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1.
Ultrason Sonochem ; 104: 106817, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38394824

ABSTRACT

A comprehensive investigation aimed to access the impacts of ultrasonic, microwave, and ultrasonic-microwave synergistic modification on the physicochemical properties, microstructure, and functional properties of corn bran insoluble dietary fiber (CBIDF). Our findings revealed that CBIDF presented a porous structure with loose folds, and the particle size and relative crystallinity were slightly decreased after modification. The CBIDF, which was modified by ultrasound-microwave synergistic treatment, exhibited remarkable benefits in terms of its adsorption capacity, and cholate adsorption capacity. Furthermore, the modification improved the in vitro hypoglycemic activity of the CBIDF by enhancing glucose absorption, retarding the starch hydrolysis, and facilitating the diffusion of glucose solution. The findings from the in vitro probiotic activity indicate that ultrasound-microwave synergistic modification also enhances the growth-promoting ability and adsorbability of Lactobacillus acidophilus and Bifidobacterium longum. Additionally, the level of soluble dietary fiber was found to be positively correlated with CBIDF adsorbability, while the crystallinity of CBIDF showed a negative correlation with α-glucosidase and α-amylase inhibition activity, as well as water-holding capacity, and oil-holding capacity.


Subject(s)
Microwaves , Zea mays , Ultrasonics , Dietary Fiber , Glucose/chemistry
2.
Mol Pharm ; 21(2): 467-480, 2024 Feb 05.
Article in English | MEDLINE | ID: mdl-38266250

ABSTRACT

Photothermal therapy (PTT) is an effective cancer treatment method. Due to its easy focusing and tunability of the irradiation light, direct and accurate local treatment can be performed in a noninvasive manner by PTT. This treatment strategy requires the use of photothermal agents to convert light energy into heat energy, thereby achieving local heating and triggering biochemical processes to kill tumor cells. As a key factor in PTT, the photothermal conversion ability of photothermal agents directly determines the efficacy of PTT. In addition, photothermal agents generally have photothermal imaging (PTI) and photoacoustic imaging (PAI) functions, which can not only guide the optimization of irradiation conditions but also achieve the integration of disease diagnosis. If the photothermal agents have function of fluorescence imaging (FLI) or fluorescence enhancement, they can not only further improve the accuracy in disease diagnosis but also accurately determine the tumor location through multimodal imaging for corresponding treatment. In this paper, we summarize recent advances in photothermal agents with FLI or fluorescence enhancement functions for PTT and tumor diagnosis. According to the different recognition sites, the application of specific targeting photothermal agents is introduced. Finally, limitations and challenges of photothermal agents with fluorescence imaging/enhancement in the field of PTT and tumor diagnosis are prospected.


Subject(s)
Nanoparticles , Neoplasms , Humans , Phototherapy/methods , Photothermal Therapy , Cell Line, Tumor , Neoplasms/diagnostic imaging , Neoplasms/therapy , Theranostic Nanomedicine/methods , Optical Imaging
3.
Folia Neuropathol ; 60(3): 346-354, 2022.
Article in English | MEDLINE | ID: mdl-36382488

ABSTRACT

INTRODUCTION: The paper aimed to explore the mechanism of miR-137 in modulating glioma. MATERIAL AND METHODS: qRT-PCR detected miR-137 and E2F7 mRNA expression in cells. The protein expression of E2F7 was measured using Western blot assay. Cell proliferation, scratch healing, transwell and programmed cell death assays were conducted to examine the influences of the genes on the biological function of glioma cells. The dual-luciferase assay verified the interaction between miR-137 and E2F7. RESULTS: MiR-137 was lowly expressed in glioma cells, and E2F7 was highly expressed. MiR-137 suppressed progression and promoted programmed cell death of glioma cells. MiR-137 could target and negatively regulate E2F7 expression to further accelerate programmed cell death of glioma cells. CONCLUSIONS: It was found that miR-137 could target E2F7 to restrain cell progression and accelerate programmed cell death of glioma cells, which is helpful to search for new molecular therapeutic targets for glioma.


