Ultrafast Self-Healing Elastomer with Closed-Loop Recyclability.

The loss of function after prolonged periods of use is inevitable for all materials including plastics. Hence, self-healing capabilities are a key development to prolong the service lifetime of materials. One of such self-healing capabilities can be achieved by integrating dynamic bonds such as boronic ester linkages into polymeric materials, however the rate of self-healing in these materials is insufficient and current methods to accelerate it are limited. In this study, we report the rational design, synthesis and characterization of a fluorinated elastomer (FBE15) that utilizes enhanced interaction between polymer chains afforded by strong dipole-dipole interactions from -CF3, which showed a significant increase in binding energy to -7.71 Kcal/mol from -5.51 Kcal/mol, resulting in increased interaction between the boronic ester linkages and improving self-healing capabilities of boronic ester materials, drastically reducing the time required for stress relaxation by 900 %. The bulk elastomer is capable of ultrafast self-healing in a one-click fashion that can happen in mere seconds, which can then be stretched to 150 % of its original length. By utilising the dynamic cross-linking, FBE15 is also capable of both mechanical reprocessing into the same materials and chemical recycling into its starting materials, respectively, further allowing reconstruction of the elastomers that have comparable properties to the original ones at the end of its service lifespan.

Recyclable, Malleable, and Strong Thermosets Enabled by Knoevenagel Adducts.

Plastic recycling is critical for waste management and achieving a circular economy, but it entails difficult trade-offs between performance and recyclability. Here, we report a thermoset, poly(α-cyanocinnamate) (PCC), synthesized using Knoevenagel condensation between terephthalaldehyde (TPA) and a triarm cyanoacetate star, that tackles this difficulty by harnessing its intrinsically conjugated and dynamic chemical characteristics. PCCs exhibit extraordinary thermal and mechanical properties with a typical Tg of ∼178 °C, Young's modulus of 3.8 GPa, and tensile strength of 102 MPa, along with remarkable flexibility and dimensional and chemical stabilities. Furthermore, end-of-life PCCs can be selectively degraded and partially recycled back into one starting monomer TPA for a new production cycle or reprocessed through dynamic exchange aided by cyanoacetate chain-ends. This study lays the scientific groundwork for the design of robust and recyclable thermosets, with transformative potential in plastic engineering.

Hydrogen Activation with Ru-PN3P Pincer Complexes for the Conversion of C1 Feedstocks.

The hydrogenation of C1 feedstocks (CO and CO2) has been investigated using ruthenium complexes [RuHCl(CO)(PN3P)] as the catalyst. PN3P pincer ligands containing amines in the linker between the central pyridine donor and the phosphorus donors with bulky substituents (tert-butyl (1) or TMPhos (2)) are required to obtain mononuclear single-site catalysts that can be activated by the addition of KOtBu to generate stable five-coordinate complexes [RuH(CO)(PN3P-H)], whereby the pincer ligand has been deprotonated. Activation of hydrogen takes place via heterolytic cleavage to generate [RuH2(CO)(PN3P)], but in the presence of CO, coordination of CO occurs preferentially to give [RuH(CO)2(PN3P-H)]. This complex can be protonated to give the cationic complex [RuH(CO)2(PN3P)]+, but it is unable to activate H2 heterolytically. In the case of the less coordinating CO2, both ruthenium complexes 1 and 2 are highly efficient as CO2 hydrogenation catalysts in the presence of a base (DBU), which in the case of the TMPhos ligand results in a TON of 30,000 for the formation of formate.

Surface antimicrobial functionalization with polymers: fabrication, mechanisms and applications.

Undesirable adhesion of microbes such as bacteria, fungi and viruses onto surfaces affects many industries such as marine, food, textile, and healthcare. In particular in healthcare and food packaging, the effects of unwanted microbial contamination can be life-threatening. With the current global COVID-19 pandemic, interest in the development of surfaces with superior anti-viral and anti-bacterial activities has multiplied. Polymers carrying anti-microbial properties are extensively used to functionalize material surfaces to inactivate infection-causing and biocide-resistant microbes including COVID-19. This review aims to introduce the fabrication of polymer-based antimicrobial surfaces through physical and chemical modifications, followed by the discussion of the inactivation mechanisms of conventional biocidal agents and new-generation antimicrobial macromolecules in polymer-modified antimicrobial surfaces. The advanced applications of polymer-based antimicrobial surfaces on personal protective equipment against COVID-19, food packaging materials, biomedical devices, marine vessels and textiles are also summarized to express the research trend in academia and industry.

