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Currently, most customized hydrogels can only be processed via extrusionbased 3D printing techniques, which is limited by printing efficiency and resolution. Here, a simple strategy for the rapid fabrication of customized hydrogels using a photocurable 3D printing technique is presented. This technique has been rarely used because the presence of water increases the molecular distance between the polymer chains and reduces the monomer polymerization rate, resulting in the failure of rapid solid-liquid separation during printing. Although adding cross-linkers to printing inks can effectively accelerate 3D cross-linked network formation, chemical cross-linking may result in reduced toughness and self-healing ability of the hydrogel. Therefore, an interpenetrated-network hydrogel based on non-covalent interactions is designed to form physical cross-links, affording fast solid-liquid separation. Poly(acrylic acid (AA)-N-vinyl-2-pyrrolidone (NVP)) and carboxymethyl cellulose (CMC) are cross-linked via Zn 2+ -ligand coordination and hydrogen bonding; the resulting mixed AA-NVP/CMC solution is used as the printing ink. The printed poly(AA-NVP/CMC) hydrogel exhibited high tensile toughness (3.38 MJ m −3 ) and superior self-healing ability (healed stress: 81%; healed strain: 91%). Some objects like manipulator are successfully customized by photocurable 3D printing using hydrogels with high toughness and complex structures. This high-performance hydrogel has great potential for application in flexible wearable sensors.

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Cardiovascular disease constitutes the primary cause of mortality and morbidity worldwide, and represents a group of disorders associated with the loss of cardiac function. Despite considerable advances in the understanding of the pathologic mechanisms of the disease, the majority of the currently available therapies remain at best palliative, since the problem of cardiac tissue loss has not yet been addressed. Indeed, few therapeutic approaches offer direct tissue repair and regeneration, whereas the majority of treatment options aim to limit scar formation and adverse remodeling, while improving myocardial function. Of all the existing therapeutic approaches, the problem of cardiac tissue loss is addressed uniquely by heart transplantation. Nevertheless, alternative options, particularly stem cell therapy, has emerged as a novel and promising approach. This approach involves the transplantation of healthy and functional cells to promote the renewal of damaged cells and repair injured tissue. Bone marrow precursor cells were the first cell type used in clinical studies, and subsequently, preclinical and clinical investigations have been extended to the use of various populations of stem cells. This review addresses the present state of research as regards stem cell therapy for cardiovascular disease.

Thermoplastic polyurethane (TPU) elastomers are widely used in daily products owing to their flexible structures and decent mechanical properties. Vegetable oils (VOs) are promising renewable resources for polymer synthesis with readily availability and abundant derivatives. However, most VO-based polyurethanes are usually thermosets with an unsatisfactory material performance because the CC bonds are randomly located on triglyceride long chains. Herein, a biobased TPU elastomer was facilely synthesized from palm oil (PO) with desirable and tunable mechanical properties. PO-based diol was synthesized from PO via amidation with 2-(2-hydroxyethylamino)­ethanol. The resulting PO diethanolamide (POEA), combined with biobased butane-1,4-diol, was further reacted with 1,6-diisocyanatohexane to prepare PO-based TPU elastomers. The elastomers containing abundant H-bonds from carbamates in the backbone and dangling fatty acid side chains exhibited a microphase separation structure, endowing the elastomers with superior stretchability (up to a strain of 831%), restorability, and self-healing ability. The morphological, melting, crystallization, and rheological behaviors of the elastomers were fully studied. The dynamic and reversible three-dimensional cross-linked network consisting of van der Waals forces and H-bonds was investigated to reveal the formation mechanism of the elastomers.

Fabrication of reliable large-sized p-ZnO is a major challenge to realise ZnO-based electronic device applications. Here we report a novel technique to grow high-quality free-standing undoped acceptor-rich ZnO (A-ZnO) microtubes with dimensions of ~100 μm (in diameter) × 5 mm (in length) by optical vapour supersaturated precipitation. The A-ZnO exhibits long lifetimes (>1 year) against compensation/lattice-relaxation and the stable shallow acceptors with binding energy of ~127 meV are confirmed from Zn vacancies. The A-ZnO provides a possibility for a mimetic p-n homojunction diode with n+-ZnO:Sn. The high concentrations of holes in A-ZnO and electrons in n+-ZnO make the dual diffusion possible to form a depletion layer. The diode threshold voltage, turn-on voltage, reverse saturated current and reverse breakdown voltage are 0.72 V, 1.90 V, <10 μA and >15 V, respectively. The A-ZnO also demonstrates quenching-free donor-acceptor-pairs (DAP) emission located in 390–414 nm with temperature of 270–470 K. Combining the temperature-dependent DAP violet emission with native green emission, the visible luminescence of A-ZnO microtube can be modulated in a wide region of colour space across white light. The present work opens up new opportunities to achieve ZnO with rich and stable acceptors instead of p-ZnO for a variety of potential applications.

Background The coronavirus disease 2019 (COVID-19) first emerged in Wuhan, China, and soon caused an ongoing pandemic globally. In this study we conducted a retrospective study to evaluate the safety and efficacy of combined spinal-epidural anaesthesia (CSEA) and infection control measures on perinatal care quality of 30 pregnant women with confirmed and suspected COVID-19. Methods Individual demographic data, clinical outcomes, laboratory investigations of pregnant women and their newborns were collected from electronic medical records of the Maternal and Children Health Hospital of Hubei Province, during January 24 to February 29, 2020. Anaesthesia and surgery results were compared between pregnant women with confirmed and suspected COVID-19 infection. Results Using CSEA in cesarean section was effective and safe for pregnant women with confirmed and suspected COVID-19 infection. Administration of dezocine and morphine was effective as postoperative analgesia, and well tolerated in COVID-19 patients. The assessment of surgery outcomes also showed similar results in both confirmed and suspected cases. No respiratory failure nor distress were found in the mothers with confirmed COVID-19 infection and their neonates. None of these patients experienced severe obstetric complications related to anaesthesia and surgeries. No COVID-19 infection was reported in the neonates born to the mothers with confirmed COVID-19 infection and healthcare workers in these operations. Conclusions In cesarean section for pregnant women with COVID-19 infection, CSEA was safe and efficient in achieving satisfactory obstetrical anaesthesia and postoperative analgesia. No cross-infection occurred in the HCWs working in these operations.