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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 321: 124678, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38941756

RESUMO

To validate the feasibility and improve the accuracy of water content detection in polyester fabrics using hyperspectral imaging, 150 sets of hyperspectral images of polyester fabrics with varying thicknesses and moisture contents were obtained, and the characteristics of the spectral curves and impact of moisture content were elucidated. In addition, the area and full width at half maximum of the characteristic peaks around 1363 and 1890 nm were determined as spectral characteristic variables. Furthermore, the models of polyester fabric moisture content detection were developed using backpropagation neural networks, and their accuracy was evaluated using correlation coefficient and mean squared error. It was observed that the change in the moisture content of polyester fabrics not only affected the reflectance of the overall spectral curve of polyester fabrics but also altered the position and overall shape of the characteristic peaks. As the moisture content increased, the proportion of pure water spectra in the mixed spectra of water-containing polyester fabrics also increased, leading to a change in the overall shape of the characteristic peaks of polyester fabrics. Because of the overlap between the near-infrared absorption bands of pure water and the polyester fabric around 1363 and 1890 nm, the area and full width at half maximum of the characteristic peaks were considered to be more representative than the reflection for modeling. The established backpropagation neural network-based moisture content quantitative detection model has shown extremely high detection accuracy, with the correlation coefficient for the test set being higher than 0.999 and the root mean square error being lower than 0.3 %, indicating that the detection error of moisture content was only about 0.3 wt%.

2.
Anal Chem ; 96(21): 8682-8688, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38757179

RESUMO

Programming ultrasensitive and stimuli-responsive DNAzyme-based probes holds great potential for on-demand biomarker detection. Here, an optically triggered DNAzyme platform was reported for on-demand activation-sensitive electrochemiluminescence (ECL) c-myc mRNA analysis. In this design, the sensing and recognition function of the split DNAzyme (SDz) probe was silent by engineering a blocking sequence containing a photocleavable linker (PC-linker) group at a defined site that could be indirectly cleaved by 302 nm ultraviolet (UV) light. When the SDz probes were assembled on the Au nanoparticles and potassium (K) element doped graphitic carbon nitride nanosheet (K-doped g-C3N4) covered electrode, UV light activation induces the configurational switching and consequently the formation of an active DNAzyme probe with the help of target c-myc mRNA, allowing the cleavage of the substrate strand by magnesium ions (Mg2+). Thus, the release of a ferrocene (Fc)-labeled DNAzyme 2 strand contributed to an extreme ECL signal recovery. In the meantime, the released target c-myc mRNA combined another inactive SDz motif to form active DNAzyme and repeat the cyclic cleavage reaction, resulting in the signal amplification. Furthermore, according to the responses toward two other designed nPC-SDz and m-SDz probes, we demonstrated that controlled UV light mediated photoactivation of the DNAzyme biosensor "on demand" effectively constrained the ECL signal to the mRNA of interest. Moreover, false positive signals could also be avoided due to such a photoactivation design with UV light. Therefore, this study provided a simple methodology that may be broadly applicable for investigating the mRNA-associated physiological events that were difficult to access using traditional DNAzyme probes.


Assuntos
DNA Catalítico , Técnicas Eletroquímicas , Medições Luminescentes , RNA Mensageiro , DNA Catalítico/metabolismo , DNA Catalítico/química , Técnicas Eletroquímicas/métodos , RNA Mensageiro/análise , Humanos , Raios Ultravioleta , Técnicas Biossensoriais/métodos , Ouro/química , Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Processos Fotoquímicos , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Grafite/química , Limite de Detecção , Compostos de Nitrogênio
3.
Materials (Basel) ; 17(6)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38541561

RESUMO

The purpose of this study is to use acoustic emission (AE) technology to explore the changes in the interface and mechanical properties of GF/VER composite materials after being treated with NaOH and to analyze the optimal modification conditions and damage propagation process. The results showed that the GF surface became rougher, and the number of reactive groups increased after treating the GF with a NaOH solution. This treatment enhanced the interfacial adhesion between the GF and VER, which increased the interfacial shear strength by 25.31% for monofilament draw specimens and 27.48% for fiber bundle draw specimens compared to those before the GF was modified. When the modification conditions were a NaOH solution concentration of 2 mol/L and a treatment time of 48 h, the flexural strength of the GF/VER composites reached a peak value of 346.72 MPa, which was enhanced by 20.96% compared with before the GF was modified. The process of damage fracture can be classified into six types: matrix cracking, interface debonding, fiber pullout, fiber relaxation, matrix delamination, and fiber breakage, and the frequency ranges of these failure mechanisms are 0~100 kHz, 100~250 kHz, 250~380 kHz, 380~450 kHz, 450~600 kHz, and 600 kHz and above, respectively. This paper elucidates the fracture process of GF/VER composites in three-point bending. It establishes the relationship between the AE signal and the interfacial and force properties of GF/VER composites, realizing the classification of the damage process and characterizing the mechanism. The frequency ranges of damage types and failure mechanisms found in this study offer important guidance for the design and improvement of composite materials. These results are of great significance for enhancing the interfacial properties of composites, assessing the damage and fracture behaviors, and implementing health monitoring.

