AI can empower agriculture for global food security: challenges and prospects in developing nations.

Food and nutrition are a steadfast essential to all living organisms. With specific reference to humans, the sufficient and efficient supply of food is a challenge as the world population continues to grow. Artificial Intelligence (AI) could be identified as a plausible technology in this 5th industrial revolution in bringing us closer to achieving zero hunger by 2030-Goal 2 of the United Nations Sustainable Development Goals (UNSDG). This goal cannot be achieved unless the digital divide among developed and underdeveloped countries is addressed. Nevertheless, developing and underdeveloped regions fall behind in economic resources; however, they harbor untapped potential to effectively address the impending demands posed by the soaring world population. Therefore, this study explores the in-depth potential of AI in the agriculture sector for developing and under-developed countries. Similarly, it aims to emphasize the proven efficiency and spin-off applications of AI in the advancement of agriculture. Currently, AI is being utilized in various spheres of agriculture, including but not limited to crop surveillance, irrigation management, disease identification, fertilization practices, task automation, image manipulation, data processing, yield forecasting, supply chain optimization, implementation of decision support system (DSS), weed control, and the enhancement of resource utilization. Whereas AI supports food safety and security by ensuring higher crop yields that are acquired by harnessing the potential of multi-temporal remote sensing (RS) techniques to accurately discern diverse crop phenotypes, monitor land cover dynamics, assess variations in soil organic matter, predict soil moisture levels, conduct plant biomass modeling, and enable comprehensive crop monitoring. The present study identifies various challenges, including financial, infrastructure, experts, data availability, customization, regulatory framework, cultural norms and attitudes, access to market, and interdisciplinary collaboration, in the adoption of AI for developing nations with their subsequent remedies. The identification of challenges and opportunities in the implementation of AI could ignite further research and actions in these regions; thereby supporting sustainable development.

Anapole state revealed by cloaking metallic cylinders with split ring resonators.

This paper proposes the experimental demonstration of an anapole-based cylindrical electromagnetic cloaking scheme. An anapole state is excited by arranging around a cylindrical metallic target vertical split-ring resonators, forming an equivalent surface admittance boundary condition able to suppress the scattering. Using Mie formalism and multipole scattering theory, we identify the actual reason behind the cloaking operation, characterizing the anapole condition by the scattering contributions from toroidal and electric dipole moments. Numerical results are verified using full-wave simulation softwares and subsequently validated with back-scattering measurements inside an anechoic chamber.

Generalized surface admittance equivalence principle for super-scattering in dielectric particles.

A general formulation for controlling the external scattering coefficients of cylindrical harmonics is presented, generalizing previous results for cloaking of a bare dielectric particle. By inserting a suitable surface admittance at the boundary between a dielectric body and the background region, cylindrical harmonic waves can be enhanced by tailoring the admittance value. Two separate limiting cases for super-scattering features are presented and compared against the same bare particle reference case, providing insights on how to enhance the multi-harmonic scattering pattern. Using this formulation, super-scattering systems can be created, which are suitable for future implementation using active or passive thin metasurfaces.

Fragmented blind docking: a novel protein-ligand binding prediction protocol.

In the present paper we propose a novel blind docking protocol based on Autodock-Vina. The developed docking protocol can provide binding site identification and binding pose prediction at the same time, by a systematical exploration of the protein volume performed with several preliminary docking calculations. In our opinion, this protocol can be successfully applied during the first steps of the virtual screening pipeline, because it provides binding site identification and binding pose prediction at the same time without visual evaluation of the binding site. After the binding pose prediction, MM/GBSA re-scoring rescoring procedures has been applied to improve the accuracy of the protein-ligand bound state. The FRAD protocol has been tested on 116 protein-ligand complexes of the Heat Shock Protein 90 - alpha, on 176 of Human Immunodeficiency virus protease 1, and on more than 100 protein-ligand system taken from the PDBbind dataset. Overall, the FRAD approach combined to MM/GBSA re-scoring can be considered as a powerful tool to increase the accuracy and efficiency with respect to other standard docking approaches when the ligand-binding site is unknown.Communicated by Ramaswamy H. Sarma.

