Optimizing adsorption performance of sludge-derived biochar via inherent moisture-regulated physicochemical properties.

Understanding the impact of abundant inherent moisture in sewage sludge on the physicochemical properties and adsorption applications of sludge-derived biochar (SDB) contributed significantly to promoting economical sludge reuse. The moisture (0-80%) contributed to the development of micropore and mesopore in SDB at 400 °C, resulting in a maximum increase in specific surface area (SSA) and total pore volume (TPV) of SDB by 38.47% (84.811-117.437 m2/g) and 92.60% (0.0905-0.1743 m3/g), respectively. At 600/800 °C, moisture only facilitated mesopore formation, while was exacerbated with increasing moisture content. Despite reduction in SSA during this stage, TPV increased by a maximum of 20.47% (0.1700-0.2048 m3/g). The presence of moisture during pyrolysis led to an increase in the formation of 3-5 thickened benzene rings and defective structures in SDB, along with more C=O, O-C=O/-OH, pyrrole N, pyridine N, and thiophene. As a result, moisture (40%/80%) increased the maximum adsorption capacity (76.2694-88.0448/90.1190 mg/g) of SDB (600 °C) for tetracycline, mainly due to enhanced pore filling effect and hydrogen bonding induced by improved physicochemical properties. This study offered a novel approach for optimizing the performance of SDB adsorption applications by manipulating the sludge moisture, which is critical for practical sludge management.

Roles of catalytic ozonation by bimetallic Fe/Ce loading sludge-derived biochar in amelioration of sludge dewaterability: Performance and implementation mechanisms.

In this study, an environmentally friendly alternative was developed using catalytic ozonation by sludge-derived biochar loaded with bimetallic Fe/Ce (O3/SBC-FeCe) for enhanced sludge dewatering. The results indicated that the lowest capillary suction time (CST) of 20.9 s and water content of dewatered sludge cake (Wc) of 64.09% were achieved under the dosage of 40 mg O3/g dry solids (DS) and 0.4 g SBC-FeCe/g DS which were considered as the optimum condition. In view of excellent electron exchanging capacity of SBC-FeCe with rich Lewis acid sites and conversions of valence sates of Fe and Ce, more O3 were decomposed into reactive oxygen species under the catalytic action of SBC-FeCe, which strengthened oxidizing capacity. Enhanced oxidation rendered sludge cells inactivation and compact network structure rupture releasing intracellular water and organic substances. Subsequently, hydrophilic organic matters were attacked and eliminated lessening sludge viscosity and colloidal forces and intensifying hydrophobicity and flowability. In addition, changes of sludge morphology suggested that sludge roughness was alleviated, structural strength and compressibility were raised and porous and retiform structure was constructed providing channels for water outflow by adding skeleton builder of SBC-FeCe. Overall, the synergistic interaction of strengthened oxidation and skeleton construction improved sludge dewaterability.

Functional characterization and in vitro pharmacological rescue of KCNQ2 pore mutations associated with epileptic encephalopathy.

Mutations in the KCNQ2 gene encoding KV7.2 subunit that mediates neuronal M-current cause a severe form of developmental and epileptic encephalopathy (DEE). Electrophysiological evaluation of KCNQ2 mutations has been proved clinically useful in improving outcome prediction and choosing rational anti-seizure medications (ASMs). In this study we described the clinical characteristics, electrophysiological phenotypes and the in vitro response to KCNQ openers of five KCNQ2 pore mutations (V250A, N258Y, H260P, A265T and G290S) from seven patients diagnosed with KCNQ2-DEE. The KCNQ2 variants were transfected into Chinese hamster ovary (CHO) cells alone, in combination with KCNQ3 (1:1) or with wild-type KCNQ2 (KCNQ2-WT) and KCNQ3 in a ratio of 1:1:2, respectively. Their expression and electrophysiological function were assessed. When transfected alone or in combination with KCNQ3, none of these mutations affected the membrane expression of KCNQ2, but most failed to induce a potassium current except A265T, in which trace currents were observed when co-transfected with KCNQ3. When co-expressed with KCNQ2-WT and KCNQ3 (1:1:2), the currents at 0 mV of these mutations were decreased by 30%-70% compared to the KCNQ2/3 channel, which could be significantly rescued by applying KCNQ openers including the approved antiepileptic drug retigabine (RTG, 10 µM), as well as two candidates subjected to clinical trials, pynegabine (HN37, 1 µM) and XEN1101 (1 µM). These newly identified pathologic variants enrich the KCNQ2-DEE mutation hotspots in the pore-forming domain. This electrophysiological study provides a rational basis for personalized therapy with KCNQ openers in DEE patients carrying loss-of-function (LOF) mutations in KCNQ2.

