Introduction YouTube is the most popular video-based source of information on the Internet. It is accessed by over 1 billion users, which approximates to almost one-third of all Internet users. Orthopaedic video content published on YouTube is not screened and does not go through an editorial process, and most videos do not have information about authorship or appropriate references. Users who do not have the knowledge to assess the accuracy and reliability of the source may be misinformed about their medical condition. Previous studies have evaluated the quality of YouTube content for information in orthopaedics such as meniscus,kyphosis, and anterior cruciate ligament (ACL), but the quality of frozen shoulder videos on YouTube has not been investigated. The purpose of this study is to evaluate the quality and educational value of YouTube videos concerning adhesive capsulitis.MethodsA YouTube search was performed using the term "frozen shoulder." Videos were excluded if they had no audio, were in a language other than English, or were longer than 10 minutes. A total of 70 videos were screened, and the first 50 videos that met the inclusion criteria were evaluated by three observers. Six video characteristics were extracted, and videos were categorized by source and content. Quality and educational value were assessed using the DISCERN , Global Quality score , and a Frozen Shoulder-Specific Score .Results The mean video duration was 242.46 ± 164.32 seconds. The mean number of views was 137,494 ± 262,756 and the total view count across 50 videos was 6,874,706. The mean DISCERN, GQS, and FSSS scores were 2.72 ± 0.85, 2.37 ± 0.895, and 4.42 ± 3.15, respectively. The video sources were primarily from non-physician healthcare professionals (32%), and most of the video content was focused on disease-specific information (50%). Significant between-group effects were observed for the DISCERN score and video source (P = .005), with videos from academic sources having the highest mean DISCERN score. DISCERN scores also differed significantly based on video content (P = .007), with disease content having the highest DISCERN score. Both GQS and FSSS scores differed significantly based on video content (both P < .001) but did not differ significantly based on the video source.ConclusionsInformation about frozen shoulder on YouTube is low quality and has limited educational value. Thus, providers for orthopaedic conditions should warn their patients and provide better alternatives for education. Today, the easiest way to access quick and broad medical information is to use the internet. A recent estimate showed that there are 4.66 billion active internet users worldwide, which is 59.5% of the global population . With thYouTube is the most popular video-based source of information on the Internet. It is accessed by over one billion users, which approximates to almost one-third of all internet users . OrthopaAdhesive capsulitis, also known as "frozen shoulder," is one of the most common disorders in sports medicine, characterized by pain and stiffness of the shoulder. It is a progressive disorder that restricts both active and passive range of motion of the shoulder, and it is more common in people between the ages of 40 and 60 . PreviouSearch strategyThe term "frozen shoulder" was searched on YouTube on February 13, 2022, in a cookie-free, cache-cleared, private browsing setting on Google Chrome. The search results were based on YouTube's default settings of proposed relevance. Videos were included if they were relevant to the frozen shoulder. Videos were excluded if they had no accompanying audio, narration, and/or text, were in a language other than English, or were longer than ten minutes in length since viewer engagement significantly reduces in lengthier videos . The firVideo parameters and evaluationsVideo parameters including video length, number of views, video source/uploader, duration on the platform, and number of likes were extracted. The view ratio was calculated by dividing the number of views by the duration on the platform. Videos were classified into one of seven source categories: academic, commercial, medical source, non-physician healthcare professional, patient, physician, or trainer. Videos were classified into one of six content categories: patient experience, disease-specific information, exercise training, surgical technique/approach, nonsurgical management, or advertisement.Three instruments were used to assess the quality of the information in the videos: DISCERN, Global Quality Score (GQS), and Frozen Shoulder-Specific Score (FSSS). DISCERN contains 15 questions, each scored on a 5-point scale, and is used to evaluate the quality of consumer health information regarding treatment options . In thisThree authors collected data and evaluated the videos. If videos fit into more than one content category, they are classified into the category that captures the primary focus of the video content. Disagreements about classification were settled by discussion and consensus.Statistical analysisVideo characteristics, video reliability, and video quality scores were quantified using descriptive statistics. One-way analysis of variance (ANOVA) was used for parametric data and its non-parametric equivalent, Kruskal-Wallis, was used for nonparametric data to determine whether FSSS, GQS, and DISCERN scores differed based on either video source or video content. If the Kruskal-Wallis test was significant, then a Dunn Test was performed to determine which exact groups within the video source and video content differed significantly. Interobserver reliability defined by interobserver correlation coefficient scores (ICC) was 0.68  for DISCERN, 0.94  for FSSS, and 0.88  for GQS. All statistical tests were performed using R Programming (version 4.1.2). P < .05 was considered to indicate statistical significance.A total of 70 videos were screened before 50 met inclusion. The mean video duration was 242.46 ± 164.32 seconds. The mean number of views was 137,494 ± 262,756 and the total view count was 6,874,706. The mean view ratio was 95.42 ± 145.87 and the mean number of days since uploaded was 1346.46 ± 1034.67. The mean number of likes was 1264.98 ± 2912.41. The mean DISCERN, GQS, and FSSS scores were 2.72 ± 0.85, 2.37 ± 0.895, and 4.42 ± 3.15, respectively. Videos were primarily categorized into disease-specific information (50%), followed by nonsurgical management (40%), and then patient experience (10%). The video sources were primarily from non-physician healthcare professionals (32%) or physicians (30%).The DISCERN scores differed significantly based on video source (P = .005), with videos from academic, commercial, and physician sources having the highest DISCERN scores . DISCERN scores also differed significantly based on video content (P = .007), with disease content and nonsurgical disease management having the highest DISCERN scores . The FSSS scores differed significantly based on video content (P < .001), with disease and patient experience content having the highest FSSS scores, but did not differ significantly based on video source (P = .09). The GQS score differed significantly based on video content (P < .001), with disease and patient experience content having the highest GQS scores but did not differ significantly based on video source (P = .057)  and between nonsurgical management and disease content (P = .006). The Dunn test showed significant differences between nonsurgical management and disease content for FSSS scores (P < .001) and GQS scores (P < .001). Among video sources, the Dunn test showed significant differences in DISCERN scores for academic versus medical sources (P = .009), academic versus patient (P = .031), academic versus trainer (P = .019) and commercial versus trainer (P = .029).Three separate multivariate linear regression models were constructed to determine the influence of video characteristics on the DISCERN, GQS, and FSSS scores. Significant positive independent predictors of GQS included number of days uploaded  and the view ratio . GQS had no significant negative independent predictors. Significant positive independent of FSSS included the number of days uploaded  and the view ratio . FSSS had no significant negative independent predictors. DISCERN did not have any significant positive or negative independent predictors from video characteristics.The findings of this study were as follows: (1) videos concerning frozen shoulders are highly watched by YouTube users with a total view count of 6,874,706 across the 50 videos; (2) the study had a mean DISCERN of 2.73, GQS of 2.38, and FSSS of 4.42 suggesting low-content reliability; (3) most frozen shoulder video content is disease-specific information and the most uploads are from non-physician healthcare provider sources; (4) DISCERN scores differed significantly based on video content and video source while GQS and FSSS scores differed significantly based on video content, but not video source; (5) video characteristics such as the number of days uploaded and the view ratio are significant positive predictors of GQS and FSSS scores; meanwhile, DISCERN had no individual predictors.Due to the ease of access to information, patients are increasingly using YouTube as a source of information . Our stuThis study had a mean DISCERN of 2.73, the GQS was 2.38, and the FSSS was 4.42. These results suggest that the quality of information regarding frozen shoulders obtained from YouTube is poor, which is consistent with other YouTube video studies done in orthopaedics. When evaluating YouTube videos regarding kyphosis . CassidyIn addition, while academic sources had the highest scores for DISCERN (3.78), GQS (3.22), and FSSS (7.22), all well above the mean for each respective score, academic sources only accounted for 6%, or 3 out of the 50 videos that were analyzed. In contrast, 16 out of 50 videos, or 32% of the videos, were uploaded by non-physician healthcare professionals, but these videos had lower DISCERN (2.48), GQS (1.88), and FSSS (2.90) scores than the mean of the scores across the 50 videos. Given the low number of uploads by academic sources and high uploads but low-quality information from non-physician healthcare providers, YouTube users have a lower chance of coming across reputable information concerning frozen shoulder. Regarding content categories, disease-specific information had the highest DISCERN (3.12), GQS (2.94), and FSSS (6.44) scores, all above the mean, and accounted for 25% or 50% of the videos analyzed. Videos describing non-surgical management accounted for 40% of the videos; however, they had relatively low DISCERN (2.43), GQS (1.73), and FSSS (1.93) scores compared to the mean. Further analysis from this study showed that DISCERN scores differed significantly based on video content and video source, with disease-specific information and academic sources having the highest DISCERN scores. GQS and FSSS scores only differed significantly based on video content, with disease-specific information having the highest scores for both GQS and FSSS.Regression analysis revealed that the number of days uploaded and the view ratio were significant positive predictors of both DISCERN and GQS. This implies that more recent videos have had less reliable content regarding frozen shoulders. This could be due to the significant growth of YouTube as a platform for content creators. The quality of videos has decreased with more content being created by non-physician content creators. It is also interesting to note that FSSS had no significant predictors, and the number of views and likes was not a significant predictor for any score. This demonstrates that the quality of information for frozen shoulder videos cannot be predicted by the popularity of the video.There are a few limitations inherent to our study. Our study utilized DISCERN, GQS, and FSSS, which are highly regarded but not validated assessment tools. Despite this, numerous other studies that evaluated the reliability and accuracy of internet content for orthopaedic diseases have used these evaluation methods to provide reproducible measures -5,13. HaYouTube is becoming an increasingly powerful tool to obtain many forms of information. Therefore, it is important for healthcare providers to be aware of its use and potential for misuse, as there is currently no peer-reviewed system in place for YouTube videos. Thus, providers should engage with their patients by asking them if they have used online resources to understand their condition and should help patients better utilize these resources. While videos on YouTube concerning frozen shoulder are highly viewed, they are, on average, of low quality and low educational value. It may be prudent for those who utilize YouTube to learn more about the risk factors, pathophysiology, symptoms, and medical and surgical management associated with frozen shoulder by complementing their education with other sources that are peer-reviewed and scientifically supported. If providers were able to properly address these resources with patients and inform them about their use, they may be able to help patients find a sense of control in their care for frozen shoulders.


