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1.
Adv Mater ; : e1905399, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31803996

RESUMO

The emulation of human sensation, perception, and action processes has become a major challenge for bioinspired intelligent robotics, interactive human-machine interfacing, and advanced prosthetics. Reflex actions, enabled through reflex arcs, are important for human and higher animals to respond to stimuli from environment without the brain processing and survive the risks of nature. An artificial reflex arc system that emulates the functions of the reflex arc simplifies the complex circuit design needed for "central-control-only" processes and becomes a basic electronic component in an intelligent soft robotics system. An artificial somatic reflex arc that enables the actuation of electrochemical actuators in response to the stimulation of tactile pressures is reported. Only if the detected pressure by the pressure sensor is above the stimulus threshold, the metal-organic-framework-based threshold controlling unit (TCU) can be activated and triggers the electrochemical actuators to complete the motion. Such responding mechanism mimics the all-or-none law in the human nervous system. As a proof of concept, the artificial somatic reflex arc is successfully integrated into a robot to mimic the infant grasp reflex. This work provides a unique and simplifying strategy for developing intelligent soft robotics, next-generation human-machine interfaces, and neuroprosthetics.

2.
Adv Mater ; : e1906156, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31693266

RESUMO

Oxygen vacancies play crucial roles in defining physical and chemical properties of materials to enhance the performances in electronics, solar cells, catalysis, sensors, and energy conversion and storage. Conventional approaches to incorporate oxygen defects mainly rely on reducing the oxygen partial pressure for the removal of product to change the equilibrium position. However, directly affecting reactants to shift the reaction toward generating oxygen vacancies is lacking and to fill this blank in synthetic methodology is very challenging. Here, a strategy is demonstrated to create oxygen vacancies through making the reaction energetically more favorable via applying interfacial strain on reactants by coating, using TiO2 (B) as a model system. Geometrical phase analysis and density functional theory simulations verify that the formation energy of oxygen vacancies is largely decreased under external strain. Benefiting from these, the obtained oxygen-deficient TiO2 (B) exhibits impressively high level of capacitive charge storage, e.g., ≈53% at 0.5 mV s-1 , far surpassing the ≈31% of the unmodified counterpart. Meanwhile, the modified electrode shows significantly enhanced rate capability delivering a capacity of 112 mAh g-1 at 20 C (≈6.7 A g-1 ), ≈30% higher than air-annealed TiO2 and comparable to vacuum-calcined TiO2 . This work heralds a new paradigm of mechanical manipulation of materials through interfacial control for rational defect engineering.

3.
Cell Biochem Funct ; 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31710116

RESUMO

Colorectal cancer (CRC) is a common human malignancy that accounts for 600,000 deaths annually worldwide. Chrysophanol, a naturally occurring anthraquinone compound, exhibits anti-neoplastic effects in various cancer cells. The aim of this study was to explore the biological effects of chrysophanol on CRC cells, and determine the underlying mechanism. Chrysophanol inhibited proliferation of and promoted apoptosis in CRC cells by activating the intrinsic mitochondrial apoptotic pathway. In addition, chrysophanol also suppressed tumor growth in vivo and increased the percentage of apoptotic cells in tumor xenografts, without general toxicity. Proteomic iTRAQ analysis revealed decorin (DCN) as the major target of chrysophanol. DCN was upregulated in the tumor tissues following chrysophanol treatment, and ectopic DCN expression markedly augmented the pro-apoptotic effects of chrysophanol in CRC cells. In contrast, DCN knockdown significantly abrogated chrysophanol-induced apoptosis in CRC cells. Taken together, chrysophanol exerts anti-neoplastic effects in vitro and in vivo in CRC cells by modulating DCN, there by highlighting its therapeutic potential in CRC.