SARS-CoV-2 infection serology validation of different methods: Usefulness of IgA in the early phase of infection.

BACKGROUND AND AIMS: A novel coronavirus (SARS-CoV-2) was isolated from the respiratory samples of patients with pneumonia as showed by the sequence analysis of the virus genomes obtained in Wuhan, China. The antibody response to SARS-CoV-2 is not well understood yet, but the availability of sensitive and specific serological assays will be crucial for the early diagnosis of infection, for epidemiological studies and for defining the presence of neutralizing antibodies in response to a possible vaccine. MATERIALS AND METHODS: We tested and compared the performances of one chemiluminescent immunoassay (CLIA), two enzyme-linked immunosorbent assay (ELISA) and an electrochemiluminescence immunoassay (ECLIA). RESULTS: The ECLIA serological assay performed best and may be a valid screening method for SARS-COV-2 infection. The IgA detected by the ELISA assay might be a more reliable and stable early serological marker than IgM. Instead, IgGs, as expected, showed stable level after 10 days from symptoms onset. CONCLUSION: The ECLIA method could be used as screening test, considering both the excellent performance and the cost per single test; while ELISA assay for IgG and IgA, which are present at a higher level than IgM and last longer, might be used as confirmatory test.

Nonradiating anapole condition derived from Devaney-Wolf theorem and excited in a broken-symmetry dielectric particle.

In this work, we first derive the nonradiating anapole condition with a straightforward theoretical demonstration exploiting one of the Devaney-Wolf theorems for nonradiating currents. Based on the equivalent volumetric and surface electromagnetic sources, it is possible to establish a unique compact conditions directly from Maxwell's Equations in order to ensure nonradiating anapole state. In addition, we support our theoretical findings with a numerical investigation on a broken-symmetry dielectric particle, building block of a metamaterial structure, demonstrating through a detailed multiple expansion the nonradiating anapole condition behind these peculiar destructive interactions.

Validation of a novel 3D flow model for the optimization of construct perfusion in radial-flow packed-bed bioreactors (rPBBs) for long-bone tissue engineering.

Osteogenic cell culture in three-dimensional (3D) hollow cylindrical porous scaffolds in radial-flow packed-bed bioreactors (rPBBs) may overcome the transport limitations of static and axial perfusion bioreactors in the engineering of long-bone substitutes. Flow models of rPBBs help optimize radial flux distribution of medium and tissue maturation in vitro. Only a 2D model is available for steady flow transport in rPBBs with axisymmetric inlet and outlet accounting for the fluid dynamics of void spaces, assessed against literature information. Here, a novel 3D model is proposed for steady flow transport in the three compartments of rPBBs with a more practical lateral outlet. A 3D model of transient tracer transport was developed based on the flow model to predict bioreactor residence time distribution (RTD). Model-predicted flow patterns were validated in terms of RTD against tracer experiments performed with bioreactor prototypes equipped with commercial scaffolds for bone tissue engineering. Bioreactors were challenged with a step change in entering tracer concentration in an optimized set-up under conditions promoting uniform radial flux distribution and typical shunt flows. Model-predicted RTDs agreed well with those experimentally determined. In conclusion, tracer experiments validate the use of the 3D flow model for optimizing construct perfusion in rPBBs to engineer long-bone substitutes.

Multipolar passive cloaking by nonradiating anapole excitation.

In this paper, we demonstrate the relation between cloaking effect and its nonradiating state by considering the destructive multipolar interaction between near-field scattering by bare object and surrounding coating located in its proximity. This cloaking effect is underpinned by anapole mode excitation and it occurs as destructive interference between the electric dipole moment, generated by a bare object (here a central metallic scatterer) and the toroidal moment, formed inside the cloak (a surrounding cluster of dielectric cylinders). Numerical results show how a cloaking effect based on the formation of the anapole mode can lead to an overall nonradiating metamolecule with all-dielectric materials in the coating region.

Development of a Device-Assisted Nerve-Regeneration Procedure in Disruptive Lesions of the Brachial Plexus.