Subject(s)
Glioma , MicroRNAs , Humans , Gene Expression Regulation, Neoplastic/genetics , Cell Movement , Cell Line, Tumor , MicroRNAs/genetics , MicroRNAs/metabolism , Glioma/genetics , Cell Proliferation/genetics , E2F7 Transcription Factor/genetics , E2F7 Transcription Factor/metabolism
4.
Brain Behav ; 12(12): e2632, 2022 12.
Article in English | MEDLINE | ID: mdl-36303447

ABSTRACT

OBJECTIVE: We attempted to investigate influence of microRNA-433-3p on malignant progression of glioma and identify its molecular mechanism, thus laying groundwork for glioma management. METHODS: Expression data along with clinical data of glioma were accessed from the TCGA database for differential and survival analyses to look for the target differentially expressed genes. Quantitative reverse transcriptase PCR (qRT-PCR) and western blot were utilized to assess NR5A2 mRNA and protein expression in different glioma cell lines, respectively. MTT, Transwell assay, and flow cytometry were carried out to assay the impact of NR5A2 on behaviors of glioma cells in vitro. Bioinformatics analysis was used to identify the upstream microRNA of NR5A2 in glioma, while dual-luciferase and western blot assays were used to detect binding of microRNA and NR5A2. Chemosensitivity of glioma cells was evaluated by cisplatin cytotoxicity test. RESULTS: NR5A2 was upregulated in both glioma tissues and cell lines. Dual-luciferase assay result showed binding site of microRNA-433-3p on NR5A2 mRNA 3'UTR, and microRNA-433-3p reduced NR5A2 expression. Cell assays revealed that silencing NR5A2 could hamper proliferation, invasion, and migration and enhance chemosensitivity to cisplatin while promoting glioma cell apoptosis and blocking glioma cells in G0/G1 phase. Rescue experiments also indicated that microRNA-433-3p suppressed glioma malignant progression via inhibiting NR5A2. CONCLUSION: MicroRNA-433-3p which is significantly poorly expressed in glioma targets NR5A2 to suppress glioma malignant progression and enhance chemosensitivity to cisplatin.


Subject(s)
Glioma , MicroRNAs , Humans , Cisplatin/pharmacology , Gene Expression Regulation, Neoplastic , Cell Line, Tumor , Glioma/drug therapy , Glioma/genetics , MicroRNAs/metabolism , Apoptosis , RNA, Messenger , Cell Proliferation , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/metabolism
5.
Front Nutr ; 9: 951821, 2022.
Article in English | MEDLINE | ID: mdl-35911126

ABSTRACT

This study was designed for determining the effect of particle size on the functional properties of corn bran insoluble dietary fiber (IDF). Results showed that some physicochemical properties were improved with the decrease in particle size. The structure of the IDF was observed by the scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The surface was found wrinkled and sparse, the particle size was smaller, the crystallinity of IDF had increased slightly, and more -OH and C-O groups were exposed. Moreover, the corn bran IDF with a smaller particle size had a better hypoglycemic effect in vitro, and the inhibitory activity of α-glucosidase and α-amylase were also increased significantly with the decrease in particle size (p < 0.05). When the IDF was 300 mesh, the inhibitory rate of α-glucosidase was 61.34 ± 1.12%, and the inhibitory rate of α-amylase was 17.58 ± 0.33%. It had increased by 25.54 and 106.83%, respectively compared to the control treatment (CK) group. In addition, correlation analysis found that the particle size was highly negatively correlated with some functional properties of IDF (p < 0.05), and the content of cellulose was positively correlated with the functional properties of IDF except WHC (p < 0.05). To sum up, reducing particle size was suitable for the development of high value-added IDF products. This study also revealed the potential value of corn bran IDF and provided a new idea for the diversified application of IDF.

