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1.
Nat Commun ; 12(1): 5768, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34599179

RESUMO

Selective separation of propyne/propadiene mixture to obtain pure propadiene (allene), an essential feedstock for organic synthesis, remains an unsolved challenge in the petrochemical industry, thanks mainly to their similar physicochemical properties. We herein introduce a convenient and energy-efficient physisorptive approach to achieve propyne/propadiene separation using microporous metal-organic frameworks (MOFs). Specifically, HKUST-1, one of the most widely studied high surface area MOFs that is available commercially, is found to exhibit benchmark performance (propadiene production up to 69.6 cm3/g, purity > 99.5%) as verified by dynamic breakthrough experiments. Experimental and modeling studies provide insight into the performance of HKUST-1 and indicate that it can be attributed to a synergy between thermodynamics and kinetics that arises from abundant open metal sites and cage-based molecular traps in HKUST-1.

2.
Nanoscale ; 13(32): 13735-13745, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34477648

RESUMO

Tumor radioresistance is a major issue in radiotherapy. To address it, a pH-responsive nanoradiosensitizer was synthesized employing a simple method. Initially, chloroplatinic acid was reduced by human serum albumin (HSA) to form HSA-wrapped Pt@HSA nanoparticles (NPs). Subsequently, cinnamicaldehyde (CA) was grafted on Pt@HSA via aldimine condensation to obtain nanoradiosensitizer Pt@HSA/CA NPs. CA would be released in tumor cells (pH = 5.5) to induce the production of reactive oxygen species, including H2O2, ˙OH, etc. The increased decomposition of H2O2 catalyzed by the NPs resulted in enhanced production of oxygen, leading to hypoxia relief of the tumor cells, which is beneficial for radiotherapy. Due to the high X-ray attenuation coefficient of Pt, Pt@HSA/CA NPs enhance the energy deposition of radiation. Cytotoxicity assay revealed that Pt@HSA/CA NPs resulted in a cell death rate of 77%, which was 24.4% higher than that of Pt@HSA NPs even under low-dose X-ray irradiation of 4 Gy. Colony formation assay demonstrated that the sensitization enhancement ratio was 1.37, indicating that Pt@HSA/CA NPs displayed remarkable radiosensitizing ability. Notably, in vivo results indicated that the NPs could increase the tumor inhibition rate to 91.2% with negligible side effects to normal tissues. These results demonstrate that Pt@HSA/CA NPs had outstanding tumor curative efficacy and hypotoxicity.


Assuntos
Peróxido de Hidrogênio , Nanopartículas , Linhagem Celular Tumoral , Humanos , Concentração de Íons de Hidrogênio , Estresse Oxidativo
3.
Artigo em Inglês | MEDLINE | ID: mdl-34499385

RESUMO

Self-assembly of N,N,N ' ,N '-tetrakis(4-carboxyphenyl)-1,4-phenylenediamine with the help of different solvents provides isostructural hydrogen-bonded organic frameworks (HOF-30). Single crystal X-ray diffraction (SCXRD) analysis reveals HOF-30 possesses 3D ten-fold interpenetrated dia nets connected by two kinds of hydrogen bonds, namely solvent-bridged carboxyl dimers and carboxyl···carboxyl dimers. Degassing treatment for HOF-30 yields HOF-30a still with 3D ten-fold interpenetrated dia nets but linked with sole carboxyl···carboxyl dimers. Reversible hydrogen-bond-to-hydrogen-bond transformation between solvent-bridged·carboxyl dimers in HOF-30 and carboxyl···carboxyl dimers in HOF-30a has been unveiled by single crystal and powder X-ray diffraction. In addition, HOF-30a enables the selective adsorption of propyne over propylene according to the single component sorption and breakthrough experiments. The preferred propyne location in HOF has also been identified by SCXRD test.

