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1.
Epilepsy Behav ; 157: 109868, 2024 May 31.
Article in English | MEDLINE | ID: mdl-38823075

ABSTRACT

BACKGROUND: Previous research has demonstrated that neuroinflammation is a key element in the progress of epilepsy. Nevertheless, it is currently unidentified which inflammatory factors and proteins increase or decrease the risk of epilepsy. METHODS: We adopted Mendelian randomization techniques to explore the causal relationship between circulating inflammatory factors and proteins and various epilepsy. Our principal approach was inverse variance weighting, supplemented by several sensitivity analyses to guarantee the robustness of our findings. RESULTS: Studies have identified associations between epilepsy and specific inflammatory factors and proteins: three inflammatory factors and six proteins are linked to epilepsy in general; one inflammatory factor and four proteins are associated with focal epilepsy with no documented lesions; two inflammatory factors and three proteins are related to focal epilepsy, excluding cases with hippocampal sclerosis; two inflammatory factors and two proteins are connected to juvenile myoclonic epilepsy; two inflammatory factors and five proteins are linked to juvenile absence epilepsy; four inflammatory proteins are associated with childhood absence epilepsy; two inflammatory factors are related to focal epilepsy overall; two inflammatory factors and two proteins are connected to generalized epilepsy; and two inflammatory proteins are linked to generalized epilepsy with tonic-clonic seizures. Additionally, six inflammatory factors may play a downstream role in focal epilepsy. CONCLUSION: Our study uncovers various inflammatory factors and proteins that influence the risk of epilepsy, offering instructive insights to the diagnosis and therapy of the condition.

2.
Sci Total Environ ; 918: 170672, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38316306

ABSTRACT

Aminium ions, as crucial alkaline components within fine atmospheric particles, have a notable influence on new particle formation and haze occurrence. Their concentrations within coastal atmosphere depict considerable variation due to the interplay of distinctive marine and terrestrial sources, further complicated by dynamic meteorological conditions. This study conducted a comprehensive examination of aminiums ions concentrations, with a particular focus on methylaminium (MMAH+), dimethylaminium (DMAH+), trimethylaminium (TMAH+), and triethylaminium (TEAH+) within PM2.5, over varying seasons (summer, autumn, and winter of 2019 and summer of 2021), at an urban site in the coastal megacity of Qingdao, Northern China. The investigations revealed that the total concentration of particulate aminium ions (∑Aminium) was 21.6 ± 23.6 ng/m3, exhibiting higher values in the autumn and winter compared to the two summer periods. Considering diurnal variations during autumn and winter, concentrations of particulate aminium ions (excluding TEAH+) exhibited a slight increase during the day compared to night, with a notable peak during the morning hours. However, it was not the case for TEAH+, which was argued to be readily oxidized by ambient oxidants in the afternoon. Additionally, the ∑Aminium within the summer demonstrated markedly elevated levels during the day compared to night, potentially attributed to daytime sea fog associated with sea-land breeze interactions. Positive matrix factorization results indicate terrestrial anthropogenic emissions, including vehicle emission mixed with road dust and primary pollution, as the primary sources of MMAH+ and DMAH+. Conversely, TMAH+ was predominantly emitted from agricultural and marine sources. With the dominance of sea breeze in summer, TMAH+ was identified as a primary marine emission correlated with sea salt, while MMAH+, DMAH+, and TEAH+ were postulated to undergo secondary formation. Furthermore, a notable inverse correlation was observed between TMAH+ and methanesulfonate in PM2.5, consistent with dynamic emissions of sulfur-content and nitrogen-content gases reported in the literature.

