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1.
Adv Mater ; : e1906722, 2020 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-31957092

RESUMO

The development of Li-S batteries is largely impeded by the growth of Li dendrites and polysulfide shuttling. To solve these two problems simultaneously, herein the study reports a "single atom array mimic" on ultrathin metal organic framework (MOF) nanosheet-based bifunctional separator for achieving the highly safe and long life Li-S batteries. In the designed separator, the periodically arranged cobalt atoms coordinated with oxygen atoms (CoO4 moieties) exposed on the surface of ultrathin MOF nanosheets, "single atom array mimic", can greatly homogenize Li ion flux through the strong Li ion adsorption with O atoms at the interface between anode and separator, leading to stable Li striping/plating. Meantime, at the cathode side, the Co single atom array mimic serves as "traps" to suppress polysulfide shuttling by Lewis acid-base interaction. As a result, the Li-S coin cells with the bifunctional separator exhibit a long cycle life with an ultralow capacity decay of 0.07% per cycle over 600 cycles. Even with a high sulfur loading of 7.8 mg cm-2 , an areal capacity of 5.0 mAh cm-2 can be remained after 200 cycles. Moreover, the assembled Li-S pouch cell displays stable cycling performance under various bending angles, demonstrating the potential for practical applications.

2.
Sci Total Environ ; 703: 135529, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31759722

RESUMO

Planting rice is one of the effective ways to improve saline soils, but the underlying mechanisms are unknown. We studied basic soil properties (including pH, salt content, total nitrogen, etc.) and microbial diversity of the bare soil (salt content >4 g/kg, CK), the Suaeda (Suaeda glauca (Bunge) Bunge) soil (JP), and the soil in which rice (cv. Huaidao 5) grew for one (1Y) and three (3Y) years. The results showed that the soil salinity decreased in the order: CK > JP > 1Y > 3Y. The contents of soil organic matter, total nitrogen, dissolved organic carbon, readily oxidizable carbon, microbial biomass carbon, and particulate organic carbon were higher in 1Y and 3Y compared with CK. The Chao 1 index of soil microbiome diversity was about 1.20 times and 1.49 times higher in the soils after rice compared with JP and CK, respectively. Among the soil microorganisms, the top four abundant phyla were Proteobacteria, Chloroflexi, Bacteriodetes, and Firmicutes. In summary, planting rice decreased soil salinity, and increased the content of nutrients and diversity of microorganisms, thereby improving the saline soil.

3.
Adv Mater ; : e1904249, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31880031

RESUMO

The development of highly efficient photocatalytic systems with rapid photogenerated charge separation and high surface catalytic activity is highly desirable for the storage and conversion of solar energy, yet remains a grand challenge. Herein, a conceptionally new form of atomically dispersed Co-P3 species on CdS nanorods (CoPSA-CdS) is designed and synthesized for achieving unprecedented photocatalytic activity for the dehydrogenation of formic acid (FA) to hydrogen. X-ray absorption near edge structure, X-ray photoelectron spectroscopy, and time-resolved photoluminescence results confirm that the Co-P3 species have a unique electron-rich feature, greatly improving the efficiency of photogenerated charge separation through an interface charge effect. The in situ attenuated total reflection infrared spectra reveal that the Co-P3 species can achieve much better dissociation adsorption of FA and activation of CH bonds than traditional sulfur-coordinated Co single atom-loaded CdS nanorods (CoSSA-CdS). These two new features make CoPSA-CdS exhibit the unprecedented 50-fold higher activity in the photocatalytic dehydrogenation of FA than CoSSA-CdS, and also much better activity than the Ru-, Rh-, Pd-, or Pt-loaded CdS. Besides, CoPSA-CdS also shows the highest mass activity (34309 mmol gCo -1 h-1 ) of Co reported to date. First-principles simulation reveals that the Co-P3 species herein can form an active PHCOO intermediate for enhancing the rate-determining dissociation adsorption of FA.