4.
Nat Commun ; 10(1): 5384, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31772158

RESUMO

The emergence of wearable electronics puts batteries closer to the human skin, exacerbating the need for battery materials that are robust, highly ionically conductive, and stretchable. Herein, we introduce a supramolecular design as an effective strategy to overcome the canonical tradeoff between mechanical robustness and ionic conductivity in polymer electrolytes. The supramolecular lithium ion conductor utilizes orthogonally functional H-bonding domains and ion-conducting domains to create a polymer electrolyte with unprecedented toughness (29.3 MJ m-3) and high ionic conductivity (1.2 × 10-4 S cm-1 at 25 °C). Implementation of the supramolecular ion conductor as a binder material allows for the creation of stretchable lithium-ion battery electrodes with strain capability of over 900% via a conventional slurry process. The supramolecular nature of these battery components enables intimate bonding at the electrode-electrolyte interface. Combination of these stretchable components leads to a stretchable battery with a capacity of 1.1 mAh cm-2 that functions even when stretched to 70% strain. The method reported here of decoupling ionic conductivity from mechanical properties opens a promising route to create high-toughness ion transport materials for energy storage applications.

5.
J Neuroinflammation ; 16(1): 242, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31779652

RESUMO

BACKGROUND: Preserving the integrity of the blood-brain barrier (BBB) is beneficial to avoid further brain damage after acute ischemic stroke (AIS). Astrocytes, an important component of the BBB, promote BBB breakdown in subjects with AIS by secreting inflammatory factors. The glucagon-like peptide-1 receptor (GLP-1R) agonist exendin-4 (Ex-4) protects the BBB and reduces brain inflammation from cerebral ischemia, and GLP-1R is expressed on astrocytes. However, the effect of Ex-4 on astrocytes in subjects with AIS remains unclear. METHODS: In the present study, we investigated the effect of Ex-4 on astrocytes cultured under oxygen-glucose deprivation (OGD) plus reoxygenation conditions and determined whether the effect influences bEnd.3 cells. We used various methods, including permeability assays, western blotting, immunofluorescence staining, and gelatin zymography, in vitro and in vivo. RESULTS: Ex-4 reduced OGD-induced astrocyte-derived vascular endothelial growth factor (VEGF-A), matrix metalloproteinase-9 (MMP-9), chemokine monocyte chemoattractant protein-1 (MCP-1), and chemokine C-X-C motif ligand 1 (CXCL-1). The reduction in astrocyte-derived VEGF-A and MMP-9 was related to the increased expression of tight junction proteins (TJPs) in bEnd.3 cells. Ex-4 improved neurologic deficit scores, reduced the infarct area, and ameliorated BBB breakdown as well as decreased astrocyte-derived VEGF-A, MMP-9, CXCL-1, and MCP-1 levels in ischemic brain tissues from rats subjected to middle cerebral artery occlusion. Ex-4 reduced the activation of the JAK2/STAT3 signaling pathway in astrocytes following OGD. CONCLUSION: Based on these findings, ischemia-induced inflammation and BBB breakdown can be improved by Ex-4 through an astrocyte-dependent manner.

6.
J Cell Physiol ; 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31612476

RESUMO

Emerging evidence suggests that microRNA plays a pivotal role in cell proliferation. Our previous research has certified that miR-146a attenuates osteoarthritis through the regulation of cartilage homeostasis. However, little information about the function of miR-146a in bone marrow-derived mesenchymal stem cells (BMSCs) proliferation and the underlying mechanism was available. Therefore, this study aims at investigating the role of miR-146a on the proliferation of BMSCs and the possible mechanisms involved. The function of miR-146a on BMSCs proliferation was studied through overexpression and knockdown of miR-146a or the indicated long noncoding RNAs (lncRNAs) in BMSCs and then the proliferation rate of the BMSCs were detected by Cell Counting Kit-8 assay, colony formation assay. Besides, flow cytometry was used to test the cell cycle state of BMSCs modified by overexpression or knockdown of miR-146a or lncRNA EPB41L4A-AS1 (EPB41L4A Antisense RNA 1) and small nucleolar RNA host gene 7 (SNHG7). The expression level of marker genes involved in modulating cell proliferation was evaluated by quantitative polymerase chain reaction and western blot analysis. We discovered that the knockdown of miR-146a significantly promoted BMSCs proliferation. Moreover, miR-146a could bind to and inhibit endogenous expression of EPB41L4A-AS1 and SNHG7. Further study demonstrated that overexpression of EPB41L4A-AS1 and SNHG7 significantly enhanced proliferation of BMSCs. For the first time, we certified that miR-146a suppressed BMSCs proliferation, but EPB41L4A-AS1 and SNHG7 promoted BMSCs proliferation in the present study. Mechanistically, miR-146a significantly inhibited BMSCs proliferation partly through miR-146a/EPB41L4A-AS1 SNHG7/cell proliferation signaling pathway axis.