3.
Sci Total Environ ; 918: 170493, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38307263

ABSTRACT

The long-range transport of dust aerosols plays a crucial role in biogeochemical cycling, and dust deposition is an important source of nutrients for marine phytoplankton growth. To study the impact of COVID-19 emission reduction on dust aerosols and marine chlorophyll-a (Chl-a) concentration, we selected two similar dust processes from the COVID-19 period (10-15 March 2020) and the non-COVID-19 period (15-20 March 2019) using the Euclidean distance calculation method in combination with the HYSPLIT model and multiple satellite data. During the non-COVID-19 period, the proportion of dust was 6.68 %, approximately half that of the COVID-19 period. Meanwhile, the proportion of polluted dust during the non-COVID-19 period was 4.95 %, which was more than tenfold compared to the COVID-19 period. Furthermore, noticeable discrepancies in Chl-a concentration were observed between the two periods. In the non-COVID-19 period, the maximum daily deposition of dust aerosols can reach 16.23 mg/m2, resulting in a 39-85 % increase in Chl-a concentration. However, during COVID-19 period, the maximum daily dust deposition can reach 33.33 mg/m2, while the increase in Chl-a concentration was <30 %. This conclusion suggests that reductions in anthropogenic emissions during the COVID-19 period have influenced the nutrient content of dust aerosols, resulting in a lesser impact on Chl-a concentrations in the ocean.


Subject(s)
Air Pollutants , COVID-19 , Humans , Dust/analysis , Chlorophyll A , Respiratory Aerosols and Droplets , Chlorophyll , Air Pollutants/analysis , Environmental Monitoring
4.
Talanta ; 271: 125679, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38245958

ABSTRACT

The development of efficient, rapid, portable, and accurate analysis of veterinary drug residues in food matrices is in great demand for food safety assessment. Here, we have developed a smartphone-integrated platform for fluorometric quantification of metronidazole (MNZ) residues and constructed a sensor array for discrimination of different nitroimidazole antibiotics (NIIMs). Multicolor CDs (B-CDs, C-CDs, Y-CDs, and R-CD) were prepared and showed different fluorescence response to MNZ. The fluorescence of C-CDs was quenched Because of the inner filter effect (IFE) between the C-CDs and MNZ, while that of R-CDs was enhanced due to the passivation of surface defects by MNZ. Based on the response pattern, the fluorometric quantification of MNZ based on the fluorescence images of C-CD + R-CD system (R/G values) was achieved with a low detection limit of 0.45 µM. By designing a smartphone-integrated platform, the analysis can be completed within 20 min. In addition, a fluorescence sensor array based C-CDs and R-CDs was also developed. The unique fingerprint of each NIIMs was obtained by linear discriminant analysis (LDA) of the response patterns, indicating an effective discrimination of five NIIMs. Moreover, the platform was used for quantification of MNZ in food samples and the recoveries were within 84.0-106.3 % with relative standard deviations 1.2-10.2 %. Therefore, the proposed method shows great potential as a universal platform for rapid detection of veterinary drug residues.


Subject(s)
Nitroimidazoles , Quantum Dots , Veterinary Drugs , Anti-Bacterial Agents , Carbon , Fluorometry , Fluorescent Dyes , Spectrometry, Fluorescence
5.
Heliyon ; 10(1): e23940, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38223707

ABSTRACT

Normal pressure hydrocephalus (NPH) is a prevalent type of hydrocephalus, including secondary normal pressure hydrocephalus (SNPH) and idiopathic normal pressure hydrocephalus (INPH). However, its clinical diagnosis and pathological mechanism are still unclear. Leucine-rich α-2 glycoprotein (LRG) is involved in various human diseases, including cancer, diabetes, cardiovascular disease, and nervous system diseases. Now the physiological mechanism of LRG is still being explored. According to the current research results on LRG, we found that the agency of LRG has much to do with the known pathological process of NPH. This review focuses on analyzing the LRG signaling pathways and the pathological mechanism of NPH. According to the collected literature evidence, we speculated that LRG probably be involved in the pathological process of NPH. Finally, based on the mechanism of LRG and NPH, we also summarized the evidence of molecular targeted therapies for future research and clinical application.