Wnt signaling is relevant for a wide range of biological processes, including reproductive function. The function of Wnt10a in female fertility, however, remains obscure. In the present study, we explored the structure and function of the female reproductive organs in Wnt10a knockout (KO) mice. The expression of β-catenin signaling was significantly lower in the ovaries of the Wnt10a KO mice compared with wild-type (WT) mice. In addition, the estrous cycles were disrupted, ovarian follicles were diminished, and endometria were thinner, accompanied by lower serum estrogen levels, and higher testosterone and progesterone levels in Wnt10a KO mice. The expression of the ovarian cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) was significantly lower in Wnt10a KO mice. We detected no significant changes in the levels of the gonadotropins between WT and KO mice. Together, our findings indicate that deficiency of Wnt10a causes female infertility through β-catenin and Cyp19a1signaling pathways in mice. Mammalian female reproductive functions depend on tight regulation of the hypothalamic-pituitary-gonadal axis A woman's fertility depends upon the timely and appropriate orchestration of the ovaries, uterus, and their functions. Dysregulation of the signaling pathways involved in female reproduction leads to difficulties in becoming pregnant. Infertility in humans is defined as the failure to achieve pregnancy during 12 months of regular sexual intercourse. The prevalence of female infertility is drastically increasing, affecting approximately 48 million women throughout the world, and is often associated with significant physical and emotional changes The ovaries are a pair of female organs in the pelvis. The primary function of the ovaries is to generate and release oocytes regularly, and to produce steroid hormones. The ovarian follicle, composed of different numbers and types of cells, is the basic unit of the ovary and provides the environment for protecting and nourishing the oocyte. Ovarian follicles growth and maturation are controlled by well-orchestrated factors, including the pituitary FSH, LH, various cytokines, and several local signaling pathways Accumulating evidence reveals a critical role of the Wnt signaling pathway in maintaining female fertility The Wnt10a is part of a large family of Wnt genes. Wnt10a gene mutations were first identified in odonto-onycho-dermal dysplasia, affecting the teeth, nails, and skin Wnt10a KO mice were generated as described previously Daily vaginal smears from 12-week-old mice were collected with cotton swabs at the same time each morning (8:00-9:00 a.m.) for 12 successive days. Dried smears were stained with Giemsa stain, examined microscopically, and the estrous cycle stage was classified according to established criteria The WT and Wnt10a KO mice were killed by intraperitoneal injection of a mixture of ketamine 50 mg/kg and medetomidine 1 mg/kg Paraffin sections of the mouse ovaries and uterus were deparaffinized in xylene and rehydrated in an ascending series of ethanol solution. After antigen retrieval, sections were treated with blocking solution. Sections were incubated with anti-β-catenin , anti-cytochrome P450 family 19 subfamily a member 1 , and anti-Wnt10a (1:5000). For generating anti-Wnt10a antibody, rabbits were immunized with a synthetic peptide corresponding to amino acids 160-172 of the mouse Wnt10a. The sera of the immunized rabbit were then isolated and purified Blood samples were collected at 12 weeks of age and centrifuged at 1500 ×g for 10 min at 4 °C to separate the serum. The serum concentrations of 17β-estradiol, testosterone, progesterone, FSH, and LH were measured using enzyme-linked immunosorbent assay kits, in accordance with the manufacturer's instructions . The absorbance of light was determined with a microplate reader .Total RNA was extracted from the ovarian tissues at 12 weeks of age with Trizol reagents (Invitrogen). First-strand cDNA was synthesized with Superscript II RT (Invitrogen) in accordance with the manufacturer's instructions. The cDNA was applied to evaluate mRNA expression levels of Wnt10a, β-catenin, FSH receptor (FSHR), steroidogenic factor 1 (Sf1), and GAPDH in the ovarian tissue. The following specific primers used: Wnt10a , β-catenin , FSHR , Cyp19a1 , Sf1 , and GAPDH . Quantitative real-time polymerase chain reaction (PCR) analysis was performed using the TaqMan fluorogenic probe method with a Step One real-time PCR system . Cycling conditions were as follows: 50 °C for 2 min, 95 °C for 10 min followed by 45 cycles of 95 °C for 15 s and 60 °C for 1 min. The mRNA expression levels were normalized with the GAPDH mRNA expression level.Ovarian tissues of WT and Wnt10a KO mice at 16 weeks of age were lysed in RIPA , centrifuged at 12,000× g for 30 min, and the supernatants were collected for analysis. The proteins were separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to Immun-Blot polyvinylidene difluoride membranes  with a semi-dry blotter. The blotted membranes were treated with 5% skim milk in 10 mM Tris, 150 mM NaCl and 0.2% Tween-20 and incubated for 1 h at room temperature with the primary antibodies anti-Cyp19a1  and anti-GAPDH . The immunoblotting membranes were then incubated with a peroxidase-conjugated secondary antibody  for 60 min and visualized with an ECL kit . Bands of the target proteins were analyzed using the Scion Image software program .DNA microarray analyses were performed using 3D-Gene , as described previously t-test was applied to analyze differences between the KO and WT mice, using SPSS software . The difference is considered to be statistically significant when p values < 0.05.The experimental data are expressed as means ± standard deviation (SD), and an unpaired Compared with the WT mice, Wnt10a KO mice were smaller in size. The Wnt10a KO mice also tended to have lower body weights at 8 weeks of age. From 12 to 24 weeks of age, the body weights were significantly lower in Wnt10a KO mice  in Wnt10a KO mice (Table The present study revealed that Wnt10a KO mice had prolonged and disrupted estrous cycles, decreased ovary size and the number of ovarian follicles, thinner uterine endometrium, lower serum estrogen levels, and higher testosterone and progesterone levels, reflecting the female reproductive dysfunction.The periodicity of estrous cycle in mature females is a direct result of the cyclic alterations of the female reproductive functional status. During estrous cycle, the circulating levels of LH, FSH, estrogen, and progesterone exhibit rhythmic alterations The ovarian follicle, composed of different numbers and types of cells, is the basic unit of the ovary, and provides the environment for protecting and nourishing the oocyte. Ovarian follicular development is a complex dynamic process, which is controlled by well-orchestrated factors, including the pituitary FSH, LH, various cytokines, and several intracellular signaling pathways The endometrium is a highly dynamic tissue and undergoes periodic alterations morphologically and functionally. Several kinds of Wnt receptors are expressed in the endometrium or stroma of the uterus Ovarian follicular granulosa cells are key cells in steroid hormone production and secretion. β-Catenin is an essential transcriptional regulator of Cyp19a1, activating the expression of Cyp19a1 in the granulosa cells through the functional interactions with Sf1 in vivo. Further studies are needed to explore the relationship among the Wnt signaling pathway, GnRH, gonadotropins, and their receptors.The gonadotropins, FSH and LH, and their receptors, FSHR and Lhcgr, play a central role in governing reproductive competency or fertility In conclusion, our findings demonstrate that Wnt10a is required for female fertility through β-catenin and Cyp19a1 pathways to maintain the normal functions of the ovary and uterus, a regular estrous cycle, and the dynamic balance of the steroid hormones.


