Recent progresses in nanotechnology have clearly shown that the incorporation of nanomaterials within concrete elements leads to a sensible increase in strength and toughness, especially if used in combination with randomly distributed short fiber reinforcements, as for ultra high-performance fiber-reinforced concrete (UHPFRC). Current damage models often are not able to accurately predict the development of diffuse micro/macro-crack patterns which are typical for such concrete structures. In this work, a diffuse cohesive interface approach is proposed to predict the structural response of UHPFRC structures enhanced with embedded nanomaterials. According to this approach, all the internal mesh boundaries are regarded as potential crack segments, modeled as cohesive interfaces equipped with a mixed-mode traction-separation law suitably calibrated to account for the toughening effect of nano-reinforcements. The proposed fracture model has been firstly validated by comparing the failure simulation results of UHPFRC specimens containing different fractions of graphite nanoplatelets with the available experimental data. Subsequently, such a model, combined with an embedded truss model to simulate the concrete/steel rebars interaction, has been used for predicting the load-carrying capacity of steel bar-reinforced UHPFRC elements enhanced with nanoplatelets. The numerical outcomes have shown the reliability of the proposed model, also highlighting the role of the nano-reinforcement in the crack width control. Nowadays, concrete results in being the most used construction material in building and civil engineering, due to its durability, affordability, high temperature resistance, and good compressive strength . Its limIn general, UHPC exhibits an increasing brittleness with the increase of compressive strength, but such a brittleness can be properly limited with the inclusion of discontinuous high-strength steel fibers. This addition is able to enhance both the ductility and the flexural strength of concrete ,6,7, andDespite the excellent mechanical properties offered by UHPFRCs, previous studies indicate that their flowability is negatively influenced by high values of the fiber content ,17 and tDefinitively, the improved flexural and compressive strength and fracture toughness properties of concrete provided by the nano-sized reinforcement, used in combination with other reinforcement types, led to the development of a new-generation concrete, consisting of a special UHPFRC enhanced with nanomaterials. However, despite extensive studies on the influence of nanomaterials on the mechanical properties of concrete and mortar are available in the literature, only a few experimental investigations on UHPFRCs enhanced with nanomaterials have been performed. Among these, some authors showed that, with a 0.3% of graphite nanoplatelets embedded in a UHPFRC element, an increase of 56% and 187% in the tensile strength and energy absorption capacity can be obtained, respectively . Other rDespite the great number of experimental studies, to the best knowledge of the authors, only a few works in the literature have been addressed to the investigation of nano-enhanced UHPFRCs from the computational point of view, essentially due to the severe separation of the spatial scales involved in the damage and/or fracture phenomena, resulting in the difficulty of incorporating the toughening effect of nano-reinforcement in the overall  constitutive behavior of concrete .More generally speaking, cracking processes in fiber-reinforced concretes (FRCs), mainly without nano-enhancements, have been simulated in the literature by means of a wide variety of numerical models and methods, based on either smeared or discrete fracture approaches, in which the improved ductility provided by the dispersed reinforcement has been accounted for by properly modifying the softening behavior of the adopted (bulk or interface) constitutive models.Smeared crack approaches, consisting of smearing any individual crack over a computational region with degraded material properties, work naturally with the continuum mechanics-based computational methods, such as the standard displacement-type finite element method, but inevitably lose the discrete nature of fracture. Among the existing smeared approaches, damage, plasticity, and combined damage/plasticity models have been successfully applied to FRC materials. These models usually adopt different regularization techniques able to prevent the well-known ill-posedness of the associated BVPs, such as those based on strain gradient  and micrInstead of modeling cracks in a smeared manner, discrete fracture approaches possess the advantage of describing cracks as individual discontinuity surfaces embedded in the computational domain, thus taking into account, in a detailed way, multiple crack initiation and propagation, crack coalescence, unilateral contact between crack faces with or without friction, debonding and other interacting nonlinear micro- or macro-scale phenomena occurring not only in cement conglomerates, but also in other brittle and ductile reinforced composite materials  are the most used for concrete-like materials, including FRCs. In this context, a variety of cohesive traction-separation laws have been proposed, able to account for the influence of embedded short fibers on the global fracture properties  of the resulting concrete ,48,49. IFrom the analysis of the current technical literature, it can be observed that the attention is mainly focused on the numerical simulation of simple laboratory-scale UHPFRC elements without considering accurately the additional strengthening effect of steel reinforcing bars required for real-life engineering applications. Indeed, a comprehensive computational framework able to accurately predict all the potential damage mechanisms in steel bar-reinforced nano-enhanced UHPFRC structures under both ultimate and service loading conditions seems to still be missing, probably due to the inherent difficulty of incorporating all the different steel/concrete interactions in the already complex constitutive behavior of damaged concrete with both micro- and nano-reinforcements.a diffuse interface modeling (DIM) approach, based on a cohesive finite element methodology, introduced by some of the authors in  for convan embedded truss model (ETM), used in synergy with a special sliding interface model, already adopted in ,53 for cThe present work may be regarded as an attempt to fill this gap, by proposing a novel integrated numerical model for steel bar-reinforced UHPFRC structures, including those enhanced with the incorporation of nanomaterials. The two main ingredients of this model, detailed in In the first part of the results , the maiThe second part of the numerical outcomes  is devotIn this section, the general theoretical formulation of the diffuse cohesive interface approach for concrete-like materials is recalled, with reference to the planar elasticity case, and the particular mixed-mode interface model adopted for nano-enhanced UHPFRC is described.N, and containing multiple discontinuity lines, which represent potential crack paths whose location is not known a priori. In this situation, all the internal mesh boundaries may be regarded as interfaces at which displacement jumps may occur, so that the variational formulation of the resulting equilibrium problem is written for a spatially discretized and split body.The general theoretical formulation underlying the adopted diffuse cohesive interface approach for concrete-like materials is presented, following the variational framework described in . This foh, depicted in uh denotes the (unknown) approximated displacement field, hU is the set of kinematically admissible approximated displacement fields, vh is the (arbitrary) virtual displacement field, and hV is the set of kinematically admissible variations of the approximated displacement field. In addition, C is the fourth-order elasticity tensor, whereas K denotes the second-order cohesive constitutive tensor, here assumed to be function of a finite set of scalar state (damage) variables id, being responsible for the irreversible behavior of the embedded cohesive interfaces.In detail, the original body Ω is replaced with its planar tessellation ΩK can be expressed in terms of normal and tangential cohesive stiffness terms, denoted as nK = nK(id) and sK = sK(id), respectively:I denotes the second-order identity tensor, and n is the unit normal vector to If not direct cross-coupling between normal and tangential deformation modes is assumed,  Γdh see b. It folIt is worth noting that, in concrete-like materials, being characterized by a quasi-brittle structural response with highly localized damage, only a small percentage of cohesive interfaces are cracked, whereas the remaining (undamaged) interfaces are worthless. It follows that the artificial compliance introduced by the elastic branch of these unnecessary interfaces negatively affects the mechanical response of the ideally uncracked body by seriously reducing its overall material stiffness. Such a compliance could be reduced by adopting sufficiently high interface stiffness parameters, and by considering, at the same time, some theoretical upper bounds for these parameters related to the need of avoiding any ill-conditioning of the tangent stiffness matrices in static analyses, as is well known in the literature ,55,56.E denotes the Young’s modulus of the bulk material, Lmesh is the average mesh size, and κ is a dimensionless stiffness parameter, imposed to be much greater than one to avoid any sensible artificial stiffness reduction. In particular, κ is set equal to 200 in this work. This value is coherent with what is suggested in the recent literature [In the present work, the normal and tangential stiffness parameters are assumed to be equal, and computed according to the following relation:terature ,57, and terature .In this section, the adopted traction–separation law (TSL) for nano-enhanced UHPFRC is presented. This is a trilinear softening model able to capture the tensile failure of fiber-reinforced concretes, initially proposed in  for funcThe adopted model also considers, in addition to the fracture resistance offered by the aggregate interlocking, the additional toughening effect of embedded discrete fibers, which is associated with a sensible enlargement of the fracture process zone size in (nano-enhanced) UHPFRC with respect to (nano-enhanced) UHPC without reinforcement. The first two linear descending branches of the adopted trilinear softening model for nano-enhanced UHPFRC are associated with the initial and total fracture energies of nano-enhanced UHPC, respectively, whereas the last descending slope is related to the additional energy required to debond and pull-out the fibers from the cement paste, corresponding to the difference between the total fracture energy of nano-enhanced UHPFRC and the total fracture energy of nano-enhanced UHPC, as shown in tf, initial fracture energy c, total fracture energy fw. The first four parameters refer to the bilinear softening model of the plain (nano-enhanced) UHPC, whereas the two latter ones define the last descending branch of nano-enhanced UHPFRC.The numerical calibration of this softening model requires the determination of the following six fracture parameters: tensile strength w2 is derived assuming that the kink point between the first and second descending branches of the TSL is characterized by a crack opening width w , please see [fw is estimated as fL/4, fL being the fiber length. Such a value corresponds to the estimated pull-out length for randomly distributed short fibers , and the function t(wmax) represents