6.
Mol Med Rep ; 29(1)2024 Jan.
Article in English | MEDLINE | ID: mdl-37997799

ABSTRACT

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the control data in Fig. 2B and C on p. 7332, showing immunofluorescence and migration assay experiments respectively, were strikingly similar to data appearing in different form in another article which was written by different authors at different research institutes [Tian L, Shen D, Li X, Shan X, Wang X, Yan Q and Liu J: Ginsenoside Rg3 inhibits epithelial­mesenchymal transition (EMT) and invasion of lung cancer by down­regulating FUT4. Oncotarget 7: 1619­1632, 2016]. Owing to the fact that the contentious data in the above article had already been published prior to its submission to Molecular Medicine Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 16: 7329­7336, 2017; DOI: 10.3892/mmr.2017.7517].

7.
Zhongguo Zhong Yao Za Zhi ; 48(22): 5977-5984, 2023 Nov.
Article in Chinese | MEDLINE | ID: mdl-38114203

ABSTRACT

Plant-derived exosome-like nanoparticles(PELNs) are a class of membranous vesicles with diameters approximately ranging from 30 to 300 nm, isolated from plant tissues. They contain components such as proteins, lipids, and nucleic acids. PELNs play an important role in the metabolism of plant substances and immune defense, and can also cross-regulate the physiological activities of fungi and animal cells, showing significant potential applications. In recent years, research on PELNs has significantly increased, highlighting three main issues:(1) the mixed sources of plant materials for PELNs;(2) the lack of a unified system for isolating and characterizing PELNs;(3) the urgent need to elucidate the molecular mechanisms underlying the cross-regulation of biological functions by PELNs. This article focused on these concerns. It began by summarizing the biological origin and composition of PELNs, discussing the techniques for isolating and characterizing PELNs, and analyzing their biomedical applications and potential future research directions., aiming to promote the establishment of standardized research protocols for PELNs and provide theoretical references for in-depth exploration of the mechanisms underlying PELNs' cross-regulatory effects.


Subject(s)
Exosomes , Nanoparticles , Nucleic Acids , Animals , Exosomes/metabolism , Proteins/metabolism , Plants/metabolism
8.
Front Endocrinol (Lausanne) ; 14: 1216817, 2023.
Article in English | MEDLINE | ID: mdl-37780610

ABSTRACT

Pituitary adenoma (PA) is the third most common central nervous system tumor originating from the anterior pituitary, but its pathogenesis remains unclear. The Wnt signaling pathway is a conserved pathway involved in cell proliferation, Self-renewal of stem cells, and cell differentiation. It is related to the occurrence of various tumors, including PA. This article reviews the latest developments in Wnt pathway inhibitors and pathway-targeted drugs. It discusses the possibility of combining Wnt pathway inhibitors with immunotherapy to provide a theoretical basis for the combined treatment of PA.


Subject(s)
Pituitary Neoplasms , Wnt Signaling Pathway , Humans , Pituitary Neoplasms/pathology , Stem Cells/metabolism , Cell Differentiation
10.
Heredity (Edinb) ; 131(3): 179-188, 2023 09.
Article in English | MEDLINE | ID: mdl-37402824

ABSTRACT

The classical model of concerted evolution states that hundreds to thousands of ribosomal DNA (rDNA) units undergo homogenization, making the multiple copies of the individual units more uniform across the genome than would be expected given mutation frequencies and gene redundancy. While the universality of this over 50-year-old model has been confirmed in a range of organisms, advanced high throughput sequencing techniques have also revealed that rDNA homogenization in many organisms is partial and, in rare cases, even apparently failing. The potential underpinning processes leading to unexpected intragenomic variation have been discussed in a number of studies, but a comprehensive understanding remains to be determined. In this work, we summarize information on variation or polymorphisms in rDNAs across a wide range of taxa amongst animals, fungi, plants, and protists. We discuss the definition and description of concerted evolution and describe whether incomplete concerted evolution of rDNAs predominantly affects coding or non-coding regions of rDNA units and if it leads to the formation of pseudogenes or not. We also discuss the factors contributing to rDNA variation, such as interspecific hybridization, meiotic cycles, rDNA expression status, genome size, and the activity of effector genes involved in genetic recombination, epigenetic modifications, and DNA editing. Finally, we argue that a combination of approaches is needed to target genetic and epigenetic phenomena influencing incomplete concerted evolution, to give a comprehensive understanding of the evolution and functional consequences of intragenomic variation in rDNA.


