Frontal Polymerization for the Rapid Obtainment of Polymer Composites.

Among the different polymerization techniques, frontal polymerization (FP) has gained high interest from the scientific community because of its peculiar characteristics: in particular, compared to classic polymerization reactions, FP allows for a better exploitation of the heat of polymerization involved, without requiring any external energy input apart from an initial photo or thermal ignition that triggers the reaction. The latter usually propagates in a few tenths of seconds or (at most) minutes through a hot self-sustaining polymerization front, giving rise to the formation of fully cured thermosetting networks or thermoplastic polymers. Furthermore, different polymerization mechanisms can be involved in FP reactions, comprising cationic or anionic, ring-opening metathesis, and free-radical polymerization, among others. Further, it is possible to run FP reactions in bulk, in solution, or even using solid monomers if they are melted at the temperature of the front, notwithstanding the possibility of using reactive systems containing fillers or fiber/fabric reinforcements. In this context, the use of FP is becoming very important also for the design and production of advanced (nano)composite materials, saving processing time and achieving the completeness of the curing reaction, even in the presence of high filler/reinforcement loadings. Therefore, this mini-review aims to provide the reader with the basics of FP and its main peculiarities, even in the context of preparing high-performing composites. In this respect, some recent case studies witnessing the potentialities of frontal polymerization for the design of advanced (nano)composite systems will be elucidated. Finally, some perspectives about possible future developments will be proposed.

Same-session endoscopic diagnosis and symptom palliation in pancreato-biliary malignancies: Clinical impact of rapid on-site evaluation (ROSE).

Background and study aims Besides increasing adequacy, rapid on-site evaluation (ROSE) during endoscopic ultrasound (EUS) or endoscopic retrograde cholangiopancreatography (ERCP) may impact choices and timing of subsequent therapeutic procedures, yet has been unexplored. Patients and methods This was a retrospective evaluation of a prospectively maintained database of a tertiary, academic centre with availability of ROSE and hybrid EUS-ERCP suites. All consecutive patients referred for pathological confirmation of suspected malignancy and jaundice or gastric outlet obstruction (GOO) between Jan-2020 and Sep-2022 were included. Results Of 541 patients with underlying malignancy, 323 (59.7%) required same-session pathological diagnosis (male: 54.8%; age 70 [interquartile range 63-78]; pancreatic cancer: 76.8%, biliary tract adenocarcinoma 16.1%). ROSE adequacy was 96.6%, higher for EUS versus ERCP. Among 302 patients with jaundice, ERCP-guided stenting was successful in 83.1%, but final drainage was completed in 97.4% thanks to 43 EUS-guided biliary drainage procedures. Twenty-one patients with GOO were treated with 15 EUS-gastroenterostomies and six duodenal stents. All 58 therapeutic EUS procedures occurred after adequate ROSE. With ERCP-guided placement of stents, the use of plastic stents was significantly higher among patients with inadequate ROSE (10/11; 90.9%) versus adequate sampling (14/240; 5.8%) P <0.0001; OR 161; 95%CI 19-1352). Median hospital stay for diagnosis and palliation was 3 days (range, 2-7) and median time to chemotherapy was 33 days (range, 24-47). Conclusions Nearly two-thirds of oncological candidates for endoscopic palliation require contemporary pathological diagnosis. ROSE adequacy allows, since the index procedure, state-of-the-art therapeutics standardly restricted to pathologically confirmed malignancies (e.g. uncovered SEMS or therapeutic EUS), potentially reducing hospitalization and time to oncological treatments.

Polymer Hydrogels and Frontal Polymerization: A Winning Coupling.

