Summary
Methane is an important greenhouse gas and acetate is the most important intermediate (average 70%) of the carbon flow to CH4 in paddy fields. Sulfate (e.g., gypsum) application can reduce ...CH4 emissions up to 70%. However, the effect of gypsum application on acetate degradation and the microbial communities involved are unclear. Therefore, we studied acetate‐dependent sulfate reduction in anoxic microcosms of Italian rice paddy soil, combining profiling of 16S rRNA and dissimilatory sulfite reductase (dsrB) genes and transcripts and rRNA based stable isotope probing (SIP) analysis. Methane production was completely inhibited by gypsum in the absence of exogenous acetate. Amended acetate (either 13C labelled or non‐labelled) was stoichiometrically coupled to sulfate reduction or CH4 production. With methyl fluoride in the presence of sulfate, added propionate and butyrate were incompletely oxidized to acetate, which transiently accumulated. After the depletion of propionate and butyrate the accumulated acetate was rapidly consumed. The relative abundance of dsrB and 16S rRNA genes and transcripts from Syntrophobacteraceae (Desulfovirga spp., Syntrophobacter spp. and unclassified Syntrophobacteraceae) increased upon addition of gypsum and acetate. Simultaneously, Syntrophobacteraceae affiliated species were significantly labelled with 13C. In addition, minor groups like Desulforhabdus spp., Desulfobacca spp. and Desulfotomaculum spp. substantially incorporated 13C into their nucleic acids. The relative abundance of Desulfovibrio spp. slightly increased upon gypsum amendments. However, 13C labelling of Desulfovibrio spp. was only moderate. In summary, Syntrophobacteraceae affiliated species were identified as the major acetotrophic sulfate reducers (SRB) in Italian paddy soil. The identification of these SRB as dominant acetate degraders well explained the scenarios of competition between SRB and acetoclastic methanogens as observed in rice paddy soil.
Microbial and viral communities transform the chemistry of Earth's ecosystems, yet the specific reactions catalyzed by these biological engines are hard to decode due to the absence of a scalable, ...metabolically resolved, annotation software. Here, we present DRAM (Distilled and Refined Annotation of Metabolism), a framework to translate the deluge of microbiome-based genomic information into a catalog of microbial traits. To demonstrate the applicability of DRAM across metabolically diverse genomes, we evaluated DRAM performance on a defined, in silico soil community and previously published human gut metagenomes. We show that DRAM accurately assigned microbial contributions to geochemical cycles and automated the partitioning of gut microbial carbohydrate metabolism at substrate levels. DRAM-v, the viral mode of DRAM, established rules to identify virally-encoded auxiliary metabolic genes (AMGs), resulting in the metabolic categorization of thousands of putative AMGs from soils and guts. Together DRAM and DRAM-v provide critical metabolic profiling capabilities that decipher mechanisms underpinning microbiome function.
Further minimizing the defect state density in the semiconducting absorber is vital to boost the power conversion efficiency of solar cells approaching Shockley-Queisser limit. However, it lacks a ...general strategy to control the precursor chemistry for defects density reduction in the family of iodine based perovskite. Here the alkaline environment in precursor solution is carefully investigated as an effective parameter to suppress the incident iodine and affects the crystallization kinetics during film fabrication, via rationale adjustment of the alkalinity of additives. Especially, a 'residual free' weak alkaline is proposed not only to shrink the bandgap of the absorber by modulating the stoichiometry of organic cation, but also to improve the open circuit voltage in the resultant device. Consequently, the certified efficiency of 20.87% (Newport) is achieved with one of the smallest voltage deficits of 413 mV in the planar heterojunction perovskite solar cell.
