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1.
Proc Natl Acad Sci U S A ; 119(7)2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35145035

RESUMO

The nuclear receptors liver X receptor (LXR) α and ß play crucial roles in hepatic metabolism. Many genes induced in response to pharmacologic LXR agonism have been defined; however, the transcriptional consequences of loss of LXR binding to its genomic targets are less well characterized. Here, we addressed how deletion of both LXRα and LXRß from mouse liver (LXR double knockout [DKO]) affects the transcriptional regulatory landscape by integrating changes in LXR binding, chromatin accessibility, and gene expression. Many genes involved in fatty acid metabolism showed reduced expression and chromatin accessibility at their intergenic and intronic regions in LXRDKO livers. Genes that were up-regulated with LXR deletion had increased chromatin accessibility at their promoter regions and were enriched for functions not linked to lipid metabolism. Loss of LXR binding in liver reduced the activity of a broad set of hepatic transcription factors, inferred through changes in motif accessibility. By contrast, accessibility at promoter nuclear factor Y (NF-Y) motifs was increased in the absence of LXR. Unexpectedly, we also defined a small set of LXR targets for direct ligand-dependent repression. These genes have LXR-binding sites but showed increased expression in LXRDKO liver and reduced expression in response to the LXR agonist. In summary, the binding of LXRs to the hepatic genome has broad effects on the transcriptional landscape that extend beyond its canonical function as an activator of lipid metabolic genes.


Assuntos
Benzoatos/farmacologia , Benzilaminas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Receptores X do Fígado/metabolismo , Fígado/metabolismo , Animais , Regulação da Expressão Gênica/fisiologia , Receptores X do Fígado/agonistas , Receptores X do Fígado/genética , Camundongos , Camundongos Knockout
2.
Angew Chem Int Ed Engl ; 63(40): e202410383, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-38922734

RESUMO

Hydrogel actuators with complex 3D initial shapes show numerous important applications, but it remains challenging to fabricate such actuators. This article describes a polyelectrolyte-based strategy for modulating small-scale internal stresses within hydrogels to construct complex actuators with tailored 3D initial shapes. Introducing polyelectrolytes into precursor solutions significantly enhances the volume shrinkage of hydrogel networks during polymerization, allowing us to modulate internal stresses. Photopolymerization of these polyelectrolyte-containing solutions through a mask produces mechanically strong hydrogel sheets with large patterned internal stresses. Consequently, these hydrogel sheets attain complex 3D initial shapes at equilibrium, in contrast to the planar initial configuration of 2D actuators. We demonstrate that these 3D actuators can reversibly transform into other 3D shapes (i.e., 3D-to-3D shape transformations) in response to external stimuli. Additionally, we develop a predictive model based on the Flory-Rehner theory to analyze the polyelectrolyte-mediated shrinking behaviors of hydrogel networks during polymerization, allowing precise modulation of shrinkage and internal stress. This polyelectrolyte-boosted shrinking mechanism paves a route to the fabrication of high-performance 3D hydrogel actuators.

3.
J Am Chem Soc ; 145(13): 7548-7558, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36947220

RESUMO

Electrophilic addition to alkenes is a textbook-taught reaction, yet it is not always possible to control the regioselectivity of addition to unsymmetrical 1,2-disubstituted substrates. We report the observation and applications of the ß-boron effect that accounts for high regioselectivity in electrophilic addition reactions to allylic MIDA (N-methyliminodiacetic acid) boronates. While the well-established ß-silicon effect bears partial resemblance to the observed reactivity, the silyl group is typically lost during functionalization. In contrast, the boryl moiety is retained in the product when B(MIDA) is used as the nucleophilic stabilizer. Mechanistic studies elucidate the origin of this effect and demonstrate how σ(C-B) hyperconjugation helps stabilize the incipient carbocation. This transformation represents a rare example of the stereospecific hydrohalogenation of secondary allyl MIDA-boronates that proceeds in a syn-fashion.

