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Dynamic Interfacial Adhesion through Cucurbit[n]uril Molecular Recognition

Liu J, Tan CSY, Scherman OA

Angew Chem Int Ed Engl, 2018 07 16;57(29):8854-8858.
PMID: 29663607 DOI: 10.1002/anie.201800775

Supramolecular building blocks, such as cucurbit[n]uril (CB[n])-based host-guest complexes, have been extensively studied at the nano- and microscale as adhesion promoters. Herein, we exploit a new class of CB[n]-threaded highly branched polyrotaxanes (HBP-CB[n]) as aqueous adhesives to macroscopically bond two wet surfaces, including biological tissue, through the formation of CB[8] heteroternary complexes. The dynamic nature of these complexes gives rise to adhesion with remarkable toughness, displaying recovery and reversible adhesion upon mechanical failure at the interface. Incorporation of functional guests, such as azobenzene moieties, allows for stimuli-activated on-demand adhesion/de-adhesion. Macroscopic interfacial adhesion through dynamic host-guest molecular recognition represents an innovative strategy for designing the next generation of functional interfaces, biomedical devices, tissue adhesives, and wound dressings.
INR Control of Patients with Mechanical Heart Valve on Long-Term Warfarin Therapy

Tan CSY, Fong AYY, Jong YH, Ong TK

Glob Heart, 2018 12;13(4):241-244.
PMID: 30213574 DOI: 10.1016/j.gheart.2018.08.003

BACKGROUND: Warfarin is an anticoagulant indicated for patients who had undergone mechanical heart valve(s) replacement (MHVR). In these patients, time in therapeutic range (TTR) is important in predicting the bleeding and thrombotic risks.
OBJECTIVE: This study aimed to describe the anticoagulation control of warfarin using TTR in patients with MHVR in a tertiary health care referral Center.
METHODS: Data were collected retrospectively by reviewing clinical notes of outpatients who attended international normalized ratio (INR) clinics in November 2015. Patients who had MHVR and who took warfarin were included. The data collected were demographics, relevant laboratory investigations, and patients' prior medical history. TTR was calculated using Rosendaal and traditional methods.
RESULTS: A total of 103 patients with MHVR were recruited. The mean age was 51.72 ± 13.97 years and 46.6% were male. A total of 54.4% had mitral valve replacement (MVR), whereas 26.2% had aortic valve replacement (AVR). The mean TTR calculated using the Rosendaal method was 57.1%. There was no significant difference among patients with AVR, MVR, and both valves (AMVR) in terms of TTR (AVR vs. MVR vs. AMVR, 62.94 ± 23.08, 54.12 ± 21.62, 57.63 ± 17.47; p = 0.213). The average dose of warfarin for all groups was approximately 3 mg/day. Moreover, MVR, AVR, and AMVR patients who had TTR (Rosendaal method) ≤60% were 58.9%, 37.0%, and 45.0%, respectively. Only 4.8% had minor bleeding, whereas none had stroke in the period of TTR determination.
CONCLUSIONS: Despite a majority of patients having <60% TTR, there were low incidences of bleeding and stroke events in this center. There were no factors found to be associated with INR control in this study.
Study site: INR clinic, Sarawak Heart Centre, Sarawak General Hospital, Malaysia
Fulltext Supramolecular Nested Microbeads as Building Blocks for Macroscopic Self-Healing Scaffolds

Yu Z, Liu J, Tan CSY, Scherman OA, Abell C

Angew Chem Int Ed Engl, 2018 03 12;57(12):3079-3083.
PMID: 29377541 DOI: 10.1002/anie.201711522

The ability to construct self-healing scaffolds that are injectable and capable of forming a designed morphology offers the possibility to engineer sustainable materials. Herein, we introduce supramolecular nested microbeads that can be used as building blocks to construct macroscopic self-healing scaffolds. The core-shell microbeads remain in an "inert" state owing to the isolation of a pair of complementary polymers in a form that can be stored as an aqueous suspension. An annealing process after injection effectively induces the re-construction of the microbead units, leading to supramolecular gelation in a preconfigured shape. The resulting macroscopic scaffold is dynamically stable, displaying self-recovery in a self-healing electronic conductor. This strategy of using the supramolecular assembled nested microbeads as building blocks represents an alternative to injectable hydrogel systems, and shows promise in the field of structural biomaterials and flexible electronics.
Tough Supramolecular Polymer Networks with Extreme Stretchability and Fast Room-Temperature Self-Healing

