Proctocolectomy with ileal pouch-anal anastomosis is the intervention of choice for ulcerative colitis and familial adenomatous polyposis requiring surgery. However high-grade dysplasia and cancer in the anal transitional zone and ileal pouch after 20 years is estimated to be 2 to 4.5% and 3 to 10% in ulcerative colitis and familial polyposis, respectively. The risk factors for ulcerative colitis are the presence of pre-operative dysplasia or cancer, disease duration > 10 years and severe villous atrophy. For familial polyposis, the risk factors are the number of pre-operative polyps > 1000, surgery with stapled anastomosis and the duration of follow-up. Even if anal transitional zone and ileal pouch cancers seldom occur following proctectomy for ulcerative colitis and familial adenomatous polyposis, the high mortality rate associated with this complication warrants close endoscopic monitoring, mainly every year with pouchoscopy including chromoendoscopy.Proctocolectomy with ileal pouch-anal anastomosis is the intervention of choice for ulcerative colitis and familial adenomatous polyposis requiring surgery. One of the long-term complications is pouch cancer, having a poor prognosis. The risk of high-grade dysplasia and cancer in the anal transitional zone and ileal pouch after 20 years is estimated to be 2 to 4.5% and 3 to 10% in ulcerative colitis and familial polyposis, respectively. The risk factors for ulcerative colitis are the presence of pre-operative dysplasia or cancer, disease duration > 10 years and severe villous atrophy. For familial polyposis, the risk factors are the number of pre-operative polyps > 1000, surgery with stapled anastomosis and the duration of follow-up. In the case of ulcerative colitis, a pouchoscopy should be performed annually if one of the following is present: dysplasia and cancer at surgery, primary sclerosing cholangitis, villous atrophy and active pouchitis (every 5 years without any of these factors). In the case of familial polyposis, endoscopy is recommended every year including chromoendoscopy. Even if anal transitional zone and ileal pouch cancers seldom occur following proctectomy for ulcerative colitis and familial adenomatous polyposis, the high mortality rate associated with this complication warrants endoscopic monitoring. Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis (IPAA) is the intervention of choice for familial adenomatous polyposis (FAP) and ulcerative colitis (UC) requiring surgery . UC is cRPC consists of the removal of the rectum and the colon and the construction of an ileal pouch (reservoir formed with the last 40 cm of the ileum) followed by IPAA . This suThe main complications reported can be divided into short-term (within 1 month after surgery) and long-term complications . Short-tIleoanal anastomosis is the critical part of the surgery. Two anastomotic techniques have been described, namely double-stapled or hand-sewn anastomosis  15]. Ma. Ma15]. The epidemiology of these diseases implies that some patients undergo surgery at a young age. Balancing functional results and the risk of cancer in the ATZ and ileal pouch after surgery poses a real management challenge. Indeed, the rate of dysplasia of the ATZ after RPC for UC was estimated as 1.13% in a recent meta-analysis . TsunodaThe aim of this review is to report on the available data for dysplasia and cancer of the ATZ and pouch focusing on incidence, risk factors, the impact of surgery, in particular, and the initial pathology. This review will also outline the mechanisms leading to dysplasia, including the role of inflammation in the process of carcinogenesis and interactions between mucosa. Finally, we propose an algorithm for post-IPAA endoscopic monitoring.A PubMed literature search for “pouch dysplasia”,” pouch cancer”, “pouch neoplasia”, “anal transitional zone dysplasia”, “anal transitional zone cancer”, “anal transitional zone neoplasia”, “ulcerative colitis”, “familial adenomatous polyposis”, “restorative proctocolectomy,” “ileoanal anastomosis” and “ileal pouches” was conducted. Two authors (GLC and EB) conducted two independent literature reviews, both using the same strategy. All articles from 1978 to December 2021 were included if they reported findings relating to dysplasia or cancer of the pouch and/or the ATZ and/or the rectal cuff . Particular attention was paid to publications including endoscopic follow-up from which valuable conclusions could be drawn.Additional articles were identified by cross-referencing papers from the initial search. The search excluded articles that were not in English and non-human studies, as well as editorials. Studies on patients suffering from Crohn’s diseases or indeterminate colitis have not been included in this review, given the rarity of the situation and the specific issues .According to the largest prospective study published, the incidence of ATZ dysplasia was estimated at 4.5% 10 years after surgery . SeveralThe presence of dysplasia or cancer in the proctocolectomy specimen suggests that the patient is at risk of developing ATZ cancer ,34,55,56Ravitch gave the first description of adenocarcinoma of the pouch, per se, following RPC for UC in 1984 . Thirteep < 0.001) and dysplasia . A link with primary sclerosing cholangitis has been put forward as a risk factor for pouch dysplasia and cancer [The only risk factor identified for pouch cancer in this study was pre-operative colorectal cancer  . This atThis severe villous atrophy with chronic inflammation is assumed to highlight the risk of dysplasia and DNA aneuploidy ,139. PriMicrobiota are involved in the colonic metaplasia of the ileal reservoir ,141,142.Sulphate-reducing bacteria are associated with greater sulphomucin expression in pouches . SulphatDepleted levels of secondary bile acids (lithocholic acid and deoxycholic acid) have been found in the pouch of UC patients compared to FAP patients . Sinha eThe underlying pathology might also be involved in the risk of pouch inflammation, dysplasia and cancer. Indeed, compared to FAP patients, it has been proven that pro-inflammatory cytokines (such as TNFα) and pro-apoptotic proteins are up-regulated in endoscopically normal pouches of UC patients ,156. ModGenetic aberrations are assumed to occur during the metaplasia-dysplasia-cancer sequence of the pouch, similar to colorectal carcinogenesis. The only modification identified by Gullberg et al. was the loss of heterozygosity at chromosome 5q14-22 . ControvThe main references on all these underlying mechanisms could be as follows: ,143,146.Endoscopically, dysplasia and cancer of the pouch or ATZ can present as polypoid or non-polypoid lesions (including flat and ulcerated lesions) . Only loThe British Society of Gastroenterology (BSG) recommends annual pouchoscopy for high-risk asymptomatic patients, defined by the presence of at least one of the following criteria: type C mucosal changes, primary sclerosing cholangitis or RPC for dysplasia or cancer . The EurMore recently, consensus guidelines on the diagnosis and classifications of ileal pouch disorders have been published by the International Ileal Pouch Consortium . ExpertsThe therapeutic strategy is outlined in Moreover, Wu et al. suggested that a family history of colorectal cancer is associated with an increased risk of low-grade dysplasia progression . Hence, The use of chromoendoscopy with targeted biopsies has been assessed in only one study which failed to highlight any benefits with this technique . The useThe main references on endoscopic screening could be as follows: ,172,176.The cumulative risk of developing ATZ adenoma has been estimated by Van Duijvendijk et al. as 8 and 18% at 3.5 and 7 years post-surgery, respectively, . TsunodaNumerous cases of pouch adenomas following RPC for FAP have been reported ,205,206.p = 0.08) [High-grade dysplasia and adenocarcinomas of the pouch have been documented in case reports ,216,217. = 0.08) .The main references on epidemiology and risk factor could be as follows: ,196,207.The presence of residual rectal mucosa is one of the main reasons behind the onset of pouch adenomas in the case of stapled anastomosis . On the Despite removal of the entire rectal mucosa, colonic metaplasia of the ileal mucosa was still observed, as in UC ,225. An Friedrich et al. demonstrated that Glutathione S-transferase activity, which has a protective role in carcinogenesis, is lower in the pouch than in the proximal ileum . Paiva eA molecular study by Will et al. provides data on the APC mutation spectrum in pouch adenomas . In FAP,This high incidence of adenomas and reported cases of cancer of the pouch emphasize the need for endoscopic monitoring. The European Society of Gastrointestinal Endoscopy (ESGE) published guidelines in 2019 . It advoSome authors even advocate initiating thorough endoscopy monitoring 6 months and 1 year after surgery with 2 yearly follow-ups thereafter ,239. TheThe major limiting factor in endoscopic monitoring is poor patient compliance. Douma et al. estimated that 8% of pouch patients fail to comply with recommended monitoring procedures  mainly dAPC mutation), intestinal epithelial changes due to faecal stasis and the presence of residual rectal mucosa [We have collated available data on dysplasia and cancer of the ATZ and pouch in the case of UC and FAP. The overall incidence of pouch adenomas was assessed in up to 75% of patients 15 years post-surgery . The risl mucosa . Smith el mucosa . ParticuThe incidence rate of pouch adenocarcinoma has been estimated at 0.35% 20 years after surgery in UC patients . The undOur review has several limitations. First of all, many of the studies reported have retrospective, small sample size cohorts with heterogeneous follow-up. The heterogeneity of the surgical techniques used in the studies creates further bias ,181,191.Some studies assessing the risk of pouch adenomas in FAP patients do not specify the presence and extent of dysplasia within the adenomas ,194,195.Finally, some cohorts reported not one case of dysplasia or cancer of the ATZ (or cuff or pouch) despite long-term follow-up ,249,250.ATZ and ileal pouch cancers following RPC for FAP (or UC) are seldom detected in patients with IPAA. However, in view of the high mortality rate associated with this complication and given that pouchoscopy is a straightforward monitoring option, we recommend regular endoscopic monitoring for those patients. The development of endoscopic therapeutic options (less invasive than surgery) to remove dysplasia before cancer onset, further corroborates the need for a monitoring programme.Additional studies are required to improve our knowledge of the underlying mechanisms  that perpetuate the emergence of dysplasia and cancer. A greater understanding of the factors involved may lead to preventive treatments . This approach will help practitioners to identify those patients requiring follow-up and to initiate personalised endoscopic monitoring programmes.


