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Developing highly effective antibacterial agents is important for a wide range of applications. However, the emergence of multiple antibiotic-resistant bacteria poses a public health ...threat. Many developed agents have limited practical application due to chemical instability, low biocompatibility, and poor long-term antibacterial efficiency. In the following study, we synthesize a synergistic nanocomposite by conjugating quercetin (Qu) and acetylcholine (Ach) to the surface of Se nanoparticles (Qu–Ach@SeNPs). Quercetin has been reported to exhibit a wide range of biological activities related to their antibacterial activity and acetylcholine as a neurotransmitter, which can combine with the receptor on the bacterial cell. Arrows indicate NPs and arrowheads indicate compromised cell walls. The study demonstrated how Qu–Ach@SeNPs exhibit a synergistically enhanced antibacterial performance against the multidrug-resistant superbugs (MDRs) compared to Qu@SeNPs and Ach@SeNPs alone. Qu–Ach@SeNPs are effective against MDRs, such as Methicillin-resistant Staphylococcus aureus (MRSA), at a low dose. The mechanistic studies showed that Qu–Ach@SeNPs attach to the bacterial cell wall, causing irreversible damage to the membrane, and thereby achieving a remarkable synergistic antibacterial effect to inhibit MRSA. The findings suggested that the synergistic properties of quercetin and acetylcholine enhance the antibacterial activity of SeNPs. In this way, Qu–Ach@SeNPs comprise a new class of inorganic nano-antibacterial agents that can be used as useful applications in biomedical devices.
The Qu–Ach@SeNPs have low cytotoxicity when tested on normal human cells in vitro. Qu–Ach@SeNPs are effective against MDRs, such as Methicillin-resistant S. aureus (MRSA), at a low dose. Importantly, Qu–Ach@SeNPs showed no emergence of resistance. These results suggest that Qu–Ach@SeNPs have excellent antibacterial activities. These agents can serve as good antibacterial agents against superbugs. Our data suggest that these antibacterial agents may have widespread application in the field of medicine for combating infectious diseases caused by MDRs, as well as other infectious diseases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Upon release into the aquatic environment, the surface of microplastics (MPs) can be readily colonized by biofilms, which may enhance the adsorption of contaminants. In this study, industrial-grade ...polystyrene (PS) of about 4 mm in size (MP4000–1), food-grade PS of about 4 mm in size (MP4000–2), and Powder PS of about 75 μm in size (MP75) were co-cultured with a model freshwater fungus, namely Acremonium strictum strain KR21–2, for seven days to form biofilms on their surface. We also determined the changes in surface physicochemical properties of the biofilm-covered MPs (BMPs) and the heavy metal adsorption capacity of the original MPs and BMPs. The results revealed that the biofilms improve the adsorption of heavy metals on MPs, and the particle size of MPs plays a crucial role in biofilm colonization and adsorption of heavy metals by BMPs. MP75 can carry more biofilm on its surface than that of the two MP4000s and form heteroaggregates with biofilms. In addition, there were more functional groups on the surface of BMP75 than on the surface of the two BMP4000s, which could promote the electrostatic interaction and chemical association of heavy metals. Moreover, BMP75 exhibited a higher capacity to adsorb Cu and reduce Cr (VI), which may be related to the functional groups in its biofilm. Overall, this study showed that after biofilms colonization, BMPs of smaller size have more significant potential as a metal vector, and the particle size deserves more scientific attention during the risk assessment.
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•Microplastics with small particle size was easier colonized by biofilms.•Biofilms altered the surface characteristics of microplastics.•Biofilms significantly enhanced the adsorption of metals onto microplastics.•The biofilm-covered microplastics affect the oxidation state of chromium.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Ultrathin membranes with potentially high permeability are urgently demanded in water purification. However, their facile, controllable fabrication remains a grand challenge. Herein, we demonstrate a ...metal-coordinated approach towards defect-free and robust membranes with sub-10 nm thickness. Phytic acid, a natural strong electron donor, is assembled with metal ion-based electron acceptors to fabricate metal-organophosphate membranes (MOPMs) in aqueous solution. Metal ions with higher binding energy or ionization potential such as Fe
and Zr
can generate defect-free structure while MOPM-Fe
with superhydrophilicity is preferred. The membrane thickness is minimized to 8 nm by varying the ligand concentration and the pore structure of MOPM-Fe
is regulated by varying the Fe
content. The membrane with optimized MOPM-Fe
composition exhibits prominent water permeance (109.8 L m
h
bar
) with dye rejections above 95% and superior stability. This strong-coordination assembly may enlighten the development of ultrathin high-performance membranes.