the TSL shown in t being the effective traction and wmax the maximum value of the effective displacement jump w attained over the entire deformation history.The associated complete mixed-mode intrinsic-type interface constitutive behavior, including the damage irreversibility and the frictionless unilateral contact conditions, reads as:tf and fracture energies fw is assumed to be insensitive to the incorporation of nanoplatelets within the concrete matrix and the fiber/matrix bond-slip behavior occurring at higher spatial scales, which are not interacting with the nanoscale level.In this work, the same traction–separation law has been applied to both normal and nano-enhanced UHPFRC . The effect of diffuse nano-reinforcement on the nonlinear softening response of the conglomerate consists of a sensible increase of both tensile strength Finally, it is worth noting that the above-described interface model is not suitable for hooked fibers and/or high fiber volume fractions, which are usually associated with a strain hardening behavior in the post-cracking stage, even accompanied with a secondary peak in the global traction–separation response ,50,59. HThis section is devoted to the presentation of the newly proposed numerical framework for the failure analysis of nano-enhanced UHPFRC structures, as well as of the related computational details. Such a framework is adapted from another integrated numerical model, previously introduced in  for convThis numerical model is composed of two distinct submodels: (a) a diffuse interface model (DIM) for the simulation of multiple cracking within the concrete phase, introduced in ; and (b)In particular, the adopted model is able to correctly simulate the so-called tension stiffening effect, which is related to the capability of sound concrete to sustain tensile stresses between adjacent primary cracks. To this end, the steel/concrete interface model plays a fundamental role in predicting the structural behavior of steel-bar reinforced UHPFRC members in their cracked stage, since the steel/concrete slip behavior strongly influences the distribution of bond stresses along the reinforcement bars, and, ultimately, both crack width and crack spacing values.cf being its mean compressive strength), s1 = 0.1 mm and s2 = 0.6 mm. The remaining parameters are taken from the original Model Code formula; thus, bτf, = 0.4bτ,max and s3 = 10 mm, coinciding with the distance between ribs. The interface behavior is completed by assuming a perfect steel/concrete bond in the normal direction, so that only the interfacial slip is regarded as an active degree of freedom.According to the adopted ETM, the reinforcing bars are modeled as elastic-plastic truss elements, which are connected to the concrete elements via special zero-thickness interface elements equipped with a bond-slip constitutive behavior, able to capture the steel/concrete interactions see a. The bocf depending on the content of the embedded nanomaterials, which corresponds to a modification of the maximum steel/concrete bond stress. In more detail, according to the adopted model, an increase in the content of embedded nanomaterials, and thus in the compressive strength of the resulting conglomerate, is associated with an increase in the bond strength with the interacting steel bars. In the present work, different mean compressive strength values for different nano-enhanced UHPC mixtures have been directly taken from the literature, as will be explained in It is worth noting that the influence of nano-reinforcement on the adopted bond-slip relation for nano-enhanced UHPFRCs is implicitly taken into account by assigning a variation to A fundamental aspect of the adopted ETM relies on the possibility for any crack propagating towards the reinforcing bars to cross the steel layer, as depicted in The proposed integrated numerical framework for the failure analysis of UHPFRC structures (with or without nano-enhancement) has been implemented within the commercial finite element environment COMSOL Multiphysics , chosen In this section, the main numerical results obtained via the adopted diffuse cohesive interface model for plain nano-enhanced UHPFRC are presented, with reference to a simulated flexural test which involves structural elements containing different volume fractions of graphite nanoplatelets (GNPs). The proposed numerical applications have the twofold role of calibrating the inelastic parameters of embedded interfaces and of assessing the numerical accuracy of the adopted fracture model, via suitable comparisons with available experimental results, shown in The present numerical simulations involve small-sized UHPFRC beam specimens subjected to a four-point bending test, analyzed in  from an b = 76 mm and h = 76 mm, whereas the total length and the span length of the beam are equal to L = 305 mm and l = 203 mm, respectively. Three mixtures of UHPFRC, containing 0.5% by volume of straight steel fibers with length fL = 13 mm and diameter D = 2 mm, have been used for the specimens considered in the next simulations: one mixture without nano-enhancement, which is taken as the control one and named as UHPFRC, and two mixtures containing 0.05% and 0.1% of GNP reinforcements, referred to as UHPFRC GNP 0.05% and UHPFRC GNP 0.1%, respectively. Both physical and mechanical properties of the GNP and steel fiber reinforcement are reported in The geometric parameters of the cross section are E = 40 GPa, taken from the uniaxial tensile test results reported in [ν = 0.2, as usually assumed for uncracked normal concretes. The adopted values of the inelastic constitutive parameters introduced in tf are directly taken from the uniaxial tensile test responses reported in [c values are obtained by means of a fitting procedure of the experimental load–displacement curves obtained for the four-point bending test analyzed in [c is assumed to be constant for all the mixtures, and the fracture energy values are adjusted to enforce a linear variation with the nanoplatelet content. The constant value for the CTODc is not intended as an exact value , but rather can be regarded as an average with respect to the considered range of variation for the GNP content. As expected, the estimated fracture energies The elastic bulk material parameters have been set as equal for all the three concrete mixtures, being assumed to be almost independent of GNP embedding at lower volume fractions. In particular, the adopted Young’s modulus is orted in , whereasorted in , whereaslyzed in  and repo−3 mm for the extrados point of the mid-span section. Moreover, all the numerical simulations have been performed under a plane stress assumption.To reduce the computational effort of the numerical analyses, the cohesive interface elements have been inserted only within the rectangular area highlighted in The structural responses numerically derived for the different UHPFRC mixtures, depicted in It is worth noting that the adopted diffuse cohesive methodology allows both nucleation and propagation of the main crack to be naturally predicted, as shown in The good agreement between the experimental and numerical loading curves for each investigated UHPFRC mixture underlines that the adopted traction–separation law, if suitably calibrated in terms of inelastic cohesive parameters, is reliable for determining the structural behavior of both normal and nano-enhanced UHPFRC elements with lower nanoparticle contents (up to 0.1% by volume). The percentage errors on the predicted load peak with respect to the experimental values are fully acceptable from an engineering point of view, being of 3.62%, 3.58%, and 4.51%, for the three mixtures UHPFRC, UHPFRC GNP 0.05%, and UHPFRC GNP 0.1%, respectively. Moreover, a slight local divergence between numerical and experimental results can be observed in the softening branch of the curves referring to the case of UHPFRC without nano-reinforcement, probably due to the occurrence of an unstable structural response in the experimental test, being associated with the appearance of dynamic effects , characterized by very high speeds of the main crack propagation.The numerical outcomes clearly demonstrate the ability of the proposed diffuse cohesive model for UHPFRC in capturing the effectiveness of the embedded reinforcement in the form of graphite nanoplatelets on the mechanical performances of small-scale structural elements, in terms of cracking resistance and fracture toughness. As a matter of fact, as known from the experiments and confirmed by numerical results, an increase in the GNP fraction leads to an increase of both the peak load and the energy absorption capacity, due to the increase in the bond strength between cement paste and steel fibers and between cement paste and fine aggregates, guaranteed by the additional work-of-fracture provided by embedded nanoplatelets. On the other hand, as illustrated in With the purpose of investigating the mesh influence on the fracture behavior predicted by the diffuse interface model, a sensitivity analysis is performed by varying the mesh size, with reference to the already examined control UHPFRC specimen . Both the elastic and inelastic properties of cohesive interfaces are those reported in The numerical analyses show that the global structural response in terms of load versus mid-span deflection curve, depicted in Finally, an investigation on the mesh sensitivity of the numerically predicted main crack path is illustrated in Nevertheless, despite the above-mentioned local deviations, the predicted main crack at the end of simulation has been found to be almost insensitive to the mesh in a global sense, being always directed along nearly vertical directions and comprised within the constant bending moment region, with an average trajectory located in the proximity of the mid-span section . Such an alleviated mesh dependency behavior is essentially found by virtue of the adoption of a Delaunay triangulation, which preserves the isotropic nature of fracture processes in concrete-like materials, without introducing any preferential crack path directions with no physical meaning.The above results can be regarded as a further validation step of the diffuse interface model proposed in  and, morIn this section, the load-carrying capacity of steel bar-reinforced UHPFRC elements enhanced with graphite nanoplatelets (GNPs) has been investigated by means of the numerical model described in The subsequent numerical analyses have been performed to evaluate the structural response of the same steel bar-reinforced UHPFRC beam configuration with and without GNP reinforcements. The related results in terms of global load-deflection curves, horizontal stress maps, and tensile stress trends along the lower reinforcement bars are reported in The numerical application of the proposed integrated framework for steel bar-reinforced UHPFRC consists of the simulation of four-point bending tests performed on different medium-sized steel bar-reinforced beams made with the UHPFRC mixtures already adopted in The main mechanical parameters of both UHPFRC and steel materials are listed in The computational mesh, consisting of 17,346 triangular elements with a maximum element size of 10 mm, has been generated by using a Delaunay triangulation algorithm to avoid any preferential crack path direction. As shown in −2 mm.Finally, all the steel reinforcements  are modeled as one-dimensional two-node elastic-plastic truss elements connected to concrete elements via special zero-thickness four-node bond elements, according to the embedded truss model sketched in This section is devoted to the presentation and subsequent discussion of the numerically predicted structural response of the considered