Global genetic diversity and Asian clades evolution: a phylogeographic study of Staphylococcus aureus sequence type 5.

Staphylococcus aureus sequence type (ST) 5 has spread worldwide; however, phylogeographic studies on the evolution of global phylogenetic and Asian clades of ST5 are lacking. This study included 368 ST5 genome sequences, including 111 newly generated sequences. Primary phylogenetic analysis suggested that there are five clades, and geographical clustering of ST5 methicillin-resistant S. aureus (MRSA) was linked to the acquisition of S. aureus pathogenicity islands (SaPIs; enterotoxin gene island) and integration of the prophage φSa3. The most recent common ancestor of global S. aureus ST5 dates back to the mid-1940s, coinciding with the clinical introduction of penicillin. Bayesian phylogeographic inference allowed to ancestrally trace the Asian ST5 MRSA clade to Japan, which may have spread to major cities in China and Korea in the 1990s. Based on a pan-genome-wide association study, the emergence of Asian ST5 clades was attributed to the gain of prophages, SaPIs, and plasmids, as well as the coevolution of resistance genes. Clade IV displayed greater genomic diversity than the Asian MRSA clades. Collectively, our study provides in-depth insights into the global evolution of S. aureus ST5 mainly in China and the United States and reveals that different S. aureus ST5 clades have arisen independently in different parts of the world, with limited geographic dispersal across continents.

Balancing Flexible Side Chains on 2D Conjugated Acceptors Enables High-Performance Organic Solar Cell.

Balancing the rigid backbones and flexible side chains of light-harvesting materials is crucially important to reach optimized intermolecular packing, micromorphology, and thus photovoltaic performance of organic solar cells (OSCs). Herein, based on a distinctive CH-series acceptor platform with 2D conjugation extended backbones, a series of nonfullerene acceptors (CH-6F-Cn) are synthesized by delicately tuning the lengths of flexible side chains from n-octyl to n-amyl. A systemic investigation has revealed that the variation of the side chain's length can not only modulate intermolecular packing modes and crystallinity but also dramatically improve the micromorphology of the active layer and eventual photovoltaic parameters of OSCs. Consequently, the highest PCE of 18.73% can be achieved by OSCs employing D18:PM6:CH-6F-C8 as light-harvesting materials.

SIRT1 restores mitochondrial structure and function in rats by activating SIRT3 after cerebral ischemia/reperfusion injury.

Mitochondrial dysfunction contributes to cerebral ischemia-reperfusion (CI/R) injury, which can be ameliorated by Sirtuin-3 (SIRT3). Under stress conditions, the SIRT3-promoted mitochondrial functional recovery depends on both its activity and expression. However, the approach to enhance SIRT3 activity after CI/R injury remains unelucidated. In this study, Sprague-Dawley (SD) rats were intracranially injected with either adeno-associated viral Sirtuin-1 (AAV-SIRT1) or AAV-sh_SIRT1 before undergoing transient middle cerebral artery occlusion (tMCAO). Primary cortical neurons were cultured and transfected with lentiviral SIRT1 (LV-SIRT1) and LV-sh_SIRT1 respectively before oxygen-glucose deprivation/reoxygenation (OGD/R). Afterwards, rats and neurons were respectively treated with a selective SIRT3 inhibitor, 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP). The expression, function, and related mechanism of SIRT1 were investigated by Western Blot, flow cytometry, immunofluorescence staining, etc. After CI/R injury, SIRT1 expression decreased in vivo and in vitro. The simulation and immune-analyses reported strong interaction between SIRT1 and SIRT3 in the cerebral mitochondria before and after CI/R. SIRT1 overexpression enhanced SIRT3 activity by increasing the deacetylation of SIRT3, which ameliorated CI/R-induced cerebral infarction, neuronal apoptosis, oxidative stress, neurological and motor dysfunction, and mitochondrial respiratory chain dysfunction, promoted mitochondrial biogenesis, and retained mitochondrial integrity and mitochondrial morphology. Meanwhile, SIRT1 overexpression alleviated OGD/R-induced neuronal death and mitochondrial bioenergetic deficits. These effects were reversed by AAV-sh_SIRT1 and the neuroprotective effects of SIRT1 were partially offset by 3-TYP. These results suggest that SIRT1 restores the structure and function of mitochondria by activating SIRT3, offering neuroprotection against CI/R injury, which signifies a potential approach for the clinical management of cerebral ischemia.

Early prediction of sepsis-induced respiratory tract infection using a biomarker-based machine-learning algorithm.