Oxidized corn starch (OS) has a good film-forming ability; however, its poor mechanical properties and moisture barrier are shortcomings. To improve the deficiencies of OS film, soy protein isolate ...(SPI) with different ratios (10%, 20%, and 30%) was incorporated into OS film at different pH values (6, 8, and 10) to investigate the mechanical and hydrophobic properties of the blended films. The blended films were characterized by water sensitivity, contact angle, mechanical properties, optical properties, and microstructure. The increases in the SPI ratio and pH reduced the moisture content and total soluble matter of the blended films. The reduction in water vapor permeability and the increase in contact angle from 37.3° to 104.5° suggested that the moisture barrier of the OS film was improved by SPI. The elongation at break of blended films increased, but the tensile strength decreased with increasing of SPI content and pH. The blended films prepared at pH 10 were more yellow and had higher transmittance. Scanning electron microscopy and atomic force microscopy showed that the blended films exhibited denser microstructures and smoother surfaces with the increasing pH. X-ray diffraction and thermogravimetric analysis implied that SPI interfered with the intermolecular interaction of OS.
Display omitted
•SPI reduced the tensile strength of the OS/SPI films, which was contrary to E.•The OS/SPI films had better water resistance than OS film.•The OS/SPI films presented a yellowish color and higher transmittance.•The physicochemical properties and microstructure of OS/SPI films are related to pH.
Air pollution may increase risk of Alzheimer's disease and related dementias (ADRD) in the U.S., but the extent of this relationship is unclear. Here, we constructed two national U.S. ...population-based cohorts of those aged ≥65 from the Medicare Chronic Conditions Warehouse (2000-2018), combined with high-resolution air pollution datasets, to investigate the association of long-term exposure to ambient fine particulate matter (PM
), nitrogen dioxide (NO
), and ozone (O
) with dementia and AD incidence, respectively. We identified ~2.0 million incident dementia cases (N = 12,233,371; dementia cohort) and ~0.8 million incident AD cases (N = 12,456,447; AD cohort). Per interquartile range (IQR) increase in the 5-year average PM
(3.2 µg/m
), NO
(11.6 ppb), and warm-season O
(5.3 ppb) over the past 5 years prior to diagnosis, the hazard ratios (HRs) were 1.060 (95% confidence interval CI: 1.054, 1.066), 1.019 (95% CI: 1.012, 1.026), and 0.990 (95% CI: 0.987, 0.993) for incident dementias, and 1.078 (95% CI: 1.070, 1.086), 1.031 (95% CI: 1.023, 1.039), and 0.982 (95%CI: 0.977, 0.986) for incident AD, respectively, for the three pollutants. For both outcomes, concentration-response relationships for PM
and NO
were approximately linear. Our study suggests that exposures to PM
and NO
are associated with incidence of dementia and AD.
Microbial syntrophy is a thermodynamically-based cooperation between microbial partners that share the small amounts of free energy for anaerobic growth. To gain insights into the mechanism by which ...syntrophic microorganisms coordinate their metabolism, we constructed cocultures of propionate-oxidizing
and hydrogenotrophic
and compared them to monocultures. Transcriptome analysis was performed on these cultures using strand-specific mRNA sequencing (RNA-Seq). The results showed that in coculture both
and
significantly upregulated the expression of genes involved in catabolism but downregulated those for anabolic biosynthesis. Specifically, genes coding for the methylmalonyl-CoA pathway in
and key genes for methanogenesis in
were substantially upregulated in coculture compared to monoculture. The putative flavin-based electron bifurcation/confurcation systems in both organisms were also upregulated in coculture. Formate dehydrogenase encoding genes in both organisms were markedly upregulated, indicating that formate was produced and utilized by
and
, respectively. The inhibition of syntrophic activity by formate and 2-bromoethanesulphonate (2-BES) but not H
/CO
also suggested that formate production was used by
for the recycling of intracellular redox mediators. Finally, flagellum-induced signal transduction and amino acids exchange was upregulated for syntrophic interactions. Together, our study suggests that syntrophic organisms employ multiple strategies including global metabolic shift, utilization of electron bifurcation/confurcation and employing formate as an alternate electron carrier to optimize their metabolisms for syntrophic growth.