steel bar-reinforced GNP-enhanced UHPFRC beams. Such a response in terms of total load versus mid-span deflection curves is reported in E = 31 GPa, Poisson’s ratio ν = 0.2, tensile strength tf = 2.1 MPa, initial fracture energy fG = 75 N/m, total fracture energy FG = 125 N/m, and critical crack tip opening displacement CTODc = 0.048 mm. The excellent agreement between the experimental and numerical results further confirms the reliability of the proposed numerical framework for the failure prediction of both RC and FRC structural elements.For comparison purposes, this figure also shows the experimental results reported in , represeAs expected, the loading curves referring to steel bar-reinforced UHPFRC beams (with and without GNP enhancement) show greater load-carrying capacities with respect to the conventional RC beam, with increasing strength values for increasing contents of embedded graphite nanoplatelets (from 0% to 0.1%).In particular, the typical trilinear behavior of steel bar-reinforced structural elements has been observed for all the analyzed cases. The first slope change coincides with the occurrence of early nonlinear phenomena, consisting of coalescence of concrete microcracks and subsequent macrocrack nucleation. After this, the second linear branch with reduced stiffness initiates after the crack saturation state is reached, being associated with multiple macrocrack propagation toward the upper side of the RC beam. Finally, the second slope change corresponds to the initiation of the yielding phase for lower steel rebars, after which a slight hardening is kept without the occurrence of any collapse until the end of simulation, stopped as the deflection reaches a prescribed value of 15 mm.The numerical results clearly show that the combination of micro- and nano-reinforcements  significantly improves the flexural behavior of UHPFRC beams, in terms of ultimate load and energy absorption. In particular, increments of 11% and 20% in the absorbed energy . In addition, the crack spacing for the three different mixtures has been measured at the same fixed load level of 65 kN, obtaining a mean value of 91 mm for the case without nano-enhancement and of 84 mm for both the nano-enhanced mixtures. A crack spacing reduction of 7.32% has been achieved with the introduction of nano-enhancement, while a non-relevant crack spacing reduction is observed for a GNP volume fraction equal to 0.1%, due to the fact that, for the analyzed configuration, such content of nano-reinforcement is associated with a diffuse micro-cracking within the concrete teeth between existing macro-cracks, without leading to the onset of new macro-cracks. Moreover, compared to the case without nano-enhancement, a beam deflection reduction equal to 13.2% and 27.7% has been achieved for the cases with GNP addition of 0.05% and 0.1%, respectively, highlighting an improvement of the overall mechanical performances in terms of increasing bending stiffness as the nano-reinforcement content increases.With the aim to investigate the cracking phenomenon under service conditions, in In The numerically predicted crack width and crack spacing reductions for GNP-enhanced concrete highlights the reliability of the proposed numerical framework for UHPFRCs in capturing the additional crack bridging effect provided by nanoparticles inserted into the concrete mixture, and, ultimately, its beneficial influence on the ductility properties of structural elements, being intimately related to their macro-cracking behavior.Furthermore, in Finally, the reported oscillating behavior of such stresses, with local maxima in proximity of fully developed cracks and local minima between two contiguous cracks, demonstrates the capability of the adopted embedded truss model as well as of the proposed steel/UHPFRC bond-slip model to correctly capture the stress transfer between steel and concrete phases, which is of fundamental importance for the accurate numerical simulation of tension stiffening phenomena.All of the obtained numerical results confirm the reliability of the proposed integrated numerical framework for the failure analysis of steel bar-reinforced nano-enhanced UHPFRC structures, but a complete validation of the present model is out of the scope of the present work, due to the limited amount of experimental data available in the literature, to the best knowledge of the authors. A more rigorous calibration of this model could be the object of future investigations, which could also be addressed for the development of a more general validation procedure, eventually involving additional experimental research activity on nano-enhanced UHPFRC structural elements.possibility to accurately predict multiple crack initiation and propagation phenomena within a rather standard and readily implementable displacement-type finite element setting;capability to preserve the discrete nature of fracture processes, and, therefore, to capture the real complex crack patterns, in terms of both crack spacing and crack widths, whose knowledge is of fundamental importance for the safety and serviceability assessment of UHPFRC structures, as well as for their fiber content optimization within the design process.In this work, an integrated numerical model relying on a diffuse cohesive interface approach is developed for tracing the structural response of steel bar-reinforced UHPFRC structures enhanced with nanomaterials. The main advantages of this model can be synthetized in the following points:In the first part of this work, a diffuse interface model for the failure analysis of UHPFRC has been applied to investigate the role of the content of embedded graphite nanoplatelets (GNPs) on its load-carrying capacity at both peak and post-peak stages, with reference to simply supported beams subjected to a four-point bending test. All the numerical outcomes have been validated by performing suitable comparisons with the available experimental results. A good accordance between numerical and experimental loading curves has been found, with a mean absolute percentage error on the peak load of only about 4%, by virtue of a proper calibration of the inelastic parameters of the embedded cohesive interfaces. Moreover, additional computations have been performed to investigate the mesh dependency effects on the global structural response and crack pattern. The related results have shown that, despite the  mesh-dependency of the numerically predicted crack paths, which is related to the unavoidable randomness in the mesh generation procedures, the  load–displacement curves are substantially independent of the adopted discretization.In the second part, the proposed integrated numerical model for UHPFRC, which incorporates the adopted diffuse interface model, has been applied to investigate the effect of nano-enhancement in steel bar-reinforced UHPFRC structures. To this end, a simulated four-point bending test on three medium-sized beams with different volume fractions of GNPs is considered. The numerical outcomes have demonstrated the reliability and the accuracy of the proposed model in predicting both the strengthening and toughening effects of embedded nanomaterials, in terms of global load–deflection responses and associated crack patterns. In particular, increases in the first yielding load level and absorbed energy up to 11% and 20%, respectively, are numerically predicted for hybrid micro/nano-reinforcements with the highest considered GNP content . Furthermore, the role of nanomaterials on the tension stiffening effect has been demonstrated, by analyzing both final crack patterns and associated stress distribution maps. From the numerical analyses, the addition of 0.05% and 0.1% of GNPs has led to crack width reductions of 14% and 31%, respectively, as well as to maximum axial stress reductions along steel rebars of about 11% and 23%, respectively, thus confirming the increased ductility of the enhanced UHPFRC, at least for small volume contents of nano-reinforcement.As a possible future perspective of this research, the proposed numerical framework for the failure analysis of nano-enhanced UHPFRC structures could be incorporated within a more general and cost-effective computational strategy involving  multiscale methodologies similar to those already proposed by some of the authors for lightweight aggregate concretes , fiber-


The World Health Organization (WHO) called for global action towards the elimination of cervical cancer. One of the main strategies is to screen 70% of women at the age between 35 and 45 years and 90% of women managed appropriately by 2030. So far, approximately 85% of cervical cancers occur in low- and middle-income countries (LMICs). The colposcopy-guided biopsy is crucial for detecting cervical intraepithelial neoplasia (CIN) and becomes the main bottleneck limiting screening performance. Unprecedented advances in artificial intelligence (AI) enable the synergy of deep learning and digital colposcopy, which offers opportunities for automatic image-based diagnosis. To this end, we discuss the main challenges of traditional colposcopy and the solutions applying AI-guided digital colposcopy as an auxiliary diagnostic tool in low- and middle- income countries (LMICs).Existing challenges for the application of colposcopy in LMICs include strong dependence on the subjective experience of operators, substantial inter- and intra-operator variabilities, shortage of experienced colposcopists, consummate colposcopy training courses, and uniform diagnostic standard and strict quality control that are hard to be followed by colposcopists with limited diagnostic ability, resulting in discrepant reporting and documentation of colposcopy impressions. Organized colposcopy training courses should be viewed as an effective way to enhance the diagnostic ability of colposcopists, but implementing these courses in practice may not always be feasible to improve the overall diagnostic performance in a short period of time. Fortunately, AI has the potential to address colposcopic bottleneck, which could assist colposcopists in colposcopy imaging judgment, detection of underlying CINs, and guidance of biopsy sites. The automated workflow of colposcopy examination could create a novel cervical cancer screening model, reduce potentially false negatives and false positives, and improve the accuracy of colposcopy diagnosis and cervical biopsy.We believe that a practical and accurate AI-guided digital colposcopy has the potential to strengthen the diagnostic ability in guiding cervical biopsy, thereby improves cervical cancer screening performance in LMICs and accelerates the process of global cervical cancer elimination eventually. The burden of cervical cancer remains an important indicator of global health inequality. There are estimated 569,000 new cases and 310,000 deaths annually, among which approximately 85% occurred in low- and middle-income countries (LMICs) . In highIn LMICs, colposcopy is widely used to detect CINs and guide cervical biopsy sites for women who had abnormal cytology, human papillomavirus (HPV) infections, and clinical symptoms of suspected cervical diseases , 9. ThouFirst, the diagnostic performance of colposcopy strongly depends upon the subjective experience of operators, which requires the operators to recognize, process, and compare the perceived changes of acetowhitening epithelium  with the known features/criteria. The colposcopy not only focuses on cervical imaging technique, but also involves chemical staining of cervical epithelial cell which is influenced by solution quality, operation, and observation ways; thus, there are substantial inter- and intra-operator variabilities in the agreement of colposcopic