Early and differential diagnosis of sepsis is essential to avoid unnecessary antibiotic use and further reduce patient morbidity and mortality. Here, we aimed to identify predictors of sepsis and advance a machine-learning strategy to predict sepsis-induced respiratory tract infection (RTI). Patients with sepsis and RTI were selected via retrospective analysis, and essential population characteristics and laboratory parameters were recorded. To improve the performance of the primary model and avoid over-fitting, a recursive feature elimination with cross-validation (RFECV) strategy was used to screen the optimal subset of biomarkers and construct nine machine-learning models based on this subset; the average accuracy, precision, recall, and F1-score were used for evaluation of the models. We identified 430 patients with sepsis and 686 patients with RTI. A total of 39 features were collected, with 23 features identified for initial model construction. Using the RFECV algorithm, we found that the XGBoost classifier, which only needed to include seven biomarkers, demonstrated the best performance among all prediction models, with an average accuracy of 89.24 ± 2.28, while the Ridge classifier, which included 11 biomarkers, had an average accuracy of only 83.87 ± 4.69. The remaining models had prediction accuracies greater than 88%. We developed nine models for predicting sepsis using a strategy that combined RFECV with machine learning. Among these models, the XGBoost classifier, which included seven biomarkers, showed the best performance and highest accuracy for predicting sepsis and may be a promising tool for the timely identification of sepsis.

Biodirected Screening and Preparation of Larimichthys crocea Angiotensin-I-Converting Enzyme-Inhibitory Peptides by a Combined In Vitro and In Silico Approach.

Food-derived angiotensin-I-converting enzyme (ACE)-inhibitory peptides have gained attention for their potent and safe treatment of hypertensive disorders. However, there are some limitations of conventional methods for preparing ACE-inhibitory peptides. In this study, in silico hydrolysis, the quantitative structure-activity relationship (QSAR) model, LC-MS/MS, inhibition kinetics, and molecular docking were used to investigate the stability, hydrolyzability, in vitro activity, and inhibition mechanism of bioactive peptides during the actual hydrolysis process. Six novel ACE-inhibitory peptides were screened from the Larimichthys crocea protein (LCP) and had low IC50 values (from 0.63 ± 0.09 µM to 10.26 ± 0.21 µM), which were close to the results of the QSAR model. After in vitro gastrointestinal simulated digestion activity of IPYADFK, FYEPFM and NWPWMK were found to remain almost unchanged, whereas LYDHLGK, INEMLDTK, and IHFGTTGK were affected by gastrointestinal digestion. Meanwhile, the inhibition kinetics and molecular docking results were consistent in that ACE-inhibitory peptides of different inhibition forms could effectively bind to the active or non-central active centers of ACE through hydrogen bonding. Our proposed method has better reproducibility, accuracy, and higher directivity than previous methods. This study can provide new approaches for the deep processing, identification, and preparation of Larimichthys crocea.

Klebsiella quasipneumoniae in intestine damages bile acid metabolism in hematopoietic stem cell transplantation patients with bloodstream infection.

BACKGROUND: Bloodstream infection (BSI) is a serious hematopoietic stem cell transplantation (HSCT) complication. The intestinal microbiome regulates host metabolism and maintains intestinal homeostasis. Thus, the impact of microbiome on HSCT patients with BSI is essential. METHODS: Stool and serum specimens of HSCT patients were prospectively collected from the pretransplant conditioning period till 4 months after transplantation. Specimens of 16 patients without BSI and 21 patients before BSI onset were screened for omics study using 16S rRNA gene sequencing and untargeted metabolomics. The predictive infection model was constructed using LASSO and the logistic regression algorithm. The correlation and influence of microbiome and metabolism were examined in mouse and Caco-2 cell monolayer models. RESULTS: The microbial diversity and abundance of Lactobacillaceae were remarkably reduced, but the abundance of Enterobacteriaceae (especially Klebsiella quasipneumoniae) was significantly increased in the BSI group before onset, compared with the non-BSI group. The family score of microbiome features (Enterobacteriaceae and Butyricicoccaceae) could highly predict BSI (AUC = 0.879). The serum metabolomic analysis showed that 16 differential metabolites were mainly enriched in the primary bile acid biosynthesis pathway, and the level of chenodeoxycholic acid (CDCA) was positively correlated with the abundance of K. quasipneumoniae (R = 0.406, P = 0.006). The results of mouse experiments confirmed that three serum primary bile acids levels (cholic acid, isoCDCA and ursocholic acid), the mRNA expression levels of bile acid farnesol X receptor gene and apical sodium-dependent bile acid transporter gene in K. quasipneumoniae colonized mice were significantly higher than those in non-colonized mice. The intestinal villus height, crypt depth, and the mRNA expression level of tight junction protein claudin-1 gene in K. quasipneumoniae intestinal colonized mice were significantly lower than those in non-colonized mice. In vitro, K. quasipneumoniae increased the clearance of FITC-dextran by Caco-2 cell monolayer. CONCLUSIONS: This study demonstrated that the intestinal opportunistic pathogen, K. quasipneumoniae, was increased in HSCT patients before BSI onset, causing increased serum primary bile acids. The colonization of K. quasipneumoniae in mice intestines could lead to mucosal integrity damage. The intestinal microbiome features of HSCT patients were highly predictive of BSI and could be further used as potential biomarkers.

