Due to the many restrictions imposed during the COVID-19 emergency, the normal clinical activities have been stopped abruptly in view of limiting the circulation of the virus. The extraordinary containment measures have had a dramatic impact on the undertaking and follow-up of ophthalmic outpatients.In order to guarantee proper monitoring and routine care, the Pediatric Ophthalmology equipe of Rovereto Hospital  supported by the Competence Center on Digital Health TrentinoSalute4.0, designed and implemented a digital platform, TreC Oculistica, enabling teleophthalmology. We report our innovative—albeit restricted—experience aiming at testing and maximizing the efficacy of remote ophthalmic and orthoptic visits.A multidisciplinary team created the TreC Oculistica platform and defined a teleophthalmology protocol. The system consists of a clinician web interface and a patient mobile application. Clinicians can prescribe outpatients with the App and some preliminary measurements to be self-collected before the televisit. The App conveys the clinician’s requests (i.e. measurements) and eases the share of the collected information in a secure digital environment, promoting a new health care workflow.Four clinicians took part in the testing phase  and recruited 37 patients (mostly pediatric) in 3 months. Thanks to a continuous feedback between the testing and the technical implementation, it has been possible to identify pros and cons of the implemented functionalities, considering possible improvements. Digital solutions such as TreC Oculistica advance the digitalization of the Italian health care system, promoting a structured and effective reorganization of the workload supported by digital systems.The study tested an innovative digital solution in the teleophthalmology context and represented the first experience within the Italian healthcare system. This solution opens up new possibilities and scenarios that can be effective not only during the pandemic, but also in the traditional management of public health services. In December 2019, the first cases of Coronavirus disease (COVID-19) emerged as a consequence of SARS-CoV-2 virus. COVID-19 is a contagious and potentially lethal respiratory infection that has resulted in a global pandemic with devastating consequences both for the economy and the healthcare systems worldwide , whilst Starting from March 2020, the American Academy of Ophthalmology (AAO) published updated recommendations for reducing the risk of SARS-CoV-2 transmission in clinics, including a questionnaire to identify patients with potential exposure to SARS-CoV-2, protocols for scheduling and visiting patients, environmental cleaning and disinfection recommendations, as well as guidelines about managing elective ophthalmic care, including and encouraging the use of telehealth services .Teleophthalmology enables clinicians to evaluate at a distance patients’ ocular diseases. In principle, this approach can have a positive impact as it can facilitate a more efficient and equitable distribution of often limited healthcare resources compared to the standard healthcare delivery. In particular, during the outbreak of COVID-19, telemedicine allowed triaging patients even before their access to the medical facilities, avoided unnecessary visits by monitoring and performing remote visits, and thus reduced infection risks in the healthcare setting . InnovatOphthalmology can rely on several techniques aimed at screening, following up and treating patients with different ocular diseases, techniques that can be performed also at a distance, typically by trained staff. In this context, smartphones play a pivotal role in the teleophthalmology field : they alIn recent years, far before the COVID-19 pandemic, the number of ophthalmic mobile applications increased significantly. The technological development contributed in changing the traditional patient-doctor relationship by introducing remote-testing methods and encouraging patients to monitor their health conditions and supporting clinicians in the assessment phase. Nevertheless, before the COVID-19 emergency, these innovations did not affect all the ophthalmic subspecialties equally, and were not diffusely adopted within traditional healthcare systems . The panTreC Oculistica. The core pillar of this innovative organizational model lies in the new role that is assigned to the patient and the new doctor-patient relationship that is promoted through this initiative. Thanks to the technological assets and tools available, a hybrid model is adopted, where patient-collected and provider-collected pieces of information are used together to support healthcare staff in taking informed decisions and monitoring the eyesight conditions of outpatients.In this paper we describe an innovative and, to the best of our knowledge, unique experience conducted in 2020 in the Province of Trento . The group of pediatric ophthalmology of Rovereto Hospital, together with the multidisciplinary group of the Competence Center on Digital Health TrentinoSalute4.0, designed and implemented an organizational protocol for managing outpatients, follow-ups and screenings. The protocol was enabled by a new technological system purposely designed to promote teleophthalmology during the COVID-19 outbreak. The system consists of a clinical digital platform and a smartphone-based App, We will provide a description of the system and its functioning, emphasizing the organizational protocol adopted to test the technological asset. We will then present the experience performed with a small sample of patients. Finally, we will discuss the overall initiative, pointing at pitfalls we have encountered and at lessons learned.Global mobile market report shows that 60.8% of Italian citizens actively use a smartphone, and that this percentage is likely to increase through the years [The system, TreC Oculistica, was named by merging the patient’s medical record digital platform used in the Trentino Italian Region (TreC)  and the he years .To develop TreC Oculistica system, we adopted a structured and sequential approach  aimed atThe initiative was approved by the Provincial Healthcare Service in line with the healthcare strategy promoted by the Province of Trento as political stakeholder. According to Italian legislation, neither approval from the ethics committee nor informed consent from the participants is required in case both scope and purpose of data processing are part of the provision of healthcare service. Only MD and clinical staff had access to patient’s data for clinical purposes only. Patient’s data included in the manuscript were obtained in a fully anonymized and de-identified manner.In the very first months of the outbreak, the Ophthalmic Unit of Rovereto Hospital was forced to suspend all the outpatient’s services, limiting the clinic access to emergency visits only. This abrupt interruption led to bewilderment among patients and to logistic difficulties in providing outpatients healthcare, due to (i) the reduced visits space, (ii) the increased sanitation procedures and (iii) the need for proper social distancing. Within a few weeks, from March to April 2020, the number of non-delivered health care services increased dramatically, exceeding 2000 units.To deal with this unprecedented situation, affecting not only the Operative Unit of Ophthalmology but most of the healthcare branches, the Autonomous Province of Trento (PAT) and the Provincial Healthcare Service (APSS) applied specific actions, namely:Updating the nomenclator of outpatient specialist assistance services by formally including telemedicine among the offered services .Adapting the national guidelines to the specific regional context, indicating and clarifying the procedure for healthcare staff conducting and accounting a televisit. During the pandemic, all the telemedicine services have been provided on a co-pay-exempt basis, promoting equity and accessibility to telemedicine healthcare services.Even though ophthalmology strongly relies on instrumental examinations, there are yet some clinical measurements that can be acquired without the need of any professional equipment, allowing the evaluations of a relevant number of eyesight conditions by means of patient-collected information. As reported in the introduction, the ability to provide eye care services from a distance is already a standard in some countries . Looking at those good practices, we tested an innovative approach to telemedicine. Easy to use printable materials and digital mobile applications were purposely selected by the healthcare staff (see paragraph 1.5) and patients were invited to actively contribute to the evaluation of their eyesight condition by providing healthcare staff with some specific parameters collected autonomously using the suggested materials (patient-collected information).The protocol adopted in the first months of pandemic consisted in contacting the already booked-for-a-visit patient telephonically, offering the possibility to undergo a remote visit. Instructions and materials were then sent by email seven to ten days before the scheduled televisit together with another email with the link to the video-call platform (i.e.Google Meet). Patient’s measurements were collected via email and evaluated before the televisit. After the televisit, the healthcare practitioner produced a medical report.This initial organization, adopted at the very peak of the pandemic, was long and complex, requiring a