4.
Adv Mater ; 31(15): e1805833, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30803065

RESUMO

The development of new electrocatalysts with high activity and durability for alcohol oxidation is an emerging need of direct alcohol fuel cells. However, the commonly used Pt-based catalysts still exhibit drawbacks including limited catalytic activity, high overpotential, and severe CO poisoning. Here a general approach is reported for preparing ultrathin PtNiM (M = Rh, Os, and Ir) nanowires (NWs) with excellent anti-CO-poisoning ability and high activity. Owing to their superior nanostructure and optimal electronic interaction, the ultrathin PtNiM NWs show enhanced electrocatalytic performance for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The optimal PtNiRh NWs show mass activity of 1.72 A mg-1 and specific activity of 2.49 mA cm-2 for MOR, which are 3.17 and 2.79 times higher than those of Pt/C. In particular, the onset potentials of PtNiRh NWs for MOR and EOR shift down by about 65 and 85 mV compared with those of Pt/C. Density functional theory calculations further verify their high antipoison properties for MOR and EOR from both an electronic and energetic perspective. Facilitated by the introduction of Rh and Ni, the stable pinning of the Pt 5d band associated with electron-rich and depletion centers solves the dilemma between reactivity and anti-CO poisoning.

5.
Biomacromolecules ; 19(11): 4472-4479, 2018 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-30351917

RESUMO

Self-assembly of site-selective protein-polymer conjugates into stimuli-responsive micelles is interesting owing to their potential biomedical applications, ranging from molecular imaging to drug delivery, but remains a significant challenge. Herein we report a method of site-selective in situ growth-induced self-assembly (SIGS) to synthesize site-specific human serum albumin-poly(2-(diisopropylamino)ethyl methacrylate) (HSA-PDPA) conjugates that can in situ self-assemble into pH-responsive micelles with tunable morphologies. Indocyanine green (ICG) was selectively loaded into the core of sphere-like HSA-PDPA micelles to form pH-responsive fluorescence nanoprobes. The nanoprobes rapidly dissociated into protonated individual unimers at a transition pH of around 6.5, that is the extracellular pH of tumors, which resulted in a sharp fluorescence increase and markedly enhanced cellular uptake. In a tumor-bearing mouse model, they exhibited greatly enhanced tumor fluorescence imaging as compared to ICG alone and pH-nonresponsive nanoprobes. These findings suggest that pH-responsive and site-selective protein-polymer conjugate micelles synthesized by SIGS are promising as a new class of tumor microenvironment-responsive nanocarriers for enhanced tumor imaging and therapy.


Assuntos
Fluorescência , Melanoma/patologia , Metilmetacrilatos/química , Imagem Molecular/métodos , Polímeros/química , Albumina Sérica Humana/química , Microambiente Tumoral , Animais , Feminino , Humanos , Concentração de Íons de Hidrogênio , Processamento de Imagem Assistida por Computador , Verde de Indocianina , Melanoma/diagnóstico por imagem , Melanoma/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Micelas , Espectroscopia de Luz Próxima ao Infravermelho , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
6.
ChemSusChem ; 10(24): 4899-4908, 2017 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-28971593

RESUMO

The fabrication of low-cost and earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) over a broad pH range is attractive. In this work, a facile precursor route is developed to synthesize flower-like nickel phosphide microballs with a diameter of approximately 12 µm. With a controlled phosphorization temperature, flower-like nickel phosphide microballs with different crystalline structures (Ni5 P4 and Ni2 P) were obtained easily. Flower-like Ni5 P4 microballs possessed two advantageous features for enhanced HER: fast vectorial electron transfer path along the building block nanoplates and enhanced inherent catalytic activity of each active site for high-energy (0 0 1) facets. The flower-like Ni5 P4 microballs electrocatalyst thus displayed excellent activity for the HER with a low overpotential (η) of 35.4 mV to reach current densities of 10 mA cm-2 and a small Tafel slope of 48 mV dec-1 in acid solution. In addition, it showed excellent activity in 1 m KOH with η=47 mV at 10 mA cm-2 . DFT studies indicated that the free energy of hydrogen adsorbed on the Ni site of Ni5 P4 was 0.152 eV, which is smaller than that of the Ni site of Ni2 P (0.182 eV). Therefore, flower-like Ni5 P4 microballs exhibited better HER activity than Ni2 P, which is consistent with our HER data. This hierarchical structure with exposed high-energy (0 0 1) facets paves the way to design and synthesize low-cost, high-performance catalysts for the HER.