Neuropilin-1 promotes mitochondrial structural repair and functional recovery in rats with cerebral ischemia.

OBJECTIVES: Available literature documents that ischemic stroke can disrupt the morphology and function of mitochondria and that the latter in other disease models can be preserved by neuropilin-1 (NRP-1) via oxidative stress suppression. However, whether NRP-1 can repair mitochondrial structure and promote functional recovery after cerebral ischemia is still unknown. This study tackled this very issue and explored the underlying mechanism. METHODS: Adeno-associated viral (AAV)-NRP-1 was stereotaxically inoculated into the cortex and ipsilateral striatum posterior of adult male Sprague-Dawley (SD) rats before a 90-min transient middle cerebral artery occlusion (tMCAO) and subsequent reperfusion. Lentivirus (LV)-NRP-1 was transfected into rat primary cortical neuronal cultures before a 2-h oxygen-glucose deprivation and reoxygenation (OGD/R) injury to neurons. The expression and function of NRP-1 and its specific protective mechanism were investigated by Western Blot, immunofluorescence staining, flow cytometry, magnetic resonance imaging, transmission electron microscopy, etc. The binding was detected by molecular docking and molecular dynamics simulation. RESULTS: Both in vitro and in vivo models of cerebral ischemia/reperfusion (I/R) injury presented a sharp increase in NRP-1 expression. The expression of AAV-NRP-1 markedly ameliorated the cerebral I/R-induced damage to the motor function and restored the mitochondrial morphology. The expression of LV-NRP-1 alleviated mitochondrial oxidative stress and bioenergetic deficits. AAV-NRP-1 and LV-NRP-1 treatments increased the wingless integration (Wnt)-associated signals and ß-catenin nuclear localization. The protective effects of NRP-1 were reversed by the administration of XAV-939. CONCLUSIONS: NRP-1 can produce neuroprotective effects against I/R injury to the brain by activating the Wnt/ß-catenin signaling pathway and promoting mitochondrial structural repair and functional recovery, which may serve as a promising candidate target in treating ischemic stroke.

Improved Sleep Affects Epigastric Pain in Functional Dyspepsia by Reducing the Levels of Inflammatory Mediators.

INTRODUCTION: The pathogenesis of epigastric pain in functional dyspepsia (FD) is complex. The study aims to explore the effect of sleep improvement on this symptom. METHODS: In total, 120 patients with FD-associated epigastric pain and insomnia were randomly divided into experimental and control groups using the envelope method. After applying the exclusion criteria, 107 patients were enrolled in the experimental (56 patients) and control (51 patients) groups. Insomnia was graded according to the Pittsburgh Sleep Quality Index (PSQI). In the experimental group, eszopiclone 3 mg, eszopiclone 3 mg + estazolam 1 mg, and eszopiclone 3 mg + estazolam 2 mg were given to patients with mild, moderate, and severe insomnia, respectively. In the control group, patients were given 1, 2, or 3 tablets of vitamin B complex. Patient sleep quality was monitored with Sleepthing. Epigastric pain was evaluated with a Numeric Rating Scale. The serum levels of IL-1ß, IL-6, IL-8, and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay. Pain scores, sleep parameters, and serum levels of inflammatory mediators were compared before and after treatment. RESULTS: After treatment, the pain scores, sleep parameters, and TNF-α and IL-6 levels in the experimental group were significantly lower than those in the control group (p < 0.05). PSQI insomnia scores were significantly associated with pain scores, IL-6, and TNF-α (p < 0.05) but not in IL-8 and IL-1ß levels (p > 0.05) among the three groups. CONCLUSIONS: Improving sleep with eszopiclone and/or estazolam alleviates FD-associated epigastric pain, possibly by inhibiting related downstream transmission pathways and reducing the release of inflammatory mediators.

Developing a machine learning prediction algorithm for early differentiation of urosepsis from urinary tract infection.