impressions and pathology, ranging from 52 to 66% –14.Second, due to the lack of experienced colposcopists in LMICs, the workload increases along with the expanded cervical cancer screening programs, exacerbating the diagnostic inaccuracy of colposcopy. Third, organizing colposcopy training courses should be viewed as an effective way to enhance the diagnostic ability of colposcopists, but implementing these courses in practice may not always be feasible to improve the overall diagnostic performance in a short period of time and may be difficult to scale across geographies. Besides, as the occurrence of cervical cancer is expected to decrease with HPV-vaccinated women entering the screening population, junior colposcopists will find it difficult to see many cases of high-grade cervical lesions or even cancer in clinical practice, which limits their accumulation of expertise and experience. Forth, although uniform diagnostic standards and strict quality control for colposcopy practice are released by relevant official organizations, many colposcopic practitioners due to the limited diagnostic ability and lacking professional training from LMICs are having a hard time to follow standardized recommendations to practice colposcopy examination, resulting in discrepant reporting and documentation of colposcopy impressions. Finally, the diagnostic performance of colposcopy may be adversely affected by changes in screening modality from cytology, cytology-HPV co-testing to primary HPV screening, since cervical lesions related to HPV infections are likely to be mild and harder to be identified than cytological abnormalities. In general, diagnosing cervical abnormalities is a great challenge for the colposcopists in LMICs.In LMICs like China, although convincing achievements have been achieved for cervical cancer prevention and control, many challenges still exist and need more innovative solutions . The smaAs health systems and hospitals are more digitally enabled, traditional binocular colposcopy is also moving towards digital colposcopy, enabling colposcopists to access high-definition cervical images for diagnostic analyses. Although digital colposcopy has increased the accuracy of cervical examinations, it remains suboptimal in clinical practice due to a high degree of inter- and intra-colposcopist variability. Recent advances in AI can provide solutions to overcome these unsolved colposcopic bottlenecks. The AI methods, such as the deep learning-based algorithms, can learn features of cervical lesions from annotated colposcopy images which can then be integrated into the digital for automated colposcopy. This approach can address the diagnostic subjectivity of traditional colposcopy and improve the objectivity and performance of colposcopy with dynamic digital imaging. Another benefit offered by AI is that it could report diagnostic results in real time; therefore, the integration of AI algorithm into colposcopy equipment could help colposcopists to improve clinical workflow in a busy colposcopy clinic. In addition, due to the imbalance of medical resources in urban and rural areas of LMICs, the availability of a cloud-based AI platform could narrow the gap in colposcopy diagnosis between tertiary hospitals and primary care hospitals. Therefore, we believe that the development and application of AI-guided digital colposcopy have an important role in optimizing colposcopy services and augmenting clinical imaging judgment and is expected to improve the diagnostic performance of colposcopy through the detection of CINs and guidance of biopsy sites. At the same time, it can also be used for educational purposes, i.e., a virtual assistant to train novice colposcopists as what expert colposcopists would do during fellowship training. The detailed diagnostic workflow is shown in Fig. In recent years, we have witnessed the rapid development of deep learning techniques, which have been widely used for medical imaging and achieved impressive performances in various tasks such as lung nodule detection in CT and pathological image classification , 17. At Simoes et al. explored artificial neural networks with 170 colposcopy images as a training and validation set, and the results showed an accuracy of 72.15% . Kim et Despite the promising performance of AI with colposcopy imaging, several challenges and obstacles remain for further development and application.Firstly, with the increasing demand for colposcopy imaging in LMICs, large-scale datasets of colposcopic images are generated by hospitals. However, these datasets are rarely well managed for labeling, annotation, classification, and quality control due to different types of colposcopy equipment used for data collection and non-uniform descriptive terminology in colposcopy practice, which makes it difficult for the data to be used for training and validating AI-guided digital colposcopy. The management of medical data is one of the main challenges for the development of AI models. The ultimate solution is to standardize colposcopy equipment and terminology; however, it is difficult for this alignment in a short time. Another reasonable strategy is to further improve the AI algorithms to enable them to deal with images of different origins and qualities.Secondly, in clinical practice, the dynamic changes of appearance of acetowhitening epithelium after the application of an acetic acid solution of 3–5% are viewed as the main diagnostic basis for colposcopists . HoweverThirdly, the current AI models lack the interpretation of diagnostic decisions. The black boxes of AI models decrease their convincingness to colposcopists. In fact, interpretability and explainability of AI models are necessary to assist clinical colposcopists and provide relevant recommendations, such as the severity of the cervical lesions, biopsy sites, and even specific diagnostic evidence. This will make it easier for colposcopists to accept these AI models in clinical practice and could even become a teaching tool in hospitals or medical schools.Last but not least, using AI models to diagnose a certain rare cervical disease or complex complications is still unreliable as a number of presentations are rare in clinical practice, which is usually insufficient for the training and validation of AI models. Thus, the concept of developing and applying AI models in clinical practice is to help colposcopists improve the diagnostic ability rather than replace them. The diagnostic results of the AI model are only used as a reference, and human colposcopists should continue to be responsible for the final result.To develop an effective and robust AI-guided digital colposcopy, we must select high-quality colposcopy images and quality-controlled pathology diagnoses as the training set to ensure its diagnostic accuracy and reliability. The structure of learning data is very complex, particularly in LMICs with an extremely imbalanced medical resource; thus, this leads to extensive information islands. It is necessary for data professionals to closely work with colposcopists to deal with raw data for image annotation, classification, and quality control. Moreover, due to the requirement of a large amount of data to develop an AI model, the risk of data privacy disclosure and data sharing becomes an important concern. It is necessary to enhance data management and system authority, desensitize data, and implement a comprehensive privacy standard to reduce the risk of personal privacy disclosure.The AI-guided digital colposcopy aims to assist colposcopists rather than replace them. Also, colposcopists should not rely on AI-guided digital colposcopy, especially for junior colposcopists. Otherwise, junior colposcopists may still have the risk of being replaced. Meanwhile, colposcopists should continuously improve their ability from AI-assisted model and find the problems in AI interpretation, rather than simply apply the AI-assisted technology. Admittedly, the combination of colposcopists and AI model could improve the diagnostic ability of colposcopy, augment clinical judgment, and eventually compensate for the lack of experienced colposcopy practitioners in LMICs. Although the AI model can make a correct image-based subjective diagnosis in some aspects, colposcopists often consider other cervical disease-related factors  and are better at integrating information to make decisions than machines. Currently, AI products play an auxiliary role in the field of medicine, for example, cancer screening, diagnosis, medical imaging recognition, disease rehabilitation, and treatment. But with time, the application will continue to expand as the AI models are being adapted to integrate and digest multimodality datasets. In addition, the function positioning remains unclear for the development and application of AI-guided digital colposcopy. At present, there are two main available choices of target development that have been used to classify colposcopy images. Some researches prefer to define the outcome based upon the colposcopic impression of high-grade or worse threshold for treatment. Others base the outcome on the low-grade or worse threshold to guide cervical biopsies for reducing missed CIN2+ diagnosis as much as possible, which is the current colposcopic bottleneck limiting the screening performance in LMICs. We urgently need a practice AI-guided digital colposcopy that assists colposcopists to guide cervical biopsy precisely as the top priority to improve diagnostic performance.The AI-guided digital colposcopy can be developed and applied by building an interdisciplinary team of epidemiologists, colposcopists, pathologists, AI engineers, and product engineers. The epidemiologists in the whole process should navigate the study design, provide decision support, and promote research and development. Also, when colposcopists can find the problems existing in the current AI-assisted model in clinical application, the frequent communication between colposcopists and AI engineers can promote the development of AI-guided digital colposcopy. This multidisciplinary integration from different professional talents will encourage and promote close cooperation between universities, cancer research institutes, hospitals, and medical enterprises to establish a new discipline. Finally, this innovative discipline will attract more advanced talents to implement innovations in the field of AI, drive the development of interdisciplinary subjects, and promote AI algorithm transformation into clinical application.Currently, there are deficient laws and regulations at the national level to regulate the development and application of medical AI technology, accountability sharing mechanisms, and supervision of data and privacy in most LMICs . The defColposcopy is rapidly transitioning into the digital era with substantial potential impact on developing AI. The combination of digital colposcopy and AI could bring exciting changes to the prevention of cervical cancer, although plenty of technical, ethical, and legal issues remain to be solved. AI-guided digital colposcopy could assist colposcopists to improve their diagnostic performance, optimize clinical workflow, and mitigate the pressure of colposcopists and hospitals. The construction of cloud platform-based AI-guided digital colposcopy could create a novel cervical cancer screening model and provide equal access to diagnostic tools for cervical cancer in any regions of LMICs. We hope all research institutes or universities should translate their AI algorithms into clinical application and public health service, which thereby boosts AI-guided digital colposcopy to enter the health market and accelerates the global target of elimination of cervical cancer.