considerable amount of time and energy for the healthcare staff to collect and organize the material sent and received before the televisit. Moreover, the digital platform used to exchange sensible clinical information and to perform televisit could not guarantee the appropriate privacy and security levels in data sharing. Thanks to the support of the Competence Center on Digital Health TrentinoSalute4.0, a multidisciplinary group including medical doctors, project managers, informatics and technologists, designed and implemented the technological solution for teleophthalmology TreC Oculistica, simplifying the organization of the activity both for healthcare practitioners and for patients.In the following paragraphs we report the stages that led to the creation of the system.The first task of the working group was to define the requirements of the system.As stated before, the necessity was to simplify the steps to be conducted prior to the televisit  by providing patients with appropriate indications and materials, and by organizing the reception of preliminary measurements required to avoid missing data. This led the working group to design (i) an easy-to-use mobile App for patients and (ii) a dedicated web interface for healthcare staff.Patient’s App main functionalities:Video-call: a secure and encrypted channel that allows the safe execution of the televisit without relying on third party services;Chat: an asynchronous encrypted communication channel to be used in the period before the visit, to exchange additional information with the clinician and to clarify possible doubts;Televisit preparation area: a section purposely organized to guide patients in getting ready for the televisit. Patients can find information about the measurements they are asked to acquire autonomously and in which order is needed to insert the collected data;Tutorials area: a list of detailed instructions on how to perform each requested measurement;Measurements archive: a section where data inserted for previous televisit appointments are stored;Complementarily, the functionalities identified for the clinical web interface are:Patient’s profile and App activation and prescription function: clinicians have to activate patients’ profiles in the clinician web interface in order to be able to prescribe the use of the App, allowing patients to access the App functionalities.Video-call: that allows programming and executing televisits;Chat: that the clinician can activate or deactivate depending on the need, through which providing assistance during the collection of measurements;Checklist of measurements: a list of all the materials and measurements integrated in the TreC Oculistica App that can be provided to patients. The measurements selection can be personalized patient by patient, selecting those more appropriate from the checklist;Dashboard: a dedicated area for each patient where all the information shared with and collected from the patient through time are grouped and organized and can be consulted before the televisit. Through the dashboard, the clinician can access the list of all the televisits performed with a specific patient and compare the data collected with those of previous televisits.Cartella Clinica del Cittadino, citizen’s clinical record). The TreC digital platform represents the citizen frontend to the local healthcare system and healthcare services. With the use of digital identity credentials (e.g. SPID identity), it can be accessed both via computers and via smartphones, allowing citizens to consult their Electronic Health Record, to manage their Personal Health Record and to access different public healthcare services  .The TreC platform incorporates various services through its middleware, that allow the ecosystem to be flexibly integrated with different devices, services and functionalities. Some basic services such as authentication and access control are implemented in order to allow patients to safely use the App and share information in a controlled way. Through the middleware, the patient’s App and the clinical web dashboard are connected and able to communicate . The correct functioning and the security of the technological infrastructure of TreC is constantly maintained and updated.The TreC ecosystem also allows performing small tests before implementing a new service in the main citizen frontend. TreC Oculistica has been tested within a dedicated pre-production digital environment.The TreC Oculistica patient’s App, available for both Android and iOS, can be accessed only after a healthcare practitioner prescription. The use of the app is legitimate within the boundaries of a doctor-patient relationship and its use is regulated by clinical purposes and within the legal frame imposed by the GDPR regulation. When downloading the App, the patient has to accept the Terms of Service and Privacy Policy and to complete the registration. Even though this initiative does not require participants’ informed consent, as it is a specific—albeit innovative—component of the standard healthcare service provision, we asked and collected a digital “consent for using the App” from each patient/caregiver. Then, only after his/her clinician prescribed the use of the App, he/she is allowed to access the functionalities of the App . The AppMeasurements’ tutorials: in this area the patient can find one instruction file for each possible prescriptible measurement. Instructions are also provided for some exercises that will be performed real-time under the supervision of the clinician during the televisit.My televisits area.My televisits: when a new televisit appointment is scheduled patients receive a notification on their smartphone. Patients can visualize the appointment and answer the clinician video call in the televisit preparation area, patients can find the list of the measurements required by the clinician. Each measurement is marked with a red cross until the data is inserted, then the red cross changes into a green tick , and access the helpdesk contacts, information on the App, and the Terms of Service.The clinical dashboard is a web-based interface that allows ophthalmologists and orthoptists to record patients, prescribe the use of the App, schedule televisits and recommend preliminary measurements patients can collect at home, and to display data and measurements collected from the platform (i.e. patient App). The dashboard is accessible with valid credentials only to those healthcare practitioners that have been authorized by the platform administrator. The dashboard is integrated with the provincial health registry and allows to visualize the main personal data of each citizen in charge of the provincial healthcare organization .Each enrolled patient has a dedicated clinical area that contains all the information the patient decides to share with the clinician. The measurements and the data related to a specific televisit, can be visualized in a structured matrix  avoidingThe majority of ophthalmic visits, both first-visits and follow-up of pediatric or adult patients, require evaluating visual and visuo-motor functions, such as: visual acuity, eye motility, macular function, visual field and color vision . These eThe applications that have been identified within the TreC Oculistica App were selected considering the following criteria: ophthalmology-related medical applications, high sensitivity, ease of use/user friendliness, availability and free download.The other materials loaded on the TreC Oculistica App were selected among those commonly used in the medical practice, where the visualization on printed paper or on a screen could be standardized based on different printers and digital devices.To support patients and caregivers in the acquisition of measurements, we provided written tutorials illustrating the correct execution of each single measurement.Visual Acuity Charts. This App displays optically precise optotypes of eye charts to accurately measure distant visual acuity [Mobile applications. l acuity –25.Supported OS: Android and iOSSelected optotypes: Snellen for adults and Tumbling E for childrenTest distance: 3 metersSuggested notation: decimalTest modes: manual or auto play9Gaze. The App allows the creation of composite images aimed at monitoring eye motility and strabismus in the nine cardinal positions of gaze [ of gaze –28.Supported OS: Android and iOSeyeTilt. Digital goniometer aimed at measuring head tilts and turns using the mobile’s camera.Supported OS: Android and iOSFeatures: on-screen guide for placement of eyes and/or noseMD EyeCare. The App performs the Red Reflex test instrumental in detecting opacities in the visual axis, such as a cataract or corneal abnormality, as well as abnormalities in the posterior segment, such as retinoblastoma or retinal detachment. It can also detect subtle differences in the red reflex between the eyes, indicating the presence of strabismus or refractive errors [e errors .Supported OS: iOSColorblind Eye Exam Test (iOS) and ColorBlind test (Android). Color blindness test aimed at assessing color deficiency, especially in the red and green tones.HOTV, ABCD-Vision . paper-based HOTV crowding bar visual acuity test adapted to be self-administered remotely by patients [patients , 30.Test distance: 3 metersLEA Symbols, LEA-Test Ltd. Visual acuity testing chart for pre-schooled children evaluation. The optotype is adherent to the World Health Organization (WHO) and the National Academy of Sciences Committee on Vision