Regular and long-term monitoring of coastal areas is a prerequisite to avoiding or mitigating the impacts of climate and human-driven hazards. In Africa, where populations and infrastructures are particularly exposed to risk, there is an urgent need to establish coastal monitoring, as observations are generally scarce. Measurement campaigns and very high-resolution satellite imagery are costly, while freely available satellite observations have temporal and spatial resolutions that are not suited to capture the event scale. To address the gap, a network of low-cost, multi-variable, shore-based video camera systems has been installed along the African coasts. Here, we present this network and its principle of sharing data, methods, and results obtained, building toward the implementation of a common integrated coastal management policy between countries. Further, we list new contributions to the understanding of still poorly documented African beaches’ evolution, waves, and sea level impacts. This network is a solid platform for the development of inter-disciplinary observations for resources and ecology , erosion and flooding, early warning systems during extreme events, and science-based coastal infrastructure management for sustainable future coasts. Many coastal areas have undergone extensive modification and development over the past few decades, greatly increasing their vulnerability to both the anticipated effects of global climate change and the natural coastal dynamics4.Coastal areas contain some of the world’s most diverse and productive resources that support a variety of economic activities, including fisheries, tourism, recreation, and transportation. They are, nevertheless, extremely vulnerable to human intervention and climate change. Their recreational, ecosystem and protection services and economic values give them high societal attention, especially given that these areas are home to more than a trillion dollars' worth of infrastructure and investments globally5. Accordingly, several cities along the African coasts have more than one million inhabitants , logging for firewood and charcoal , sand mining , tourism , as well as onshore and offshore industrial activities . Such activities lead to pressures and conflicts over the use of resources, often resulting in environmental degradation, which can threaten their development potential . Small-scale fishing towns and natural ecosystems are often the first victims of the induced vulnerability, as they are highly sensitive to climate variability and change due to their low adaptive capacities, which are insufficient to cope with future climate change15.Africa's coastal zone extends over 41,184 km, covering 32 continental countries. Most of the continent's economic activities are located in coastal areas, with the presence of industrial zones around the main deep-water harbours. This has led in recent decades to a demographic explosion, and major and rapidly expanding cities on the coast. Indeed, each year, 10 million people are added to the urban population of sub-Saharan Africa17 and is therefore very exposed to ocean, climate and human activities impacts. Indeed, several recent works showed that in recent decades, the coastal environment has been facing several disturbances in wave forcing and shoreline stability in West Africa (e.g.22), in North Africa (e.g.24), in Central Africa (e.g.26), in Southern Africa (e.g.28) and in East Africa (e.g.29). These works highlight that as a result, the Africans coasts have become particularly vulnerable to erosion and flooding due to high-energy storm waves, extreme storm-surge water levels, sea level rise, and the high proportion of sandy low-lying coastlines. In West Africa, this vulnerability is particularly aggravated by the decrease in rainfall and the presence of dams on the main rivers (Volta and Niger Rivers) thus reducing the supply of sediments to the coast30. According to17, 20% of the 284 reported African coastal natural and cultural heritage sites are currently at risk from an extreme coastal event, including the iconic ruins of Tipasa (Algeria) and the North Sinai Archaeological Sites area (Egypt). The vulnerable sites are expected to triple by 2050 if greenhouse gas emissions are high17.Africa is the continent with the highest fraction of sandy beaches and low-lying coastal areas17, as several factors impede the sustainable development of these areas. Firstly, multi-scale morphological evolution remains poorly understood on tropical coasts31. To ensure more integrated and efficient management of coastal areas, it is important to characterize the natural coastal systems, the dominant processes, and their integrated effects adequately. Secondly, there are few local indicators to predict the large-scale  impact of coastal infrastructure construction and development, and changes in ocean forcing on coastal morphology32. Numerical modelling would undoubtedly enable the derivation of these types of indicators34. Nevertheless, calibration and improving existing models require large databases and better descriptions of nearshore processes. Thirdly, the discordance of actors and responsibilities among African countries, and sometimes even within the same country, have too often prevented the planning of effective and sustainable long-term solutions34. There are regional programs that synergize efforts to understand the dynamics of these environments such as the West African Coastal Areas (WACA) Management Program and the West African Coastal Observatory (ORLOA). But the results of these integrated programs and their impacts are not yet prominent.Decision-making for coastal management in Africa remains a challenge in the face of increasing risks to people and their property35). However, they are expensive and limited to timescales of days to weeks. The use of satellite radar and optical images enabled large spatial coverage of morphological variations. It is, however, limited to resolutions of tens of meters  with repeatability of several days (2–5 days for Sentinel 236), thus limiting the long-term observation of short-term processes. Moreover, altimetry, which measures sea surface variations, is still limited to areas a few km from the coast because of inappropriate sensors for the nearshore. While satellite earth observation represents a real opportunity to monitor African coasts37, they face several challenges, including the lack of ground truth observations. Buoys allow the measurement of hydrodynamic parameters  closest to the coast, but they are almost non-existent or unavailable along the African coasts. Purchase and installation of buoys are, however, expensive, and their maintenance is very complex, especially for a network covering large regions. And African coasts face a lack of historical data from tide gauges limiting the knowledge of climate-induced changes38.Effective decision-making for coastal management in Africa, therefore, requires the best and most up-to-date science. And this depends on the ability to collect long-maintained and real-time data, necessary to interpret and predict nearshore processes occurring at multiple temporal scales. Pioneering field measurement campaigns have been conducted for this purpose, providing crucial baseline measurements of short-term time-scales processes , intertidal topography , nearshore bathymetry , breaking wave height , sea level variations , nearshore currents . Video cameras allow for the collection of hard-to-access data on a continuous, long-term basis, effectively filling the data gap and, most importantly, ensuring effective monitoring of ocean conditions and beach changes2.Nearshore video camera systems are a low-cost option for high-frequency continuous long-term monitoring, with the advantage of being complementary to traditional measurement techniques  and particularly suited for tropical developing countries and open-wave areas31, and the network is currently being extended to West and Central Africa  in 2013Most of the parameters needed to understand the African coastal environments are measured simultaneously in this network: wave characteristics, water level variations and beach morphology. Figure 48, showed that wave dynamics are well captured by video camera systems , or require a lot of computational power, often out of the reach of African countries, to account for complex coastal processes and wave transformation.The main characteristics of waves . In addition, imagery from video stations is needed to refine estimates of wave contribution to sea level variations at the coast, which have so far been estimated by empirical formulations54. Indeed, waves undergo a series of complex transformations when propagating from deep-water to shallow water, resulting in the well-known process of wave set-up55 which adds a physical contribution to sea level variations. Using a collocated dataset, tide gauge, and wave buoy, Abessolo et al.53 showed that wave set-up contribution could be estimated from a video camera system, thus highlighting the potential of optimizing the location of coastal observation networks with respect to satellite ground tracks (as expressed in56). A new method for runup detection from video imagery57, consisting of detecting the instantaneous waterline from uprush and backwash using the Radon Transform, was introduced and validated using the the conventional color contrast method from RGB images and LiDAR measurements. The results show better detection skills even for adverse conditions.There is an obvious need to extend the satellite-based sea level record toward the coast, where altimetry cannot yet reach, and where tide gauges are difficult to install. Figure 58. The action of coastally-trapped waves (Kelvin waves) has also been demonstrated: a 7-cm change in sea level leads to nearly 2 m of horizontal terrace deformation44. Based on these video-derived morphological variations. Mingo et al.59 proposed and discussed a simple cubic parameterization based on the widely used Dean Number as the dominant control parameter for such beaches, while extending the common view of an equilibrium range profile as a power law of cross-shore distance.From the monitoring of topo-bathymetric variations in the storm-free environment of Grand Popo (Benin), beach profile evolution , waves (9%), and tide neap-spring cycles (5%) scales. These results show the role that the sea level anomaly can play in modulating the magnitude of wave action on the beach as stipulated by44.The importance of intraseasonal to interannual variation of sea level on beach dynamics was also evidenced at James Town (Ghana). Angnuureng et al.Rip currents usually occur at depth discontinuities in a sandbar, under a jetty or pier, which forces the discharging water into a thin corridor and accelerates the flow. These currents are one of the main hazards for beach users all over Africa and the world. And the studies carried out in Grand Popo (Benin) help to prevent and reduce the numerous cases of drowning deaths due to this phenomenon on the beaches of Africa.61 are the first to study the rip current system in West Africa using video images. Floc’h et al.62 developed a new method based on the colour processing of video images to detect the presence of rip currents via a change in turbidity. Morphological characteristics of the flash rip were computed from a set of instantaneous images and more than 50 rip events were counted per daylight, most occurring at low tide and migrating downdrift62.Castelle et al.63 described and tested a method based on the application of the Radon transform to directly estimate longshore currents using time-stack images. In addition, transient circulation was detected. Flash rips and surf eddies are transient horizontal structures of the order of 10 to 100 m, which can be generated in the surf zone in the absence of bathymetric irregularities. Using video-derived current fields, Marchesiello et al.65 revisited the processes of surf eddy generation with a new three-dimensional wave resolution model (CROCO) and provided a plausible demonstration of new 3D non-hydrostatic instability and turbulent cascade. Instant fields of surface current were retrieved from shore-based video cameras and unmanned aerial vehicles (UAVs) by an optical flow (OF) method named "Typhoon"66. Such computer vision algorithm estimates dense two-dimensional 2-component velocity fields from the observable motion of foam patterns in the surf zone.Almar et al.67. The multi-platform data collection strategy Angnuureng et al.69 was deployed for a year at Elmina (Ghana), through the use of the installed video camera system, drones , Sentinel satellite images, and a dumpy level . Angnuureng et al.68 revealed that data from local video cameras and drones are more effective for operational monitoring of shoreline changes at all-time scales compared to satellite imagery that is unsuitable for detecting daily or event-based beach changes needed by practitioners and management decisions. The obtained results indicated that the presence of the defense systems adequately protected the section of the beach, and a larger unprotected portion of