Targeting the epidermal growth factor receptor (EGFR) either alone or in combination with chemotherapy is effective for patients with RAS wild type metastatic colorectal cancer (mCRC). However, only ...a small percentage of mCRC patients are sensitive to anti-EGFR therapy and even the best cases finally become refractory to this therapy. It has become apparent that the RAS mutations correlate with resistance to anti-EGFR therapy. However, these resistance mechanisms only account for nearly 35% to 50% of nonresponsive patients, suggesting that there might be additional mechanisms. In fact, several novel pathways leading to escape from anti-EGFR therapy have been reported in recent years. In this review, we provide an overview of known and novel mechanisms that contribute to both primary and acquired anti-EGFR therapy resistance, and enlist possible treatment strategies to overcome or reverse this resistance.
This study was performed to reveal mitochondria changes and metabolome differences between bovine longissimus lumborum (LL) and psoas major (PM) muscles within the first 24 h postmortem. PM showed ...significant lower (P < .05) pH than LL at 6 h and 12 h postmortem. LL had significant higher (P < .05) mitochondrial membrane potential and lower mitochondrial reactive oxygen species levels than PM at 24 h postmortem. For metabolome, distinctive separation between LL and PM could be seen from principal component analysis and hierarchical clustering analysis. Carnosine, L-histidine and adenosine diphosphate were found with higher abundances in LL. Whereas higher abundances of inosine and hypoxanthine were detected in PM, which indicated distinct purine metabolism rate between muscle types. Higher abundances of glycerophospholipids in PM may increase risk of oxidation damage, and subsequently result in inferior meat quality during extended retail display. The results of this study provided an idea for further research regarding the muscle-specific mitochondrial ROS on meat quality.
•Metabolome profiles of bovine LL and PM in early postmortem were analyzed.•LL had higher MMP and lower ROS level than that of PM at 24 h postmortem.•A total of 13 glycerophospholipids were overabundant in PM.•Higher abundance of ADP was found in LL, whereas inosine and hypoxanthine in PM.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Targeted metabolomics was applied to elucidate energy metabolites in bovine (Chinese Jinjiang yellow cattle, n = 4) longissimuss lumborum (LL) and psoas major (PM) muscles during the early postmortem ...period (1 h, 6 h, 12 h, and 24 h). The a* value increased significantly (P < .05) in both of LL and PM within 24 h postmortem. Compared with PM, LL had higher area percentage of type IIB fibers (48.41% vs 30.60%, P < .001) and lower proportion of type I fibers (24.98% vs 46.16%, P < .001). A total of 22 energy metabolites were successfully detected by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The principal component and hierarchical cluster analyses of these metabolites exhibited clear distinctions between LL and PM samples from different postmortem periods. Enzymic activities (lactate dehydrogenase, malate dehydrogenase, and succinate dehydrogenase), contents of pyruvate and numbers of metabolites involved in tricarboxylic acid (TCA) cycle evidenced different changes in LL and PM, which indicated distinguished metabolic patterns between them.
•Targeted metabolites of bovine LL and PM in the early postmortem were analyzed.•LL and PM showed significant difference in the composition of muscle fiber types.•PCA and HCA results suggested distinguished metabolic patterns between LL and PM.•Contents of metabolites involved in TCA cycle changed differently in LL and PM.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Organolead trihalide perovskites have attracted great attention due to the stunning advances in both photovoltaic and light-emitting devices. However, the photophysical properties, especially the ...recombination dynamics of photogenerated carriers, of this class of materials are controversial. Here we report that under an excitation level close to the working regime of solar cells, the recombination of photogenerated carriers in solution-processed methylammonium-lead-halide films is dominated by excitons weakly localized in band tail states. This scenario is evidenced by experiments of spectral-dependent luminescence decay, excitation density-dependent luminescence and frequency-dependent terahertz photoconductivity. The exciton localization effect is found to be general for several solution-processed hybrid perovskite films prepared by different methods. Our results provide insights into the charge transport and recombination mechanism in perovskite films and help to unravel their potential for high-performance optoelectronic devices.
