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1.
Molecules ; 29(8)2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38675595

RESUMO

The COVID-19 pandemic over recent years has shown a great need for the rapid, low-cost, and on-site detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this study, an aptamer-based colloidal gold nanoparticle lateral flow test strip was well developed to realize the visual detection of wild-type SARS-CoV-2 spike proteins (SPs) and multiple variants. Under the optimal reaction conditions, a low detection limit of SARS-CoV-2 S proteins of 0.68 nM was acquired, and the actual detection recovery was 83.3% to 108.8% for real-world samples. This suggests a potential tool for the prompt detection of SARS-CoV-2 with good sensitivity and accuracy, and a new method for the development of alternative antibody test strips for the detection of other viral targets.


Assuntos
Aptâmeros de Nucleotídeos , COVID-19 , Ouro , Nanopartículas Metálicas , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Humanos , Aptâmeros de Nucleotídeos/química , COVID-19/diagnóstico , COVID-19/virologia , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Fitas Reagentes , SARS-CoV-2/química , Glicoproteína da Espícula de Coronavírus/química
2.
Molecules ; 28(8)2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37110564

RESUMO

Eucommia ulmoides gum (EUG) is a natural polymer predominantly consisting of trans-1,4-polyisoprene. Due to its excellent crystallization efficiency and rubber-plastic duality, EUG finds applications in various fields, including medical equipment, national defense, and civil industry. Here, we devised a portable pyrolysis-membrane inlet mass spectrometry (PY-MIMS) approach to rapidly, accurately, and quantitatively identify rubber content in Eucommia ulmoides (EU). EUG is first introduced into the pyrolyzer and pyrolyzed into tiny molecules, which are then dissolved and diffusively transported via the polydimethylsiloxane (PDMS) membrane before entering the quadrupole mass spectrometer for quantitative analysis. The results indicate that the limit of detection (LOD) for EUG is 1.36 µg/mg, and the recovery rate ranges from 95.04% to 104.96%. Compared to the result of pyrolysis-gas chromatography (PY-GC), the average relative error is 1.153%, and the detection time was reduced to less than 5 min, demonstrating that the procedure was reliable, accurate, and efficient. The method has the potential to be employed to precisely identify the rubber content of natural rubber-producing plants such as Eucommia ulmoides, Taraxacum kok-saghyz (TKS), Guayule, and Thorn lettuce.


Assuntos
Eucommiaceae , Borracha , Eucommiaceae/química , Baías , Pirólise , Cromatografia Gasosa-Espectrometria de Massas
3.
Anal Chem ; 94(7): 3173-3179, 2022 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-35133802

RESUMO

A novel high-throughput aptamer microarray fluorescent method based on thioflavin T (ThT) was established for the sensitive detection of phoxim, parathion, fensulfothion, and isocarbophos. In this work, the aptamers in binding buffer tended to have the antiparallel G-quadruplex structure, which can bind ThT and release its potential fluorescence signal. However, when the organophosphorus pesticides (OPs) were present, partial aptamers preferred to bind them, forcing the displacement of ThT from the G-quadruplex and resulting in the significant decrease in fluorescence signal. Under optimal experimental conditions (12T spacer, 300 nM aptamer, and 80 µM ThT), the OP aptamer microarray has low limits of detection of 25.4 ng/mL for phoxim, 12.0 ng/mL for parathion, 7.7 ng/mL for fensulfothion, and 9.9 ng/mL for isocarbophos. The accuracy and reliability of the method is further verified by testing the recovery rate of OPs spiked in two different complicated sample matrices (pears and radishes). It is worth mentioning that not only the developed aptamer microarray technology has low sensitivity and a broad spectrum, but it also allows for high-throughput and rapid analysis of a variety OPs, which overcomes some of the shortcomings of other OP detection methods.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Praguicidas , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Compostos Organofosforados/análise , Praguicidas/análise , Reprodutibilidade dos Testes , Espectrometria de Fluorescência/métodos
4.
Molecules ; 27(17)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36080490