Subject(s)
Genetic Variation , Polymorphism, Genetic , Animals , DNA, Ribosomal/genetics , Mutation , Fungi/genetics , Evolution, Molecular , Phylogeny
11.
Zhongguo Yi Liao Qi Xie Za Zhi ; 47(3): 242-246, 2023 May 30.
Article in Chinese | MEDLINE | ID: mdl-37288621

ABSTRACT

As a new energy source for atrial fibrillation ablation, electric pulse ablation has higher tissue selectivity and biosafety, so it has a great application prospect. At present, there is very limited research on multi-electrode simulated ablation of histological electrical pulse. In this study, a circular multi-electrode ablation model of pulmonary vein will be built on COMSOL5.5 platform for simulation research. The results show that when the voltage amplitude reaches about 900 V, it can make some positions achieve transmural ablation, and the depth of continuous ablation area formed can reach 3 mm when the voltage amplitude reaches 1 200 V. When the distance between catheter electrode and myocardial tissue is increased to 2 mm, a voltage of at least 2 000 V is required to make the depth of continuous ablation area reach 3 mm. Through the simulation of electric pulse ablation with ring electrode, the research results of this project can provide reference for the voltage selection in the clinical application of electric pulse ablation.


Subject(s)
Atrial Fibrillation , Catheter Ablation , Humans , Heart Rate , Atrial Fibrillation/surgery , Electrodes , Electricity
12.
Environ Sci Technol ; 57(28): 10284-10294, 2023 07 18.
Article in English | MEDLINE | ID: mdl-37357464

ABSTRACT

Organosulfates (OSs) could be potentially important compounds in marine organic aerosols, while their formation in marine atmospheres is far from clear due to a lack of cruise observations. In this work, shipboard atmospheric observations were conducted over the Yellow Sea and Bohai Sea to investigate the abundance and formation of biogenic isoprene/monoterpene-OSs in marine aerosols. The quantified OSs and NOSs accounted for 0.04-6.9% of marine organic aerosols and were 0.07-2.2% of the non-sea-salt (nss) sulfate in terms of sulfur content. Isoprene-related (nitrooxy-)OSs occupied 27-87% of the total quantified OSs, following the abundance order of summer > autumn > spring or winter. This order was driven by the marine phytoplankton biomass and sea surface temperature (SST), which controlled the seawater and atmospheric isoprene concentration levels. Under the severe impacts of anthropogenic pollutants from the East Asia continent in winter, monoterpene nitrooxy-OSs, generated with NOx involved in, increased to 34.4 ± 35.5 ng/m3 and contributed 68% of the quantified (nitrooxy-)OSs. Our results highlight the notable roles of biogenic OSs in marine organic aerosols over regions with high biological activity and high SST. The formation of biogenic OSs and their roles in altering marine aerosol properties calls for elaboration through cruise observations in different marine environments.


Subject(s)
Air Pollutants , Environmental Pollutants , Phytoplankton , Air Pollutants/analysis , Monoterpenes , Aerosols/analysis
13.
Front Genet ; 14: 1138703, 2023.
Article in English | MEDLINE | ID: mdl-36896236