One common way to aid coaching and seek to improve athletes’ performance is by recording training sessions for posterior analysis. In the case of sailing, coaches record videos from another boat, but usually rely on handheld devices, which may lead to issues with the footage and missing important moments. On the other hand, by autonomously recording the entire session with a fixed camera, the analysis becomes challenging owing to the length of the video and possible stabilization issues. In this work, we aim to facilitate the analysis of such full-session videos by automatically extracting maneuvers and providing a visualization framework to readily locate interesting moments. Moreover, we address issues related to image stability. Finally, an evaluation of the framework points to the benefits of video stabilization in this scenario and an appropriate accuracy of the maneuver detection method. To assess athletes’ performance during training sessions, in many sports, technology and data analysis are assuming an increasingly larger role. Nevertheless, for sailing, and more specifically, the Olympic dinghy class, such strategies are still not a common practice during training. This is mainly due to the lack of clear strategies for analyzing data obtained from sensors attached to the boats. Therefore, coaches rely mainly on videos to review athletes’ performance. Training sessions usually last 2–3 h, where the coach follows the training boat in a rigid inflatable boat (RIB).tacking and jibing, are the core of the sailors’ strategy to reach the finish line as quickly as possible. The maneuvers allow the boat to advance in a zig-zag manner because it cannot sail straight into the wind. Tacking occurs when a boat turns its bow (front part) against the wind and then keeps turning “through the wind” to catch the wind on the other side of the sail, whereas jibing occurs in the opposite direction. When performing such maneuvers, sailors usually move from one side of the boat to the other (they switch sides).Two maneuvers, known as When and how maneuvers are performed is critical in a race, as every second counts. Hence, they are an important skill to improve and master during training sessions. Coaches therefore record short video clips of the maneuvers, on the order of 1 min, to further discuss them during a debriefing session with the sailors.However, there is no structured or standard way to register these moments, and most coaches rely on handheld devices for recording, such as their personal smartphones. Because of this, many maneuvers that could be valuable for better analysis of the sailor’s performance are missed.To avoid the burden of manual capture, coaches have recently switched to cameras that are mounted on their boats and record an entire training session. Despite the clear advantages of relieving the coaches from the recording task and capturing important moments, the task of going through the entire video after a training session (or multiple training sessions) is too costly in terms of time. In addition, with handheld devices, the person registering the footage naturally applies manual stabilization by compensating for the boat’s movement while keeping the subject of interest in focus. On the other hand, this stabilizing effect is lost when the camera is mounted to the trailing boat.In this work, we address the above-mentioned issues associated with a mounted camera for recording sailing training sessions. Our main contribution is the provision of a pipeline that allows a less time-consuming visual analysis of recorded videos from entire training sessions. It includes stabilization based on the horizon line, extraction of maneuvers from recorded footage, and highlighting potentially interesting segments in time, which can in turn be explored and annotated using a visual interface developed in support of this study. This article is an invited extension of a formerly published conference paper  with speVideo visualization may assist users in their analysis by removing mechanical tasks, such as viewing the entire footage . Note thHiguchi et al.  proposedseeing is believing.” In the second case, the video is actively used and is considered as the main data input. For example, Legg et al. , a = 5, b = 0, using a step size of 0.005, as suggested by Haar Romeny [σ values in this range, the zero-crossing frames are stored as the ‘signatures,’ as depicted in Fig. In our adaptation, we first compute a Laplacian of Gaussian (LoG) filter with r Romeny . Using t.15 rad, we judge the location of the sailors to be stable. Likewise, when the slope of the line increases, we assume that the sailors are starting a maneuver. The slope of the line gradually decreases once they have crossed to the other side, marking the end of the maneuver. We consider the last stable frame before and the first stable frame after the crossing as the maneuver interval.Finally, we need to determine if the sailors remain long enough on the other side to consider it as an actual maneuver. For this purpose, we compute a regression line  on the lThe last stage of our pipeline is a visual analysis interface that enables exploration of a registered session containing detected maneuvers, as illustrated in Fig. We also provide a few tools that may aid a debriefing session. Users can include and remove intervals, mark intervals as important, and annotate selected intervals using the text-box on the left-hand side of the screen. While the timeline with contrasting colors gives a good overview of the potentially interesting events during the session, the thumbnails give an indication of what is occurring during a particular time interval. This facilitates the selection of interesting intervals and the removal of false positives generated by the automatic detection method.In this section, we explain the evaluation process and its outcomes. To evaluate the developed framework, a user study was conducted with seven Olympic-level sailing coaches. We divided the evaluation into several modules: video stabilization, maneuver detection, and general application.I is the maximum intensity that a pixel can have in image I. The mean-squared error (MSE) for consecutive frames with dimensions N × M is defined asTo evaluate stabilization, we used both qualitative and quantitative measures based on defined metrics. To objectively quantify the difference between the original video and the result of our stabilization method, we used the peak signal-to-noise ratio (PSNR). The assumption behind this metric is that if the transitions between consecutive frames are smooth, the similarity between consecutive frames is higher. This measurement is defined in decibels between consecutive frames asFigure The results from the quality measures suggest that the stabilized videos are slightly better, and we assume that these should be easier to analyze by a coach. To evaluate this assumption, seven coaches were shown three pairs of videos, each pair consisting of the original video and the stabilized version. Each example was recorded under different weather conditions: cloudy and medium waves, overcast conditions and large waves, and sunny weather under relatively calm seas. Later, for each pair of videos, we asked the following question, where video A was the original video and video B was the stabilized video:Which video (A or B) is easier to analyze?Strong preference for video A;Maybe video A;Both videos are equally easy/difficult;Maybe video B;Strong preference for video B“Each coach was then asked to vote on the three pairs of videos using a 5-point Likert scale. The results are shown in Fig. For the evaluation, we selected three videos where our assumptions were mostly satisfied (the sailing boat was followed from behind and was in full view of the camera). We removed situations in which these assumptions did not hold. Moreover, we selected videos in which sailing occurred under normal weather conditions. We manually tagged 27 maneuvers to assess our automatic method. The average sensitivity  was 72.72%, and three maneuvers were not detected.On the other hand, by not removing the moments when the assumptions did not hold, the number of false positives increased considerably (from 4 to 22). These false positives can be manually discarded via the visual interface.The adapted edge-focusing method predicted the exact crossing frame for 20 out of 27 maneuvers. The median offset was 26 frames, with an average of 45 frames. In practice, considering a 30 Hz video, the crossing moment would be off by 1 s, which is negligible in our application. Although more tests need to be conducted using larger amounts of data, this evaluation indicates the potential practical utility of our method.We conducted a user study involving seven coaches to evaluate the visual analysis framework developed for this study. The purpose of the study was to determine whether this tool is considered useful for coaching. The questionnaire consisted of the questions listed in Table for the relatively fast sailing boats, it is difficult to stay close during training.” Although these functionalities were outside the scope of this study, they can be easily added in the future.In response to Q1 in Table everything looks the same in the thumbnails and therefore it is not useful.” Another coach noted that “you need a way to label/name the thumbnails to be able to distinguish between them.”The responses to Q3 made us realize that the thumbnails did not give a clear indication of the content. As stated by one coach, “The answers from Q4 lead us to conclude that most coaches would likely use our framework in coaching, as shown in Fig. We presented a framework to detect maneuvers in a recorded sailing training session and an interface to aid in debriefing. Evaluation of the proposed stabilization method indicates that it increases the visual quality of the video. An immediate future step would be to remove distracting moving edges reported by the coaches participating in our survey.When our assumptions hold, most maneuvers are automatically detected with high precision of the crossing moment as sailors move from one side of the boat to the other. However, increasing the detection accuracy of the boat and the sailors is still desired. An option is to include sensor data that are sometimes used in training sessions.The visual interface developed to support debriefing allows coaches to locate interesting moments in the videos, thus avoiding having to search through the entire session manually. The evaluation indicates that our proposed framework provides a promising platform for coaches to analyze training sessions. In the future, we intend to perform further evaluations using more data in the form of training videos.


