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1.
Int J Biol Macromol ; 260(Pt 1): 129372, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38237818

RESUMO

Recently, photothermal nanomaterials has attracted enormous interests owing to their enhanced therapeutic effects and less adverse effects in the treatment of infectious diseases. Herein, this work presents a photothermally responsive antimicrobial, bioadhesive hydrogel through three dimensions (3D) printing technology for treatment the wound infection. The hydrogel is based on a visible-light-activated naturally derived polymer (GelMA), GelMA grafted with dopamine (GelMA-DA) and the polydopamine coated reduced graphene oxide (rGO@PDA), which can provide the multifunctional such as photothermal antibacterial, antioxidant, conductivity, adhesion and hemostasis performance to accelerate wound healing. The developed hydrogel shown the excellent adhesion capability to adhere the in vitro physiological tissues and glass surface. Moreover, the fabricated hydrogel also exhibited excellent cytocompatibility to L929 cells which is a vital biofunction for efficiently promoting cell proliferation and migration in vitro. The hydrogel also showed remarkable photothermally responsive antimicrobial capability against two strains (99.3 % antibacterial ratio for E. coli and 98.6 % antibacterial ratio for S. aureus). Furthermore, it could support the wound repair and regeneration of S. aureus infected full-thickness wound defects in rats. Overall, the 3D printed hydrogel could be used as a photothermal platform for the development of more effective therapies against the infected wound.


Assuntos
Anti-Infecciosos , Metacrilatos , Infecção dos Ferimentos , Animais , Ratos , Hidrogéis/farmacologia , Escherichia coli , Staphylococcus aureus , Infecção dos Ferimentos/tratamento farmacológico , Antibacterianos/farmacologia , Impressão Tridimensional , Gelatina
2.
Eur J Dent Educ ; 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38148502

RESUMO

INTRODUCTION: Virtual reality (VR) and haptic simulation technology have been increasingly implemented in dental training. Since the first haptic VR dental simulator (Simodont) was introduced 10 years ago, it has been applied in more than 40 universities in mainland China. This scoping review aimed to review literature, showcasing the teaching reform of dental virtual simulation in mainland China to global dental education peers. METHODS: This scoping review was conducted using the PRISMA extension for scoping review guidelines. Seven electronic databases were searched, and two reviewers independently performed the selection and characterization of the studies. RESULTS: The final scoping review included 12 studies. Four studies focused on the G. V. Black class II cavity, three on manual dexterity skills training, two on full metal crown preparation, one on pulpal access and coronal cavity preparation, one on flipped classroom teaching, and one on 'doctor-patient communication' skills. DISCUSSION: The most critical scenarios, self-assessment, working posture, curriculum setting, training and cost are analysed and discussed. CONCLUSION: Haptic simulation technology is a valuable complementary tool to the phantom head in dental education. The combined utilization of these two training devices has been superior to either in isolation. However, there is a lack of research on the sequencing of the two systems, as well as the appropriate distribution of curriculum between them. It is necessary for educators to organize or engage in experience sharing, collaboration and knowledge dissemination. These actions are essential for promoting effective teaching within dental educational institutions.