Liu J, Tan CSY, Yu Z, Li N, Abell C, Scherman OA

Adv Mater, 2017 Jun;29(22).
PMID: 28370560 DOI: 10.1002/adma.201605325

Recent progress on highly tough and stretchable polymer networks has highlighted the potential of wearable electronic devices and structural biomaterials such as cartilage. For some given applications, a combination of desirable mechanical properties including stiffness, strength, toughness, damping, fatigue resistance, and self-healing ability is required. However, integrating such a rigorous set of requirements imposes substantial complexity and difficulty in the design and fabrication of these polymer networks, and has rarely been realized. Here, we describe the construction of supramolecular polymer networks through an in situ copolymerization of acrylamide and functional monomers, which are dynamically complexed with the host molecule cucurbit[8]uril (CB[8]). High molecular weight, thus sufficient chain entanglement, combined with a small-amount dynamic CB[8]-mediated non-covalent crosslinking (2.5 mol%), yields extremely stretchable and tough supramolecular polymer networks, exhibiting remarkable self-healing capability at room temperature. These supramolecular polymer networks can be stretched more than 100× their original length and are able to lift objects 2000× their weight. The reversible association/dissociation of the host-guest complexes bestows the networks with remarkable energy dissipation capability, but also facile complete self-healing at room temperature. In addition to their outstanding mechanical properties, the networks are ionically conductive and transparent. The CB[8]-based supramolecular networks are synthetically accessible in large scale and exhibit outstanding mechanical properties. They could readily lead to the promising use as wearable and self-healable electronic devices, sensors and structural biomaterials.
Fulltext Eco-friendly cellulose hydrogels as controlled release fertilizer for enhanced growth and yield of upland rice

Abg Ahmad DFB, Wasli ME, Tan CSY, Musa Z, Chin SF

Sci Rep, 2023 Nov 22;13(1):20453.
PMID: 37993538 DOI: 10.1038/s41598-023-47922-y

The effect of urea-loaded cellulose hydrogel, a controlled-release fertilizer (CRF) on growth and yield of upland rice were investigated in upland rice. As with the initial research, nitrogen (N) treatments were applied as CRF treatments; T2H (30 kg N ha-1), T3H (60 kg N ha-1), T4H (90 kg N ha-1), T5H (120 kg N ha-1) and recommended dose of fertilizer (RDF) at 120 kg N ha-1 RDF (T6U) in split application and T1 (0 N) as control. Results from this study indicated that applying CRF at the optimum N rate, T4H resulted in maximum grain yield, increasing by 71%. The analysis of yield components revealed that higher grain yield in T4H CRF was associated with an increase in panicle number and number of grains per panicle. Maximum grain N uptake of 0.25 g kg-1 was also observed in T4H CRF. In addition, T4H CRF recorded the highest harvest index (HI) and N harvest index (NHI) of 45.5% and 67.9%, respectively. Application of T4H CRF also recorded the highest N use efficiency (NUE) and N agronomic efficiency (NAE), 52.6% and 12.8 kg kg-1, respectively. Observations show that CRF with only 75% N applied (T4H) in soil improved grain yield when compared to CRF with 100% N and 100% RDF in farmers' conventional split application. This suggested that CRF with a moderate N application might produce the highest potential yield and improved N efficiencies while enhancing crop production and further increase in N supply did not increase yield and N efficiencies. The results suggest that the application of T4H CRF for upland rice would enhance HI, N efficiencies and improve the yield of upland rice. Also, all growth parameters and yield were positively influenced by the application of CRF as a basal dose compared to split application of conventional urea fertilizers.
Fulltext Sociocultural factors affecting drive for muscularity among male college students in Malaysia

Sai A, Furusawa T, Othman MY, Tomojiri D, Wan Zaini WFZ, Tan CSY, et al.