4.
Biomater Sci ; 9(18): 6308-6324, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34519724

RESUMO

As an excellent candidate material for nano-sensitizers, gold nanostructures have shown great potential in radiotherapy. Nevertheless, severe hypoxia and low accumulation of nanomedicine caused by poor perfusion at the tumor site have significantly reduced radiotherapy efficacy. Vascular normalization has gained attention owing to its ability to relieve hypoxia and increase perfusion. The synergistic therapy of tumor vascular normalization and radiotherapy has become a new option to increase anti-cancer efficacy. However, the commonly used strategy of suppressing a single growth factor to induce vascular normalization is limited by tumor compensatory effects. In this work, we developed a strategy to inhibit oxidative stress in tumors by generating chelating agents in response to hydrogen peroxide, thereby inhibiting multi-angiogenic factors simultaneously to normalize blood vessels. Concretely, sodium alginate (SA) reacted with 8-quinoline boric acid (QBA) to form SA-QBA. Then gold nanoparticles (Au NPs) were modified with SA-QBA to obtain Au@SA-QBA. The system was simple in structure and could generate 8HQ in response to H2O2in vitro to inhibit oxidative stress and reduce the expression of VEGF, bFGF, and Ang-2. In vivo, the perfusion unit (PU) increased by 78% after Au@SA-QBA treatment, and the coverage of pericytes increased by 32%, which in turn induced vascular normalization. In addition, blood routine and blood biochemical tests confirmed its good biocompatibility and 8HQ was not detected in the supernatant after homogenization of major organs. More importantly, after the synergistic treatment of vascular normalization and radiotherapy (4 Gy), the tumor growth inhibition rate was increased by 38.6% compared to the Au@SA-treated group with negligible side effects to normal tissues.


Assuntos
Nanopartículas Metálicas , Radiossensibilizantes , Linhagem Celular Tumoral , Ouro , Nanomedicina
5.
Artigo em Inglês | MEDLINE | ID: mdl-34369054

RESUMO

Herein, we describe the synthesis of two highly crystalline, robust, hydrophilic covalent organic frameworks (COFs) that display intrinsic proton conduction by the Grotthuss mechanism. The enriched redox-active azo groups in the COFs can undergo a proton-coupled electron transfer reaction for energy storage, making the COFs ideal candidates for pseudocapacitance electrode materials. After in situ hybridization with carbon nanotubes, the composite exhibited a high three-electrode specific capacitance of 440 F g-1 at the current density of 0.5 A g-1 , among the highest for COF-based supercapacitors, and can retain 90 % capacitance even after 10 000 charge-discharge cycles. This is the first example using Grotthuss proton-conductive organic materials to create pseudocapacitors that exhibited both high power density and energy density. The assembled asymmetric two-electrode supercapacitor showed a maximum energy density of 71 Wh kg-1 with a maximum power density of 42 kW kg-1 , surpassing that of all reported COF-based systems.

6.
ACS Appl Mater Interfaces ; 13(27): 32058-32066, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34197071

RESUMO

Exploration of novel material platforms to protect biological preservatives and realize intelligent regulation during fermentation is of great significance in industry. Herein, we established an intelligent responsive platform by introducing antimicrobial biomolecules (nisin) into rationally designed covalent organic frameworks (COFs), resulting in a new type of "smart formulation", which could responsively inhibit microbial contamination and ensure the orderly progression of the fermentation process. The encapsulated biomolecules retained their activity while exhibiting enhanced stability and pH-responsive releasing process (100% bacteriostatic efficiency at a pH of 3), which can ingeniously adapt to the environmental variation during the fermentation process and smartly fulfill the regulation needs. Moreover, the nisin@COF composites would not affect the fermentation strains. This study will pave a new avenue for the preparation of highly efficient and intelligent antimicrobial agents for the regulation of the fermentation process and play valuable roles in the drive toward green and sustainable biomanufacturing.