4.
Opt Express ; 31(5): 7200-7211, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36859856

RESUMO

Practical realization of quantum repeaters requires quantum memories with high retrieval efficiency, multi-mode storage capacities, and long lifetimes. Here, we report a high-retrieval-efficiency and temporally multiplexed atom-photon entanglement source. A train of 12 write pulses in time is applied to a cold atomic ensemble along different directions, which generates temporally multiplexed pairs of Stokes photons and spin waves via Duan-Lukin-Cirac-Zoller processes. The two arms of a polarization interferometer are used to encode photonic qubits of 12 Stokes temporal modes. The multiplexed spin-wave qubits, each of which is entangled with one Stokes qubit, are stored in a "clock" coherence. A ring cavity that resonates simultaneously with the two arms of the interferometer is used to enhance retrieval from the spin-wave qubits, with the intrinsic retrieval efficiency reaching 70.4%. The multiplexed source gives rise to a ∼12.1-fold increase in atom-photon entanglement-generation probability compared to the single-mode source. The measured Bell parameter for the multiplexed atom-photon entanglement is 2.21(2), along with a memory lifetime of up to ∼125 µs.

5.
Small ; 18(2): e2104440, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34738711

RESUMO

The intellectualization and complication of existing self-shaping materials are limited by the inseparable monotonic relationship between their deformation rate and deformation degree (i.e., a higher deformation rate is accompanied by a high deformation degree). This causes that they can only deform from 2D to 3D states. Here, a simple yet versatile strategy to decouple the monotonic correlation between the deformation rate and deformation degree of self-shaping hydrogels is presented for achieving complex deformations from 2D to temporary 3D to 3D (2D-to-4D). It is demonstrated that when the gradient hydrogels prepared by photopolymerization possess dense polymer networks, the local regions with a high deformation rate can exhibit a low deformation degree. The resulting hydrogels can thus deform in a novel 2D-to-4D mode under external stimuli. During the deformation, they first transform into the temporary shapes induced by the local deformation rate difference, and then transform into the final shapes determined by the local deformation degree difference. Through controlling the ultraviolet irradiation direction and time to precisely program the local gradients of self-shaping hydrogels, they can be designed to produce various unprecedented yet controllable 2D-to-4D shape evolutions on demand, such as transformable origami, sequential gesture actions in finger-guessing games, mobile octopuses, time switch, etc.


Assuntos
Hidrogéis , Polímeros
6.
Soft Matter ; 18(19): 3748-3755, 2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35506704

RESUMO

Self-wrinkling hydrogels enable various engineering and biomedical applications. The major challenge is to couple the self-wrinkling technologies and enhancement strategies, so as to get rid of the poor mechanical properties of existing self-wrinkling gels. Herein we present a facile diffusion-complexation strategy for constructing strong and ultratough self-wrinkling polyelectrolyte hydrogels with programmable wrinkled structures and customizable 3D configurations. Driven by the diffusion of low-molecular-weight chitosan polycations into the polyanion hydrogels, the high-modulus polyelectrolyte complexation shells can form directly on the hydrogel surface. Meanwhile, the polyanion hydrogels deswell/shrink due to the low osmotic pressure, which applies an isotropous surface compressive stress for inducing the formation of polygonal wrinkled structures. When the diffusion-complexation reaction occurs on a pre-stretched hydrogel sheet, the long-range ordered wrinkled structures can form during the springback/recovery of the hydrogel matrix. Moreover, through controlling the regions of diffusion-complexation reaction on the pre-stretched hydrogels, they can be spontaneously transformed into various 3D configurations with ordered wrinkled structures. Notably, because of the introduction of plenty of electrostatic binding (i.e., sacrificial bonds), the as-prepared self-wrinkling gels possess outstanding mechanical properties, far superior to the reported ones. This diffusion-complexation strategy paves the way for the on-demand design of high-performance self-wrinkling hydrogels.