6.
J AOAC Int ; 105(6): 1741-1754, 2022 Oct 26.
Article in English | MEDLINE | ID: mdl-35876857

ABSTRACT

BACKGROUND: Rumex japonicus Houtt (R. japonicus) is used mainly to treat various skin diseases in Southeast Asia. However, there are few studies on its quality evaluation methods and antifungal activity. OBJECTIVE: To establish the quality control criteria for the effective parts from R. japonicus against psoriasis. METHODS: High-performance liquid chromatography (HPLC) was established for its fingerprint, and the similarity evaluation, cluster analysis (CA) and principal component analysis (PCA) were used to reveal the differences of those fingerprints among the tested R. japonicus. Network pharmacology analyzed the relationship between the components and psoriasis, revealing the potential targets of R. japonicus. Oxford cup anti-C. albicans experiment was used to verify the antifungal activity of R. japonicus. RESULTS: HPLC was developed for the R. japonicus fingerprint by optimizing for 10 batches of quinquennial R. japonicus from different habitats; the 18 common peaks were identified with 10 characteristic peaks such as rutin, quercetin, aloe-emodin, nepodin, emodin, musizin-8-O-ß-D-glucoside, chrysophanol, emodin-8-O-ß-D-glucopyranoside, chrysophanol-8-O-ß-D-glucopyranoside, and aloin, respectively. The network pharmacology-based analysis showed a high correlation between R. japonicus and psoriasis, revealing the potential targets of R. japonicus. The oxford cup anti-Candida albicans experiment displayed a significant activity response to emodin-8-O-ß-D-glucopyranoside and the ethyl acetate fraction of R. japonicus acidic aqueous extract. CONCLUSIONS: A new and optimized HPLC method was created, and the research provides an experimental basis for the development of effective drugs related to C. albicans. HIGHLIGHTS: The fingerprint of R. japonicus was organically combined with network pharmacology to further clarify its criteria for quality control.


Subject(s)
Drugs, Chinese Herbal , Emodin , Psoriasis , Rumex , Humans , Rumex/chemistry , Chromatography, High Pressure Liquid , Antifungal Agents/pharmacology , Quercetin , Network Pharmacology , Glucosides , Rutin , Drugs, Chinese Herbal/pharmacology
7.
Food Chem ; 380: 132210, 2022 Jun 30.
Article in English | MEDLINE | ID: mdl-35093648

ABSTRACT

A novel mixture of glycopeptides was prepared from corn glutelin and glucosamine (GlcN). The functional properties and antioxidative activities of this mixture were investigated. Corn glutelin was limited hydrolyzed by Alcalase, and then its hydrolysates were glycosylated with GlcN by transglutaminase (TGase) to modify its main and side chain, respectively. Under the optimized conditions, the content of GlcN conjugated to peptides was 81.98 ± 1.98 mg/g glutelin peptides. According to electrospray ionization mass spectrometry (ESI-MS) analysis, there are two types of glycopeptides in the mixture, TGase and non-enzymatic glycated counterparts. Compared with original glutelin, the glycosylated glutelin hydrolysates exhibited better solubility in the pH range of 2-11 and other functional properties except foaming stability. Meanwhile, it is more easily digested by pepsin and trypsin, and possessed excellent antioxidative activities. It also exhibited cytoprotective effects and intracellular ROS scavenging activities in LO2 cells subjected to oxidative stress by oxidation with ethanol solution.


Subject(s)
Antioxidants , Glutens , Glucosamine , Hydrolysis , Protein Hydrolysates , Transglutaminases
8.
Tumori ; 108(4): 338-346, 2022 Aug.
Article in English | MEDLINE | ID: mdl-34121515

ABSTRACT

Several studies have shown the ability of transcription factor 12 (TCF12) to promote tumor malignant progression, but its function in glioma cells has not been fully elucidated. In this study, we analyzed the data from TCGA by bioinformatics and found that in glioma tissue, TCF12 was conspicuously highly expressed while miR-218-5p was significantly low-expressed. The downregulation of miR-218-5p was correlated with adverse prognosis in patients with glioma. miR-218-5p was found to be negatively associated with TCF12 by Pearson correlation analysis, and dual luciferase assay was employed to verify that miR-218-5p and TCF12 had a targeting relationship. qRT-PCR and Western blot assays were used to verify that the expression of TCF12 was regulated by its upstream regulator miR-218-5p. Moreover, cell experiments validated that overexpressed TCF12 could promote the proliferation, migration, and invasion of glioma cells and inhibit their apoptosis, whereas overexpressing miR-218-5p at the same time could reverse this phenomenon. Our study demonstrates the regulatory mechanism of the miR-218-5p/TCF12 axis in gliomas, which lays a foundation for searching for new therapeutic approaches for glioma.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors , Glioma , MicroRNAs , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic , Glioma/genetics , Glioma/pathology , Humans , MicroRNAs/genetics , Neoplasm Invasiveness/genetics , Neoplasm Invasiveness/pathology
9.
Brain Res ; 1767: 147563, 2021 09 15.
Article in English | MEDLINE | ID: mdl-34147470