Assuntos
Fermentação/efeitos dos fármacos , Estruturas Metalorgânicas/química , Nisina/química , Nisina/farmacologia , Desenho de Fármacos , Concentração de Íons de Hidrogênio
7.
Artigo em Inglês | MEDLINE | ID: mdl-34075668

RESUMO

Fabricating covalent organic frameworks (COFs) membranes with tight structure, which can fully utilize well-defined framework structure and thus achieve superior conduction performance, remains a grand challenge. Herein, through molecular precursor engineering of COFs, we reported the fabrication of tight COFs membrane with the ever-reported highest hydroxide ion conductivity over 200 mS cm-1 at 80 °C, 100 % RH. Six quaternary ammonium-functionalized COFs were synthesized by assembling functional hydrazides and different aldehyde precursors. In an organic-aqueous reaction system, the impact of the aldehyde precursors with different size, electrophilicity and hydrophilicity on the reaction-diffusion process for fabricating COFs membranes was elucidated. Particularly, more hydrophilic aldehydes were prone to push the reaction zone from the interface region to the aqueous phase of the reaction system, the tight membranes were thus fabricated via phase-transfer polymerization process, conferring around 4-8 times the anion conductivity over the loose membranes via interfacial polymerization process.

8.
ACS Biomater Sci Eng ; 7(7): 3434-3445, 2021 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34129333

RESUMO

The method of tumor microenvironment (TME)-responsive aggregation has become a promising approach to enhance treatment effect by improving the accumulation of nanoparticles in tumors. The enzymatic cross-linking strategy has widely attracted attention owing to its good aggregation stability and biocompatibility. However, the enzymes in nontumor tissue can also catalyze the cross-linking reaction and reduce accumulation of nanoparticles in tumor. In this work, a "dual key"-responsive strategy is utilized to construct a transglutaminase (TGase)/pH-responsive radiosensitizer (Au@TAcoGal) with specific aggregation behavior in hepatic tumor cells. Au@TAcoGal can retain its stability in blood circulation (pH 7.4) even in the presence of TGase in plasma. On reaching tumor sites, it can be endocytosed by hepatoma cells by the active targeting of phenylboronic acid (PBA) and aggregated under acidity and overexpression of TGase in cells. Due to its specific accumulation in hepatoma cells, radiotherapy can be operated under a lower dose of X-ray. The results show that the cellular accumulation of Au@TAcoGal increases by 30-70%, and the cell survival rate is less than 25% under X-ray irradiation. The antineoplastic results show that Au@TAcoGal exhibits a higher therapeutic effect, and the tumor inhibition rate can reach 84.21%.


Assuntos
Ouro , Neoplasias Hepáticas , Linhagem Celular Tumoral , Humanos , Concentração de Íons de Hidrogênio , Neoplasias Hepáticas/tratamento farmacológico , Nanopartículas Metálicas , Radiossensibilizantes , Transglutaminases , Microambiente Tumoral
9.
J Am Chem Soc ; 143(23): 8654-8660, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34077659

RESUMO

The development of new techniques and materials that can separate ethylene from ethane is highly relevant in modern applications. Although adsorption-based separation techniques using metal-organic frameworks (MOFs) have gained increasing attention, the relatively low stability (especially water resistance) and unscalable synthesis of MOFs severely limit their application in real industrial scenarios. Addressing these challenges, we rationally designed and synthesized two new C2H6-selective MOF adsorbents (NKMOF-8-Br and -Me) with ultrahigh chemical and thermal stability, including water resistance. Attributed to the nonpolar/hydrophobic pore environments and appropriate pore apertures, the MOFs can capture C2 hydrocarbon gases at ambient conditions even in high humidity. The single-crystal structures of gas@NKMOF-8 realized the direct visualization of adsorption sites of the gases. Both the single-crystal data and simulated data elucidate the mechanism of selective adsorption. Moreover, the NKMOF-8 possesses high C2H6 adsorption capacity and high selectivity, allowing for efficient C2H6/C2H4 separation, as verified by experimental breakthrough tests. Most importantly, NKMOF-8-Br and -Me can be scalably synthesized through stirring at room temperature in minutes, which confers them with great potential for industrial application. This work offers new adsorbents that can address major chemical industrial challenges and provides an in-depth understanding of the gas binding sites in a visual manner.