Assuntos
Quitosana , Envelhecimento da Pele , Hidrogéis/química , Polieletrólitos
7.
Angew Chem Int Ed Engl ; 60(37): 20294-20300, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34265152

RESUMO

Emerging asymmetric ionic membranes consisting of two different porous membranes show great superiority in harvesting clean and renewable osmotic energy. The main barriers constraining their applications are incompatible interfaces and a low interfacial ionic transport efficiency, which are detrimental to the long-term stability and improvement of the power density. Here, continuous-gradient all-polysaccharide polyelectrolyte hydrogel membranes prepared by ultrafast reaction/diffusion have been demonstrated to enable high-performance osmotic energy conversion. Besides an inherent high ion conductivity and excellent ion selectivity, the anti-swelling polyelectrolyte gradient membranes preserve the ionic diode effect of the asymmetric membranes to facilitate one-way ion diffusion but circumvent adverse interfacial effects. In consequence, they can present ultrahigh power densities of 7.87 W m-2 by mixing seawater and river water, far superior to state-of-the-art membranes.

8.
Angew Chem Int Ed Engl ; 60(7): 3454-3458, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33078900

RESUMO

α-Haloboronates are useful organic synthons that can be converted to a diverse array of α-substituted alkyl borons. Methods to α-haloboronates are limiting and often suffer from harsh reaction conditions. Reported herein is a photochemical radical C-H halogenation of benzyl N-methyliminodiacetyl (MIDA) boronates. Fluorination, chlorination, and bromination reactions were effective by using this protocol. Upon reaction with different nucleophiles, the C-Br bond in the brominated product could be readily transformed to a series of C-C, C-O, C-N, C-S, C-P, and C-I bonds, some of which are difficult to forge with α-halo sp2 -B boronate esters. An activation effect of B(MIDA) moiety was found.

9.
Lasers Med Sci ; 35(8): 1811-1819, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32277405

RESUMO

Pulsed dye laser (PDL) at the wavelength of 595 nm is the common choice for the treatment of port-wine stains (PWSs). In this study, the efficacy of 595-nm PDL in treatment of PWSs in Chinese patients was investigated. A follow-up visit was performed on 261 Fitzpatrick skin type II-III Chinese patients with PWS who received more than two treatments with 595-nm PDL. Based on cosmetic improvement, treatment response was graded as follows: complete, if color blanching was > 90%; significant, if color blanching was 60-90%; moderate, if color blanching was 30-60%; and poor, if color blanching was < 30%. The efficacy of laser treatment on patients of different treatment numbers, ages, lesion locations, lesion colors, extents of hypertrophy, and laser pulse durations was evaluated. All patients improved following an average of almost 4 to 5 laser treatments. The earlier the intervention, the better the efficacy was. Lesions on cheek, neck, and forehead were better than that those on oral, eye periorbital, and nose areas. The purple group had a more excellent clearance, i.e., complete and significant clearance rate (53.6%), than the red group (36.1%). Treatment effect became worse as the extent of lesion hypertrophy increased. PWS lesions treated with short pulse durations of 0.45, 1.5, and 3 ms had better clearance (complete and significant clearance) rate of 56.5% than those treated with pulse durations of 6 ms or longer (34.8%). Pulsed dye laser with 595-nm laser equipped with dynamic cooling device is an effective option for the treatment of PWS in Chinese patients. Younger patients with lateral face position, larger vessel size (deeper color), and lesser hypertrophy received better clinical effect than the others. Treatment with short pulse duration of less than 3 ms for 4 to 5 times was recommended to treat PWS.