3.
Polymers (Basel) ; 14(21)2022 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-36365749

RESUMO

Bacterial cellulose (BC) has become a universal biomaterial owing to its intrinsic properties. BC fibers are composed of microfibers with a diameter of 3-4 nm into fiber bundles with a thickness of 40-60 nm, and interweave with each other to form a well-developed ultra-fine network structure. Polylactic acid (PLA) has good mechanical properties and excellent biocompatibility and biodegradability. Therefore, PLA has been widely applied in tissue engineering. Addressed herein is a novel type of PLA/BC (PLA/BC) composite scaffold prepared by 3D printing (3D), 3D modeling of the required porous membrane material support established in the computer, and decomposition of the model into 5 layer 20 µM sheets. The range of PLA loadings assessed in this work was 1.0 wt.%, 1.5 wt.%, and 2.0 wt.%, and its physicochemical properties and biological properties were characterized and evaluated. Tensile strength of PLA/BC composite scaffolds increased to 66.49 MPa compared to that of a pure BC film (25.61 MPa). Hydrophilicity was tunable with the amount of added PLA. In this paper, the effects of 3D round hole and stripe surface topology on cell growth behavior were characterized. Schwann cells (SCs) adhered to the surface of the 3D composite membrane successfully, and their proliferation rate on the surface of the regular circular pore and stripe structure was better than that of the smooth surface. Erythrocyte fixation and platelet adhesion experiments showed that the 3D composite scaffold had excellent blood compatibility. Further degradation studies showed that loose structures appeared after 1 week, and structural defects began after 3 weeks. The in vitro degradation results showed that the degradation rate of the BC membrane in simulated body fluid after 6 weeks was 14.38%, while the degradation rate of the PLA/BC composite scaffold was 18.75%.

4.
J Chem Theory Comput ; 18(12): 7073-7081, 2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36350795

RESUMO

The photoinduced ring-opening reaction of 1,3-cyclohexadiene to produce 1,3,5-hexatriene is a classic electrocyclic reaction and is also a prototype for many reactions of biological and synthetic importance. Here, we simulate the ultrafast nonadiabatic dynamics of the reaction in the manifold of the three lowest valence electronic states by using extended multistate complete-active-space second-order perturbation theory (XMS-CASPT2) combined with the curvature-driven coherent switching with decay of mixing (κCSDM) dynamical method. We obtain an excited-state lifetime of 79 fs, and a product quantum yield of 40% from the 500 trajectories initiated in the S1 excited state. The obtained lifetime and quantum yield values are very close to previously reported experimental and computed values, showing the capability of performing a reasonable nonadiabatic ring-opening dynamics with the κCSDM method that does not require nonadiabatic coupling vectors, time derivatives, or diabatization. In addition, we study the ring-opening reaction by initiating the trajectories in the dark state S2. We also optimize the S0/S1 and S1/S2 minimum-energy conical intersections (MECIs) by XMS-CASPT2; for S1/S2, we optimized both an inner and an outer local-minimum-energy conical intersections (LMECIs). We provide the potential energy profile along the ring-opening coordinate by joining selected critical points via linear synchronous transit paths. We find the inner S1/S2 LMECI to be more crucial than the outer one.

5.
Nanomaterials (Basel) ; 12(18)2022 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-36144913

RESUMO

Polymer doping is an efficient approach to achieve self-healing perovskite solar cells. However, achieving high self-healing efficiency under moderate conditions remains challenging. Herein, an innovative self-healable polysiloxane (PAT) containing plenty of thiourea hydrogen bonds was designed and introduced into perovskite films. Abundant thiourea hydrogen bonds in PAT facilitated the self-healing of cracks at grain boundaries for damaged SPSCs. Importantly, the doped SPSCs demonstrated a champion efficiency of 19.58% with little hysteresis, almost rivalling those achieved in control atmosphere. Additionally, owing to the effective chelation by PAT and good level of thiourea hydrogen bonds, after 800 cycles of stretching, releasing and self-healing, the doped SPSCs retained 85% of their original IPCE. The self-healing characteristics were demonstrated in situ after stretching at 20% strain for 200 cycles. This strategy of pyridine-based supramolecular doping in SPSCs paves a promising way for achieving efficient and self-healable crystalline semiconductors.