the beach was out of balance with high erosion rates68. This is an example of the application of video data: to verify and evaluate the effectiveness of protective structures that are built along the coasts of Africa, and how they can induce morphological imbalances. This type of multi-platform monitoring allows coastal management to gauge the potential hazards associated with the building of houses and coastal infrastructure.The video camera system installed at the enclosed Elmina beach (Ghana) is used, first, to test multi-platform monitoring of coastal erosion and secondly, to evaluate the effectiveness of beach defense structures. Two 200 m long jetties were built on either side of the mouth of Benya lagoon and a seawall was built at the fish-landing site near Elmina Castle, 800 m from the north side of the mouth of Benya Lagoon25. Similarly, the Langue de Barbarie, near Saint Louis , has undergone significant morphological changes following the opening of an artificial breach70.The rapid development of video camera systems see Fig.  now offeThe African coastal camera network offers the potential for more effective and controlled management of coastal development and protection. For example, the relocation and construction of houses on stilts can be better coordinated, rather than leaving them to the vagaries of weather and flooding. Indeed, the regular monitoring of oceanic forcing allows one to foresee with reasonable accuracy the associated morphological variations and thus to define zones at risk. The African coastal camera network represents an excellent risk assessment that could support an early warning tool for the security of people and goods and help with the security of infrastructures.71, coastal geophysical processes  and public policies are parts of the greatest challenges to be addressed and should be seen as a priority for research in Africa. They recommended an integrative conceptual framework that encompasses the study of phenomena ranging from geophysics to society, and the development of coastal management policies. Other studies  have highlighted the interdependence between different coastal developments, whether along rivers or on the coast, on the overall sediment budget of the entire region, which is not limited to the geographic boundaries of countries. These studies recommended the development of a much more integrated large-scale coastal management plan. Unfortunately, the lack of timely, accurate, and trustworthy data has consistently been a problem in Africa. It still poses a significant obstacle to the efficient monitoring and assessment of development and intervention projects in the region, as data remain a critical tool for decision-making, development, and raw material for the quality of information.According to72, serve as a multi-variable monitoring platform, and exhibit the ability to provide relatively continuous, nearshore real-time estimates  for periods stretching to decades on a spatial coverage of several kilometres, although more suitable for smaller-scale applications. Traditionally, in situ measurement techniques and other types of remote sensing  are either too costly or inadequate, and face logistical difficulties in deployment. In-situ techniques involve placing a vast array of instruments at a limited number of locations, lacking the spatial resolution and coverage required for effective coastal zone management. Satellite imagery has a low temporal resolution for detecting daily or event-based beach changes and low spatial resolution for coastal studies and management decisions. Video cameras provide metric or higher resolution at the coast for spatial coverage of a few kilometres45 and cover timescales from seconds to years and decades68. Moreover, the relatively low-cost of establishing a video camera system eases the spatial development of this network whose maintenance depends almost only on human resources. The multiplicity of video camera system sites contributes to the strengthening of the database necessary to study the associated coastal physical phenomena.The video camera network described in this paper could lead to the implementation of a more integrated management policy along the African coasts. Video camera systems can provide valuable information with adequate temporal resolution and spatial coverageThe database generated from the African coastal camera network should serve as a basis for the study of human and natural processes , the prediction of associated risks, and therefore for the development of a common regional coastal management policy. This includes the identification of objectives, priorities, strategies, and timetables common to several countries to achieve them, even if compliance with legal and regulatory frameworks is a challenge that falls under the sovereignty of the States, with of course the consideration of United Nations guidelines at the level of the African Union. Thus, the ongoing data acquisition by video cameras could be a crucial backbone for coastal monitoring and management along the African coast.70. Algorithms to detect plastic waste or oil pollution from video-derived images in the nearshore could be developed and tested, for example in coastal areas where oil facilities are located. Monitoring of the sediment budget due to coastal infrastructure development is feasible using a similar approach to that used in the multi-platform data collection strategy deployed for a year at Elmina, Ghana69. Other local challenges, such as Sargassum beach landings74 are becoming an increasingly prevalent problem in the West African region (e.g. Ghana). Innovative video image processing algorithms could provide evidence of the spread of Sargassum in the nearshore.The African coastal camera network can be the basis for the development of monitoring systems specific to the sub-region concerning the management of, for example, the registration of the departure and arrival of artisanal fishing boats, which are essential in the region. More rigorous observations using video stations would likely provide a better understanding of the local dynamics of the Langue de Barbarie , which continues to undergo significant morphological changes following the opening of an artificial breachWACA Management Programme; or the ORLOA, an observatory established to develop the Central and West African coastal territories sustainably, through the promotion, production, and sharing of reliable and homogeneous data using harmonized data collection protocols for decision-making.The African coastal camera network has the potential to bridge the problem of non-data availability for coastal studies in Africa. The video data from the network can provide data and information that will help coastal scientists, investors, managers, and policymakers in improving the spatial planning and management of the African coastal areas. The network can be used to gather data that will be used for studies on flooding, erosion, coastal structures, infrastructure monitoring, oil pollution assessment, overfishing, and ecosystem and ecosystem services. Such a network should be linked to the World Bank-funded A video camera system consists of a hardware part  and a software part . Although video camera systems do not experience issues associated with in situ instrumentation , they are still subject to other types of malfunctions: air moisture very often causes electronic failures of the station and power failures often lead to a more or less prolonged downtime of the camera. In addition, video camera systems are limited to daytime observations and atmospheric conditions can affect image quality .75.To reduce the effects of air moisture, cameras fitted with memory cards have been installed in Saint Louis , Assouindé (Côte d’Ivoire), Dzita (Ghana), and Elmina (Ghana), instead of installing an on-site local computer as in Grand Popo (Benin), Mbour , Kribi (Cameroon) and James Town (Ghana). In Saint Louis , the video camera system is equipped with solar panels to compensate for power failures. The use of solar panels reduces gaps in data collection. The implementation of remote control system which is feasible when an internet connection is available would allow real-time monitoring essential for early warning systems. The effects of atmospheric conditions on image quality are compensated by applying image quality detection algorithms, such as the criterion based on the standard deviation of the pixel intensityORLOA could be used as a regional centralized repository accessible to researchers and decision makers. The repository should be made up of consistently data and processing algorithms, to promote sharing and integration. The network is poised to make significant progress on coastal environmental issues that have significant societal impacts. It is, therefore, essential to expand the video camera station coverage to other locations within Africa, especially the coastal sectors that have been characterized and identified based on their level of hazards and issues, or that are characterized by varying morphology and dynamics.The African coastal camera network is rapidly growing, and it is set to become an African data hub for coastal video imagery. The WACA/ORLOA), and local and international development partners are welcome to be part of the network. If this vision is achieved, coastal video camera imagery will transform environmental monitoring along the African coasts. It is the only way forward if we want sustainable African coasts.In the long-term, the video-derived data has considerable potential for use in other coastal environmental issues such as in the management of ecosystem protection, including competing coastal land uses , fisheries, and resource management, recreation, plastic and oil pollution monitoring, navigation, and coastal protection. Similarly, it has the potential of providing key information that can be used in basic input to the engineering design of the coastal zone, and support for integrated numerical model validation. And video-derived data can be coupled with other available data/platforms to provide even more observations. This should be strongly encouraged. However, strengthening the existing video camera systems and creating new ones requires more stable funding. The African and international coastal community, including academics, governments, regional  and morphologic  data collected by an increasing number of video camera systems. These data have led to new methodological developments, student capacity building, and a better understanding of coastal processes, e.g., tropical beach dynamics, sea level variability, dangerous rip currents or flash rips, and the impact of coastal defences.DGPS, unmanned aerial vehicles (UAVs), but also wave, tide and current moorings.The African coastal camera network can help investigate and address societal and environmental challenges . It can also provide key local ground truth that is important for satellite remote sensing techniques and engineering studies, even more, if when coupled with other measurements such as ORLOA) or the West Africa Coastal Areas Program (WACA) to target hotspots. This network needs to be perennialized and further extended to answer important questions related to coastal hazard hotspots and coastal zone development in Africa. The expansion of the video station network and additional efforts from all coastal planners and development stakeholders are required.The development efforts and lessons learned in each African country can be synergized, enabling more efficient planning through sharing of associated (novel) technologies, data analyses, and results. This network is a real asset for regional programs like the West African Coastal Observatory , James Town (Ghana), Mbour , and Kribi (Cameroon) video camera systems are fitted with an on-site local computer that processes the raw images and stores three types of secondary images every 10 or 15 min: snapshots, time exposures (timex), and time-stacks. Timex images are snapshot images averaged every 10 or 15 min into a single imageSaint Louis , Elmina (Ghana), Dzita (Ghana) and Assouindé (Côte d’Ivoire) video camera systems are not fitted with a local computer. The raw images collected at a frequency of 2 Hz are stored directly on a memory card as a video file since the new versions of the cameras used allow this. This implies that the data must be retrieved before the memory card is full.76 and radial distortion correction of the lens78. The image distortion induced by the curve of the lens is corrected using the internal parameters of the camera  which are calculated using the least squares error minimization method.The process of image rectification consists of determining the relationship between the original image pixels coordinates and the real world coordinates: latitude, longitude and elevation  add errors of a few metres to rectification error, in addition to uncertainties related to camera movements due to atmospheric conditions80.Overall, the average horizontal error due to image rectification varies from a few centimetres on the beach to a few metres offshoreTable Supplementary Information.