7.
J Xray Sci Technol ; 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31594279

RESUMO

BACKGROUND: Optical coherence tomography (OCT) is a non-invasive diagnosing tool used in clinics. Due to its high resolution (<10um), it is appropriate for the early detection of tiny infections. It has been widely used in diagnosis and treatment of diseases, evaluation of therapeutic efficacy, and monitoring of various physiological and pathological processes. OBJECTIVE: To systemically review literature to summarize the clinic application of OCT in recent years. METHODS: For clinic applications that OCT has been applied, we selected studies that describe the most relevant works. The discussion included: 1) which tissue could be used in the OCT detection, 2) which character of different tissue could be used as diagnosing criteria, 3) which diseases and pathological process have been diagnosed or monitored using OCT imaging, and 4) the recent development of clinic OCT diagnosing. RESULTS: The literature showed that the OCT had been listed as a routine test choice for ophthalmic diseases, while the first commercial product for cardiovascular OCT detection had gotten clearance. Meanwhile, as the development of commercial benchtop OCT equipment and tiny fiber probe, the commercial application of OCT in dermatology, dentistry, gastroenterology and urology also had great potential in the near future. CONCLUSIONS: The analysis and discussions showed that OCT, as an optical diagnosing method, has been used successfully in many clinical fields, and has the potential to be a standard inspection method in several clinic fields, such as dermatology, dentistry and cardiovascular.

8.
Artigo em Inglês | MEDLINE | ID: mdl-31618815

RESUMO

Microbial electrochemical technology provides an inexhaustible supply of electron acceptors, allowing electroactive microorganisms to generate biocurrent and accelerate the removal of organics. The treatment of wastewater contaminated by butachlor, which is a commonly used chloroacetamide herbicide in paddy fields, is a problem in agricultural production. In this study, butachlor was found to be removed efficiently (90 ± 1%) and rapidly (one day) in constructed single-chamber microbial fuel cells (MFCs). After the addition of sodium acetate to MFCs with butachlor as the sole carbon source, electricity generation was recovered instead of increasing the degradation efficiency of butachlor. Meanwhile, the microbial community structure was changed in anodic and cathodic biofilms after the addition of butachlor, following the bioelectrochemical degradation of butachlor. High-throughput sequencing showed the proliferation of Paracoccus and Geobacter in MFCs with butachlor as the sole carbon source and of Thauera butanivorans in MFCs with butachlor and sodium acetate as concomitant carbon sources. These species possess the ability to oxidize different substituents of butachlor and have important potential use for the bioremediation of wastewater, sediments, and soils.

9.
Photodiagnosis Photodyn Ther ; 28: 343-345, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31614224

RESUMO

Hidradenitis suppurativa (HS) is a type of chronic suppurative inflammatory reaction of the hair follicles characterized by recurrent dermal abscesses, sinus tracts and scars. In this report, one case of severe hypertrophic scar induced by facial HS achieved resolution of skin lesions after combined treatment with high concentration single-dose 5-aminolevulinic acid photodynamic therapy (5-ALA PDT). No recurrence was observed up to eleven months of follow-up. The 5-ALA PDT based treatment could improve the severe hypertrophic scar induced by HS in an effective and safe manner.

