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2.
Adv Mater ; : e2210854, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36621966

RESUMO

Atomically two-dimensional (2D) layered ferroelectric semiconductors, in which the polarization switching process occurs within the channel material itself, offer a new material platform that could drive electronic components towards structural simplification and high-density integration. Here, a room-temperature 2D layered ferroelectric semiconductor, bismuth oxychalcogenides (Bi2 O2 Se), is investigated with a thickness down to 7.3 nm (∼12 layers) and piezoelectric coefficient (d33 ) of 4.4 ± 0.1 pm V-1 . The random orientations and electrically-dependent polarization of the dipoles in Bi2 O2 Se are separately uncovered owing to the structural symmetry-breaking at room temperature. Specifically, the interplay between ferroelectricity and semiconducting characteristics of Bi2 O2 Se is explored on device-level operation, revealing the hysteresis behaviors and memory windows formation. Leveraging the ferroelectric polarization originating from Bi2 O2 Se, the fabricated device exhibits "smart" photoresponse tunability and excellent electronic characteristics, e.g., a high on/off current ratio > 104 and a large memory window to the sweeping range of 47% at VGS = ±5 V. These results demonstrate the synergistic combination of ferroelectricity with semiconducting characteristics in Bi2 O2 Se, laying the foundation for integrating sensing, logic and memory functions into a single material system that could overcome the bottlenecks in von Neumann architecture. This article is protected by copyright. All rights reserved.

3.
Radiol Med ; 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36627501

RESUMO

PURPOSE: To explore the characteristics of the hepatic fat content in athletes, and predict late gadolinium enhancement (LGE) based on magnetic resonance imaging-proton density fat fraction (MRI-PDFF). MATERIAL AND METHODS: From March 2020 to March 2021, 233 amateur athletes and 42 healthy sedentary controls were prospectively recruited. The liver fat content of four regions of interest (ROIs 1-4), the mean liver fat fraction (FF), cardiac function, and myocardium LGE were recorded, respectively. The values of ROIs 1-4 and FF were compared between athletes and controls. According to the liver fat content threshold for distinguishing athletes and controls, the cutoff total exercise time that induced a change in liver fat was obtained. The correlations among the liver fat content, cardiac function, and other parameters were analyzed. Moreover, the liver fat content was used to predict myocardium LGE by logistic regression. RESULTS: There were significant differences for the values of ROI 1, ROI 3, ROI 4, and FF between athletes and controls (allp< 0.05). The cutoff total exercise time for inducing a change in the liver fat content was 1680 h (area under the curve [AUC] = 0.593, specificity = 83.3,p< 0.05). Blood indexes, cardiac function, and basic clinical parameters were related to liver fat content (allp< 0.05). The prediction model for LGE had an AUC value of 0.829 for the receiver operator characteristic curve. CONCLUSION: MRI-PDFF could assess liver fat content and predict cardiac fibrosis in athletes for risk stratification and follow-up.

4.
Mol Neurobiol ; 2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36602702

RESUMO

Central post-stroke pain (CPSP) is a highly refractory form of central neuropathic pain that has been poorly studied mechanistically. Recent observations have emphasized the critical role of the spinal dorsal horn in CPSP. However, the underlying mechanisms remain unclear. In this study, rats were subjected to thalamic hemorrhage to investigate the role of spinal monocyte chemoattractant protein-1 (MCP-1) and C-C motif chemokine receptor 2 (CCR2) in the development of CPSP. Immunohistochemical staining and ELISA were used to assess the expression changes of c-Fos, Iba-1, GFAP, MCP-1, and CCR2 in the dorsal horn of the lumbar spinal cord following thalamic hemorrhage, and the involvement of spinal MCP-1 in CPSP was examined by performing intrathecal anti-MCP-1 mAb injection to neutralize the spinal extracellular MCP-1. We demonstrated that intra-thalamic collagenase microinjection induced persistent bilateral mechanical pain hypersensitivity and facilitated the spontaneous pain behaviors evoked by intraplantar bee venom injection. Accompanying CPSP, the expression of c-Fos, Iba-1, and GFAP in the lumbar spinal dorsal horn was significantly increased up to 28 days post-intra-thalamic collagenase microinjection. Intrathecal injection of minocycline and fluorocitrate dramatically reverses the bilateral mechanical pain hypersensitivity. Moreover, intra-thalamic collagenase microinjection dramatically induced the up-regulation of MCP-1 but had no effect on the expression of CCR2 in the bilateral lumbar spinal dorsal horn, and MCP-1 was primarily localized in the neuron. Intrathecal injection of anti-MCP-1 mAb was also able to reverse CPSP and reduce the expression of c-Fos, Iba-1, and GFAP in the lumbar spinal dorsal horn. These findings indicated that spinal MCP-1 contributes to CPSP by mediating the activation of spinal neurons and glial cells following thalamic hemorrhage stroke, which may provide insights into pharmacologic treatment for CPSP.