ABSTRACT

OBJECTIVE: Glioma is a common primary malignant brain tumor characterized by high mortality and poor prognosis. The purpose of this study is to explore the molecular mechanism underlying glioma, aiming to provide a new target for the treatment of glioma to improve the prognosis of patients. METHODS: The differentially expressed genes and regulatory axis affecting the prognosis of glioma were identified with bioinformatics analysis, and the expression of miR-433-3p and SMC4 mRNA was detected with qRT-PCR. The expression of SMC4 and epithelial-mesenchymal transition (EMT)-associated proteins were detected with western blot. The targeting relationship between miR-433-3p and SMC4 was verified with dual-luciferase reporter gene assay. The proliferative ability of glioma cells was detected with CCK-8 assay, while the migration and invasion of glioma cells were detected with Transwell assay. RESULTS: We found that the expression of SMC4 was significantly up-regulated in glioma, showing that SMC4 was an unfavorable factor for prognosis and could promote the progression of cancer cells. Its upstream regulator miR-433-3p was significantly down-regulated in glioma, which inhibited the development of cancer cells. Moreover, miR-433-3p could target to inhibit the expression of SMC4. Rescue assay showed that miR-433-3p could affect the development of glioma by regulating the expression of SMC4. CONCLUSION: Our data demonstrate for the first time that SMC4 is a direct target of miR-433-3p, and elucidate the molecular mechanism by which miR-433-3p inhibits the malignant progression of glioma by targeting and down-regulating the expression of SMC4.


Subject(s)
Adenosine Triphosphatases/metabolism , Chromosomal Proteins, Non-Histone/metabolism , Glioma/genetics , MicroRNAs/genetics , Adenosine Triphosphatases/genetics , Brain Neoplasms/metabolism , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Chromosomal Proteins, Non-Histone/genetics , Databases, Genetic , Epithelial-Mesenchymal Transition/genetics , Gene Expression/genetics , Gene Expression Regulation, Neoplastic/genetics , Glioma/metabolism , Humans , MicroRNAs/metabolism , Neoplasm Invasiveness/genetics , RNA, Circular/genetics , Transcriptome/genetics
10.
Genes Genomics ; 43(10): 1157-1165, 2021 10.
Article in English | MEDLINE | ID: mdl-34160745

ABSTRACT

BACKGROUND: Gliomas are common malignant tumors in the nervous system, known for poor prognosis and low survival rate. OBJECTIVE: This study aims to explore functions of miR-137 in glioma progression and identify messenger RNAs (mRNA) regulated by miR-137, which provides new ideas for further exploration of glioma therapeutic targets. METHODS: Gene expression data were downloaded from the Cancer Genome Atlas database, and abnormally expressed miRNAs and mRNAs in glioma were analyzed. The expression of genes in 20 pairs of clinical tissue samples and glioma cell lines were detected through qRT-PCR, and the expression of proteins was detected through Western blot. Changes in cell proliferative level after transfection were detected via CCK8 assay, and changes in cell migratory and invasive abilities were detected by Transwell assay. Besides, dual-luciferase reporter assay was employed to testify binding relationship between two genes. RESULTS: Our study found that miR-137 was significantly and lowly expressed in glioma tissue and cell lines, and the prognoses of glioma patients with highly expressed miR-137 were more optimistic. Overexpressed miR-137 could remarkably inhibit proliferative, invasive and migratory abilities of glioma cells U87, while transfection of miR-137 inhibitor presented an opposite effect. Additionally, EZH2 was a direct target of miR-137 and overexpressed EZH2 effectively reversed the effect of miR-137 on glioma proliferation and migration. CONCLUSIONS: Our study found that miR-137 could suppress the proliferation, invasion and migration of glioma cells through regulating the expression of EZH2. So far, we have found a novel regulatory pair that influences glioma progression, providing a basis for further development of new therapeutic strategies.