Video analysis is one of the most commonly applied methods for analysing football injuries.The objective of this study was to assess the accuracy of video analysis for recording head injuries in professional football from official matches in the four highest men’s professional football leagues in Germany.In this cohort study, head injuries detected by means of video analysis of all official matches over one season (2017–18) were compared to head injuries registered with the German statutory accident insurance.Our video analysis yielded 359 head injuries of 287 players. The comparison of head injuries found in our video analysis to those registered with the accident insurance only yielded a match in 23.1% (n = 83), which presents a rather low verification rate. The verification rates varied between the leagues (7.0–30.8%). All injuries documented in the accident insurance registry were found in the video analysis (100%). The types of head injury most often verified by the accident insurance registry (n = 83) were contusion (43.4%), bone fractures (19.3%) and skin lacerations (18.1%). Only 66 of the 359 head injuries (18.4%) resulted in absence from at least one training session and involved a mean time loss of 18.5 days (1–87 days).The mismatch between the number of head injuries found in the video analysis and head injuries registered with the accident insurance is an important methodological issue in scientific research. The low verification rate seems to be due to the unclear correlation between injury severity and clinical consequences of head injuries detected by means of video analysis and the failure of football clubs to register minor head injuries with the accident insurance. Football represents one of the most popular sports worldwide and has a considerable sports-specific injury risk , 2. EpidIn several previous studies, the registration of head injuries based on video analysis was an appropriate tool for characterising the consequences of head injuries and the need of medical treatment of football players , 15, 16.st and 2nd Bundesliga, 3rd and 4th league). The first part of this study consisted of a standardised video analysis using publicly available video material over one season (2017–18). For the 1st and 2nd Bundesliga, we used video material of the national pay television channel ‘Sky’ and for the 3rd and 4th league an online portal account ‘die-ligen.de’, both provided by the national football association. Over one season, we documented each head injury event in every official match for which video material was available in full length. For head injuries, we used the model of critical incidents (CI) according to the criteria first published by Anderson et al (2004) and further developed by Bjoernboe et al (2014) . The frequency of head injuries was calculated with the number of Critical Incidents on the head and is shown as incidence for 1000 h match exposure. Descriptive data such as injury characteristics are presented as absolute numbers, percentages in parentheses and mean where appropriate. Data of the verification process are presented as percentages and absolute numbers. All analyses were done with Microsoft Excel®.st and 2nd Bundesliga and the 3rd and 4th league were documented by means of video analysis. 28 players (9.8%) sustained 2 head injuries and 13 players more than 2 head injuries (4.5%). The number of head injuries was higher in the 1st and 2nd Bundesliga than in the 3rd and 4th league. Defenders followed by midfielders sustained the most head injuries  followed by the 2nd Bundesliga (25.2%)  . The seaThe 83 diagnosed head injuries verified by the insurance company showed contusion (43.4%), bone fractures (19.3%) and skin lacerations (18.1%) as the most common types of head injuries in professional football. The rate of concussion was 8.4% .66 head injuries (18.4%) diagnosed by means of video analysis resulted in absence from sports of at least one training session . Of thesst Bundesliga with 148 injuries. The body site most affected by recurrent injury after a head injury was the thigh muscles (21.6%) followed by the ankle joints (16.6%). 7.2% of the players had sustained recurrent injury to the head; players of the 4th league had the highest rate of recurrent injury to the head with 10.0% compared to the rate of other leagues of 5.2–9.5%  had sustained recurrent injuries (n = 374) to different body sites in the further course of the season. The rate of recurrent injury was highest for players in the 15.2–9.5% .All head injuries verified by means of accident insurance registry were detected in the video analysis, which shows the effectiveness of video analysis in detecting head injuries. Almost 80% of head impacts detected by video analysis had not been documented in the insurance registry, which represents a large proportion of head injuries with unclear clinical impact or consequences. Potential sub-concussive head impacts may remain undetected by physicians and hence not be registered with the accident insurance company . The resVideo analysis represents a further type of injury assessment in addition to the injury registry of the accident insurance, which is also well described in the literature. Previous scientific publications used accident insurance data to provide detailed knowledge about injuries in amateur and professional sports , 25. TheIn this study, 83 verified head injuries were severe injuries such as fractures or concussion, which represents a high percentage of severe injury types in this sample. It is a well-known fact that over 50% of head injuries in sports populations are overlooked and often result in neurological symptoms, and this percentage gives an impression of the real frequency of severe head injuries in daily sports . The sevThis study is the first assessment of head injuries in video analysis that is verified by accident insurance data, but the study is not without limitations. First, head injuries were only analysed over one season. The second limitation is the ethical guideline of this study and the accident insurance guidelines, which only allowed the inclusion of anonymous data. Therefore, it was not possible to carry out further sub-investigations after the blinded verification of the video analysis data by means of the accident insurance data. A further weakness of injury registration with the accident insurance already reported by Klein et al in 2019 is the lack of information on overuse and non-traumatic injuries . ScientiThe mismatch in the frequency of head injuries between video analysis and insurance registry shows the weakness of current head injury registration and the possible underreporting by medical staff. The inability of video analysis to indicate the severity and clinical consequences of a head injury and the failure of clubs to register minor head injuries with the accident insurance seem to be probable factors for the discrepancy between the two assessment methods. Especially the rate of head injuries underreported to the accident insurance registry is remarkable. Further scientific investigations should focus on this topic to strengthen awareness when evaluating head injuries. Because head injuries are caused by typical contact mechanisms, the accident insurance registry seems to be an appropriate tool for addressing the accurate number of head injuries. Further research is necessary to investigate valid injury analysis for head injuries, especially in the case of sub-concussive impacts.


Nutritional status in oncological patients may differ according to several modifiable and non-modifiable factors. Knowledge of the epidemiology of malnutrition/cachexia/sarcopenia may help to manage these complications early in the course of treatment, potentially impacting patient quality of life, treatment intensity, and disease outcome. Therefore, this narrative review aimed to critically evaluate the current evidence on the combined impact of tumor- and treatment-related factors on nutritional status and to draw some practical conclusions to support the multidisciplinary management of malnutrition in cancer patients. A comprehensive literature search was performed from January 2010 to December 2020 using different combinations of pertinent keywords and a critical evaluation of retrieved literature papers was conducted. The results show that the prevalence of weight loss and associated symptoms is quite heterogeneous and needs to be assessed with recognized criteria, thus allowing a clear classification and standardization of therapeutic interventions. There is a large range of variability influenced by age and social factors, comorbidities, and setting of cures . Tumor subsite is one of the major determinants of malnutrition, with pancreatic, esophageal, and other gastroenteric cancers, head and neck, and lung cancers having the highest prevalence. The advanced stage is also linked to a higher risk of developing malnutrition, as an expression of the relationship between tumor burden, inflammatory status, reduced caloric intake, and malabsorption. Finally, treatment type influences the risk of nutritional issues, both for locoregional approaches (surgery and radiotherapy) and for systemic treatment. Interestingly, personalized approaches based on the selection of the most predictive malnutrition definitions for postoperative complications according to cancer type and knowledge of specific nutritional problems associated with some new agents may positively impact disease course. Sharing common knowledge between oncologists and nutritionists may help to better address and treat malnutrition in this population. Malnutrition is a frequent hallmark of cancer patients, resulting in unintentional weight loss due to a lack of intake or uptake of nutrients . This coPatients’ nutritional issues should be considered as a continuum, in an ideal line from the first signs and symptoms of anorexia to precachexia, cachexia, and refractory cachexia. As in a pyramid, refractory cachexia represents the highest part, while the vast basis is made up of initial nutritional impairment . HoweverTherefore, it is essential to periodically assess cancer patients during the different phases of the treatment journey. As a matter of fact, nutritional status is not a fixed condition, but a changeable status. Tumor stage, treatment type and setting, and comorbidities influence the nutritional needs of the patient, requiring a continuous evaluation of the nutritional, inflammatory and metabolic pathways. In addition, there are huge differences among tumor types and treatment settings, so that one can tailor the nutritional interventions according to the existing risk.Moreover, the definitions of malnutrition, cachexia and sarcopenia have not been uniformly employed within clinical reports, therefore often complicating the identification of their prevalence among cancer patients. Malnutrition