Reactive oxygen species (ROS) are recognized as important regulators of cell division and differentiation. The Arabidopsis thaliana P-loop NTPase encoded by APP1 affects root stem cell niche identity ...through its control of local ROS homeostasis. The disruption of APP1 is accompanied by a reduction in ROS level, a rise in the rate of cell division in the quiescent center (QC) and the promotion of root distal stem cell (DSC) differentiation. Both the higher level of ROS induced in the app1 mutant by exposure to methyl viologen (MV), and treatment with hydrogen peroxide (H2O2) rescued the mutant phenotype, implying that both the increased rate of cell division in the QC and the enhancement in root DSC differentiation can be attributed to a low level of ROS. APP1 is expressed in the root apical meristem cell mitochondria, and its product is associated with ATP hydrolase activity. The key transcription factors, which are defining root distal stem niche, such as SCARECROW (SCR) and SHORT ROOT (SHR) are both significantly down-regulated at both the transcriptional and protein level in the app1 mutant, indicating that SHR and SCR are important downstream targets of APP1-regulated ROS signaling to control the identity of root QC and DSCs.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Biogenic birnessite was used to synthesize microtube-type Li+ ion sieve.•The biomineral facilitates LMO formation at a lower temperature.•HMO-MT with high Li+ uptake capacity was ...obtained.•Temperature effects on properties of HMO-MTs were studied.
Microbial transformations, a primary pathway for the Mn oxides formation in nature, provide potential for material-oriented researchers to fabricate new materials. Using Mn oxidizing fungus Paraconiothyrium sp. WL-2 as a bio-oxidizer as well as a bio-template, a special lithium ion sieve with microtube morphology was prepared through a solid-state transformation. Varying the calcination temperature from 300 to 700°C was found to influence sample properties and consequently, the adsorption of Li+. Lithium manganese oxide microtube (LMO-MTs) calcined at different temperatures as well as their delithiated products (HMO-MTs) were characterized by X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Calcination temperatures affect not only the content but also the crystal structure of LMO spinel, which is important in Li+ adsorption. The optimized sample was obtained after calcination at 500°C for 4h, which shows higher Li+ adsorption capacity than particulate materials.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Although the Cs adsorption onto soil minerals has been widely studied, the structural factor of Mn oxides affecting the adsorption behavior of trace amounts of Cs is unclear. In order to elucidate ...the adsorption mechanisms of radioactive Cs at trace levels and the role of Mn oxides on Cs migration in the terrestrial environment, the Cs adsorption onto birnessite and todorokite was investigated for a wide range of concentrations (1×10−10mol/L to 0.1mol/L) and an ion-exchange model was used to interpret the adsorption data. Although birnessite showed a higher Cs adsorption capacity than todorokite, most of the Cs adsorbed onto birnessite was desorbed by ion exchange. Two types of adsorption sites were observed for todorokite. Despite low density, the selectivity coefficient was much higher for the T1 site (LogNaCsKsel = 4.2) than for the T2 site (LogNaCsKsel=−0.6). Sequential extraction was carried out at Cs concentrations of 1×10−9mol/L and 1×10−3mol/L. At lower concentrations, approximately 34% of the adsorbed Cs was residual in the todorokite after the sequential extraction; this value was much higher than the results for the Cs-adsorbed birnessite as well as the Cs-adsorbed todorokite at higher concentrations. The present results indicate that the structural factors of Mn oxides significantly affect the retention capacity of radioactive Cs. Aside from phyllosilicate minerals, todorokite also contributes to the fixation of radioactive Cs in soils.
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•Structural factors of Mn oxides significantly affect Cs retention at trace level.•Most of the Cs adsorbed onto birnessite could be desorbed by ion exchange.•A fraction of Cs adsorbed onto todorokite was not desorbed by ion-exchange.•Two types of adsorption sites were observed for todorokite.•Todorokite may also contributes to the fixation of radioactive Cs in soils
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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