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1.
Phys Med Biol ; 69(9)2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38530300

RESUMO

Objective.The successful implementation of FLASH radiotherapy in clinical settings, with typical dose rates >40 Gy s-1, requires accurate real-time dosimetry.Approach.Silicon carbide (SiC) p-n diode dosimeters designed for the stringent requirements of FLASH radiotherapy have been fabricated and characterized in an ultra-high pulse dose rate electron beam. The circular SiC PiN diodes were fabricated at IMB-CNM (CSIC) in 3µm epitaxial 4H-SiC. Their characterization was performed in PTB's ultra-high pulse dose rate reference electron beam. The SiC diode was operated without external bias voltage. The linearity of the diode response was investigated up to doses per pulse (DPP) of 11 Gy and pulse durations ranging from 3 to 0.5µs. Percentage depth dose measurements were performed in ultra-high dose per pulse conditions. The effect of the total accumulated dose of 20 MeV electrons in the SiC diode sensitivity was evaluated. The temperature dependence of the response of the SiC diode was measured in the range 19 °C-38 °C. The temporal response of the diode was compared to the time-resolved beam current during each electron beam pulse. A diamond prototype detector (flashDiamond) and Alanine measurements were used for reference dosimetry.Main results.The SiC diode response was independent both of DPP and of pulse dose rate up to at least 11 Gy per pulse and 4 MGy s-1, respectively, with tolerable deviation for relative dosimetry (<3%). When measuring the percentage depth dose under ultra-high dose rate conditions, the SiC diode performed comparably well to the reference flashDiamond. The sensitivity reduction after 100 kGy accumulated dose was <2%. The SiC diode was able to follow the temporal structure of the 20 MeV electron beam even for irregular pulse estructures. The measured temperature coefficient was (-0.079 ± 0.005)%/°C.Significance.The results of this study demonstrate for the first time the suitability of silicon carbide diodes for relative dosimetry in ultra-high dose rate pulsed electron beams up to a DPP of 11 Gy per pulse.


Assuntos
Compostos Inorgânicos de Carbono , Dosímetros de Radiação , Radiometria , Radiometria/métodos , Compostos de Silício , Elétrons
2.
PLoS One ; 19(3): e0295938, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38466758

RESUMO

In order to solve the problem that the skid resistance of concrete pavement in tunnel deteriorates rapidly, which is easy to cause traffic accidents, the anti-skid rapid elevation technology of surface treatment is proposed. Wear tests were used to investigate the effects of concrete surface roughness, properties of modified emulsified asphalt binder and anti-skid fine aggregate type on long-term skid resistance of treated surfaces. The results show that the four coarsening methods of fine milling, milling, grooving and brooming can improve the skid resistance of concrete, and the skid resistance durability of fine milling and milling is better. The adhesive property of modified emulsified asphalt is the best when the content of water-based epoxy resin is 20%. In different aggregates, the anti-skid effect is better when silicon carbide is used as anti-skid aggregate and the particle size is 0.6mm:0.3mm = 2:3. The method of fine milling of concrete surface + spraying epoxy emulsified asphalt + spreading silicon carbide can effectively improve the anti-skid performance of the original concrete pavement, and the feasibility of the scheme is verified by the test road. The research results have a good reference value for improving the skid resistance of tunnel concrete pavement.


Assuntos
Acidentes de Trânsito , Compostos Inorgânicos de Carbono , Hidrocarbonetos , Compostos de Silício , Tamanho da Partícula
3.
ACS Appl Bio Mater ; 7(2): 892-908, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38253516