recommendations about optotype choice and arrangement on visual acuity testing charts [g charts , 32.Test distance: 3 metersSnellen chart. Snellen visual acuity testing chart for the evaluation of both adults and children [children .Test distance: 3 metersAmsler grid. A reticle with vertical and horizontal lines used to detect vision deficits resulting from macula (e.g. macular degeneration) or optic nerve (e.g. glaucoma) damages [ damages .Cover Test. Instructions showing how to perform the cover test  during the televisit. The test allows the detection of different forms of strabismus observing refixation movements.Hidden Image Stereograms. Instructions and web-links were provided to investigate 3D vision by means of computer-generated Single Image Random Dot Stereograms (S.I.R.D.S) [I.R.D.S) .The process adopted to recruit each patient consisted in telephonically contacting the caregiver/patient, explaining the new system, asking him/her to download the App TreC Oculistica, plan a day for the televisit and enrolling the patient into the clinical dashboard by prescribing measurements and the televisit appointment.Some days before the scheduled appointment, the caregiver/patient could ask for assistance in completing the measurements process using the chat, load the data collected and get ready for the televisit by reading the informative material. On the appointed day and time, the healthcare practitioner conducts the televisit. After the remote visit, the clinician would write a medical report and account for the televisit within the hospital IT system.We identified three different scenarios that could be triggered by the televisit:The televisit and the information collected are informative enough to state the patient’s sight condition and no additional in-presence evaluations are needed. The next follow-up visit is normally booked.The televisit highlights the need for additional instrumental analysis. The patient can perform the examination in a local facility and then share the results with the hospital healthcare staff through the App. A new televisit is performed and the patient’s evaluation is completed.The televisit shows the need for a face-to-face examination. An appointment is booked and the patient is visited in the clinic.Four clinicians  were actively involved in testing the system. Each healthcare staff underwent an individual training session in order to familiarize with the system and be autonomous in its usage. Additionally, two manuals regarding the clinician web interface and the patient’s mobile App were provided for further support. A helpdesk service, available both for patients and clinicians, was activated for technical support and specific operative needs. After the training session, healthcare professionals were given access to the clinical web interface by the platform administrator.In the first stage of implementation (approx. three months), 54 patients were proposed a televisit, 37 patients   agreed tThe televisits were performed both with residents in the Province of Trento (N = 35) and with patients living outside the Region (N = 2). Aiming at testing mainly the use of the platform and of telemedicine within the Ophthalmic Unit, a conservative patients selection strategy was adopted discarding those with a complex clinical picture. As a result, none of the televisited patients needed to access an in-person visit. Patients involved in the testing phase reported to be overall satisfied.In this paper we described the genesis and the evolution of an innovative approach to teleophthalmology that took place during the COVID-19 outbreak in the Province of Trento. To our best knowledge this is the first structured attempt in the Italian healthcare system to design and implement a technological solution for teleophthalmology to cope with the new challenges the pandemic highlighted. The COVID-19 unprecedent circumstances have encouraged the adoption of telemedicine in different medical fields exploring different approaches. Similarly to the approach adopted in the present study, in the neurology field the possibility to perform some evaluation at a distance has been tested. With the use of mobile phone’s applications, wearable devices, e.g. accelerometers, or the remote administration of clinical tests, clinicians were able to successfully assess patient’s condition reducing the hospitalization and improving patients’ quality of life –39.The sThe introduction of a new digital solution can be extremely challenging. In the following paragraphs we will provide an overview of both pitfalls and limitations encountered, lessons learnt and future steps.Even if designed to be intuitive and user friendly, technology is not accessible to everybody. In a recent paper, Scanzera et al.  highlighTogether with all the above-mentioned considerations, we have also found that language might be a limitation in the adoption of a digital solution. The TreC Oculistica interface is in Italian; nevertheless, in a growing multicultural society, digital technologies should be accessible also to non-native speakers. This of course has some other implications, such as increasing costs in developing digital solutions and time constraints in the release of the system.Moreover, some people are more prone than others in trusting new technologies . There iThe testing of TreC Oculistica has been extremely useful in understanding limitations and ameliorations to implement in future releases.One of the first considerations that emerged was that the evaluation of some patients at a distance would have been easier if patients could rely on a bigger screen. A web version of the App would respond to this need allowing patients to undergo ophthalmic televisits more comfortably. Nevertheless, it has to be considered that some smartphones are equipped with high resolution webcams that convey a better image resolution compared to standard PC webcams. The acceptable balance between image resolution and screen size should be established for each televisit according to the available devices.Moreover, in the material selection we tried to select free-of-charge medical mobile applications, as we did not want this initiative to require additional economical effort from patients. However, it is possible that some of these applications will not be free-of-charge in the future. Currently, the Ophthalmic Unit is considering alternative materials  that could substitute the use of paid Apps. We have also found that visual instructions , instead of written instructions, would be much more effective and enjoyable for App users. We are currently realizing some video tutorials to upload on the App in the Measurement’s tutorial section.The integration of the TreC Oculistica system with the hospital IT system  would also optimize and encourage the use of the system, as clinicians could complete administrative  and clinical (e.g. televisit) procedures accessing a single interface.In addition, in few areas of the Region the internet connection quality is not optimal, causing difficulties in conducting televisits. Overall, even if on a small scale, this test is useful in identifying practical obstacles that, if not address, could interfere with the success of a virtuous initiative.As argued by Saleem et al. , there iWhen considering the transmission of sensible data, privacy issues and data management are extremely important . The COVDespite the tragic outbreak period, the COVID-19 emergency provided the public health sector with the opportunity to re-think the health organization and paved the way for testing and implementing new digital services. If, as reported by Gioia and Salducci , in 2019In the past few years, the Province of Trento  implemented different digital solutions to improve the quality of services provided by the local healthcare –53. In tOverall, the first attempt in approaching teleophthalmology has been positive. The co-designed system has been well accepted by patients and clinicians as it is easy to use and intuitive. It represented a good help in monitoring and supporting outpatients despite social-distancing limitations. Telemedicine, when possible, is convenient not only for the healthcare system but also for patients, that can avoid transportations to reach central hospitals, saving time and money (i.e. gas and parking) . We mainImproving patients’ satisfaction toward a service is not always enough to amend a structural organization. Evaluating the economic impact of digital services is necessary to understand the sustainability of an innovation. New evidence is produced about the economic impact of digital innovations, showing cost savings for the healthcare system . The intSmartphone applications are an interesting tool in the teleophthalmology scenario, nevertheless how they could be used in the clinical practice is an open question . Should The process described herein represents a valuable example of health digitalization during COVID-19 outbreak. Even if this experience has been implemented on a limited number of patients (so far), the proficient contribution of the group of pediatric ophthalmologists and orthoptists has led to a promising protocol which is now ready for scale up.Despite the fact that the COVID-19 pandemic sadly represented the incentive, arose by a necessity, to walk out of the comfort zone of known clinical procedures, this context has promoted the adoption of a different and challenging approach in teleophthalmology, which proved to be potentially solid.