ABSTRACT

Eucommia ulmoides is a famous rubber-producing and medicinal tree species that produces unisexual flowers on separate individuals from the earliest stage of stamen/pistil primordium formation. To explore the genetic regulation pathway of sex in E. ulmoides, comprehensive genome-wide analyses and tissue-/sex-specific transcriptome comparisons of MADS-box transcription factors were performed for the first time in this work. Quantitative real-time PCR technique was employed to further validate the expression of genes that are assigned to floral organ ABCDE model. A total of 66 non-redundant E. ulmoides MADS-box (EuMADS) genes were identified, they were classified into Type I (M-type, 17 genes) and Type II (MIKC, 49 genes). Complex protein-motif composition, exon-intron structure and phytohormone-response cis-elements were detected in MIKC-EuMADS genes. Furthermore, 24 differentially-expressed EuMADS genes (DEGs) between male and female flowers, and two DEGs between male and female leaves were revealed. Amongst the 14 floral organ ABCDE model-related genes, there were 6 (A/B/C/E-class) and 5 (A/D/E-class) genes displayed male- and female-biased expression respectively. In particular, one B-class gene EuMADS39 and one A-class gene EuMADS65 were almost exclusively expressed in male trees, no matter in flower or leaf tissues. Collectively, these results suggested a critical role of MADS-box transcription factors in sex determination of E. ulmoides, which is conducive to decoding the molecular regulation mechanism of sex in E. ulmoides.

14.
Int J Mol Sci ; 23(20)2022 Oct 20.
Article in English | MEDLINE | ID: mdl-36293466

ABSTRACT

Polysiloxanes have attracted considerable attention in biomedical engineering, owing to their inherent properties, including good flexibility and biocompatibility. However, their low mechanical strength limits their application scope. In this study, we synthesized a polysiloxane-based polyurethane by chemical copolymerization. A series of thermoplastic polysiloxane-polyurethanes (Si-TPUs) was synthesized using hydroxyl-terminated polydimethylsiloxane containing two carbamate groups at the tail of the polymer chains 4,4'-dicyclohexylmethane diisocyanate (HMDI) and 1,4-butanediol as raw materials. The effects of the hard-segment content and soft-segment number average molecular weight on the properties of the resulting TPUs were investigated. The prepared HMDI-based Si-TPUs exhibited good microphase separation, excellent mechanical properties, and acceptable repeatable processability. The tensile strength of SiTPU-2K-39 reached 21.5 MPa, which is significantly higher than that of other flexible polysiloxane materials. Moreover, the tensile strength and breaking elongation of SiTPU-2K-39 were maintained at 80.9% and 94.6%, respectively, after three cycles of regeneration. The Si-TPUs prepared in this work may potentially be used in gas separation, medical materials, antifouling coatings, and other applications.


Subject(s)
Polyurethanes , Siloxanes , Polyurethanes/chemistry , Siloxanes/chemistry , Biocompatible Materials/chemistry , Tensile Strength , Polymers/chemistry , Dimethylpolysiloxanes
15.
Plant J ; 112(3): 646-663, 2022 11.
Article in English | MEDLINE | ID: mdl-36065632

ABSTRACT

Simple telomeric repeats composed of six to seven iterating nucleotide units are important sequences typically found at the ends of chromosomes. Here we analyzed their abundance and homogeneity in 42 gymnosperm (29 newly sequenced), 29 angiosperm (one newly sequenced), and eight bryophytes using bioinformatics, conventional cytogenetic and molecular biology approaches to explore their diversity across land plants. We found more than 10 000-fold variation in the amounts of telomeric repeats among the investigated taxa. Repeat abundance was positively correlated with increasing intragenomic sequence heterogeneity and occurrence at non-telomeric positions, but there was no correlation with genome size. The highest abundance/heterogeneity was found in the gymnosperm genus Cycas (Cycadaceae), in which megabase-sized blocks of telomeric repeats (i.e., billions of copies) were identified. Fluorescent in situ hybridization experiments using variant-specific probes revealed canonical Arabidopsis-type telomeric TTTAGGG repeats at chromosome ends, while pericentromeric blocks comprised at least four major telomeric variants with decreasing abundance: TTTAGGG>TTCAGGG >TTTAAGG>TTCAAGG. Such a diversity of repeats was not found in the sister cycad family Zamiaceae or in any other species analyzed. Using immunocytochemistry, we showed that the pericentromeric blocks of telomeric repeats overlapped with histone H3 serine 10 phosphorylation signals. We show that species of Cycas have amplified their telomeric repeats in centromeric and telomeric positions on telocentric chromosomes to extraordinary high levels. The ancestral chromosome number reconstruction suggests their occurrence is unlikely to be the product of ancient Robertsonian chromosome fusions. We speculate as to how the observed chromosome dynamics may be associated with the diversification of cycads.