Assuntos
Técnicas Eletroquímicas/métodos , Nanoestruturas , Níquel/química , Fósforo/química , Catálise , Hidrogênio/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão
7.
Biofabrication ; 8(2): 025001, 2016 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-27078873

RESUMO

Biofabrication is attracting interest as a means to produce nanostructured functional materials because of its operational versatility and full scalability. Materials based on proteins are especially appealing, as the structure and functionality of proteins can be adapted by genetic engineering. Furthermore, strategies and tools for protein production have been developed and refined steadily for more than 30 years. However, protein conformation and therefore activity might be sensitive to production conditions. Here, we have explored whether the downstream strategy influences the structure and biological activities, in vitro and in vivo, of a self-assembling, CD44-targeted protein-only nanoparticle produced in Escherichia coli. This has been performed through the comparative analysis of particles built from soluble protein species or protein versions obtained by in vitro protein extraction from inclusion bodies, through mild, non-denaturing procedures. These methods have been developed recently as a convenient alternative to the use of toxic chaotropic agents for protein resolubilization from protein aggregates. The results indicate that the resulting material shows substantial differences in its physicochemical properties and its biological performance at the systems level, and that its building blocks are sensitive to the particular protein source.


Assuntos
Escherichia coli/metabolismo , Receptores de Hialuronatos/química , Receptores de Hialuronatos/metabolismo , Nanopartículas/química , Escherichia coli/genética , Engenharia Genética , Receptores de Hialuronatos/genética , Corpos de Inclusão/química , Corpos de Inclusão/genética , Corpos de Inclusão/metabolismo , Microbiologia Industrial , Nanopartículas/metabolismo , Conformação Proteica , Solubilidade
8.
Nanomedicine ; 12(5): 1241-51, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26949165

RESUMO

A single chain polypeptide containing the low density lipoprotein receptor (LDLR) ligand Seq-1 with blood-brain barrier (BBB) crossing activity has been successfully modified by conventional genetic engineering to self-assemble into stable protein-only nanoparticles of 30nm. The nanoparticulate presentation dramatically enhances in vitro, LDLR-dependent cell penetrability compared to the parental monomeric version, but the assembled protein does not show any enhanced brain targeting upon systemic administration. While the presentation of protein drugs in form of nanoparticles is in general advantageous regarding correct biodistribution, this principle might not apply to brain targeting that is hampered by particular bio-physical barriers. Irrespective of this fact, which is highly relevant to the nanomedicine of central nervous system, engineering the cationic character of defined protein stretches is revealed here as a promising and generic approach to promote the controlled oligomerization of biologically active protein species as still functional, regular nanoparticles.


Assuntos
Barreira Hematoencefálica , Sistemas de Liberação de Medicamentos , Nanopartículas , Peptídeos , Humanos , Receptores de LDL , Distribuição Tecidual
9.
Philos Trans A Math Phys Eng Sci ; 374(2062)2016 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-26809577

RESUMO

The 5G network is anticipated to meet the challenging requirements of mobile traffic in the 2020s, which are characterized by super high data rate, low latency, high mobility, high energy efficiency and high traffic density. This paper provides an overview of China Mobile's 5G vision and potential solutions. Three key characteristics of 5G are analysed, i.e. super fast, soft and green. The main 5G R&D themes are further elaborated, which include five fundamental rethinkings of the traditional design methodologies. The 5G network design considerations are also discussed, with cloud radio access network, ultra-dense network, software defined network and network function virtualization examined as key potential solutions towards a green and soft 5G network. The paradigm shift to user-centric network operation from the traditional cell-centric operation is also investigated, where the decoupled downlink and uplink, control and data, and adaptive multiple connections provide sufficient means to achieve a user-centric 5G network with 'no more cells'. The software defined air interface is investigated under a uniform framework and can adaptively adapt the parameters to well satisfy various requirements in different 5G scenarios.

10.
Biotechnol Adv ; 33(2): 277-87, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25698504

RESUMO

The increasing incidence of diseases affecting the central nervous system (CNS) demands the urgent development of efficient drugs. While many of these medicines are already available, the Blood Brain Barrier and to a lesser extent, the Blood Spinal Cord Barrier pose physical and biological limitations to their diffusion to reach target tissues. Therefore, efforts are needed not only to address drug development but specially to design suitable vehicles for delivery into the CNS through systemic administration. In the context of the functional and structural versatility of proteins, recent advances in their biological fabrication and a better comprehension of the physiology of the CNS offer a plethora of opportunities for the construction and tailoring of plain nanoconjugates and of more complex nanosized vehicles able to cross these barriers. We revise here how the engineering of functional proteins offers drug delivery tools for specific CNS diseases and more transversally, how proteins can be engineered into smart nanoparticles or 'artificial viruses' to afford therapeutic requirements through alternative administration routes.