6.
Chemosphere ; 307(Pt 1): 135780, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35870608

RESUMO

Thermosetting unsaturated polyester resin (UPR) composites were found widespread industrial applications. However, the numerous stable carbon-carbon bonds in cross-linked networks made them intractable for degradation, causing the large-scale composite wastes. Here a nanoscale Fe0 catalyst in-situ forming strategy was exploited to nondestructively recycle carbon fiber (CF) from UPR composites via Fenton-like reaction. The nano-Fe0 catalyst employed in this strategy activated H2O2 for removing UPR, featuring mild conditions and efficient degradation ability. Aiming at facile growth of the catalyst, a porous UPR was achieved by the hydrolysis of alkalic system. The nanoscale Fe0 catalyst was subsequently formed in-situ on the surface of hydrolyzed resin by borohydride reduction. Benefiting from fast mass transfer, the in-situ grown nano-Fe0 showed more efficient degradation ability than added nano-Fe0 or Fe2+ catalyst during Fenton-like reaction. The experiments indicated that hydrolyzed resin could be degraded more than 90% within 80 min, 80 °C. GC-MS, FT-IR analysis and Density functional theory (DFT) calculation were conducted to explained the fracture processes of carbon skeleton in hydrolyzed resin. Especially, a remarkable recovery process of CF from composites was observed, with a 100 percent elimination of resin. The recycled CF cloth exhibited a 99% strength retention and maintained the textile structure, microtopography, chemical structure, resulting in the nondestructive reclaim of CF. This in-situ formed nanoscale Fe0 catalytic degradation strategy may provide a promising practical application for nondestructively recycle CF from UPR composites.


Assuntos
Peróxido de Hidrogênio , Ferro , Boroidretos , Carbono , Fibra de Carbono , Catálise , Peróxido de Hidrogênio/química , Ferro/química , Poliésteres , Espectroscopia de Infravermelho com Transformada de Fourier
7.
J Chem Theory Comput ; 18(6): 3523-3537, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35580263

RESUMO

The many-body GW approximation, especially the G0W0 method, has been widely used for condensed matter and molecules to calculate quasiparticle energies for ionization, electron attachment, and band gaps. Because G0W0 calculations are well-known to have a strong dependence on the orbitals, the goal of the present work is to provide guidance on the choice of density functional used to generate orbitals and to recommend a choice that gives the most broadly accurate results. We have systematically investigated the dependence of G0W0 calculations on the orbitals for 100 molecules and 8 crystals by considering orbitals obtained with a diverse set of Kohn-Sham (KS) and generalized KS (GKS) functionals (63 functionals plus Hartree-Fock). The percentage of Hartree-Fock exchange employed in density functionals has been found to have strong influence on the predicted molecular ionization energy and crystal fundamental band gaps (with optimum values between 40 and 56%), but to have less effect on predicting molecular electron affinities. The low cost of the Gaussian implementation, even with hybrid functionals in periodic calculations, the better performance of global hybrids as compared to range-separated hybrids of either than screened exchange or long-range-corrected type, and the relatively low cost of global-hybrid-functional periodic calculations using Gaussians means that one can employ global-hybrid functionals at a very reasonable cost and obtain more accurate band gaps of semiconductors than are obtained by the methods currently widely employed, namely local gradient approximations. We single out three global-hybrid functionals that give especially good results for both molecules (100 in the test set) and crystals (8 in the test set, for all of which our benchmark data are the proper band gap rather than an optical band gap uncorrected for exciton effects).

