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1.
Nat Commun ; 15(1): 4940, 2024 Jun 10.
Article En | MEDLINE | ID: mdl-38858370

Dielectric capacitors offer great potential for advanced electronics due to their high power densities, but their energy density still needs to be further improved. High-entropy strategy has emerged as an effective method for improving energy storage performance, however, discovering new high-entropy systems within a high-dimensional composition space is a daunting challenge for traditional trial-and-error experiments. Here, based on phase-field simulations and limited experimental data, we propose a generative learning approach to accelerate the discovery of high-entropy dielectrics in a practically infinite exploration space of over 1011 combinations. By encoding-decoding latent space regularities to facilitate data sampling and forward inference, we employ inverse design to screen out the most promising combinations via a ranking strategy. Through only 5 sets of targeted experiments, we successfully obtain a Bi(Mg0.5Ti0.5)O3-based high-entropy dielectric film with a significantly improved energy density of 156 J cm-3 at an electric field of 5104 kV cm-1, surpassing the pristine film by more than eight-fold. This work introduces an effective and innovative avenue for designing high-entropy dielectrics with drastically reduced experimental cycles, which could be also extended to expedite the design of other multicomponent material systems with desired properties.

2.
J Biomed Res ; : 1-10, 2024 Jan 25.
Article En | MEDLINE | ID: mdl-38807485

Core 1 synthase glycoprotein-N-acetylgalactosamine 3-ß-galactosyltransferase 1 (C1GALT1) is known to play a critical role in the development of gastric cancer, but few studies have elucidated associations between genetic variants in C1GALT1 and gastric cancer susceptibility. By using the genome-wide association study data from the database of Genotype and Phenotype (dbGAP), we evaluated these associations with a logistic regression model and identified that the rs35999583 in C1GALT1 was associated with gastric cancer risk (odd ratio, 0.83; 95% confidence interval [CI], 0.75-0.92; P = 3.95 × 10 -4]. C1GALT1 mRNA expression was significantly higher in gastric tumor tissues, and gastric cancer patients with higher C1GALT1 mRNA levels had the worse overall survival rates (hazards ratio, 1.33; 95% CI, 1.05-1.68; P log-rank = 1.90 × 10 -2). Furthermore, we found that C1GALT1 copy number variations differed in various immune cells and C1GALT1 mRNA expression was positively correlated with the infiltrating levels of CD4 + T cells and macrophages. These results highlight that genetic variants of C1GALT1 may play an important role in gastric cancer risk and provide a new insight for C1GALT1 to be a promising predictor of gastric cancer susceptibility and immune status.

3.
BMC Plant Biol ; 24(1): 217, 2024 Mar 26.
Article En | MEDLINE | ID: mdl-38532319

Catalpa bungei is a precious timber species distributed in North China where drought often occurs. To clarify adaptive responses of C. bungei to partial- and full- root-zone drought under the influence of nitrogen forms, a two-factor experiment was conducted in which well-watered (WW), partial root-zone drought in horizontal direction (H-PRD) and in vertical direction (V-PRD), and full root-zone drought (FRD) were combined with nitrate-nitrogen (NN) and ammonium-nitrogen (AN) treatments. C. bungei responded to FRD by sharply closing stomata, decreasing gas exchange rate and increasing leaf instantaneous water use efficiency (WUEi). Under FRD condition, the growth of seedlings was severely inhibited and the effect of N forms was covered up by the drastic drought effect. In comparison, stomata conductance and gas exchanges were moderately inhibited by PRDs. WUEi in V-PRD treatment was superior to H-PRD due to the active stomata regulation resulting from a higher ABA level and active transcription of genes in abscisic acid (ABA) signaling pathway under V-PRD. Under both PRDs and FRD, nitrate benefited antioxidant defense, stomata regulation and leaf WUEi. Under V-PRD, WUEi in nitrate treatment was superior to that in ammonium treatment due to active stomata regulation by signaling network of nitric oxide (NO), Ca2+ and ABA. Under FRD, WUEi was higher in nitrate treatment due to the favoring photosynthetic efficiency resulting from active NO signal and antioxidant defense. The interactive effect of water and N forms was significant on wood xylem development. Superoxide dismutase (SOD) and catalase (CAT) largely contributes to stress tolerance and xylem development.