Active inference is a multiscale approach to behavioral modeling that is being applied across settings in theoretical biology and ethology. The ant colony is a classic case system in the function of distributed systems in terms of stigmergic decision-making and information sharing. Here we specify and simulate a Markov decision process (MDP) model for ant colony foraging. We investigate a well-known paradigm from laboratory ant colony behavioral experiments, the alternating T-maze paradigm, to illustrate the ability of the model to recover basic colony phenomena such as trail formation after food location discovery. We conclude by outlining how the active inference ant colony foraging behavioral model can be extended and situated within a nested multiscale framework and systems approaches to biology more generally.In this paper, we introduce an active inference model of ant colony foraging behavior, and implement the model in a series of  In our model, we focus on the The active inference framework naturally lends itself to modeling behavior of different systems across scales. Generally, what changes across models available in the literature are agent action affordances , the semantics of the prior beliefs , and the hyper parameterization . From the point of view of the dynamics  all active inference models are the same. Here we present the first Active Inference type model of stigmergy, and the first Active Inference model focusing on insect behavior. Our simulation adapts the inferential architecture developed by Constant and colleagues . Thus unlike custom ant-specific models coded in various languages, having an abstraction for ant colony function based on active inference agents can be transposed into different contexts. The biological reality of ant colony foragers is that they have evolved various features such as learning, neuromodulation of sensitivity to pheromones, the ability to leave multi-component pheromone trails, the ability to maintain a given colony size, regulate colony foraging, etc. Even though the proof of principle on offer does not model these features explicitly, all these features could be explored under a future active inference model. We come back to this point in the discussion section.In the model presented here, foraging ants move around in a defined area that includes a nest location and a food resource location. The forager actively infers a single sensory (gustatory) outcome: an idealized attractant trail pheromone .The T-maze choice test and related Y-maze paradigm , it begins depositing trail pheromone as it navigates back to the nest entrance. This usage of attractive trail pheromone by incoming successful foragers is inspired by the ecological context of foraging in the The basic challenge faced by the ants in our simulation is to locate the food resource patch, which alternates every 500 time steps in the simulation  over 2,000 steps. The colony must rediscover the food location (on the other side of the T-maze) when its location changes. We add a decay parameter to the attractant trail pheromone, such that at each time step, the density of the pheromone at the visited locations decays with a small probability (0.01% in the simulations presented here). Biologically, this can be viewed as the gradual decay or evaporation of lipid pheromones (which range from volatile to wax-like). Informationally, this decay rate can be thoughts of an environmental perturbation or drift that counteracts the reinforcing effect of stigmergic convergence.In our simulation, after discovering the food, inbound foragers begin a random walk that is biased toward higher concentrations of trail pheromone and also biased toward the direction of the nest entrance. The biological plausibility of this inbound turn is well-supported by a variety of mechanisms used in ants to navigate home from foraging trips, including the path integration of steps , however with the provided code one can adjust this to any value. We performed simulations of 2,000 time steps , meaning that each ant carried out 2,000 steps of action and inference. We considered two summary measures as colony-level phenotypes.First a colony foraging performance metric which is simply the number of round trips between nest and food location over the 2,000 time steps. The more round trips that are completed per unit time, the better task performance is, in the sense that successful foraging was accomplished more often. As the location of the food resources shifts several times during the simulation , successful colony foraging here represents an ability to both discover and exploit resources that are dynamically changing through time.Second a swarm coherence metric was calculated as a distance measure among ants at each time step as:dis is the Euclidean distance between two ants, i.e., xn and yn denoting the x and y position of ant n. The goal of this simple swarm distance metric was to capture some possible signatures of collective phase transitions .The distance coefficient quantifies the average distance between all ants at any given time point, where Active inference is a Bayesian theory of behavior that accounts for perception, learning, decision-making, and the selection of contextually appropriate actions, which are all cast as a form of approximate Bayesian  inference. In this framework, perception is modeled as the formation of posterior state estimates, which are arrived at by combining priors and likelihoods, that is, the prior beliefs had by an agent about the base rate of occurrence of states and the likelihood of making this or that observation given this or that states; learning is cast as the process of updating of priors, likelihoods, and other model parameters; and decision-making and action are cast as processes that compare the evidence for various models about future states and observations under possible courses of action see .A, which specifies the probability of observations given hiddens states; (ii) the transition probability matrix, B, which harnesses the probability of state transitions, i.e., the probability of transitioning from one state to the next, given some action. C is a preference parameter that foragers have for denser pheromone traces, i.e., the agent prefers to move in the direction of the locally-densest pheromone trail. The prior over initial states after each cycle of inference is denoted D. Finally, prior preferences for data C enter into the computation of the expected free-energy, G, which is a vector of values that corresponds to the free energy expected under a given course of action or policy through time .$17 The simulation uses a Markov decision process (MDP) formulation of active inference; for details, see the code and  in the model and represents the agent's beliefs about the current state of the world. The generative model describes an agent's “model” of the world, and specifies a mapping from hidden states to observations. Variational inference then looks to invert this mapping and recover the mapping from observations to hidden states see ] rather o) of the ant are the intensity of pheromone, ranging from 1 to 10. This pheromone intensity reflects the hidden underlying actual pheromone density at each location (s). The likelihood parameter (“A”) parameter maps all possible sensory outcomes (10) to all accessible locations at each given time. The state transition probabilities are coded as the transition parameters , which encodes all possible transitions among all possible states, conditioned on policies . Effectively, this means that there are nine transitions matrices, for nine possible policies that allow the ant to go in all directions. The likelihood and the transitions are fixed in all simulations. We use this generative model and an initial state distribution D to generate sequences of potential future outcomes and hidden states and potential 1-time step policies (sequences of action). Policies are scored in terms of their expected free energy (denoted G). The expected free energy of each available policy is evaluated (here the accessible cells), and the policy with the least expected free energy is selected by the agent. Preferences are encoded in a vector C that specifies a desired probability distribution over outcomes. To generate the different phenotypes of The generative model of each ant consists of a single hierarchical level . The hidNote that the model on offer differs from some active inference MDP models in that the agent—here, the ant nestmate—does not have an internal representation of the complete structure of the environment . Here, the ant can only represent the pheromone gradient which surrounds it locally and instantaneously. Specifically in our grid automata model, the forager can detect one location around its current location in the map, in each direction . These local pheromone deposits make up the hidden states. For real ant foragers, the perception horizon for chemosensation is limited by the reach of their antennae . Additionally the ant can only take steps in their immediate direction (cannot teleport).via the reallocation matrix.To limit the perception and inference horizon of the ant in a biologically realistic way, we added to the standard active inference methods a recently-developed “reallocation matrix” see the . To ensuTo summarize the computational activity of each forager at each timestep, pseudocode is provided here (see Code for full details). The active inference model as implemented here does not presuppose or imply any specific neurocognitive architecture for any specific ant species. At each timestep of the simulation, the agent:Senses environment Optimizes beliefs with regard to Variational Free Energy Agent performs action (movement) and updates the environment Our unimodal (gustatory) model here does not take advantage of forager visual capacity or interactions, and only is based upon the stigmergic principle of pheromone deposition. Future models could include ant bodily