Polymer hydrogels are 3D networks consisting of hydrophilic crosslinked macromolecular chains, allowing them to swell and retain water. Since their invention in the 1960s, they have become an outstanding pillar in the design, development, and application of engineered polymer systems suitable for biomedical and pharmaceutical applications (such as drug or cell delivery, the regeneration of hard and soft tissues, wound healing, and bleeding prevention, among others). Despite several well-established synthetic routes for developing polymer hydrogels based on batch polymerization techniques, about fifteen years ago, researchers started to look for alternative methods involving simpler reaction paths, shorter reaction times, and lower energy consumption. In this context, frontal polymerization (FP) has undoubtedly become an alternative and efficient reaction model that allows for the conversion of monomers into polymers via a localized and propagating reaction-by means of exploiting the formation and propagation of a "hot" polymerization front-able to self-sustain and propagate throughout the monomeric mixture. Therefore, the present work aims to summarize the main research outcomes achieved during the last few years concerning the design, preparation, and application of FP-derived polymeric hydrogels, demonstrating the feasibility of this technique for the obtainment of functional 3D networks and providing the reader with some perspectives for the forthcoming years.

α-Glucosidase inhibition by green, white and oolong teas: in vitro activity and computational studies.

Natural α-glucosidase inhibitors from plant-based foods such as catechins offer an attractive strategy for their potential anti-diabetic effects. In this study, infusions of three different tea types (green, white, and oolong) were investigated for their total phenolic (TPC) and catechins (EGCG, ECG, EGC, and EC) content, and for their α-glucosidase inhibitory activities. We observed that the level of TPC in white tea was significantly higher compared to oolong and green tea, which suggests higher content of EGCG and ECG catechins in fresh young leaves. Our findings showed that the higher content of such catechins in the infusion of white tea well correlated with a strong inhibition of α-glucosidase, and such inhibition was demonstrated to be more effective than the FDA-approved drug acarbose. Then, we computationally explored the molecular requirements for enzyme inhibition, especially for the most active catechins EGCG and ECG, as well as their disposition/stability within the active site.

Endoscopic and Surgical Management of Non-Metastatic Ampullary Neuroendocrine Neoplasia: A Multi-Institutional Pancreas2000/EPC Study.

INTRODUCTION: Ampullary neuroendocrine neoplasia (NEN) is rare and evidence regarding their management is scarce. This study aimed to describe clinicopathological features, management, and prognosis of ampullary NEN according to their endoscopic or surgical management. METHODS: From a multi-institutional international database, patients treated with either endoscopic papillectomy (EP), transduodenal surgical ampullectomy (TSA), or pancreaticoduodenectomy (PD) for ampullary NEN were included. Clinical features, post-procedure complications, and recurrences were assessed. RESULTS: 65 patients were included, 20 (30.8%) treated with EP, 19 (29.2%) with TSA, and 26 (40%) with PD. Patients were mostly asymptomatic (n = 46; 70.8%). Median tumor size was 17 mm (12-22), tumors were mostly grade 1 (70.8%) and pT2 (55.4%). Two (10%) EP resulted in severe American Society for Gastrointestinal Enterology (ASGE) adverse post-procedure complications and 10 (50%) were R0. Clavien 3-5 complications did not occur after TSA and in 4, including 1 postoperative death (15.4%) of patients after PD, with 17 (89.5%) and 26 R0 resection (100%), respectively. The pN1/2 rate was 51.9% (n = 14) after PD. Tumor size larger than 1 cm (i.e., pT stage >1) was a predictor for R1 resection (p < 0.001). Three-year overall survival and disease-free survival after EP, TSA, and PD were 92%, 68%, 92% and 92%, 85%, 73%, respectively. CONCLUSION: Management of ampullary NEN is challenging. EP should not be performed in lesions larger than 1 cm or with a endoscopic ultrasonography T stage beyond T1. Local resection by TSA seems safe and feasible for lesions without nodal involvement. PD should be preferred for larger ampullary NEN at risk of nodal metastasis.

Frontal Polymerizations: From Chemical Perspectives to Macroscopic Properties and Applications.