is present with the diagnosis of cancer in about 15–40% of cases and this incidence increases during treatment, characterizing 40–80% of the patients in this phase [In this complex scenario, this narrative review aimed to evaluate the current evidence on the combined impact of tumor- and treatment-related factors on nutritional status with a particular emphasis related to the subsite of disease and phase of treatment, in order to help depict the heterogeneous pattern of malnutrition and to provide some practical conclusions to support the multidisciplinary management of this condition. We performed a critical evaluation of the literature papers from January 2010 to December 2020, giving an overview of the complex pattern and relationships existing between malnutrition, sarcopenia and cachexia in cancer patients. A comprehensive literature search was conducted using MEDLINE, with different combinations of pertinent keywords. The following terms were considered: “malnutrition”, “sarcopenia”, “cachexia”, “cancer”, “surgery”, “radiation therapy”, “chemotherapy”, “targeted agents”, “immunotherapy”, and “palliative care”. Authors were asked to identify further references from their personal collection of literature or other sources and they chose the most relevant manuscripts to be included in the present review. Each author then drafted a section of the review, comprising the evidence from literature and a critical evaluation according to their personal clinical experience on the topic. Each contribution was then reviewed and harmonized with the others by all the authors and a final version of the paper was circulated and approved.Early recognition of malnutrition is essential for the correct management of the cancer patient. To identify and treat patients with malnutrition or those at high nutritional risk, a nutritional screening and a full nutritional assessment should be performed .Nutritional screening should be performed at the time of the diagnosis, preferably before starting anticancer treatments. Several validated screenings tools are available for identifying a malnutrition status or a risk of developing malnutrition, for instance (a) the Nutritional Risk Screening 2002 (NRS 2002), (b) the Malnutrition Universal Screening Tool (MUST), and (c) the Mini Nutritional Assessment (MNA). Nutritional screenings should be repeated regularly throughout the therapeutic process, especially in cancer types with a high impact on nutritional status .Patients at risk of malnutrition, according to the results of nutritional screening, should be referred to a clinical nutrition service for nutritional assessment and treatment.Anthropometric measurements: Actual body weight, height, body mass index (BMI).Weight loss evaluation: An unintentional weight loss of >5% in the last six months is considered clinically relevant .Assessment of body composition through bioelectrical impedance vector analysis (BIVA): As a matter of fact, it allows a more detailed understanding of hydration status and cell mass that may be modified by pathological conditions. Moreover, the determination of phase angle seems to be a predictive outcome parameter in cancer patients . Lean maNutritional assessment for malnutrition and sarcopenia should include:Biochemical data related to inflammatory and metabolic status: serum albumin, prealbumin, total lymphocyte count cholesterol, C reactive protein (CRP), transferrin, interleukin-6 (IL-6), and fibrinogen.Evaluation of nutritional intake, appetite, resting energy expenditure (REE) using indirect calorimetry, physical activity levels using metabolic holters .Evaluation of sarcopenia parameters : muscle Quality of Life and functional skills through specific questionnaires.Computed tomography (CT) and magnetic resonance imaging (MRI) constitute the gold standard techniques to assess body composition ,11. The The accuracy of nutritional status determination is achievable with the combination of the described parameters. In this regard, the use of simple anthropometric measures may not provide information on body composition alterations, especially on the reduction of muscle mass, which may occur regardless of weight loss or BMI in cancer patients ,24. Low In 2016, the GLIM criteria for malnutrition diagnosis were identified . FirstlyThe diagnosis of malnutrition requires at least one phenotypic criterion and one etiologic criterion. Phenotypic criteria are also used to divide the severity of malnutrition into Stage 1 (moderate) or Stage 2 (severe), as shown in Novel approaches to the diagnosis of sarcopenia have been evaluated to determine muscle mass, muscle function, skeletal muscle index (SMI) and impact on Qol ,27,28 ThThese tools need to be validated, reliable, and accurate for future use in clinical practice ,40. GlobMalnutrition may affect as many as 75% of cancer patients ,42 with However, despite this mixture of factors influencing the nutritional status and the diagnosis of malnutrition, specific cancer types have been consistently associated with a higher risk of malnutrition and of developing cachexia. This condition is the result of tumor-induced activation of inflammatory pathways , which tMalnutrition is also very common in cancers that affect gastrointestinal function , such as esophagus and stomach neoplasms. In this group of tumors, however, the concomitant involvement of systemic inflammation in malnutrition and cachexia has been demonstrated .Many studies addressing the overall prevalence of malnutrition according to cancer type in different countries and settings have been published over the years and are reported in It should be mentioned that these tumor types are associated with protein-energy malnutrition and cachexia. Malnutrition in the context of obesity is notably a risk factor for the development and recurrence of other types of cancers (such as gynecologic and colon tumors)  althoughBy using the Nutritional Risk Screening NRS 2002), Bozzetti et al.  and Plan002, BozzHigh prevalence of increased nutritional risk or overt malnutrition apply also to head and neck cancers. In this group, rates of increased nutritional risk ranging from 28.6%  to 67%  and of oWhen addressing lung tumors, increased nutritional risk has been reported in 26.6–42.9% of patients ,59,62. TMalnutrition is also frequently associated with hematologic malignancies with rates of 34–36.8% ,60,63. T2 associated with progressive weight loss (>2% in six months), or (c) a weight loss >2% in 6 months combined with low muscle mass [The prevalence of severe malnutrition, i.e., cachexia in cancer patients, has been reported by numerous studies ,67,68. DBesides isolated unintentional weight loss or associated with loss of body fat, the spectrum of nutritional abnormalities in cancer patients also includes sarcopenia, defined by a reduction of muscle mass and function typical of the aging process . SarcopeOverall, these data confirm the high risk and prevalence of malnutrition and cachexia in some cancer types, for which therefore special attention should be paid in the early disease stage. Due to the prognostic implications of malnutrition and low muscle mass on treatment tolerance, quality of life, and survival, routine screening and assessment of malnutrition should be warranted in all cancer patients, but especially in those affected by tumors localized in gastrointestinal pancreatic, head and neck, and lung districts.Surgery is the mainstay of treatment in many solid tumors with more than 80% of patients requiring an operation in the treatment pathway . In the Malnutrition is indeed a modifiable risk factor for surgery. Perioperative nutritional support is very effective in decreasing non-infectious and infectious complications and also the length of hospital stay . As alreDifferent cancer types are related to variable malnutrition status and also the definition of malnutrition can differ in the different surgical settings ,81. TailOne upcoming issue is the variability amongst different cancer types regarding the most common specific definition of malnutrition. With all the limitations of a single study, they support the idea that, according to the cancer type, the malnutrition definition that best predicted postoperative risk differed for six cancer types and is: severe malnutrition for colorectal cancer, ESPEN 2 for esophageal cancer, ESPEN 1 for gastric, lung, and pancreatic tumors, and NSQIP for liver cancer. Accurate risk stratification for the type of cancer and type of surgery would therefore allow for rehabilitation in high-risk patients and perhaps improve outcomes. This introduces the concept of personalization, not only of treatment but also of evaluation according to cancer type. Unfortunately, the actual attention paid to nutritional status is far from the standard required in oncology treatment .Radiation treatment is employed as a curative treatment both in the postoperative setting and as an exclusive approach in many cancers. In recent years, the refinement of treatment schedules, technical improvements, and better association with systemic drugs have increased the potential of this therapeutic approach.The balance between efficacy and toxicity has been one of the most discussed issues. Sometimes, the boundary between them is not so clearly defined and the therapeutic window may be narrow. In this regard, treatment of head and neck cancer patients represents one of the most challenging ones, as radiation therapy increases locoregional control and improves outcome, is also employed as an organ-preservation strategy, but it is burdened by many toxicities, mainly on the mucosal tract. This implies that weight loss is often a treatment-limiting toxicity if accurate nutritional programs are not fully implemented. Dysphagia, dysgeusia, pain swallowing, and mucositis represent the most frequent adverse events by radiation, amplified by concurrent systemic treatments. In a recent study, at population-based data, and considering the ESPEN-recommended weight loss grade, at the time of diagnosis grade 1–2 malnutrition was present in 33% of the patients, whilst grade 3–4 malnutrition was found in 24% of the patients ,85. MoreIt should be underlined that similar consequences of malnutrition have been reported also in other cancer subsites, where weight loss at baseline and during radiation are common treatment-induced toxicities. In esophageal cancer, malnutrition is a frequent hallmark of patients at diagnosis, and nutritional support has been extensively suggested, particularly for patients undergoing radiation therapy ,59. MoreMalnutrition during oncological systemic treatments may expose patients to a dangerous, vicious circle. In fact, from one side, malnutrition is a consequence of the treatments themselves, as one of the possible side effects. Dysgeusia, nausea, vomiting, anorexia, mucositis, and dysphagia induced by chemotherapy