GABRG2 Variants Associated with Febrile Seizures.

Febrile seizures (FS) are the most common form of epilepsy in children between six months and five years of age. FS is a self-limited type of fever-related seizure. However, complicated prolonged FS can lead to complex partial epilepsy. We found that among the GABAA receptor subunit (GABR) genes, most variants associated with FS are harbored in the γ2 subunit (GABRG2). Here, we characterized the effects of eight variants in the GABAA receptor γ2 subunit on receptor biogenesis and channel function. Two-thirds of the GABRG2 variants followed the expected autosomal dominant inheritance in FS and occurred as missense and nonsense variants. The remaining one-third appeared as de novo in the affected probands and occurred only as missense variants. The loss of GABAA receptor function and dominant negative effect on GABAA receptor biogenesis likely caused the FS phenotype. In general, variants in the GABRG2 result in a broad spectrum of phenotypic severity, ranging from asymptomatic, FS, genetic epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome individuals. The data presented here support the link between FS, epilepsy, and GABRG2 variants, shedding light on the relationship between the variant topological occurrence and disease severity.

The roads taken and not taken: Trends of anammox-based wastewater treatment in China.

•Grants supporting anammox for wastewater treatment in China was analyzed.•The next frontiers of anammox research are prospected.•Anammox-based biotechnologies potentially drives innovation in water sector.

The UBE2C/CDH1/DEPTOR axis is an oncogene and tumor suppressor cascade in lung cancer cells.

Ubiquitin-conjugating enzyme E2C (UBE2C) mediates ubiquitylation chain formation via the K11 linkage. While previous in vitro studies showed that UBE2C plays a growth-promoting role in cancer cell lines, the underlying mechanism remains elusive. Still unknown is whether and how UBE2C plays a promoting role in vivo. Here we report that UBE2C was indeed essential for growth and survival of lung cancer cells harboring Kras mutations, and UBE2C was required for KrasG12D-induced lung tumorigenesis, since Ube2c deletion significantly inhibited tumor formation and extended the lifespan of mice. Mechanistically, KrasG12D induced expression of UBE2C, which coupled with APC/CCDH1 E3 ligase to promote ubiquitylation and degradation of DEPTOR, leading to activation of mTORC signaling. Importantly, DEPTOR levels fluctuated during cell cycle progression in a manner dependent on UBE2C and CDH1, indicating their physiological connection. Finally, Deptor deletion fully rescued the tumor inhibitory effect of Ube2c deletion in the KrasG12D lung tumor model, indicating a causal role of Deptor. Taken together, our study shows that the UBE2C/CDH1/DEPTOR axis forms an oncogene and tumor suppressor cascade that regulates cell cycle progression and autophagy and validates UBE2C an attractive target for lung cancer associated with Kras mutations.

Sirolimus treatment for tuberous sclerosis complex prior to epilepsy: Evidence from a registry-based real-world study.