Nitrates , Nitrogen , Nitrogen/metabolism , Droughts , Antioxidants , Water/metabolism
4.
Nat Nanotechnol ; 19(5): 588-603, 2024 May.
Article En | MEDLINE | ID: mdl-38172431

Owing to their excellent discharged energy density over a broad temperature range, polymer nanocomposites offer immense potential as dielectric materials in advanced electrical and electronic systems, such as intelligent electric vehicles, smart grids and renewable energy generation. In recent years, various nanoscale approaches have been developed to induce appreciable enhancement in discharged energy density. In this Review, we discuss the state-of-the-art polymer nanocomposites with improved energy density from three key aspects: dipole activity, breakdown resistance and heat tolerance. We also describe the physical properties of polymer nanocomposite interfaces, showing how the electrical, mechanical and thermal characteristics impact energy storage performances and how they are interrelated. Further, we discuss multi-level nanotechnologies including monomer design, crosslinking, polymer blending, nanofiller incorporation and multilayer fabrication. We conclude by presenting the current challenges and future opportunities in this field.

5.
Nat Commun ; 15(1): 348, 2024 Jan 08.
Article En | MEDLINE | ID: mdl-38191601

Topology created by quasi-continuous spatial variations of a local polarization direction represents an exotic state of matter, but field-driven manipulation has been hitherto limited to creation and destruction. Here we report that relatively small electric or mechanical fields can drive the non-volatile rotation of polar spirals in discretized microregions of the relaxor ferroelectric polymer poly(vinylidene fluoride-ran-trifluoroethylene). These polar spirals arise from the asymmetric Coulomb interaction between vertically aligned helical polymer chains, and can be rotated in-plane through various angles with robust retention. Given also that our manipulation of topological order can be detected via infrared absorption, our work suggests a new direction for the application of complex materials.

6.
J Cell Mol Med ; 28(1): e18019, 2024 01.
Article En | MEDLINE | ID: mdl-37994607

Hypoxia-inducible factor (HIF) pathway genes influence tumorigenesis and immune status. However, the associations between genetic variants in hypoxia-related genes and colorectal cancer risk and the immune status of hypoxia-associated genes in colorectal cancer have not been systematically characterized. The associations between genetic variants and colorectal cancer risk were evaluated in Chinese, Japanese and European populations using logistic regression analysis. The relationships between target genes and tumour immune infiltration were predicted by Tumour Immune Estimation Resource (TIMER). We found that rs34533650 in EPAS1 was associated with colorectal cancer risk (OR = 1.43, 95% CI = 1.20-1.70, P(FDR) = 8.35 × 10-4 ), and this finding was validated in two independent populations (Japanese: OR = 1.07, 95% CI = 1.01-1.15, p = 3.38 × 10-2 ; European: OR = 1.11, 95% CI = 1.03-1.19, p = 6.04 × 10-3 ). EPAS1-associated genes were enriched in immune-related pathways. In addition, we found that EPAS1 copy number variation (CNV) was associated with the degree of infiltration of immune cells and observed correlations between EPAS1 expression and immune cell infiltration levels in colorectal cancer. These results highlight that genetic variants of hypoxia-related genes play roles in colorectal cancer risk and provide new insight that EPAS1 might be a promising predictor of colorectal cancer susceptibility and immune status.


Colorectal Neoplasms , DNA Copy Number Variations , Humans , Hypoxia/metabolism , Colorectal Neoplasms/pathology , Basic Helix-Loop-Helix Transcription Factors/metabolism
7.
J Biomed Res ; 37(6): 405-417, 2023 Nov 15.
Article En | MEDLINE | ID: mdl-37936490