8.
Transl Androl Urol ; 11(3): 293-303, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35402196

RESUMO

Background: Investigate the effects of Stellera chamaejasme on microvascular density and apoptosis of cancer cells in rat bladder tumor models. Methods: The bladder tumor model of 75 specific pathogen-free (SPF)-grade Sprague-Dawley (SD) rats aged 5-6 weeks was established by n-methyl-N-nitrosourea (MNU) bladder perfusion induction, and the model rats were randomly divided into model group, low-dose (L-dose) group, medium-dose (M-dose) group, high-dose (H-dose) group, and positive drug (hydroxycamptothecine, HCPT) group. L-dose group, M-dose group, and H-dose group were treated with 5 g/kg, 10 g/kg, and 20 g/kg, respectively. The HCPT group was treated with 2 mg/kg hydroxycamptothecin at 1 mL/kg once a week and the model group were treated with the same amount of normal saline for 4 weeks. The quality of bladder cancer tissues in each group was measured. The pathological changes and microvascular density of bladder tissues were observed, and the apoptosis rate of vascular endothelial growth factor (VEGF), tumor tissue and the protein expression levels of factor associated suicide (Fas), factor associated suicide ligand (FasL) and Caspase3 in bladder tissues were detected. Results: Bladder cancer was induced 14 weeks after initial bladder perfusion with MNU. In the model group, epithelial cells of bladder tissue showed atypically hyperplasia with various sizes and disorders. After treatment with Stellera chamaejasme, the hematoxylin-eosin (HE) scores, bladder weight, microvascular density, and VEGF were significantly decreased, and the tumor inhibition rate, cell apoptosis, and the expression of apoptosis-related proteins Fas, FasL, and Caspase3 were significantly increased in the bladder tissue. The above changes were dose-dependent with Stellera chamaejasme. Conclusions: MNU can be used to prepare a rat bladder cancer model. Stellera chamaejasme has a good therapeutic effect on rat bladder cancer, which may inhibit the progression of bladder cancer by inhibiting micro-angiogenesis and inducing the apoptosis of bladder tumor cells.

9.
Mater Horiz ; 9(5): 1495-1502, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35315458

RESUMO

The γ ray is a promising candidate for thermoset material degradation owing to its high energy, strong penetrability, low carbon emission and economy. However, the development of irradiation degradation technology is limited by irradiation cross-linking and irradiation degradation simultaneously, and a controllable degradation remains a considerable challenge. Herein, we exploit stable conjugated linkages, phenyl imine conjugated N-N bonds, for the γ-ray-induced controllable cleavage of polymer chains. Using this distinctive conjugated structure, we design γ-ray-responsive epoxy networks that can be readily degraded at a dose of 40 kGy at room temperature and show mechanical properties, thermal properties and chemical resistance comparable to commodity epoxy resins. Additionally, the incorporation of a radical scavenger can reduce the uncontrolled recombination of degradation segments, which further accelerates the degradation of the epoxy thermosets.

10.
J Chem Theory Comput ; 18(3): 1320-1328, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35104136

RESUMO

Direct dynamics by mixed quantum-classical nonadiabatic methods is an important tool for understanding processes involving multiple electronic states. Very often, the computational bottleneck of such direct simulation comes from electronic structure theory. For example, at every time step of a trajectory, nonadiabatic dynamics requires potential energy surfaces, their gradients, and the matrix elements coupling the surfaces. The need for the couplings can be alleviated by employing the time derivatives of the wave functions, which can be evaluated from overlaps of electronic wave functions at successive time steps. However, evaluation of overlap integrals is still expensive for large systems. In addition, for electronic structure methods for which the wave functions or the coupling matrix elements are not available, nonadiabatic dynamics algorithms become inapplicable. In this work, building on recent work by Baeck and An, we propose new nonadiabatic dynamics algorithms that only require adiabatic potential energies and their gradients. The new methods are named curvature-driven coherent switching with decay of mixing (κCSDM) and curvature-driven trajectory surface hopping (κTSH). We show how powerful these new methods are in terms of computation time and accuracy as compared to previous mixed quantum-classical nonadiabatic dynamics algorithms. The lowering of the computational cost will allow longer nonadiabatic trajectories and greater ensemble averaging to be affordable, and the ability to calculate the dynamics without electronic structure coupling matrix elements extends the dynamics capability to new classes of electronic structure methods.