10.
J Mater Chem B ; 9(21): 4365-4379, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34013945

RESUMO

As a radiotherapy sensitizer, gold-based nanomaterials can significantly enhance radiotherapy efficacy. However, the severe hypoxia and the low accumulation of nanomedicine at the tumor site caused by poor perfusion have seriously affected the effect of radiotherapy. Tumor vascular normalization has emerged as a new strategy for increasing the efficacy of radiotherapy due to its ability to relieve hypoxia and increase perfusion. However, a commonly used approach of blocking a single growth factor to induce vascular normalization is limited by the compensation effect of evasive drug resistance. In this work, we developed a strategy to simultaneously reduce the expression of multi-angiogenic growth factors by suppressing the oxidative stress effects in tumor. Herein, gold nanoparticles (Au NPs) were modified with 8-hydroxyquinoline (HQ) to obtain AuHQ. This system has a simple structure and could inhibit the production of reactive oxygen species in tumor cells by chelating iron ions, and attenuating the expression of angiopoietin-2, vascular endothelial growth factor and basic fibroblast growth factor in human umbilical vein endothelial cells. In vivo, AuHQ treatment increased pericyte coverage, modulated tumor leakage while alleviating tumor hypoxia and increased blood perfusion, thereby inducing tumor vascular normalization. Consequently, Au accumulation of the AuHQ group increased by 1.94 fold compared to that in the control group. Furthermore, the antitumor efficacy of radiotherapy was increased by 38% compared to the Au NPs-treated group. Therefore, AuHQ may be a promising nanomedicine for future cancer treatment.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Neoplasias/irrigação sanguínea , Oxiquinolina/química , Radiossensibilizantes/farmacologia , Radioterapia/métodos , Animais , Sobrevivência Celular/efeitos dos fármacos , Feminino , Células Hep G2 , Xenoenxertos , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Camundongos Endogâmicos ICR , Neoplasias/metabolismo , Neoplasias/patologia , Radiossensibilizantes/química , Radioterapia/normas , Espécies Reativas de Oxigênio/metabolismo
11.
J Am Chem Soc ; 143(20): 7732-7739, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-33985332

RESUMO

It is of profound significance with regard to the global energy crisis to develop new techniques and materials that can convert the chemical potential of water into other forms of energy, especially electricity. To address this challenge, we built a new type of energy transduction pathway (humidity gradients → mechanical work → electrical power) using moisture-responsive crystalline materials as the media for energy transduction. Single-crystal data revealed that a flexible zeolitic pyrimidine framework material, ZPF-2-Co, could undergo a reversible structural transformation (ß to α phase) with a large unit cell change upon moisture stimulus. Dynamic water vapor sorption analysis showed a gate-opening effect with a steep uptake at as low as 10% relative humidity (RH). The scalable green synthesis approach and the fast water vapor adsorption-desorption kinetics made ZPF-2-Co an excellent sorbent to harvest water from arid air, as verified by real water-harvesting experiments. Furthermore, we created a gradient distribution strategy to fabricate polymer-hybridized mechanical actuators based on ZPF-2-Co that could perform reversible bending deformation upon a variation of the humidity gradient. This mechanical actuator showed remarkable durability and reusability. Finally, coupling the moisture-responsive actuator with a piezoelectric transducer further converted the mechanical work into electrical power. This work offers a new type of moisture-responsive smart material for energy transduction and provides an in-depth understanding of the responsive mechanism at the molecular level.