5.
J Thromb Haemost ; 21(1): 190-191, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36695388
6.
J Org Chem ; 2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36656018

RESUMO

A nickel-catalyzed three-component tandem radical cyclization reaction of aryl bromides with 1,3-enynes and aryl boric acids to construct γ-lactam-substituted allene derivatives has been described. This protocol provides lactam alkyl radicals through the free radical cyclization process, which can be effectively used to participate in the subsequent multicomponent coupling reaction so that 1,3-enynes could directly convert into corresponding poly-substituted allene compounds. In addition, this efficient method enjoys a broad substrate scope and provides a series of 1,5-difunctionalized allenes in a one-pot reaction.

7.
J Clin Med ; 12(2)2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36675653

RESUMO

(1) Background: For completely lower pole renal tumors, we compared the perioperative outcomes of robotic partial nephrectomy via transperitoneal and retroperitoneal approaches. (2) Methods: Complete lower pole renal tumors were defined as tumors that received 1 point for the "L" element of the R.E.N.A.L. and located at the lower pole of kidney. After confirming consistency in baseline characteristics, oncological and functional benefits were compared. Pentafecta achievement was used to represent the perioperative optimal outcome, followed by multivariate analysis of factors associated with the lack of pentafecta achievement. (3) Results: Among 151 patients identified, 116 (77%) underwent robotic partial nephrectomy via a transperitoneal approach and 35 (23%) via a retroperitoneal approach. Patients undergoing transperitoneal robotic partial nephrectomy experienced more blood loss than those undergoing retroperitoneal robotic partial nephrectomy (50 mL vs. 40 mL, p = 0.015). No significant differences were identified for operative time (120 min vs. 120 min), ischemia time (19 min vs. 20 min), positive surgical margins (0.0% vs. 2.86%), postoperative rate of complication (12.07% vs. 5.71%). No significant differences were identified in pathologic variables, eGFR decline in postoperative 12-month (3.9% vs. 5.4%) functional follow-up. Multivariate cox analysis showed that tumor size (OR: 0.523; 95% CI: 0.371-0.736; p < 0.001) alone was independently correlated to the achievement of pentafecta. (4) Conclusions: For completely lower pole renal tumors, transperitoneal and retroperitoneal robotic partial nephrectomy provide similar outcomes. These two surgical approaches remain feasible options for these cases.

8.
Pest Manag Sci ; 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36693781

RESUMO

BACKGROUND: Zeugodacus cucurbitae is an agricultural pest species with robust reproductive capabilities capable of causing extensive damage. The advent of novel male fertility-related pest control strategies has been an area of active entomological research focused on the sterile insect technique (SIT) strategy. RESULTS: RNA-Seq analyses were conducted using 16 tissue samples from adult male Z. cucurbitae, leading to the identification of 5338 genes that were differentially expressed between the testes and three other analyzed tissue types. Of these genes, 808 exhibited high levels of testis expression. A qPCR approach was used validate the expression of 10 of these genes selected at random, including ZcTSSK1 and ZcTSSK3, which are testis-specific serine/threonine protein kinase (TSSK) genes. Evaluation via a loss-of-function-based knockdown assay showed that the downregulation of either of these two genes in males was associated with significantly decreased egg hatching rates. In situ hybridization analyses revealed the expression of both of these transcripts in the transformation zone, and significant decreases in Z. cucurbitae sperm numbers were observed following dsRNA treatment. Together, these results suggested that inhibiting ZcTSSK1 and ZcTSSK3 expression was sufficient to alter male fertility in Z. cucurbitae. CONCLUSION: These transcriptional sequencing results provide a foundation for further efforts to clarify the regulators of Z. cucurbitae male fertility. These preliminary analyses of the functions of ZcTSSK family genes as regulators of spermatogenesis underscore their importance in the processes integral to male fecundity and their potential as targets for pest control efforts centered on the genetic manipulation of males. This article is protected by copyright. All rights reserved.