state, development, memory, and intermodal integration. The reallocation matrix allows us to remap the likelihood matrix of the generative model of the ant based on its movement in the environment (it is a movement policy matrix). The purpose of the reallocation matrix here is to allow such a remapping of the likelihood of the ant, which is just a 3x3 portion of the reallocation matrix relative to where the ant is at a given time step. In other words, this reallocation matrix is what transforms the global computational representation of the foraging arena, into a locally-accessible space around each ant, guaranteeing that the relevant information used by each ant is really only local.Stochasticity in decision-making at the nestmate and colony level may facilitate adaptive behavior in ants . Colony-level phenotypes are summary measurements of emergent properties in that these phenotypes do not apply to separate nestmates  in such a characteristic summary distance metric. Swarm coherence metrics might also be defined not in terms of inter-agent distance, but rather the correlation, mutual information, or degree of stereotypy among trajectories.Here we have presented an active inference framework to consider some aspects of the multiscale and emergent dynamics of an ant colony. Active inference may be informative in the study of ant colonies at three distinct temporal scales: nestmate behavior (emergent among tissues of a nestmate and interactions with the biotic/abiotic environment), colony development (emergent among nestmates and their interactions with the niche), and the evolution of populations (emergent among colonies within an ecology). In this work, we have focused on the connection between the first two levels of analysis, specifically focusing on the case of stigmergic colony foraging, using a modification of previous active inference computational implementations. We utilized a partially Markov decision making process model based upon previous work, with several ant-specific modifications Methods, .We found that colonies of active inference foragers were able to discover and stigmergically exploit food resources in a simple T-maze . ForagerThe first scale of analysis to consider in the ant colony case is that of perception, learning, and decision-making under active inference for ant nestmates . This is the scale that we explored here in this series of simulations. We limited our simulation work to perception and a rudimentary form of hyperlocal decision-making . In so doing, we did not take advantage of the full scope of active inference. Active inference can model phenomena such as curiosity, novelty, affect, and valence biases in terms of how they arise from estimates of world states and variabilities , and the pheromone trail is considered as a semiotic cue that guides the forager toward the target. Under the active inference framework, the reward (preferred observation) plays a more semiotic role (in engaging a switch in the foragers behavior from outward to inward bound) while the pheromone trail density plays the role of a reward . In terms of observations about the pheromone trail, and the target resource is a cue that engages a switch in course of action . Acting as a function of reward, here, just means selecting the action that provides the most evidence that the agent is generating preferred observations [for details see Friston et al.  and CostThe second level of dynamics here, not addressed in our simulation, is the learning of nestmates and development of colonies. The colony as an organism itself has developmental phases that go beyond the timescale of behavior Wheeler, . Such coimplicitly by each ant as they each forage alone, together as a colony, leaving cues that nestmates can use adaptively. In active inference terms, the ants are endowed only with an extended generative model  may contribute to variation among colonies in behavioral outcomes . We did not, for instance, manipulate several key parameters of the model that might have influenced the number of round trips between the food location patch and the nest. Also of note is that eusocial insect foragers are able to communicate information to each other regarding foraging resources through interactions and chemical stigmergy. This means that foragers are able to distinguish and integrate various internal and external factors related to bodily physiology  and recover some of the classic findings of laboratory and field behavioral observations in insects. The ant colony has long been an inspiration for agent based models and robotics, as well as computational algorithms (Rossi et al., https://github.com/alec-tschantz/ants.Publicly available datasets were analyzed in this study. This data can be found at: DF and AC wrote the first draft, AT and AC designed the simulation, and MJDR and KF made substantial additions to 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. The handling Editor declared a past co-authorship with one of the authors DF.


Medication-related osteonecrosis of the jaw (MRONJ) frequently affects patients after treatments with bisphosphonates or denosumab, especially with high doses in patients with bone osteoporosis, neoplastic metastases, or possibly anti-angiogenic treatment for cancer. The aim of this article was to show a new treatment planning for stage 2 and stage 3 MRONJ using platelet-rich fibrin (PRF) at the surgical field to enhance healing in association with a new epi-mucosal fixation technique to prevent or treat mandibular fracture. Two cases were treated by epi-mucosa fixation and autologous PRF use for prevention of mandibular fracture risks related to necrotic bone resection or a narrow fracture reduction. Both cases were successfully treated by this new technique of epi-mucosa fixation combined with autologous PRF and achieved good results and good quality of life. Ability to wear prosthesis with good mastication in the absence of side effect such as infection, plate and screw mobilization, pain, and other disabilities or extension of necrosis was reported. After surgical removal of necrotic bone, no infection was detected without any extension of the necrosis. Medication-related osteonecrosis of the jaw (MRONJ) is an adverse effect of treatment with denosumab or bisphosphonates  or possibly anti-angiogenic treatment for cancer. Preventive measures in recent years have reduced the risk of MRONJ in patients with bone metastases due to cancer, particularly by avoiding trauma or invasive therapies and preventing or treating dental infections before and during therapy with denosumab or bisphosphonate. If MRONJ is developed, conservative medical treatment  can provide improvement, but the achievement of mucosal closure remains challenging. Symptoms management and mucosal healing are the ultimate goals of therapy but, after the failure of conservative treatment, a surgical approach may be beneficial. Overall, a multidisciplinary and pragmatic approach to MRONJ should be adopted, giving priority to quality of life and management of the patient’s malignant skeletal disease.Stage 1—In stage 1 the upper or lower jaw bone is exposed in the absence of symptoms; in this stage the treatment is conservative: Improve oral hygiene by actively treating dental and periodontal diseases; rinses with topical antibiotic. Surgical treatment is considered only to remove necrotic bone.Stage 2—In this stage we have exposed bone associated with pain and inflammation, swelling, or infection of adjacent soft-tissue. Treatment is like that in stage 1 with the addition of systemic antibiotic to treat any infection and symptomatic therapy.Stage 3—In the third stage we have same staging criteria of stage 2 plus at least one of these: Pathological fracture, extra-oral or oroantral fistula and radiographic evidence of osteolysis extending to inferior border of mandible or floor of maxillary sinus. Treatment is like that in stage 2 with administration of systemic antibiotics. However, in extended cases we consider a surgical resection of the jaw and reconstruction.The stage of MRONJ at presentation is prognostic for the success of conservative  treatment, with only a very low likelihood of healing in patients who have higher stages of the disease . NotwithAlthough osteonecrosis of the jaw (ONJ) is typically diagnosed clinically, the use of orthopantomography, CT, and/or MRI are necessary. Another problem that should be considered in the staging of MRONJ is the lack of dimensional criteria; currently the disease affecting an entire quadrant can be staged in the same way as a lesion with a diameter of less than 1 cm, even if the probability of favorable outcome can be totally different.Use of corticosteroids;Presence of diseases or concomitant conditions ;Poor oral hygiene and smoking .Clinical observation has shown an association between the onset of MRONJ and dental extractions and infection, although the underlying mechanism of how these events lead to osteonecrosis remains poorly understood, and high-quality evidence is required. Other factors that negatively influence MRONJ have been reported in the literature as being associated with its accelerated development and an increase in the severity of the condition, but their causal association is not clear ,2. TheseAAOMS emphasizes that priority should be given to cancer treatment for patients with cancer and bone metastases at risk of developing MRONJ . We needA combination of preventive measures taken both before and during treatment with denosumab or bisphosphonates can significantly reduce the risk of MRONJ1 .The aim of the work is to show new procedure and new planning for second-third stadium (heavy stadium) for medication-related osteonecrosis of the jaw (MRONJ), which is most conservative as possible and also effective in preventing mandibular fracture in risky cases or in a fractured affected case. In these cases, because of published evidence that osteonecrosis of the jaw is related to surgical aggressive therapies, there is a