Contact tracing is a public health measure implemented to control the spread and break the chains of transmission of an infectious disease. It is done by identifying, assessing, and managing people who have been exposed to an infectious disease to prevent onward transmission. We summarize findings from a rapid Cochrane review that included cohort and modelling studies to assess the benefits and harms of digital solutions for identifying contacts of confirmed positive cases of an infectious disease. The review included 12 studies, which assessed digital contact tracing for the following infectious diseases: Ebola, tuberculosis, pertussis and coronavirus disease 2019 (COVID-19). This review revealed low-certainty evidence of a decrease in secondary cases of the targeted infectious disease, if digital contact tracing was used. However, it is uncertain from the currently available evidence whether digital contact tracing would produce more reliable counts of contacts and reduce the time taken to complete contact tracing. Therefore, implementation of digital contact tracing in the context of the ongoing coronavirus pandemic in African countries should be accompanied by a robust monitoring and evaluation framework. There should be an evaluation and documentation of the benefits, cost-effectiveness, acceptability, feasibility, equity impacts, and unintended consequences of the intervention. COVID-19 is caused by the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), and spreads from person-to-person through droplet and contact transmission . StrategTracing individuals who have been in contact with infected people can be effective in limiting the spread of an infection and number of deaths . ImplemeIn this commentary, we highlight and contextualize the findings of a rapid Cochrane review by Anglemyer and colleagues, on the benefits, harms, and acceptability of personal digital contact tracing solutions for identifying contacts of an identified positive case of an infectious disease . DigitalThis review included a total of 12 studies comprising of six cohort studies that reported quantitative data and six modelling studies that reported on modelling of digital solutions for contacting tracing . Of the Investigations conducted in low- or middle-income countries revealed some advantages of digital contact tracing systems over their manual counterparts. These studies reported that contact tracing teams found digital systems simpler to use and generally preferred them over paper systems, they were less time consuming, improved accuracy with large data, and were easier to transport compared with paper forms. However, the digital systems had challenges, for an example, there were increased costs and internet access problems compared to paper systems. Concerning privacy, devices seemed to have provided privacy regarding users who were exposed or diagnosed of the disease, although there were risks of privacy breaches from snoopers if linkage attacks occurred, particularly for wearable devices. According to modelling studies, there was also low-certainty evidence regarding a decrease in secondary cases using digital contact tracing. One study estimated an 18% reduction in in secondary cases with digital contact tracing compared to self-isolation alone, and a 35% reduction with manual contact-tracing. The certainty of evidence was due to unclear stipulations of their models, and about their assumptions of the effectiveness of manual contact tracing, where they assumed that 95% to 100% of contacts would be traced.Although modelling studies have reported that digital solutions in combination with strong public health efforts can reduce epidemics, cohort studies provide very low certainty evidence that technology can give more reliable counts of contacts and reduce the time to complete contact tracing in real epidemic situations. This therefore implies that more research needs to be conducted to provide enough evidence about the effectiveness of digital contact tracing compared to manual or paper-based methods. In addition, there needs to be more research done in the low-and-middle income regions, especially in Africa, where health systems tend to be overwhelmed when faced with disease outbreaks. Despite the limitations in certainty of evidence, digital contact tracing could potentially be useful in curbing the spread of COVID-19 and other highly infectious diseases. Governments in African countries could leverage on the existing mobile technology resources available in their countries, while taking into account, concerns around access in resource limited settings and privacy.


Glial cells are crucial for the maintenance of correct neuronal functionality in a physiological state and intervene to restore the equilibrium when environmental or pathological conditions challenge central nervous system homeostasis. The communication between glial cells and neurons is essential and extracellular vesicles (EVs) take part in this function by transporting a plethora of molecules with the capacity to influence the function of the recipient cells. EVs, including exosomes and microvesicles, are a heterogeneous group of biogenetically distinct double membrane-enclosed vesicles. Once released from the cell, these two types of vesicles are difficult to discern, thus we will call them with the general term of EVs. This review is focused on the EVs secreted by astrocytes, oligodendrocytes and microglia, aiming to shed light on their influence on neurons and on the overall homeostasis of the central nervous system functions. We collect evidence on neuroprotective and homeostatic effects of glial EVs, including neuronal plasticity. On the other hand, current knowledge of the detrimental effects of the EVs in pathological conditions is addressed. Finally, we propose directions for future studies and we evaluate the potential of EVs as a therapeutic treatment for neurological disorders. The human central nervous system (CNS) is an extremely complex organ composed by billions of highly specialized cells. In this review, we focus on two main types of cells: neurons, electrically active cells, which form a complex circuitry for the transmission and the processing of information, and glial cells. Glia are spread throughout the CNS and are essential for its homeostasis. Glia comprise a heterogeneous population of cells with different structures, functions and origin, and play a key role in pivotal physiological conditions, by performing housekeeping functions  preconditioning can also reduce neuronal cell death -1β and IL-10, showing that EVs from astrocytes stimulated with ATP or anti-inflammatory IL-10 are enriched with proteins involved in neurite outgrowth, axonal guidance, synaptogenesis, and synaptic long-term potentiation -stimulated astrocytes release EVs that increase neuronal apoptosis after treatment with low concentrations of neurotoxins    and DM20, two abundant proteins of myelin which are produced by alternative splicing from the PLP gene  , present in early stages of AD-like pathology in mouse brains, promotes microglial pro-inflammatory activation and induces release of EVs that contain increased levels of pro-inflammatory miRNAs and decreased levels of anti-inflammatory miRNAs  transmission in PD. EVs isolated from the plasma of PD patients show higher total α-syn and α-syn oligomers levels, compared to healthy controls (Xia et al., All these observations suggest an important role of EVs in the transmission of pathogenic proteins, thus placing EVs as central contributors to the pathogenesis of neurodegenerative disorders. However, further studies to clearly understand EVs role in protein spreading, but also to shed light on how these proteins are internalized by the recipient cells, will be essential to guide future research to develop effective treatments able to block the pathological protein spreading.The EVs secreted from glial cells do not only have an impact on neurons but can target other glial cells. It has been reported that microglia uptake EVs released from astrocytes treated with morphine, leading to impaired phagocytosis (Hu et al., In vitro, the authors described how EVs from pro-inflammatory microglia favor differentiation of OPCs, but, when co-cultured with astrocytes, they block OPC maturation (Lombardi et al., Moreover, it is well-known that microglia strongly influence remyelination, with a predominant pro-regenerative phenotype essential for an efficient myelin repair after damage (Miron et al., Development of EV based therapeutics for neurological conditions, in which the crossing of the BBB has always represented an obstacle to overcome, has been recently under active investigation. Poor brain penetration of many drugs ranging from small molecules to bioactive proteins constitute a problem. Interestingly, Yuan et al. showed improved targeting of BDNF to the brain parenchyma when complexed with EVs, compared to free BDNF, highlighting the feasibility of using EVs as drug delivery vehicles (Yuan et al., Interestingly, neuroinflammation, induced by intracranial LPS injection, increases the distribution of EVs in the brain (Yuan et al., Whilst mainstream of studies have focused on using MSC-derived EVs as therapeutic vehicles (Xin et al., Taken together, these studies suggest that glia-derived EVs may have therapeutic potential. Yet, further studies are essential in order to understand the role of glial EVs in different pathological conditions. It is important to note that in some neurodegenerative diseases, such