BACKGROUND: We describe the development of a new surgical procedure to be used in the treatment of disruptive brachial plexus (BP) lesions. It is centered on an artificial device designed to assist nerve regeneration by providing a confined and protected environment. Nerve fibers can repair inside the device, while the adverse massive scar-tissue formation is limited to the outside of the device. METHODS: Steps in the development of the procedure were (1) definition of the rationale, (2) design of the device, (3) choice of an in vivo translational model, (4)refinement of the surgical procedure, and (5) performance of an in vivo pilot study as a proof of concept. An interdisciplinary team from several laboratories was involved in this work over a period of 6 years. RESULTS: Results showed the absence of significant scar tissue in the regenerate and the presence of myelinated fibers aligned proximodistally between the stumps. This surgical approach can be seen not only as a definitive treatment but also as an early examination and stabilization before some different surgery will be later performed. It may also be used as additional protection for traditional surgery like end-to-end coaptation. CONCLUSIONS: We conclude that the availability of a suitable device-assisted early treatment, even if not to be considered definitive, could help in addressing the BP lesions at an earlier stage and this may improve the final outcome. Our evidence justifies further experimentation on this approach.

Towards Printable Natural Dielectric Cloaks via Inverse Scattering Techniques.

The synthesis of non-magnetic 2D dielectric cloaks as proper solutions of an inverse scattering problem is addressed in this paper. Adopting the relevant integral formulation governing the scattering phenomena, analytic and numerical approaches are exploited to provide new insights on how frequency and direction of arrival of the incoming wave may influence the cloaking mechanism in terms of permittivity distribution within the cover region. In quasi-static (subwavelength) regime a solution is analytically derived in terms of homogeneous artificial dielectric cover with ε < ε 0, which is found to be a necessary and sufficient condition for achieving omnidirectional cloaking. On the other hand, beyond quasi-static regime, the cloaking problem is addressed as an optimization task looking for only natural dielectric coatings with ε > ε 0 able to hide the object for a given number of directions of the incident field. Simulated results confirm the validity of both analytic and numerical methodologies and allow to estimate effective bandwidths both in terms of frequency range and direction of arrival of the impinging field.

Non-covalently crosslinked chitosan nanofibrous mats prepared by electrospinning as substrates for soft tissue regeneration.

Chitosan (CS) membranes obtained by electrospinning are potentially ideal substrates for soft tissue engineering as they combine the excellent biological properties of CS with the extracellular matrix (ECM)-like structure of nanofibrous mats. However, the high amount of acid solvents required to spun CS solutions interferes with the biocompatibility of CS fibres. To overcome this limitation, novel CS based solutions were investigated in this work. Low amount of acidic acid (0.5M) was used and dibasic sodium phosphate (DSP) was introduced as ionic crosslinker to improve nanofibres water stability and to neutralize the acidic pH of electrospun membranes after fibres soaking in biological fluids. Randomly oriented and aligned nanofibres (128±19nm and 140±41nm, respectively) were obtained through electrospinning process (voltage of 30kV, 30µL/min flow rate and temperature of 39°C) showing mechanical properties similar to those of soft tissues (Young Modulus lower than 40MPa in dry condition) and water stability until 7 days. C2C12 myoblast cell line was cultured on CS fibres showing that the aligned architecture of substrate induces cell orientation that can enhance skeletal muscle regeneration.

Mathematical modeling of intraperitoneal drug delivery: simulation of drug distribution in a single tumor nodule.

The intraperitoneal (IP) administration of chemotherapy is an alternative treatment for peritoneal carcinomatosis, allowing for higher intratumor concentrations of the cytotoxic agent compared to intravenous administration. Nevertheless, drug penetration depths are still limited to a few millimeters. It is thus necessary to better understand the limiting factors behind this poor penetration in order to improve IP chemotherapy delivery. By developing a three-dimensional computational fluid dynamics (CFD) model for drug penetration in a tumor nodule, we investigated the impact of a number of key parameters on the drug transport and penetration depth during IP chemotherapy. Overall, smaller tumors showed better penetration than larger ones, which could be attributed to the lower IFP in smaller tumors. Furthermore, the model demonstrated large improvements in penetration depth by subjecting the tumor nodules to vascular normalization therapy, and illustrated the importance of the drug that is used for therapy. Explicitly modeling the necrotic core had a limited effect on the simulated penetration. Similarly, the penetration depth remained virtually constant when the Darcy permeability of the tissue changed. Our findings illustrate that the developed parametrical CFD model is a powerful tool providing more insight in the drug transport and penetration during IP chemotherapy.