Subject(s)
Cycadopsida , Magnoliopsida , In Situ Hybridization, Fluorescence , Cycadopsida/genetics , Telomere/genetics , Centromere/genetics , Magnoliopsida/genetics
16.
Front Plant Sci ; 13: 953445, 2022.
Article in English | MEDLINE | ID: mdl-36092432

ABSTRACT

Sex determination in dioecious plants has been broadly and progressively studied with the blooming of genome sequencing and editing techniques. This provides us with a great opportunity to explore the evolution and genetic mechanisms underlining the sex-determining system in dioecious plants. In this study, comprehensively reviewing advances in sex-chromosomes, sex-determining genes, and floral MADS-box genes in dioecious plants, we proposed a convergent model that governs plant dioecy across divergent species using a cascade regulation pathway connecting sex-determining genes and MADS-box genes e.g., B-class genes. We believe that this convergent mechanism of sex determination in dioecious plants will shed light on our understanding of gene regulation and evolution of plant dioecy. Perspectives concerning the evolutionary pathway of plant dioecy are also suggested.

17.
Sci Total Environ ; 851(Pt 2): 158270, 2022 Dec 10.
Article in English | MEDLINE | ID: mdl-36028017

ABSTRACT

The long retention of dust air masses in polluted areas, especially in winter, may efficiently change the physicochemical properties of aerosols, causing additional health and ecological effects. A large-scale haze-to-dust weather event occurred in the North China Plain (NCP) region during the autumn-to-winter transition period in 2018, affecting the coastal city Qingdao several times between Nov. 27th and Dec. 1st. To study the evolution of the pollution process, we analyzed the chemical characteristics of PM2.5 and PM10-2.5 and source apportionments of PM2.5 and PM10, The dust stagnated around NCP and moved out and back to the site, noted as dust swing process, promoting SO42- formation in PM2.5 and NO3- formation in PM10-2.5. Source apportionments were analyzed using the Positive Matrix Factorization (PMF) receptor model and weighted potential source contribution function (WPSCF). Before the dust invasion, Qingdao was influenced by severe haze; waste incineration and coal burning were the major contributors (~80 %) to PM2.5, and the source region was in the southwest of Shandong Province. During the initial dust event, mineral dust and the mixed factor of dust and sea salt were the major contributors (46.0 % of PM2.5 and 86.5 % of PM10). During the polluted dust period, the contributions of regional transported biomass burning (22.3 %), vehicle emissions (20.8 %), and secondary aerosols (33.8 %) to PM2.5 from the Beijing-Tianjin-Hebei region significantly increased. The secondary aerosols source was more regional than that of vehicle emissions and biomass burning and contributed considerably to PM10 (30.8 %) during the dust swing process. Our findings demonstrate that environmental managers should consider the possible adverse effects of winter dust on regional and local pollution.


