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1.
J Colloid Interface Sci ; 606(Pt 2): 961-970, 2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34487943

RESUMO

The usage of single-use face masks (SFMs) has increased since the outbreak of the coronavirus pandemic. However, non-degradability and mismanagement of SFMs have raised serious environmental concerns. Moreover, both melt-blown and nanofiber-based mask filters inevitably suffer from poor filtration performance, like a continuous decrease in the removal efficiency for particulate matter (PM) and weak breathability. Herein, we report a new method to create biodegradable and reusable fibrous mask filters. The filter consists of a true nanoscale bio-based poly(lactic acid) (PLA) fiber (an average size of 37 ± 4 nm) that is fabricated via electrospinning of an extremely dilute solution. Furthermore, we designed a multiscale structure with integrated features, such as low basis weight (0.91 g m-2), small pore size (0.73 µm), and high porosity (91.72%), formed by electrospinning deposition of true nanoscale fibers on large pore of 3D scaffold nanofiber membranes. The resultant mask filter exhibited a high filtration efficiency (PM0.3-99.996%) and low pressure drop (104 Pa) superior to the commercial N95 filter. Importantly, this filter has a durable filtering efficiency for PM and natural biodegradability based on PLA. Therefore, this study offers an innovative strategy for the preparation of PLA nanofibers and provides a new design for high-performance nanofiber filters.

2.
J Colloid Interface Sci ; 607(Pt 1): 711-719, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34530191

RESUMO

Indoor air quality (IAQ) has assumed new significance given the extensive amount of time spent indoor due to the coronavirus pandemic and particulate matter (PM) pollution. Accordingly, the development of window air filters to effectively intercept PM from outdoor air under natural ventilation conditions is an important research topic. However, most existing filters inevitably suffer from the compromise among filtration capability, transparency, and air permeability. In this study, we fabricate a high-performance transparent air filter to improve IAQ via natural ventilation. polyvinylidene fluoride (PVDF) superfine nanofibers of size 20-35 nm are prepared using extremely dilute solution electrospinning; a multi-scale nanofiber structure is then designed. By adjusting the ratio of PVDF superfine nanofibers (SNs) to PVDF coarse fibers (CNs), we balance the structure-performance relationship. Benefiting from the multiscale structural features that include a small pore size (0.72 µm) and high porosity (92.22%), the resulting filters exhibit excellent performance including high interception efficiency (99.92%) for PM0.3, low air resistance (69 Pa), high transparency (∼80%) and stable filtration after 100 h of UV irradiation. This work describes a new strategy for the fabrication of nanofibers with true-nanoscale diameters and the design of high-performance air filters.

3.
Immunogenetics ; 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34406419

RESUMO

Artemis (DCLRE1C) is involved in opening recombination-activating gene (RAG1/RAG2)-generated hairpins during V(D)J recombination, an essential process for the differentiation and maturation of T and B cells. Here, we reported a case of 5-month-old boy with recurrent respiratory infections, disseminated Bacille Calmette-Guérin (BCG) infection, generalized erythroderma, hepatosplenomegaly, lymphadenopathy, eosinophillia and failure to thrive, symptoms often observed in Omenn syndrome. Genetic analysis revealed compound heterozygous mutations of the DCLRE1C gene, including deletions of exons 1 and 2, and a c. 352G>T (p. G118X) nonsense mutation in exon 5. Flow cytometry analysis of the patient PBMCs indicated a TlowB-NK+ immunophenotype. Short tandem repeat (STR) analysis confirmed transplacental maternal lymphocytes engraftment in circulating blood of the patient. Collectively, we reported a patient showing atypical immunophenotypic and typical clinical presentations of Severe Combined Immunodeficiency (SCID) with Graft Versus Host Disease (GVHD) in the context of compound heterozygous mutations of the DCLRE1C gene. This study adds to the ever-growing knowledge on the broad immunological and clinical spectrum associated with DCLRE1C mutations.

4.
Molecules ; 26(16)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34443582

RESUMO

Biological imaging is an essential means of disease diagnosis. However, semiconductor quantum dots that are used in bioimaging applications comprise toxic metal elements that are nonbiodegradable, causing serious environmental problems. Herein, we developed a novel ecofriendly solvothermal method that uses ethanol as a solvent and doping with chlorine atoms to prepare highly fluorescent graphene quantum dots (GQDs) from seaweed. The GQDs doped with chlorine atoms exhibit high-intensity white fluorescence. Thus, their preliminary application in bioimaging has been confirmed. In addition, clear cell imaging could be performed at an excitation wavelength of 633 nm.