Subject(s)
Cell Movement , Cell Proliferation , Enhancer of Zeste Homolog 2 Protein/biosynthesis , MicroRNAs/metabolism , Neoplasm Proteins/biosynthesis , RNA, Neoplasm/metabolism , Adult , Aged , Cell Line, Tumor , Enhancer of Zeste Homolog 2 Protein/genetics , Female , Humans , Male , MicroRNAs/genetics , Middle Aged , Neoplasm Invasiveness , Neoplasm Proteins/genetics , RNA, Neoplasm/genetics
11.
J Sci Food Agric ; 101(2): 433-440, 2021 Jan 30.
Article in English | MEDLINE | ID: mdl-32648587

ABSTRACT

BACKGROUND: Dry heat processing remains the most promising and simple approach for achieving better gelling properties of spray-dried egg white powder (EWP). Water mobility and intermolecular interactions in gels derived from EWP were investigated after subjecting EWP to various dry heating times (0-21 days). RESULTS: The gel hardness and water-holding capacity significantly increased with an increase in dry heating time (P < 0.05), and both parameters were positively correlated with gel transparency. In contrast to the coarser structure of untreated EWP gel, the gel of EWP corresponding to 15 days of dry heating time had a fine-stranded and orderly network structure with smaller pores. An increase in the binding force between the gel and water was observed with an increase in dry heating time due to the formation of more 'protein-water' hydrogen bonds. Increasing the dry heating time resulted in an increase in the contribution of disulfide bonds, which in turn made a significant contribution to the rigidity of the EWP gels. By contrast, a decrease in the contribution of ionic bonds and hydrophobic interactions upon increasing the dry heating time promoted the formation of orderly networks. CONCLUSIONS: Overall, gel corresponding to EWP dry heating for 15 days had better gel properties, the highest transparency and water-holding capacity, as well as a fine-stranded and orderly network structure. These results provide more information on improvement of the gel properties of EWP through dry heat treatment. © 2020 Society of Chemical Industry.


Subject(s)
Cooking/methods , Egg White/chemistry , Animals , Chickens , Cooking/instrumentation , Eggs/analysis , Eggs/parasitology , Gels/chemistry , Hot Temperature , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Powders/chemistry , Solubility
12.
Cell Cycle ; 19(21): 2826-2835, 2020 11.
Article in English | MEDLINE | ID: mdl-33064966

ABSTRACT

This study aims to explore the molecular mechanism by which HAS2-AS1 acts as a ceRNA to promote the invasion and migration of glioma cells, which will provide a novel potential target for the targeted therapy of glioma. Gene expression profiles and corresponding clinical data were accessed from the TCGA_LGG and TCGA_GBM databases and then differential analysis was conducted using the "edgeR" package. miRDB, miRTarBase and TargetScan databases were employed to predict target genes and sequentially a ceRNA network was constructed. Quantitative real-time PCR was performed to detect gene expression in glioma cells. Transwell assay was operated to assess cell migratory and invasive abilities. Western blot was conducted to evaluate the protein expression. Dual-luciferase reporter assay and RNA immunoprecipitation experiment were performed to validate the targeting relationship between genes. HAS2-AS1 was markedly upregulated in glioma, and the overall survival time of patients with high HAS2-AS1 expression was significantly shorter than that of patients with low one. Silencing HAS2-AS1 inhibited the migration and invasion of glioma cells, while overexpressing HAS2-AS1 produced opposite results. miR-137 was validated as a direct target of and negatively regulated by HAS2-AS1. Further exploration of the downstream target gene indicated that EZH2 competed with HAS2-AS1 to interact with miR-137. Suppressing miR-137 or up-regulating EZH2 reversed the impact of HAS2-AS1 knockdown on glioma cell invasion and migration. HAS2-AS1 regulates EZH2 by sponging miR-137 for the migratory and invasive abilities of glioma cells, which provides a new idea for exploring metastasis mechanism of glioma.