RESUMO

The Systematic Evolution of Ligands by EXponential enrichment (SELEX) is conventionally an effective method to identify aptamers, which are oligonucleotide sequences with desired properties to recognize targets specifically and sensitively. However, there are some inherent limitations, e.g., the loss of potential high-affinity sequences during biased iterative PCR enrichment processes and the limited structural diversity of the initial library, which seriously restrict their real-world applications. To overcome these limitations, the in silico base mutagenesis post-SELEX strategy based on the low Gibbs free energy (ΔG) and genetic algorithm was developed for the optimization of the interferon-gamma aptamer (B1-4). In the process of evolution, new sequences were created and the aptamer candidates with low ΔG values and advanced structures were produced. After five rounds of selection, systematic studies revealed that the affinity of the newly developed evolutionary aptamer (M5-5) was roughly 10-fold higher than that of the parent aptamer (B1-4), and an aptasensor detection system with a limit-of-detection (LOD) value of 3.17 nM was established based on the evolutionary aptamer. The proposed approach provided an efficient strategy to improve the aptamer with low energy and a high binding ability, and the good analytical utility thereof.


Assuntos
Aptâmeros de Nucleotídeos , Técnica de Seleção de Aptâmeros , Aptâmeros de Nucleotídeos/química , Interferon gama/genética , Ligantes , Mutagênese , Técnica de Seleção de Aptâmeros/métodos
5.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 38(3): 434-446, 2021 Jun 25.
Artigo em Zh | MEDLINE | ID: mdl-34180188

RESUMO

Motor imagery (MI) is an important paradigm of driving brain computer interface (BCI). However, MI is not easy to control or acquire, and the performance of MI-BCI depends heavily on the performance of the subjects' MI. Therefore, the correct execution of MI mental activities, ability evaluation and improvement methods play important and even critical roles in the improvement and application of MI-BCI system's performance. However, in the research and development of MI-BCI, the existing researches mainly focus on the decoding algorithm of MI, but do not pay enough attention to the above three aspects of MI mental activities. In this paper, these problems of MI-BCI are discussed in detail, and it is pointed out that the subjects tend to use visual motor imagery as kinesthetic motor imagery. In the future, we need to develop some objective, quantitatively visualized MI ability evaluation methods, and develop some effective and less time-consumption training methods to improve MI ability. It is also necessary to solve the differences and commonness of MI problems between and within individuals and MI-BCI illiteracy to a certain extent.


Assuntos
Interfaces Cérebro-Computador , Algoritmos , Eletroencefalografia , Humanos , Imagens, Psicoterapia , Imaginação
6.
Anal Biochem ; 594: 113591, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31968209

RESUMO

Exosomes are Extracellular Vesicles (EV) that own unique structural features and functions and have gradually become the hot research spot in recent years. The tumor-derived exosomes contain various types of useful biological information, and medical identification of exosomes relied on the specific characterization of membrane surface proteins. In this study, in order to rapidly identify non-small cell lung cancer (NSCLC)-derived exosomes, based on an aptamer against CD63 protein on exosome membrane, a low cost lateral flow aptamer assay (LFAA) test strip using nanogold particles as visualization probes was successfully developed for facile identification of A549 exosomes isolated from human lung carcinoma cells diluted from 6.4 × 109 particles/mL herein.


Assuntos
Aptâmeros de Nucleotídeos/química , Bioensaio/métodos , Exossomos/química , Tetraspanina 30/química , Nanomedicina Teranóstica/métodos , Células A549 , Carcinoma Pulmonar de Células não Pequenas/química , Ouro/química , Humanos , Neoplasias Pulmonares/química , Nanopartículas Metálicas/química
7.
Int J Mol Sci ; 20(20)2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31614967