contradiction between etiology of the MRONJ and the most effective treatment with surgical procedure. To solve this problem, we developed this new therapeutic planning using an epi-mucosal fixation technique from our experience in orthognathic and orthopedic maxillofacial surgery. In this way, close reduction of the fracture and close stabilization of the fracture was achieved, minimizing surgical approach and surgical effect impact on the affected bone area. Stabilization of the affected bone segment can be achieved by fixing the plate using self-locking screws in the affected bone segment through the epi-mucosal technique without any need for periosteal elevation or mucosa incision. Autologous platelet-rich fibrin (PRF) was used, combined with fixation to improve the healing abilities of the bone segment and the mucosa after bone sequestrum removal and shaving of the sharp bone borders of the affected area.Many studies have shown that PRF is a healing biomaterial with great potential. PRF stimulates bone and soft tissue regeneration, without inflammatory reactions, which can be used alone or in combination with bone grafts, promoting hemostasis, bone growth, and maturation ,4. PRF cThe aim of this study was to develop a protocol for the treatment of stage 2 and stage 3 MRONJ with extensive bone necrosis causing segment fracture or high-risks for fracture. We combined the advantages of using PRF with the advantages of surgical removal of the necrotic bone and stabilization of the pathologic fracture of the necrotic bone segment that prevents fracture risks of the affected segments after resections or sequestrectomy. To avoid periosteum elevation during rigid bone fixation, we adopted a new technique for rigid fixation: The epi-mucosal fixation. This technique was already validated and published for jaws reducible fractures: It was the first time it was adopted in MRONJ cases, hence the scientific relevance. The study follows the rules of our Ethical Committee.Two cases are described in this study.Both cases were examined by X ray panoramic and CT scan pre-operatively and in the short post operatively time. The first case was a 72-years-old woman of Caucasian origin, who was referred to the maxillo-facial unit of the University Hospital of Salerno complaining of pain in the region of the left side of the mandible. The patient had received a mastectomy in 2013 in another hospital for a primitive breast cancer. Since 2014 she was treated with denosumab for bone metastases secondary to a primitive cancer.Surgery was performed under general anesthesia. We proceeded to the superficial removal of damaged tissues in the site of the osteonecrosis outbreak to avoid extension of the necrosis and to enhance healing abilities. We eliminated all the necrotic tissue, saving healthy tissue at the excision border to preserve as much as possible mandibular contour aesthetic and function. To stabilize the bone segment, an epi-mucosal fixation was performed using SMART Lock screws and plates without elevation of the mucoperiosteal flap, therefore avoiding any new bone necrosis risk C.The self-locking screws and plate were inserted before the necrotic bone area resection or sequestrectomy by epi-mucosa plate modelling, positioning and fixing with trans mucosa screw insertion. No need for mucosa incision or periosteal elevation was required at this step of the procedure; the self-locking screws and plate acted as a rigid external fixation system.®  EBA 20 of centrifuge with a fixed eight-point angular rotor was used for the procedure. Centrifugation time changed according to the consistency required for the PRF; the longer the centrifugation time, the harder the consistency of the PRF sample. After centrifugation, a PRF from the center of the tube was obtained; the centrifuged red blood cells at the bottom and the acellular plasma at the top were discarded. The PRF was inserted directly into the osteotomy slot after sequestrectomy and sharp bone trimming. Several studies have assessed the efficacy of PRF in intra-osseous and mandibular grade 2 MRONJ defects and found a positive clinical and radiographic outcome [Next, we proceeded to the preparation of autologous PRF to be used as a regenerating and healing stimulating material by collecting 40 mL of peripheral blood from the patient at the time of surgery. Blood samples were collected in 8.5 mL tubes without any anticoagulant and immediately centrifuged at 2700 rpm for 12 min to prevent activation of the coagulation cascades. A model HettichA vicryl polyglactin  absorbable suture was used to close the flap.The postoperative course was without complications. Postoperative therapy comprised oral hygiene instructions, rinsing with 0.2% chlorhexidine solutions twice a day, and an evening application of 0.2% chlorhexidine gel upon the sutured incision lines, as well as the administration of a non-steroidal anti-inflammatory aid (Ketoprofen 80 mg) for five consecutive days. The patient was also administered antibiotic therapy in the perioperative phase, starting the night before surgery for 4 days, using 500 mg of Amoxicillin and Clavulanate every 8 h. The patient was examined for the first time one week later and then 3 and 6 months after surgery D–F.The second case was an 80-years-old woman of Caucasian origin who referred bilateral pain in the mandibular body. The patient was treated with continuous therapy with bisphosphonates.In this second case, despite the absence of fractures, it was decided to intervene and apply an epi-mucosal fixation because of the very high risk of pathologic fracture due to the osteonecrosis outbreak. Surgery was performed under general anesthesia. After the debridement and removal of the necrotic bone with sequestrectomy and bone trimming, also in this case we proceeded to an epi-mucosal fixation performed using SMART Lock screws and plates without elevating the mucoperiosteal flap C. As in Postoperative course was without complications. Postoperative therapy comprised oral hygiene instructions. Application of 0.2% chlorhexidine solutions twice a day, an evening application of 0.2% chlorhexidine gel upon the sutured incision lines, and administration of a non-steroidal anti-inflammatory aid (Ketoprofen 80 mg) for five consecutive days. Even in this case, antibiotic therapy was administered in the perioperative phase, starting the night before the surgery and up to 4 days after, using 500 mg of Amoxicillin and Clavulanate every 8 h. The patient was examined for the first time one week later and then 3 and 6 months after surgery D–F.Post-operative pain was assessed with the VAS score. The VAS score is a tool for measuring the subjective characteristics of pain experienced by the patient. The scale consists simply of a strip of 10 cm paper at the ends presenting two “end points” that are defined as “no pain” and the “worst pain that I can imagine”. The patient is asked to mark the pain at a point on the scale as perceived at that moment. The interval between the two ends (end points) is marked every centimeter and allows us to assign a value to the pain perceived by the patient. The initial score can be used as a subjective assessment of the pain experienced by the patient. The subsequent measurements required allow health professionals to understand if the pain is actually reducing and to what extent.Ability to wear a prosthesis was possible also using the epi-mucosal fixation devices for stabilizing the dental prostheses, with the miniplates and self-locking screws acting as a bar supporting the prostheses. For case one, patient physical examination showed no obvious swelling of the face. CT examination showed a lithic area in the mandibular horizontal branches, which appeared subverted and fractured on the left side A. A panoFor case two, patient physical examination showed no obvious swelling of the face. Oral examination showed no irregularities.CT examination showed that there was a lithic area in the lower branch of the mandible. Although there were no fractures, the subversion of the normal organization of the bone exposed the patient to a high-risk for pathological fracture. Radiographic evidence showed an extensive osteolysis compatible with stage 3 MRONJ A,B. Mucosal integrity: Absence of necrotic bone exposure;Absence of residual infection: Absence of purulent exudate and reduction of swelling;Pain reduction: Evaluation of the VAS score.In both the presented cases treated by our protocol associating surgical removal of the necrotic bone outbreak by surgical drilling and smoothing of sharp edges in the affected segment followed by application of autologous PRF we achieved good results. Post-operative clinical conditions were evaluated by analyzing the following results:We achieved good bone healing with absence of necrotic bone exposure, mucosa healing with complete necrotic site closure, and absence of residual infection without any swelling or residual fistulas.Patients were able to wear a dental prosthesis without any referred pain at rest or during soft diet mastication.We followed the first patient with periodic controls at one, three, and six months. In the post-operative controls, we could detect a progressive healing of the mucosa up to a final result, with complete mucosa healing without any signs of necrosis or infection. A significant reduction in pain was assessed by the VAS scale. Before the operation she reported a pain score on the VAS scale between 9 and 10, with the need to use painkillers. A few days after the operation, she had already reduced the use of painkillers. In the three-month post-operative control, she completely eliminated the use of painkillers, having a score on the VAS scale of 0, with no pain. The patient died two years after the operation as a result of breast cancer general complications.In the second case, after the operation, we also followed the patient with periodic controls at one, three, and six months. In post-operative controls we observed that there was a progressive