Assuntos
Lasers de Corante/uso terapêutico , Mancha Vinho do Porto/cirurgia , Adolescente , Adulto , China , Feminino , Humanos , Hipertrofia , Cinética , Masculino , Pessoa de Meia-Idade , Mancha Vinho do Porto/patologia , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
10.
Angew Chem Int Ed Engl ; 57(50): 16544-16548, 2018 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-30358035

RESUMO

Organofluorine compounds are widely used in pharmaceutical, agrochemical, and materials sciences. The syntheses and applications of fluorinated organoborons facilitate the rapid and modular assemblies of fluorine-containing molecules because of the versatility of C-B bonds in diverse chemical transformations. Reported herein is a migratory geminal difluorination of aryl-substituted alkenyl N-methyliminodiacetyl (MIDA) boronates using commercially available Py⋅HF as the fluorine source and hyperiodine as the oxidant. The protocol offers facile access to α- and ß-difluorinated alkylboron compounds, both of which have previously been challenging to prepare. Mild reaction conditions, broad substrate scope, good functional-group tolerance, and moderate to good yields were observed. The utility of these products is demonstrated by further transformations of the C-B bond into other valuable functional groups.

11.
BMC Nephrol ; 15: 142, 2014 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-25182190

RESUMO

BACKGROUND: MicroRNAs have been demonstrated to play an important role in the pathogenesis of diabetic nephropathy (DN). In this study, we investigated both the repertoire of miRNAs in the kidneys of patients with DN and their potential regulatory role in inflammation-mediated glomerular endothelial injury. METHODS: The miRNA expression profiling of the renal biopsy samples was performed by a microarray analysis; then, in situ hybridization and real-time polymerase chain reaction (PCR) were used to determine the localization and expression of two of the miRNAs significantly up-regulated in human DN kidney samples, miR-155 and miR-146a, in the kidney tissues from type 1 and type 2 DN rat models. Human renal glomerular endothelial cells (HRGECs) cultured under high-glucose conditions were transfected with miR-155 and miR-146a mimics, and the transforming growth factor (TGF)-ß1, tumor necrosis factor (TNF)-α, and nuclear factor (NF)-κB expressions were examined by western blot, real-time PCR, and an electrophoresis mobility shift assay. RESULTS: The expression of both miR-155 and miR-146a was increased more than fivefold in the kidney samples of the DN patients compared with the controls, and the miR-155 expression was closely correlated with the serum creatinine levels (R = 0.95, P = 0.004). During the induction and progression of the disease in type 1 and type 2 DN rat models, miR-155 and miR-146a were demonstrated to increase gradually. In vitro, high glucose induced the over-expression of miR-155 and miR-146a in the HRGECs, which, in turn, increased the TNF-α, TGF-ß1, and NF-κB expression. CONCLUSIONS: Taken together, these findings indicate that the increased expression of miR-155 and miR-146a in the DN patients and in the experimental DN animal models was found to contribute to inflammation-mediated glomerular endothelial injury.


Assuntos
Nefropatias Diabéticas/metabolismo , Endotélio Vascular/metabolismo , Mediadores da Inflamação/metabolismo , Glomérulos Renais/metabolismo , MicroRNAs/metabolismo , Adulto , Animais , Células Cultivadas , Nefropatias Diabéticas/patologia , Endotélio Vascular/patologia , Feminino , Humanos , Glomérulos Renais/patologia , Masculino , Pessoa de Meia-Idade , Ratos , Ratos Sprague-Dawley
12.
ACS Appl Mater Interfaces ; 16(19): 25462-25472, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38700267

RESUMO

The construction of surface microstructures (e.g., micropyramids and wrinkles) has been proven as the most effective means to boost the sensitivity of ionic skins (I-skins). However, the single-scale micronano patterns constructed by the common fabrication strategy generally lead to a limited pressure-response range. Here, a convenient repeated stretching/coordinating/releasing strategy is developed to controllably construct multiple graded wrinkles on the polyelectrolyte hydrogel-based I-skins for increasing their sensitivity over a broad pressure range. We find that the small wrinkles allow for high sensitivity yet small pressure detection range, while the large wrinkles can reduce structural stiffening to generate large pressure-response range but incur limited sensitivity. The multiple graded wrinkles can combine the merits of both the small and large wrinkles to simultaneously improve the sensitivity and broaden the pressure-response range. In particular, the sensing performance of multiple-wrinkle-based I-skins substantially outperforms the superposition of the sensing performance of different single-wrinkle-based I-skins. As a proof of concept, the triple-wrinkle-based I-skins can provide an extremely high sensitivity of 17,309 kPa-1 and an ultrawide pressure detection range of 0.38 Pa to 372 kPa. The approach and insight contribute to the future development of I-skins with a broader pressure-response range and higher sensitivity.