are just some toxicities that may result in malnutrition. On the other side, the lack of an adequate nutritional status puts the patients at higher risk of developing toxicities, and it is one of the major causes of poor tolerance to the therapies . MoreoveIn patients undergoing chemotherapy, the presence of gastroenteric symptoms is closely linked to unintentional weight loss . Among dThe exact prevalence of nutritional issues induced by immunotherapy has not been comprehensively studied. Some adverse effects caused by immune checkpoint inhibitors could justify a causal role of this treatment in reducing intake and absorption of nutrients: diarrhea, pancreatic insufficiency, nausea and fatigue might reduce the caloric intake and produce weight loss. On the other side, there remains evidence showing that cancer-induced chronic inflammation and impairment of nutritional intake impair the quality of immune response, both innate and adaptative . It is tThere is no consensus on the definition of end-of-life. Indeed, the term may refer to “people at risk of dying within the next 12 months” according to the guidance of the General Medical Council of 2010 (4) or to “the final weeks, days, hours of a patient’s life” according to the NHS document on end-of-life care strategy .It is therefore clear that life expectancy is a very important parameter, but it is often very difficult to establish it.Cancer patients at the end of life are often characterized by a worsening of nutritional status determined by a gradual reduction in food intake and progressive weight loss. The causes may be multifactorial, directly linked to the neoplastic disease or its treatment, such as anorexia, nausea, vomiting, dysgeusia, dysphagia, diarrhea, or linked to obstruction of the gastroenteric tract. Many patients develop severe malnutrition and dehydration ,99.Regarding end-of-life as a life expectancy of a few weeks, every intervention should be considered together with ethical aspects. Such intervention should be non-invasive and limited to symptom management considering personal and family expectations and the benefits of quality of life .The spectrum and magnitude of nutritional disorders in oncological patients vary according to cancer type, disease setting, comorbidities, and type of treatment performed. The prevalence of weight loss and associated symptoms is quite heterogeneous and needs to be assessed with recognized criteria, thus allowing a clear classification and standardization of therapeutic interventions. The analysis of the literature has not been conducted with the criteria of a systematic review, as the purpose of this paper is to shed light on a complex issue with the eyes of different expertise.−Malnutrition is highly prevalent in certain cancer types and at advanced stages. Early screening and periodical reassessment are mandatory.−Personalized choice of best malnutrition definition according to cancer site allows an accurate risk stratification for postoperative complications and targeted preoperative interventions.−In radiotherapy, the boundary between efficacy and toxicity is not so clearly defined. Therefore, careful monitoring and implementation of nutritional support prevent weight loss-associated adverse complications.−Nutrition-related problems are common during chemotherapy, but their exact prevalence during targeted treatments is generally unknown. This does not hold true for selected agents, such as hedgehog inhibitors, which extensively affect nutritional intake and status by specific mechanisms. Appropriate interventions should be provided in a timely and appropriate manner.−End-of-life period interventions should be targeted at patient comfort and quality of life. Therefore, we state that since nutritional issues have a relevant impact on patient quality of life, treatment intensity, and disease outcome, it is important that both oncologists and nutritionists share and address the following key points:


Diamine-appended variants of the metal–organic framework Mg2(dobpdc)  are promising materials for CO2 capture because of their cooperative chemisorption mechanism and associated step-shaped equilibrium isotherms, which enable large working capacities to be accessed with small temperature swings. However, the adsorption/desorption kinetics of these unique materials remain understudied. More generally, despite the necessity of kinetics characterization to advance adsorbents toward commercial separations, detailed kinetic studies of metal–organic framework-based gas separations remain rare. Here, we systematically investigate the CO2 adsorption kinetics of diamine-appended Mg2(dobpdc) variants using a thermogravimetric analysis (TGA) assay. In particular, we examine the effects of diamine structure, temperature, and partial pressure on CO2 adsorption and desorption kinetics. Importantly, most diamine-appended Mg2(dobpdc) variants exhibit an induction period prior to reaching the maximum rate of CO2 adsorption, which we attribute to their unique cooperative chemisorption mechanism. In addition, these materials exhibit inverse Arrhenius behavior, displaying faster adsorption kinetics and shorter induction periods at lower temperatures. Using the Avrami model for nucleation and growth kinetics, we determine rate constants for CO2 adsorption and quantitatively compare rate constants among different diamine-appended variants. Overall, these results provide guidelines for optimizing adsorbent design to facilitate CO2 capture from diverse target streams and highlight kinetic phenomena relevant for other materials in which cooperative chemisorption mechanisms are operative.Carbon capture and sequestration is a key element of global initiatives to minimize anthropogenic greenhouse gas emissions. Although many investigations of new candidate CO 2 adsorption kinetics of a promising class of cooperative carbon capture materials offers new insight into their structure-performance properties.An in-depth investigation of the CO Rapid kinetics to bind and release CO2 are also critical, because they can dictate bed utilization and thus impact the cost and efficiency of a carbon capture process.4Steadily rising atmospheric CO2 capture technology, but they suffer from numerous drawbacks. For example, solutions with relatively low amine concentrations are necessary to minimize corrosive effects, thereby decreasing the solution CO2 absorption capacities and increasing the energy required to heat the absorbent during temperature-swing cycling.5 As a result, the implementation of aqueous amine scrubbers in a power plant places a parasitic load of 25–30% on the net power output.6 Furthermore, aqueous amine solutions are prone to thermal and oxidative degradation.3 As an alternative, porous solid adsorbents have been proposed as capture materials, owing to their lower heat capacities and high surface areas, which create the potential for high adsorption capacities and more efficient adsorption–desorption cycling. Nevertheless, many of these solid adsorbents fail to capture CO2 selectively from humid gas streams.7Aqueous solutions of organic amines are a mature CO8–11 porous polymers,12,13 zeolites,14,15 and metal–organic frameworks.16–20 Owing to their high crystallinity and chemical adjustability, metal–organic frameworks possess ordered structures that can be tailored with respect to pore size, shape, and chemical environment. In particular, amine functionalities can be incorporated within the organic linkers of these materials, both during framework synthesis21 or through post-synthetic modification.16–20,22 Additionally, the high internal surface areas accessible with metal–organic frameworks can allow for rapid diffusion of CO2 through the pores.23 Diamine-appended variants of the metal–organic framework Mg2(dobpdc)24–31  represent a particularly promising class of amine-functionalized frameworks, as they readily adsorb CO2 through a chemically-specific, cooperative mechanism  exhibit step-shaped CO2 adsorption profiles, which give rise to large CO2 cycling capacities that are accessible with relatively small temperature swings.25 Importantly, by varying the metal cation,25 diamine,26–28 or organic linker,28 the adsorption step position can be tuned in pressure by over five orders of magnitude (from ∼10−5 to ∼1 bar at 40 °C) to enable the precise targeting of specific CO2 separation conditions. Moreover, these materials have also been shown to maintain high CO2 working capacities after 1000 adsorption/desorption cycles under humid gas streams.27Amine-functionalized solid adsorbents combine the advantages of aqueous amine solutions and porous solid adsorbents. Examples of these materials include amine-functionalized silicas,echanism .25 Here,2 capture in diamine-appended variants of Mg2(dobpdc) are promising for numerous carbon capture applications, the kinetics also play a crucial role in the practical application of these materials. For porous solid adsorbents, small-scale breakthrough experiments are often used to simulate a fixed-bed adsorption process. In these experiments, shaped particles of the adsorbent are packed into a column, a CO2-containing gas stream is fed through the inlet, and the outlet composition and flow rate are measured as a function of time until CO2 “breaks through.” Multiple kinetic parameters can influence the performance of an adsorbent in a fixed bed, including interparticle, intraparticle, and micropore diffusional resistances, as well as potential reaction limitations for amine-based chemisorption of CO2. Critically, the overall CO2 adsorption kinetics must be sufficiently fast to maximize bed utilization in the process. Promising initial results have been obtained for diamine-appended Mg2(dobpdc) variants in gram-scale breakthrough experiments for CO2 capture from simulated coal flue gas (15% CO2 in N2) under both dry and humid conditions.27 In addition, rapid cycle times have been employed for diamine-appended Mg2(dobpdc) variants in simulated temperature-swing experiments under 15% CO2 with a pure CO2 purge, and here cycle times were limited only by the temperature ramp rate of the thermogravimetric analyzer.27,28While the thermodynamics of CO2(dobpdc) for CO2 capture applications, a detailed analysis of the kinetics of CO2 adsorption in these materials is necessary for optimal process implementation. Toward this end, we herein utilize thermogravimetric analysis (TGA) to systematically investigate the dry CO2 adsorption kinetics in diamine-appended variants of Mg2(dobpdc) under a range of adsorption conditions. Our results demonstrate the influence of adsorption temperature, CO2 concentration, and diamine structure on the rate of adsorption. On the basis of these correlations, we conclude with guidelines for the optimization of adsorbent structure and process parameters in CO2 capture applications.Given the promise