10.
FASEB J ; 33(12): 14254-14269, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31648561

RESUMO

Twist-related protein 2 (TWIST2) is identified as a basic helix-loop-helix (b-HLH) transcription repressor by dimerizing with other b-HLH proteins. The significance of TWIST2 has been emphasized in various tumors; however, few studies report its functions in metabolism and metabolic diseases. Here we aimed to explore the novel role and regulation mechanism of TWIST2 in hepatic steatosis. Our results showed that Twist2 knockdown caused mice obesity, insulin resistance, and hepatic steatosis, which were accompanied with inflammation, endoplasmic reticulum stress, and mitochondrial dysfunction. In vitro, TWIST2 overexpression ameliorated hepatocellular steatosis, inhibited inflammation, and improved mitochondrial content and function with a fibroblast growth factor 21 (FGF21)-dependent pattern. NF-κB negatively regulated FGF21 transcription by directly binding to FGF21 promoter DNA, which was eliminated by TWIST2 overexpression by inhibiting NF-κB expression and translocation to nucleus. TWIST2 overexpression decreased intracellular reactive oxygen species level, increased mitochondrial DNA and biogenesis, and enhanced ATP production and antioxidation ability. Additionally, TWIST2 expression was repressed by insulin-targeting sterol regulatory element-binding protein 1c (SREBP1c) and forkhead box protein O1 and was enhanced by dexamethasone targeting Krüppel-like factor 15, which directly interacted with Twist2 promoter DNA. Together, our studies identify an important role and regulation mechanism of TWIST2 in maintaining hepatic homeostasis by ameliorating steatosis, inflammation, and oxidative stress via the NF-κB-FGF21 or SREBP1c-FGF21 pathway, which may provide a new therapeutic scheme for nonalcoholic fatty liver disease.-Zhou, L., Li, Q., Chen, A., Liu, N., Chen, N., Chen, X., Zhu, L., Xia, B., Gong, Y., Chen, X. KLF15-activating Twist2 ameliorated hepatic steatosis by inhibiting inflammation and improving mitochondrial dysfunction via NF-κB-FGF21 or SREBP1c-FGF21 pathway.

11.
J Ethnopharmacol ; : 112317, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31629862

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Arnebiae Radix, a common herbal medicine in China, is often utilized to treat blood-heat syndrome and has been reported to exert an effect on the heart. AIM OF THE STUDY: The combination of acetylcholine (Ach) and CaCl2 has been widely used to induce atrial fibrillation (AF) in animals. However, whether Arnebiae Radix displays any preventive action on Ach-CaCl2 induced AF in rats remains uncertain. In our study, we attempted to investigate the protective effects of Arnebiae Radix on Ach-CaCl2 induced AF compared to amiodarone, which was employed as the positive control. MATERIALS AND METHODS: To establish the AF model, SD rats were treated with a mixture of 0.1 mL/100 g Ach-CaCl2 (60 µg/mL Ach and 10 mg/mL CaCl2) by tail vein injection for 7 days. Rats were also given a gavage of Arnebiae Radix (0.18 g/mL) one week before or concurrently with the establishment of the AF model. At the end of the experimental period, the induction, duration and timing of AF were monitored using electrocardiogram recordings. Left atrial tissues were stained to observe the level of fibrosis. Electrophysiological measurements were used to examine atrial size and function. RESULTS: In Ach-CaCl2-induced AF rats, Arnebiae Radix decreased AF induction, duration and susceptibility to AF. In addition, Arnebiae Radix significantly reduced atrial fibrosis and inhibited atrial enlargement induced by Ach-CaCl2. Moreover, there was an apparent improvement in cardiac function in the Arnebiae Radix-treated group. CONCLUSIONS: Our findings indicate that Arnebiae Radix treatment can attenuate Ach-CaCl2-induced atrial injury and serve as an effective therapeutic strategy for the treatment of AF in the future.