RESUMO

In this study, we have synthesized a bioactive glass with composition 45SiO2-20Na2O-23CaO-6P2O5-2.5B2O3-1ZnO-2MgO-0.5CaF2 (wt %). Further, it has been incorporated with 0.4 wt % iron carbide nanoparticles to prepare magnetic bioactive glass (MBG) with good heat generation capability for potential applications in magnetic field-assisted hyperthermia. The MBG scaffolds have been fabricated using extrusion-based additive manufacturing by mixing MBG powder with 25% Pluronic F-127 solution as the binder. The saturation magnetization of iron carbide nanoparticles in the bioactive glass matrix has been found to be 80 emu/g. The morphological analysis (pore size distribution, porosity, open pore network modeling, tortuosity, and pore interconnectivity) was done using an in-house developed methodology that revealed the suitability of the scaffolds for bone tissue engineering. The compressive strength (14.3 ± 1.6 MPa) of the MBG scaffold was within the range of trabecular bone. The in vitro test using simulated body fluid (SBF) showed the formation of apatite indicating the bioactive nature of scaffolds. Further, the drug delivery behaviors of uncoated and polycaprolactone (PCL) coated MBG scaffolds have been evaluated by loading an anticancer drug (Mitomycin C) onto the scaffolds. While the uncoated scaffold demonstrated the drug's burst release for the initial 80 h, the PCL-coated scaffold showed the gradual release of the drug. These results demonstrate the potential of the proposed MBG for bone tissue engineering and drug delivery applications.


Assuntos
Compostos Inorgânicos de Carbono , Compostos de Ferro , Engenharia Tecidual , Tecidos Suporte , Engenharia Tecidual/métodos , Vidro , Osso e Ossos
4.
Adv Mater ; 36(9): e2307006, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37924225

RESUMO

The ferroptosis pathway is recognized as an essential strategy for tumor treatment. However, killing tumor cells in deep tumor regions with ferroptosis agents is still challenging because of distinct size requirements for intratumoral accumulation and deep tumor penetration. Herein, intelligent nanocapsules with size-switchable capability that responds to acid/hyperthermia stimulation to achieve deep tumor ferroptosis are developed. These nanocapsules are constructed using poly(lactic-co-glycolic) acid and Pluronic F127 as carrier materials, with Au-Fe2 C Janus nanoparticles serving as photothermal and ferroptosis agents, and sorafenib (SRF) as the ferroptosis enhancer. The PFP@Au-Fe2 C-SRF nanocapsules, designed with an appropriate size, exhibit superior intratumoral accumulation compared to free Au-Fe2 C nanoparticles, as evidenced by photoacoustic and magnetic resonance imaging. These nanocapsules can degrade within the acidic tumor microenvironment when subjected to laser irradiation, releasing free Au-Fe2 C nanoparticles. This enables them to penetrate deep into tumor regions and disrupt intracellular redox balance. Under the guidance of imaging, these PFP@Au-Fe2 C-SRF nanocapsules effectively inhibit tumor growth when exposed to laser irradiation, capitalizing on the synergistic photothermal and ferroptosis effects. This study presents an intelligent formulation based on iron carbide for achieving deep tumor ferroptosis through size-switchable cascade delivery, thereby advancing the comprehension of ferroptosis in the context of tumor theranostics.


Assuntos
Compostos Inorgânicos de Carbono , Ferroptose , Hipertermia Induzida , Compostos de Ferro , Nanocápsulas , Nanopartículas , Neoplasias , Humanos , Linhagem Celular Tumoral , Neoplasias/terapia , Sorafenibe , Hipertermia/terapia , Hipertermia Induzida/métodos , Microambiente Tumoral
5.
Adv Sci (Weinh) ; 11(8): e2305459, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37988692

RESUMO

Magnetic nanomaterials have played a crucial role in promoting the application of nanotechnology in the biomedical field. Although conventional magnetic nanomaterials such as iron oxide nanoparticles (NPs) are used as biosensors, drug delivery vehicles, diagnostic and treatment agents for several diseases, the persistent pursuit of high-performance technologies has prompted researchers to continuously develop new types of magnetic nanomaterials such as iron carbide NPs. Considering their potential application in biomedicine, magnetic NPs responsive to exogenous or endogenous stimuli are developed, thereby enhancing their applicability in more complex versatile scenarios. In this review, the synthesis and surface modification of magnetic NPs are focused, particularly iron carbide NPs. Subsequently, exogenous and endogenous stimuli-responsive magnetic NP-based theranostic platforms are introduced, particularly focusing on nanozyme-based technologies and magnetic NP-mediated immunotherapy, which are emerging stimuli-responsive treatments. Finally, the challenges and perspectives of magnetic NPs to accelerate future research in this field are discussed.