of diamine-appended Mg2(dobpdc) were synthesized using our previously reported procedure.26 Specifically, methanol-solvated Mg2(dobpdc) was soaked in a 20% (v/v) toluene solution of the diamine of interest, and subsequent filtration, washing with toluene, and activation yielded adsorbents with one diamine per metal site. To ensure internal consistency for this study, all experiments were performed with the same batch of Mg2(dobpdc). The rod-shaped crystallites in this batch exhibited an aspect ratio of ∼10 and were heterogeneous in size, with widths ranging from ∼60 nm to >1 μm  samples in powder form; future studies will explore adsorption/desorption kinetics in structured forms of these materials.Diamine-appended variants of Mgm Fig. S1. Measure2 adsorption kinetics of diamine-appended Mg2(dobpdc). In this assay, samples were first activated in the TGA furnace under flowing N2 to remove any captured CO2, solvent, or excess diamine present in the pores. Next, samples were cooled to a temperature of interest, the gas flow was switched to a CO2-containing stream, and the change in mass was monitored as a function of time  used in this work  variants under the conditions relevant for CO2 chemisorption). As a result, determining CO2 adsorption kinetics under humid conditions remains challenging, and here we discuss only dry adsorption/desorption kinetics profiles. In addition, the first few points of kinetics data from a TGA experiment are obscured by exchange of the initial gas in the furnace with the CO2-containing stream in adsorption experiments or the N2 purge stream in desorption experiments.This TGA-based assay, which has been reported for fundamental kinetics characterization of other solid CO11 differences in flow rate and sample mass can also greatly affect TGA adsorption kinetics profiles. For example, in the case of m-2-m–Mg2(dobpdc) , we found that the sample mass has a substantial impact on adsorption kinetics from a simulated coal flue gas stream of 15% CO2 in N2,36 with larger samples displaying slower overall adsorption kinetics , adsorption was essentially complete within the first few data points collected on the TGA, making it difficult to quantitatively compare the kinetics among different adsorbents under these conditions. We therefore used a consistent flow rate of 25 mL min−1 for all experiments to facilitate quantitative comparisons among the diamine-appended variants. Under these conditions, a consistent delay of 19 s was observed before the sample mass increased, after switching the TGA valving to the analysis gas. This delay time corresponds to the time required for CO2 to reach the sample in the TGA furnace. Additionally, given a flow rate of 25 mL min−1, we approximate that at least 14–23 s are required at temperatures ranging from 120 to 30 °C for complete exchange of gases in the TGA furnace, beyond the initial 19 s delay , the first reported diamine-appended variant of Mg2(dobpdc),24 at selected temperatures. Extensive gas adsorption, structural, and spectroscopic data have been previously reported for this material,24–26 and an overview of the adsorption mechanism is shown in 2 adsorption kinetics of m-2-m–Mg2(dobpdc) from a pure CO2 stream at atmospheric pressure over a range of temperatures below the adsorption step temperature (Tstep) of 127 °C,26 defined here as the onset of the step-shaped adsorption isobar  vs. time  is relatively insensitive to temperature below Tstep,26 lower adsorption temperatures promote more rapid saturation with CO2. A more in-depth discussion of this phenomenon is provided below (see “Inverse Arrhenius behavior”).We utilized our optimized TGA assay to characterize the COn isobar . Rapid uvs. time . Interesbehavior . Such in2 first entering the furnace, and the time associated with the fastest rate of CO2 uptake (Tstep. To elucidate whether the observed induction period is intrinsic to the CO2 adsorption kinetics of m-2-m–Mg2(dobpdc) or is an artifact of the experimental setup, we investigated CO2 adsorption in the bare framework material with no appended diamines, Mg2(dobpdc) (2(dobpdc), CO2 binds to open metal coordination sites exposed upon solvent removal from the framework, leading to a typical Langmuir adsorption profile  does not involve a chemical reaction, the adsorption kinetics are likely diffusion-limited. Consistently, Mg2(dobpdc) reaches its equilibrium CO2 adsorption capacity within a similarly short time for all temperatures examined (2(dobpdc). For example, at 120 °C, approximately 51 s elapses before the maximum rate of adsorption is achieved in m-2-m–Mg2(dobpdc), whereas the maximum rate is reached in only 14 s for bare Mg2(dobpdc) under the same conditions (see asterisks in 2(dobpdc) at the low partial pressures present in the TGA furnace during the initial mixing period  include competition of N2 and CO2 for the same binding sites, and thus CO2 adsorption requires displacement of any adsorbed N2 molecules. Nevertheless, only a small fraction of metal sites (∼2–10%) is expected to be occupied by N2 under the conditions examined here, based on previously reported N2 adsorption isotherms for the isoreticular smaller-pore framework material Mg2(dobdc).39In addition to this inverse Arrhenius behavior, we also observed an induction period between the time at which the mass begins to increase, which corresponds to CO2 uptake . This ef(dobpdc) . In Mg2 and amine-appended m-2-m–Mg2(dobpdc) also exhibit distinct trends in their variable–temperature equilibrium CO2 adsorption capacities (Qe). Whereas the CO2 saturation capacity of m-2-m–Mg2(dobpdc) is similar across nearly all temperatures investigated, decreasing only near Tstep (2(dobpdc) varies substantially with temperature (Qt/Qe) vs. time (2(dobpdc), with induction periods observed at temperatures close to Tstep. In contrast, the adsorption profiles are similar at all temperatures for Mg2(dobpdc), with the highest temperatures exhibiting the fastest initial progress toward equilibrium. Overall, these findings corroborate that the chemisorptive mechanism operational in m-2-m–Mg2(dobpdc) leads to an unusual induction period that is not observed in the physisorptive mechanism in Mg2(dobpdc).In addition to the marked differences in the kinetics of COar Tstep , the capperature . This diperature . To quanvs. time . This an2(dobpdc), we characterized the adsorption kinetics from a 15% CO2 stream  is lower than that used in the experiments with 100% CO2 (75–120 °C), reflecting the lower adsorption step temperature under 15% CO2 (102 °C) compared to 100% CO2 (127 °C) , followed by a period of 4 min during which almost no additional adsorption occurred. After 5 min, the rate of CO2 adsorption accelerated, and a substantial CO2 occupancy was ultimately reached, corresponding to occupation of approximately half of the diamine sites. The fast capture of CO2 at ∼6% of the m-2-m sites, as shown in 2(dobpdc) adsorbs a small amount of CO2 even at pressures below the step.24,25 Spectroscopic studies indicate that this pre-step chemisorption arises due to ammonium carbamate species that form without metal–amine insertion.7 We hypothesize that the pre-step ammonium carbamate species forms rapidly, followed by slower cooperative adsorption of additional CO2via the formation of metal-bound ammonium carbamate chains. Qualitatively similar results were obtained using a 5% CO2 stream, for which the induction period is even more pronounced  Fig. S8. At tempd Fig. S6.2(dobpdc) is directly related to its cooperative CO2 adsorption mechanism. This material exhibits a high degree of cooperativity in equilibrium gas adsorption isotherms, with its Hill coefficient of ∼11 indicating that, from a thermodynamic standpoint, capturing one CO2 molecule facilitates the adsorption of subsequent CO2 molecules.25 The pronounced sigmoidal kinetics profile exhibited by m-2-m–Mg2(dobpdc) likewise suggests that initial capture of a CO2 molecule also enhances the adsorption kinetics of subsequent CO2 molecules. Similar sigmoidal kinetic profiles have been reported previously for autocatalytic40 and autoinductive41 chemical reactions. While a recent TGA-based assay previously revealed that a polyethylenimine-appended mesoporous silica also exhibited sigmoidal CO2 adsorption kinetics,11 amine-impregnated clays did not exhibit sigmoidal uptake kinetics when evaluated using comparable TGA equipment and procedures.34 These precedents establish that not all amine-based CO2 adsorbents exhibit sigmoidal kinetics. As noted in a recent study,42 a long induction period is undesirable for implementation in a practical process because it can lead to lower bed utilization. Specifically, in breakthrough experiments simulating direct air capture with m-2-m–Mg2(dobpdc), it was found that after rapid partial breakthrough of CO2, the CO2 concentration at the outlet decreased before full breakthrough eventually occurred, consistent with a delayed onset of adsorption.42 Hence, it is critical to identify appropriate diamine variants and/or CO2 adsorption conditions that minimize this induction period (see below).Taken together, these results suggest that the sigmoidal kinetics profile of m-2-m–Mg2 adsorption kinetics of m-2-m–Mg2(dobpdc) from a gas stream of 15% CO2 in N2. The fraction of sites occupied at time t (Qt) was fit at each temperature using either a pseudo-first order model  is embedded in the rate constant k1 or kA, respectively, and that nA in the Avrami model is also likely a function of P/P0. As expected, a pseudo-first order model using rate constant k1  . Notably, the x-intercept of this plot (kA = 0) should correspond to Tstep; indeed, the x-intercept of a linear fit to the high-temperature data (70–95 °C) of 100 °C is close to the step temperature determined by cooling a sample of m-2-m–Mg2(dobpdc) under 15% CO2  and longer induction periods (larger nA) at high temperatures close to the step temperature in m-2-m–Mg2(dobpdc). The smaller values of nA at lower temperatures reflect shorter induction periods and demonstrate an advantage of maintaining a buffer between the adsorption temperature and the step temperature.A plot of the Avrami rate constant (dobpdc) . At temp40,46–49 In general, inverse Arrhenius behavior requires the reversible formation of an intermediate species with equilibrium constant Keq that (i) is lower in energy than the reactant(s), with energy difference Δgint; and (ii) proceeds to product formation through a transition state, with kinetic barrier Δg‡rxn, that is also lower in free energy than the reactant(s), such that |Δg‡rxn| < |Δgint|  more than it promotes overcoming the barrier to form the product. In m-2-m–Mg2(dobpdc), reversible adsorption of CO2 to form a labile intermediate, such as a physisorbed or weakly chemisorbed species, likely precedes an exothermic rate-determining chemisorption step. The final product of chemisorption is