as AD and PD, glia-derived EVs may be detrimental in contributing to the spreading of misfolded proteins.In the last years, several studies have focused on the use of EVs as biomarkers to obtain information about the presence and/or the molecular evolution of neoplastic diseases (Le Rhun et al., Further studies are needed to deepen the knowledge on the roles of glia-derived EVs in neurodegenerative disorders and in CNS tumors, and to understand if they may potentially constitute an advantage when designing novel therapeutics.in vitro, but there are still methodological difficulties to study the EV biology in vivo. Thus, efforts should be put into development of new models and more powerful imaging and tracking methods to allow studies in vivo. In addition, special emphasis should still be placed for the development of standardized protocols, useful to promote harmonization among laboratories and to allow a tighter control for EV characterization, an essential requirement for all EV studies.In this review we have summarized the current knowledge on the involvement of glial EVs in the communication between CNS cells. These vesicles can transfer specific molecules that are involved in both physiological and pathological processes, having an impact on the function of the surrounding neurons and glial cells. Owing to the recent advances in high-throughput technology, the screening for RNAs and proteomic components of glial EVs have allowed the identification of several functionally relevant EV-associated molecules (Murgoci et al., CP wrote the manuscript and prepared the figures. NB contributed to manuscript writing, discussed ideas, and helped in the correction. IS contributed to manuscript writing. TM critically revised the manuscript. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Sudden cardiac death (SCD) is a devastating event which can also affect people in apparent good health, such as young athletes. It is known that intense and continuous exercise along with a genetic background that predisposes a person to the risk of fatal arrhythmias is a trigger for SCD. Therefore, knowledge of the athlete’s genetic conditions underlying the onset of SCD must be extended, in order to develop new effective prevention and/or therapeutic strategies. Arrhythmic features occur across a broad spectrum of cardiac diseases, sometimes presenting with overlapping phenotypes. The genetic basis of arrhythmogenic disorders has been greatly highlighted in the last 30 years, and has shown marked heterogeneity. The advent of next-generation sequencing has constantly updated our understanding of the genetic basis of arrhythmogenic diseases and is laying the foundation for precision medicine. With the exception of a few clinical cases involving a single athlete showing a highly suspected phenotype for the presence of a heart disease, there are few studies to date that analysed the applicability of genetic testing on cohorts of athletes. This evidence shows that genetic testing can contribute to the diagnosis of up to 13% of athletes; however, the presence of clinical markers is essential. This review aims to provide a reference collection on current knowledge of the genetic basis of sudden cardiac death in athletes and to review updated evidence on the effectiveness of genetic testing in early identification of athletes at risk for SCD. Sudden cardiac death (SCD) is defined, according to the European Society of Cardiology (ESC), as a non-traumatic, unexpected fatal event occurring within 1 h of the onset of symptoms, in an apparently healthy subject. In about half of cases, SCD occurs after symptoms, such as chest pain, wheezing and shortness of breath, racing heartbeat, palpitations, feeling dizzy or fainting. The term “cardiac” can be used if a potentially fatal cardiac condition, congenital or acquired, was identified or the autopsy showed cardiovascular abnormalities. Therefore, an arrhythmic event is the most probably cause of death ,3.https://www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults, accessed on 26 August 2020). However, in the presence of cardiovascular conditions predisposing to life-threatening ventricular arrhythmias, vigorous physical activity may transiently increase the risk of SCD, both in males and females, as evidenced by Corrado et al. in adolescents and young adults .,80.RYR2 Cardiomyopathies are a group of disorders in which the heart muscle is structurally and functionally abnormal in the absence of other diseases that could cause the observed myocardial abnormality . CardiomMYH7 and MYBPC3, encoding the sarcomeric proteins β-myosin heavy chain and cardiac myosin-binding protein C, respectively , while in 10% of HCM cases mutations in MYL2, MYL3, TPM1, TNNT2, TNNI3 and ACTC1 genes are reported ..47].In 2020, we found two papers related to the issue of clinical significance of genetic screening in athletes  48,50].,50.48,50SCD is a catastrophic event, which appears even more devastating when it affects the athlete, who in the collective imagination is the prototype of wellbeing and good health. It is a rare event, accounting for nearly 6% of the total SCDs both in agonist and amateur young athletes ,109,110.The correlation between the practice of physical activity, especially if strenuous and continuative, and the risk of sudden death, has been known since the end of the last century . TherefoAlthough a comprehensive clinical and instrumental evaluation, based on pre-participation screening and further additional instrumental investigations, can obtain a final diagnosis in a large portion of athletes, in some cases the differential diagnosis between myocardial disease and athlete’s heart is difficult. Therefore, the structural, functional and electrical remodeling of the athlete’s heart may lead to ECG, echocardiographic and CMR abnormalities, which may be difficult to differentiate from an inherited cardiac disease. In this subgroup of patients, genetic testing may be resolutive.The effectiveness of genetic testing in the pre-participation screening programme has aroused great interest in the world of clinical molecular biology, given the growing evidence that phenotypically silent mutations related to inherited channelopathies and cardiomyopathies can represent a predisposing factor for the appearance of fatal arrhythmias triggered by physical activity . TherefoThis review first highlighted the great genetic heterogeneity and complexity that characterizes the molecular basis of inherited channelopathies and cardiomyopathies related to SCD. This complexity imposes the need to refer to experts in the field of molecular cardiology, who can use the most advanced sequencing methods, such as NGS, to sequence multiple genes simultaneously, in the effort to reach the maximum genetic yield ,100,101.Our second aim was to review papers that used genetic testing to identify athletes at risk of developing a potential life-threatening cardiac disease, to verify the applicability of the genetic test in the healthcare of athletes, when the initial pre-participation screening highlights the presence of clear cardiomyopathy, or subtle evidence of clinical markers of inherited disease .To date, a limited number of papers have addressed this issue. Several papers reported a single case showing early expression and/or family history of cardiac disease. Genetic analysis, moved by a specific diagnostic suspicion, revealed the presence of a disease-causing variant, and the athletes were disqualified from further competitive sport due to the risk of future occurrence of ventricular arrhythmia.In the last five years, there has been increasing interest in verifying the roles of genetic testing in the healthcare of athletes at the population level. Some papers applied the genetic test in the diagnostic flow-chart of cohorts of athletes targeted for the evidence of ECG anomalies with/without clinical symptoms. These studies unveiled that the percentage of genotype-positive athletes is significant and contributes as an integrative diagnostic instrument in athletes selected on the basis of a strong clinical suspicion for inherited cardiac disease ,46,49,50Kadota et al., for the first time, used genetic testing to distinguish hypertrophic cardiomyopathy from the athlete’s heart in 102 Japanese athletes showing features of hypertrophy at ECG or at the chest radiograph . In presIn conclusion, the analysed papers, although still few in number, show that it is necessary to correctly select athletes eligible for genetic testing, on the basis of phenotypic feature, to obtain maximum clinical efficacy.The identification of specific DNA mutation(s) in athletes showing an overt cardiac disease or a subtle evidence of a cardiac inherited disease or family history of hereditary cardiac disorders/sudden cardiac death is an important step in the integrated flow-chart to reach a definitive diagnosis of channelopathies and cardiomyopathies in these subjects at risk of SCD. This issue represents a real application of predictive medicine in the field of such a dramatic event that could occur during intense physical activity, as is sometimes read about or learned in sports-related clinical practice.On the other hand, the advent of the NGS has provided an important tool in the molecular genetics of inherited cardiac diseases, providing a relatively inexpensive instrument with which to investigate a broad spectrum of genes involved in cardiomyopathy and ion channel disorders. However, this field is only starting to make substantial inroads.