11.
Angew Chem Int Ed Engl ; 61(18): e202116955, 2022 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-35191583

RESUMO

Although heptagons are widely found in graphenic materials, the precise synthesis of nanocarbons containing heptagons remains a challenge, especially for the nanocarbons containing multiple-heptagons. Herein, we show that photo-induced radical cyclization (PIRC) can be used to synthesize multi-heptagon-embedded nanocarbons. Notably, a nanographene containing six heptagons (1) was obtained via a six-fold cascade PIRC reaction. The structure of 1 was clearly validated and showed a Monkey-saddle-shaped conformation. Experimental bond analysis and theoretical calculations indicated that the heptagons in 1 were non-aromatic, whereas the peripheral rings were highly aromatic. Compared to planar nanographene with the same number of π electrons, 1 had a similar optical gap due to a compromise between the decreased conjugation in the wrapped structure and enhanced electronic delocalization at the rim. Electrochemical studies showed that 1 had low-lying oxidation potentials, which was attributed to the nitrogen-doping.

12.
Nat Commun ; 13(1): 278, 2022 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-35022406

RESUMO

Lithium-sulfur (Li-S) batteries have a high specific capacity, but lithium polysulfide (LPS) diffusion and lithium dendrite growth drastically reduce their cycle life. High discharge rates also necessitate their resilience to high temperature. Here we show that biomimetic self-assembled membranes from aramid nanofibers (ANFs) address these challenges. Replicating the fibrous structure of cartilage, multifactorial engineering of ion-selective mechanical, and thermal properties becomes possible. LPS adsorption on ANF surface creates a layer of negative charge on nanoscale pores blocking LPS transport. The batteries using cartilage-like bioinspired ANF membranes exhibited a close-to-theoretical-maximum capacity of 1268 mAh g-1, up to 3500+ cycle life, and up to 3C discharge rates. Essential for safety, the high thermal resilience of ANFs enables operation at temperatures up to 80 °C. The simplicity of synthesis and recyclability of ANFs open the door for engineering high-performance materials for numerous energy technologies.

13.
Angew Chem Int Ed Engl ; 61(4): e202112673, 2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-34787353

RESUMO

Polymer doping is a significant approach to precisely control nucleation and crystal growth of perovskites and enhance electronic quality in perovskite solar cells (PSC) prepared in air. Here, a brand-new self-healing polysiloxane (SHP) with dynamic 2,6-pyridinedicarboxamide (PDCA) coordination units and plenty of hydrogen bonds was designed and incorporated into perovskite films. PDCA units, showing strong intermolecular Pb2+ -Namido , I- -Npyridyl , and Pb2+ -Oamido coordination interactions, were expected to enhance crystallinity and passivate the grain boundary. In addition, abundant hydrogen bonds in SHP afforded the self-healing of cracks at grain boundaries for fatigue PSCs. Significantly, the doped device demonstrated a champion efficiency of 19.50 % with inconspicuous hysteresis, almost rivaling those achieved in control atmosphere. This strategy of heterocyclic-based macromolecular doping in PSCs will pave a way for realizing efficient and durable crystalline semiconductors.

14.
Polymers (Basel) ; 13(23)2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34883724

RESUMO

Injectable hydrogels, which are formed in situ by changing the external stimuli, have the unique characteristics of easy handling and minimal invasiveness, thus providing the advantage of bypass surgical operation and improving patient compliance. Using external temperature stimuli to realize the sol-to-gel transition when preparing injectable hydrogel is essential since the temperature is stable in vivo and controllable during ex vivo, although the hydrogels obtained possibly have low mechanical strength and stability. In this work, we designed an in situ fast-forming injectable cellulose/albumin-based hydrogel (HPC-g-AA/BSA hydrogels) that responded to body temperature and which was a well-stabilized hydrogen-bonding network, effectively solving the problem of poor mechanical properties. The application of localized delivery of chemotherapeutic drugs of HPC-g-AA/BSA hydrogels was evaluated. In vitro and in vivo results show that HPC-g-AA/BSA hydrogels exhibited higher antitumor efficacy of reducing tumor size and seem ideal for localized antitumor therapy.