4.
Waste Manag ; 177: 266-277, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38354634

RESUMO

With the rapid advancement of electric vehicles (EVs), the burgeoning increase in used power batteries necessitates the development of efficient battery recycling e-platforms. A key challenge in this field is the mismatch between supply and demand. In response, a dynamic optimization model is proposed to capture the non-equalizing supply-demand relationship and its linkage over continuous periods to enable dynamic simulations and predictions of transaction volume changes. Meanwhile, pricing and commission-setting strategies are optimized based on the objectives of maximizing social welfare and platform revenue. The result shows that due to the lower recycling volumes that result, increasing the recycling price usually increases platform revenues, exacerbates environmental costs, and leads to lower social welfare. Moreover, platform revenues are more sensitive to commission rates than social welfare, which is more vulnerable to recycling prices. Furthermore, prioritizing social welfare leads to a higher recycling volume compared to prioritizing revenue, but it also creates an imbalance between supply and demand, destabilizing the recycling market. With the dynamic pricing and commission strategies, this study enriches the literature in the third-party recycling mode for power batteries, offering a novel perspective that is more aligned with real-world operational conditions. Our findings help platforms clarify the impact of pricing and commission decisions on platform revenue and social welfare and thereby provide support for their decision optimization.


Assuntos
Fontes de Energia Elétrica , Eletricidade , Reciclagem
5.
Micromachines (Basel) ; 14(11)2023 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-38004870

RESUMO

Bridge sensors are widely used in military and civilian fields, and their demand gradually increases each year. Digital sensors are widely used in the military and civilian fields. High-precision and low-power analog-to-digital converters (ADCs) as sensor read-out circuits are a research hotspot. Sigma-delta ADC circuits based on switched-capacitor topology have the advantages of high signal-to-noise ratio (SNR), good linearity, and better compatibility with CMOS processes. In this work, a fourth-order feed-forward sigma-delta modulator and a digital decimation filter are designed and implemented with a correlated double sampling technique (CDS) to suppress pre-integrator low-frequency noise. This work used an active pre-compensator circuit for deep phase compensation to improve the system's stability in the sigma-delta modulator. The modulator's local feedback factor is designed to be adjustable off-chip to eliminate the effect of process errors. A three-stage cascade structure was chosen for the post-stage digital filter, significantly reducing the number of operations and the required memory cells in the digital circuit. Finally, the layout design and engineering circuit were fabricated by a standard 0.35 µm CMOS process from Shanghai Hua Hong with a chip area of 9 mm2. At a 5 V voltage supply and sampling frequency of 6.144 MHz, the modulator power consumption is 13 mW, the maximum input signal amplitude is -3 dBFs, the 1 Hz dynamic range is about 118 dB, the modulator signal-to-noise ratio can reach 110.5 dB when the signal bandwidth is 24 kHz, the practical bit is about 18.05 bits, and the harmonic distortion is about -113 dB, which meets the design requirements. The output bit stream is 24 bits.

6.
Nat Commun ; 14(1): 5348, 2023 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-37660126

RESUMO

The manipulation of internal interactions at the molecular level within biological fibers is of particular importance but challenging, severely limiting their tunability in macroscopic performances and applications. It thus becomes imperative to explore new approaches to enhance biological fibers' stability and environmental tolerance and to impart them with diverse functionalities, such as mechanical recoverability and stimulus-triggered responses. Herein, we develop a dynamic imine fiber chemistry (DIFC) approach to engineer molecular interactions to fabricate strong and tough protein fibers with recoverability and actuating behaviors. The resulting DIF fibers exhibit extraordinary mechanical performances, outperforming many recombinant silks and synthetic polymer fibers. Remarkably, impaired DIF fibers caused by fatigue or strong acid treatment are quickly recovered in water directed by the DIFC strategy. Reproducible mechanical performance is thus observed. The DIF fibers also exhibit exotic mechanical stability at extreme temperatures (e.g., -196 °C and 150 °C). When triggered by humidity, the DIFC endows the protein fibers with diverse actuation behaviors, such as self-folding, self-stretching, and self-contracting. Therefore, the established DIFC represents an alternative strategy to strengthen biological fibers and may pave the way for their high-tech applications.