Expert sport performers cope with a multitude of visual information to achieve precise skill goals under time stress and pressure. For example, a major league baseball or cricket batter must read opponent variations in actions and ball flight paths to strike the ball in less than a second. Crowded playing schedules and training load restrictions to minimise injury have limited opportunity for field-based practice in sports. As a result, many sports organisations are exploring the use of virtual reality (VR) simulators. Whilst VR synthetic experiences can allow greater control of visual stimuli, immersion to create presence in an environment, and interaction with stimuli, compared to traditional video simulation, the underpinning mechanisms of how experts use visual information for anticipation have not been properly incorporated into its content design. In themes, this opinion article briefly explains the mechanisms underpinning expert visual anticipation, as well as its learning and transfer, with a view that this knowledge can better inform VR simulator content design. In each theme, examples are discussed for improved content design of VR simulators taking into consideration its advantages and limitations relative to video simulation techniques. Whilst sport is used as the exemplar, the points discussed have implications for skill learning in other domains, such as military and law enforcement. It is hoped that our paper will stimulate improved content design of VR simulators for future research and skill enhancement across several domains. While i Outlook  on this We define VR as cave automatic virtual environment (CAVE) or head-mounted displays (HMD), such as Oculus Quest, that fully immerse the user to create the presence of being in a different environment to the current location . These VThe beginning of Drew's  article The purpose of this brief opinion paper is to discuss what is currently known about expert pick-up of visual information for anticipation and how it can be trained, with a view that this knowledge can better inform VR simulator content design. Anticipation is defined as the capability to use visual  and non-visual  information to predict what will happen, before or early in an opponent’s action, and make a correct decision using verbal, button press, or motor responses . This paVideo or field-based temporal occlusion, where the time course of visual information is controlled through a black video frame or glasses that switch from clear to opaque, has been predominantly used to understand anticipation in sport . AlternaAs observed by Drew , some exVideo simulation of an opponent(s) movements have been displayed as points-of-light placed on anatomical landmarks with a black background or where the display has been blurred , 18. TheDrew  mentionsgroup-based comparisons, rather than individual differences within expert samples [Whilst the studies discussed above have been useful, they have focused upon  samples . Drew [2 samples  that rep samples . This in samples . MoreoveWhere possible, design of VR should incorporate nested individual comparisons for research and application in skill development. Due to the capability for body positional tracking in synthetic VR experiences, it is possible for anticipation outcomes such as response timing and response accuracy to be measured on a continuous scale. Whereas for video-based VR experiences, anticipation outcomes for response timing can still be measured on a continuous scale, with response accuracy on a dichotomous scale. This level of analysis in VR is valuable for three reasons. First, as competition skill level increases there is a smaller sample of genuine experts and it is challenging to recruit large samples for studies that include field-based assessments . AdequatThere continues to be debate regarding the contribution of perception and/or overt action coupling to anticipation skill . The litBased upon the above, VR simulator content design can incorporate verbal, button press, and/or motor responses to sports-specific perceptual information. This may be necessary for two reasons. First, a verbal or button press response will allow easy use of commercial video-based VR experiences that can be cost-efficient and re-create sports-specific information, but are not sufficiently advanced like more expensive synthetic experiences to measure perceptual-motor positional or accuracy responses at high sampling frequencies , 43. SecThe previously discussed content has considered the pick-up of early visual information for anticipation. Some field-based studies have also used spatial occlusion, which involves masked advance or object flight cues, with performance decrements relative to the unoccluded control condition indicating the importance of the masked (occluded) scene for anticipation . Using sTo target both predictive and prospective control, VR simulators can be designed where temporal occlusion is applied immediately after presentation of advances cues, but also during object flight. This would ensure that performers must attend to both early visual information that maps onto gross body positioning and later visual information that maps onto fine-tuning of action . SynthetA variety of instructional approaches have been used to improve anticipation skill. These include; temporal occlusion with an unoccluded replay , 51, verThe points discussed in previous sections need to be taken into consideration when designing VR simulators for learning and transfer. Whilst considerable work still needs to be done to determine whether VR training improves performance and facilitates transfer, there is no reason to suggest that the instructional approaches validated through video simulation will not be at least of equal value in the VR medium. In terms of synthetic VR simulators, there is greater control over the manipulation of stimuli relative to action responses and selective presentation of correct or false feedback, than in video-based VR. Whether these benefits indeed lead to greater learning and transfer of anticipation than video-based VR and video-based simulation is yet to be established. Further, there are current challenges in creating accurate synthetic models of opponent kinematic cues (see Sect. Whether video-based VR compared to video-based simulation leads to superior learning and transfer of anticipation also remains to be confirmed. For example, a recent study by Fortes et al.  comparedDue to the reasons mentioned above, careful consideration needs to be given as to whether and how video and VR simulation should be compared and used. It may well be that both could be used within their scope to improve the anticipatory skill of athletes in different sports, with different levels of development or competition, and with different deficiencies to address. For example, to improve athletes’ capabilities to pick up contextual and kinematic advance cues, video-based simulation or video-based VR could be used, while to improve athletes’ pick-up of early object flight to fine-tune motor responses, synthetic VR could be used. Alternatively, in a single VR simulator, contextual and kinematic advance cues could be presented via video simulation, whilst object flight is synthetically simulated .VR simulators are widely used for assessment and training of skill in sport and other domains , 4. Neve


In recent years, the ENEA has introduced a novel methodology based on motion magnification (MM) into the Italian cultural heritage protection and monitoring field. It consists of a digital video signal processing technique able to amplify enormously the tiny movements recorded in conventional videos, while preserving the general topology of the acquired frames. Though the idea of such a methodology is not new, it has recently been provided with an efficient algorithm that makes possible a viable and low-cost magnification. Applications are extremely varied in almost every field of science and technology; however, we are interested in its application to the safeguarding of architectural heritage, a sector of the utmost importance for Italy. As ancient buildings can be extremely sensitive to even minimally invasive instrumentation, most common monitoring sensors can be replaced by contactless tools and methods, such as video-based techniques like MM. It offers many advantages: easy to use, contactless devices, virtual sensors, reusability of the videos, practicality, intuitive graphical results, quantitative analyses capability and low costs. These characteristics are well suited to the monitoring of large ancient monuments; on the other hand, historical sites have peculiarities of their own, requiring careful approaches, proper tools and trained personnel. Moreover, outdoor applications of MM present quite notable difficulties from a practical point of view, e.g., the dimensions of the studied objects, uncontrolled environmental conditions, spurious vibrations, lighting change/instability, etc. Here we give a general idea of the potential of MM and related issues, using some relevant in-the-field case studies in Italian heritage protection. Video-based monitoring methods offer a unique property: each pixel of a frame can be considered as a virtual sensor, which is like having a very high sensor density on the studied object surface. Another remarkable property of video-based methods is that data are acquired from a distance. This implies that hardly reachable points of non-movable objects can be analyzed as a valuable alternative to placing sensors on their surface. However, there are some movable objects that are particularly vulnerable or delicate, such as archaeological artifacts and works of art. In such circumstances, video-based methods provide a contactless solution, which guarantees the maximum respect for the preservation of the studied object. Moreover, processing techniques can be focused on specific regions-of-interest (ROIs), which means limiting the analyses to selecting the most convenient pixels instead of analyzing the whole image comprising millions of pixels. Furthermore, this allows changing the choice to a more suitable area or the selection of more useful pixels if a different analysis of the video recording is required at a subsequent time.All the above could be applied also to the study of vibrations, which essentially are tiny motions of the studied object. A major issue for video-based analysis of vibrations is that tiny movements embedded in a conventional digital video generally require a relevant amplification of the pixel time series in order to visualize the vibration. However, such amplification should preserve the general topology of the object in the frames. After many attempts to find an effective algorithm to solve this problem, a research group at MIT finally succeeded , providiNevertheless, researchers are very interested in assessing the method’s feasibility, since conventional devices are surely more precise but are also expensive and much less practical. Therefore, MM can be useful in a large number of scientific fields, and nowadays there are even hardware tools available for performing the MM elaborations almost in real-time, although the cost of these devices is quite high. Today, the effectiveness of visual methods in the industrial environment, physics, biology and engineering is established. A number of experiments conducted on simple geometries like rods and other small objects have demonstrated the reliability of this methodology inside a laboratory, compared to contact accelerometers and laser vibrometers ,7. Of coIn the following, a review of recent studies conducted on cultural heritage assets in Italy using the MM method are presented and discussed. They were carried out to monitor and analyze structures and objects both qualitatively and quantitatively. This review also provides the elements to illustrate the potential of this innovative methodology. Such studies were carried out in the framework of approved research projects or on request by the site manager in order to explore the potential of this innovative method. The presented case studies were not selected on the basis of specific criteria other than the assumption that object vibration can be caught and analyzed by video recordings if the camera resolution, pixel dynamic range and speed used are sufficiently high in relation to the intensity and stability of lighting conditions. In addition, the challenge was to explore the possibility of providing valuable indications even with common commercial low-cost cameras.First, some laboratory experiments using shaking table tests to validate the methodology are presented. Then, several in-the-field case studies related to some important Italian monuments will be described. In particular, studies on the Ponte delle Torri of Spoleto and several monuments in Rome  are illustrated.In the case studies presented in this review, the Eulerian and the phase-based versions of the MM algorithm were implemented to process the videos. Subsequently, the magnified videos were subjected to further processing steps to analyze the frequency content of the signals or to extract a normalized relative displacement map of the studied objects. In fact, the main aim was to provide a rough estimate of the modal frequencies and of the relative displacements related to the deformed configuration , which are widely used to monitor the structural health of cultural heritage structures . HoweverAs for the Eulerian version of the MM algorithm, the main equation for the direction x (in a video with frame coordinates x and y) is the following :∆I = f in the video acquisition, can