13.
J Ethnopharmacol ; 321: 117539, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38056541

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Panax Notoginseng (PN) can disperse blood stasis, hemostasis, and detumescence analgesic, which can be used for hemoptysis, hematemesis and another traumatic bleeding, and it is known as "A miracle hemostatic medicine". Studies show that the chemical composition of PN is relatively comprehensive, however, its hemostatic active ingredients have not been fully clarified. AIM OF STUDY: This study aimed to clarify the hemostatic effective components group (HECG) of PN, provide a foundation for the assessment of PN's quality and its comprehensive development, and for further studies on the pharmacodynamic material basis of other Traditional Chinese Medicines (TCMs). MATERIALS AND METHODS: UPLC-MS was used to establish the fingerprint and identify the common peaks in 44 batches of PN extracts (PNE). In addition, the plasma recalcification time and in vitro coagulation time were measured. For spectrum-effect analysis, bivariate correlation analysis (BCA) and partial least squares regression analysis (PLSR) were used to screen the hemostasis candidate active monomers of PN. The monomers were prepared by combining several preparative chromatography techniques. The efficacy was verified by plasma recalcification time, in vitro coagulation time, and a rat model of gastric hemorrhage. RESULTS: A total of 30 common peaks and hemostatic efficacy indexes of 44 batches of PNE were obtained. A total of 18 components were positively correlated with the comprehensive coagulation index by two statistical methods. Six and eleven monomers were obtained respectively by chromatographic preparation and procurement, and one monomer was eliminated due to preparation difficulty and other reasons. Seven active monomers with direct hemostatic effect and one active monomer with synergistic hemostatic effect were screened through plasma recalcification time, and their combinations were used as candidate HECG for hemostatic effect verification. The results of in vitro experiments showed that plasma recalcification time and in vitro coagulation time were significantly reduced (P < 0.05) in the HECG group, compared to the PNE group. The results of in vivo experiment also indicated that the hemostatic effect of HECG was comparable to that of PNE and PN powder. CONCLUSION: The composition and efficacy of the HECG of PN were screened and verified using the spectral correlation method and in vivo and in vitro efficacy verification; the HECG included Dencichine, Ginsenoside Rg1, Ginsenoside Rd, Ginsenoside Rh1, Ginsenoside F1, Notoginsenoside R1, Notoginsenoside Ft1 and Notoginsenoside Fe. These results laid a foundation for the quality evaluation of PN and provided a reference for the basic research of pharmacodynamic material basis of other TCMs.


Assuntos
Ginsenosídeos , Hemostáticos , Panax notoginseng , Panax , Saponinas , Ratos , Animais , Ginsenosídeos/farmacologia , Panax notoginseng/química , Hemostáticos/farmacologia , Cromatografia Líquida , Espectrometria de Massas em Tandem , Hemostasia , Cromatografia Líquida de Alta Pressão/métodos , Panax/química , Saponinas/farmacologia
14.
Front Pharmacol ; 15: 1371504, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39101142