OBJECTIVE: To evaluate whether sirolimus treatment could relieve the later burden of new-onset seizures in patients with tuberous sclerosis complex (TSC) prior to epilepsy. METHODS: A real-world matched case-control study was nested in another registry cohort study. Infants with TSC (<12 months old) without seizures whose parents agreed on sirolimus treatment for other symptoms were eligible for inclusion to the early sirolimus (ES) group. These patients were enrolled from 2015 to 2018. Controls in the late sirolimus (LS) group were matched from the registry cohort database for 2015-2018. Age and genotype were used as the initial stratifying criteria and other symptoms as the greedy matching criteria at a matching ratio of 1:4. None of the preventive drugs were introduced before seizure onset or before 2 years of age in the LS group. Both groups were followed up until June 2020. The primary objective was a comparison of the characteristics of the first seizure between the two groups. The secondary objective was the assessment of the final seizure status at the endpoint. RESULTS: There were 42 and 168 patients with TSC in the ES and LS groups, respectively. Early sirolimus treatment significantly reduced the seizure onset, especially in the patients aged <6 months. The mean onset-age was significantly delayed by sirolimus treatment (11.34±7.93 months vs. 6.94±6.03 months, P<0.001). The subtype of seizures that benefited the most was spastic (onset) seizures (all were infantile spasms) [5/42 (11.90%) vs. 73/168 (43.45%), P<0.001]; these seizures were either eliminated or alleviated. The sirolimus treatment addition prior to seizures was more effective than its addition after seizures in reducing drug-resistant epilepsy [10/42 (23.81%) vs. 70/147 (47.62%), P=0.004]. CONCLUSION: Early sirolimus treatment for TSC effectively modified the disease by preventing infantile spasms, delaying seizure onset, and relieving its severity. The anti-epileptogenic effect of sirolimus may be time- and dose-dependent.

Efficacy of levetiracetam in STXBP1 encephalopathy with different phenotypic and genetic spectra.

OBJECTIVE: Syntaxin binding protein 1 (STXBP1) plays an important role in the release of synaptic vesicles. STXBP1-related encephalopathy is a brain dysfunction caused by STXBP1 variation. Levetiracetam (LEV) exerts antiepileptic effects by binding to synaptic vesicle protein 2A (SV2A). This study aimed to analyze the prognosis of LEV treatment of STXBP1 encephalopathy (STXBP1-E) and the correlation among genotype, phenotype, and LEV efficacy. METHODS: Patients with pathogenic STXBP1 variants were collected from multiple centers, and their clinical history, video electroencephalogram (vEEG) characteristics, imaging examination data, and anti-seizure medication (ASM) history were systematically analyzed. The ASMs related to the prognosis were explored. RESULTS: Forty patients with STXBP1-E were enrolled in this study. The detailed ASM usage of 37 patients was recorded without intervening in ASM selection. At the endpoint of six months treatment, the results of Fisher's exact test showed that in all ASMs, LEV affected the prognosis of patients with STXBP1-E. LEV was effective in improving the partial remission rate but did not achieve seizure freedom. However, LEV monotherapy could achieve seizure freedom in patients with other early-onset epileptic and encephalopathy. For refractory West syndrome (WS) or Ohtahara syndrome (OS), LEV combined with other ASMs could improve the seizure remission rate. CONCLUSION: LEV increased the seizure reduction rate and improved the vEEG characteristics in patients with STXBP1-E, but not seizure freedom. LEV combined with other ASMs could increase the seizure reduction rate, especially for refractory WS or OS. Thus, LEV could be considered after identifying the pathogenicity of STXBP1 variants.

Biomethane production from waste activated sludge promoted by sludge incineration bottom ash: The distinctive role of metal cations and inert fractions.

Sludge incineration bottom ash (SA), a solid waste generated by incineration of waste activated sludge (WAS), has been demonstrated as an inexpensive additive to increase biomethane production from anaerobic digestion (AD) of WAS. However, how SA improved methanogenic performance of a WAS digester remains elusive. Here, we addressed this question by fractionating the SA into accessible leachate (SA-L) and inert residue (SA-R) and investigating their individual effects. The cumulative biomethane production was increased by 6.7%, 20.2% and 39.6% with addition of SA-L, SA-R and SA, respectively. Mechanistic study showed that release of organic-binding metals (Ca and Fe) from SA dissolution suppressed volatile fatty acids production by increasing the apparent activation energy (AAE) and decreasing the surface binding sites for hydrolytic/acidogenic enzymes during WAS hydrolysis-acidogenesis, while trace elements in SA-L promoted metabolism of methanogens (Methanothermobacter and Methanosarcina). In contrast, the gypsum/silicate-cored SA-R facilitated hydrolysis-acidogenesis with reduced AAE but drastically inhibited methanogenesis due to competition of sulfate-reducing bacteria Thermodesulfovibrio. The comparative analysis of KEGG-based functional genes indicated that the enhanced methane metabolism and reductive CO2 fixation pathways with SA addition could result from the release of trace elements to support key enzyme activities.