be detected. Nonetheless, it is strongly suggested to adopt a wide oversampling of data, in the order of many times  the maximum frequency of interest. This is certainly true also in the case of the MM method. To be more explicit, considering a common low-cost camera with typical values of frame rate around 24–30 fps, a rough estimate of the frequencies can be realistically achieved below 5–6 Hz and particularly interesting results can be obtained below 2–3 Hz. This means that a commercial low-cost camera is potentially capable of identifying the first modal frequency of a large building or monument, whose main frequencies are typically below 2–3 Hz, but unsuitable for smaller objects, such as museum exhibits that typically vibrate at higher frequencies. In these cases, the use of a high-speed camera can be indispensable.In summary, the main parameters to be set are the frequency range and the amplification factor. They are specified in the details found in a short manual enclosed with the MIT software . HoweverIn this section, a collection of the most relevant laboratory cases carried out in Italy for the validation of MM application to cultural heritage assets is illustrated. In particular, the laboratory tests here illustrated were performed at the seismic hall facility at the ENEA Casaccia Research Centre , which iEncouraging results were obtained in a shaking table test experiment for a typical Italian historic masonry stone wall . In thisSignals from the markers provided the reference benchmarks for the comparison with the MM. It is also to be noted that usually the presence of edges or texture is helpful for the MM. Unfortunately, the ROIs in this case are rather homogeneous, which causes a quite high signal noise. Signals from the magnified motion technique do not provide directly the displacements, although they could be recovered by means of the constant contours method. On the other hand, they may be used to calculate the Power Spectral Density (PSD) or the Fast Fourier Transform (FFT), allowing the modal analysis and the calculation of the FRF. Hence, the 3DVision system is a convenient reference to evaluate the MM performance in the frequency domain. The FRF was calculated using both the 3DVision markers and the MM signals from the selected ROIs.In More recently, a series of similar shaking table tests was performed on historic masonry walls in unreinforced and reinforced conditions with several retrofitting techniques . The acqMore complex structural portions of historic buildings were also tested. The mock-up of Before and after each earthquake motion test, the mock-up is excited with extremely low-intensity pseudo-white-noise vibration (random test) for dynamic identification of the structure. In random tests, the MM elaboration may enhance the deformations of the tested mock-up before much stronger vibration tests cause damage to the structure.The video resolution was only 640 × 480. Nonetheless, the magnified video results were extremely effective in visualizing the dynamic behavior of the drum, especially in terms of modal shapes and frequencies identification. This was achieved by taking videos at 60 fps, which confirms the importance of video speed, allowing large oversampling with respect to common 20–30 fps cameras. In particular, the MM analysis was limited to the first modes (below 10 Hz), which usually are the most important in terms of mass participation, providing indications of the global behavior of the overall structure.The so-called Temple of Minerva Medica is located between the railway tracks and a tramway in the center of Rome see a, near TAfter several partial collapses and restoration interventions in the past, the size of the main hall is today almost unchanged, except for the height, which is currently slightly reduced. During the period 2016–2018, extensive monitoring campaigns were performed, combining vibration monitoring, 3D geometric laser scanning, thermal infrared and microclimatic acquisitions ,17,18.In this application the basic idea of the MM quantitative analysis was to take advantage of the large number of pixels contained in a frame. Theoretically, a large number of “virtual sensors”, corresponding to the number of pixels within the acquired frame, can provide a time history of intensity variation, color or grey scale. These time series contain information about the displacements of the physical points related to the pixels. Of course, not every surface of the structure generates useful information. In addition, processing all pixels of the studied object might result in a huge number of pixels requiring excessive computational time. Therefore, it is more convenient to choose a smaller ROI having the highest SNR. The identification of an efficient ROI is a crucial point in the MM procedure. However, in this case study, the authors did not use the SNR criterion; rather, an ROI containing the corner of a niche providing maximum color edge was chosen for the MM processing , Enhanced Frequency Domain Decomposition (EFDD) and Stochastic Subspace Identification (SSI) were utilized. EFDD provides also an estimation of modal damping, while SSI is a more sophisticated and automatic procedure based on time-domain approach . The aveTo understand why the MM method appears less accurate for the Ponte delle Torri, one should take into account the adverse environmental conditions, which prevented a correct recording angle for the camera, the distance from the target, the absence of suitable edges and, of course, the weak vibration sources. This last point seems to have been the decisive factor. MM is able to amplify sufficiently even the micro-displacements caused by the wind, but the signal-to-noise ratio remains low if the vibration sources are weak, and further increasing the amplification factor would produce many artifacts in the magnified video. In other words, the displacements are recovered, but amid a high noise level that seriously affects the MM-PSD elaborations. For more details on this case study, see .The Crypta Balbi was the theatre of Lucius Cornelius Balbus (13 BC), which included a vast hall  and an exedra on the opposite side a. The maIt is well known how historical monuments in the urban environment are severely affected by anthropic vibrations, air pollution and other aggressive agents; therefore, the health monitoring of those structures is essential to preserve the sites. If the monument to be monitored is large, extended and includes many minor parts, it is not feasible to use a sensor for each studied element. On the other hand, video-based methods can provide both a global view and also a detailed local analysis when needed. In such a context, MM was tested for this purpose, obtaining interesting results.In The mapping of the maximum displacements of the wall magnified in the frequency range 0.5–1.5 Hz a helped Another important advantage of using video-based methods for investigating cultural heritage is the potential to examine areas of the structure that would be otherwise very difficult to reach physically without putting the operator’s safety at risk, not to mention the possibility of contactless investigation of the monuments ,26,27. AThe analysis of the relative normalized displacement pattern helped identify the most deformable areas, which provided interesting indications about the stability of the pattern of the frescoes’ plaster layers , as wellThe most famous monument of Rome is located in the city center where underground subway lines, tramways and road vehicles are sources of relevant vibrations. Video shooting was carried out using a commercial camera, at a low frame rate (28 fps) and positioned at the considerable distance of about 100 m from the monument.In The video was magnified at frequencies from 1 Hz to 5 Hz, corresponding to the main modes described in the literature ,29. VisuThe amplification factor was set to a quite high level  because of the considerable distance from the studied object. Nonetheless, the good lighting conditions (stable and sunny conditions) made it possible to avoid excessively disturbing noise and distortions in the MM analyses. Furthermore, concentrating the MM analyses on very low frequencies in relation to the frame rate (corresponding to an oversampling of up to around 20 times the frequency of interest) helped the quality of the results.The complexity of the pixels’ signals was analyzed in terms of image entropy, which provided, as expected, remarkably high values along the structural edges c, confirvilla suburbana (country house) of the Quintili represents one of the largest Roman villas ever discovered  and being able to acquire the video from a good point of view and a relatively short distance.The obtained image entropy map c enhanceAs was the case also with the so-called Minerva Medica temple, the National Etruscan Museum is located in the city center of Rome, close to tramways and trains whose vibrations represent a serious threat to the artworks preserved in the museum. In particular, one of the most important showpieces of the museum is surely the famous Sarcophagus of the Spouses , a masteMore specifically, the statue lies on a wooden-covered support whose structure is constituted by a shallow metal bedstead-like frame. The dynamic behavior of this support was also characterized to understand its impact on the overall Sarcophagus. According to experts, the feet could be one of the most vulnerable parts. Indeed, this was confirmed by preliminary analysis which revealed two anomalous peaks in the frequency domain, as shown in Some distinctive features of MM in outdoor environments and being applied to cultural heritage came up during the fieldwork carried out in recent years. In some cases, the imperative necessity to preserve a precious or vulnerable object can be a limitation even for contactless investigation technologies. A good example is the Sarcophagus of the Spouses, where the display cabinet glass lighting reflections were very disturbing for the video recording quality. The use of available low-cost and quality instrumentation, instrumentation vibration isolation, the effects of lighting conditions, etc., caused further specific issues for video recording quality, which required careful attention when designing proper monitoring systems. In some circumstances, the monument location, size and geometry can make it difficult to record videos from an optimal point of view or distance, and with proper ambient lighting conditions, when both artificial and natural light are feeble and indoor space is rather limited. The amplification factor, determining how enlarged the motions in the video are, remains crucial and thus it must be carefully selected in order to obtain good results. Unfortunately, there is still no exact procedure for a fine tuning of the amplification factor and it is currently based on operator experience. However, some simple rules of thumb may be offered. If the original video is of good quality, meaning that the video has been made with a high frame-rate camera under bright and stable lighting, and no disturbing shadows or large movements are present, then the amplification can be enlarged to quite high levels until typical distortions, similar to a disturbing haze, appear in the magnified video. On the other hand, the geometrical acquisition configuration also plays a relevant role, as is usual in video-based techniques, as well as the intensity of the vibration that excites the studied object. Briefly, if the signal-to-noise ratio is favorable, i.e., the ambient vibration induces quite ample oscillations in relation to the camera distance and angle, usually the amplification can be raised. Otherwise, particular care must be taken to prevent noise. In the case of the Colosseum, the underground subway transferred strong vibrations to the monument as well as to the camera, adding significant disturbances to the magnified videos. Thus, a complete standardization of the analysis procedures is a hard task. However, it is worth noting that, unlike most common industrial and engineering applications, vibration monitoring for cultural heritage requires less stringent constraints in standardized measurements; therefore, the trade-off between the precision/accuracy and the instrumentation’s ease of use is actually favorable to MM. At the same time, the huge number of contactless measurements available from digital video-based methods like MM finally results in an extreme flexibility not easily available with the other, more accurate techniques. Moreover, video-based technologies are very promising in terms of their development in the near future, so that the availability of more real-time and easy-to-use hardware systems, able to fix the current signal noise issues and enabling a more intensive use of MM, is likely, overcoming the most common current limitations. Consequently, the already interesting performance in the recent experiments presented here demonstrates that relevant developments in the near future have real potential to produce breakthroughs in the field.It is also worth noting that up to now, only relatively few researchers have been dedicated to the development of the MM methodology, and in particular to the development of its application to the study of cultural heritage assets. This is true also in Italy, where the protection of culture heritage is of utmost relevance. Considering all of the above, the increasing interest in this technique will predictably see a fast acceleration in the spread of applications in this field, triggering a virtuous cycle promoting further advances and experiences.