Assuntos
Doenças do Sistema Nervoso Central/tratamento farmacológico , Sistema Nervoso Central/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Técnicas de Transferência de Genes , Barreira Hematoencefálica/efeitos dos fármacos , Sistema Nervoso Central/patologia , Doenças do Sistema Nervoso Central/patologia , Humanos , Nanomedicina , Nanopartículas/química , Nanopartículas/uso terapêutico , Ácidos Nucleicos/uso terapêutico
11.
Methods Mol Biol ; 1258: 1-24, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25447856

RESUMO

Proteins are synthesized in heterologous systems because of the impossibility to obtain satisfactory yields from natural sources. The production of soluble and functional recombinant proteins is among the main goals in the biotechnological field. In this context, it is important to point out that under stress conditions, protein folding machinery is saturated and this promotes protein misfolding and, consequently, protein aggregation. Thus, the selection of the optimal expression organism and the most appropriate growth conditions to minimize the formation of insoluble proteins should be done according to the protein characteristics and downstream requirements. Escherichia coli is the most popular recombinant protein expression system despite the great development achieved so far by eukaryotic expression systems. Besides, other prokaryotic expression systems, such as lactic acid bacteria and psychrophilic bacteria, are gaining interest in this field. However, it is worth mentioning that prokaryotic expression system poses, in many cases, severe restrictions for a successful heterologous protein production. Thus, eukaryotic systems such as mammalian cells, insect cells, yeast, filamentous fungus, and microalgae are an interesting alternative for the production of these difficult-to-express proteins.


Assuntos
Proteínas Recombinantes/isolamento & purificação , Animais , Bactérias/genética , Bactérias/metabolismo , Biotecnologia/métodos , Eucariotos/genética , Eucariotos/metabolismo , Humanos , Dobramento de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
12.
ChemSusChem ; 7(9): 2427-31, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24961677

RESUMO

A glucose/air biofuel cell (BFC) that can convert both chemical and light energy into electricity is described. Polyterthiophene (pTTh), a photoresponsive conducting polymer, serves as cathode and catalyzes the reduction of oxygen. Taking advantage of the good environmental stability and exceptional optical properties of pTTh, the assembled BFC exhibits excellent stability and a fast photoresponse with an open-circuit voltage (V(oc)) of 0.50 V and a maximum power output density (P(max)) of 23.65 µW cm(-2) upon illumination by visible light of 10 mW cm(-2) , which is an enhancement of ca. 22 times as compared to P(max) in the dark. Additionally, we propose a possible mechanism for this enhancement. Fabricating a BFC in this manner provides an energy conversion model that offers high efficiency at low cost, paving an avenue for practical solar energy conversion on a large scale.


Assuntos
Ar , Fontes de Energia Bioelétrica , Glucose/química , Luz , Catálise , Eletroquímica
13.
ACS Nano ; 8(5): 4166-76, 2014 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-24708510

RESUMO

The fully de novo design of protein building blocks for self-assembling as functional nanoparticles is a challenging task in emerging nanomedicines, which urgently demand novel, versatile, and biologically safe vehicles for imaging, drug delivery, and gene therapy. While the use of viruses and virus-like particles is limited by severe constraints, the generation of protein-only nanocarriers is progressively reachable by the engineering of protein-protein interactions, resulting in self-assembling functional building blocks. In particular, end-terminal cationic peptides drive the organization of structurally diverse protein species as regular nanosized oligomers, offering promise in the rational engineering of protein self-assembling. However, the in vivo stability of these constructs, being a critical issue for their medical applicability, needs to be assessed. We have explored here if the cross-molecular contacts between protein monomers, generated by end-terminal cationic peptides and oligohistidine tags, are stable enough for the resulting nanoparticles to overcome biological barriers in assembled form. The analyses of renal clearance and biodistribution of several tagged modular proteins reveal long-term architectonic stability, allowing systemic circulation and tissue targeting in form of nanoparticulate material. This observation fully supports the value of the engineered of protein building blocks addressed to the biofabrication of smart, robust, and multifunctional nanoparticles with medical applicability that mimic structure and functional capabilities of viral capsids.