12.
J Mol Med (Berl) ; 99(5): 593-617, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33594520

RESUMO

Gene therapy has entered a new era after decades-long efforts, where the recombinant adeno-associated virus (AAV) has stood out as the most potent vector for in vivo gene transfer and demonstrated excellent efficacy and safety profiles in numerous preclinical and clinical studies. Since the first AAV-derived therapeutics Glybera was approved by the European Medicines Agency (EMA) in 2012, there is an increasing number of AAV-based gene augmentation therapies that have been developed and tested for treating incurable genetic diseases. In the subsequent years, the United States Food and Drug Administration (FDA) approved two additional AAV gene therapy products, Luxturna and Zolgensma, to be launched into the market. Recent breakthroughs in genome editing tools and the combined use with AAV vectors have introduced new therapeutic modalities using somatic gene editing strategies. The promising outcomes from preclinical studies have prompted the continuous evolution of AAV-delivered therapeutics and broadened the scope of treatment options for untreatable diseases. Here, we describe the clinical updates of AAV gene therapies and the latest development using AAV to deliver the CRISPR components as gene editing therapeutics. We also discuss the major challenges and safety concerns associated with AAV delivery and CRISPR therapeutics, and highlight the recent achievement and toxicity issues reported from clinical applications.

13.
Biomed Res Int ; 2021: 6648208, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33506026

RESUMO

Bronchopulmonary dysplasia (BPD) is the most common complication of extremely preterm birth. This study was aimed at detecting cytokine and fractional exhaled nitric oxide (FeNO) levels to evaluate their mechanisms and predicted significance for BPD. Preterm infants born at gestational age ≤ 32 weeks were recruited, and clinical data were collected. We detected ten cytokines, including IFN-γ, IL-10, IL-12p70, IL-13, IL-1ß, IL-2, IL-4, IL-6, IL-8, and TNF-α on Days 1-3, Days 7-14, and Days 21-28 after birth by using the Meso Scale Discovery (MSD) technology. The FeNO levels of infants were measured when they met the discharge criteria. A total of 46 preterm infants were enrolled, consisting of 14 infants in BPD group and 32 infants in the control group. The gestational age (27.5 ± 1.3 vs. 29.9 ± 1.3 weeks) and birth weight (1021 ± 261 g vs. 1489 ± 357 g) were lower in the BPD group. The following were high-risk factors for BPD, as determined by multivariate logistic regression analysis: gestational age < 30 weeks, birth weight < 1000 g, PDA, longer mechanical ventilation, and higher FeNO. The cytokines of IL-6 and IL-8 on Days 7-14 and IL-4, IL-6, IL-8, and TNF-α on Days 21-28 were also high-risk factors for BPD. IL-6 contributed to BPD disease severity. Conclusion. The preterm infants with PDA and prolonged mechanical ventilation tended to develop BPD. The IL-6 and IL-8 were significantly increased on Days 7-14 and were high-risk factors for BPD. Moreover, the IL-6 level was associated with BPD disease severity. We speculated that NO was related to BPD via Th2 cell-mediated inflammatory responses such as IL-4 and IL-6. Cytokines might predict the occurrence of BPD.


Assuntos
Displasia Broncopulmonar , Citocinas/sangue , Óxido Nítrico/análise , Biomarcadores/análise , Testes Respiratórios , Displasia Broncopulmonar/sangue , Displasia Broncopulmonar/epidemiologia , Displasia Broncopulmonar/metabolismo , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Fatores de Risco
14.
Transbound Emerg Dis ; 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33406306

RESUMO

Cryptosporidium parvum is a major zoonotic pathogen responsible for outbreaks of severe diarrhoea in humans and calves. Almost all investigations of cryptosporidiosis outbreaks caused by C. parvum have focused on its IIa subtype family in industrialized nations. From December 2018 to April 2019, approximately 200 neonatal calves on a large cattle farm in Hebei Province, China, were diagnosed with watery diarrhoea and over 40 died. To investigate the cause of the outbreak, faecal samples were taken during and after the outbreak from neonatal calves of ≤4 weeks of age (n = 40 and n = 56) and older calves of 4-24 weeks of age (n = 79 and n = 38). A total of 18 faecal samples collected from ill calves at the peak of the outbreak were analysed for four common enteric pathogens using an enzymatic immunoassay (EIA). In addition, 75 samples from neonatal calves were tested for rotavirus by EIA. All samples were analysed for Cryptosporidium spp. using PCR and sequencing techniques. Of the initial 18 samples from sick calves, ten were positive for C. parvum, five for rotavirus, and one for coronavirus. The overall prevalence of rotavirus in neonatal calves was 20.0% (15/75), with no significant differences during and after the outbreak. In contrast, Cryptosporidium parvum infections were significantly higher during the outbreak (60.0%, 24/40) than after the outbreak (30.4%, 17/56; p = .004). Cryptosporidium parvum infection was associated with the presence of watery diarrhoea in neonatal calves (OR = 11.19), while no association was observed between C. bovis infection and diarrhoea. All C. parvum isolates were identified as subtype IIdA20G1. This is one of the few reports of outbreaks of severe diarrhoea caused by C. parvum IId subtypes in calves. More attention should be directed towards the dissemination of C. parvum in China.