RESUMO

Rubber particles are a specific organelle for natural rubber biosynthesis (NRB) and storage. Ethylene can significantly improve rubber latex production by increasing the generation of small rubber particles (SRPs), regulating protein accumulation, and activating many enzyme activities. We conducted a quantitative proteomics study of different SRPs upon ethylene stimulation by differential in-gel electrophoresis (DIGE) and using isobaric tags for relative and absolute quantification (iTRAQ) methods. In DIGE, 79 differentially accumulated proteins (DAPs) were determined as ethylene responsive proteins. Our results show that the abundance of many NRB-related proteins has been sharply induced upon ethylene stimulation. Among them, 23 proteins were identified as rubber elongation factor (REF) and small rubber particle protein (SRPP) family members, including 16 REF and 7 SRPP isoforms. Then, 138 unique phosphorylated peptides, containing 129 phosphorylated amino acids from the 64 REF/SRPP family members, were identified, and most serine and threonine were phosphorylated. Furthermore, we identified 226 DAPs from more than 2000 SRP proteins by iTRAQ. Integrative analysis revealed that almost all NRB-related proteins can be detected in SRPs, and many proteins are positively responsive to ethylene stimulation. These results indicate that ethylene may stimulate latex production by regulating the accumulation of some key proteins. The phosphorylation modification of REF and SRPP isoforms might be crucial for NRB, and SRP may act as a complex natural rubber biosynthetic machine.


Assuntos
Antígenos de Plantas/genética , Hevea/genética , Látex/biossíntese , Proteínas de Plantas/genética , Sequência de Aminoácidos , Etilenos/metabolismo , Hevea/metabolismo , Proteoma/genética , Proteômica , Borracha/química , Borracha/metabolismo
8.
Mass Spectrom Rev ; 36(2): 161-187, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-25975720

RESUMO

Direct analysis in real time (DART) represents a new generation of ion source which is used for rapid ionization of small molecules under ambient conditions. The combination of DART and various mass spectrometers allows analyzing multiple food samples with simple or no sample treatment, or in conjunction with prevailing protocolized sample preparation methods. Abundant applications by DART-MS have been reviewed in this paper. The DART-MS strategy applied to food supply chain (FSC), including production, processing, and storage and transportation, provides a comprehensive solution to various food components, contaminants, authenticity, and traceability. Additionally, typical applications available in food analysis by other ambient ionization mass spectrometers were summarized, and fundamentals mainly including mechanisms, devices, and parameters were discussed as well. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:161-187, 2017.


Assuntos
Análise de Alimentos/métodos , Qualidade dos Alimentos , Espectrometria de Massas/métodos , Animais , Desenho de Equipamento , Análise de Alimentos/instrumentação , Manipulação de Alimentos/instrumentação , Manipulação de Alimentos/métodos , Abastecimento de Alimentos , Humanos , Espectrometria de Massas/instrumentação
9.
Electrophoresis ; 38(2): 368-371, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27189507

RESUMO

Herein, a competitive luminol chemiluminescence immunosensor based on a microfluidic chip was developed to detect ractopamine (RCT) both in phosphate buffer and swine urine samples. The immunosensor can provide a liner range of 0.5-40 ng/mL and a high sensitivity with a limit of detection of 0.97 ng/mL for RCT detection in swine urine. Good rates of recovery in negative swine urine samples were achieved over the RCT concentration ranging from 0.5 to 40 ng/mL. The proposed method offered a promising analytical scheme for the on-site determination of RCT.


Assuntos
Imunoensaio/métodos , Medições Luminescentes/métodos , Luminol/química , Técnicas Analíticas Microfluídicas/métodos , Fenetilaminas/urina , Animais , Luminol/análise , Suínos
10.
Sensors (Basel) ; 17(3)2017 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-28300766