Thermally conductive polymer composites with satisfactory mechanical performances are highly required for practical thermal management applications as thermal interface materials. Herein, ...all-graphitized graphene aerogels with highly aligned graphene network are fabricated with graphene oxide hydrogels as the precursor by directional-freezing followed by freeze-drying and subsequent graphitization at 2800 °C, which exhibit excellent thermal and electrical conductions and superelasticity. Thanks to the vertically aligned conductance network composed by the graphitized graphene sheets, an epoxy composite with only 0.75 vol% of the high-quality graphene exhibits an excellent vertical thermal conductivity of 6.57 W/(mK), which is among the highest through-plane thermal conductivities of polymer composites at similar loading of carbon nanofillers, and more than 37 times higher than that of neat epoxy matrix. The thermally and electrically conductive composite also exhibits greatly improved storage modulus, compressive strength and compressive strain at break.
Display omitted
Multi-walled carbon nanotube (MWCNT)/high density polyethylene (HDPE) and graphene nanosheets (GNS)/HDPE composites with a segregated network structure were prepared by alcohol-assisted dispersion ...and hot-pressing. Instead of uniform dispersion in polymer matrix, MWCNTs and GNSs distributed along specific paths and formed a segregated conductive network, which results in a low electrical percolation threshold of the composites. The electrical properties of the GNS/HDPE and MWCNT/HDPE composites were comparatively studied, it was found that the percolation threshold of the GNS/HDPE composites (1
vol.%) was much higher than that of the MWCNT/HDPE composites (0.15
vol.%), and the MWCNT/HDPE composite shows higher electrical conductivity than GNS/HDPE composite at the same filler content. According to the values of critical exponent,
t, the two composites may have different electrical conduction mechanisms: MWCNT/HDPE composite represents a three-dimensional conductive system, while the GNS/HDPE composite represents a two-dimensional conductive system. The improving effect of GNSs as conducting fillers on the electrical conductivity of their composites is far lower than theoretically expected.
Floating Offshore Wind has the potential to provide an effective solution for the increasing energy demand of coastal communities around the world if the specific risks associated with this novel ...technology are understood and evaluated. In this paper an enhanced risk matrix methodology was developed for the risk assessment of a generic FOWT through the introduction of a third risk parameter namely the ‘technology category’. The final risk score is calculated using the average value of all contributing parameters: consequence, likelihood and ‘technology category’ for the avoidance of identical risk values. Individual data collection will eliminate the biases associated with the conventional risk assessment process. The critical failure causes/hazards and failure modes, ranked based on the obtained risk scores, indicate the Floater Unit as the most hazardous of the supporting sub-structures with corrosion as its dominant failure cause. The proposed methodology validation is ascertained through the comparison of obtained results with two similar studies. Its flexibility of use and implementation, combined with its familiar background, facilitate the application of the proposed method for a technological risk assessment of any young sector.
•The qualitative risk assessment dominates offshore industries.•Technology category is a key risk parameter for novel technologies.•Technology category impacted differently each considered sub-structure.•The granularity achieved for risk scores avoids the occurrence of same risk value.•Floater Unit identified as the most hazardous sub-structure with corrosion as dominant cause.
SUMMARY
Lacustrine and marine sediments are one of the main sources of information in constructing Holocene global geomagnetic field models. The use of sediment records, however, leads to the ...question whether the compaction of sediments leads to a systematic biasing of inclination. We evaluate 78 sedimentary records worldwide for inclination flattening using the Elongation–Inclination (E/I) method; 20 records indicate flattening. The uncorrected and corrected values for inclination are compared to global geomagnetic field models. The results suggest that the uncorrected values agree better with the predictions from global geomagnetic field models based on sediment and archaeomagnetic data, but also with a model independent of sediment data. The 20 sites are located in mid-latitudes where inclination anomalies are predicted both in the Holocene and throughout the Brunhes epoch. Our results demonstrate that shallow inclination may not only result from compaction but may reflect the structure of the geomagnetic field on short timescales. This suggests that secular variation is not averaged out over a time period that covers the Holocene.
PDF