Subject(s)
Air Pollutants , Dust , Dust/analysis , Vehicle Emissions/analysis , Air Pollutants/analysis , Particulate Matter/analysis , Environmental Monitoring , Aerosols/analysis , Coal/analysis , Seasons , China , Minerals
18.
Article in English | MEDLINE | ID: mdl-35955111

ABSTRACT

The slope stability of large open-pit mines has always been a concern and the analysis of large-scale slope landslides is a focus. However, shallow failure in soft rock slopes also has a serious impact on safe production. The northern slope of Baiyunebo West Mine has many shallow landslides in the final slope, resulting in damage of the maintenance channel of the belt transportation system, which has a serious impact on the safety of production. In order to reduce the shallow failure in weak rock slope, it is necessary to analyze the behavior and characteristics of shallow failure in weak rock. Firstly, the mechanical parameters of the intact rock were obtained by using the exploration data; secondly, through the analysis of blasting-damage range, the distribution characteristics of fractures after the failure of weak rock were obtained. Finally, through theoretical analysis, numerical simulation, surface displacement monitoring and on-site shallow-failure case analysis, the deformation and characteristics of shallow failure of weak rock slope in West Mine were obtained. It was found that the mechanical parameters of rock mass strength on the surface of weak rock slope and the original rock were quite different after mining disturbance. The mode of failure of shallow weak rock slope in the West Mine was creep-cracking; the numerical modelling analysis was carried out by using the assignment method of shallow lithology weakening and gradual change, which is more in line with the deformation characteristics of weak rock slope in West Mine. The lower deformation of the soft rock slope in West Mine is 3-5 times that of the upper deformation. The research results are helpful to understand the influence of blasting on the stability of soft rock slope. At present, West Mine has started to adjust blasting parameters according to the research results, so as to reduce the excessive damage of blasting to rock mass, so the stability of the slope is improved.


Subject(s)
Landslides , Mining , Transportation
19.
Polymers (Basel) ; 14(13)2022 Jul 03.
Article in English | MEDLINE | ID: mdl-35808772

ABSTRACT

A novel and cost-effective method for the fabrication of highly conductive Al/Ag core-shell structured microspheres was proposed and investigated. The oxidative co-deposition of catechol and polyamine was firstly performed to modify the surface of the aluminum microsphere. Then, a two-step electroless plating was conducted to fabricate the Al/Ag microspheres. During the first step of the electroless plating process, the surface of the aluminum microsphere was deposited with silver nanoparticle seeds using n-octylamine and ethylene glycol. Then, during the second step of the electroless plating process, silver particles grew evenly to form a compact silver shell on the surface of aluminum via a silver mirror reaction. According to the scanning electron microscope and energy dispersive X-ray results, a compact and continuous silver layer was successfully generated on the surface of the aluminum. The valence of the sliver on the surface of the aluminum was confirmed to be zero, based on the X-ray photoelectron spectrometer and X-ray diffractometer analyses. As a result, the as-prepared Al/Ag microspheres exhibited a high conductivity of 10,000 S/cm. The Al/Ag/MVQ composite demonstrated low electrical resistivity of 0.0039 Ω·cm and great electromagnetic interference shielding effectiveness at more than 70 dB against the X-band, and this result suggests that the as-prepared composite is a promising conductive and electromagnetic shielding material.

20.
ACS Omega ; 7(8): 6728-6736, 2022 Mar 01.
Article in English | MEDLINE | ID: mdl-35252668

ABSTRACT

The problem of microbial growth on various surfaces has increased concern in society in the context of antibiotic misuse and the spreading of hospital infections. Thus, the development of new, antibiotic-free antibacterial strategies is required to combat bacteria resistant to usual antibiotic treatments. This work reports a new method for producing an antibiotic-free antibacterial halloysite-based nanocomposite with silver nanoparticles and phosphomolybdic acid as biocides, which can be used as components of smart antimicrobial coatings. The composite was characterized by using energy-dispersive X-ray fluorescence spectroscopy and transmission electron microscopy. The release of phosphomolybdic acid from the nanocomposite was studied by using UV-vis spectroscopy. It was shown that the antibiotic-free nanocomposite consisting of halloysite nanotubes decorated with silver nanoparticles loaded with phosphomolybdic acid and treated with calcium chloride possesses broad antibacterial properties, including the complete growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa bacteria at a 0.5 g × L-1 concentration and Acinetobacter baumannii at a 0.25 g × L-1 concentration.

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