Anaerobic ammonium oxidation (anammox) promoted by pyrogenic biochar: Deciphering the interaction with extracellular polymeric substances (EPS).

Efficient biological nitrogen removal (BNR) by anaerobic ammonium oxidation (anammox) can be achieved with presence of redox-active pyrogenic biochar that potentially acting as an insoluble electron acceptor. Anammox bacteria and other symbiotic consortia are surrounded by extracellular polymeric substances (EPS) forming aggregate architecture, which also contains electrochemical-active biomolecules such as aromatic proteins and humic substances. Therefore, understanding the role of EPS is necessary in biochar-promoting anammox process. Herein, we investigated the influence of biochar with granular-sized (GP) and micrometer-sized (MP) particle sizes on microbiology and characteristics of EPS in anammox sludge. Addition of GP and MP biochar not only improved the BNR efficiency by 17.5% and 34.6%, respectively, but also increased the relative abundance of Candidatus Brocadia. The bulk and bound EPS contents substantially decreased in biochar-amended groups, while more slime EPS was produced. Spectroscopic (FTIR, Raman, and circular dichroism) and electrochemical (voltammetry and impedance spectrum) analyses revealed that biochar addition enhanced the structural integrity and electron-transfer capability of anammox sludge. EPS depletion led to a steep decrease in BNR efficiency (21.5% vs 83.0% with EPS-retained sludge), whereas it resumed to 42.1% in the presence of MP biochar. Electron transport system activity data showed that biochar replenished the loss of anaerobic respiration metabolism due to EPS depletion. In summary, these results suggested that EPS possibly work as transient mediator for shuttling electrons from ammonium oxidation to soluble (nitrite) and insoluble electron acceptors (redox-active biochar).

Influence of sludge organic matter on elimination of polycyclic aromatic hydrocarbons (PAHs) from waste activated sludge by ozonation: Controversy over aromatic compounds.

Ozonation has been widely used as a viable advanced oxidation process (AOP) for elimination of PAHs in waste activated sludge through effective sludge disintegration and abatement of organic pollutants. However, sludge organic matter (SOM) influences PAHs degradation during ozone treatment is still rarely understood. In this study, we investigated such an influence with the aid of solid-state 13C nuclear magnetic resonance (NMR) spectroscopy and the corresponding two-dimensional correlation analysis (2D-COS) strategy. The results showed that the degradation of SOM macromolecules in the order of aromatic substances > aliphatic carbon > α carbon > amides groups > O-alkyl upon ozone treatment. Moreover, the PAHs removal efficiency was positively correlated with the aromaticity of sludge (R2 = 0.84-0.98), while negative associated with its aliphaticity (R2 = 0.81-0.95). Lastly, humic acid (HA) was used as a proxy of aromatic SOM to further explore their interaction with PAHs in sludge matrix. The results revealed that freely dissolved (HA-D) and suspended particulates (HA-S) imposed distinctively different influence on ozone-based PAHs degradation. The HA-S facilitated the elimination of PAHs by 7.95 ± 0.11%, while those HA-D reduced the removal efficiency by 16.70 ± 0.13%.

Critical Review of Advances in Engineering Nanomaterial Adsorbents for Metal Removal and Recovery from Water: Mechanism Identification and Engineering Design.

Nanomaterial adsorbents (NAs) have shown promise to efficiently remove toxic metals from water, yet their practical use remains challenging. Limited understanding of adsorption mechanisms and scaling up evaluation are the two main obstacles. To fully realize the practical use of NAs for metal removal, we review the advanced tools and chemical principles to identify mechanisms, highlight the importance of adsorption capacity and kinetics on engineering design, and propose a systematic engineering scenario for full-scale NA implementation. Specifically, we provide in-depth insight for using density functional theory (DFT) and/or X-ray absorption fine structure (XAFS) to elucidate adsorption mechanisms in terms of active site verification and molecular interaction configuration. Furthermore, we discuss engineering issues for designing, scaling, and operating NA systems, including adsorption modeling, reactor selection, and NA regeneration, recovery, and disposal. This review also prioritizes research needs for (i) determining NA microstructure properties using DFT, XAFS, and machine learning and (ii) recovering NAs from treated water. Our critical review is expected to guide and advance the development of highly efficient NAs for engineering applications.