an ammonium carbamate chain,26 which forms with a thermodynamic free energy change of Δgads. However, C–N bond formation, proton transfer, and metal–oxygen bond formation must all occur between the starting material and the final ammonium carbamate chains; the number of steps in this reaction pathway and the rate-determining step remain points of ongoing investigation. Nevertheless, the temperature dependence of the kinetics of CO2 adsorption in m-2-m–Mg2(dobpdc) is consistent with an overall mechanistic model involving the reversible formation of an entropically disfavored, CO2-bound intermediate followed by a rate-determining chemisorption step. A similar model can be invoked to explain the observed inverse Arrhenius behavior of CO2 adsorption in other amine-functionalized adsorbents.11,37The inverse Arrhenius behavior observed here can be rationalized using a reaction coordinate diagram derived from several previous investigations of reactions with apparent negative activation energies .40,46–49int| see . In addi2(dobpdc), we constructed an Arrhenius plot using the Avrami rate constants given in kA) increases with 1/T  is greatest close to Tstep.To further understand the behavior of m-2-m–Mgwith 1/T , and thear Tstep . The dat2 adsorption in m-2-m–Mg2(dobpdc), it does not necessarily predict the extreme curvature of the Arrhenius plot near 1/Tstep. Because cooperative CO2 adsorption does not occur above Tstep, the Arrhenius plot for the cooperative adsorption process should deviate to −∞ upon approaching Tstep from low to high temperature. Discontinuities have previously been observed in linear Arrhenius plots when a phase change occurs at a specific temperature in an enzyme.50 However, the curvature exhibited in the Arrhenius plot of m-2-m–Mg2(dobpdc) is unusual and suggests a progressive decrease in the adsorption kinetics as T → Tstep. The curved Arrhenius plot can potentially be explained by considering the entropy change in the reaction coordinate diagram in 51 Moving from left to right along the reaction coordinate in 2 is immobilized and the initially dynamic diamines are locked into ammonium carbamate chains. As the temperature increases, the entropic penalty for immobilizing CO2 increases and ultimately outweighs the enthalpic favorability of adsorption when T exceeds Tstep. Accordingly, the kinetic barrier of the rate-determining chemisorption step should become increasingly large at higher temperatures, consequently slowing the reaction kinetics. Therefore, increasing the temperature towards Tstep imposes two compounding deleterious entropic effects on the rate of adsorption in m-2-m–Mg2(dobpdc): it thermodynamically disfavors the formation of the intermediate species (as discussed above), and it increases the magnitude of the rate-limiting kinetic barrier. Together, these effects can potentially explain the observed progressively slower adsorption kinetics and resulting curved Arrhenius plot as T approaches Tstep. Determining the identity of the intermediate species and elucidating the mechanism of the rate-limiting chemisorption process remain active areas of investigation.While the reaction coordinate diagram in 2(dobpdc) to other diamine-appended frameworks, we evaluated the kinetics of CO2 adsorption from a gas stream of 15% CO2 in N2 by a panel of Mg2(dobpdc) variants appended with structurally-diverse alkylethylenediamines. Notably, frameworks with 1°,3° alkylethylenediamines26 displayed minimal adsorption at temperatures ≥40 °C  and N,N′-diethylethylenediamine (e-2-e) exhibit two-step adsorption behavior,28 and thus their kinetic profiles are complex at temperatures at which both steps are operative. As a result, To determine the generalizability of these characteristics for m-2-m–Mg Fig. S12 and thus Fig. S12. We note2 by the same mechanism.26,52 In each case, kA increases with decreasing temperature, indicative of inverse Arrhenius behavior, as observed for m-2-m–Mg2(dobpdc)  represents a general feature of these materials. In kAvs. T data yield different x intercepts for each diamine-appended framework, reflecting their different adsorption step temperatures. The x-intercepts all match closely to step temperatures determined by cooling the frameworks under 15% CO2 , for which the kAvs. T plot deviates from linearity at high temperatures  is different for each material at a constant temperature. To account for this difference, we also plotted kAvs. Tstep − T to scale the x-intercepts of the linear fits to zero  functionalized with the 1°,2° diamines N-methylethylenediamine (m-2), N-ethylethylenediamine (e-2), and i-2.26,28,55 We previously determined that the primary amine preferentially binds to the metal site and reacts with CO2, which may account for the slower adsorption kinetics in these materials compared to those functionalized with 2°,2° diamines.26 However, this effect also bestows 1°,2° diamine-appended variants with enhanced stability toward diamine loss.26,28 The compounds with the least sterically-encumbered 1°,2° diamines exhibit slightly faster kinetics, as indicated by steeper slopes in the plots of kAvs. T  variants appended with the 1°,1° diamines ethylenediamine (en) and (±)-trans-diaminocyclohexane (dach),26,29,31,56 which have previously been shown to exhibit significant adsorption/desorption hysteresis and unit cell contraction upon CO2 adsorption.56 Interestingly, the CO2 adsorption kinetics of en–Mg2(dobpdc) are extremely similar to those of i-2–Mg2(dobpdc)—the 1°,2° variant with the slowest CO2 adsorption kinetics—while (±)-trans-dach–Mg2(dobpdc) exhibits much slower kinetics. In addition, (±)-trans-dach–Mg2(dobpdc) displays an unusually high nA of ∼3 at temperatures close to the step, corresponding to a very long induction period  become much faster and the induction periods become much shorter at lower temperatures  also shortens the induction period for this material -trans-dach–Mg2(dobpdc) is the unit cell contraction that occurs upon CO2 adsorption in conjunction with crystallographically characterized ion-pairing interactions between neighboring ammonium carbamate chains in the ab plane.56 Intriguingly, nA = 3 for the Avrami model corresponds to the growth of a crystal in two dimensions, whereas nA = 2 corresponds to growth in one dimension.44,45 Accordingly, cooperative CO2 adsorption in (±)-trans-dach–Mg2(dobpdc) may be akin to two-dimensional sheet growth, whereas cooperative CO2 capture by the other variants may be more akin to one-dimensional chain growth. Elucidating the potential correlation between ab plane contraction and the CO2 adsorption kinetics for 1°,1° diamine–Mg2(dobpdc) variants remains a subject of investigation.Finally, we studied the behavior of Mg Fig. S22. One pos2(dobpdc) has also been appended with diaminopropanes to yield cooperative adsorbents.27 For example, dmpn–Mg2(dobpdc)  has a favorable adsorption step temperature for CO2 capture from coal flue gas and maintains a high working capacity over 1000 cycles under humid conditions.27 Notably, the complex CO2 chemisorption mechanism in dmpn–Mg2(dobpdc) ultimately leads to the formation of carbamic acids interacting with ammonium carbamates, and this material exhibits a mixture of ∼4 chemisorbed species in the early stages of CO2 adsorption.52 Given this complexity and the promising attributes of dmpn–Mg2(dobpdc) for implementation in practical processes, we sought to investigate its adsorption kinetics from a gas stream of 15% CO2 in N2.In addition to ethylenediamines, Mg2 adsorption isobar for this material exhibits a step around 60 °C that is more broad than those of other diamine–appended Mg2(dobpdc) variants, reflecting its complex adsorption mechanism  is distinct from that of the other diamine-appended variants (2(dobpdc) exhibits a very rapid initial uptake, followed by slower uptake until reaching equilibrium. This unusual curve shape results in Avrami fits with small nA (∼0.4–0.7) and kA (∼0.003–0.006 s−1) values  occurs at 35 °C—the lowest temperature investigated—but only up to an occupancy of ∼0.6, after which the kinetics slow  is promising for implementation in a CO2 capture process.Consistent with previous findings, the 15% COechanism .27,52 Sivariants , with no Fig. S23. The fas Fig. S24. We note2 can be desorbed from diamine-appended Mg2(dobpdc) under a humidified stream of pure CO2 within less than 10 min, as limited by the heating rate of the TGA furnace.27,28 Alternatively, the introduction of dry N2 as a purge gas can be used to simulate the application of a concentration- or vacuum-swing process. Because diamine-appended Mg2(dobpdc) variants can maintain high CO2 capacities under pure CO2 even at relatively high temperatures, these materials can be heated under CO2 to a temperature of interest and allowed to equilibrate, after which the gas stream can be switched to dry N2 and the decrease in mass can be monitored.Desorption kinetics are also a critical consideration for the practical use of an adsorbent. In a typical fixed-bed process, adsorption and desorption stages are operated simultaneously using a minimum of two beds. As a consequence, fast desorption kinetics are desirable to minimize cycle times. In a simulation of the desorption conditions typical of a temperature swing adsorption process, we previously demonstrated that CO2 desorption assay to compare the desorption kinetics of dmpn–Mg2(dobpdc) and m-2-m–Mg2(dobpdc)  occurs in a lower temperature range compared to desorption from m-2-m–Mg2(dobpdc), reflecting the lower desorption step temperature for the dmpn variant of 93 °C 27 compared to 134 °C for m-2-m,26 as determined from dry 100% CO2 desorption isobars collected using a ramp rate of 1 °C min−1.We utilized this dry N(dobpdc) . At the 2(dobpdc) and m-2-m–Mg2(dobpdc) fit well to the Avrami model across multiple temperatures. For both materials, desorption is initially slow, but is accelerated after some CO2 has been desorbed. Interestingly, the desorption kinetics behavior of dmpn–Mg2(dobpdc) differs from its adsorption kinetics behavior. While this material exhibits no induction period for adsorption (nA ∼0.5), a substantial induction period was observed for desorption  exhibiting a mixture of approximately four chemisorbed species in the early stages of CO2 adsorption, while a 1 : 1 mixture of ammonium carbamates:carbamic acids is formed following saturation with CO2 and long equilibration times.52As shown in Fig. S25,2 adsorption kinetics of diamine-appended variants of the metal–organic framework Mg2(dobpdc) using a TGA-based assay. Sigmoidal kinetics profiles were observed for all of the materials that exclusively form ammonium carbamate chains upon CO2 adsorption, which we attribute to their cooperative adsorption mechanism. While these adsorbents exhibit long induction periods at temperatures near the adsorption step, the kinetics of adsorption can be accelerated and the length of the induction period minimized by decreasing the adsorption temperature. Additionally, the diamine structure can be optimized to yield adsorption thermodynamics and kinetics that are most favorable for a target gas separation involving CO2. Finally, no induction period was observed for the material dmpn–Mg2(dobpdc), which adsorbs CO2via a mixed ammonium carbamate/carbamic acid mechanism. Thus, accessing new chemisorption products within the diamine-appended materials may give rise to advantageous changes in kinetics as well as thermodynamics. Overall, this study provides key guidelines for utilizing diamine-appended variants of Mg2(dobpdc) in CO2 separations and should prove more broadly useful for the design of new chemisorptive adsorbents for carbon capture applications.The foregoing results describe a systematic investigation into the CO2 capture applications. The University of California, Berkeley has applied for a patent on some of the materials discussed herein, on which J. R. L., P. J. M., and R. L. S. are listed as inventors.The authors declare the following competing financial interest: J. R. L. has a financial interest in Mosaic Materials, Inc., a start-up company working to commercialize metal–organic frameworks for gas separations, including COSC-011-D0SC01087A-s001