Click chemistry reactions constitute an important and relatively new approach in the medicinal chemistry toolbox and offer substantial advantages to medicinal chemists in terms of overcoming the limitations of facile chemical synthesis, increased throughput, yields and improved quality of compound libraries. Over the last two decades, click chemistry has been widely used in different aspects of carbonic anhydrase  modulators drug design. This review provides an overview of the general principles and applications of click chemistry in CA-related research, including the design of selective CA inhibitors (CAIs), their applications against several diseases such as innovative anticancer and anti-infective agents, fluorescent and radiopharmaceutical probes as new theranostic agents, as well as their application in protein labelling. These12–14, 12–14) exhibited good selectivity against the tumour-related hCA XII. For this reason, the authors investigated their binding mode by molecular docking studies, showing the benzenesulfonamide moiety to accommodate into the active catalytic pocket towards the zinc ion and the triazole tail displaying a binding towards the rim of the hCA IX and hCA XII active sitesManzoor et al. employed the click tail approach in the design and synthesis of new CAIs bearing substituted pyrimidine rings through a linker incorporated for enhancing the flexibility and achieving more interactions at the rim of CA active site, in order to produce selective CAIs 12–14, 25. This N‐triazolo‐benzene sulphonamides‐1,5‐benzodiazepines 15, 16  over the cytosolic isoforms hCA I and II.The click tail approach was not employed only to modulate the selectivity of sulphonamide derivatives but, more recently, has been applied to novel chemotypes associated with the inhibition of CAs such as coumarins, a class of compounds that first showed high selectivity mainly for the tumour-associated isoforms hCA IX and XII,17 by using the Sandmeyer reaction and subsequently reacting it with a series of alkynes, a series of 4-substituted-1,2,3-triazoles were obtained, in the presence of copper-based catalysts, as shown in Scheme 1Sulfocoumarins  are one of the ultimately discovered prodrug-type class of compounds acting as selective inhibitors against different CA isoformscis) and 1,4-(trans) triazoles has been reported, which had to be separated, and only in two examples (with 3-F and 3-Cl substituents) the desired product was observed to be formed in superior amount compared to the thermal cycloadditioni in the high micromolar range (up to more than 10 µM). On the other hand, all compounds showed effective inhibition affinity against the tumour-associated isoforms hCA IX and XII, with inhibition constants in the low nanomolar range (Ki 7 to 90 nM). In particular, compounds with 5-substituted-1,2,3-triazoles proved to be highly isoform-selective inhibitors, identifying them as suitable drug candidates for clinical trials. The employment of click chemistry on the sulfocoumarin scaffold was continued, in 2015 by Nocentini et al. since substituents at the 7 position were not reported in previous studies (2O linker showed high selectivity against the tumour-associated isoforms hCA IX and XII (Ki spanning between 4.5 to 26.8 nM). Interestingly, substituents in position 7 were observed, as in the previous work, to be effective hCA II inhibitors and ineffective hCA IX and XII modulatorsMoreover, the same authors explored the possibility to use ruthenium-based catalysts, instead of copper, to achieve the less explored 5-substituted-1,2,3-triazole sulfocumarins . Indeed, studies 37. The ain vivo, Moeker et al.18–20,,Considering the opportunity to selectively targeting the extracellular hCA IX and XII 20) compared to the classically sulphonamide inhibitor acetazolamide, and proved to be good candidates for being investigated as antitumor agents.All compounds displayed highly selective inhibition for hCA IX over hCA II, increasing the isoform specificity at least 22-fold for hCA IX (21) through a multistep procedure. In the next step, the authors generated five different peracetylated mono or disaccharides  to which double bonds were appended as the ene component, and reacted them with thiol 21, to generate the desired thioethers  as well as in the virulence of many bacterial, fungal and protozoan pathogens and, several literature data have shown that their inhibition impairs parasite growth and virulenceMycobacterium tuberculosis, Vibrio cholerae) have been included in the study with both α- and β- class CAs being tested. β-mtCA3 from M. tuberculosis and two such enzymes (VchCAα and β) from the second one allowed the possibility to discover selective inhibitors, possibly of interest to be investigated for the management of infections provoked by these pathogens. Among them, the first subset of derivatives showed high affinity for VchCAα with inhibition constants in the low nanomolar range (KIs between 0.72 and 22.6 nM). On the other hand, compounds of the second subset preferentially inhibited VchCAβ with KIs in the range of 54.8–102.4 nM, whereas β-mtCA3 was inhibited with KIs in the range of 28.2–192.5 nMDifferent bacteria species possessing CAs  has been functionalised with both the alkyne or azide group and via Huisgen’s 1,3-dipolar cycloaddition  was reacted with the coumarin counterpart.The fact that hCA IX overexpression has pivotal role in cancer and its expression is rather restricted to malignant cells, offers an opportunity to develop targeted therapies in the oncological fieldAll compounds are evaluated under normoxic and anoxic conditions against different cell lines such as MRC-5 , HCT-116 , MDA-MB-231 , and HT-29 , but without any data regarding the binding affinity against hCA IX. From the reported data, the target compounds exhibited good activity against the HT-29 cell line under hypoxic conditions displaying one- to 10-fold greater activity as under normoxic conditionMore recently, Berrino et al. reported CAI hybrids incorporating the azidothymidine (AZT) scaffold, a telomerase inhibitor, by using the CuAAC reaction, and obtaining a large library of derivatives bearing primary sulphonamide, coumarin and sulfocoumarin moieties 52.Several such compounds showed low nanomolar CA IX/XII inhibition and potent antitelomerase activity in PC-3 and HT-29 cell lines, giving the first background to develop CAI-telomerase inhibitors as promising antitumor agents.,As mentioned above, the opportunity for the selective targeting of the extracellular hCA IX and XII has been extensively investigated in the last two decades, also by using the click tailing approach for obtaining glycoconjugates, which due to their polar nature possess limited passive membrane permeability, enabling them to specifically bind extracellular CAs50 values >1500 mg/kgChu et al. applied the same sugar-tail approach by using Huisgen’s 1,3-dipolar cycloaddition with a more selective CAI chemotype, i.e. the coumarin scaffold, for targeting hCA IX and XII23), as shown in The click chemistry was also employed to develop novel delivery systems targeting hCA IX, for enhancing therapeutic efficacy of the cytotoxic agents such as paclitaxel (PTX). Tatiparti et al. used human serum albumin (HSA) as delivery system due to the fact that it presents several opportunities for covalent modification, has a low-cost, is non-immunogenic and naturally biodegradable, making it an interesting starting point for incorporating a well-known anti-cancer agent such as paclitaxel (PTX)Subsequently, the authors carried out several studies to investigate the presence of all components used to form the delivery system such as FTIR for confirming the formation of the triazole ring, HPLC and UV spectrophotometry to check paclitaxel payload of around 11.3% w/w and the particle size. These functionalised nanoparticles wre assayed on two different cell lines overexpressing hCA IX, MDA-MB-231 and MDA-MB-468. The results showed a dose-dependent killing and also a cell viability much lower than the non-targeted preparation. In addition, hypoxic conditions increased the uptake of the formulation and enhanced efficacy in the MDA-MB-468 cell linein vivo study, in order to investigate the penetration ability of the nanoparticles in the tumour core. The obtained data showed that the hCA IX targeting oligomer efficiently reached the core of the tumour spheroid, and, when co-administered with sorafenib had a superior tumour accumulation compared to the accumulation in liver, demonstrating effective antitumor response in A498 tumourshCA IX is an excellent biomarker of hypoxic tumours such as renal cell carcinoma (RCC) and, in this context, Alsaab et al. employed functionalised nanoparticles to target hCA IX in a targeted polypharmacological payload delivery against RCC cells6.in situ click chemistry, assembling different azides (containing fluorine fragments) with an acetylene sulphonamide (as an anchor molecule), identifying the compound with the best affinity for hCA II. The screening was performed in microtiter plates by incubating binary mixtures of anchor molecule and azides[19F] and hCA II in phosphate buffered saline (PBS) at 37 °C for 36 h. Among the azide moieties, the 4-fluoro-2-aminomethyl one showed the highest binding affinity with a Kd of 0.5 nM, and led the authors to synthetised on a preparative scale compound 24 using CuI as catalyst for the CuAAC reaction and subsequently labelled it with the isotope [18F] in good yields, using the 4-nitropyridine precursor . Since the last review on click reactions applied to the synthesis of CAIs, published in 2010recursor  accessib24 has been obtained in 15% yield with a radiochemical purity of 99.4%, as determined by radio-HPLC analysis and the time employed for the total process was 64 min, which is approximately 50% of one 18F half-life (t1/2 = 110 min), with a specific activity of the tracer from 1 to 2 Ci µmole−124 showed that it was mainly accumulating in the blood, lungs, heart and kidneys with lower amounts of radioactivity founded in the stomach, muscle, brain and bone, in agreement with the known hCA II expression and distribution in these tissues,24 is not suitable for neurological imaging applications.Derivative 18F to labelled CA inhibitors was used six years later (2019) by Jia et al. with a less investigated class of inhibitors, the peptides18F-scaffold was synthetised in order to obtain, by click 