Tumor progression is mediated by reciprocal interaction between tumor cells and their surrounding tumor microenvironment (TME), which among other factors encompasses the extracellular milieu, immune cells, fibroblasts, and the vascular system. However, the complexity of cancer goes beyond the local interaction of tumor cells with their microenvironment. We are on the path to understanding cancer from a systemic viewpoint where the host macroenvironment also plays a crucial role in determining tumor progression. Indeed, growing evidence is emerging on the impact of the gut microbiota, metabolism, biomechanics, and the neuroimmunological axis on cancer. Thus, external factors capable of influencing the entire body system, such as emotional stress, surgery, or psychosocial factors, must be taken into consideration for enhanced management and treatment of cancer patients. In this article, we review prognostic and predictive biomarkers, as well as their potential evaluation and quantitative analysis. Our overarching aim is to open up new fields of study and intervention possibilities, within the framework of an integral vision of cancer as a functional tissue with the capacity to respond to different non-cytotoxic factors, hormonal, immunological, and mechanical forces, and others inducing stroma and tumor reprogramming. Since the 1980s, cancer research has focused on developing new therapeutic agents targeting DNA alterations and the search for a suitable cure, rather than understanding cancer as an integrated system composed of several modules. To date, the ability of cancer cells to survive for a prolonged time is still incompletely understood. In this context, we are beginning to include the role of stem cells in the tumor evolution process and to point out cellular pathways as a physiological adaptive process like a “wound that never heals” [The majority of tumors have a heterogeneous cellular population, and the vision that cancer originates from clonogenic expansion from a single mutated cell could be classed as simplistic and inexact. Microscopic observation of tumors reveals a multicellular 3-dimensional complex tissue underlying developmental alterations and a variable degree of morphological, immunophenotypic, and genomic heterogeneity. Indeed, the strategy used until recently of targeting one gene/protein/process at a time has proved unsuccessful. The Cancer Genome Atlas (TCGA), a public repertoire of genomic, epigenomic, transcriptomic and proteomic data, available to anyone in the research community, that leads to improvements in the ability to diagnose, treat and prevent cancer, represents a remarkable feat ; howeverThe tumor microenvironment (TME), which surrounds and interacts with tumor cells including the extracellular matrix (ECM) elements, stromal cells, blood and lymph vessels, nerve fibers and the signaling molecules, has been put forward to provide a more complex overview of how cancers develop and progress ,5. ReseaThe concept of cancer as a disease based on tissues and not only on genetic alterations at the cellular level  opens thSeveral local factors that shape the immune response, the ECM, and the adaptive process of angiogenesis contribute to the TME and tumor evolution. Host factors such as intestinal dysbiosis, neurotransmitters/neurohormones implicated in stress response, host and tumor metabolism, infections, surgical and physico-chemical stimuli can also impact on treatment response, activate the hypothalamic–pituitary–adrenal (HPA) axis and increase the risk of metastasis ,12.Tumors cells become aggressive through different mechanisms, such as epithelial-mesenchymal transition (EMT), which provides cancer cells with invasion and motility properties. This suggests the utility of modulating EMT and the inverse process, the mesenchymal to epithelial transition (MET), at a clinical level  to reverAnalysis and insight into these processes could support stratifying tumoral heterogeneity at the morphological, immunophenotypic, and genetic level throughout the stroma thus allowing us to identify targetable features . Beyond The immunological landscape of the TME plays a pivotal role in tumor progression. Cancer immunotherapy has gained growing importance in the last decade and several therapeutic strategies are based on the reactivation of the immune system. However, most immunotherapies employed to date are administered systemically, leading to toxicity . TargetiThe reciprocal interaction between cancer cells and TME determines the recruitment, activation, and reprogramming of stromal, inflammatory, and immune cells  Figure . We haveCancer cells can downregulate the expression of endothelial adhesion molecules secreted into the TME and required for the transendothelial migration of leucocytes to diminish exposure to cytotoxic effector cells and evade the immunological response . In addiSeveral components of the TME have been shown to play a direct role in shaping the immune response. Cancer-associated fibroblast (CAF)-mediated ECM remodeling and fibrosis contribute towards an immunosuppressed and pro-tumorigenic TME by affecting the recruitment and function of various innate and adaptive immune cells . A denseGiven these findings, we suggest adding a systematic study of the relationship between ECM remodeling and the inflamed stromal components of the TME to the current characterization of the immune TME. In an attempt to methodize evaluation of the host immune response in regarding the TME, the Immunoscore assay quantifies immune cell density to predict patient prognosis and suggest clinical treatment . This taIn cancer both the protective mechanisms of the immune system and the protective influence of the NS are lost , leavingTME components such as nerve fibers are important tissue elements in defining the intra- and peritumoral neural milieu ,50,51. CMost human tumors express surface adrenergic receptors, which when activated by stress catecholamines play a role in facilitating tumorigenesis and tumor progression . In lungUnderstanding the interaction between cancer cells and NS is becoming indispensable for the development of new targeted therapeutic intervention. In cancer, the intestinal microbiota (IMB), the complex and dynamic population of microorganisms that live in the digestive tracts, is of two-fold importance: on the one hand, for its etiopathogenic role  and on tFusobacterium nucleatum in colorectal carcinoma tissue  or IFN-γ, the complement system, opsonization, and others. This observation implies that processes such as inhibition of immunosuppressive cells (such as macrophages) or modulation of factors affecting the immune system (such as the microbiota), ultimately affect lymphoid cell activity, and support a relationship between tumor and immunity, such as the so-called “cancer immunogram” . The mosThe enormous plasticity that enables tumor cells to modify their phenotype and function  combinedHost immune response composition and activity can be evaluated using predictive and prognostic tools such as the Immunoscore or TIME. The impact of immune cells such as B cells, natural killers, MDSC, macrophages, and T cells shows that tumors originating from different tissues are unique and possess a differentiated immune profile ,193. DueThe view of cancer as a metabolic disease points to sugar and fat consumption by the tumor, the importance of systemic support factors such as caloric restriction, entosis and autophagy, the role of the ketogenic diet, and mitochondrial metabolic therapy. PD-L1 can also regulate cancer cell metabolism through the mTOR pathway and extracellular glucose availability . MetabolRewiring different TME elements, including components of the nervous system, biotensegral structures at all body levels, and microbiota could constitute a starting point for novel therapies based on an extended oncology framework and an integral vision of cancer. Collectively, these observations invite us to rethink current oncological and pathological protocols and advance in our discovery of new biomarkers/tools to efficiently manage safe therapeutic follow-up.


This Special Issue is focused on breakthrough developments in the field of assistive and rehabilitation robotics. The selected contributions include current scientific progress from biomedical signal processing and cover applications to myoelectric prostheses, lower-limb and upper-limb exoskeletons and assistive robotics. In recent years, the use of robotics to help motor-disabled people has experienced a significant growth, mostly based on the development and improvement of biosensor technology and the increasing interest in solving accessibility and rehabilitation limitations in a more natural and effective way. For this purpose, biomedical signal processing has been combined with robotic technology, such as exoskeletons or assistive robotic arms or hands. However, efforts are still needed to make these technologies affordable and useful for end users, as current biomedical devices are still mostly present in rehabilitation centers, hospitals and research facilities. This Special Issue covers several of the recent advances in robotic devices applied to motor rehabilitation and assistance.The Special Issue has collected eight outstanding papers covering different aspects of assistance robotics and biosensors. The selected contributions cover several main topics related to assistance robotics, from the control of myoelectric prostheses to the rehabilitation and assistance of the lower and upper limbs. What follows is a brief summary of the scope and main contributions of each of these papers, provided as a teaser for the interested reader.Upper-limb transradial amputation is cause of severe disability, and a key technology to solve this issue is the use of prosthetic devices for motor substitution. A particular way of controlling these devices is through electromyographic (EMG) signals. In , a low-cOther issues that affect classification accuracy are evaluated in ,3. An adThe rehabilitation of the lower limb has been addressed using a variety of devices, from exoskeletons to walkers. Lower-limb exoskeletons are mainly used in gait rehabilitation. HYBRID is an ambulatory robotic gait trainer with movement induction and partial weight support . This deIn , the autIn upper-limb rehabilitation, the physiological interaction of the patient with the robotic device is critical. In , two dif


This paper aims to provide a perspective on data sharing practices in the context of the COVID-19 pandemic. The scientific community has made several important inroads in the fight against COVID-19, and there are over 2500 clinical trials registered globally. Within the context of the rapidly changing pandemic, we are seeing a large number of trials conducted without results being made available. It is likely that a plethora of trials have stopped early, not for statistical reasons but due to lack of feasibility. Trials stopped early for feasibility are, by definition, statistically underpowered and thereby prone to inconclusive findings. Statistical power is not necessarily linear with the total sample size, and even small reductions in patient numbers or events can have a substantial impact on the research outcomes. Given the profusion of clinical trials investigating identical or similar treatments across different geographical and clinical contexts, one must also consider that the likelihood of a substantial number of false-positive and false-negative trials, emerging with the increasing overall number of trials, adds to public perceptions of uncertainty. This issue is complicated further by the evolving nature of the pandemic, wherein baseline assumptions on control group risk factors used to develop sample size calculations are far more challenging than those in the case of well-documented diseases. The standard answer to these challenges during nonpandemic settings is to assess each trial for statistical power and risk-of-bias and then pool the reported aggregated results using meta-analytic approaches. This solution simply will not suffice for COVID-19. Even with random-effects meta-analysis models, it will be difficult to adjust for the heterogeneity of different trials with aggregated reported data alone, especially given the absence of common data standards and outcome measures. To date, several groups have proposed structures and partnerships for data sharing. As COVID-19 has forced