Assuntos
Engenharia Química , Iminas , Iminas/química , Seda
7.
Eur J Pharm Biopharm ; 189: 152-164, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37336365

RESUMO

An oral galactosylated carboxymethyl chitosan polymeric nanomicelles (Gal-N-CMCS NPs) embedded in chitosan-alginate hydrogel (CA-Gel) was developed to load cyclosporine A (CyA) as therapeutic agents against ulcerative colitis (UC). Galactose modified CMCS with macrophage targeting characteristic and CyA via a simple ultrasonication method to form Gal-N-CMCS/CyA NPs, and mixed CA-Gel to acquire the final formulation (Gal-N-CMCS/CyA Gel). The generated Gal-N-CMCS/CyA NPs displayed a desirable particle size (206.8 nm), negative surface charge (-19.5 mV), and high encapsulating efficiency (89.6 %). The morphology and release profiles were also charactered by transmission electron microscope [1] and dialysis method, respectively. Strikingly, the mucus penetration of Gal-N-CMCS/CyA NPs exceeded 90 % within 90 min. The Gal-N-CMCS NPs internalized by macrophages were 3.3-fold higher than CMCS-N NPs, thereby, enhancing the anti-inflammatory activities of NPs. Meanwhile, these NPs exhibited excellent biocompatibility, reduced the toxic effect of CyA, and targeting ability on inflammatory macrophages both in vitro and in vivo. Most importantly, in vivo studies revealed that CyA NPs could efficiently target the inflamed colon, remarkably alleviate inflammation, repair mucosal and reconstructed colonic epithelial barriers in UC mice induced by dextran sulfate sodium (DSS) via Toll-like receptor 4 -Nuclear factor kappa-B (TLR4-NF-κB) pathway. Our findings suggest that these high-performance and facilely fabricated Gal-N-CMCS/CyA NPs could be developed as a promising drug carrier for oral UC treatment.


Assuntos
Quitosana , Colite Ulcerativa , Nanopartículas , Animais , Camundongos , Colite Ulcerativa/tratamento farmacológico , Ciclosporina , Polímeros , Sulfato de Dextrana/efeitos adversos
8.
Front Psychol ; 14: 1105959, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36895736

RESUMO

Human health and marine life are facing the hazards and threats of plastic waste. China is the world's largest producer and consumer of disposable plastic products, thus paying more attention to the threats and challenges of single-use plastics products in China is urgent. This study aims to explore the intention to purchase single-use plastic products based on the theory of planned behavior. Data collection using self-reported questionnaires, and 402 valid questionnaires were obtained, thus analyzed using Amos 22.0 and SPSS 18.0 software. Results indicate that attitude, perceived behavioral control, normative social influence, informational social influence, and positive anticipated emotion positively affect intention to purchase single-use plastic products. Meanwhile, positive anticipated emotion positively moderates the relationship between normative social influence and intention to purchase single-use plastic products, but negatively moderates the relationship between informational social influence and intention to purchase single-use plastic products. This research provides some theoretical and policy implications to help relevant agencies design targeted interventions to address environmental issues related to single-use plastic consumption.