Subject(s)
Cell Movement/genetics , Enhancer of Zeste Homolog 2 Protein/genetics , Hyaluronan Synthases/genetics , MicroRNAs/genetics , Neoplasm Invasiveness/genetics , Cell Line , Cell Line, Tumor , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic/genetics , Glioma/genetics , Glioma/pathology , Humans , Neoplasm Invasiveness/pathology , RNA, Long Noncoding/genetics
13.
Biosci Rep ; 40(8)2020 08 28.
Article in English | MEDLINE | ID: mdl-32776110

ABSTRACT

OBJECTIVE: The role of lncRNAs in tumor has been widely concerned. The present study took HAS2-AS1 (the antisense RNA 1 of HAS2) as a starting point to explore its expression in glioma and its role in the process of migration and invasion, providing a strong theoretical basis for mining potential therapeutic targets of glioma. METHODS: Clinical data of glioma were obtained from The Cancer Genome Atlas (TCGA) database and differentially expressed lncRNAs were analyzed by edgeR. The hTFtarget database was used to predict the upstream transcription factors of HAS2-AS1 and the JASPAR website was used to predict the binding sites of human upstream transcription factor 1 (USF1) and HAS2-AS1. qRT-PCR was used to detect the expressions of HAS2-AS1 and USF1 in glioma tissues and cell lines. The effects of silencing HAS2-AS1 on the migration and invasion of cancer cells were verified by wound healing and Transwell invasion assays. The chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays were applied to demonstrate the binding of USF1 and HAS2-AS1 promoter region. Western blot was used to detect the expressions of epithelial-mesenchymal transition (EMT)-related proteins. RESULTS: HAS2-AS1 was highly expressed in glioma tissues and cells, and was significantly associated with poor prognosis. Silencing HAS2-AS1 expression inhibited glioma cell migration, invasion and EMT. USF1 was highly expressed in glioma and positively correlated with HAS2-AS1. The transcription of HAS2-AS1 was activated by USF1 via binding to HAS2-AS1 promoter region, consequently potentiating the invasion and migration abilities of glioma cells. CONCLUSION: These results suggested that the transcription factor USF1 induced up-regulation of lncRNA HAS2-AS1 and promoted glioma cell invasion and migration.


Subject(s)
Brain Neoplasms/metabolism , Cell Movement , Glioma/metabolism , RNA, Long Noncoding/metabolism , Upstream Stimulatory Factors/metabolism , Binding Sites , Brain Neoplasms/genetics , Brain Neoplasms/pathology , Case-Control Studies , Cell Line, Tumor , Databases, Genetic , Epithelial-Mesenchymal Transition , Gene Expression Regulation, Neoplastic , Glioma/genetics , Glioma/pathology , Humans , Neoplasm Invasiveness , Promoter Regions, Genetic , RNA, Long Noncoding/genetics , Signal Transduction , Upstream Stimulatory Factors/genetics
14.
Sci Adv ; 4(11): eaau5849, 2018 11.
Article in English | MEDLINE | ID: mdl-30406207

ABSTRACT

With accelerating trends in miniaturization of semiconductor devices, techniques for energy harvesting become increasingly important, especially in wearable technologies and sensors for the internet of things. Although thermoelectric systems have many attractive attributes in this context, maintaining large temperature differences across the device terminals and achieving low-thermal impedance interfaces to the surrounding environment become increasingly difficult to achieve as the characteristic dimensions decrease. Here, we propose and demonstrate an architectural solution to this problem, where thin-film active materials integrate into compliant, open three-dimensional (3D) forms. This approach not only enables efficient thermal impedance matching but also multiplies the heat flow through the harvester, thereby increasing the efficiencies for power conversion. Interconnected arrays of 3D thermoelectric coils built using microscale ribbons of monocrystalline silicon as the active material demonstrate these concepts. Quantitative measurements and simulations establish the basic operating principles and the key design features. The results suggest a scalable strategy for deploying hard thermoelectric thin-film materials in harvesters that can integrate effectively with soft materials systems, including those of the human body.

