaviours can be simulated more precisely.
- Published on 17 January 2020
This special issue is related to the 3rd edition of the International Conference on Innovation in Art Research and Technology (inArt 2018) held in Parma (Italy). The Focus Point includes 20 excellent examples of the research works presented at the Conference. In particular, attention is focused on: non-invasive investigation techniques; new materials for restoration in compliance with the artifacts and the environment; products for the prevention of corrosion and of degradation; self-cleaning materials. The articles are devoted to the study of many different art objects and materials, including paintings (pigments, dyes, binders), textiles, manuscripts, buildings as well as building materials, metals, glasses, gems, bones and ivory. The analyzed objects span a huge time interval, ranging from antiquity (ancient Egypt) to contemporary art. Many different techniques are involved: spectroscopy in the different ranges of the electromagnetic spectrum (from infrared to X-rays); visible and electron microscopy; multispectral imaging; three-dimensional reconstruction, using instruments as handheld spectrometers, neutron sources or particle accelerators. Data treatment is also discussed, from databases to data integration and decision tools.
EPJ Plus Focus Point: Past and Present: Recent Advances in the Investigation of Ancient Materials by Means of Scientific Instrumental Techniques
- Published on 12 December 2019
This Focus Point introduces selected papers from the contributions presented at the 10th Congress of Italian Association of Archaeometry (AIAr) held in Turin (Italy) in February 2018, where a large parterre of Italian as well as International researchers shared their experiences on new and more consolidated analytical approaches on archaeological and artistic materials.
Different topics were addressed in the realm of cultural heritage, from characterisation and diagnostics to bioarchaeology and man-environment interaction. A strong focus was put on the comparison between non-invasive/non-destructive and micro-invasive methods in the study of different categories of objects, evaluating the pros and cons of each approach. Also a growing interest, accompanied by increasing technological skills, was registered for monitoring of environmental conditions to which the archaeological and artistic patrimony is subjected.
EPJ Plus Focus Point: Fractional Differential Equations in Physics: Recent Advantages and Future Direction
- Published on 20 November 2019
The Focus Point on “Fractional Differential Equations in Physics: Recent Advantages and Future Direction” presents some of the multiple open research directions within the dynamical field of fractional calculus and its applications. Traditional viewpoints together with fractional calculus models and techniques are used to provide the readers with a full picture of how dynamic and useful fractional calculus ideas are in treating the dynamics of complex phenomena arising from science and engineering. We hope that the research articles of this Focus Point will motivate young researchers to apply their original ideas for solving the multiple open problems within fractional calculus.