RESUMO

Objective: Subcutaneous Immunotherapy (SCIT) is the long-lasting causal treatment of allergic rhinitis (AR). How to enhance the adherence of patients to maximize the benefit of allergen immunotherapy (AIT) plays a crucial role in the management of AIT. This study aims to leverage novel machine learning models to precisely predict the risk of non-adherence of AR patients and related local symptom scores in 3 years SCIT. Methods: The research develops and analyzes two models, sequential latent-variable model (SLVM) of Stochastic Latent Actor-Critic (SLAC) and Long Short-Term Memory (LSTM). SLVM is a probabilistic model that captures the dynamics of patient adherence, while LSTM is a type of recurrent neural network designed to handle time-series data by maintaining long-term dependencies. These models were evaluated based on scoring and adherence prediction capabilities. Results: Excluding the biased samples at the first time step, the predictive adherence accuracy of the SLAC models is from 60% to 72%, and for LSTM models, it is 66%-84%, varying according to the time steps. The range of Root Mean Square Error (RMSE) for SLAC models is between 0.93 and 2.22, while for LSTM models it is between 1.09 and 1.77. Notably, these RMSEs are significantly lower than the random prediction error of 4.55. Conclusion: We creatively apply sequential models in the long-term management of SCIT with promising accuracy in the prediction of SCIT nonadherence in AR patients. While LSTM outperforms SLAC in adherence prediction, SLAC excels in score prediction for patients undergoing SCIT for AR. The state-action-based SLAC adds flexibility, presenting a novel and effective approach for managing long-term AIT.

15.
ACS Appl Mater Interfaces ; 15(46): 54018-54026, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37957821

RESUMO

The integration of photonic crystals and self-shaping actuators is a promising method for constructing powerful biomimetic color-changing actuators. The major barrier is that common photonic crystals generally block the transfer/orientation of monomers/fillers and hence hinder the formation of heterogeneous structures for programmed 3D deformations as well as degrade the deformation capacity and mechanical properties of actuators. Herein, we present the construction of complex and strong 3D color-changing hydrogel actuators by asymmetric photolithography based on soft, permeable photonic crystals. The soft permeable photonic crystals are assembled by hydrogel microspheres with an ultralow volume fraction. During the asymmetric photolithography, the monomers in precursor solutions can thus transfer freely to generate heterogeneous microstructures, spatially patterned internal stresses, and interpenetrating networks for programming the deformation trajectories and initial 3D configurations and enhancing mechanical properties of actuators. Various 3D color-changing hydrogel actuators (e.g., flower and scroll painting) are constructed for applications such as information encryption and display.

16.
Front Aging Neurosci ; 15: 1285549, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38076535

RESUMO

Background: Alzheimer's disease (AD) is a multifactorial neurodegenerative condition. The search for multi-target traditional Chinese medicines or ingredients for treating AD has attracted much attention. Corydalis rhizome (CR) is a traditional Chinese medicine. Its main components are alkaloids, which have therapeutic effects that can potentially be used for treating AD. However, no systematic study has been conducted to explore the anti-AD efficacy of CR, as well as its active compounds and mechanisms of action. Objective: The present study aimed to clarify CR's active constituents and its pharmacological mechanisms in treating AD. Methods: A D-galactose & scopolamine hydrobromide-induced AD mouse model was used and CR was administered orally. The prototypical alkaloid components were identified in the serum. The core components, key targets, and possible mechanisms of action of these alkaloids were revealed through network pharmacology. Molecular docking of the key target was performed. Finally, the mechanism was validated by lipopolysaccharide (LPS)-induced activation of BV2 microglia. Results: The results showed that CR improved anxiety-like behavior, spatial and non-spatial recognition, and memory capacity in AD mice. It also achieved synergistic AD treatment by modulating neurotransmitter levels, anti-neuroinflammation, and anti-oxidative stress. The core components that enhance CR's efficacy in treating AD are protoberberine-type alkaloids. The CR may induce the polarization of LPS-activated BV2 microglia from phenotype M1 to M2. This is partially achieved by modulating the IL-6/JAK2/STAT3 signaling pathway, which could be the mechanism by which CR treats AD through anti-inflammation. Conclusion: The present study provided a theoretical and experimental basis for the clinical application of CR in treating AD. It also provides information that aids the secondary development, and precise clinical use of CR.