Aberrant alternative polyadenylation (APA) events play an important role in cancers, but little is known about whether APA-related genetic variants contribute to the susceptibility to bladder cancer. Previous genome-wide association study performed APA quantitative trait loci (apaQTL) analyses in bladder cancer, and identified 17 955 single nucleotide polymorphisms (SNPs). We found that gene symbols of APA affected by apaQTL-associated SNPs were closely correlated with cancer signaling pathways, high mutational burden, and immune infiltration. Association analysis showed that apaQTL-associated SNPs rs34402449 C>A, rs2683524 C>T, and rs11540872 C>G were significantly associated with susceptibility to bladder cancer (rs34402449: OR = 1.355, 95% confidence interval [CI]: 1.159-1.583, P = 1.33 × 10 -4; rs2683524: OR = 1.378, 95% CI: 1.164-1.632, P = 2.03 × 10 -4; rs11540872: OR = 1.472, 95% CI: 1.193-1.815, P = 3.06 × 10 -4). Cumulative effect analysis showed that the number of risk genotypes and smoking status were significantly associated with an increased risk of bladder cancer ( P trend = 2.87 × 10 -12). We found that PRR13, being demonstrated the most significant effect on cell proliferation in bladder cancer cell lines, was more highly expressed in bladder cancer tissues than in adjacent normal tissues. Moreover, the rs2683524 T allele was correlated with shorter 3' untranslated regions of PRR13 and increased PRR13 expression levels. Collectively, our findings have provided informative apaQTL resources and insights into the regulatory mechanisms linking apaQTL-associated variants to bladder cancer risk.

8.
Natl Sci Rev ; 10(8): nwad177, 2023 Aug.
Article En | MEDLINE | ID: mdl-37485000

Flexible piezoelectric materials capable of withstanding large deformation play key roles in flexible electronics. Ferroelectric ceramics with a high piezoelectric coefficient are inherently brittle, whereas polar polymers exhibit a low piezoelectric coefficient. Here we report a highly stretchable/compressible piezoelectric composite composed of ferroelectric ceramic skeleton, elastomer matrix and relaxor ferroelectric-based hybrid at the ceramic/matrix interface as dielectric transition layers, exhibiting a giant piezoelectric coefficient of 250 picometers per volt, high electromechanical coupling factor keff of 65%, ultralow acoustic impedance of 3MRyl and high cyclic stability under 50% compression strain. The superior flexibility and piezoelectric properties are attributed to the electric polarization and mechanical load transfer paths formed by the ceramic skeleton, and dielectric mismatch mitigation between ceramic fillers and elastomer matrix by the dielectric transition layer. The synergistic fusion of ultrahigh piezoelectric properties and superior flexibility in these polymer composites is expected to drive emerging applications in flexible smart electronics.

9.
Cancer Res ; 83(13): 2142-2154, 2023 07 05.
Article En | MEDLINE | ID: mdl-37115853

Genetic variants in regions encoding 3' untranslated regions (UTR) of mRNA potentially alter miRNA binding affinity and N6-methyladenosine (m6A) levels to affect gene expression. A better understanding of the association of these variants with colorectal cancer susceptibility could facilitate development of cancer prevention and treatment approaches. Here, we analyzed miRNA expression profiles and integrated genetic analyses from 8,533 individuals to evaluate the effects of altered miRNA-binding sites on colorectal cancer risk. The single-nucleotide polymorphism rs11245997 in the BET1L 3'UTR was significantly associated with colorectal cancer risk. The rs11245997 A allele facilitated BET1L expression by disrupting miR-140-3p binding. It also reduced BET1L m6A modification, which upregulated BET1L expression levels through a mechanism mediated by the m6A methyltransferases (METTL14 and WTAP) and the m6A demethylase ALKBH5. Moreover, higher expression of BET1L was associated with advanced tumor stages and poor patient prognosis. Increased BET1L expression promoted growth of colorectal cancer cells in vitro and in vivo, which could be partially rescued with miR-140-3p overexpression. RNA sequencing and pathway analyses indicated that BET1L is associated with the steroid biosynthesis pathway through regulation of HSD17B7, CYP27B1, and COMT. These findings provide insights into the involvement of genetic variants of BET1L in the development and progression of colorectal cancer. SIGNIFICANCE: The integration of miRNA expression profiles and genetic variants identified rs11245997 as a colorectal cancer risk-related variant that reduces miR-140-3p binding and m6A modification, leading to BET1L upregulation to promote colorectal tumorigenesis.