1,3-dipolar cycloaddition, the labelled 18F-peptide 25 in an overall radiochemical yield of 35–45% and >99% radiochemical purity as reported in The employment of the radioisotope The novel radiochemical tracer showed good stability after 3 h at 37 °C in PBS. On the other hand, it was readily degraded in new-born calf serum (NBCS) after 3 h. PET imaging displayed clearly the tumour area with a heterogeneous intratumoral distribution and small amount of radioactivity entering also in the brain. The high expression of hCA IX induced by hypoxia in the outer core of the tumour was totally in agreement with the images reported by the authors68Ga-labelled acetazolamide derivatives divided in two series26–31 in an overall yield of 32% and 37%, respectively. At the same time, the authors prepared three cyanobenzothiazole (CBT) derivatives labelled with 68Ga and conjugated with acetazolamide derivatives 26–31 via an orthogonal CBT/1,2-aminothiol click reaction as highlighted in Chen et al. developed, in a two-step orthogonal labelling method, a library of six ,The efficiency of the click reaction was first tested at pH 7.4 demonstrating different reaction kinetics among the reported derivatives, presumably affected by the differences of chemical structures, configurations and electronic distribution32) yields a red fluorescent bands, on the other hand, the non-specific probe (33) predominantly react with off-target proteins to give green bands (32) was used by itself, hCA II could be detected only at a higher abundance (>5% w/w).The bioorthogonal click reactions are largely used over the last decade to synthesise fluorescent probes employed into the photoaffinity labelling (PAL), as a tool for target identification and to reduce the false-positive detection of abundant non-specific proteins. In this context, Sakurai et al. reported the development of a new dual-PAL strategy, where co-reaction of active/inactive probes bearing orthogonal fluorescent groups provided selective crosslinking and straightforward detection of specific-binding proteinsen bands . This coThe fluorescent moiety could preinstall as a part of the probe structure or introduced by an excellent alkyne/azide-reactive fluorescent reaction through click chemistry after the PAL reaction. However, high concentration (>100 µM) of inactive probe is needed to block non-specific proteins and a ratio of 5:1 with active probe is needed to show the best activity with a discrimination factors greater than 1035) or branched (37) one, were synthesised in two different ways. The linear PAL probes were synthesised through sequential amide coupling reactions starting from the 4,4′-diaminobenzophenone scaffold (34). On the other hand, the branched PAL probes were synthesised from a Boc-L-propargylglycine (36) with a panel of different amino benzenesulfonamides as outlined in The development of PAL probes targeting CAs were investigated by Poulsen’s group in 2017, by incorporating a wide selection of primary sulphonamides possessing different structural features, a linker group as well as linear and branched arrangements of the probe components for selective detection of hCA II35 a SI for hCA II of 2.58 fold over BSA and 22.0 fold over OVA. Unfortunately, it resulted only in a faint hCA II band in all PAL experiments. However, the most favourable hCA II selectivity was achieved with the branched probe 37 with a SI of 20.0 fold against BSA and 33.8 fold over OVA and showed a strong hCA II-selective band. Interestingly, the results reported in the PAL experiments did not directly correlate with the affinity for hCA II as shown by the IC50 values reported in the work, as derivative 37 has a moderate affinity for hCA II. For this reason, the authors investigated the PAL probe–protein binding, protein crosslinking efficiency, and CuAAC efficiency by native state mass spectrometry and in-gel fluorescence showing for all probes a moderate binding formation with hCA II as in the case of complex [hCAII:37] where a substantial portion of 37 binding to hCA II active site but not crosslinking with CA II on exposure to UV, thus suggesting that the probe architecture might significantly affect the binding and crosslinking efficiency to the hCA II active site. Additionally, correlation of in-gel fluorescence and the crosslinking efficiency determined by MS analysis was not straightforward, as probe 35 generated only a faint fluorescence despite showing the highest crosslinking yield, whereas the branched probe 37, which showed >4.5-fold lower crosslinking yields than probe 35, gave moderate fluorescence intensity, probably due to the different accessibility to the biorthogonal reaction in the complex protein-bound probe. Thus, the conformational flexibility of the probe has been suggested to be a critical feature that can impact both target-selective binding as well as non-specific labelling, crosslinking efficiency and CuAAC reaction efficiency.As in the experiments to Sakurai’s group, previously discussed, selectivity towards the labelling of hCA II in the presence of excess non-specific proteins  in a total concentration of 4.3%, w/w of hCA II has been observed. From the general point of view, all linear probes showed strong non-specific labelling of BSA and weak non-specific labelling of OVA demonstrating that linear structures have a greater tendency to undergo non-specific labelling than probes with a branched structure, attributed to the relative flexibility of the former probe design38 with recombinant CA IX in aqueous buffer at pH 7.4 and illuminated it at 365 nm, observing a good fluorescent band at 55 kDa, fully compatible with recombinant CA IX. The next step was the employment of compound 38 in a more complex system as “Triple negative” breast cancer cells, MDA-MB-231, since are well-known to overexpress CA IXZhao and Burgess in 2018 synthesised trough CuAAC reaction, a CAI for targeting the tumour-associated isoform IX for PAL experiments, as reported in Scheme 12In the last years, Sakurai groups continued to study the employment of CAI in PAL with gold-nanoparticle-based probes to enhance protein binding and labelling efficiency41) was achieved by one step straightforward click reaction among a strained alkyne bearing a sulphonamide moiety (39) with a cyclopentadienone derivative (40) without any catalyst as highlighted in Bioorthogonal chemistry was not exclusively employed in PAL technology for the synthesis of fluorescent CAIs. Ji et al reported the development of bioorthogonally activated smart probes, where the florescence is “turned on” upon the click reaction between the two used reagents, thus making the tedious washing steps involved in biomolecules tagging unnecessaryThis smart probe was employed to selective label in two step the hCA II isoform in Hela cells showed strong blue fluorescence. In addition, the authors to confirm that the blue florescence was mainly the result of the smart probe bounded to hCA II, the Hela cells are pre-treated with a non-fluorescence CAI followed by the incubation with the probe showing a significantly decrement of blue fluorescence intensity compared to the cell treated with only the fluorescent probe confirming the selectivity of the target42 and driving the formation of a prevalent diasteoisomer compared to the other one (Z/E: 89:11)  , which w42a and 42 b) showed a different affinity, confirming that product 42a is the more potent inhibitor of bCA II (0.33 µM) and the possibility of using thiol-yne click chemistry as protein-directed synthesis of ligands. Finally, for compound 42 it was observed an enhancement of fluorescence only with bCA II indicating the probe specificity for bCA-II binding siteThe biological activity of two diastereoisomers  with a 1,2,3-triazolyl moiety (45) showed a 3-fold increase of the phosphate buffer (pH 7.4) solubility (from 1.2 mg/mL to 3.8 mg/mL) and for this reason derivative 45 was crystallised complexed with hCA II. It showed for the tail portion a very different orientation compared to structurally similar compounds devoid of the triazole moiety reported by Alterio et al. , four (49), and six (50) xanthate moieties mainly showed inhibitory activity against hCA I. Also in this case, the platform showed significantly stronger inhibition compatred to the monomeric species, but no strong multivalent effect was observedXanthates are well known to be not very stable compounds, as they are sensitive to acidic pH, high temperature, humidity and time, being hydrolysed to the starting alcohol and CS51, 54) and linear  peptides conjugated with multiple sulphonamide moieties under mild conditions and in high yields using metal-free click-type bioconjugation methodologies such as hydrazone and oxime ligations, as depicted in Figure 13Winum’s group, in 2017, synthesised cyclic From the inhiibtion assay, it has been observed that the multivalent oxime conjugates ,,a,,,This review describes the last 10 years of click chemistry as a useful and versatile synthetic tool, widely applicable for the development of novel CAIs, as well as their pharmacological applications. Click reactions are easy to perform under ambient conditions, give high reaction yields, have a good regiospecificity, and are tolerant to standard biological conditions, identifying the role of 1,3-dipolar click cycloaddition of alkynes and azides as the gold standard reaction to generate compound libraries and accelerating the process of finding and optimising lead candidates in all CAI classes. These reactions led many research groups to develop potent CAIs and afforded the possibility to modulate their selectivity towards various isoforms of pharmacological interest. However, the introduction of copper species into biosystems and living organisms raises the issue of potential toxicity, and thus, in the last years, the strain-promoted cycloadditions of cyclic alkenes and alkynes has established themselves as powerful alternative tools in bioconjugations. This review thus provides a general overview on the diversity of click chemistry developments in the CA field, which provided an important chemical strategy useful for different applications involving CA modulators. However as seen in the article, the click chemistry was mainly employed to develop CA IX/XII inhibitors, useful as anticancer agents and diagnostic tools,The antiinfectives based on CAIs started to be seriously considered only in the last decade