17.
Polymers (Basel) ; 14(23)2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36501705

RESUMO

The skin, as the largest organ of human body, can use ions as information carriers to convert multiple external stimuli into biological potential signals. So far, artificial skin that can imitate the functionality of human skin has been extensively investigated. However, the demand for additional power, non-reusability and serious damage to the skin greatly limits applications. Here, we have developed a self-powered gradient hydrogel which has high temperature-triggered adhesion and room temperature-triggered easy separation characteristics. The self-powered gradient hydrogels are polymerized using 2-(dimethylamino) ethyl metharcylate (DMAEMA) and N-isopropylacrylamide (NIPAM) under unilateral UV irradiation. The prepared hydrogels achieve good adhesion at high temperature and detachment at a low temperature. In addition, according to the thickness-dependent potential of the gradient hydrogel, the hydrogels can also sense pressure changes. This strategy can inspire the design and manufacture of self-powered gradient hydrogel sensors, contributing to the development of complex intelligent artificial skin sensing systems in the future.

18.
Chem Sci ; 13(21): 6413-6417, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35733886

RESUMO

The selenium-π-acid-catalysis has received increasing attention as a powerful tool for olefin functionalization, but the regioselectivity is often problematic. Reported herein is a selenium-catalyzed regiocontrolled olefin transpositional chlorination and imidation reaction. The reaction outcome benefits from an allylic B(MIDA) substitution. And the stabilization of α-anion from a hemilabile B(MIDA) moiety was believed to be the key factor for selectivity. Broad substrate scope, good functional group tolerance and generally good yields were observed. The formed products were demonstrated to be valuable precursors for the synthesis of a wide variety of structurally complex organoborons.

19.
ACS Nano ; 16(3): 4714-4725, 2022 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-35188364

RESUMO

Human skin is the largest organ, and it can transform multiple external stimuli into the biopotential signals by virtue of ions as information carriers. Ionic skins (i-skins) that can mimic human skin have been extensively explored; however, the limited sensing capacities as well as the need of an extra power supply significantly restrict their broad applications. Herein, we develop self-powered humanlike i-skins based on gradient polyelectrolyte membranes (GPMs) that can directly and accurately perceive multiple stimuli. Prepared by a hydrogel-assisted reaction-diffusion method, the GPMs exhibit gradient-distributed charged groups across polymer networks, enabling one to generate a thickness-dependent and thermoresponsive self-induced potential in a hydrated situation and in a humidity-sensitive self-induced potential in a dehydrated/dried situation, respectively. Consequently, the GPM-based i-skins can precisely detect pressure, temperature, and humidity in a self-powered manner. The coupling of mechano-electric and thermo-electric effects inherent in GPMs provides a general strategy for developing innovative self-powered ion-based perception systems.


Assuntos
Hidrogéis , Pele , Eletricidade , Humanos , Íons , Polieletrólitos
20.
Materials (Basel) ; 15(16)2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-36013661

RESUMO

In the present study, Mo was added to Cu-15Ni-8Sn alloy as the fourth element to solve the limitation of service performance of the alloy by composition design. The phase composition, microstructure transformation and mechanical properties of Cu-15Ni-8Sn-xMo (x = 0.3, 0.9, 1.5 wt.%) alloy were systematically studied by simulation calculation and experimental characterization. The results show that the addition of Mo can improve the as-cast structure of Cu-15Ni-8Sn alloy and reduce segregation and Cu-Mo phase precipitates on the surface with the increase in Mo contents. During solution treatment, Mo can partially dissolve into the matrix, which may be the key to improving the properties of the alloy. Furthermore, the discontinuous precipitation of Sn can be effectively inhibited by adding the appropriate amount of Mo to Cu-15Ni-8Sn alloy, and the hardness of alloy does not decrease greatly after a long-time aging treatment. When Mo content is 0.9 wt.%, the alloy reaches the peak hardness of 384 HV at 4 h of aging. These results provide new ideas for composition optimization of Cu-15Ni-8Sn alloy.

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