healing of mucosal integrity and infection. In this second case too, the patient had a progressive reduction of pain and no signs of necrosis or infection. Before the operation she reported a pain score on the VAS scale of about 8, with the need to use painkillers. Shortly after the operation she reduced the use of painkillers. In the one-month postoperative checkup she eliminated the use of painkillers, having a score on the VAS scale of zero with no pain.Both cases were treated with our new protocol, consisting of the combination of a well-demonstrated conservative treatment by autologous PRF and surgical removal of the necrotic bone area combined with epi mucosa mandibular fixation in case of fracture risks or conclamant fracture in the necrotic bone segments. By our new original epi-mucosal fixation technique it was possible to achieve close fixation of the segment, avoiding large periosteal elevation in the affected area of the jaws.In the scientific literature, high doses of bisphosphonates or denosumab are associated with an increased risk of MRONJ compared to low dose regimens .n = 318) and 36.9 months for those with prostate cancer (n = 147) [For patients who received continuous denosumab during the blinded treatment phase plus the open-label extension phase, the incidence of confirmed MRONJ, adjusted for years of patient follow-up, was 1.1% during the first year of denosumab treatment, 3.7% in the second year, and 4.6% per year thereafter. The median cumulative exposure to denosumab was 43.0 months for those patients with breast cancer  and accompanied by smoothening of sharp bony edges and closure of the wounds, and then monitored until complete mucosal healing is achieved.In general, well-designed prospective clinical trials and non-interventional studies that investigate MRONJ management approaches in patients with cancer and bone metastases are lacking. Furthermore, inconsistent outcome measures  are used in all studies . This meThe current AAOMS guide recommends soft tissue debridement to treat irritation and infection in association with necrotic bone removal in stage 2, while bone resection at the necrotic area is considered in stage 3 . The maiIn our study, we developed a new protocol for the treatment of patients in stage 2 and stage 3 MRONJ causing segment fracture or showing high-risk for fracture. In MRONJ treatment there is a contraposition between two requirements: One is to remove the necrotic bone area, the other one is to prevent new necrosis by avoiding periosteal elevation in affected the area. To solve these two opposite requirements, we developed a new technique where bone resection was performed and fixation of the fractured bone segments in the affected area or preventive fixation of the resected area at risk of fracture was performed by our epi-mucosa fixation technique. This technique was already validated and published for jaw reducible fractures; because of the similar condition for reducible jaw fractures in MRONJ cases and in non-affected patients, we adopted this technique in the two reported cases. It was the first time the technique was adopted in MRONJ cases, hence the scientific relevance. In this way, it was possible to avoid periosteal elevation with a subsequent bone nutrition impairment and necrosis extension risk. In this new technique, the fixation is performed in closed surgery by fixing the bone plates over the mucosa using self-locking screws, as in an external fixation system. Conservative treatment by autologous PRF is also used in combination, to enhance and promote soft tissue and exposed bone area healing.We developed the epi-mucosal fixation technique for reducible or well aligned fractures of the jaw; in these cases, fixation of the two bone segments is performed after close reduction of the fracture, avoiding surgical trauma and periosteal elevation, thereby preserving bone nutrition. In this way, we can ensure less surgical trauma with earlier healing of the lesion for the patient.As shown in our previous study, the main indications for this technique were in well aligned fractures of the jaws  or in dislocated jaw fractures that can be reduced by closed manipulation without any incision. Particular indication for this technique is in case of multi segmented fractures with high risks for bone resorption and infection in case of periosteum elevation because of lack of nutrition of the bone fragments . Long thThe main advantages of this technique are the minimum surgical trauma suitable for elderly patients, avoiding the risk of devascularization of the fragment even in comminuted or multifocal fractures; in this way, the quality and speed of the healing process is improved .Other advantages are an easier removal of fixing devices, avoiding further surgical time, unlike in current techniques with sub-periosteal miniplates and screws, and no risk of periodontal damage, unlike in ferule methods, with lower costs and greater benefits of results ,11. It iWith the use of this new epi-mucosa fixation technique, we were able to shorten the healing time with minimal surgical impact on the patients affected by MRONJ with fractured or weakened bone segments. In conclusion, the intraoral epi-mucosal fixation system is comparable to external fixation devices, with the advantages of avoiding trans-cutaneous pins or cumbersome devices with aesthetic and functional impairment. For the minimum device size, intraoral placement of the system is also possible for the molar areas using a ratchet screwdriver and contra-angle tips. Particular attention must be paid to the selection of the screw insertion sites in the interalveolar bone septa, avoiding damage to the dental roots.Analyzing the result of the two cases treated by our technique, it was possible to achieve good results, combining the most effective treatment, even for advanced cases of MRONJ (stage 3). Excellent results were obtained, limiting risks and disadvantages, also in cases with high-risk for bone fracture or cases of effective fractured segment in necrotic bone segments. The advantages are: Non-invasive surgical procedure; ability to stabilize a bone segment at risk for pathologic fracture; limited risks for necrosis extension; ability in solving pain and necrosis related symptoms achieving mucosa healing.In our cases, we did not find any complications related to pain during plate and screw fixation, and there was no infection around the sites of screw insertion and no screw weakening or plate mobilization. Even if the epi-mucosal fixation procedures are already used in close reducible maxillofacial fractures, the number of cases was limited, and additional studies with a larger number of cases are needed to finally assess the reliability and effectiveness of this procedure in MRONJ patients, even if showing promising results in our cases.


Initial study of the mechanical properties of the element showed a structural behavior that would satisfy the requirement for schematic architectural cladding configurations, indicating a unique hysteretic behavior of the material. This paper further investigates the hysteretic capacities of L-FMFRP, examining the behavior under repeated loading and the effect of its internal material architecture. Parallels to entangled materials are suggested for a deeper understanding of the phenomenon, and the potential future application as an energy-absorbent material for façade cladding is outlined.L_FMFRP is an architectural fiber composite surface element with an airy internal structure and variable section. This architectured material is the product of an alternative design and fabrication process that integrates  Fiber-reinforced polymers (FRPs) are the composite outcome of advanced fibers and polymer resins, making a family of high-performance materials that offers high strength-to-weight ratio, durability and versatility. In the past decades, numerous types of FRPs have been developed and introduced into extensive use across industries, from aeronautics and space, to infrastructure, automotive and consumer products. In the construction industry, FRPs are widely used for civil infrastructure , rehabilElements of FRPs are traditionally manufactured based on rigid molds. A compact laminate is made by pressing a number of fiber layers, mainly under the form of textile fabrics, over the mold. The composite piece is shaped by the mold’s morphology, assuring conformity to the requested designed shape as well as material homogeneity . While bfabric materiality FRP” (FM-FRP) was coined to represent the integration of textile-related practices, techniques, design paradigms and material qualities into the world of fiber composites, as novel FRP material systems [architectured materials, or metamaterials [This research tackles the alternative shaping of FRPs on the fabric level, enhancing the textile qualities of the fiber constituent of the composite. The term “ systems . FM-FRP  systems   or in raterials ).In the field of composites, the integration of voids in the material architecture is mainly applied as tubular hollow composites, based on techniques such as braiding, knitting, or spacer . Such hoThe preliminary testing of L-FMFRP material demonstrated its general suitability for service as an architectural façade element . In partIn the past two decades, there has been a growing concern for safety and security in the built environment. From the scale of urban planning to material design, efforts are being invested in the creation of resilient built environments that would actively contribute toward facing the challenges of terrorism and of natural disasters . The gro(a)Test the unloading behavior: verify whether or not the unloading curve is inversely similar to the loading curve and identify the elasto-plastic characteristics of the material behavior.(b)Test repeated cycles: observe the element during multiple loading–unloading cycles to identify a possible drift in the cyclic curves.