9.
J Transl Med ; 21(1): 9, 2023 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624452

RESUMO

BACKGROUNDS: Papillary thyroid cancer (PTC), which is often driven by acquired somatic mutations in BRAF genes, is the most common pathologic type of thyroid cancer. PTC has an excellent prognosis after treatment with conventional therapies such as surgical resection, thyroid hormone therapy and adjuvant radioactive iodine therapy. Unfortunately, about 20% of patients develop regional recurrence or distant metastasis, making targeted therapeutics an important treatment option. Current in vitro PTC models are limited in representing the cellular and mutational characteristics of parental tumors. A clinically relevant tool that predicts the efficacy of therapy for individuals is urgently needed. METHODS: Surgically removed PTC tissue samples were dissociated, plated into Matrigel, and cultured to generate organoids. PTC organoids were subsequently subjected to histological analysis, DNA sequencing, and drug sensitivity assays, respectively. RESULTS: We established 9 patient-derived PTC organoid models, 5 of which harbor BRAFV600E mutation. These organoids have been cultured stably for more than 3 months and closely recapitulated the histological architectures as well as mutational landscapes of the respective primary tumors. Drug sensitivity assays of PTC organoid cultures demonstrated the intra- and inter-patient specific drug responses. BRAFV600E inhibitors, vemurafenib and dabrafenib monotherapy was mildly effective in treating BRAFV600E-mutant PTC organoids. Nevertheless, BRAF inhibitors in combination with MEK inhibitors, RTK inhibitors, or chemotherapeutic agents demonstrated improved efficacy compared to BRAF inhibition alone. CONCLUSIONS: These data indicate that patient-derived PTC organoids may be a powerful research tool to investigate tumor biology and drug responsiveness, thus being useful to validate or discover targeted drug combinations.


Assuntos
Carcinoma Papilar , Neoplasias da Glândula Tireoide , Humanos , Câncer Papilífero da Tireoide/tratamento farmacológico , Câncer Papilífero da Tireoide/genética , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Proteínas Proto-Oncogênicas B-raf/genética , Radioisótopos do Iodo/uso terapêutico , Carcinoma Papilar/tratamento farmacológico , Carcinoma Papilar/genética , Mutação/genética , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Organoides/patologia
10.
Gene ; 859: 147199, 2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36657650

RESUMO

NR3C1-encoding glucocorticoid receptors have dual roles as RNA-binding protein and transcription factor. Recent studies revealed that NR3C1 might play an important role in the pathogenesis of PTSD (Post-traumatic stress disorder). However, its molecular mechanism remained unclear. In the present study, a neuronal cell model was constructed by transfecting a NR3C1-overexpressing plasmid pIRES-hrGFP-1a-NR3C1 or empty vector into HT22 cells. The changes in global transcription levels and alternative splicing events in HT22 cells after NR3C1 overexpression were analyzed by RNA sequencing. Compared with the empty vector control, the expression of inflammatory factors were differentially regulated by NR3C1, including genes involved in chemokine signal pathway, PI3K-Akt signal pathway, cytokine receptor interaction, neural ligand-receptor interaction and so on. In addition, NR3C1 regulated the alternative splicing of many genes involved in immune response, axon formation, stress response and inflammation. This study was the first to perform a transcriptome analysis of differential gene expression and alternative splicing in a NR3C1-overexpressing HT22 cell model. Our results suggested that NR3C1 could manipulate the expression of inflammatory transcription factors and their alternative splicing patterns, subsequently affecting the expression of downstream targets, may be leading to the onset of PTSD. This study will provide new insights in the NR3C1-mediated gene regulation in relation to PTSD.

