Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Mais filtros

Base de dados
Intervalo de ano de publicação
Anal Chem ; 94(2): 600-605, 2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-34920663


The present detection method for hepatitis B virus (HBV) drug-resistant mutation has a high misdiagnosis rate and usually needs to meet stringent requirements for technology and equipment, leading to complex and time-consuming manipulation and drawback of high costs. Herein, with the purpose of developing cost-effective, highly efficient, and handy diagnosis for HBV drug-resistant mutants, we propose an electrochemical signal-on strategy through the three-way junction (3WJ) transduction and exonuclease III (Exo III)-assisted catalyzed hairpin assembly (CHA). To achieve single-copy gene detection, loop-mediated nucleic acid isothermal amplification (LAMP), one of the highly promising and compatible techniques to revolutionize point-of-care genetic detection, is first adopted for amplification. The rtN236T mutation, an error encoded by codon 236 of the reverse transcriptase region of HBV DNA, was employed as the model gene target. Under the optimized conditions, it allows end-point transduction from HBV drug-resistant mutants-genomic information to electrochemical signals with ultrahigh sensitivity, specificity, and signal-to-noise ratio, showing the lowest detection concentration down to 2 copies/µL. Such a method provides a possibly new principle for ideal in vitro diagnosis, supporting the construction of a clinic HBV diagnosis platform with high accuracy and generalization. Moreover, it is not restricted by specific nucleic acid sequences but can be applied to the detection of various disease genes, laying the foundation for multiple detection.

Técnicas Biossensoriais , Vírus da Hepatite B , Técnicas Biossensoriais/métodos , Catálise , DNA/genética , Exodesoxirribonucleases , Vírus da Hepatite B/genética , Técnicas de Amplificação de Ácido Nucleico/métodos
Anal Chem ; 93(35): 11956-11964, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34424659


Coronavirus diseases such as the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), pose serious threats. Portable and accurate nucleic acid detection is still an urgent need to achieve on-site virus screening and timely infection control. Herein, we have developed an on-site, semiautomatic detection system, aiming at simultaneously overcoming the shortcomings suffered by various commercially available assays, such as low accuracy, poor portability, instrument dependency, and labor intensity. Ultrasensitive isothermal amplification [i.e., reverse transcription loop-mediated isothermal amplification (RT-LAMP)] was applied to generate intensified SARS-CoV-2 RNA signals, which were then transduced to portable commercial pregnancy test strips (PTSs) via ultraspecific human chorionic gonadotropin (hCG)-conjugated toehold-mediated strand exchange (TMSE) probes (hCG-P). The entire detection was integrated into a four-channel, palm-size microfluidic device, named the microfluidic point-of-care (POC) diagnosis system based on the PTS (MPSP) detection system. It provides rapid, cost-effective, and sensitive detection, of which the lowest concentration of detection was 0.5 copy/µL of SARS-CoV-2 RNA, regardless of the presence of other similar viruses, even highly similar severe acute respiratory syndrome coronavirus (SARS-CoV). The successful detection of the authentic samples from different resources evaluated the practical application. The commercial PTS provides a colorimetric visible signal, which is instrument- and optimization-free. Therefore, this MPSP system can be immediately used for SARS-CoV-2 emergency detection, and it is worthy of further optimization to achieve full automation and detection for other infectious diseases.

COVID-19 , Testes de Gravidez , Feminino , Humanos , Dispositivos Lab-On-A-Chip , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Sistemas Automatizados de Assistência Junto ao Leito , Gravidez , RNA Viral/genética , SARS-CoV-2 , Sensibilidade e Especificidade
Sci Total Environ ; 793: 148597, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34182453


Decades of researches have proved that pyrolysis can not only realize the harmless disposal of waste tire, but also carry out the goal of waste resource utilization via recycling pyrolytic products (e.g. pyrolytic carbon black, CBp). The current work studied the effect of CBp obtained from the commercial scale pyrolysis of waste tire, on the properties of natural rubber and butadiene rubber. CBp was incorporated into a carbon black quality identification standard formula in combination with N234 commercial carbon black (cCB) first. After screening a better substitution ratio, the composite material of CBp and cCB was mixed with more additives, and the experiment was carried out with a real production formula. To restore the practical production situation, the experiment process adopts the most commonly used process to avoid major changes in commercial production. CBp was tested at increasing loading levels as partial or full replacement of cCB. The physico-mechanical properties of the rubber compounds were studied by tests of physical, mechanical, and vulcanization properties. With the increase in the amount of CBp added, the physical and mechanical properties of the rubber compound showed a trend of slightly increasing first and then rapidly decreasing. The addition of CBp can increase the yield strength and stiffness of the rubber, but it may also lead to a decrease in hardness. Meanwhile, the substitution ratio of CBp up to 50% has been proven to improve safety and achieve a more stable vulcanization process of rubber compounds. CBp can replace up to half of cCB without significantly reducing the quality of tire rubber. The economic value of partial replacement of cCB by CBp has also been evaluated, demonstrating that adding a small amount of CBp can directly reduce the cost of raw materials, indirectly reduce the use of fossil energy promoting carbon dioxide reduction worldwide.