Colorectal Neoplasms , MicroRNAs , Humans , Methyltransferases/metabolism , MicroRNAs/genetics , Carcinogenesis , Cell Transformation, Neoplastic , Cell Communication , Colorectal Neoplasms/genetics , Qc-SNARE Proteins
10.
Environ Sci Technol ; 57(7): 2864-2876, 2023 02 21.
Article En | MEDLINE | ID: mdl-36745568

Element contamination, including that from heavy metals, is associated with gastrointestinal tumorigenesis, but the effects and mechanisms of crucial element exposure associated with colorectal cancer remain unclear. We profiled 56 elements by ICP-MS and used logistic regression, LASSO, BKMR, and GAM to identify colorectal cancer-relevant elements. A series of biochemical experiments were performed to demonstrate the cytotoxicity and the mechanisms of malignant transformation after metal exposure. Using an elementomics approach, we first found that the metal thallium (Tl) was positively correlated with many toxic metals and was associated with a significantly increased risk of colorectal cancer. Acute exposure to Tl induced cytotoxicity and cell death by accelerating the generation of reactive oxygen species and DNA damage. Chronic exposure to Tl led to the inhibition of cell death and thereby induced the malignant transformation of normal colon cells and xenograft tumor formation in nude mice. Furthermore, we describe the first identification of a significant metal quantitative trait locus for the novel colorectal cancer susceptibility locus rs1511625 near ATP13A3. Mechanistically, Tl increased the level of aberrant N6-methyladenosine (m6A) modification of ATP13A3 via the METLL3/METTL14/ALKBH5-ATP13A3 axis to promote colorectal tumorigenesis. This study provides a basis for the development of public health strategies for reducing metal exposure among populations at high risk for colorectal cancer.


Colorectal Neoplasms , Metals, Heavy , Mice , Animals , Humans , Mice, Nude , Carcinogenesis , Metals, Heavy/toxicity , Thallium/toxicity , Colorectal Neoplasms/chemically induced , Adenosine Triphosphatases , Membrane Transport Proteins
11.
Adv Mater ; 35(16): e2209958, 2023 Apr.
Article En | MEDLINE | ID: mdl-36693075

High-dielectric-constant polymer composites have broad application prospects in flexible electronics and electrostatic energy storage capacitors. Substantial enhancement in dielectric constants (εr ) of polymer composites so far can only be obtained at a high loading of nanofillers, resulting in high dielectric loss and high elastic modulus of polymer composites. Addressing the polarization shielding and the consequent polarization discontinuity at polymer/filler interfaces has been a long-standing challenge to achieve flexible polymer composite with high εr . Herein, a polymer composite with interconnected BaTiO3 (BT) ceramic scaffold is proposed and demonstrated, which exhibits a high εr of ≈210 at a low BT volume fraction of ≈18 vol%, approaching the upper limit predicted by the parallel model. By incorporating relaxor Ba(Zrx Ti1-x )O3 phase in BT scaffold, dielectric temperature stability is further achieved with Δεr below ±10% within a broad temperature range (25-140 °C). Moreover, the dielectric performances remain stable under a compressive strain of up to 80%. This work provides a facile approach to construct large-scale polymer composites with robust dielectric performance against changes in thermal and mechanical conditions, which are promising for high-temperature applications in flexible electronics.

12.
Adv Sci (Weinh) ; 10(11): e2206344, 2023 04.
Article En | MEDLINE | ID: mdl-36721037

The peripheral T cell pool is maintained at dynamic homeostasis through fine-tuning of thymic output and self-renewal of naïve T cells. Lymphopenia or reduced lymphocyte number is implicated in autoimmune diseases, yet little is known about the homeostatic mechanisms. Here, it is reported that the replication protein A1 (RPA1) plays a critical role in T cell homeostasis. Utilizing T cell-specific Rpa1-deficient (Rpa1fl/fl Cd4-cre) mice, loss of Rpa1 results in lymphopenia through restraining peripheral T cell population and limiting TCR repertoire diversity. Moreover, Rpa1fl/fl Cd4-cre mice exhibit increased susceptibility to inflammatory diseases, including colitis and hepatitis. Clinical analysis reveals that the expression of RPA1 is reduced in patients with ulcerative colitis or other autoinflammatory diseases. Mechanistically, depletion of RPA1 activates ZBP1-RIPK3 signaling through triggering the genomic DNA leakage into cytosol, consequently resulting in T cell necroptosis. This necroptotic T cell death induced by RPA1 deficiency allows the release of damage-associated molecular patterns (DAMPs), which in turn recruits leukocytes and exacerbates inflammatory response. Reciprocally, chemical or genetic inhibition of necroptosis signaling can ameliorate the Rpa1 deficiency-induced inflammatory damage. The studies thus uncover the importance of RPA1-ZBP1-RIPK3 axis in T cell homeostasis and provide a promising strategy for autoinflammatory disease treatment.