The extent of sludge solubilization allows to estimate the efficacy of ozonation for removal of polycyclic aromatic hydrocarbons (PAHs) in municipal sewage sludge.

Ozone treatment has been proven as an effective technology for removing PAHs in municipal sewage sludge. However, given the complex interaction of PAHs with sludge extracellular polymeric substances (EPS), effective sludge disintegration is required to make PAHs more accessible to oxidants, which also affects PAHs partitioning. Here, we investigated two treatment systems, namely ozonation (ozone) and sequential hydrodynamic cavitation and ozonation (HC+ozone), under varied conditions, to determine whether the extent of sludge disintegration can estimate a measurable removal of PAHs. The results showed that both the PAHs removal efficiency and kinetics highly depended on pH and ozone dose. Although no significant removal of PAHs occurred during HC treatment, the observed rate constants for Σ16 PAHs removal in HC+ozone system were 1.2-1.4-fold higher than those obtained in ozone system under the same condition. The accelerated PAHs removal could be attributed to the reduced flocs size (80% smaller) and increased soluble EPS concentration (5-fold higher) with HC pretreatment. Lastly, a positive correlation was noted between the PAHs removal efficiency and soluble EPS concentration (R2 = 0.85), indicating the important role of dissolved and colloidal matter (DCM) for PAHs partitioning between aqueous and particulate phases.

Alleviating the nitrite stress on anaerobic ammonium oxidation by pyrolytic biochar.

The nitrite (NO2-) inhibition in anaerobic ammonium oxidation (anammox) process is widely reported. Here, the effects of three pyrolytic biochars (CS300, CS550 and CS800) were investigated to alleviate NO2- stress on anammox process under exposure of varied NO2--N concentrations (70, 200, 400 and 600 mg L-1). No nitrite inhibition was observed at 70 mg N L-1. However, the total nitrogen removal efficiency (TNREs) decreased with NO2--N concentration increased, while the biochar-amended groups achieved higher TNREs than the control (CK). At 200 mg N L-1, the TNREs were 60.2%, 99.0%, 98.5% and 86.6% for CK, CS300, CS550 and CS800, respectively. At 400 mg N L-1, the TNREs were 23.3%, 56.0%, 37.1% and 29.7% for CK, CS300, CS550 and CS800, respectively. At 600 mg N L-1 in which severe inhibition was observed, the TNREs were increased by 231% (p = 0.002), 149% (p = 0.014), and 51.0% (p = 0.166) for CS300, CS550 and CS800, respectively, as compared to CK, with the corresponding specific anammox activity increased by 3.1-, 2,0- and 1.1-folds, respectively. CS300 enriched the relative abundance of Candidatus Kuenenia and increased the gene copies of functional genes (hzsA, hdh, nirS and nirK). Besides, CS300 effectively alleviated the suppression of three membrane-associated enzyme complexes for anammox electron transport chain, indicating the possible contribution of redox-active moieties of CS300 to energy conversion metabolism for mitigating the NO2--N inhibition. This study provided an effective strategy for alleviating NO2--N stress by applying an environmentally compatible material (biochar) on anammox process.

Towards efficient elimination of polycyclic aromatic hydrocarbons (PAHs) from waste activated sludge by ozonation.