Assuntos
Cloro/química , Grafite/química , Imagem Molecular/métodos , Pontos Quânticos/química , Alga Marinha/química , Linhagem Celular , Fluorescência
5.
Langmuir ; 2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34042453

RESUMO

Acid-responsive nonaqueous (glycerol in n-decane) Pickering emulsions were prepared using preferentially oil-wetted dynamic covalent silica (SiO2-pDB) nanoparticles as the Pickering emulsifiers. The acid-responsive Pickering emulsifier SiO2-pDB was prepared based on a Schiff base reaction between amino silica (SiO2-NH2) and p-decanoxybenzaldehyde (pDBA). The formation of SiO2-pDB was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis. The preferentially oil-wetted character of SiO2-pDB was indicated by contact angle measurement. Stable nonaqueous Pickering emulsions were prepared using preferentially oil-wetted SiO2-pDB as the Pickering emulsifier. However, after adjusting the nonaqueous Pickering emulsions to an acidic environment, complete phase separation occurred. In the acidic environment, preferentially oil-wetted SiO2-pDB decomposed into hydrophilic SiO2-NH2 and hydrophobic pDBA due to the decomposition of the dynamic imine bond in the SiO2-pDB. Then, the hydrophilic SiO2-NH2 and hydrophobic pDBA desorbed from the two-phase interface, resulting in complete phase separation of the initially stable nonaqueous Pickering emulsions. The acid-responsive nonaqueous Pickering emulsions show great potential in application in water sensitive systems, such as oil-based drilling fluids.

6.
J Colloid Interface Sci ; 584: 164-173, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33069016

RESUMO

Antibacterial textiles, which effectively inhibit bacterial breeding and resist pathogenic diseases, have wide applications in medicine, hygiene, and related fields. However, traditional antibacterial textiles exhibit significant limitations, such as poor antibacterial durability and contamination during preparation. In this work, nanofiber yarn loaded with a high-efficiency antibacterial agent was prepared using electrospinning technology. Polyethyleneimine (PEI) was introduced as a solubilizing material to functionalize graphene oxide (GO) to form GO-PEI composites. A facile microwave heating method was used to synthesize GO-PEI and silver nanoparticles (AgNPs). A multi-needle conjugated electrospinning device was used to blend the nanofibers with the GO-PEI-Ag composite to form a nanofiber core-spun yarn. The antibacterial agent was firmly fixed on the fiber to prevent easy removal. A uniformly oriented yarn structure and internal morphology were observed, and the antibacterial activity of the fabric was measured. The antibacterial rate of the fabric was over 99.99%for both Escherichia coli and Staphylococcus aureus. After ten washes, the antibacterial rate remained above 99.99%. Thus, nanofiber fabric from electrospinning displays high antibacterial activity and excellent durability, thereby providing a feasible methodology for future production of antibacterial textiles.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Nanofibras , Antibacterianos/farmacologia , Grafite , Prata/farmacologia , Têxteis
7.
Polymers (Basel) ; 12(4)2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32268559

RESUMO

Waterproof-breathable (WB) materials with outstanding waterproofness, breathability, and mechanical performance are critical in diverse consumer applications. Electrospun nanofibrous membranes with thin fiber diameters, small pore sizes, and high porosity have attracted significant attention in the WB fabric field. Hot-press treatment technology can induce the formation of inter-fiber fusion structures and hence improve the waterproofness and mechanical performance. By combining electrospinning and hot-press treatment technology, polyurethane/fluorinated polyurethane/thermoplastic polyurethane/alkylsilane-functionalized graphene (PU/FPU/TPU/FG) nanofiber WB fabric was fabricated. Subsequently, the morphologies, porous structure, hydrostatic pressure, water vapor transmission rate (WVTR), and stress-strain behavior of the nanofiber WB fabric were systematically investigated. The introduction of the hydrophobic FG sheet structure and the formation of the inter-fiber fusion structure greatly improved not only the waterproofness but also the mechanical performance of the nanofiber WB fabric. The optimized PU/FPU/TPU-50/FG-1.5 WB fabric exhibited an excellent comprehensive performance: a high hydrostatic pressure of 80.4 kPa, a modest WVTR of 7.6 kg m-2 d-1, and a robust tensile stress of 127.59 MPa, which could be used to achieve various applications. This work not only highlights the preparation of materials, but also provides a high-performance nanofiber WB fabric with huge potential application prospects in various fields.