Assuntos
Compostos Inorgânicos de Carbono , Compostos de Ferro , Nanopartículas de Magnetita , Medicina de Precisão , Nanopartículas de Magnetita/uso terapêutico , Sistemas de Liberação de Medicamentos , Magnetismo
6.
Environ Sci Pollut Res Int ; 30(18): 51861-51874, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36820976

RESUMO

Against achieving carbon peaking by 2030 and carbon neutrality by 2060 context in China, the new energy demonstration city policy (NEDCP) has a crucial function to perform in promoting resource utilization efficiency, building the green development policy system, and facilitating carbon emission reduction. However, existing research has rarely investigated the contribution of NEDCP on carbon reduction. To investigate the policy effect of NEDCP, the differences-in-differences (DID) model is introduced to quantify the influence of NEDCP on carbon reduction, taking a statistical sample of 285 Chinese cities over the period 2005-2017 on the basis of exploring the intrinsic mechanism of NEDCP on carbon emissions. The statistical results reveal that NEDCP significantly inhibits carbon emissions. NEDCP's dampening impact on carbon reduction is more pronounced in the eastern area but not in other areas. City size and resource endowment heterogeneity results suggest that NEDCP significantly inhibits the output of carbon emissions in non-resource-based and large cities but insignificantly in resource-based and small- and medium-sized cities. Finally, we conclude that policy-makers should not only broaden the scope of NEDCP implementation continuously but also design relevant policy combination tools following the basic characteristics of each city to provide institutional guarantees for achieving carbon emission reduction.


Assuntos
Compostos Inorgânicos de Carbono , Planejamento de Cidades , Conservação dos Recursos Naturais , Monitoramento Ambiental , Política Pública , Carbono , Compostos Inorgânicos de Carbono/efeitos adversos , Compostos Inorgânicos de Carbono/análise , Dióxido de Carbono , China , Cidades , Desenvolvimento Econômico , Política Ambiental , Monitoramento Ambiental/métodos
7.
Environ Sci Pollut Res Int ; 30(18): 52141-52156, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36823461

RESUMO

The "double-carbon" policy is a new opportunity for the transformation of China's production sector. With steady economic growth, each province has proposed specific policies aimed at cleaner production. However, the interactions between regions and the complex linkages between industries have hindered the implementation of the "double-carbon" policy. In order to address this issue, we introduced a complex network framework with multiple industries at a national level. The framework aimed to clarify whether there is fluctuation diffusion in China's multi-province multi-industry carbon emission system, to identify key industries and regions, and to answer the question of "who" is the most effective in governance. The results showed that the fluctuations of industrial carbon emissions had a cross-regional diffusion effect in China indeed. The diffusion capacity of industry fluctuation depends on whether the industry is located at a "hub" position in the network. Hub industries with strong capacity can spread the carbon emission fluctuation of themselves and upstream or downstream industries to the whole country through regional interactions. This characteristic of the hub industry should be taken into account in governance to maximize the effectiveness of emission reduction. Shandong and Inner Mongolia, as important provinces for the production of intermediate products and energy chemicals in China, had a greater role to play in global carbon supply push from their hub industries than in the demand pull. The pulling capacity of Beijing-Tianjin-Hebei region to the national carbon demand side was greater than that of Yangtze River Delta and Pearl River Delta. These findings might have implications for environmental and economic policymaking, particularly with regard to cross-provincial coordinated systemic solutions and policy anchors for synergy with industries.


