Yellow
mealworms (larvae of Tenebrio molitor, Coleoptera: Tenebrionidae) have been proven to be capable of biodegrading
polystyrene (PS) products. Using four geographic sources, we found
that dark mealworms (larvae of Tenebrio obscurus) ate PS as well. We subsequently tested T. obscurus from Shandong, China for PS degradation capability. Our results
demonstrated the ability for PS degradation within the gut of T. obscurus at greater rates than T. molitor. With expanded PS foam as the sole diet,
the specific PS consumption rates for T. obscurus and T. molitor at similar sizes (2.0
cm, 62–64 mg per larva) were 32.44 ± 0.51 and 24.30 ±
1.34 mg 100 larvae–1 d–1, respectively.
After 31 days, the molecular weight (M
n) of residual PS in frass (excrement) of T. obscurus decreased by 26.03%, remarkably higher than that of T. molitor (11.67%). Fourier transform infrared spectroscopy
(FTIR) indicated formation of functional groups of intermediates and
chemical modification. Thermo gravimetric analysis (TGA) suggested
that T. obscurus larvae degraded PS
effectively based on the proportion of PS residue. Co-fed corn flour
to T. obscurus and wheat bran to T. molitor increased total PS consumption by 11.6%
and 15.2%, respectively. Antibiotic gentamicin almost completely inhibited
PS depolymerization. High-throughput sequencing revealed significant
shifts in the gut microbial community in both Tenebrio species that were associated with the PS diet and PS biodegradation,
with changes in three predominant families (Enterobacteriaceae, Spiroplasmataceae,
and Enterococcaceae). The results indicate that PS biodegradability
may be ubiquitous within the Tenebrio genus which could provide a bioresource for plastic waste biodegradation.
Highlights
The eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method.
Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel.
Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition.
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Abstract
Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.
Taking serious microwave pollution issues and the complex application environment into consideration, it is quite urgent to integrate several functions into one material. Electromagnetic (EM) absorbing materials with multiple functions are highly attractive to next-generation wireless techniques and portable electronic devices. Herein, melamine foam provides a decent platform for the uniform growth of Co-based metal− organic frameworks (MOFs), which bring the as-obtained hybrid foam with threedimensional porous network structure and combination of dielectric along with magnetic attenuation abilities as advanced materials in multifunctional fields. Remarkably, the relevant microwave absorption (MA) performance of the hybrid foam can reach an extremely high reflection loss value of −59.82 dB. Furthermore, the hybrid foam exhibits excellent infrared stealth and optimiztic heat insulation function, demonstrating the potential in plenty of practical applications. These results may arouse interests and inspirations of the elaborately design and facilely synthesis of highperformance foamlike microwave absorbers with multiple functions.
Genome-wide association studies (GWASs) have reproducibly associated variants within intergenic regions of 1p36.12 locus with osteoporosis, but the functional roles underlying these noncoding variants are unknown. Through an integrative functional genomic and epigenomic analyses, we prioritized rs6426749 as a potential causal SNP for osteoporosis at 1p36.12. Dual-luciferase assay and CRISPR/Cas9 experiments demonstrate that rs6426749 acts as a distal allele-specific enhancer regulating expression of a lncRNA (LINC00339) (∼360 kb) via long-range chromatin loop formation and that this loop is mediated by CTCF occupied near rs6426749 and LINC00339 promoter region. Specifically, rs6426749-G allele can bind transcription factor TFAP2A, which efficiently elevates the enhancer activity and increases LINC00339 expression. Downregulation of LINC00339 significantly increases the expression of CDC42 in osteoblast cells, which is a pivotal regulator involved in bone metabolism. Our study provides mechanistic insight into how a noncoding SNP affects osteoporosis by long-range interaction, a finding that could indicate promising therapeutic targets for osteoporosis.
The widely used β-lactam antibiotics such as penicillins and cephalosporins are known to be susceptible to Cu-catalyzed hydrolysis at their four-membered β-lactam ring. However, this study elucidates that Cu can in fact play multiple roles in promoting the hydrolysis and/or oxidation of β-lactam antibiotics under environmental aquatic conditions (pH 5.0-9.0 and 22 °C), depending on β-lactams' structural characteristics and solution pH. Most significantly, the β-lactam antibiotics that contain a phenylglycine primary amine group on the side chain can undergo direct oxidation by Cu via this functional group. On the other hand, the β-lactam ring of penicillins is susceptible to Cu-catalyzed hydrolysis, followed by oxidation of the hydrolysis product by Cu. In contrast, the β-lactam ring of cephalosporins is susceptible to Cu-catalyzed hydrolysis only. Solution pH influences the Cu-promoted transformation by affecting the β-lactam and Cu complexation through protonation/deprotonation of critical organic functional groups. When Cu acts as an oxidant to promote the transformation of β-lactam antibiotics to yield Cu, the overall role of Cu appears catalytic if the reaction occurs under ambient atmospheric condition, due to quick oxidation of Cu by oxygen to regenerate Cu. Compared to earlier literature that largely assumed only the hydrolytic catalyst role of Cu in promoting degradation of β-lactam antibiotics, the oxidative roles of Cu identified by this study mark important contributions to a more accurate mechanistic understanding.
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