9.
Environ Sci Pollut Res Int ; 30(5): 11959-11977, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36103067

RESUMO

In this study, the degradation efficiency and reaction mechanisms of diclofenac (DCF), a nonsteroidal anti-inflammatory drug, by the combination of ferrate (Fe(VI) and peroxymonosulfate (PMS) (Fe(VI)/PMS) were systematically investigated. The higher degradation efficiency of DCF in Fe(VI)/PMS system can be obtained than that in alone persulfate (PS), Fe(VI), PMS, or the Fe(VI)/PS process at pH 6.0. DCF was efficiently removed in Fe(VI)/PMS process within a wide range of pH values from 4.0 to 8.0, with higher degradation efficiency in acidic conditions. The increasing reaction temperature (10 to 30 ℃), Fe(VI) dose (6.25 to 100 µM), or PMS concentration (50 to 1000 µM) significantly enhanced the DCF degradation. The existences of HCO3¯, Cl¯, and humic acid (HA) obviously inhibited the DCF removal. Electron paramagnetic resonance (EPR), free radical quenching, and probing experiments confirmed the existence of sulfate radicals (SO4•¯), hydroxyl radicals (•OH), and Fe(V)/ Fe(IV), which are responsible for DCF degradation in Fe(VI)/PMS system. The variations of TOC removal ratio reveal that the adsorption of organics with ferric particles, formed in the reduction of Fe(VI), also were functioned in the removal process. Sixteen DCF transformation byproducts were identified by UPLC-QTOF/MS, and the toxicity variation was evaluated. Consequently, eight reaction pathways for DCF degradation were proposed. This study provides theoretical basis for the utilization of Fe(VI)/PMS process.


Assuntos
Diclofenaco , Poluentes Químicos da Água , Oxirredução , Ferro , Peróxidos , Poluentes Químicos da Água/análise
10.
Adv Mater ; 34(19): e2200842, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35262209

RESUMO

The utility of unfolded structural proteins with diverse sequences offers multiple potentials to create functional biomaterials. However, it is challenging to overcome their structural defects for the development of biological fibers with a combination of high strength and high toughness. Herein, robust fibers from a recombinant unfolded protein consisting of resilin and supercharged polypeptide are fabricated via wet-spinning approaches. Particularly, the highly ordered structures induced by supramolecular complexation significantly improve the fiber's mechanical performance. In contrast to chemical fibers with high strength and low toughness (or vice versa), the present fibers demonstrate exceptional high strength and super-toughness, showing a breaking strength of ≈550 MPa and a toughness of ≈250 MJ m-3 , respectively, surpassing many polymers and artificial protein fibers. Remarkably, the outstanding biocompatibility and superior mechanical properties allow application of the constructed fiber patches for efficient abdominal hernia repair in rat models. In stark contrast to clinical patches, there is no observed tissue adhesion by this treatment. Therefore, this work provides a new type of engineered protein material for surgical applications.


Assuntos
Hérnia Abdominal , Peptídeos , Animais , Materiais Biocompatíveis/farmacologia , Peptídeos/química , Polímeros/química , Ratos , Proteínas Recombinantes/química
11.
Environ Geochem Health ; 44(9): 3157-3171, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35129706

RESUMO

Achieving carbon neutrality has become a global consensus, and plenty of measures and policies have been proposed in various industries to obtain this ambitious goal. As an innovative and radical environmental policy tool, personal carbon trading (PCT) policy which aims to reduce carbon emissions from the private consumption sector has aroused the attention. For a new policy tool, public support and acceptance is critical to obtain policy legitimacy and policy implementation. To implement PCT policy smoothly, the current research aims to explore the antecedents of public acceptance. From the emotional reaction perspective, this research mainly evaluated how political trust, perceived uncertainty and associated emotions matter for public acceptance of PCT policy. Based on the survey data, this research revealed that political trust has a direct positive impact on public acceptance of PCT policy. Meanwhile, political trust also has an indirect impact on public acceptance of PCT policy via emotions. Specifically, political trust is positively associated with positive emotions and negatively associated with negative emotions. Positive emotions promote public to accept PCT policy, while negative emotions inhibit public to accept PCT policy. The negative emotions exert a more powerful impact on public acceptance than positive emotions. Additionally, we found that perceived uncertainty exerts a negative effect on public acceptance and negatively regulates the relationship between political trust and public acceptance. That is, perceived uncertainty has a significant substitution effect on political trust. According to the research findings, policy implications to improve public acceptance of PCT policy were explored.


Assuntos
Carbono , Confiança , Políticas , Inquéritos e Questionários , Incerteza
12.
Environ Geochem Health ; 44(9): 3007-3020, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34993735

RESUMO

Personal carbon trading (PCT) policy has been considered as an innovative and radical environmental policy tool to achieve carbon neutrality in private sector. For a new policy tool, resident acceptance is extremely vital and should be considered first and put in a vital position. The aim of this research is to understand resident acceptance of PCT policy and examine what drives resident acceptance and opposition of PCT policy. Based on a national survey in China, this research analyzed the level of resident acceptance toward PCT policy and its associated driving factors. Results delineated that residents are more likely to accept the piloting of PCT policy in other city and more positive toward the implementation of PCT policy in the next five years, but less likely to accept the piloting of PCT policy in their city and more negative toward the immediate implementation of PCT policy across the country. Furthermore, this research uncovered that residents from different regions and living areas and with different income level have different acceptable level to PCT policy. Additionally, this research found that resident acceptance of PCT policy is significantly affected by PCT knowledge, perceived benefit, perceived cost, perceived policy effectiveness and environmental awareness. However, compared with other factors, environmental awareness plays a limited role in improving resident acceptance of PCT policy. On the basis of research findings, measures to improve resident acceptance of PCT policy were discussed.