8.
J Colloid Interface Sci ; 561: 93-103, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31812870

RESUMO

Highly sensitive wearable textile pressure sensors represent the key components of smart textiles and personalized electronics, with potential applications in biomedical monitoring, electronic skin, and human-machine interfacing. Here, we present a simple and low-cost strategy to fabricate highly sensitive wearable textile pressure sensors for non-invasive human motion and physiological signal monitoring and the detection of dynamic tactile stimuli. The wearable textile sensor was woven using a one-dimensional (1D) weavable core-sheath nanofiber yarn, which was obtained by coating a Ni-coated cotton yarn electrode with carbon nanotube (CNT)-embedded polyurethane (PU) nanofibers using a simple electrospinning technique. In our design, the three-dimensional elastic porous nanofiber structure of the force-sensing layer and hierarchical fiber-bundled structure of the conductive Ni-coated electrode provide the sensor with a relatively large surface area, and a sufficient surface roughness and elasticity. This leads to rapid and sharp increases in the contact area under stimuli with low external pressure. As a result, the textile pressure sensor exhibits the advantages of a high sensitivity (16.52 N-1), wide sensing range (0.003-5 N), and short response time (~0.03 s). Owing to these merits, our textile-based sensor can be directly attached to the skin as usual and conformally fit the shape deformations of the body's complex flexible curved surfaces. This contributes to the reliable real-time monitoring of human movements, ranging from subtle physiological signals to vigorous movements. Moreover, a large-area textile sensing matrix is successfully fabricated for tactile mapping of spatial pressure by being worn on the surface of wrist, highlighting the tremendous potential for applications in smart textiles and wearable electronics.


Assuntos
Técnicas Biossensoriais , Movimento , Nanofibras/química , Nanotubos de Carbono/química , Poliuretanos/química , Têxteis , Dispositivos Eletrônicos Vestíveis , Condutividade Elétrica , Humanos , Porosidade , Pressão
9.
J Colloid Interface Sci ; 557: 318-327, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31525669

RESUMO

Pollution by atmospheric particulate matter (PM) is a serious threat to human health, and traditional window screens are unable to intercept fine particles. Therefore, it is urgent to develop anti-haze window screens to effectively protect the public. We prepared a polyurethane/silicon nitride (PU/Si3N4) electret nanofiber membrane with a minimum diameter (350 nm) and narrower diameter distribution than those of PU-Boehmite, PU-SiO2, and PU-TiO2 membranes by electrospinning. The PU-Si3N4 fiber membrane has good mechanical properties with stress of 18.05 MPa and strain of 170%. Moreover, PU/Si3N4 exhibits a maximum current peak (2.63 pA) at 90 °C. Importantly, PU/Si3N4 membranes applied to window screens still maintain high filtration efficiency (79.36%) and low resistance (25 Pa) to air flow at a low areal density of 1.22 g/m2. Furthermore, they show good light transmittance (40%) and air permeability (46.42 mm s-1). Therefore, PU/Si3N4 electret nanofiber window screens have broad application prospects.

10.
Epidemiol Infect ; 147: e192, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-31364532

RESUMO

Paediatric Mycoplasma pneumoniae pneumonia (MPP) is a major cause of community-acquired pneumonia in China. Data on epidemiology of paediatric MPP from China are little known. This study retrospectively collected data from June 2006 to June 2016 in Beijing Children's Hospital, Capital Medical University of North China and aims to explore the epidemiological features of paediatric MPP and severe MPP (SMPP) in North China during the past 10 years. A total of 27 498 paediatric patients with pneumonia were enrolled. Among them, 37.5% of paediatric patients had MPP. In this area, an epidemic took place every 2-3 years at the peak, and the positive rate of MPP increased during these peak years over time. The peak age of MPP was between the ages of 6 and 10 years, accounting for 75.2%, significantly more compared with other age groups (χ2 = 1384.1, P < 0.0001). The epidemics peaked in September, October and November (χ2 = 904.9, P < 0.0001). Additionally, 13.0% of MPP paediatric patients were SMPP, but over time, the rate of SMPP increased, reaching 42.6% in 2016. The mean age of paediatric patients with SMPP (6.7 ± 3.0 years old) was younger than that of patients with non-SMPP (7.4 ± 3.2 years old) (t = 3.60, P = 0.0001). The prevalence of MPP and SMPP is common in China, especially in children from 6 to 10 years old. Paediatric patients with SMPP tend to be younger than those with non-SMPP. MPP outbreaks occur every 2-3 years in North China. September, October and November are the peak months, unlike in South China. Understanding the epidemiological characteristics of paediatric MPP can contribute to timely treatment and diagnosis, and may improve the prognosis of children with SMPP.