15.
Membranes (Basel) ; 11(12)2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34940433

RESUMO

Membrane fouling has been one of the most important challenges in membrane separation operations. In this study, we report a facile strategy to prepare antifouling polysulfone (PSf) UF membranes by blending amphiphilic zwitterion polysulfone-co-sulfobetaine polysulfone (PSf-co-SBPSf) copolymer. The copolymer chemical structure was characterized by 1HNMR spectroscopy. The PSf/PSf-co-SBPSf blend membranes with various zwitterionic SBPSf segment contents exhibited better surface hydrophilicity and excellent antifouling ability compared to PSf and PSf/PEG membranes. The significant increase of both porosity and water permeance indicates that the PSf-co-SBPSf has a pore-forming effect. The pure water flux and flux recovery ratio of the PSf/PSf-co-SBPSf blend membranes were both remarked to improve 286.43 L/m2h and 92.26%, while bovine serum albumin (BSA) rejection remained at a high level (97.66%). More importantly, the water flux and BSA rejection see minimal variance after heat treatment, indicating excellent thermostability. Overall, the PSf/PSf-co-SBPSf blend membranes achieved a comprehensive performance of sustainable hydrophilic, high permeation flux, and remarkable antifouling ability, thus becoming a promising candidate in high-temperature separation application.

16.
Nanomaterials (Basel) ; 11(11)2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34835715

RESUMO

Recently, biomass-based materials have attracted increasing attention because of their advantages of low cost, environment-friendly and nonpollution. Herein, the feasibility of using corn stalk biomass fiber (CF) and Fe3O4 embedded chitosan (CS) as a novel biomass-based adsorbent (CFS) to remove chloramphenicol (CAPC) from aqueous solution. Structure of CFS was characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and zeta potential techniques. The effects of solution pH, adsorption time and ion strength on the adsorption capacity were examined. Adsorption isotherms obtained from batch experiments were better fitted by Langmuir model compared with Freundlich model, Dubinin-Radushkevich model and Temkin model. Adsorption kinetic data matched well to the pseudo-second order kinetic model. CAPC adsorption was endothermic, spontaneous, and entropy-increasing nature on CFS. In addition, the CFS could be separated by an external magnetic field, recycled, and reused without any significant loss in the adsorption capacity of CAPC. Based on these excellent performances, there is potential that CFS can be considered as a proficient and economically suitable material for the CAPC removal from the water environment.

17.
R Soc Open Sci ; 8(10): 210121, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34754491

RESUMO

Dilute magnetic semiconductors (DMSs), such as (In, Mn)As and (Ga, Mn)As prototypes, are limited to III-V semiconductors with Curie temperatures (T c) far from room temperature, thereby hindering their wide application. Here, one kind of DMS based on perovskite niobates is reported. BaM x Nb(1-x)O3-δ (M = Fe, Co) powders are prepared by the composite-hydroxide-mediated method. The addition of M elements endows BaM x Nb(1-x)O3-δ with local ferromagnetism. The tetragonal BaCo x Nb(1-x)O3-δ nanocrystals can be obtained by Co doping, which shows strong saturation magnetization (M sat) of 2.22 emu g-1, a remnant magnetization (M r) of 0.084 emu g-1 and a small coercive field (H c) of 167.02 Oe at room temperature. The ab initio calculations indicate that Co doping could lead to a 64% local spin polarization at the Fermi level (E F) with net spin DOS of 0.89 electrons eV-1, this result shows the possibility of maintaining strong ferromagnetism at room temperature. In addition, the trade-off effect between the defect band absorption and ferromagnetic properties of BaM x Nb(1-x)O3-δ is verified experimentally and theoretically.