Invisibility and cloaking structures as weak or strong solutions of Devaney-Wolf theorem.

Inspired by a general theorem on non-radiating sources demonstrated by Devaney and Wolf, a unified theory for invisible and cloaking structures is here proposed. By solving Devaney-Wolf theorem in the quasi-static limit, a weak solution is obtained, demonstrating the existence of Anapole modes, Mantle Cloaking and Plasmonic Cloaking. Beyond the quasi-static regime, a strong solution of Devaney-Wolf theorem can be formulated, predicting general non-scattering devices based on directional invisibility, Transformation Optics, neutral inclusions and refractive index continuity. Both weak and strong solutions are analytically demonstrated to depend on the concept of contrast, mathematically defined as a normalized difference between constitutive parameters (or wave-impedance property) of a material and its surrounding background.

A Versatile Bioreactor for Dynamic Suspension Cell Culture. Application to the Culture of Cancer Cell Spheroids.

A versatile bioreactor suitable for dynamic suspension cell culture under tunable shear stress conditions has been developed and preliminarily tested culturing cancer cell spheroids. By adopting simple technological solutions and avoiding rotating components, the bioreactor exploits the laminar hydrodynamics establishing within the culture chamber enabling dynamic cell suspension in an environment favourable to mass transport, under a wide range of tunable shear stress conditions. The design phase of the device has been supported by multiphysics modelling and has provided a comprehensive analysis of the operating principles of the bioreactor. Moreover, an explanatory example is herein presented with multiphysics simulations used to set the proper bioreactor operating conditions for preliminary in vitro biological tests on a human lung carcinoma cell line. The biological results demonstrate that the ultralow shear dynamic suspension provided by the device is beneficial for culturing cancer cell spheroids. In comparison to the static suspension control, dynamic cell suspension preserves morphological features, promotes intercellular connection, increases spheroid size (2.4-fold increase) and number of cycling cells (1.58-fold increase), and reduces double strand DNA damage (1.5-fold reduction). It is envisioned that the versatility of this bioreactor could allow investigation and expansion of different cell types in the future.

Bone structural similarity score: a multiparametric tool to match properties of biomimetic bone substitutes with their target tissues.

BACKGROUND: One of the hardest tasks in developing or selecting grafts for bone substitution surgery or tissue engineering is to match the structural and mechanical properties of tissue at the recipient site, because of the large variability of tissue properties with anatomical site, sex, age and health conditions of the patient undergoing implantation. We investigated the feasibility of defining a quantitative bone structural similarity score based on differences in the structural properties of synthetic grafts and bone tissue. METHODS: Two biocompatible hydroxyapatite porous scaffolds with different nominal pore sizes were compared with trabecular bone tissues from equine humerus and femur. Images of samples' structures were acquired by high-resolution micro-computed tomography and analyzed to estimate porosity, pore size distribution and interconnectivity, specific surface area, connectivity density and degree of anisotropy. Young's modulus and stress at break were measured by compression tests. Structural similarity distances between sample pairs were defined based on scaled and weighted differences of the measured properties. Their feasibility was investigated for scoring structural similarity between considered scaffolds or bone tissues. RESULTS: Manhattan distances and Quadrance generally showed sound and consistent similarities between sample pairs, more clearly than simple statistical comparison and with discriminating capacity similar to image-based scores to assess progression of pathologies affecting bone structure. CONCLUSIONS: The results suggest that a quantitative and objective bone structural similarity score may be defined to help biomaterials scientists fabricate, and surgeons select, the graft or scaffold best mimicking the structure of a given bone tissue.