11.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 40(2): 202-207, 2023 Feb 10.
Artigo em Chinês | MEDLINE | ID: mdl-36709941

RESUMO

OBJECTIVE: To analyze the correlation between the mRNA levels of breast cancer resistance protein (BCRP) and lung-specific X protein (LUNX) genes with pathological types and stages of patients with non-small cell lung cancer (NSCLC) and their significance for prognosis. METHODS: Eighty nine patients with NSCLC admitted to Huaihe Hospital of Henan University between June 2015 and June 2018 were recruited, with 55 patients with benign lung lesions admitted during the same period of time selected as the control group. The mRNA levels of BCRP and LUNX genes were detected in the peripheral blood samples from the two groups, and their correlation with the clinicopathological characteristics and prognosis of the patients was analyzed. RESULTS: The expression rates of BCRP and LUNX mRNA in the NSCLC group were significantly higher compared with the control group (P < 0.05). The level of BCRP mRNA of the NSCLC patients has correlated with the degree of differentiation and TNM staging (P < 0.05), but not with gender, age, smoking, pathological types and lymph node metastasis (P > 0.05). The level of LUNX mRNA of them has correlated with the degree of differentiation, TNM staging and lymph node metastasis (P < 0.05), but not with gender, age, smoking, and pathological types (P > 0.05). Compared with those with no expression, the overall survival rate of patients with BCRP and LUNX expression was significantly lower (P < 0.05). The degree of differentiation, TNM staging, lymph node metastasis, and expression of the BCRP and LUNX mRNA may all affect the prognosis of the patients. CONCLUSION: The levels of BCRP and LUNX mRNA in the peripheral blood of patients with NSCLC are significantly increased. The expression of BCRP mRNA is correlated with the degree of differentiation and TNM staging, whilst the expression of LUNX mRNA is correlated with the differentiation degree, TNM staging and lymph node metastasis. Both may be used as independent predictors for the prognosis of patients with NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , RNA Mensageiro/genética , Metástase Linfática , Proteínas de Neoplasias/genética , Glicoproteínas/genética , Fosfoproteínas/genética , Prognóstico , Biomarcadores Tumorais/genética
12.
Anal Chim Acta ; 1242: 340813, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36657896

RESUMO

Viscosity is an important component of cell microenvironment, and abnormal mitochondrial viscosity is associated with many diseases such as tumor and fatty liver. Herein, a near-infrared fluorescence probe (QX-V) based on quinoline-xanthene dye for detecting viscosity is constructed. In high viscosity medium, the free rotation of single bond is inhibited and the fluorescence is released. The probe shows high sensitivity together with good selectivity. Notably, QX-V has a long excitation wavelength (710 nm) and emission wavelength (786 nm). At the same time, the probe is a positively charged molecule that can target mitochondria. QX-V can not only distinguish cancer cells from normal cells, but also make a distinction between normal cells and fatty hepatocytes. In addition, QX-V is used to image viscosity abnormality in tumor-bearing mice. The probe also has a good ability to image viscosity abnormality caused by liver injury in fatty-liver mice.


Assuntos
Fígado Gorduroso , Neoplasias , Humanos , Camundongos , Animais , Corantes Fluorescentes/química , Viscosidade , Imagem Óptica/métodos , Mitocôndrias/química , Células HeLa , Fígado Gorduroso/patologia , Neoplasias/diagnóstico por imagem , Neoplasias/patologia
13.
ACS Appl Mater Interfaces ; 15(2): 3543-3557, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36622779

RESUMO

Multi stimuli-responsive aggregation-induced emission (AIE) active polymers have great application prospects in high-tech innovations. Herein, three types of tetraphenylethylene (TPE)-containing monomers were synthesized and utilized in preparing TPE-appended maleic anhydride terpolymers. After hydrolysis, the produced TPE-appended maleic acid terpolymers have identical linear charge densities but different "primary" structures, which created widely varied microenvironments around the carboxylate and TPE groups. Benefiting from the synergistic interaction of the TPE moiety and the terpolymer conformation change, the TPE-appended maleic acid terpolymers exhibited fluorescence changes in response to multi stimuli, including pH, ionic strength, Ca2+, and bovine serum albumin. On both the "signaling" and the "stimuli acceptor" sides, the multi stimuli-responsive fluorescence behavior was influenced markedly by the terpolymer primary structure. The fundamental insights gained in the present work are important for developing an efficient and versatile stimuli-responsive AIE-active polymer platform for chemo-sensing, bioimaging, and so on.