12.
Am J Surg ; 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31526512

RESUMO

BACKGROUND: The purpose of this study was to examine the reliability and the validity of the new surgical entrustable professional activities (SEPAs) instruments. METHODS: A prospective evaluation of six procedure-specific SEPAs instruments derived from the validated OPRS evaluation tools was conducted in 2018. Each instrument includes an open-ended feedback item and a series of Likert-Scale rating items. Attending, resident and a constant 3rd surgeon-observer completed the same evaluation for the observed case within 3 days of each evaluated operation. RESULTS: 40 cases performed by 10 residents and 11 attending surgeons were observed and evaluated. The SEPAs instruments were supported by strong validity evidence. Factor analysis revealed three latent variables are consistent with the core construct of SEPAs instrument. Internal reliability was high with Cronbach's α ranging from 0.84 to 0.94 across the six procedures. Test-retest reliability varied from 0.74 to 0.93 in the study sample. CONCLUSIONS: The SEPAs instruments are reliable and valid tools for assessment of crucial aspects of resident learning and surgical entrustable professional activities that lead to entrustment and eventually surgical autonomy.

13.
Mater Sci Eng C Mater Biol Appl ; 105: 110063, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546412

RESUMO

Artificial dermal scaffolds, which are made of natural or synthetic materials, can improve new blood vessel formation, cell migration and cell proliferation after being implanted into wounds, and they degrade slowly, playing an important role in dermal reconstruction and scar inhibition, finally achieving the goal of wound healing and functional reconstruction. Although these scaffolds have been widely used in clinical applications, biomaterial-associated infection is a deficiency or even a life-threatening problem that must be addressed, as it greatly affects the survival of the scaffolds. The gallium ion (Ga3+) is a novel metallic antimicrobial whose broad-spectrum antimicrobial properties against most bacteria encountered in burn wound infections have been confirmed, and it has been proposed as a promising candidate to prevent implant-associated infections. In this study, a gallium-loaded antimicrobial artificial dermal scaffold was successfully prepared by gallium ions and a collagen solution. The characterization results showed a porous structure with pore sizes ranging from 50 to 150 µm and a large porosity value of 97.4%. The enzymatic degradation rate in vitro was 19 and 28% after 12 and 24 h, respectively. In vitro antimicrobial testing revealed that the 1 h antibacterial rate against Staphylococcus aureus and Pseudomonas aeruginosa was close to 90%, which indicated its great antimicrobial activity. The results of the cytological evaluation showed slight effect on cell proliferation, with a relative growth rate (RGR) value of 80% and great cytocompatibility with cultured cells according to laser scanning confocal microscopy (LSCM) and scanning electron microscope (SEM). Furthermore, the successful prevention of wound infections in SD rats was confirmed with an in vivo antimicrobial evaluation, and the artificial dermal scaffolds also demonstrated great biocompatibility. This gallium-loaded antimicrobial artificial dermal scaffold exerted excellent antimicrobial activity and great biosafety, warranting further research for future clinical applications.

14.
Dalton Trans ; 48(38): 14467-14477, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31528897

RESUMO

Herein, three polypyrrole-based nanohybrids were designed and prepared via a nucleophilic substitution reaction, i.e., peripherally substituted porphyrin-functionalized PPy (TPP-PPy), axially coordinated metal-porphyrin-functionalized PPy (SnTPP-PPy), and polypyrrole ternary nanohybrids co-functionalized with peripherally substituted porphyrins and axially coordinated metal-porphyrins (TPP-PPy-SnTPP). The TPP-PPy, SnTPP-PPy and TPP-PPy-SnTPP nanohybrids exhibited improved nonlinear optical and optical limiting performances when compared to the individual PPy and porphyrins under 4 ns, 532 nm laser pulses. Their improved optical nonlinearities were ascribed to a combination of mechanisms and efficient charge transfer effect between the porphyrins and PPy. The charge transfer effect between the porphyrins and PPy was confirmed by UV-vis absorption, fluorescence and electrochemical impedance spectroscopy. The TPP-PPy-SnTPP ternary nanohybrid exhibited the best nonlinear absorption, nonlinear refraction and optical limiting performances because of more effective charge transfer effect, which provides a new avenue for the development of polypyrrole-porphyrin systems in the fields of nonlinear optics and optoelectronic devices.