RESUMO

Ractopamine (RCT) is banned for use in animals in many countries, and it is urgent to develop efficient methods for specific and sensitive RCT detection. A label-free indirect competitive surface plasmon resonance (SPR) immunosensor was first developed with a primary antibody herein and then improved by a secondary antibody for the detection of RCT residue in swine urine. Meanwhile, a pre-incubation process of RCT and the primary antibody was performed to further improve the sensitivity. With all the key parameters optimized, the improved immunosenor can attain a linear range of 0.3-32 ng/mL and a limit of detection (LOD) of 0.09 ng/mL for RCT detection with high specificity. Furthermore, the improved label-free SPR immunosenor was compared thoroughly with a conventional enzyme-linked immunosorbent assay (ELISA). The SPR immunosensor showed advantages over the ELISA in terms of LOD, reagent consumption, analysis time, experiment automation, and so on. The SPR immunosensor can be used as potential method for real-time monitoring and screening of RCT residue in swine urine or other samples. In addition, the design using antibody pairs for biosensor development can be further referred to for other small molecule detection.


Assuntos
Ensaio de Imunoadsorção Enzimática , Animais , Técnicas Biossensoriais , Fenetilaminas , Ressonância de Plasmônio de Superfície , Suínos
11.
Anal Biochem ; 499: 34-42, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26844871

RESUMO

Commercial natural rubber is traditionally supplied by Hevea brasiliensis, but now there is a big energy problem because of the limited resource and increasing demand. Intensive study of key rubber-related substances is urgently needed for further research of in vitro biosynthesis of natural rubber. Natural rubber is biosynthesized on the surface of rubber particles. A membrane protein called small rubber particle protein (SRPP) is a key protein associated closely with rubber biosynthesis; however, SRPP in different plants has been only qualitatively studied, and there are no quantitative reports so far. In this work, H. brasiliensis was chosen as a model plant. The microscopic distribution of SRPP on the rubber particles during the washing process was investigated by transmission electron microscopy-immunogold labeling. A label-free surface plasmon resonance (SPR) immunosensor was developed to quantify SRPP in H. brasiliensis for the first time. The immunosensor was then used to rapidly detect and analyze SRPP in dandelions and prickly lettuce latex samples. The label-free SPR immunosensor can be a desirable tool for rapid quantitation of the membrane protein SRPP, with excellent assay efficiency, high sensitivity, and high specificity. The method lays the foundation for further study of the functional relationship between SRPP and natural rubber content.


Assuntos
Antígenos de Plantas/análise , Hevea/química , Látex/química , Proteínas de Plantas/análise , Antígenos de Plantas/metabolismo , Hevea/metabolismo , Imunoensaio , Látex/metabolismo , Microscopia Eletrônica de Transmissão , Proteínas de Plantas/metabolismo , Ressonância de Plasmônio de Superfície
12.
Crit Rev Food Sci Nutr ; 54(12): 1548-61, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24580557

RESUMO

Accompanied by industrial globalization, rapid urbanization, and population increment, mass production and staple trading for food consumption are upsoaring continuously, foodborne disease resulted from various food safety issues is currently a crucial public health concern worldwide, which has not only created a great burden on both economy and society, but also greatly threatened the sustainability of mankind's livelihood and human reproduction. In order to better ensure food safety and thus effectively curb the occurrence of foodborne diseases, the development and evolving of inspection strategies are indispensable measures for quality assurance and conformity assessment. Nowadays, as complementary measures to and with advantageous merits over classic analytical methods, highly specific and selective aptamer-based assays have found their increasingly important roles in various domains of food analysis. This critical review summarizes the advantages of aptamer as compared with antibody, introduces important evolving variants of systematic evolution of ligands by exponential enrichment (SELEX), and presents an overview of potential aptamer applications for food safety.