Colitis , Necroptosis , Replication Protein A , Animals , Mice , Colitis/metabolism , Homeostasis , Lymphopenia , RNA-Binding Proteins/metabolism , T-Lymphocytes/metabolism , Replication Protein A/metabolism
13.
Small ; 18(50): e2205247, 2022 Dec.
Article En | MEDLINE | ID: mdl-36266932

Polymer dielectrics are key components for electrostatic capacitors in energy, transportation, military, and aerospace fields, where their operation temperature can be boosted beyond 125 °C. While most polymers bear poor thermal stability and severe dielectric loss at elevated temperatures, numerous linear polymers with linear D-E loops and low dielectric permittivity exhibit low loss and high thermal stability. Therefore, the broad prospect of electrostatic capacitors under extreme conditions is anticipated for linear polymers, along with intensive efforts to enhance their energy density with high efficiency in recent years. In this article, an overview of recent progress in linear polymers and their composites for high-energy-density electrostatic capacitors at elevated temperatures is presented. Three key factors determining energy storage performance, including polarization, breakdown strength, and thermal stability, and their couplings are discussed. Strategies including chain modulation, filler selection, and design of topological structure are summarized. Key parameters for electrical and thermal evaluations of polymer dielectrics are also introduced. At the end of this review, research challenges and future opportunities for better performance and industrialization of dielectrics based on linear polymers are concluded.

14.
Small ; 18(28): e2202421, 2022 Jul.
Article En | MEDLINE | ID: mdl-35695338

Polymer dielectrics with excellent thermal stability are the essential core material for thin film capacitors applied in a harsh-environment. However, the dielectric and mechanical properties of polymers are commonly deteriorated with temperature rising. Herein, polyetherimide (PEI)-based nanocomposites contained with SiO2 nanoparticles (SiO2 -NPs) are fabricated by a solution casting method. It is found that the introduction of SiO2 -NPs decreases the electric conductivity and significantly enhances the breakdown strength of the nanocomposites, especially under high temperatures. As a result, the 5 vol% PEI/SiO2 -NPs nanocomposite film displays a superior dielectric energy storage performance, e.g., a discharged energy density of 6.30 J cm-3 and a charge-discharge efficiency of 90.5% measured at 620 MV m-1 and 150 °C. In situ scanning Kelvin probe microscopy characterization indicates that the charge carriers can be trapped in the interfacial regions between the polymer matrix and the SiO2 -NPs till the temperature reaches as high as 150 °C. This work demonstrates an effective strategy to fabricate high-temperature dielectric polymer nanocomposites by embedding inorganic nanoparticles and provides a method for directly detecting charge behavior at the nanoscale inside the matrix.

15.
Adv Mater ; 34(24): e2202181, 2022 Jun.
Article En | MEDLINE | ID: mdl-35405769

Multiplexing physical dimensions to realize multidimensional storage in a single material has been a goal to increase storage density and data security. Multidimensional storage is only achieved in optical storage material (OSM) by far. Poly(vinylidene fluoride) (PVDF), a semicrystalline polymer, is widely studied as a candidate for ferroelectric random access (FeRAM). Herein, the atomic force microscopy (AFM)-based infrared spectroscopy techniqueis used to induce multilevel phase transformations in PVDF ultrathin film on nanometric scales and for writing/readout of IR signals. An optical/ferroelectric multiplexing PVDF memory, where information can be coded with independent four-level optical IR and bilevel ferroelectric signals, is demonstrated. High data security and a storage density up to 180 GBit in.-2 are achieved simultaneously. Owing to the different critical temperature for phase transformation (optical data, <167 °C) and polarization switching (ferroelectric data, <100 °C), the multiplexing memory can function both as optical read-only memory and FeRAM. This work expands material supporting physical dimensions multiplexing beyond OSM for the first time, opening up new opportunities for future high-capacity, multifunctional nano-memory. The strategy proposed here enables on-demand and tunable programming on IR waves, offering prospects for fabrication of active nano-optical devices.