Assuntos
Carbono , Política Ambiental , Carbono/análise , China , Políticas
13.
Artigo em Inglês | MEDLINE | ID: mdl-35010749

RESUMO

The promotion of information flow reinforces the interactive cooperation and evolutionary process among cities. In the information age, public online search is a typical behavior of Internet society, which is the key to information flow generation and agglomeration. In this study, we attempt to explore the evolutionary characteristics of intercity networks driven by public online social behavior in the information age and construct an information flow network (IFN) from the perspective of public search attention. We also explore the evolution of the IFN in terms of the whole network, node hierarchy, and subgroup aggregation. Meanwhile, we also discuss the impact of the sustainable driving factors on the IFN. Finally, an empirical study was conducted in Guanzhong Plain Urban Agglomeration (GPUA). Our results show that: (1) the information flow in GPUA fluctuating upward in the early study period and gradually decreasing in the later study period. However, the agglomeration degree of information flow in the urban agglomeration continues to increase. (2) The hierarchical structure of urban nodes in GPUA presents a trend of "high in the middle and low on both sides", and the formation of subgroups is closely related to geographic location. (3) The driving factors all impacting the IFN include public ecology, resource investment, information infrastructure, and economic foundation. This study provides theoretical and practical support for exploring the intercity network and promotes the sustainable urban development.


Assuntos
Desenvolvimento Sustentável , Urbanização , Atenção , China , Cidades , Reforma Urbana
14.
Chemosphere ; 278: 130388, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33819892

RESUMO

Nitrite (NO2-) reduction by carbon dioxide anion radical (CO2•-) from the activation of small molecule carboxylic acid was investigated to selectively reduce nitrite to nitrogen gas (N2). However, the CO2•- generation efficiency from the activation of small molecule carboxylic acid needs to be enhanced to increase the NO2- reduction efficiency. In this study, a novel and promising process for selective NO2- reduction was proposed based on activation of oxalic acid (OA) by UV radiation coupled with Fe3+. In Fe(III)/OA/UV system, the activation of OA by photo-induced electron transfer process of Fe(III)-oxalate complex and by •OH radical from the photolysis of Fe3+ or NO2- could promote the generation of CO2•- radical, which enhanced the NO2- reduction. The 100% removal efficiency of NO2-, 94.72% of total nitrogen (TN) and 94.72% of selectivity for N2 were achieved in Fe(III)/OA/UV/NO2- system, at the Fe3+ dosage of 8 mmol/L, initial pH of 1.70, OA dosage of 16 mmol/L, initial NO2- concentration of 30 mg N/L, and reaction time of 180 min. CO2•- radical played a significant role in the reduction of NO2- by Fe(III)/OA/UV system based on the inhibition experiments in which methyl violet was used as a quenching agent of CO2•- radical. Based on the results from batch experiments and FTIR analysis, the activation mechanism of OA and selective reduction mechanism of NO2- in Fe(III)/OA/UV system was proposed.


Assuntos
Dióxido de Carbono , Nitritos , Compostos Férricos , Nitrogênio , Compostos Orgânicos , Oxirredução
15.
Dalton Trans ; 50(6): 2014-2017, 2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33544105

RESUMO

pH is a critical parameter that has found unique application in magnetic resonance imaging (MRI) mapping acidity in tissues. This study reports a series of Dy-based MR probes that show innovative T2ex features, governed by proton catalyzed events. With an increase of pH from 5.5 to 8.0, the r2ex relaxivity increased dramatically, while the r1 relaxivity remained unchanged. The resulting r2ex/r1 allowed for concentration-independent and direct mapping of physiologically relevant pH ranges.