15.
ACS Nano ; 12(9): 9240-9252, 2018 09 25.
Article in English | MEDLINE | ID: mdl-30192507

ABSTRACT

Memristors based on 2D layered materials could provide biorealistic ionic interactions and potentially enable construction of energy-efficient artificial neural networks capable of faithfully emulating neuronal interconnections in human brains. To build reliable 2D-material-based memristors suitable for constructing working neural networks, the memristive switching mechanisms in such memristors need to be systematically analyzed. Here, we present a study on the switching characteristics of the few-layer MoS2 memristors made by mechanical printing. First, two types of dc-programmed switching characteristics, termed rectification-mediated and conductance-mediated behaviors, are observed among different MoS2 memristors, which are attributed to the modulation of MoS2/metal Schottky barriers and redistribution of vacancies, respectively. We also found that an as-fabricated MoS2 memristor initially exhibits an analog pulse-programmed switching behavior, but it can be converted to a quasi-binary memristor with an abrupt switching behavior through an electrical stress process. Such a transition of switching characteristics is attributed to field-induced agglomeration of vacancies at MoS2/metal interfaces. The additional Kelvin probe force microscopy, Auger electron spectroscopy analysis, and electronic characterization results support this hypothesis. Finally, we fabricated a testing device consisting of two adjacent MoS2 memristors and demonstrated that these two memristors can be ionically coupled to each other. This device interconnection scheme could be exploited to build neural networks for emulating ionic interactions among neurons. This work advances the device physics for understanding the memristive properties of 2D-material-based memristors and serves as a critical foundation for building biorealistic neuromorphic computing systems based on such memristors.


Subject(s)
Disulfides/metabolism , Molybdenum/metabolism , Neural Networks, Computer , Synapses/metabolism , Brain/metabolism , Disulfides/chemistry , Electronics , Humans , Molybdenum/chemistry , Particle Size , Printing , Surface Properties
16.
Food Chem ; 246: 18-25, 2018 Apr 25.
Article in English | MEDLINE | ID: mdl-29291838

ABSTRACT

Egg white powder is widely used as a food ingredient instead of fresh eggs. Dry heat treatment plays an essential role in the processing of egg white powder to obtain its excellent functionalities. In this study, the effect of dry heat treatment on egg white protein (EWP) was evaluated by determining its physicochemical properties and in vitro pepsin digestion. The results indicated that dry heat treatment reduced EWP thermal stability and tryptophan fluorescence and increased its surface hydrophobicity. SDS-PAGE revealed that abundant soluble aggregates formed during dry heating, and these aggregates could be digested by pepsin. The digestibility of dry-heated EWP was better than for untreated EWP, and the essential amino acid and low-molecular-weight peptide (Mw < 1 kDa) contents increased with increasing dry heating time. In vitro digests of EWP that were dry heat treated for 9-15 days exhibited excellent antioxidant properties.


Subject(s)
Antioxidants/pharmacology , Egg Proteins/chemistry , Egg Proteins/pharmacology , Amino Acids/analysis , Antioxidants/chemistry , Digestion , Egg Proteins/metabolism , Electrophoresis, Polyacrylamide Gel , Food Handling , Hot Temperature , Hydrophobic and Hydrophilic Interactions , Molecular Weight , Pepsin A/chemistry , Pepsin A/metabolism , Protein Stability , Spectrometry, Fluorescence , Tryptophan/chemistry
17.
Nat Mater ; 17(3): 268-276, 2018 03.
Article in English | MEDLINE | ID: mdl-29379201