15.
Angew Chem Int Ed Engl ; 60(6): 2974-2979, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33210805

RESUMO

Attributed to the unique topological complexity and elegant beauty, Borromean systems are attracting intense attention. However, at present, the construction of Borromean linked organic polymers remains a challenge. To address this formidable challenge, we developed a supramolecular-synthon-driven approach to fabricate Borromean linked organic polymer. The solvothermal condensation reaction of a judiciously selected trigonal pyramidal building block, 1,3,5-Tris(4-aminophenyl)adamantane, with linear dialdehyde building blocks allowed the construction of two rare covalent organic frameworks (COFs) with high crystallinity and robustness. Structure refinement unveiled the successful formation of entangled 2D→2D Borromean arrayed structures. Both the two COFs were of microporosity and thus demonstrated the potentials for gas separation. The successful synthesis of the first two Borromean linked organic polymers paves the avenue to expand the supramolecular-synthon-driven approach to other building blocks and topologies, and broadens the family and scope of COFs.

16.
Angew Chem Int Ed Engl ; 60(26): 14222-14235, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-33090603

RESUMO

Crystalline porous materials (CPMs) have been widely studied over the past few decades due to their well-defined, customizable, and porous structures. However, the limited stability and machinability restrict their particle applications. Recently, a new trend to use hybrid strategies to bridge the gap between CPMs and flexible polymers has emerged as an effective solution to tackle the above issues. Polymers can be either cross-linked within the framework or anchored to the outer surface of the materials, that endow CPMs with polymer features, such as flexibility, ductility, and machinability. Such resulting polymer-tethered CPMs (named as polyCPMs) have demonstrated improved performances in many application scopes such as membrane separation, heterogeneous catalysis and smart response. This minireview highlights state of the art for the hybridization strategies of CPMs with flexible polymers, and provide a perspective on their potential applications and future directions.

17.
Artigo em Inglês | MEDLINE | ID: mdl-33321000

RESUMO

Traditional ozone sensing and removal materials still suffer from high energy consumption and low efficiency. Thus, seeking new ozone-responsive materials with high efficiency and broad working conditions is of great significance. Herein, we first developed covalent organic frameworks (COFs) for smart sensing and efficient removal of ozone. Notably, imine-based COFs possess dramatically fast optical responses (<1 s) to ozone as low as 0.1 ppm under broad working conditions (e.g., in the presence or absence of moisture, room temperature). Moreover, we found that imine-based COFs can also be applied as excellent ozone removers that can efficiently reduce the ozone concentration below the recommended safety limit (<0.1 ppm) for humans. The mechanism for the performance of imine-based COFs was unveiled in-depth by various characterization techniques and analyses. This study not only provides a new type of advanced materials for ozone sensing and removal but also broadens the application scope of COFs.