16.
Immun Inflamm Dis ; 9(4): 1383-1393, 2021 12.
Article En | MEDLINE | ID: mdl-34288521

BACKGROUND: Venous thromboembolism (VTE) is one of the leading complications in glioma patients. Neutrophil extracellular traps (NETs) have been reported to play a critical role in the physiopathology of cancer. We aimed to investigate the presence and potential role of NETs in the hypercoagulable state in glioma patients. Moreover, we evaluated the interaction between NETs and endothelial cells (ECs) in glioma patients. METHODS: The plasma levels of NETs were detected by enzyme-linked immunosorbent assay. The NET procoagulant activity was performed based on fibrin formation assays. The NET generation and NET-treated ECs in vitro were observed by confocal microscopy. Activated platelets (PLTs) and PLT-neutrophil aggregates were detected by flow cytometry. RESULTS: Plasma NET markers were significantly higher in stage III/IV glioma patients than in stage I/II glioma patients and healthy subjects. PLTs from glioma patients tended to induce NET formation than those from healthy subjects. NETs contributed to the hypercoagulable state in glioma patients. After ECs were incubated with NETs isolated from stage III/IV glioma patients, they lost their intercellular connections and were converted into procoagulant phenotypes. Combining DNase I and activated protein C markedly decreased endothelial dysfunction. CONCLUSIONS: Our results showed the interaction between NETs and hypercoagulability in glioma patients. Targeting NETs may be a potential therapeutic and prevention direction for thrombotic complications in glioma patients.


Extracellular Traps , Glioma , Thrombophilia , Blood Coagulation , Endothelial Cells , Humans
17.
Immun Inflamm Dis ; 9(3): 1025-1036, 2021 09.
Article En | MEDLINE | ID: mdl-34102007

BACKGROUND: Severe carotid stenosis is a common cause of stroke. In addition, previous clinical studies revealed that patients symptomatic of carotid stenosis suffer from increased episodes of stroke compared with their asymptomatic counterparts. However, the mechanism underlying these differences in the recurrence of stroke remains unclear. OBJECTIVE: The present study aimed to evaluate the levels of neutrophil extracellular traps (NETs) in the plasma of patients with severe carotid stenosis and investigate whether NETs induced procoagulant activity (PCA) in severe carotid stenosis. The study also sought to investigate the interactions between platelets or endothelial cells (ECs) and NETs. METHODS: The levels of NETs in plasma were quantified using enzyme-linked immunosorbent assay (ELISA). In addition, NETting neutrophils and neutrophil-platelet aggregates were detected through flow cytometry. On the other hand, the morphology of NETs formation and endothelial cells were analyzed through confocal microscopy. Finally, the procoagulant activity (PCA) of NETs and endothelial cells were assessed through ELISA and fibrin formation. RESULTS: Patients with symptomatic carotid stenosis patients had significantly higher levels of NETs markers compared with their asymptomatic counterparts and healthy subjects. In addition, increased levels of neutrophil-platelet aggregates induced the generation of NETs in patients with symptomatic carotid stenosis. Moreover, NETs contributed to PCA through tissue factor (TF), in patients with carotid stenosis. Furthermore, NETs disrupted the endothelial barrier and converted endothelial cells (ECs) into PCA to enhance the PCA in patients with carotid stenosis. CONCLUSIONS: The current study revealed differences in the levels of NETs in the plasma of symptomatic and asymptomatic patients suffering from carotid stenosis. The study also uncovered the interaction between NETs and thrombogenicity in carotid stenosis. Therefore, inhibiting NETs may be a potential biomarker and therapeutic target for recurring stroke in severe carotid stenosis.