Assuntos
Polímeros Responsivos a Estímulos , Polímeros/química , Anidridos Maleicos
14.
J Pers Med ; 13(1)2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36675776

RESUMO

BACKGROUND: Signet ring cell carcinoma (SRCC) is a specific type of gastric cancer. The clinicopathological and molecular characteristics that can be used to predict the response to anti-PD-1 therapy for these patients are still not clear. METHODS: Patients with advanced SRCC who received first-line anti-PD-1-based treatment were enrolled in this study. The clinicopathological characteristics of these patients were obtained from their medical records. The molecular features of these patients were analyzed by means of a next-generation-sequencing-based panel. The predictive significance of clinicopathological and molecular features for efficacy was analyzed. RESULTS: A total of 71 patients with measurable lesions were included in this study, among which 46 patients had enough tissues for next-generation sequencing. The overall objective response rate (ORR) was 46.4%. ORR was significantly higher in mismatch repair (MMR)-deficient (dMMR) patients than in MMR-proficient (pMMR) patients, in patients with lymph node metastasis only than those with other metastasis sites, and in patients with an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 than with a PS of 1 or 2. The progression-free survival was significantly longer in patients with dMMR, lymph node metastasis only, PD-L1 combined positive score (CPS) ≥ 5, and CDH1 wild type. CONCLUSIONS: Several clinicopathological and molecular features are associated with anti-PD-1 treatment efficacy in SRCC, which might be used to identify patients who can benefit most from these therapies.

15.
J Phys Chem Lett ; : 954-964, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36688834

RESUMO

The structures of molecules and materials determine their functions. Understanding the structure and function relationship is the holy grail of molecular and materials sciences. However, the rational design of molecules and materials with desirable functions remains a grand challenge despite decades of efforts. A major obstacle is the lack of an intrinsic mathematical characteristic that attributes to a specific function. This work introduces persistent path topology (PPT) to effectively characterize directed networks extracted from functional units, such as constitutional isomers, cis-trans isomers, chiral molecules, Jahn-Teller isomerism, and high-entropy alloy catalysts. Path homology (PH) theory is utilized to decipher the role of mirror-symmetric sublattices that hinder the formation of periodic unit cells in amorphous solids. Topological perturbation analysis (TPA) is proposed to reveal the critical target in the blood coagulation system. The proposed topological tools can be directly applied to systems biology, omics sciences, topological materials, and machine learning study of molecular and materials sciences.

16.
Diabetes Metab Res Rev ; : e3616, 2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36657181

RESUMO

AIMS: To develop and validate a risk prediction model for Chinese patients with type 2 diabetes with the recurrence of diabetes foot ulcers (DFU) based on systematic review and meta-analysis. METHODS: A prospective analysis was performed with 1333 participants and followed up for 60 months. Three models were analyzed using derived cohort. The risk factors were screened by meta-analysis and logistic regression, and the missing variables were interpolated by multiple imputation. The internal validation was performed by the bootstrap procedure, validation cohort was applied to the external validation. The performance of model was evaluated the area under the discrimination receiver Operating Characteristic Curve (ROC). The calibration and discrimination methods were used for the validation cohort. The variables were selected according to their clinical and statistical importance to construct the nomograms. RESULTS: Three models were developed and validated. Model 1 included seven social and clinical indicators like Sex, DM duration, Previous DFU, Location of ulcer, Smoker, History of amputation and Foot deformity. Model 2 included four more indicators besides those in Model 1, which were Statin agents used, Antiplatelet agents used, SBP and BMI. Model 3 added further laboratory indicators to Model 2 such as LDL-C, HbA1C, FIB and BUN. In the derivation cohort, 20.1% (206/1027) participants with DFU were recurred as compared to the validation cohort, which was 38.2% (117/306). The AUC in the derivation cohort for Models1-3 were 0.781 (0.744-0.817), 0.843 (0.813-0.873) and 0.899 (0.876-0.922) respectively. The Youden index for Model 1-3 were 0.430, 0.559 and 0.653 respectively. Model 3 showed the highest sensitivity and specificity. All models performed well for both discrimination and calibration. CONCLUSION: Model 1-2 were non-invasive, which indicated their role in general screening for patients at the high-risk of recurrence DFU. However, Model 3 offered a more specific screening due to its best performance in predicting the risk of DFU recurrence amongst three models. This article is protected by copyright. All rights reserved.