The synthesis and processing of most thermoplastics and thermoset polymeric materials rely on energy-inefficient and environmentally burdensome manufacturing methods. Frontal polymerization is an attractive, scalable alternative due to its exploitation of polymerization heat that is generally wasted and unutilized. The only external energy needed for frontal polymerization is an initial thermal (or photo) stimulus that locally ignites the reaction. The subsequent reaction exothermicity provides local heating; the transport of this thermal energy to neighboring monomers in either a liquid or gel-like state results in a self-perpetuating reaction zone that provides fully cured thermosets and thermoplastics. Propagation of this polymerization front continues through the unreacted monomer media until either all reactants are consumed or sufficient heat loss stalls further reaction. Several different polymerization mechanisms support frontal processes, including free-radical, cat- or anionic, amine-cure epoxides, and ring-opening metathesis polymerization. The choice of monomer, initiator/catalyst, and additives dictates how fast the polymer front traverses the reactant medium, as well as the maximum temperature achievable. Numerous applications of frontally generated materials exist, ranging from porous substrate reinforcement to fabrication of patterned composites. In this review, we examine in detail the physical and chemical phenomena that govern frontal polymerization, as well as outline the existing applications.

Machine learning for the prediction of post-ERCP pancreatitis risk: A proof-of-concept study.

BACKGROUND: Predicting Post-Endoscopic Retrograde Cholangiopancreatography (ERCP) pancreatitis (PEP) risk can be determinant in reducing its incidence and managing patients appropriately, however studies conducted thus far have identified single-risk factors with standard statistical approaches and limited accuracy. AIM: To build and evaluate performances of machine learning (ML) models to predict PEP probability and identify relevant features. METHODS: A proof-of-concept study was performed on ML application on an international, multicenter, prospective cohort of ERCP patients. Data were split in training and test set, models used were gradient boosting (GB) and logistic regression (LR). A 10-split random cross-validation (CV) was applied on the training set to optimize parameters to obtain the best mean Area Under Curve (AUC). The model was re-trained on the whole training set with the best parameters and applied on test set. Shapley-Additive-exPlanation (SHAP) approach was applied to break down the model and clarify features impact. RESULTS: One thousand one hundred and fifty patients were included, 6.1% developed PEP. GB model outperformed LR with AUC in CV of 0.7 vs 0.585 (p-value=0.012). GB AUC in test was 0.671. Most relevant features for PEP prediction were: bilirubin, age, body mass index, procedure time, previous sphincterotomy, alcohol units/day, cannulation attempts, gender, gallstones, use of Ringer's solution and periprocedural NSAIDs. CONCLUSION: In PEP prediction, GB significantly outperformed LR model and identified new clinical features relevant for the risk, most being pre-procedural.

Transparent Wood-Based Materials: Current State-of-the-Art and Future Perspectives.

Human history is largely characterized by the massive use of wood, the most well-known natural composite material, possessing unique thermal, mechanical, and environmental features that make it suitable for several applications, ranging from civil engineering, art, and household uses, to business uses (including furniture, stationery, shipbuilding, and fuel). Further, as a renewable and recyclable biomass, wood perfectly matches the current circular economy concept. However, because of its structure and composition, wood is not transparent: therefore, the possibility of removing the embedded lignin, hence limiting the light-scattering phenomena, has been investigated over the last ten to fifteen years, hence obtaining the so-called "transparent wood (TW)". This latter represents an up-to-date key material, as it can be utilized as obtained or further functionalized, combining the transparency with other features (such as flame retardance, energy storage ability, and environmental protection, among others), which widen the potential (and practical) applications of wood. The present manuscript aims at summarizing first the current methods employed for obtaining transparent wood, and then the latest achievements concerning the properties of transparent wood, providing the reader with some perspectives about its novel functionalizations and applications.

Risk factors for the occurrence of ampullary tumors: A case-control study.