Heliyon, 2020 Jul;6(7):e04414.
PMID: 32743089 DOI: 10.1016/j.heliyon.2020.e04414

Compared with females, little research on muscularity and the sociocultural influences on this domain has been conducted with males in non-Western societies. The current study explored these sociocultural predictors of drive for muscularity among Malaysian male college students, specifically in terms of ethnicity and exposure to media (i.e., Internet and social media). In total, 166 male college students from two universities in Kuala Lumpur were asked to rate the questionnaires as to muscularity-oriented attitudes and behaviours. Multivariable general linear model analyses revealed that being Chinese was a strong predictor of muscularity-oriented attitudes and behaviours. In addition, modern media, particularly, Internet use and the number of followers on Instagram, was found to significantly predict males' drive for muscularity. Overall findings suggest that males of particular ethnic groups may be at higher risk for negative body image compared to the other ethnic populations and modern media use may accelerate drive for muscularity, which may also in turn place males at higher risk for excess muscularity-oriented thoughts and behaviours.
Fulltext Improving bedside dispensing services through early medication discharge planning: a pre-post intervention study

Oh AL, Tan YJ, Chong WC, Chieng IYY, Chan JYM, Kho BP, et al.

J Pharm Policy Pract, 2022 Jan 24;15(1):7.
PMID: 35073999 DOI: 10.1186/s40545-022-00405-3

BACKGROUND: Delays in producing discharge prescriptions have hindered the provision of bedside dispensing services (BEDISC) that enable medication reconciliation and pharmaceutical intervention, which is an important element in transitional care medication safety. We aimed to assess the impact of early medication discharge planning on the delivery of BEDISC in terms of the rate of bedside dispensing, medication errors, and cost-saving from medication reconciliation by reusing patient's own medicines (POMs).
METHODS: A pre-post intervention study was conducted at medical wards in a public tertiary hospital. During the intervention phase, a structured bedside dispensing process was delineated and conveyed to the doctors, nurses, and pharmacists. Regular verbal reminders were given to the doctors to prioritize discharge patients by producing the prescriptions once discharge decisions had been made and nurses to hand the prescriptions to ward pharmacists and not patients. Throughout the study, ward pharmacists were involved in medication reconciliation via screening of discharge prescriptions and reusing POMs, performed pharmaceutical interventions for any medication errors detected, and provided bedside dispensing with discharge counseling. Comparisons were made between bedside versus counter-dispensing at pre-post intervention phases using the chi-square test.
RESULTS: A total of 1097 and 817 discharge prescriptions were dispensed in the pre-intervention and post-intervention phases, respectively. The bedside dispensing rate increased by 13.5% following remedial actions (p
Fulltext Emerging Two-Dimensional Crystallization of Cucurbit[8]uril Complexes: From Supramolecular Polymers to Nanofibers

Barrio JD, Liu J, Brady RA, Tan CSY, Chiodini S, Ricci M, et al.

J Am Chem Soc, 2019 09 11;141(36):14021-14025.
PMID: 31422657 DOI: 10.1021/jacs.9b07506

The binding of imidazolium salts to cucurbit[8]uril, CB[8], triggers a stepwise self-assembly process with semiflexible polymer chains and crystalline nanostructures as early- and late-stage species, respectively. In such a process, which involves the crystallization of the host-guest complexes, the guest plays a critical role in directing self-assembly toward desirable morphologies. These include platelet-like aggregates and two-dimensional (2D) fibers, which, moreover, exhibit viscoelastic and lyotropic properties. Our observations provide a deeper understanding of the self-assembly of CB[8] complexes, with fundamental implications in the design of functional 2D systems and crystalline materials.
Current recycling strategies and high-value utilization of waste cotton

Lu L, Fan W, Meng X, Xue L, Ge S, Wang C, et al.

Sci Total Environ, 2023 Jan 15;856(Pt 1):158798.
PMID: 36116663 DOI: 10.1016/j.scitotenv.2022.158798

The rapid development of the textile industry and improvement of people's living standards have led to the production of cotton textile and simultaneously increased the production of textile wastes. Cotton is one of the most common textile materials, and the waste cotton accounts for 24% of the total textile waste. To effectively manage the waste, recycling and reusing waste cotton are common practices to reduce global waste production. This paper summarizes the characteristics of waste cotton and high-value products derived from waste cotton (e.g., yarns, composite reinforcements, regenerated cellulose fibers, cellulose nanocrystals, adsorptive materials, flexible electronic devices, and biofuels) via mechanical, chemical, and biological recycling methods. The advantages and disadvantages of making high-value products from waste cotton are summarized and discussed. New technologies and products for recycling waste cotton are proposed, providing a guideline and direction for merchants and researchers. This review paper can shed light on converting textile wastes other than cotton (e.g., bast, silk, wool, and synthetic fibers) into value-added products.