Assuntos
Compostos Inorgânicos de Carbono , Carbono , Desenvolvimento Econômico , Monitoramento Ambiental , Política Ambiental , Indústrias , Humanos , Pequim , Carbono/análise , Compostos Inorgânicos de Carbono/análise , Dióxido de Carbono/análise , China , Indústrias/organização & administração , Indústrias/normas , Monitoramento Ambiental/métodos , Monitoramento Ambiental/normas
8.
PLoS One ; 18(1): e0277331, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36638108

RESUMO

Most silicon carbide (SiC) MOSFET models are application-specific. These are already defined by the manufacturers and their parameters are mostly partially accessible due to restrictions. The desired characteristic of any SiC model becomes highly important if an individual wants to visualize the impact of changing intrinsic parameters as well. Also, it requires a model prior knowledge to vary these parameters accordingly. This paper proposes the parameter extraction and its selection for Silicon Carbide (SiC) power N-MOSFET model in a unique way. The extracted parameters are verified through practical implementation with a small-scale high power DC-DC 5 to 2.5 output voltage buck converter using both hardware and software emphasis. The parameters extracted using the proposed method are also tested to verify the static and dynamic characteristics of SiC MOSFET. These parameters include intrinsic, junction and overlapping capacitance. The parameters thus extracted for the SiC MOSFET are analyzed by device performance. This includes input, output transfer characteristics and transient delays under different temperature conditions and loading capabilities. The simulation and experimental results show that the parameters are highly accurate. With its development, researchers will be able to simulate and test any change in intrinsic parameters along with circuit emphasis.


Assuntos
Fontes de Energia Elétrica , Software , Simulação por Computador , Compostos Inorgânicos de Carbono
9.
Molecules ; 27(18)2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36144499

RESUMO

Protein corona composition and precise physiological understanding of differentially expressed proteins are key for identifying disease biomarkers. In this report, we presented a distinctive quantitative proteomics table of molecular cell signaling differentially expressed proteins of corona that formed on iron carbide nanoparticles (NPs). High-performance liquid chromatography/electrospray ionization coupled with ion trap mass analyzer (HPLC/ESI-Orbitrap) and MASCOT helped quantify 142 differentially expressed proteins. Among these proteins, 104 proteins showed upregulated behavior and 38 proteins were downregulated with respect to the control, whereas 48, 32 and 24 proteins were upregulated and 8, 9 and 21 were downregulated CW (control with unmodified NPs), CY (control with modified NPs) and WY (modified and unmodified NPs), respectively. These proteins were further categorized on behalf of their regularity, locality, molecular functionality and molecular masses using gene ontology (GO). A STRING analysis was used to target the specific range of proteins involved in metabolic pathways and molecular processing in different kinds of binding functionalities, such as RNA, DNA, ATP, ADP, GTP, GDP and calcium ion bindings. Thus, this study will help develop efficient protocols for the identification of latent biomarkers in early disease detection using protein fingerprints.


Assuntos
Nanopartículas , Coroa de Proteína , Difosfato de Adenosina , Trifosfato de Adenosina , Cálcio , Compostos Inorgânicos de Carbono , Análise por Conglomerados , Guanosina Trifosfato , Compostos de Ferro , Nanopartículas/química , Coroa de Proteína/química , Proteínas/metabolismo , Proteômica/métodos , RNA
10.
Proc Natl Acad Sci U S A ; 119(33): e2203287119, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35939711