BACKGROUND: The incidence of ampullary tumors is increasing but data on association with an increased exposure to certain risk factors are scanty. OBJECTIVE: To investigate risk and protective factors associated with the occurrence of ampullary tumors and whether these factors differ between ampullary tumors of the intestinal and pancreatobiliary subtypes or between adenomas and carcinomas. METHODS: The association between a large set of exposome features and ampullary tumors occurrence was investigated in a bi-centric case-control study after ethic committee approval and power calculation. RESULTS: In 223 histologically confirmed patients and 446 controls, previous cholecystectomy (odd ratio [OR] = 2.07; 95% confidence interval [CI] = 1.34-3.20) and proton pump inhibitors use (OR = 1.66; 95% CI = 1.16-2.37) were associated with increased risk of ampullary tumors, aspirin use (OR = 0.57; 95% CI = 0.36-0.90) and light alcohol intake (OR = 0.54; 95% CI = 0.38-0.76) with reduced risk. A previous cholecystectomy was also associated with tumors of intestinal subtype and with both adenomas and carcinomas, and proton pump inhibitors use with adenomas only. Smoking, body mass index, family history of cancers, previous ulcer, diabetes and use of statins, insulin and metformin were not significant factors. CONCLUSION: This is the first case-control study specifically highlighting factors associated with the occurrence of ampullary tumors. We report factors that are novel and plausible, in keeping with mechanisms described for other gastrointestinal tumors and with potential clinical relevance.

Overview of the retina and imaging in patients with severe acute respiratory syndrome coronavirus 2.

INTRODUCTION: The role of the human eye in severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is still under investigation. The pathophysiology of the ocular findings is arduous when dealing with critically ill Covid-19 patients with comorbidities. Multiorgan involvement and the effects of inflammation, infection and systemic treatment on the retina are complex, and comparison of studies is difficult. Most studies in human patients have investigated the anterior segment, whereas few reports deal with the posterior segment of the eye. The present review aims to evaluate the retinal manifestations and imaging features in COVID-19 patients. METHODS: Studies on the retinal manifestations and retinal imaging in COVID-19 patients published through June 2021 were reviewed. We included cross-sectional and case-control studies, case series, case reports and correspondence in the analysis. RESULTS: Flame-shaped hemorrhages, cotton wool spots, augmented diameter and tortuosity of retinal vessels were found on funduscopic examination. Peripapillary, macular retinal nerve fiber layer and ganglion cell layer thickness alterations were reported on spectral domain optical coherence tomography. Reduced vessel density of the superficial and deep retinal capillary plexus on optical coherence tomography angiography was reported. CONCLUSIONS: Retinal complications may arise in COVID-19 patients. Although no consensus on presentation is currently available, retinal funduscopy and imaging has shown neuronal and vascular alterations. Systemic neurological complications and microangiopathy are associated with SARS-COV-2; thus, as the retina has a neuronal and vascular component, funduscopy and retinal imaging on COVID-19 patients can provide further insight to SARS-COV-2 disease and the follow-up of patients.

Digital single-operator cholangioscopy in diagnostic and therapeutic bilio-pancreatic diseases: A prospective, multicenter study.

BACKGROUND AND AIM: Digital single-operator cholangioscopy (D-SOC) is an endoscopic procedure that is increasingly used for the management of bilio-pancreatic diseases. We aimed to investigate the efficacy and safety of D-SOC for diagnostic and therapeutic indications. METHODS: This is a multicenter, prospective study(January 2016-June 2019) across eighteen tertiary centers. The primary outcome was procedural success of D-SOC. Secondary outcomes were: D-SOC visual assessment and diagnostic yield of SpyBite biopsy in cases of biliary strictures, stone clearance rate in cases of difficult biliary stones, rate of adverse events(AEs) for all indications. RESULTS: D-SOC was performed in 369 patients (201(54,5%) diagnostic and 168(45,5%)therapeutic). Overall, procedural success rate was achieved in 360(97,6%) patients. The sensitivity, specificity, PPV, NPV and accuracy in biliary strictures were: 88,5%, 77,3%, 83,3%, 84,1% and 83,6% for D-SOC visual impression; 80,2%, 92,6%, 95,1%, 72,5% and 84,7% for the SpyBite biopsy, respectively. For difficult biliary stones, complete duct clearance was obtained in 92,1% patients (82,1% in a single session). Overall, AEs occurred in 37(10%) cases.The grade of AEs was mild or moderate for all cases, except one which was fatal. CONCLUSION: D-SOC is effective for diagnostic and therapeutic indications.Most of the AEs were minor and managed conservatively, even though a fatal event has happened that is not negligible and should be considered before using D-SOC.