(c)Test various folding patterns: investigate the effect of different folding patterns on the overall elasto-plastic behavior of the element.Following the initial indications for the potential energy-absorption capacities and interesting properties of L-FMFRP under compression, three issues were defined for further investigation through compressive tests: Two experimental campaigns were carried out for the investigation of the above three issues. The main results of these tests are the observation of a phenomenon of hysteresis and some correlations between the shape of the loading–unloading paths and the meso-architecture of the specimens. 2: Prepreg E-glass 7781: fabric thickness 0.23 mm, weave pattern 8HS; resin content 30% +/−3%, Tg 124°. Testing was realized on L-FMFRP specimens, all made of fiberglass–epoxy prepreg 0/90 satin weave of 300 g/mThe samples were fabricated according to a protocol that was developed in the framework of previous research , which c(a)Perforation of the prepreg sheet according to pattern .(b)Sliding metal rods into the perforated lines of holes to serve as pleating guides.(c)Gathering the pleats by temporary knots along the pleating guides .Pleating of the single sheet: (a)Stacking the pleated sheet by superposition.(b)Constraining the assembly by a jig.(c)Curing.Forming the ‘laminate’: All samples were composed of two prepreg layers, 600/200 mm each. The stacked assembly was oven-cured at a temperature of 125 °C for 2 h.The testing was carried over three samples of identical pattern and similar internal structure a. The plTesting was carried over four samples, each with a different pleating pattern. Two pleat types were used: a ‘simple pleat’ pinched along two rods (top and bottom) and a ‘full pleat’ pinched along three rods  b. Each sThe testing was realized in an electromechanical tension–compression MTS testing machine of 100 kN capacity, with the samples placed between two steel plates (20 mm thickness) for levelling and load distribution over the surface. An average of 20 loading cycles were realized per sample, at constant displacement rate . The maximal load was averagely 3000 N (excluding the first cycles of the setting and the last cycles of the rupture).The testing was realized in an electromechanical tension–compression Instron testing machine of 10 kN capacity, with the samples placed between two steel plates (20 mm thickness) for levelling and load distribution over the surface .A preliminary study of L-FMFRP’s structural characteristics was carried out in the framework of previous research, testing the surface element under tension, compression and bending. The results showed a structural behavior that would satisfy the requirements for different theoretical schematic architectural cladding applications . The comThe results of the first experimental campaign showed a significant difference between the loading and the unloading curves. When plotting the force against deformation, the two curves form a loop with an area enclosed between the curves . The loaIncreasing the applied force beyond the previously achieved threshold generates an irreversible plastic deformation, visible in the dented curve section. The repeated loading thereafter within the newly achieved threshold keeps a reversible elastic behavior with smooth curves. A small shift in the zero-state at each loading cycle is noticeable (within a similar threshold), showing an accumulated minimal irreversible deformation . However, as the number of cycles increases under the same threshold, the accumulated irreversible deformation decreases .A similar loop curve appears among all three samples, despite their relative differences due to manual fabrication and material self-organization. A superposition of loops of different samples under identical loading thresholds strongly resembles the curves and the enclosed area between the loading–unloading . The results of the second experimental campaign show the variation of the hysteretic loop between the samples of different pleating patterns. General similarity remains between the samples, as all demonstrate the hysteretic loop. However, the enclosed area of the loops as well as the overall steepness of the curves vary between samples. The plotting force against the normalized displacement of all samples combined shows that the samples of the full pleats  go through larger relative deformation compared to the simple pleats . Accordingly, the enclosed area of their loops is larger, showing a stronger difference between the loading and unloading paths . A compaThe comparison between single and triple pleats of the same kind shows a similar behavior for both simple and full pleats . The higThe experiments show a loop of a defined deformation cycle (loading and unloading curves) enclosing an area, which indicates a loss of elastic energy in the process, allegedly attributed to friction. Such behavior is known as hysteresis, occurring in a variety of materials, structures and systems, where the dependence of a physical system upon its history is expressed as a non-linear behavior with a retardation of the effect when external forces acting upon the system are changed. This phenomenon is typically associated with materials of visco-elastic behavior such as elastomers , and is The similarity of load–unload loops between the different samples clearly demonstrates that the hysteretic behavior is a typical property of the L-FMFRP architectured material. While the samples show significant variations in their specific material configuration, due to manual manufacturing and material self-organization, the strong similarity of hysteretic loops between the samples indicates that this property is not sensitive to specific internal configuration . Rather,The effect of different parameters of the material architectures of L-FMFRP and its behavior can be initially observed through the comparison between different pleating patterns (campaign 02). Although the isolation and modelling of the effect of each parameter requires further study, the difference between the full and simple pleats is noticeable in the typical loading–unloading paths . The twoThe role of the connection between the layers is to be further studied. The contact points between the pleated layers of the laminate are essential for the material to perform as a constrained unit under load and prevent immediate sliding of the layers. However, the displacement of the layers during compression shows a relative sliding of the layers. This sliding is within the elastic range of the material and its contact points, since the meso-scale architecture of the material is not destroyed through the extensive loading, and the layers within each sample remain connected. Looking at the analysis of entangled materials, the connection between the components’ contact length and permanence of contact seems to be a critical architectural parameter in the material performance . A fundaThe role of friction in the hysteresis of entangled material was studied previously ,37, indiThe L-FMFRP material system product resembles a thick panel with highly articulated surfaces of extreme low density. It stands in contrast to typical FRP panels: its section is not uniform and dense, but variable and airy; it has an intricate internal configuration set by the pleats and the partial adherence between the layers. This, in turn, affects and determines the characteristics of the overall resulting element, its stiffness and strength. L-FMFRP blurs the boundaries between material and structure, and thus can be considered an ‘architectured material’, for which the overall macro-scale behavior is related to two underlying scales: the micro-scale, where the density and the direction of the fibers play a principal role in defining the textile’s properties; and the meso-scale, where a complex geometry and a set of internal bonds give rise to a particular, airy, structure. The finite deformation properties of L-FMFRP and the hysteresis phenomena demonstrated in the experiments indicate a potential capacity of the material system for energy absorbance. The experiments show that this property is inherent to the material’s architecture, and is affected by parameters such as pleat type and number. Such a capacity for energy absorbance, if further investigated and developed, could prove to be beneficial for architectural cladding applications, as retrofit or for new structures. Other energy absorbent composite structures designed for crashworthiness applications could serve as a reference . While tAn initial estimation is to be carried out to assess the capacities of the L-FMFRP system to withstand the range of loads typically considered for windborne debris, blast mitigation by sacrificial façade systems and general energy dissipation for fluctuating air pressure. Referring to its crashworthiness properties, its characterization should refer to indicators of performance such as the specific energy absorption (SEA), energy absorption (EA) capacity, crush force efficiency (CFE), mean crushing force (MCF) and sound transmission loss (STL) . With thThe further investigation of L-FMFRP calls for a deeper understanding of the internal physical phenomena of energy dissipation in the system and its determining parameters. Wishing to augment its capacities for energy absorbance, the relation between friction, structure and geometrical pattern is to be evidenced. Monitoring the heat loss and the sound emitted throughout the full loading cycle could indicate the fractional energy loss that takes place. The role of contact points, their evolution along compression cycles, their effect on friction, their relation to the folding pattern and the effect of those on the hysteresis level should be further investigated in order to optimize the energy absorbance of the system. Through further physical experimentations and mathematical modelling, control of the system’s performance could be obtained through the variation of the geometrical folding pattern and raw material properties.