15.
Oxid Med Cell Longev ; 2019: 5738368, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31485296

RESUMO

Diabetic foot ulcers (DFUs), the most serious complication of diabetes mellitus, can induce high morbidity, the need to amputate lower extremities, and even death. Although many adjunctive strategies have been applied for the treatment of DFUs, the low treatment efficiency, potential side effects, and high cost are still huge challenges. Recently, nanomaterial-based drug delivery systems (NDDSs) have achieved targeted drug delivery and controlled drug release, offering great promises in various therapeutics for diverse disorders. Additionally, the radial extracorporeal shock wave (rESW) has been shown to function as a robust trigger source for the NDDS to release its contents, as the rESW harbors a potent capability in generating pressure waves and in creating the cavitation effect. Here, we explored the performance of oxygen-loaded nanoperfluorocarbon (Nano-PFC) combined with the rESW as a treatment for DFUs. Prior to in vivo assessment, we first demonstrated the high oxygen affinity in vitro and great biocompatibility of Nano-PFC. Moreover, the rESW-responsive oxygen release behavior from oxygen-saturated Nano-PFC was also successfully verified in vitro and in vivo. Importantly, the wound healing of DFUs was significantly accelerated due to improved blood microcirculation, which was a result of rESW therapy (rESWT), and the targeted release of oxygen into the wound from oxygen-loaded Nano-PFC, which was triggered by the rESW. Collectively, the oxygen-saturated Nano-PFC and rESW provide a completely new approach to treat DFUs, and this study highlights the advantages of combining nanotechnology with rESW in therapeutics.

16.
Adv Mater ; : e1902434, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31364219

RESUMO

Sensory memory, formed at the beginning while perceiving and interacting with the environment, is considered a primary source of intelligence. Transferring such biological concepts into electronic implementation aims at achieving perceptual intelligence, which would profoundly advance a broad spectrum of applications, such as prosthetics, robotics, and cyborg systems. Here, the recent developments in the design and fabrication of artificial sensory memory devices are summarized and their applications in recognition, manipulation, and learning are highlighted. The emergence of such devices benefits from recent progress in both bioinspired sensing and neuromorphic engineering technologies and derives from abundant inspiration and benchmarks from an improved understanding of biological sensory processing. Increasing attention to this area would offer unprecedented opportunities toward new hardware architecture of artificial intelligence, which could extend the capabilities of digital systems with emotional/psychological attributes. Pending challenges are also addressed to aspects such as integration level, energy efficiency, and functionality, which would undoubtedly shed light on the future development of translational implementations.

17.
J Colloid Interface Sci ; 556: 159-171, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31445445

RESUMO

In this contribution, two constituent-tunable metallophthalocyanine covalent organic polymers (MPc-COPs) covalently attached to graphene oxide (GO-PcP 1 and GO-PcP 2) were rationally designed and fabricated for optoelectronics and electrocatalysis. The resultant GO-PcP nanohybrids exhibit markedly enhanced nonlinear optical and optical limiting performances over those of their components and physical mixtures at 532 nm in the nanosecond pulse range. The optical nonlinearity can be further optimized by tuning the linkage type between the four-branched tetraamine metallophthalocyanine units. The hydrogen evolution reaction (HER) is investigated by linear sweep voltammetry in a 0.5-M H2SO4 aqueous solution. Under optimal conditions, the overpotentials needed to reach 1 mA cm-2 are measured as 237 and 210 mV for GO-PcP 1 and GO-PcP 2, respectively, which places GO-PcP 2 as the best metallophthalocyanine polymer-based HER catalyst to be reported in the literature. The improved performances were ascribed to the positive synergistic effects between MPc-COPs and GO. Notably, the present study introduces a new strategy for the precise preparation of MPc-COP-based nanomaterials while exploring their applications to develop highly efficient optical limiters and electrocatalysts.