Assuntos
Amidas/química , Meios de Contraste/química , Disprósio/química , Imageamento por Ressonância Magnética/métodos , Compostos Organometálicos/química , Concentração de Íons de Hidrogênio
16.
Angew Chem Int Ed Engl ; 59(21): 8148-8152, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32134537

RESUMO

Silk-protein-based fibers have attracted considerable interest due to their low weight and extraordinary mechanical properties. Most studies on fibrous proteins focus on the recombinant spidroins, but these fibers exhibit moderate mechanical performance. Thus, the development of alternative structural proteins for the construction of robust fibers is an attractive goal. Herein, we report a class of biological fibers produced using a designed chimeric protein, which consists of the sequences of a cationic elastin-like polypeptide and a squid ring teeth protein. Remarkably, the chimeric protein fibers exhibit a breaking strength up to about 630 MPa and a corresponding toughness as high as about 130 MJ m-3 , making them superior to many recombinant spider silks and even comparable to some native counterparts. Therefore, this strategy is a novel concept for exploring bioinspired ultrastrong protein materials through the development of new types of structural chimeric proteins.


Assuntos
Peptídeos/metabolismo , Proteínas/metabolismo , Proteínas Recombinantes de Fusão/química , Sequência de Aminoácidos , Animais , Decapodiformes/metabolismo , Módulo de Elasticidade , Elastina/química , Glutaral/química , Peptídeos/química , Peptídeos/genética , Engenharia de Proteínas , Proteínas/química , Proteínas/genética , Proteínas Recombinantes de Fusão/biossíntese , Resistência à Tração
17.
Angew Chem Int Ed Engl ; 59(11): 4344-4348, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-31873970

RESUMO

Proteins used for the formation of light weight and mechanically strong biological fibers are typically composed of folded rigid and unfolded flexible units. In contrast to fibrous proteins, globular proteins are generally not regarded as a good candidate for fiber production due to their intrinsic structural defects. Thus, it is challenging to develop an efficient strategy for the construction of mechanically strong fibers using spherical proteins. Herein, we demonstrate the production of robust protein fibers from bovine serum albumin (BSA) using a microfluidic technique. Remarkably, the toughness of the fibers was up to 143 MJ m-3 , and after post-stretching treatment, their breaking strength increased to almost 300 MPa due to the induced long-range ordered structure in the fibers. The performance is comparable to or even higher than that of many recombinant spider silks or regenerated silkworm fibers. Thus, this work opens a new way for making biological fibers with high performance.


Assuntos
Fibroínas/química , Microfluídica/métodos , Soroalbumina Bovina/química , Animais , Bombyx , Reagentes de Ligações Cruzadas/química , Elasticidade , Glutaral/química , Seda/química , Aranhas , Estresse Mecânico , Resistência à Tração
18.
Angew Chem Int Ed Engl ; 58(50): 18286-18289, 2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31589797

RESUMO

Chiral α-hydroxyl acids are of great importance in chemical synthesis. Current methods for recognizing their chirality by 1 H NMR are limited by their small chemical shift differences and intrinsic solubility problem in organic solvents. Herein, we developed three YbDO3A(ala)3 derivatives to recognize four different commercially available chiral α-hydroxyl acids in aqueous solution through 1 H NMR and chemical exchange saturation transfer (CEST) spectroscopy. The shift difference between chiral α-hydroxyl acid observed by proton and CEST NMR ranged from 15-40 and 20-40 ppm, respectively. Our work demonstrates for first time, that even one chiral center on the side-arm chain of cyclen could set the stage for rotation of the other two non-chiral side chains into a preferred position. This is ascribed to the lower energy state of the structure. The results show that chiral YbDO3A-like complexes can be used to discriminate chiral α-hydroxyl acids with a distinct signal difference.

19.
ACS Appl Mater Interfaces ; 11(26): 23616-23622, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31252479

RESUMO

Inspired by the helicoidally organized microstructure of stomatopods' smasher dactyl club, a type of impact-resistant composite film reinforced with periodic helicoidal nanofibers is designed and fabricated, which reproduces the structural complexity of the natural material. To periodically align nanofibers in a helicoidal structure, an electrospinning system is developed to better control the alignment of electrospun nanofibers. When the nanofiber scaffold is embedded in an epoxy matrix, the presence of a hierarchical structure allows the composite films to achieve properties well beyond their constituents. The composite film exhibits excellent optical transparency and mechanical properties, such as enhanced tensile strength, ductility, and defect tolerance. With elegant design mimicking nature's hierarchical structure at multilength scales, the composite films could effectively release the impact energy and greatly increase the impact resistance, suggesting that the transparent composite films are promising protective layers suitable for various applications.

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