RESUMO

Electrical neuron stimulation holds promise for treating chronic neurological disorders, including spinal cord injury, epilepsy, and Parkinson's disease. The implementation of ultrathin, flexible electrodes that can offer noninvasive attachment to soft neural tissues is a breakthrough for timely, continuous, programable, and spatial stimulations. With strict flexibility requirements in neural implanted stimulations, the use of conventional thick and bulky packages is no longer applicable, posing major technical issues such as short device lifetime and long-term stability. We introduce herein a concept of long-lived flexible neural electrodes using silicon carbide (SiC) nanomembranes as a faradic interface and thermal oxide thin films as an electrical barrier layer. The SiC nanomembranes were developed using a chemical vapor deposition (CVD) process at the wafer level, and thermal oxide was grown using a high-quality wet oxidation technique. The proposed material developments are highly scalable and compatible with MEMS technologies, facilitating the mass production of long-lived implanted bioelectrodes. Our experimental results showed excellent stability of the SiC/silicon dioxide (SiO2) bioelectronic system that can potentially last for several decades with well-maintained electronic properties in biofluid environments. We demonstrated the capability of the proposed material system for peripheral nerve stimulation in an animal model, showing muscle contraction responses comparable to those of a standard non-implanted nerve stimulation device. The design concept, scalable fabrication approach, and multimodal functionalities of SiC/SiO2 flexible electronics offer an exciting possibility for fundamental neuroscience studies, as well as for neural stimulation-based therapies.


Assuntos
Terapia por Estimulação Elétrica , Neuroestimuladores Implantáveis , Nanoestruturas , Semicondutores , Compostos Inorgânicos de Carbono/química , Terapia por Estimulação Elétrica/instrumentação , Membranas Artificiais , Compostos de Silício/química , Dióxido de Silício/química
11.
J Colloid Interface Sci ; 627: 956-968, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35901574

RESUMO

Carbon dots (C-dots) developed from beetroot is used for the rational design of cadmium sulphide based heterojunction photocatalysts (C-dots@CdS) using hydrothermal technique. The crystal structure, phase, morphology and optical characteristics of the synthesised materials are determined using X-ray diffraction (XRD), High resolution transmission electron microscopy (HR-TEM), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Visible diffuse reflectance spectroscopy (UV-DRS), photoluminescence spectroscopy (PL spectroscopy), BET adsorption, X-ray photoelectron spectroscopy (XPS) and electrochemical studies. Using C-dots@CdS catalytic system, a superior photocatalytic activity relative to the undecorated CdS is observed. Among the C-dots@CdS samples, the CdS loaded with 6 wt% of C-dots exhibited enhanced hydrogen evolution rate compared with other samples considered for the study. CdS nanospheres modified with C-dots (6 wt%) resulted in the photocatalytic hydrogen evolution rate of 1582 µmolg-1 against 849 µmolg-1 evolution rate obtained for CdS nanospheres within 3 h. In spite of being 0D/0D type nano-heteroarchitecture, C-dots@CdS system obtained an apparent quantum yield of 6.37 % for the catalytic dosage of 20 mg under the irradiation of visible light. CdS in the C-dots@CdS system serves as the light harvester while C-dots with discernible edges can maintain the continuous supply of photo-excited charge carriers and hence can reduce the charge-carrier recombination. Further, the photodegradation of crystal violet dye using the optimised dosage of C-dots@CdS-6 exhibited an efficiency of 97.3 % in 120 min of visible light irradiation under neutral conditions. The detailed kinetic study reveals that the mechanism of photodegradation of crystal violet dye using C-dots@CdS system can be described using pseudo-second-order kinetics. The presence of oxygen rich hydrophilic surface functionalities of C-dots, the formation of near-surface heterojunction and the suitable band structure of C-dots@CdS system leading to the optimum charge carrier separation kinetics can be attributed to the enhanced photocatalytic performance. This work offers a promising strategy to develop bio-derived C-dots based heterojunction photocatalyst to address the burgeoning energy and environmental demands.