Assuntos
Inocuidade dos Alimentos/métodos , Técnica de Seleção de Aptâmeros/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Humanos , Saúde Pública
13.
Int J Biol Macromol ; 274(Pt 2): 133444, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38936584

RESUMO

Food allergens elicit abnormal immune system responses among allergic individuals and sensitive detection for allergenic ingredient is greatly significant. To address this need, a novel fluorescent aptasensor, assisted by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), have been developed for food allergens. In this study, aptamer offers distinctive recognition capabilities in binding specific targets, while CRISPR-associated-12a protein (Cas12a) holds precise cis-cleavage for cutting fluorescent signal probes. Notably, the utilization of Cas12a cis-cleavage activity, rather than trans-cleavage, eliminates the necessity for additional fluorescent probes, thus reducing interference between substances and enhancing sensitivity. Throughout the process, complementary DNA (cDNA) plays a crucial dual role in target recognition conversion and signal presentation, representing a key challenge and innovative aspect of this study. To evaluate the performance of the aptasensor, lysozyme (LYS) is employed as a representative model target of food allergens. Under optimal conditions, the developed aptasensor could achieve an exceptional low limit of detection (LOD) of 6.10 pM with a dynamic detection range of 10 pM-320 pM. The aptasensor demonstrates high selectivity and great recovery rates. This strategy yields promising outcomes, holding the potential to serve as a valuable reference for various food allergens detection.


Assuntos
Alérgenos , Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Sistemas CRISPR-Cas , Alérgenos/análise , Aptâmeros de Nucleotídeos/química , Proteínas de Bactérias/química , Técnicas Biossensoriais/métodos , Proteínas Associadas a CRISPR/química , Endodesoxirribonucleases/química , Corantes Fluorescentes/química , Limite de Detecção , Muramidase/química
14.
Front Cell Dev Biol ; 11: 1183163, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37377731

RESUMO

Background: Despite great efforts to develop microvascular bone chips in previous studies, current bone chips still lacked multi-component of human-derived cells close to human bone tissue. Bone microvascular endothelial cells (BMECs) were demonstrated to be closely related to the glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH). Tumor necrosis factor-alpha (TNF-α) aptamer has been proved to bind to its receptor and block cascade activities. Objective: There are two main objectives in this study: 1) to establish a multi-component bone-on-a-chip within the microfluidic system in vitro, 2) to explore the therapeutic potential of TNF-α aptamer on BMECs in the GC-induced ONFH model. Methods: Histological features of clinical samples were analyzed before BMECs isolation. The functional bone-on-a-chip consists of the vascular channel, stromal channel and structure channel. GC-induced ONFH model was established based on the multi-component of human-derived cells. Truncation and dimerization were performed on a previously reported DNA aptamer (VR11). BMECs apoptosis, cytoskeleton and angiogenesis status in the ONFH model were observed by the TUNEL staining and confocal microscope. Results: The multi-component of BMECs, human embryonic lung fibroblasts and hydroxyapatite were cultured within the microfluidic bone-on-a-chip. TNF-α was found up-regulated in the necrotic regions of femoral heads in clinical samples and similar results were re-confirmed in the ONFH model established in the microfluidic platform by detecting cell metabolites. Molecular docking simulations indicated that the truncated TNF-α aptamer could improve the aptamer-protein interactions. Further results from the TUNEL staining and confocal microscopy showed that the truncated aptamer could protect BMECs from apoptosis and alleviate GC-induced damages to cytoskeleton and vascularization. Conclusion: In summary, a microfluidic multi-component bone-on-a-chip was established with 'off-chip' analysis of cell metabolism. GC-induced ONFH model was achieved based on the platform. Our findings provided initial evidence on the possible potentials of TNF-α aptamer as a new type of TNF-α inhibitor for patients with ONFH.

15.
J Biotechnol ; 361: 80-88, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36435303

RESUMO

A convenient and nonradioactive method for quantifying in vitro NR biosynthesis is presented that is based upon the quantitation of substrate depletion by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). NR oligomers could be in vitro biosynthesized with the enzyme source from Hevea brasiliensis (Hevea) or Taraxacum kok-saghyz (TKS) by exogenous monomers (IPP) and initiators (FPP). The IPP incorporation rate and FPP consumption rate were 62.24% and 51.14% respectively when the washed rubber particles (WRP) of Hevea was the enzyme source. The IPP incorporation rate and the FPP consumption rate were 74.49% and 95.90% respectively when the sediment bottom fraction (BF) of Hevea was the enzyme source. The in vitro NR biosynthesis can be divided into two stages:(1) the initiation reaction of FPP, which occurs more in BF, and (2) the growth reaction of IPP, which occurs more in WRP. In addition, the IPP incorporation and FPP consumption rates were 59.39% and 34.15% respectively when the BF of TKS was selected as an enzyme source.