18.
ACS Appl Mater Interfaces ; 12(46): 51506-51516, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33161706

RESUMO

A high filler content is often needed in polymer composite-based thermoelectric (TE) films to improve their performance. Nevertheless, this often leads to poor processability and poor mechanical performance. Herein, a biomimetic approach is adopted to facilitate the filler content up to 90.5 wt % in free-standing and flexible n-type PVDF/Ag2Se TE films, where PVDF dendricolloids are a solution mixed with Ag2Se nanowires (NWs), followed by filtration. These soft dendric nanoparticles within PVDF dendricolloids have high adhesivity and strong network-building ability, which allows the formation of "grapevine-grape"-like networks with soft dendritic particles and inorganic TE fillers as "grapevine" and "manicure finger grapes", respectively. The maximum power factor of 189.02 µW m-1 K-2 is achieved for a PVDF/Ag2Se mass ratio of 1:9.5 at 300 K. Meanwhile, excellent flexibility with only 15.8% decrease in electrical conductivity after 1000 bending cycles was observed. These properties at such a high filler content are attributed to the long-range grapevine-like network of soft PVDF dendritic particles and entanglement between numerous Ag2Se NWs. This work carves a path to fabricate high-performance free-standing flexible n-type TE composite films as well as other functional polymer composites requiring high inorganic filler loading.

19.
Nanoscale ; 12(41): 21218-21224, 2020 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-33057564

RESUMO

The development of highly efficient and robust biomimetic catalysts is an essential and feasible strategy to overcome the intrinsic drawbacks of natural enzymes. Inspired by the synthetic strategy of covalent organic frameworks, we adopted a covalent-bond-driven strategy to prepare polyoxometalate (POM) based open frameworks (NKPOM-OFs = Nankai University POM-OFs) with abundant Mo[double bond, length as m-dash]O groups that can mimic the active center of sulfite oxidase. Four 2-dimensional (2D) NKPOM-OFs were designed and synthesized via the condensation reaction of linear amino-containing POMs with planar tetra-aldehyde monomers. Benefitting from the high crystallinity, the structures of 2D POM-OFs can be successfully determined from structural simulations. The results unveiled that NKPOM-OFs possessed 2D staggered stacking layered structures with the sql topology. All these NKPOM-OFs exhibited high crystallinity and stability and demonstrated outstanding performance to serve as biomimetic catalysts of sulfite oxidase with good recyclability. Notably, exfoliation of NKPOM-OFs under ultrasonic treatment can significantly boost the catalytic activity with almost two times faster reaction rates. This study not only enriches the facile and versatile synthesis strategy for POM-OFs but also provides new biomimetic platforms for biocatalysis.


Assuntos
Estruturas Metalorgânicas , Compostos de Tungstênio , Biomimética , Catálise , Humanos
20.
Emerg Microbes Infect ; 9(1): 2303-2314, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32990499

RESUMO

ABSTRACT Haemorrhagic fever with renal syndrome (HFRS) following Hantaan virus (HTNV) infection displays variable clinical signs. Humoral responses elicited during HTNV infections are considered important, however, this process remains poorly understood. Herein, we have investigated the phenotype, temporal dynamics, and characteristics of B-cell receptor (BCR) repertoire in an HFRS cohort. The serological profiles were characterized by a lowered expression level of nucleoprotein (NP)-specific antibody in severe cases. Importantly, B-cell subsets were activated and proliferated within the first two weeks of symptom onset and moderate cases reacted more rapidly. BCR analysis in the recovery phase revealed a dramatic increase in the immunoglobulin gene diversity which was more significantly progressed in moderate infections. In severe cases, B-cell-related transcription was lower with inflammatory sets overactivated. Taken together, these data suggest the clinical signs and disease recovery in HFRS patients were positively impacted by rapid and efficacious humoral responses.


Assuntos
Vírus Hantaan/imunologia , Febre Hemorrágica com Síndrome Renal/imunologia , Nucleoproteínas/imunologia , Receptores de Antígenos de Linfócitos B/genética , Adulto , Anticorpos Antivirais/sangue , Anticorpos Antivirais/genética , Linfócitos B/imunologia , China , Regulação para Baixo , Feminino , Febre Hemorrágica com Síndrome Renal/genética , Humanos , Imunidade Humoral , Masculino , Pessoa de Meia-Idade , Análise de Sequência de RNA , Transcrição Genética
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