Assuntos
Carbono , Nanosferas , Cádmio , Compostos de Cádmio , Compostos Inorgânicos de Carbono , Violeta Genciana , Hidrogênio , Luz , Oxigênio , Sulfetos
12.
ACS Nano ; 16(7): 10890-10903, 2022 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-35816450

RESUMO

The integration of micro- and nanoelectronics into or onto biomedical devices can facilitate advanced diagnostics and treatments of digestive disorders, cardiovascular diseases, and cancers. Recent developments in gastrointestinal endoscopy and balloon catheter technologies introduce promising paths for minimally invasive surgeries to treat these diseases. However, current therapeutic endoscopy systems fail to meet requirements in multifunctionality, biocompatibility, and safety, particularly when integrated with bioelectronic devices. Here, we report materials, device designs, and assembly schemes for transparent and stable cubic silicon carbide (3C-SiC)-based bioelectronic systems that facilitate tissue ablation, with the capability for integration onto the tips of endoscopes. The excellent optical transparency of SiC-on-glass (SoG) allows for direct observation of areas of interest, with superior electronic functionalities that enable multiple biological sensing and stimulation capabilities to assist in electrical-based ablation procedures. Experimental studies on phantom, vegetable, and animal tissues demonstrated relatively short treatment times and low electric field required for effective lesion removal using our SoG bioelectronic system. In vivo experiments on an animal model were conducted to explore the versatility of SoG electrodes for peripheral nerve stimulation, showing an exciting possibility for the therapy of neural disorders through electrical excitation. The multifunctional features of SoG integrated devices indicate their high potential for minimally invasive, cost-effective, and outcome-enhanced surgical tools, across a wide range of biomedical applications.


Assuntos
Compostos Inorgânicos de Carbono , Compostos de Silício , Animais , Eletrônica , Eletrodos
13.
J Microencapsul ; 39(4): 341-351, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35670223

RESUMO

AIM: In this investigation, Zinc-silicon carbide (Zn-SiC) materials were fabricated by a simple approach by using Zn nanoparticles (Zn-NPs) loaded on silicon carbide (SiC) with enhanced antibacterial and healing activity. METHODS: Zn-NPs loaded on SiC fabricated by the DIY laser melting technique. The TEM and Zeta-sizer confirmed the morphology and size of the nanoparticles. The characterisation was done using Fourier transforms infra-red spectroscopy, and X-ray diffraction, thermogravimetric analysis. Further, the fabricated nanoparticles were evaluated for their mechanical properties and biocompatibility under storage conditions. In vivo wound healing was measured by observing a percentage reduction in the wound. RESULTS: Zn-SiC NPs have 54.6 ± 5.25 nm mean particle size, -15.9 ± 2.35 mV zeta potential with 0.187 ± 0.05 polydispersity index. The nanoparticles showed good biocompatibility and in vivo wound healing properties. CONCLUSIONS: These results strongly support the possibility of using these Zn particles loaded on SiC NPs as a promising wound healing agent after caesarean section.


Assuntos
Nanocompostos , Zinco , Bandagens , Compostos Inorgânicos de Carbono , Sobrevivência Celular , Cesárea , Feminino , Humanos , Gravidez , Compostos de Silício , Zinco/química
14.
Magn Reson Imaging ; 90: 37-43, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35413425

RESUMO

PURPOSE: The use of dielectric pads to redistribute the radiofrequency fields is currently a popular solution for 7 T MRI practical applications, especially in brain imaging. In this work, we tackle several downsides of the previous generation of dielectric pads. This new silicon carbide recipe makes them MR invisible and greatly extends the performance lifespan. METHOD: We produce a set of two 10x10x1cm3 dielectric pads based on silicon carbide (SiC) powder dispersed in 4-Fluoro 1, 3-dioxalan-2-one (FEC) and polyethylene Glycol (PEG). The stability of the complex permittivity and the invisibility of the pads are characterized experimentally. Numerical simulations are done to evaluate global and local SAR over the head in presence of the pads. B0, B1+ and standard imaging sequences are performed on healthy volunteers. RESULTS: SiC pads are compared to state-of-the-art perovskite based dielectric pads with similar dielectric properties (barium titanate). Numerical simulations confirm that head and local SAR are similar. MRI measurements confirm that the pads do not induce susceptibility artefacts and improve B1+ amplitude in the temporal lobe regions by 25% on average. CONCLUSION: We demonstrate the long-term performance and invisibility of these new pads in order to increase the contrast in the brain temporal lobes in a commercial 7 T MRI head coil.