Comparative Evaluation of Graphene Nanostructures in GERS Platforms for Pesticide Detection.

Graphene-enhanced Raman scattering (GERS) produces enhancement of the Raman signal, which is based on chemical rather than electromagnetic mechanism such as in the surface-enhanced Raman scattering. Graphene oxide, amino- and guanidine-functionalized graphene oxide, exfoliated graphene, and commercial graphene nanoplatelets have been used to investigate the GERS response with the change of graphene properties. Different graphene nanostructures have been embedded into organic-inorganic microporous films to build a platform for the fast and sensitive detection of pesticides in water. The graphene nanostructures vary in the number of layers, lateral size, degree of oxidation, and surface functionalization. The GERS performances of the graphene nanostructures cast on silicon substrates and embedded in the nanocomposite films have been comparatively evaluated. After casting a few droplets of the pesticide aqueous solution on the graphene nanostructures, the Raman band enhancements of the analytes have been measured. In the nanocomposite films, the characteristic Raman bands originating from pesticides such as paraoxon, parathion, and glyphosate could be traced at concentrations below 10-7, 10-5, and 10-4 M, respectively. The results show that the surface functionalization reduces the GERS effect because it increases the ratio between the sp3 carbon and sp2 carbon. On the other hand, the comparison among different types of graphenes shows that the monolayers are more efficient than the few-layer nanostructures in enhancing the Raman signal.

A multicenter survey on endoscopic retrograde cholangiopancreatography during the COVID-19 pandemic in northern and central Italy.

Background and study aims COVID-19 has dramatically impacted endoscopy practice because upper endoscopy procedures can be aerosol-generating. Most elective procedures have been rescheduled. Endoscopic retrograde cholangiopancreatography (ERCP) is frequently performed in emergency or urgent settings in which rescheduling is not possible. We evaluated the impact of the COVID-19 pandemic on ERCP in Italy during the SARS-CoV-2 lockdown, in areas with high incidence of COVID-19. Patients and methods We performed a retrospective survey of centers performing ERCP in high COVID-19 prevalence areas in Italy to collect information regarding clinical data from patients undergoing ERCP, staff, case-volume and organization of endoscopy units from March 8, 2020 to April 30, 2020. Results We collected data from 31 centers and 804 patients. All centers adopted a triage and/or screening protocol for SARS-CoV-2 and performed follow-up of patients 2 weeks after the procedure. ERCP case-volume was reduced by 44.1 % compared to the respective 2019 timeframe. Of the 804 patients undergoing ERCP, 22 (2.7 %) were positive for COVID-19. Adverse events occurred at a similar rate to previously published data. Of the patients, endoscopists, and nurses, 1.6 %, 11.7 %, and 4.9 %, respectively, tested positive for SARS-CoV-2 at follow up. Only 38.7 % of centers had access to a negative-pressure room for ERCP. Conclusion The case-volume reduction for ERCP during lockdown was lower than for other gastrointestinal endoscopy procedures. No definitive conclusions can be drawn about the percentage of SARS-CoV-2-positive patients and healthcare workers observed after ERCP. Appropriate triage and screening of patients and adherence to society recommendations are paramount.

Factors associated with risk of COVID-19 contagion for endoscopy healthcare workers: A survey from the Italian society of digestive endoscopy.

BACKGROUND AND AIMS: The present study was aimed to assess the risk of SARS-CoV-2 infection and associated factors among HCWs in endoscopy centers in Italy. METHODS: All members of the Italian Society of Digestive Endoscopy (SIED) were invited to participate to a questionnaire-based survey during the first months of the COVID-19 outbreak in Italy. RESULTS: 314/1306 (24%) SIED members accounting for 201/502 (40%) endoscopic centers completed the survey. Personal Protection Equipment (PPE) were available in most centers, but filtering face-piece masks (FFP2 or FFP3) and negative pressure room were not in 10.9 and 75.1%. Training courses on PPE use were provided in 57.2% of centers only; there was at least one positive HCW in 17.4% of centers globally, 107/3308 (3.2%) HCWs were diagnosed with COVID-19 with similar rates of physicians (2.9%), nurses (3.5%) and other health operators (3.5%). Involvement in a COVID-19 care team (OR: 4.96) and the lack of training courses for PPE, (OR: 2.65) were associated with increased risk. CONCLUSIONS: The risk of COVID-19 among endoscopy HCWs was not negligible and was associated with work in a COVID-19 care team and lack of education on proper PPE use. These data deserve attention during the subsequent waves.