Sewage sludge is one of the sinks for PAHs accumulation and concerns are growing regarding the environmental risk of the discharge of PAHs in waste activated sludge (WAS) as a major byproduct of sewage treatment. Here, we evaluated the effectiveness of ozone treatment to eliminate the 16 priority PAHs in WAS. The PAHs removal efficiency increased with ozone dosage and was strongly pH dependent. Even at ozone dosage of 40 mg O3·g-1, the PAHs removal efficiency at pH 9.0 (44.5%) was significantly higher than that observed at pH 5.0 and 200 mg O3·g-1 (41.7%). The pH-dependent elimination behavior of PAHs was attributed to the varying yield of hydroxyl radicals (OH) and degree of sludge disintegration (R2 = 0.88-0.92). Over 96% of the PAHs were in the particulate flocs (PF) phase, while the fraction bound to the freely dissolved (FS) and dissolved and colloidal (DC) matters was negligible, indicating the need of WAS disintegration during ozonation to make PAHs more accessible to O3 molecules and OH to initiate oxidation reactions. Failure of the three-compartment model to describe the PAHs sorption behavior in sludge matrix during ozonation implied that oxidation reaction occurred simultaneously with the partitioning of PAHs from PS to DC/FS fraction. Lastly, the results of the intermittent ozonation experiment demonstrated the interference of soluble organic compounds during PAHs degradation, particularly proteins and humic substances, as O3 and OH scavengers. At ozone dosage of 120 mg O3·g-1 (pH 9.0), the PAHs removal efficiency was improved by 19.5% by intermittent ozonation, as compared to continuous ozonation under the same conditions.

A sodium dichloroisocyanurate-based conditioning process for the improvement of sludge dewaterability and mechanism studies.

Sludge dewatering is necessary to reduce the volume of sludge for cost-effective transport and ultimate disposal. In this study, a novel combined chemical conditioning process was proposed to improve sludge dewatering performance in which sludge flocs were destructed by sodium dichloroisocyanurate (DCCNa) and re-flocculated by Al2(SO4)3 and the mechanism was elucidated. The results showed that sludge capillary suction time (CST) dropped to 15.4 s and moisture content of dewatered sludge cake (Mc) deceased to 71.01% respectively, after the application of combined conditioning with the optimal dosage of 200 mg DCCNa/g dry solids (DS) and 80 mg Al2(SO4)3/g DS. With chemical conditioning, sludge physicochemical properties were greatly changed. With the DCCNa application, the percentage of low-molecular-weight substances in soluble extracellular polymeric substances (S-EPS) increased. Also, the sludge zeta potential dropped from -16.85 mV to -25.45 mV and the median particle size (D50) decreased from 54.1 µm to 51.6 µm. However, the subsequent conditioning by Al2(SO4)3 dosing not only led to an increment of 18% in the portion of macromolecules in S-EPS, but also increased the zeta potential and D50 to -10.74 mV and 53.2 µm, respectively. The bound water content in sludge declined from 2.92 g/g DS to 1.98 g/g DS after combined conditioning. We concluded that DCCNa disintegrated the sludge flocs and microbial cells leading to the release of bound water, fine particles and organic substances with negative charge, and the fine colloidal particles can be flocculated into large dense aggregations with the dosing of Al2(SO4)3. In summary, the proposed combined conditioning provided a highly effective and environmental friendly approach to improve the sludge dewatering performance.

The Negative Cross-Talk between SAG/RBX2/ROC2 and APC/C E3 Ligases in Regulation of Cell Cycle Progression and Drug Resistance.

Anaphase-promoting complex/cyclosome (APC/C) is a well-characterized E3 ligase that couples with UBE2C and UBE2S E2s for substrate ubiquitylation by the K11 linkage. Our recent data show that SAG/RBX2/ROC2, a RING component of Cullin-RING E3 ligase, also complexes with these E2s for K11-linked substrate polyubiquitylation. Whether these two E3s cross-talk with each other was previously unknown. Here, we report that SAG competes with APC2 for UBE2C/UBE2S binding to act as a potential endogenous inhibitor of APC/C, thereby regulating the G2-to-M progression. As such, SAG knockdown triggers premature activation of APC/C, leading to mitotic slippage and resistance to anti-microtubule drugs. On the other hand, SAG itself is a substrate of APC/CCDH1 for targeted degradation at the G1 phase. The degradation-resistant mutant of SAG-R98A/L101A accelerates the G1-to-S progression. Our study reveals that the negative cross-talk between SAG and APC/C is likely a mechanism to ensure the fidelity of cell cycle progression.