18.
ACS Sens ; 6(8): 2938-2951, 2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34328311

RESUMO

A biocompatible, flexible, yet robust conductive composite hydrogel (CCH) for wearable pressure/strain sensors has been achieved by an all-solution-based approach. The CCH is rationally constructed by in situ polymerization of aniline (An) monomers in the polyvinyl alcohol (PVA) matrix, followed by the cross-linking of PVA with glutaraldehyde (GA) as the cross-linker. The unique multiple synergetic networks in the CCH including strong chemical covalent bonds and abundance of weak physical cross-links, i.e., hydrogen bondings and electrostatic interactions, impart excellent mechanical strength (a fracture tensile strength of 1200 kPa), superior compressibility (ε = 80%@400 kPa), outstanding stretchability (a fracture strain of 670%), high sensitivity (0.62 kPa-1 at a pressure range of 0-1.0 kPa for pressure sensing and a gauge factor of 3.4 at a strain range of 0-300% for strain sensing, respectively), and prominent fatigue resistance (1500 cycling). As the flexible wearable sensor, the CCH is able to monitor different types of human motion and diagnostically distinguish speaking. As a proof of concept, a sensing device has been designed for the real-time detection of 2D distribution of weight or pressure, suggesting its promising potentials for electronic skin, human-machine interaction, and soft robot applications.


Assuntos
Hidrogéis , Dispositivos Eletrônicos Vestíveis , Condutividade Elétrica , Humanos , Monitorização Fisiológica , Álcool de Polivinil
19.
Nano Lett ; 21(11): 4700-4707, 2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34018750

RESUMO

Here, we report a novel topotactic method to grow 2D free-standing perovskite using KNbO3 (KN) as a model system. Perovskite KN with monoclinic phase, distorted by as large as ∼6 degrees compared with orthorhombic KN, is obtained from 2D KNbO2 after oxygen-assisted annealing at relatively low temperature (530 °C). Piezoresponse force microscopy (PFM) measurements confirm that the 2D KN sheets show strong spontaneous polarization (Ps) along [101̅]pc direction and a weak in-plane polarization, which is consistent with theoretical predictions. Thickness-dependent stripe domains, with increased surface displacement and PFM phase changes, are observed along the monoclinic tilt direction, indicating the preserved strain in KN induces the variation of nanoscale ferroelectric properties. 2D perovskite KN with low symmetry phase stable at room temperature will provide new opportunities in the exploration of nanoscale information storage devices and better understanding of ferroelectric/ferroelastic phenomena in 2D perovskite oxides.

20.
Mater Sci Eng C Mater Biol Appl ; 123: 111978, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33812606

RESUMO

Herein, we fabricated novel self-healing, in situ injectable, biodegradable, and non-toxic hydrogels anti-adhesion barrier materials composed of N, O-carboxymethyl chitosan (N,O-CS) and oxidized dextran (ODA) without requiring any chemical cross-linking agent or external stimuli triggers for the prevention and treatment of post-operative peritoneal adhesions. The N,O-CS/ODA hydrogels have a good suitable gelation time, good cytocompatibility and hemocompatibility, good antibacterial activity, excellent biodegradable and biocompatible, and can effectively inhibit the adhesion of fibroblasts to the wound, thereby suggesting that N,O-CS/ODA hydrogels are suitable for preventing post-operative adhesion. Meanwhile, a rat injury sidewall-cecum abrasion model is developed to investigate the efficacy of these hydrogels in achieving post-operative anti-adhesion. A significant reduction of peritoneal adhesions (10% rat with lower score adhesion) is observed in the N,O-CS/ODA-hydrogel-treated group compared with the commercial hydrogel and control groups. These results demonstrated that N,O-CS/ODA hydrogel could effectively prevent post-operative peritoneal adhesion without side effects. Therefore, the N,O-CS/ODA hydrogels with multi-functional properties exhibit great potential for the prevention and treatment of postoperative adhesion.


Assuntos
Quitosana , Hidrogéis , Adesivos , Animais , Antibacterianos/farmacologia , Bandagens , Quitosana/farmacologia , Hemostasia , Hidrogéis/farmacologia , Ratos , Ratos Sprague-Dawley
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