Pirólise , Fuligem , Reciclagem , Borracha
Waste Manag Res ; 39(12): 1440-1450, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33860697


Pyrolysis offers a more focused alternative to waste tyres treatment. Pyrolytic carbon black (CBp), the main product of waste tyre pyrolysis, and its modified species can be applied to tyre manufacturing realizing its high-value utilization. Modified pyrolytic carbon black/natural rubber composites prepared by a wet compounding (WC) and latex mixing process have become an innovative technology route for waste tyre remanufacturing. The main properties and applications of CBp reported in recent years are reviewed, and the main difficulties affecting its participation in tyre recycling are pointed out. The research progress of using WC technology to replace dry mixing manufacturing of new tyres is summarized. Through literature data and comparative studies, this paper points out that the characteristic of high ash content can be well utilized if CBp is applied to tyre manufacturing. This mini-review proposes a new method for high-value utilization of CBp. The composite mixing of CBp and carbon nano-materials under wet conditions is conducive to the realization of their good dispersion in the rubber matrix. This provides a new idea for customer resource integration and connection of industry development between the tyre production industry and waste tyre disposal management.

Carbono , Pirólise , Reciclagem , Borracha
Sci Total Environ ; 772: 145507, 2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-33770869


Environmental problems caused by waste tires have become so glaring that it has attracted wide attention. This case study seeks to examine the properties of carbon black from waste tires continuous commercial scale pyrolysis. This work aims to contribute to this growing area of research by exploring the difference between the properties of products under the condition of mass production and those under the condition of laboratory scale or pilot scale production. A pyrolysis prototype, with a waste tire mass flow rate of 50-60 t d-1 was constructed and introduced. Steel-included tire granulates were pyrolyzed in micro-negative pressure furnace at about 420 ± 20 °C. This kind of nonstripping, micro-negative pressure and low-temperature continuous thermal pyrolysis technology can reduce the stripping process between rubber and steel wire, reduce the requirement of equipment sealing, and improve the utilization rate of resources. All three products including pyrolytic carbon black (CBp), tire pyrolysis oil (TPO) and pyrolysis gas showed good characteristics. Pyrolysis gas had been successfully re-used for pyrolysis furnaces and dryers. The higher heating value of TPO estimated to 37-40 MJ/ kg, which was comparable to diesel fuel through further treatment. Results of proximate analysis, element analysis, XPS, FTIR, XRD and surface structure confirmed that CBp with commercial scale production showed no apparent data difference with those in other small scale research cases. The morphological changes of carbon black particles were suggested, revealing a possible internal structure of CBp aggregates in commercial scale pyrolysis. This study is an attempt to push the existing research in this field to commercial production. This work generates fresh insight into the viability of continuous commercial pyrolysis and demonstrates the feasibility of the operation, providing reference for many researchers and units who study the pyrolysis technology of waste tires with the feasibility of industrial production.

Sci Total Environ ; 742: 140235, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32629243


Recently, the recycling of waste tires has caused widespread concern for its environmental issues. The experience of the producer responsibility and tax system is of great beneficial to developing countries. The article also elaborates on the efforts of Chinese government to focus on establishing and perfecting waste tire treatment system by strengthen legislation. The main reasons such as immature market, non-uniform policy and repeated taxation for the survival difficulties of waste tire recycling enterprises in China are summarized. Among numerous resource methods, pyrolysis has been considered as a promising thermochemical process to deal with the waste tires. Unlike other similar reviews that mainly focus on its liquid phase, special attention has been given to solid char, pyrolysis carbon black, due to its wide application and high-value utilization in the future. We summarize the available research on application of pyrolysis carbon black as an alternative to commercial carbon black in rubber manufacture, as activated carbon in pollution control and as biochar for soil improvement. Analysis of the available data revealed that 1) the influence of temperature and time has been basically established; 2) catalyst type, dosage and reactor selection should be adjusted according to product demand; 3) pickling has become the primary means of improving pyrolysis carbon black; 4) the type of modifier and modification method must be adjusted according to the specific characteristics of the raw materials and needs to be combined with the experimental results to realize resource utilization and give full play to its economic value.