Assuntos
Infecções Comunitárias Adquiridas/epidemiologia , Epidemias , Pneumonia por Mycoplasma/epidemiologia , Adolescente , Fatores Etários , Criança , Pré-Escolar , China/epidemiologia , Feminino , Hospitais Pediátricos , Hospitais Universitários , Humanos , Lactente , Recém-Nascido , Masculino , Prevalência , Estudos Retrospectivos , Estações do Ano
11.
Sensors (Basel) ; 19(11)2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31195614

RESUMO

Non-planar sensor arrays are used to determine solar orientation based on the orientation matrix formed by orientation vectors of the sensor planes. Solar panels or existing photodiodes can be directly used without increasing the size or mass of the spacecraft. However, a limiting factor for the improvement of the accuracy of orientation lies with the lack of an assessment-based approach. A formulation was developed for the supremum (i.e., the least upper bound) of orientation error of an arbitrary orientation matrix in terms of its influencing factors. The new formulation offers a way to evaluate the supremum of orientation error considering interference with finite energy and interference with infinite energy but finite average energy. For a given non-planar sensor array, a sub-matrix of the full orientation matrix would reach the optimal accuracy of orientation if its supremum of orientation error is the least. Principles for designing an optimal sensor array relate to the configuration of the orientation matrix, which can be pre-determined for a given number of sensors. Simulations and field experiment tested and validated the methods, showing that our sensor array optimization method outperforms the existing methods, while providing a way of assessment and optimization.

12.
Org Biomol Chem ; 17(17): 4311-4316, 2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-30972387

RESUMO

A novel DMSO-involved cascade reaction of stabilized sulfonium salts has been established for direct construction of polyfunctional furans. This one-pot sequential reaction involving in situ generated α-methylene sulfonium salts was followed by [4 + 1] annulation with sulfur ylides. Notably, DMSO plays a very important role in this transformation, not only as a solvent but also as one carbon source.

13.
J Org Chem ; 84(5): 2962-2968, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30747536

RESUMO

A trifluoroacetic acid (TFA)-mediated cascade oxidation/1,3-dipolar cycloaddition reaction of stabilized pyridinium salts with dimethyl sulfoxide (DMSO) has been developed in the presence of K2S2O8 and trimethylethylenediamine (TMEDA). In this transition-metal-free reaction, DMSO acts as a one-carbon source, thus providing a convenient method for the efficient and direct synthesis of various indolizine derivatives.

14.
Pediatr Allergy Immunol ; 30(3): 378-386, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30716179

RESUMO

BACKGROUND: Chronic granulomatous disease (CGD) is a rare disease in China, and very little large-scale studies have been conducted to date. We aimed to investigate the clinical and genetic features of CGD in Chinese pediatric patients. METHODS: Pediatric patients with CGD from Beijing Children's Hospital, Capital Medical University, China, were enrolled from January 2006 to December 2016. RESULTS: A total of 159 pediatric patients with CGD were enrolled. The median age of clinical onset was 1.4 months, and 73% (116/159) had clinical onset symptoms before the 1 year of age. The most common site of invasion was the lungs. The lymph nodes, liver, and skin were more frequently invaded in X-linked (XL) CGD patients than in autosomal recessive (AR) CGD patients (P < 0.05). Approximately 64% (92/144) of the pediatric patients suffered from abnormal response to BCG vaccination. The most frequent pathogens were Aspergillus and Mycobacterium tuberculosis. Gene analysis indicated that 132 cases (89%, 132/147) harbored CYBB pathogenic variants, 7 (5%, 7/147) carried CYBA pathogenic variants, 4 (3%, 4/147) had NCF1 pathogenic variants, and 4 (3%, 4/147) had NCF2 pathogenic variants. The overall mortality rate in this study was 43%, particularly the patients were males, with CYBB mutant and did not receive HSCT treatment. CONCLUSIONS: Chronic granulomatous disease is a rare disease affecting Chinese children; however, it is often diagnosed at a later age, and thus, the mortality rate is relatively high. The prevalence and the severity of disease in XL-CGD are higher than AR-CGD.