High sensitivity of ROSE-supported ERCP-guided brushing for biliary strictures.

Background and study aims Endoscopic retrograde cholangiopancreatography (ERCP) plays a major role in biliary strictures, with brushing being a cheap and fast method to acquire a cytological specimen, despite a sensitivity around 45 %. Rapid on-site evaluation (ROSE) is widely used for endoscopic ultrasound-acquired cytological specimen adequacy, improving its sensitivity and specificity. Nevertheless, no study has evaluated its role for ERCP-guided brushing. Our aim was to assess the diagnostic yield of ERCP-guided brushing of biliary strictures when supported by ROSE. Patients and methods This was a retrospective single-center study that included patients undergoing ERCP-guided brush cytology supported by ROSE for biliary strictures. Recorded data included patient clinical-radiological and ERCP features. Final diagnosis was determined after surgery, intraductal biopsy or adequate follow-up. The diagnostic yield was calculated and a subgroup analysis for factors associated with false-negative or true-positive results was performed. Results Two hundred six patients were included, 57.3 % males, median age 72 years, 77.2 % having extrahepatic biliary strictures. Of the patients, 99 % had an adequate sample at ROSE after a mean of 2.6 passages. The diagnostic yield was accuracy 83 %, sensitivity 74.6 %, and specificity 98 %, positive and negative predictive values 98 % and 71 % respectively, with an area under the curve of 0.86. A diagnosis of cholangiocarcinoma was significantly more frequent among true-positive cases (68 % vs 46.8 %; P  = 0.04). Conclusions This is the first study evaluating the use of ROSE as support for ERCP-guided brushing of biliary strictures, with a sensitivity far higher than those reported for brushing alone and at least comparable to those of more expensive and invasive techniques.

Chronic use of statins and acetylsalicylic acid and incidence of post-endoscopic retrograde cholangiopancreatography acute pancreatitis: A multicenter, prospective, cohort study.

OBJECTIVES: Post-endoscopic retrograde cholangiopancreatography (ERCP) acute pancreatitis (PEP) is a frequent complication of this endoscopic procedure. Chronic statin intake has been linked to lower incidence and severity of acute pancreatitis (AP). Periprocedural rectal administration of non-steroidal anti-inflammatory drugs is protective against PEP, but the role of chronic acetylsalicylic acid (ASA) treatment is unclear. We aimed to investigate whether statins and chronic ASA intake are associated with lower risk of PEP. METHODS: An international, multicenter, prospective cohort study. Consecutive patients undergoing ERCP in seven European centers were included. Patients were followed-up to detect those with PEP. Multivariate analysis by means of binary logistic regression was performed, and adjusted odds ratios (aORs) were calculated. RESULTS: A total of 1150 patients were included, and 70 (6.1%) patients developed PEP. Among statins users, 8.1% developed PEP vs. 5.4% among non-users (P = 0.09). Multivariate analysis showed no association between statin use and PEP incidence (aOR 1.68 (95% CI 0.94-2.99, P = 0.08)). Statin use had no effect on severity of PEP, being mild in 92.0% of statin users vs. 82.2% in non-statin users (P = 0.31). Chronic ASA use was not associated with PEP either (aOR 1.02 (95% CI 0.49-2.13), P = 0.96). Abuse of alcohol and previous endoscopic biliary sphincterotomy were protective factors against PEP, while >1 pancreatic guidewire passage, normal bilirubin values, and duration of the procedure >20 minutes, were risk factors. CONCLUSIONS: The use of statins or ASA is not associated with a lower risk or a milder course of PEP.