Assuntos
Nanomedicina/métodos , Nanopartículas/química , Proteínas/química , Animais , Capsídeo/química , Cátions , Sistemas de Liberação de Medicamentos , Feminino , Engenharia Genética , Proteínas de Fluorescência Verde/química , Histidina/química , Humanos , Ligações de Hidrogênio , Rim/metabolismo , Ligantes , Camundongos , Camundongos Nus , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Peptídeos/química , Ligação Proteica , Mapeamento de Interação de Proteínas , Eletricidade Estática
14.
Nanoscale ; 6(1): 145-50, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24202086

RESUMO

We have fabricated a BiOBr film for the first time through water-air interfacial self-assembly, which is a green, easily processable and environmentally friendly strategy. Moreover, an ultraviolet photodetector based on the BiOBr film exhibited excellent stability and a fast response time.

15.
Chem Commun (Camb) ; 49(43): 4953-5, 2013 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-23609759

RESUMO

A novel and facile method is developed to prepare an Ag@AgCl film which exhibits high photocatalytic activity under visible light irradiation. In addition, it can also be used to fabricate a photodetector that possesses a fast response time and good photocurrent reproducibility.

16.
J Nat Med ; 67(1): 222-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22476613

RESUMO

Secoisolariciresinol (SECO) is a natural lignan-type phytoestrogen constituent mainly found in flaxseed. It can be metabolized in vivo to mammalian lignans of enterodiol and enterolactone, which have been proven to be effective in relieving menopausal syndrome. Depression is one of the most common symptoms of menopausal syndrome, and is currently treated with estrogen replacement and antidepressant therapy. However, due to the serious side-effects of such agents, there are urgent needs for safer and more tolerable treatments. In this paper, using two classical depression models, the forced swimming test and the tail suspension test, we report the antidepressant effect of SECO on ovariectomized (OVX) mice by intragastric administration for 14 consecutive days at doses of 5, 10 and 20 mg/kg. The results showed that SECO (10 mg/kg) treatment could significantly reduce the duration of immobility of OVX mice in these two models compared with the control group (OVX mice + vehicle), which was similar to the positive control imipramine. In addition, SECO treatment could substantially increase brain monoamine (norepinephrine and dopamine) levels in OVX mice. The present studies showed that SECO can reverse depressive-like behavior and exhibit monoamine-enhancing effects.


Assuntos
Antidepressivos/uso terapêutico , Butileno Glicóis/uso terapêutico , Linho/química , Lignanas/uso terapêutico , Fitoestrógenos/uso terapêutico , Animais , Antidepressivos/química , Comportamento Animal/efeitos dos fármacos , Butileno Glicóis/química , Depressão/tratamento farmacológico , Feminino , Lignanas/química , Camundongos , Ovariectomia , Fitoestrógenos/química
17.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 27(6): 637-40, 2011 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-21651864

RESUMO

AIM: To clone a novel swine gene P58(IPK)[58-kDa(inhibitor of protein kinase) protein] and prepare its polyclonal antibody for further research of influenza and host interaction. METHODS: The swine P58(IPK); gene was first identified in silico through homology searching in the swine EST database. Then this gene was amplified by reverse transcription polymerase chain reaction (RT-PCR). The cDNA of the gene contained the complete open reading frame(ORF) of 1 518 bp, and encoded 505 amino acid residues (Accession No.HQ287801). The gene was first analyzed using bioinformatics methods. Then P58(IPK) was cloned into a prokaryotic expression vector pET-32a to construct a recombinant plasmid named as pET-P58(IPK). The fusion protein his-P58(IPK) was expressed in E.coli BL21 and purified using a his-tag protein purification column. Subsequently rabbits were immunized with the purified protein. RESULTS: Specific polyclonal antibody against the fusion protein his-P58(IPK) was obtained. The activity of the antibody was determined through double-immunodiffusion test. The titer of the antibody was 1:20 000 as shown by ELISA. specifically recognized the protein P58(IPK) by Western blot and immunofluorescence assay. CONCLUSION: The novel swine gene P58(IPK) has been successfully cloned and its polyclonal antibody has been prepared.


Assuntos
Anticorpos/isolamento & purificação , Clonagem Molecular/métodos , Proteínas de Choque Térmico HSP40/isolamento & purificação , Imunização , Proteínas Recombinantes/isolamento & purificação , Animais , Anticorpos/genética , Anticorpos/imunologia , Escherichia coli/genética , Escherichia coli/imunologia , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos , Proteínas de Choque Térmico HSP40/genética , Proteínas de Choque Térmico HSP40/metabolismo , Plasmídeos , Coelhos , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Suínos
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