Assuntos
Doença Granulomatosa Crônica/diagnóstico , NADPH Oxidases/genética , Adolescente , Anti-Infecciosos/uso terapêutico , Grupo com Ancestrais do Continente Asiático/genética , Criança , Pré-Escolar , China , Feminino , Testes Genéticos/métodos , Doença Granulomatosa Crônica/genética , Doença Granulomatosa Crônica/mortalidade , Humanos , Lactente , Recém-Nascido , Masculino , Mutação , Estudos Retrospectivos
15.
Materials (Basel) ; 12(2)2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30654431

RESUMO

One-dimensional, flexible yarn-shaped supercapacitors for woven cloth have the potential for use in different kinds of wearable devices. Nevertheless, the challenge that supercapacitors face is low energy density. In this paper, we present a low-cost and large-scale manufacturing method to construct a supercapacitor yarn with high power and high energy density. To construct the novel and flexible poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)⁻polyacrylonitrile (PDEOT: PSS-PAN)/Ni cotton (PNF/NiC) capacitor yarn, an electrospinning technique was initially used to wrap the polyacrylonitrile (PAN) nanofibers around the core Ni-coated yarn. The PEDOT: PSS⁻PAN nanofiber composite electrode was created using in situ deposition and H3PO4/PVA was used as a gel electrolyte. This electrode material has a yarn/nanofiber/PEDOT: PSS nanoparticle hierarchical structure, providing a high specific area and enhanced pseudocapacitance. The electrode demonstrated a high volumetric capacitance of 26.88 F·cm-3 (at 0.08 A·cm-3), an energy density of 9.56 mWh·cm-3, and a power density of 830 mW·cm-3. In addition, the PNF/NiC capacitor yarns are lightweight, highly flexible, resistant to bending fatigue, can be connected in series or parallel, and may be suitable for a variety of wearable electronic products.

16.
Biomed Res Int ; 2019: 8207056, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31976328

RESUMO

Mutant p53 (R248Q) induces doxorubicin (ADM) resistance in hepatocellular carcinoma (HCC). Dihydroartemisinin (DHA) can synergistically enhance anticancer effect of many chemotherapeutic agents. However, whether DHA could increase therapeutic efficacy of ADM in p53 (R248Q)-expressing HCC cells remains unknown. In the present study, we established mutant p53 (R248Q)-expressing Hep3B cells to study the effect and mechanism of DHA on ADM resistance and the synergistic effect of DHA with ADM. We found that P-gp was highly expressed in p53 (R248Q)-expressing Hep3B cells. As a result, cells expressing p53 (R248Q) displayed higher cell viability and lower cell apoptosis level upon ADM treatment. Meanwhile, phosphorylation levels of ERK1/2 and p65 were elevated in p53 (R248Q)-expressing Hep3B cells. However, combination of DHA and ADM treatment decreased cell viability and elevated cell apoptosis level in p53 (R248Q)-expressing Hep3B cells. Molecular dynamics simulations showed that DHA had the potential to bind with mutant p53 (R248Q) protein. Furthermore, DHA treatment decreased P-gp expression and inhibited phosphorylation levels of ERK1/2 and p65 in p53 (R248Q)-expressing Hep3B cells. Finally, DHA treatment could significantly reduce ADM efflux in p53 (R248Q)-expressing cells. Our results indicate that DHA could decrease P-gp expression via inhibiting the p53 (R248Q)-ERK1/2-NF-κB signaling pathway, which eventually confers sensitization of p53 (R248Q)-expressing HCC cells to ADM. Our study provides evidence for the potential application of DHA and ADM combination in treatment of mutant p53 (R248Q)-harbored HCC.


Assuntos
Antimaláricos/farmacologia , Antineoplásicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Doxorrubicina/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Apoptose/efeitos dos fármacos , Artemisininas , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , NF-kappa B/metabolismo , Transdução de Sinais/efeitos dos fármacos
17.
Adv Mater ; 31(7): e1805921, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30589117

RESUMO

Together with the evolution of digital health care, the wearable electronics field has evolved rapidly during the past few years and is expected to be expanded even further within the first few years of the next decade. As the next stage of wearables is predicted to move toward integrated wearables, nanomaterials and nanocomposites are in the spotlight of the search for novel concepts for integration. In addition, the conversion of current devices and attachment-based wearables into integrated technology may involve a significant size reduction while retaining their functional capabilities. Nanomaterial-based wearable sensors have already marked their presence with a significant distinction while nanomaterial-based wearable actuators are still at their embryonic stage. This review looks into the contribution of nanomaterials and nanocomposites to wearable technology with a focus on wearable sensors and actuators.