reconsideration of policies, processes, and interests, this is the time to advance scientific cooperation and shift the clinical research enterprise toward a data-sharing culture to maximize our response in the service of public health. The BMJ, only 85 trials have been published as of October 21, 2020, despite the large number of trials that have been registered and reported as complete [The scientific community has made several important inroads in the fight against COVID-19. The pandemic has mobilized the global research community at an unparalleled scale . From thDuring this time, we have seen a large number of trials conducted without results being made available. It is likely that a plethora of COVID-19 trials have stopped early, not for statistical reasons but due to lack of feasibility . ReasonsTrials stopped early for feasibility are, by definition, statistically underpowered and thereby prone to inconclusive findings. Statistical power is not necessarily linear with the total sample size, and even small reductions in patient numbers or events can have a substantial impact on the research outcomes. Given the profusion of clinical trials investigating identical or similar treatments across different geographical and clinical contexts, one must also consider that the likelihood of the substantial numbers of false-positive and false-negative trials, emerging with the increasing overall number of trials, adds to public perceptions of uncertainty. Complicating this issue is the evolving nature of the pandemic, where baseline assumptions on control group risk factors used to develop sample size calculations are far more challenging than those in the case of well-documented diseases.The standard answer to address these challenges during nonpandemic settings is to rigorously assess each trial for statistical power and risk-of-bias and then pool the reported aggregated results using meta-analytic statistical approaches. This solution simply will not suffice for COVID-19. Even with random-effects meta-analysis models, it will be difficult to adjust for heterogeneity of different trials with aggregated reported data alone, especially given the absence of common data standards and outcome measures. Common data standards are a key feature of system interoperability and facilitate synthesis methodologies to be rapidly scaled, such as meta-analyses. To date, several groups have proposed structures and partnerships for data sharing in the context of COVID-19, some of which are integrated with prespecified statistical analysis methodologies ,11. GiveTo serve the public who are waiting for the medical research community to efficiently make medical discoveries, the COVID-19 pandemic has (arguably) mandated sharing IPD into a public health obligation. Although the International Committee of Journal Editors has previously discussed the importance of data sharing of clinical trials, this discussion has largely been limited to published clinical trials . The datSharing of IPD has historically proven to be challenging, as investigators and sponsors have held tight to their data for academic, regulatory, and commercial reasons. However, the health and economic consequences of the pandemic thus far signal a need to mandate data sharing, expedite systems to apportion credit for data sharing, and preserve commercial interests. The need to share and collaborate openly supersedes our personal career or organizational goals. This sentiment has been shared among the research community, and many organizations (such as the Wellcome trust ) have quThe International COVID-19 Data Alliance (ICODA) provides an example of recent improvements in data sharing within the context of a global pandemic ,18. ConvAs the processes for addressing personal privacy, data security, and data standardization have become sufficiently more sophisticated in recent years, barriers previously considered to be insurmountable have been minimized ,19. InveParticularly in the context of a pandemic, researchers, policymakers, and the general public are finding challenges in navigating the multitudes of data available daily. In tandem, high-profile instances of retractions owing to poor data screening  have ledWe hope that the COVID-19 pandemic is a historic turning point of a sharing culture in the medical research community. The need for rapid and robust clinical research for the discovery of effective and safe therapeutics and vaccines has never been higher. Strengthening our public health response to COVID-19 will require larger collated patient-level datasets to facilitate the scientific precision required for answers on COVID-19 medical interventions. As COVID-19 has forced reconsideration of policies, processes, and interests, this is the time to advance scientific cooperation and shift the clinical research enterprise toward a data-sharing culture that can maximize our response in the service of public health.


The novel coronavirus pneumonia COVID-19 is caused by the novel coronavirus SARS-CoV-2, which is highly contagious, has a long incubation period, and can be detected in patients' tears and conjunctival secretions. In this study, we describe our experience regarding the necessary protective measures that need to be taken during ophthalmic examination and treatment. The authors reviewed the clinical work arrangements during the epidemic situation at the Eye Hospital of Wenzhou Medical University in China and analyzed the prevention and control measures that were applied during the laser corneal refractive surgery process. The comprehensive protection protocol, which was established throughout the entire process, included both horizontal  and vertical  approach and was mainly focused on strengthening the protection against potential aerosol transmission that may occur during intraocular pressure measurements and laser ablation. The described and proposed protocol, along with the further guidelines followed by the medical personnel, proved to be efficacious and contributed significantly to the control of the COVID-19 outbreak and the protection of both the patients and the medical staff. As Wenzhou is a famous hometown of overseas Chinese, there are about 100,000 Chinese living in Italy. Therefore, we still cannot slacken to prevent and control the spread of the novel coronavirus in imported cases.In December 2019, a new type of coronavirus pneumonia  epidemic occurred in Wuhan, China. With the large number of people moving during the Spring Festival, the epidemic spread quickly to all parts of the country. About 180,000 people in Wenzhou, Zhejiang Province (China), were doing business and studying in Wuhan. Therefore, at the end of January, the number of cumulative confirmed cases in Wenzhou ranked in the top five nationwide. Since the first week of March, the epidemic situation in China has been effectively controlled, but the number of cases worldwide is increasing . The first imported case in Zhejiang Province occurred on 1st March. As of 24 : 00 on March 12, a total of 10 cases have been imported , previously known by the provisional name 2019-nCoV, is highly contagious, has a long incubation period, and can cause a severe respiratory disease known as coronavirus disease 2019 (COVID-19). Conjunctivitis has also been diagnosed in patients positive to SARS-CoV-2 , and SAREvery year before the Spring Festival, the laser corneal refractive surgery is at its peak. Our center carried out surgery until January 23, 2020 . On the same day, Zhejiang Province launched the first-level response to the major public health emergency. In accordance with the epidemic situation and the government's prevention and control instructions, combined with a series of hospital new regulations, the outpatient and surgical work was adjusted accordingly.It can be seen from After resuming work, the number of outpatient doctors and scheduled appointments was increased accordingly, but the number of patients remained limited . At the same time, the noon (12 : 00–13 : 30 pm) clinic was canceled, as ultraviolet disinfection of all examination rooms and consultation rooms was performed at that time. Regarding surgical arrangements, priority was given to patients requiring visual examinations, such as candidates of police and military academies, and civil servants while surgeries for other patients were postponed . In order to diversify the number of surgical patients, our center plans to carry out surgeries on Saturday and Sunday to reduce the average daily operation volume and the staff turnover in the operating room.During the epidemic, the center responded to the hospital's suggestion that all doctors open remote outpatient services to facilitate consultation for patients with moving/traveling problems and issued online prescriptions, which were delivered to the patients' homes after being approved by our hospital pharmacists. After resuming work, the safety education and online counseling services for the surgical patients are specific, and it is recommended that the patients should be checked at the nearest hospital branches to reduce the risk of cross-infection during travel.In order to avoid clustering, training sessions related to SARS-CoV-2 demonstrated protective measures and multiple ophthalmic academic meetings were held online during the epidemic.Although the domestic epidemic situation has been basically controlled, in order to prevent the transmission of SARS-CoV-2 in imported cases and asymptomatic infections, preventive and control measures should continue to be enforced until further notice. A number of medical institutions and committees have put forward recommendations for protective measures for ophthalmologists, disinfection methods of equipment, devices, and the environment, and patient management –10. BaseCOVID-19 is mainly caused by the invasion of SARS-CoV-2 in the respiratory tract mucosa. Spreading through respiratory droplets and close contact is the main route of transmission. SARS-CoV-2 can remain viable and infectious in aerosol form for at least 3 hours , and theCorneal thickness is one of the indispensable examinations before corneal refractive surgery. In the A-ultrasound method, the probe needs to contact the corneal surface. In order to avoid cross-infection, it is recommended to use noncontact optical measurement methods, including anterior segment optical coherence tomographic scanner ), corneal topography based on the Scheimpflug principle, optical biometer based on the principle of optical low coherence reflectometry (OLCR), etc.The direct ophthalmoscope examination is closer to the patient, and there is no isolation device between the doctor and the patient during the binocular indirect ophthalmoscope examination. The center prefers to use a slit lamp indirect ophthalmoscopy lens instead. Fundus photography, such as ultra-widefield ophthalmoscope, can also be used to help to diagnose myopic retinopathy such as peripheral retinal degeneration and holes if it is difficult to observe clearly with goggles.Surgery  may accelerate and exacerbate disease progression of COVID-19 in asymptomatic patients, and the risk factors for poor prognosis may be old age, comorbidities, surgical time, and difficulty of operation, so the possibility of the new coronavirus infection being excluded before elective surgery is very important .The combined test of serum amyloid A (SAA), C reactive protein (CRP), and blood routine can improve the effectiveness of diagnosis and differential diagnosis of bacterial and viral infections . EosinopAfter arriving at the center on the surgery day, the patient needed to fill out and sign the epidemiological questionnaire . The impPreoperative examinations of refractive error and conversations were conducted in the outpatient examination room.3) disinfection should be performed in the examination room and the consultation room twice a day (morning and noon) for 60 minutes each time [Stop using central air conditioning. Ultraviolet (1.5 W/mach time ; 500–100ach time , 23, oncach time , 24, andWith comprehensive prevention and control measures throughout our hospital, we took the lead in restoring the normal order of diagnosis and treatment in the country. In future times, epidemic prevention and control must be always done with due care, and we need to do our best in protecting patients and doctors in each possible way and carry out the clinical work of laser refractive surgery safely until the epidemic is over.