Video has become the most popular medium of communication over the past decade, with nearly 90 percent of the bandwidth on the Internet being used for video transmission. Thus, evaluating the quality of an acquired or compressed video has become increasingly important. The goal of video quality assessment (VQA) is to measure the quality of a video clip as perceived by a human observer. Since manually rating every video clip to evaluate quality is infeasible, researchers have attempted to develop various quantitative metrics that estimate the perceptual quality of video. In this paper, we propose a new region-based average video quality assessment (RAVA) technique extending image quality assessment (IQA) metrics. In our experiments, we extend two full-reference (FR) image quality metrics to measure the feasibility of the proposed RAVA technique. Results on three different datasets show that our RAVA method is practical in predicting objective video scores. Video is widely used in our daily lives. TV shows, computer games, online meetings, all rely on the quality of video. As mentioned in , video sIn the real world, objects are three-dimensional (3D). To measure the perceptual quality, many aspects need to be considered. Resolutions of texture and mesh are combined to measure 3D perceptual quality in ; optimizThere are many image quality assessment (IQA) methods. For instance, SSIM  and PSNRFor evaluation, we used the LIVE Mobile VQA database , the MCLThe contributions of our paper are: (1) proposing a region-based VQA method that estimates video quality by extracting and processing the information of background regions and moving objects in the foreground regions; (2) integrating a self-supervised video content distinction network to generalize the VQA scores for videos with different content; (3) extending two full-reference IQA metrics to VQA metrics in the experiments, which shows the possibility of applying the RAVA technique to other FR IQA methods.Objective video quality assessment techniques can be categorized into three types: full reference (FR) methods, reduced reference (RR) methods and no reference (NR) methods. FR methods utilize the entire original video to determine the quality score. Nevertheless, their performance is relatively poor in terms of accuracy. Thus, perceptual factors in the human visual system (HVS) need to be incorporated to develop reliable video quality assessment techniques . Some FRNetflix proposed video multi-method assessment fusion (VMAF)  in 2016.RR methods extract some outstanding features from both the original and acquired videos, compare these features and obtain the objective score. For example, the Institute for Telecommunication Science (ITS) proposed the video quality metric (VQM) . It was h and v represent the horizontal and vertical axes, respectively; Here,  feature .NR methods access the quality of a new video without referring to the original video. Li et al.  proposedThe problem for existing FR and RR methods is that they do not working well if the content of videos in a dataset varies a lot. The correlation values of many existing FR and RR VQA scores with human perception are low. For the NR methods, the predicted quality tends to be more affected by the content than the distortions. NR methods are often trained and tested with in-the-wild video datasets. The videos there are collected from real-world video sequences. The content does vary significantly, but we are not sure how much distortion is involved.Since we want to extend some image quality assessment metrics to video, we will introduce the two full-reference IQA metrics we used below.PSNRPeak signal-to-noise ratio (PSNR)  is the rSSIMx, y, x, y, x and y, L is the dynamic range of the pixel-values . Instead, as mentioned above, we use the means and ranges of the intermediate scores to be the content distinction features. The implementation details are discussed in In recent years, machine-learning algorithms became popular for feature pooling, as they can consider the strength of those features and assign different weights. For instance, both the full-reference VQA method VMAF ,27 and tThe proposed RAVA methods were evaluated on two existing datasets: the LIVE Mobile Video Quality Assessment (VQA) Database  and the The MCL-V database contains 12 uncompressed HD (1920 * 1080) source video clips, as shown in The Netflix Public Dataset is a full-reference video quality assessment dataset published by Netflix together with their work ,27. It cioned in . HoweverThere do exist some advanced object detection and tracking methods such as AdaMM  and contThe features are called “content distinction”; thus, regardless of the distortion type, the video with the same content should obtain the same features. We used the Adam optimizer with a fixed learning rate of 0.0005 for 20 epochs to train the models. We perform cross-dataset prediction when we generated the content distinction features. This means that we trained the content distinction network on one dataset and predicted features on another dataset. In this case, the contents that we learned and tested were quite different. Our experimental results show that this is a promising direction.C are the two parameters to be tuned. C is used to control the regularization term. There are two common techniques for parameter tuning, namely grid search and random search. Both can help tune the hyper-parameters by trying different values and picking the one with the best performance. However, since random search randomly tries potential values, it can miss the best values. Thus, we used grid search.The SVR models on the LIVE mobile database and the MCL-V database are separately tuned since one dataset provides MOS and the other provides DMOS. For each dataset, we perform a random train–test split: 80% of the data train the SVR model, and the remaining data are used for testing. We calculated the average PCC and SCC over 100 runs. Each run has a different random seed. This can reduce the effect of some special cases and show off the overall performance. X and Y. PCC evaluates the linear relationship while SCC evaluates the monotonic relationship. Mathematically, PCC can be written asX and Y, respectively; We used Pearson’s (linear) correlation coefficient (PCC)  and Spean for both X and Y, X sample. Similarly, For SCC, given two samples of size RAVA scores and MOS or DMOS may increase by very different factors. In this case, the PCC value will be affected. However, since SCC is calculated based on the ranks, the value for SCC will remain the same even if they change at different rates. Taking this into consideration, we also reported the SCC scores. In addition, the correlation coefficients are in range of −1–1 since the RAVA scores and the ground truth scores may go in different directions. We only want to measure how strongly the two variables are correlated. Thus, we will only compare the absolute value of PCC and SCC values. If the absolute value is large, then their correlation is high; otherwise, they are less likely to be correlated. The new metric is still considered to be valuable if the negative correlation is strong.C for the LIVE mobile database and the MCL-V database.We first analyzed the SCC and PCC on the mobile DMOS for the LIVE Mobile Video Quality Assessment (VQA) Database. To better visualize the results for different distortion types, we drew the scatter plots of the RAVA scores vs. DMOS in From all the plots, we can see that the performance of the two proposed FR VQA methods RAVAds: PSNR ; VQM 52], we ax is the objective VQA score.In The two RAVA methods perform better in the LIVE Mobile database than in the MCL-V database. This is due to the limitations of the training data for MCL-V’s content distinction network. We trained the model with the LIVE Mobile database, but that dataset only contains real-life video clips. Thus, the trained model is not good at predicting the cartoons and animations which are in the MCL-V database.We also conducted cross-library validation on the Netflix Public Dataset  using thWe introduced a new video quality evaluation approach that integrated various image quality assessment methods, namely region-based detection, temporal weights from optical flow, and content distinction features. Our RAVA technique was applied to extend two full-reference IQA metrics. We first separated foreground and background regions for all the video frames. Then, we integrated the motion features into the weights while designing the VQA metrics. The region weights were defined as the percentage of the average magnitudes of the optical flows for those regions out of all the regions. The foreground feature was the weighted average of the foreground IQA scores, and the background feature was the simple average of background IQA scores. Furthermore, a content distinction network was added to generalize the RAVA scores for videos with various types of content. All the features were passed to an SVR model to predict the final VQA score. We tested on two different datasets to validate the RAVA technique. The LIVE Mobile VQA database and the MCL-V database are widely used VQA datasets, so we used them to compare the performance of the RAVA methods with existing methods. By analyzing the correlation of the RAVA scores and the DMOS (or MOS) provided by the datasets, we noticed that RAVAIn summary, we believe that the RAVA approach has practical significance. It can extend IQA methods to VQA methods, and we expect it to be widely applicable for video quality assessment in the future.