17.
Hear Res ; 429: 108696, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36669260

RESUMO

Multiple aspects of brain development are influenced by early sensory loss such as deafness. Despite growing evidence of changes in attentional functions for prelingual profoundly deaf, the brain mechanisms underlying these attentional changes remain unclear. This study investigated the relationships between differential attention and the resting-state brain network difference in deaf individuals from the perspective of brain network connectivity. We recruited 36 deaf individuals and 34 healthy controls (HC). We recorded each participant's resting-state electroencephalogram (EEG) and the event-related potential (ERP) data from the Attention Network Test (ANT). The coherence (COH) method and graph theory were used to build brain networks and analyze network connectivity. First, the ERPs of analysis in task states were investigated. Then, we correlated the topological properties of the network functional connectivity with the ERPs. The results revealed a significant correlation between frontal-occipital connection in the resting state and the amplitude of alert N1 amplitude in the alpha band. Specifically, clustering coefficients and global and local efficiency correlate negatively with alert N1 amplitude, whereas the characteristic path length positively correlates with alert N1 amplitude. In addition, deaf individuals exhibited weaker frontal-occipital connections compared to the HC group. In executive control, the deaf group had longer reaction times and larger P3 amplitudes. However, the orienting function did not significantly differ from the HC group. Finally, the alert N1 amplitude in the ANT task for deaf individuals was predicted using a multiple linear regression model based on resting-state EEG network properties. Our results suggest that deafness affects the performance of alerting and executive control while orienting functions develop similarly to hearing individuals. Furthermore, weakened frontal-occipital connections in the deaf brain are a fundamental cause of altered alerting functions in the deaf. These results reveal important effects of brain networks on attentional function from the perspective of brain connections and provide potential physiological biomarkers to predicting attention.

18.
Acupunct Med ; : 9645284221146201, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36651215
19.
Small ; : e2207073, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36642808

RESUMO

Elastomers generally possess low Young's modulus and high failure strain, which are widely used in soft robots and intelligent actuators. However, elastomers generally lack diverse functionalities, such as stimulated shape morphing, and a general strategy to implement these functionalities into elastomers is still challenging. Here, a microfluidic 3D droplet printing platform is developed to design composite elastomers architected with arrays of functional droplets. Functional droplets with controlled size, composition, position, and pattern are designed and implemented in the composite elastomers, imparting functional performances to the systems. The composited elastomers are sensitive to stimuli, such as solvent, temperature, and light, and are able to demonstrate multishape (bow- and S-shaped), multimode (gradual and sudden), and multistep (one- and two-step) deformations. Based on the unique properties of droplet-embedded composite elastomers, a variety of stimuli-responsive systems are developed, including designable numbers, biomimetic flowers, and soft robots, and a series of functional performances are achieved, presenting a facile platform to impart diverse functionalities into composite elastomers by microfluidic 3D droplet printing.

20.
Polymers (Basel) ; 15(1)2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36616591

RESUMO

Epoxy (EP) was copolymerized with polyamic acid (PAA, precursor of polyimide (PI)) with termanil monomers of (1) 4,4'-Oxydianiline (ODA) and (2) pyromellitic dianhydride (PMDA) individually to form (PI-O-EP) and (PI-P-EP) copolymers. The FTIR spectrum of PI-O-EP copolymerization intermediates shows that some amide-EP linkages were formed at low temperature and were broken at higher temperature; in additoin, the released amide was available for subsequent imidization to form PI. The curing and imidization of the amide groups on PAA were determined by reaction temperature (kinetic vs. thermodynamic control). In PI-P-EP, the released amide group was very short-lived (fast imidization) and was not observed on FTIR spectra. Formation and breakage of the amide-EP linkages is the key step for EP homopolymerization and formation of the interpenetration network. PI contributed in improving thermal durability and mechanical strength without compromising EP's adhesion strength. Microphase separations were minimal at PI content less than 10 wt%. The copolymerization reaction in this study followed the "kinetic vs. thermodynamic control" principle. The copolymer has high potential for application in the field of higher-temperature anticorrosion.

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