ABSTRACT

Three-dimensional (3D) structures capable of reversible transformations in their geometrical layouts have important applications across a broad range of areas. Most morphable 3D systems rely on concepts inspired by origami/kirigami or techniques of 3D printing with responsive materials. The development of schemes that can simultaneously apply across a wide range of size scales and with classes of advanced materials found in state-of-the-art microsystem technologies remains challenging. Here, we introduce a set of concepts for morphable 3D mesostructures in diverse materials and fully formed planar devices spanning length scales from micrometres to millimetres. The approaches rely on elastomer platforms deformed in different time sequences to elastically alter the 3D geometries of supported mesostructures via nonlinear mechanical buckling. Over 20 examples have been experimentally and theoretically investigated, including mesostructures that can be reshaped between different geometries as well as those that can morph into three or more distinct states. An adaptive radiofrequency circuit and a concealable electromagnetic device provide examples of functionally reconfigurable microelectronic devices.

18.
Adv Funct Mater ; 27(1)2017 Jan 05.
Article in English | MEDLINE | ID: mdl-28970775

ABSTRACT

Approaches capable of creating three-dimensional (3D) mesostructures in advanced materials (device-grade semiconductors, electroactive polymers etc.) are of increasing interest in modern materials research. A versatile set of approaches exploits transformation of planar precursors into 3D architectures through the action of compressive forces associated with release of prestrain in a supporting elastomer substrate. Although a diverse set of 3D structures can be realized in nearly any class of material in this way, all previously reported demonstrations lack the ability to vary the degree of compression imparted to different regions of the 2D precursor, thus constraining the diversity of 3D geometries. This paper presents a set of ideas in materials and mechanics in which elastomeric substrates with engineered distributions of thickness yield desired strain distributions for targeted control over resultant 3D mesostructures geometries. This approach is compatible with a broad range of advanced functional materials from device-grade semiconductors to commercially available thin films, over length scales from tens of microns to several millimeters. A wide range of 3D structures can be produced in this way, some of which have direct relevance to applications in tunable optics and stretchable electronics.

19.
Small ; 13(24)2017 06.
Article in English | MEDLINE | ID: mdl-28489315

ABSTRACT

Formation of 3D mesostructures in advanced functional materials is of growing interest due to the widespread envisioned applications of devices that exploit 3D architectures. Mechanically guided assembly based on compressive buckling of 2D precursors represents a promising method, with applicability to a diverse set of geometries and materials, including inorganic semiconductors, metals, polymers, and their heterogeneous combinations. This paper introduces ideas that extend the levels of control and the range of 3D layouts that are achievable in this manner. Here, thin, patterned layers with well-defined residual stresses influence the process of 2D to 3D geometric transformation. Systematic studies through combined analytical modeling, numerical simulations, and experimental observations demonstrate the effectiveness of the proposed strategy through ≈20 example cases with a broad range of complex 3D topologies. The results elucidate the ability of these stressed layers to alter the energy landscape associated with the transformation process and, specifically, the energy barriers that separate different stable modes in the final 3D configurations. A demonstration in a mechanically tunable microbalance illustrates the utility of these ideas in a simple structure designed for mass measurement.


Subject(s)
Nanostructures/chemistry , Polymers/chemistry , Printing, Three-Dimensional
20.
Proc Natl Acad Sci U S A ; 112(38): 11757-64, 2015 Sep 22.
Article in English | MEDLINE | ID: mdl-26372959

ABSTRACT

Assembly of 3D micro/nanostructures in advanced functional materials has important implications across broad areas of technology. Existing approaches are compatible, however, only with narrow classes of materials and/or 3D geometries. This paper introduces ideas for a form of Kirigami that allows precise, mechanically driven assembly of 3D mesostructures of diverse materials from 2D micro/nanomembranes with strategically designed geometries and patterns of cuts. Theoretical and experimental studies demonstrate applicability of the methods across length scales from macro to nano, in materials ranging from monocrystalline silicon to plastic, with levels of topographical complexity that significantly exceed those that can be achieved using other approaches. A broad set of examples includes 3D silicon mesostructures and hybrid nanomembrane-nanoribbon systems, including heterogeneous combinations with polymers and metals, with critical dimensions that range from 100 nm to 30 mm. A 3D mechanically tunable optical transmission window provides an application example of this Kirigami process, enabled by theoretically guided design.

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