Cardiopulmonary Exercise Testing in Stroke Rehabilitation: Benefits and Clinical Utility Perceived by Physiotherapists and Individuals with Stroke.

Purpose: The purpose of this study was to understand the perceived benefits and clinical utility of cardiopulmonary exercise testing (CPET) from the perspectives of physiotherapists and patients and to explore the factors that influence adopting CPET in a stroke rehabilitation setting. Method: A qualitative descriptive study was conducted. Physiotherapists (n = 6) participated in a focus group to discuss the use of CPET in practice. Patients (n = 8) who had completed CPET during stroke rehabilitation participated in a semi-structured interview to explore their experiences. Thematic analysis was performed. Results: CPET increased the physiotherapists' confidence in prescribing exercise, especially for medically complex patients. Ongoing medical management early post-stroke was a barrier to referral. Physiotherapists expressed decreased confidence in interpreting test results. Consultation with local experts facilitated the use of CPET. Patients described how CPET increased their confidence to participate in exercise. They desired more information before and after CPET to better understand the purpose and results and their relation to their rehabilitation goals. Conclusions: Both physiotherapists and patients described the benefit of having CPET available to support them as they participated in exercise in a stroke rehabilitation setting. Physiotherapists would benefit from having educational tools to support their interpretation and application of test results, and patients would benefit from improved communication and education to support their understanding of the relevance of CPET to their rehabilitation goals. Future research should explore these findings in other stroke rehabilitation settings.

Objectif : comprendre les avantages perçus et l'utilité clinique de l'épreuve d'effort cardiorespiratoire (ÉECR) du point de vue des physiothérapeutes et des patients et explorer les facteurs qui influent sur l'adoption de l'ÉECR dans un milieu de réadaptation après un accident vasculaire cérébral (AVC). Méthodologie : étude descriptive qualitative. Les physiothérapeutes (n = 6) ont participé à un groupe de travail pour discuter de l'utilisation de l'ÉECR dans la pratique. Les patients (n = 8) qui ont effectué une ÉECR pendant la réadaptation après un AVC ont participé à une entrevue semi-structurée pour explorer leurs expériences. Une analyse thématique a suivi. Résultats : l'ÉECR donne confiance aux physiothérapeutes qui prescrivent de l'exercice, particulièrement pour les patients qui éprouvent des problèmes de santé complexes. La prise en charge médicale continue peu après un AVC était un obstacle à une demande de consultation. Les physiothérapeutes exprimaient leur manque de confiance à interpréter les résultats de l'ÉECR. La consultation d'experts locaux les incitait à utiliser l'ÉECR. Les patients ont expliqué que l'ÉECR leur donnait confiance à participer aux exercices. Ils souhaitaient recevoir plus d'information avant et après l'ÉECR, afin de mieux comprendre la raison d'être, les résultats et leur lien avec les objectifs de réadaptation. Conclusion : les physiothérapeutes et les patients ont décrit les avantages de disposer de l'ÉECR pour les aider dans le cadre des exercices effectués en réadaptation après un AVC. Les physiothérapeutes profiteraient d'outils de formation pour les aider à interpréter et appliquer les résultats, et les patients profiteraient de meilleures communications et d'une meilleure éducation pour mieux comprendre la pertinence de l'ÉECR dans l'atteinte de leurs objectifs de réadaptation. Les prochaines recherches devraient explorer ces résultats dans d'autres milieux de réadaptation après un AVC.

Ambulatory Blood Pressure Monitoring in a Cohort of Children Referred with Suspected Hypertension: Characteristics of Children with and without Attention Deficit Hyperactivity Disorder.

Childhood hypertension's increasing prevalence has generally been linked to the obesity epidemic. We observed that a significant proportion of children referred to our pediatric center with documented office hypertension are nonobese and have a history of attention deficit hyperactivity disorder (ADHD). To define the extent of this anecdotal observation, we performed a retrospective analysis of ambulatory blood pressure monitoring (ABPM) tests which in our center are routinely performed in newly referred children suspected of hypertension. Twenty-one percent (48 of 227 new referrals) had a history of ADHD, and 81% of them were treated with psychostimulant medications at the time of their ABPM test. Children in this group had a significantly lower average BMI z-score compared with the rest of the children (0.18 versus 0.75) and were significantly more likely to have abnormally elevated wake systolic loads on ABPM (38% versus 4%). The overall proportion of children with any abnormality on ABPM was comparable in both groups (46% versus 40%). Conclusion. A significant proportion of children suspected of hypertension have ADHD which may be related to higher wake systolic BP values. The prevalence of hypertension among children with ADHD will have to be determined in prospective studies.