Assuntos
Nanoestruturas , Dispositivos Eletrônicos Vestíveis , Acelerometria/instrumentação , Sistemas de Liberação de Medicamentos/instrumentação , Humanos , Monitorização Fisiológica/instrumentação
18.
Analyst ; 143(17): 4136-4146, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-30065973

RESUMO

We report an innovative amperometric hydrogen sensor that addresses current primary issues (i.e. signal drift, low selectivity and speed) in continuous and real-time gas sensing. Utilizing the unique properties and redox reactions of hydrogen in the ionic liquids (ILs), 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [Bmpy][NTf2] and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [Bmim][NTf2], we demonstrate the real-time and continuous sensing of hydrogen with high sensitivity, selectivity and repeatability in both anaerobic and aerobic conditions using simple constant potential amperometry. The varying adsorption of hydrogen at the IL-electrode interface in different ILs is shown to allow tuning of the sensitivity of the sensor. Taking advantage of oxygen in ambient conditions, we demonstrate that the unique chemical reaction of the analyte with the oxygen enables selective quantification of hydrogen in an ambient environment. A sensor calibration based on a kinetics analysis (i.e. the change of the rate of current signal (ΔI/Δt1/2)) rather than an equilibrium analysis was demonstrated to allow fast and quantitative analysis of hydrogen concentration. The ionic liquid hydrogen sensor exhibits high sensitivity, selectivity, speed, accuracy, repeatability and stability. Together with the miniaturization and affordability of amperometric sensor readout electronics, the IL-based electrochemical gas sensor is expected to enable area-wide sensing instead of point measurements for environmental, health and occupational safety applications.

19.
J Org Chem ; 83(16): 9156-9165, 2018 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-29877082

RESUMO

An interesting σ-bond insertion/benzannulation reaction for the synthesis of polysubstituted naphthalene derivatives has been developed from readily accessible ketones, arynes, and alkynoates. This practical and transition-metal-free method provides a novel route to diverse naphthalenes through a substrate-controlled rearrangement reaction with the cleavage of C-C bonds.

20.
Mater Sci Eng C Mater Biol Appl ; 84: 195-207, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29519429

RESUMO

In bone tissue engineering, the fabrication of a scaffold with a hierarchical architecture, excellent mechanical properties, and good biocompatibility remains a challenge. Here, a solution of polylactic acid (PLA) and Tussah silk fibroin (TSF) was electrospun into nanofiber yarns and woven into multilayer fabrics. Then, composite scaffolds were obtained by mineralization in simulated body fluid (SBF) using the multilayer fabrics as a template. The structure and related properties of the composite scaffolds were characterized using different techniques. PLA/TSF (mass ratio, 9:1) nanofiber yarns with uniform diameters of 72±9µm were obtained by conjugated electrospinning; the presence of 10wt% TSF accelerated the nucleation and growth of hydroxyapatite on the surface of the composite scaffolds in SBF. Furthermore, the compressive mechanical properties of the PLA/TSF multilayer nanofiber fabrics were improved after mineralization; the compressive modulus and stress of the mineralized composite scaffolds were 32.8 and 3.0 times higher than that of the composite scaffolds without mineralization, respectively. Interestingly, these values were higher than those of scaffolds containing random nanofibers. Biological assay results showed that the mineralization and multilayer fabric structure of the composite nanofiber scaffolds significantly increased cell adhesion and proliferation and enhanced the mesenchymal stem cell differentiation toward osteoblasts. Our results indicated that the mineralized nanofiber scaffolds with multilayer fabrics possessed excellent cytocompatibility and good osteogenic activity, making them versatile biocompatible scaffolds for bone tissue engineering.


Assuntos
Fibroínas/química , Ácido Láctico/química , Nanofibras/química , Ácido Poliglicólico/química , Engenharia Tecidual , Fosfatase Alcalina/metabolismo , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Colágeno Tipo I/metabolismo , Força Compressiva , Durapatita/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Microscopia Confocal , Osteocalcina/metabolismo , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Espectroscopia de Infravermelho com Transformada de Fourier , Tecidos Suporte/química
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