18.
J Am Chem Soc ; 141(36): 14038-14042, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31448603

RESUMO

Sluggish interfacial kinetics leading to considerable loss of energy and power capabilities at subzero temperatures is still a big challenge to overcome for Li-ion batteries operating under extreme environmental conditions. Herein, using LiMn2O4 as the model system, we demonstrated that nickel surface doping to construct a new interface owning lower charge transfer energy barrier, could effectively facilitate the interfacial process and inhibit the capacity loss with decreased temperature. Detailed investigations on the charge transfer process via electrochemical impedance spectroscopy and density functional theory calculation, indicate that the interfacial chemistry tuning could effectively lower the activation energy of charge transfer process by nearly 20%, endowing the cells with ∼75.4% capacity at -30 °C, far surpassing the hardly discharged unmodified counterpart. This control of surface chemistry to tune interfacial dynamics proposes insights and design ideas for batteries to well survive under thermal extremes.

19.
Theranostics ; 9(15): 4265-4286, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31285761

RESUMO

Periodontal ligament stem cells (PDLSCs) can repair alveolar bone defects in periodontitis in a microenvironment context-dependent manner. This study aimed to determine whether different extracellular matrices (ECMs) exert diverse effects on osteogenic differentiation of PDLSCs and accurately control alveolar bone defect repair. Methods: The characteristics of PDLSCs and bone marrow mesenchymal stem cells (BMSCs) with respect to surface markers and multi-differentiation ability were determined. Then, we prepared periodontal ligament cells (PDLCs)-derived and bone marrow cells (BMCs)-derived ECMs (P-ECM and B-ECM) and the related decellularized ECMs (dECMs). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and protein mass spectrometry were used to distinguish the ECMs. The expression of Type IV collagen A2 (COL4A2) in the ECMs was inhibited by siRNA or activated by lentiviral transduction of relevant cells. The stemness, proliferation, and differentiation of PDLSCs were determined in vitro in different dECMs. For the in vivo analysis, different dECMs under the regulation of COL4A2 mixed with PDLSCs and Bio-Oss bone powder were subcutaneously implanted into immunocompromised mice or in defects in rat alveolar bone. The repair effects were identified by histological or immunohistochemical staining and micro-CT. Results: B-dECM exhibited more compact fibers than P-dECM, as revealed by TEM, SEM, and AFM. Protein mass spectrometry showed that COL4A2 was significantly increased in B-dECM compared with P-dECM. PDLSCs displayed stronger proliferation, stemness, and osteogenic differentiation ability when cultured on B-dECM than P-dECM. Interestingly, B-dECM enhanced the osteogenic differentiation of PDLSCs to a greater extent than P-dECM both in vitro and in vivo, whereas downregulation of COL4A2 in B-dECM showed the opposite results. Furthermore, the classical Wnt/ß-catenin pathway was found to play an important role in the negative regulation of osteogenesis through COL4A2, confirmed by experiments with the Wnt inhibitor DKK-1 and the Wnt activator Wnt3a. Conclusion: These findings indicate that COL4A2 in the ECM promotes osteogenic differentiation of PDLSCs through negative regulation of the Wnt/ß-catenin pathway, which can be used as a potential therapeutic strategy to repair bone defects.

20.
Phys Rev Lett ; 122(23): 233902, 2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31298874

RESUMO

Recently, higher-order topological phases that do not obey the usual bulk-edge correspondence principle have been introduced in electronic insulators and brought into classical systems, featuring in-gap corner or hinge states. In this Letter, using near-field scanning measurements, we show the direct observation of corner states in second-order topological photonic crystal slabs consisting of periodic dielectric rods on a perfect electric conductor. Based on the generalized two-dimensional Su-Schrieffer-Heeger model, we show that the emergence of corner states roots in the nonzero edge dipolar polarization instead of the nonzero bulk quadrupole polarization. We demonstrate the topological transition of two-dimensional Zak phases of photonic crystal slabs by tuning intracell distances between two neighboring rods. We also directly observe in-gap one-dimensional edge states and zero-dimensional corner states in the microwave regime. Our work presents that the photonic crystal slab is a powerful platform to directly observe topological states and paves the way to study higher-order photonic topological insulators.

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