Assuntos
Espectrometria de Massas em Tandem
16.
Foods ; 12(17)2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37685137

RESUMO

Selenium-enriched rapeseed (SER) is an emerging oil seed. Roasting is beneficial in improving oil yield and promoting the release of micronutrients into SER oil, but high temperatures and dry air lead to selenium loss and fatty acid degradation in SER. To minimize the selenium loss and improve the SER oil quality, this study investigated the effects of vacuum (VC) roasting (90-170 °C for 30 min) on the SER selenium content, Maillard reaction products, oxidative stability, and physicochemical properties of SER oil, with conventional dry air (DA) roasting as the control. The results showed that the selenium loss in VC-roasted SER meals increased from 7.17 to 19.76% (90-170 °C for 30 min), which was 47.13 to 80.48% of that in DA-roasted SER meals, while no selenium was detected in the SER oils. Compared to DA roasting, VC roasting (90-170 °C for 30 min) reduced lipid oxidation products (LOPs), Maillard reaction products (MRPs), and benzo[a]pyrene contents, and increased carotenoids, unsaturated fatty acid contents, reaching a maximum oil yield of 35.58% at a lower temperature (130 °C for 30 min). Selenium contents exhibited a highly significant negative correlation with MRPs and LOPs (p ≤ 0.005). The VC roasting retarded selenium loss and improved SER oil quality compared to conventional DA roasting.

17.
Anal Bioanal Chem ; 402(3): 1011-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22134493

RESUMO

Owing to the well-established nanochannel fabrication technology in 2D nanoscales with high resolution, reproducibility, and flexibility, glass is the leading, ideal, and unsubstitutable material for the fabrication of nanofluidic chips. However, high temperature (~1,000 °C) and a vacuum condition are usually required in the conventional fusion bonding process, unfortunately impeding the nanofluidic applications and even the development of the whole field of nanofluidics. We present a direct bonding of fused silica glass nanofluidic chips at low temperature, around 200 °C in ambient air, through a two-step plasma surface activation process which consists of an O(2) reactive ion etching plasma treatment followed by a nitrogen microwave radical activation. The low-temperature bonded glass nanofluidic chips not only had high bonding strength but also could work continuously without leakage during liquid introduction driven by air pressure even at 450 kPa, a very high pressure which can meet the requirements of most nanofluidic operations. Owing to the mild conditions required in the bonding process, the method has the potential to allow the integration of a range of functional elements into nanofluidic chips during manufacture, which is nearly impossible in the conventional high-temperature fusion bonding process. Therefore, we believe that the developed low-temperature bonding would be very useful and contribute to the field of nanofluidics.


Assuntos
Vidro/química , Técnicas Analíticas Microfluídicas/instrumentação , Dióxido de Silício/química , Desenho de Equipamento , Propriedades de Superfície , Temperatura
18.
Environ Sci Pollut Res Int ; 29(24): 36951-36966, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35066841

