Magnetite Triggering Enhanced Direct Interspecies Electron Transfer: A Scavenger for the Blockage of Electron Transfer in Anaerobic Digestion of High-Solids Sewage Sludge

At present, high-solids anaerobic digestion of sewage sludge has drawn great attention due to the superiority of its small land area footprint and low energy consumption. However, a high organic loading rate may cause acids accumulation and ammonia inhibition, thus leading to an inhibited pseudo-steady state in which electron transfer through interspecies hydrogen transfer (IHT) between acetogens and methanogens is blocked. In this study, adding 50 mg/g TS (total solid) magnetite clearly reduced the accumulation of short-chain fatty acids and accelerated methane production by 26.6%. As demonstrated, the individual processes of anaerobic digestion could not be improved by magnetite when methanogenesis was interrupted. Analyzing stable carbon isotopes and investigating the methanogenesis pathways using acetate and H₂/CO₂ as substrates together proved that direct interspecies electron transfer (DIET) was enhanced by magnetite. Metatranscriptomic analysis and determination of key enzymes showed that IHT could be partially substituted by enhanced DIET, and acetate-dependent methanogenesis was improved after the blockage of electron transfer was scavenged. Additionally, the expression of both pili and c-type cytochromes was found to decrease, indicating that magnetite could replace their roles for efficient electron transfer between acetogens and methanogens; thus, a robust chain of electron transfer was established

Spatial Configuration of Extracellular Organic Substances Responsible for the Biogas Conversion of Sewage Sludge

The influence of the key structural features of sludge that are responsible for the low anaerobic conversion efficiency of sludge is poorly understood. In this study, sludge organic substances are reclassified into extracellular organic substances (EOSs) and cell biomass on the basis of sludge structure. The roles of EOSs in the biogas conversion of both sewage sludge (SS) and model sludge (MS) were investigated. It is observed that with increasing EOS content the net cumulative methane production (NCMP) of the sludge decreased by 36.4%, implying the crucial roles of EOSs in anaerobic sludge digestion. The experimental results showed that with increasing EOS content in sludge, the extracted EOS content decreased, indicating that the structural stability of EOSs in sludge was reinforced. Considering that the biodegradation of EOSs typically depends on structural stability, spatial configuration of EOSs has been hypothesized to account for the low anaerobic digestion efficiency. Further analyses of the spatial configuration of EOSs from the MS and SS revealed that the random-coil shape with extended chains in MS is more readily biodegradable than the dense globule shape with cross-linked chains in SS. These findings shed light on the underlying mechanism responsible for the low biogas conversion of sludge

Additional file 1 of Dynamics and concordance alterations of regional brain function indices in vestibular migraine: a resting-state fMRI study

Additional file 1: Supplementary Fig. 1. Brain regions with altered dynamics of ALFF in VM patients relative to healthy controls (applied window size: 30 TR). ALFF, amplitude of low-frequency fluctuations; VM, vestibular migraine; TR, time repetition. Supplementary Fig. 2. Brain regions with altered dynamics of ReHo in VM patients relative to healthy controls (applied window size: 30 TR). ReHo, regional homogeneity; VM, vestibular migraine; TR, time repetition. Supplementary Fig. 3. Correlation of vertigo disease duration with ALFF dynamics （Z score standardized）of the left MOG in the VM group (applied window size: 30 TR). ALFF, amplitude of low-frequency fluctuations; VM, vestibular migraine; MOG, middle occipital gyrus. Supplementary Fig. 4. Brain regions with altered voxel-wise temporal concordance between ALFF and ReHo in VM patients relative to healthy controls (applied window size: 30 TR). ALFF, amplitude of low-frequency fluctuations; ReHo, regional homogeneity; VM, vestibular migraine. Supplementary Fig. 5. Comparison of volume-wise concordance indices between the VM and HC groups (applied window size: 30 TR). (A) Time series of volume-wise concordance between ALFF and ReHo for typical subjects in the VM group and HC group. (B) Group comparison of the mean of volume-wise concordance between ALFF and ReHo. (C) Group comparison of the SD of volume-wise concordance between ALFF and ReHo. VM, vestibular migraine; HC, healthy controls; ALFF, amplitude of low-frequency fluctuations; ReHo, regional homogeneity; SD, Standard deviation. *P < 0.05; ns, not significant

Location of the archaeological sites studied within their chrono-cultural context.

<p>Location of the archaeological sites studied within their chrono-cultural context.</p

Dental shape relationships among modern and archaeological samples.

<p>Phenogram showing the M₂ shape relationships between the geographic and chronological mean shape of modern and archaeological samples.</p

Relationship between ¹³C and ¹⁵N isotopic values and the M₃ length measurements across XWG phases.

<p>Chronological phases of XWG are depicted by six different symbols. The Longshan specimens of phase 3 are clustered according to their M₃ length, either below or above the 37 mm threshold.</p

Details of modern and archaeological specimens for GMM analysis.

<p>IZCAS: Institute of Zoology Chinese Academy of Sciences (Beijing, China); IVPP: Institute of Vertebrate Paleontology and Paleoanthropology (Beijing, China).</p

Notched boxplot of the M₂ Log transformed centroid size for all samples.

<p>The box represents 50% of the variation around the median (horizontal black line); the brackets represent the minimum and maximum. Notches represent a 95% interval confidence of the median.</p

Molar shape differences between the two extent wild boar sub-species and the domestic pigs of China.

<p>First canonical variates (CV) computed on size corrected shape variables. The molar shape divergence between the wild and domestic type along the CV1 is displayed by shape reconstruction on each axes extremity; the divergence between the two wild boar sub-species is displayed along the CV2. Confidence ellipses contain 90% of the data points with a 0.9 probability.</p

Scatter plot of the δ¹³C and δ¹⁵N values of bone collagen from the XWG site displayed per phase.

<p>Scatter plot of the δ¹³C and δ¹⁵N values of bone collagen from the XWG site displayed per phase.</p