Carotid Stenosis , Extracellular Traps , Blood Coagulation , Endothelial Cells , Humans , Neutrophils
18.
Science ; 371(6533): 1050-1056, 2021 03 05.
Article En | MEDLINE | ID: mdl-33674493

Polar topological texture has become an emerging research field for exotic phenomena and potential applications in reconfigurable electronic devices. We report toroidal topological texture self-organized in a ferroelectric polymer, poly(vinylidene fluoride-ran-trifluoroethylene) [P(VDF-TrFE)], that exhibits concentric topology with anticoupled chiral domains. The interplay among the elastic, electric, and gradient energies results in continuous rotation and toroidal assembly of the polarization perpendicular to polymer chains, whereas relaxor behavior is induced along polymer chains. Such toroidal polar topology gives rise to periodic absorption of polarized far-infrared (FIR) waves, enabling the manipulation of the terahertz wave on a mesoscopic scale. Our observations should inform design principles for flexible ferroic materials toward complex topologies and provide opportunities for multistimuli conversions in flexible electronics.

19.
Sci Bull (Beijing) ; 66(11): 1080-1090, 2021 Jun 15.
Article En | MEDLINE | ID: mdl-36654342

Large roughness and structure disorder in ferroelectric ultrathin Langmuir-Blodgett (LB) film results in severe space scatter in electrical, ferroelectric and piezoelectric characteristics, thus limiting the nanoscale research and reliability of nano-devices. However, no effective method aiming at large-area uniform organic ferroelectric LB film has ever been reported to date. Herein, we present a facile hot-pressing strategy to prepare relatively large-area poly(vinylidene fluoride) (PVDF) LB film with ultra-smooth surface root mean square (RMS) roughness is 0.3 nm in a 30 µm × 30 µm area comparable to that of metal substrate, which maximized the potential of LB technique to control thickness distribution. More importantly, compared with traditionally annealed LB film, the hot-pressed LB film manifests significantly improved structure uniformity, less fluctuation in ferroelectric characteristics and higher dielectric and piezoelectric responses, owing to the uniform dipole orientation and higher crystalline quality. Besides, different surface charge relaxation behaviors are investigated and the underlying mechanisms are explained in the light of the interplay of surface charge and polarization charge in the case of nanoscale non-uniform switching. We believe that our work not only presents a novel strategy to endow PVDF LB film with unprecedented reliability and improved performance as a competitive candidate for future ferroelectric tunnel junctions (FTJs) and nano electro mechanical systems (NEMS), but also reveals an attracting coupling effect between the surface potential distribution and nanoscale non-uniform switching behavior, which is crucial for the understanding of local transport characterization modulated by band structure, bit signal stability for data-storage application and the related surface charge research, such as charge gradient microscopy (CGM) based on the collection of surface charge on the biased ferroelectric domains.

20.
Chemosphere ; 268: 128843, 2021 Apr.
Article En | MEDLINE | ID: mdl-33172667

Nanomaterials have been widely utilized in human daily life. The interaction between nanoparticles (NPs) and food matrices through oral ingestion is important for fate and potential toxicity of NPs. In this study, the interaction between NPs (i.e., titanium dioxide (TiO2) and zinc oxide (ZnO)) and food matrices (namely sucrose, protein powder, and corn oil) was investigated by use of an in vitro physiological model. Measurement using asymmetrical flow field-flow fractionation (AF4) showed that particle size of TiO2 NPs in saliva fluid decreased from 102 ± 6.21 nm (control) to 69.2 ± 6.90 and 81.9 ± 4.30 nm in protein powder and corn oil. Similar trend was also observed for ZnO. Compared with gastric fluid, micelles formed by corn oil in intestinal fluid further dispersed NPs, as indicated by approximately 11.1% and 13.2% decrease in particle size of TiO2 and ZnO NPs, respectively. Characterization of TEM, FTIR and AFM showed that a layer of biological corona was attached on surface of NPs in protein and oil. The XPS demonstrated that oil bound with NPs through forming covalent bonds, while protein bound with NPs through van der Waals force and electrostatic force for TiO2 and ZnO NPs, respectively. The result here demonstrated the importance of considering food effect when investigating the morphology and behavior of NPs after oral ingestion. This understanding was valuable in assessment of environmental fate and biological effects of NPs.


Metal Nanoparticles , Nanoparticles , Zinc Oxide , Humans , Particle Size , Titanium
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