RESUMO

Reference evapotranspiration ([Formula: see text]) is an important indicator for hydrometeorological change, which integrates atmospheric and surface conditions, and its downward trends have been reported in many regions over the past several decades. Cold regions constitute an important ecological barrier in China; however, few studies focus on change in [Formula: see text] in cold regions. Especially in the cold region of northeast China (CRNEC), as one of the national strategic grain bases, understanding spatial-temporal variations of [Formula: see text] is important for agriculture water management and ecological protection. This study selected the observations at 113 national meteorological stations located in CRNEC and evaluated the trends of [Formula: see text] and their driving factors from 1961 to 2017. Results indicate that annual [Formula: see text] increases from the northeast to the southwest of CRNEC and has an insignificant decreasing trend in the whole study period, in which 33 stations (29.2%) show significant decreasing trends and only 19 stations (16.8%) show significant increasing trends at the 95% confidence level. An abrupt change in [Formula: see text] data is detected from 1994. Reasons for this abrupt change in [Formula: see text] vary largely over the study areas. Analysis shows that wind speed and minimum air temperature are the two major factors that control the change of [Formula: see text] before 1994. It also shows that wind speed and actual vapor pressure are the two major controlling factors after 1994. We also found that [Formula: see text] shows a certain correlation with Pacific Decadal Oscillation and Western Pacific Index, but there is a significant correlation between meteorological factors and teleconnection factors related to [Formula: see text]. These findings will promote agricultural water management and improve water ecological protection in the CRNEC. We investigated changes in reference evapotranspiration relationships with atmospheric circulation and its attributions over the cold regions in northeast China during 1961 ~ 2017. The results indicate that the wind speed and minimum air temperature are the two major factors that control the change of ET0 before 1994, and wind speed and actual vapor pressure are the two major controlling factors after 1994. We also found that ET0 shows a certain correlation with Western Pacific Index in the whole period.


Assuntos
Produtos Agrícolas , Transpiração Vegetal , China , Meteorologia , Temperatura , Água
19.
Polymers (Basel) ; 14(21)2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-36365625

RESUMO

PTFE/Al reactive material is an energetic material that releases energy under impact conditions, resulting in a wide range of application prospects. In order to improve its damage ability-considering the higher heat of the reaction per unit mass when Ni2O3 is involved in the aluminothermic reaction-we designed and studied PTFE/Al/Ni2O3, a reaction material based on polytetrafluoroethylene (PTFE). We also designed two other kinds (PTFE/Al, PTFE/Al/CuO) for comparative study, with the mass fraction of the metal oxides added at 10%, 20%, and 30%, respectively. The quasi-static compression properties and impact initiation behavior of the material were investigated by a universal material testing machine and a drop hammer test. The reaction process of different materials under a high strain rate was recorded using a high-speed camera. The results show that with the increase in Ni2O3 content, the strength of the PTFE/Al/Ni2O3 reactive material shows an increasing trend followed by a decreasing trend. Among the three reactive materials, when the content of Al/Ni2O3 reaches 30 wt.%, the reaction duration is the longest (at 4 ms) and the reaction fireball is the largest. The addition of Ni2O3 is helpful to improve the reactivity and reaction duration of the PTEF/Al reactive material.

20.
Anal Chim Acta ; 1155: 338345, 2021 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-33766318

RESUMO

Nowadays, contamination of various mycotoxins in crops and their products exposes increasing risks to human health. Efficient determination methods are urgently needed. Herein, a bifunctional aptamer and a simple aptasensor based on microscale thermophoresis assay (MST) were constructed for the first time for simultaneous determination of two mycotoxins, i.e. zearalenone (ZEN) and ochratoxin A (OTA). The bifunctional aptamer was engineered by splicing a ZEN aptamer and an OTA aptamer with a linker according to the structure analysis of aptamers. The binding mechanism of the bifunctional aptamer to ZEN and OTA were revealed basing on the molecular docking studies. The MST assay proved that the bifunctional aptamer showed high affinity and specificity towards ZEN and OTA. Furthermore, a bifunctional aptamer-based MST-aptasensor was developed for simultaneous detection of ZEN and OTA in corn oil sample. The MST-aptasensor provided a limit of detection (LOD) of 0.12 nM, with satisfactory recoveries of 93.31-104.19% and excellent selectivity, indicating that the bifunctional aptamer and MST-aptasensor had great potential in practical applications.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Ocratoxinas , Zearalenona , Contaminação de Alimentos/análise , Humanos , Limite de Detecção , Simulação de Acoplamento Molecular , Ocratoxinas/análise , Zearalenona/análise
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