Assuntos
Artefatos , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Compostos Inorgânicos de Carbono , Humanos , Imageamento por Ressonância Magnética/métodos , Imagens de Fantasmas , Ondas de Rádio , Compostos de Silício
15.
Waste Manag ; 144: 263-271, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35421706

RESUMO

The paper presents the results of the experimental studies addressing the production of silicon carbide from glass waste by electric arc plasma processing. A feature of the method is the possibility of its implementation without the use of vacuum equipment. It is possible due to the effect of self-shielding of the reaction volume from atmospheric oxygen. This approach significantly simplifies the design of the electric arc reactor and its performance. After plasma processing of various types of glass waste (such as bottle glass, window glass, medical glass, quartz glass, parts of worn-out scientific and industrial equipment), silicon carbide based material was produced. Silicon carbide was obtained from a mixture of various glass waste at a current 200 A, where blend was first purified from unbound carbon and then was consolidated by spark plasma sintering at 1800 °C and 60 MPa pressure for 10 min. As a result, a ceramic bulk sample was fabricated from a mixture of glass waste of various origin. Such sample was characterized with hardness of 14.8 GPa, and attained density of 92.5 %. Despite a possible increase in the density due to impurities and inhomogeneities, the hardness of the fabricated sample is comparable to that of other silicon carbide based materials, including commercial ones. Since the hardness of the produced silicon carbide based material is comparable to that of commercial materials, the use of glass waste of various origin could be feasible for synthesis of silicon carbide based powders.


Assuntos
Compostos Inorgânicos de Carbono , Compostos de Silício , Cerâmica , Vidro
16.
Small ; 18(19): e2201039, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35419970

RESUMO

Silicon carbide (SiC) aerogels are promising thermal insulators that are lightweight and possess high thermal stability. However, their application is hindered by their brittleness. Herein, an air suction effect induction (ASEI) strategy is proposed to fabricate a super thermally insulating SiC aerogel (STISA). The ASEI strategy exploits the air suction effect to subtly regulate the directional flow of the SiO gas, which can induce directional growth and assembly of SiC nanowires to form a directional lamellar structure. The sintering time is significantly reduced by >90%. Significant improvements in the compression and elasticity performance of the STISA are achieved upon the formation of a directional lamellar structure through the ASEI strategy. Moreover, the lamellar structure endows the STISA with an ultralow thermal conductivity of 0.019 W m-1 K-1 . The ASEI strategy paves the way for structural design of advanced ceramic aerogels for super thermal insulation.


Assuntos
Ar , Compostos Inorgânicos de Carbono , Elasticidade , Compostos de Silício , Sucção , Condutividade Térmica
17.
Water Res ; 216: 118267, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35306459

RESUMO

Ceramic membranes have drawn increasing attention in oily wastewater treatment as an alternative to their traditional polymeric counterparts, yet persistent membrane fouling is still one of the largest challenges. Particularly, little is known about ceramic membrane fouling by oil-in-water (O/W) emulsions in constant flux filtration modes. In this study, the effects of emulsion chemistry (surfactant concentration, pH, salinity and Ca2+) and operation parameters (permeate flux and filtration time) were comparatively evaluated for alumina and silicon carbide (SiC) deposited ceramic membranes, with different physicochemical surface properties. The original membranes were made of 100% alumina, while the same membranes were also deposited with a SiC layer to change the surface charge and hydrophilicity. The SiC-deposited membrane showed a lower reversible and irreversible fouling when permeate flux was below 110 L m-2 h-1. In addition, it exhibited a higher permeance recovery after physical and chemical cleaning, as compared to the alumina membranes. Increasing sodium dodecyl sulfate (SDS) concentration in the feed decreased the fouling of both membranes, but to a higher extent in the alumina membranes. The fouling of both membranes could be reduced with increasing the pH of the emulsion due to the enhanced electrostatic repulsion between oil droplets and membrane surface. Because of the screening of surface charge in a high salinity solution (100 mM NaCl), only a small difference in irreversible fouling was observed for alumina and SiC-deposited membranes under these conditions. The presence of Ca2+ in the emulsion led to high irreversible fouling of both membranes, because of the compression of diffusion double layer and the interactions between Ca2+ and SDS. The low fouling tendency and/or high cleaning efficiency of the SiC-deposited membranes indicated their potential for oily wastewater treatment.


Assuntos
Membranas Artificiais , Purificação da Água , Óxido de Alumínio , Compostos Inorgânicos de Carbono , Emulsões , Filtração , Óleos/química , Compostos de Silício , Água
18.
Environ Pollut ; 300: 118965, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35134429

RESUMO

Zero valent iron-loaded biochar (Fe0-BC) has shown promise for the removal of various organic pollutants, but is restricted by reduced specific surface area, low utilization efficiency and limited production of reactive oxygen species (ROS). In this study, iron carbide-loaded activated biochar (Fe3C-AB) with a high surface area was synthesized through the pyrolysis of H3PO4 activated biochar with Fe(NO3)3, tested for removing bisphenol A (BPA) and elucidated the adsorption and degradation mechanisms. As a result, H3PO4 activated biochar was beneficial for the transformation of Fe0 to Fe3C. Fe3C-AB exhibited a significantly higher removal rate and removal capacity for BPA than that of Fe0-BC within a wide pH range of 5.0-11.0, and its performance was maintained even under extremely high salinity and different water sources. Moreover, X-ray photoelectron spectra and density functional theory calculations confirmed that hydrogen bonds were formed between the COOH groups and BPA. 1O2 was the major reactive species, constituting 37.0% of the removal efficiency in the degradation of BPA by Fe3C-AB. Density functional reactivity theory showed that degradation pathway 2 of BPA was preferentially attacked by ROS. Thus, Fe3C-AB with low cost and excellent recycling performance could be an alternative candidate for the efficient removal of contaminants.


Assuntos
Ferro , Poluentes Químicos da Água , Adsorção , Compostos Benzidrílicos , Compostos Inorgânicos de Carbono , Carvão Vegetal/química , Ferro/química , Compostos de Ferro , Fenóis , Poluentes Químicos da Água/análise
19.
Nat Commun ; 13(1): 6, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013167

RESUMO

Myocardial infarction causes 7.3 million deaths worldwide, mostly for fibrillation that electrically originates from the damaged areas of the left ventricle. Conventional cardiac bypass graft and percutaneous coronary interventions allow reperfusion of the downstream tissue but do not counteract the bioelectrical alteration originated from the infarct area. Genetic, cellular, and tissue engineering therapies are promising avenues but require days/months for permitting proper functional tissue regeneration. Here we engineered biocompatible silicon carbide semiconductive nanowires that synthetically couple, via membrane nanobridge formations, isolated beating cardiomyocytes over distance, restoring physiological cell-cell conductance, thereby permitting the synchronization of bioelectrical activity in otherwise uncoupled cells. Local in-situ multiple injections of nanowires in the left ventricular infarcted regions allow rapid reinstatement of impulse propagation across damaged areas and recover electrogram parameters and conduction velocity. Here we propose this nanomedical intervention as a strategy for reducing ventricular arrhythmia after acute myocardial infarction.


Assuntos
Infarto do Miocárdio , Miócitos Cardíacos/fisiologia , Nanofios , Arritmias Cardíacas/terapia , Compostos Inorgânicos de Carbono , Ventrículos do Coração , Humanos , Infarto do Miocárdio/fisiopatologia , Infarto do Miocárdio/terapia , Compostos de Silício
20.
Nat Mater ; 21(1): 8-9, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34795401
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