OBJECTIVES: Early recognition and timely intervention for urosepsis are key to reducing morbidity and mortality. Blood culture has low sensitivity, and a long turnaround time makes meeting the needs of clinical diagnosis difficult. This study aimed to use biomarkers to build a machine learning model for early prediction of urosepsis. METHODS: Through retrospective analysis, we screened 157 patients with urosepsis and 417 patients with urinary tract infection. Laboratory data of the study participants were collected, including data on biomarkers, such as procalcitonin, D-dimer, and C-reactive protein. We split the data into training (80%) and validation datasets (20%) and determined the average model prediction accuracy through cross-validation. RESULTS: In total, 26 variables were initially screened and 18 were statistically significant. The influence of the 18 variables was sorted using three ranking methods to further determine the best combination of variables. The Gini importance ranking method was found to be suitable for variable filtering. The accuracy rates of the six machine learning models in predicting urosepsis were all higher than 80%, and the performance of the artificial neural network (ANN) was the best among all. When the ANN included the eight biomarkers with the highest influence ranking, its model had the best prediction performance, with an accuracy rate of 92.9% and an area under the receiver operating characteristic curve of 0.946. CONCLUSIONS: Urosepsis can be predicted using only the top eight biomarkers determined by the ranking method. This data-driven predictive model will enable clinicians to make quick and accurate diagnoses.

Neglected methane production and toxicity risk in low-frequency ultrasound for controlling harmful algal blooms.

Algal blooms are regarded as a significant source of CH4 emissions. Ultrasound has been gradually employed as a fast and efficient algae removal technology in recent years. However, the changes in water environment and potential ecological effects caused by ultrasonic algae removal are not fully clear. Here, a 40-day microcosm study was performed to simulate the collapse of Microcystis aeruginosa blooms after ultrasonic treatment. The results showed that low-frequency ultrasound at 29.4 kHz for 15 min removed 33.49% of M. aeruginosa and contributed to the destruction of cell structure, but it intensified the leakage of intracellular algal organic matter and microcystins. The accelerated collapse of M. aeruginosa blooms after ultrasonication promoted the rapid formation of anaerobic and reductive methanogenesis conditions, and elevated dissolved organic carbon content. Moreover, the release of labile organics, including tyrosine, tryptophan, protein-like compositions, and aromatic proteins, was facilitated by the collapse of M. aeruginosa blooms after ultrasonic treatment, and they supported the growth of anaerobic fermentation bacteria and hydrogenotrophic Methanobacteriales. This was also demonstrated by the increase in methyl-coenzyme M reductase (mcrA) genes in sonicated algae added treatments at the end of incubation. Finally, the CH4 production in sonicated algae added treatments was 1.43-fold higher than that in non-sonicated algae added treatments. These observations suggested that ultrasound for algal bloom control potentially increased the toxicity of treated water and its greenhouse gas emissions. This study can provide new insights and guidance to evaluate environmental effects of ultrasonic algae removal.

Deep Reinforcement Learning-Based One-to-Multiple Cooperative Computing in Large-Scale Event-Driven Wireless Sensor Networks.

Emergency event monitoring is a hot topic in wireless sensor networks (WSNs). Benefiting from the progress of Micro-Electro-Mechanical System (MEMS) technology, it is possible to process emergency events locally by using the computing capacities of redundant nodes in large-scale WSNs. However, it is challenging to design a resource scheduling and computation offloading strategy for a large number of nodes in an event-driven dynamic environment. In this paper, focusing on cooperative computing with a large number of nodes, we propose a set of solutions, including dynamic clustering, inter-cluster task assignment and intra-cluster one-to-multiple cooperative computing. Firstly, an equal-size K-means clustering algorithm is proposed, which activates the nodes around event location and then divides active nodes into several clusters. Then, through inter-cluster task assignment, every computation task of events is alternately assigned to the cluster heads. Next, in order to make each cluster efficiently complete the computation tasks within the deadline, a Deep Deterministic Policy Gradient (DDPG)-based intra-cluster one-to-multiple cooperative computing algorithm is proposed to obtain a computation offloading strategy. Simulation studies show that the performance of the proposed algorithm is close to that of the exhaustive algorithm and better than other classical algorithms and the Deep Q Network (DQN) algorithm.

Response of aerobic activated sludge to edible oil exposure: Extracellular polymeric substance (EPS) characteristics and microbial community.

Aerobic activated sludge is widely used to degrade edible oil wastewater in wastewater treatment plants. During this process, the observed poor organics removal performance might be caused by poor sludge settling performance, which might be influenced by extracellular polymeric substances (EPS) and the structure of the microbial community. However, this hypothesis was not confirmed. Thus, this study investigated the response of activated sludge to 50% and 100% edible oil exposure in comparison to glucose, focusing on organics removal performance, characteristics of sludge, EPS, and microbial community structure. Results showed that both concentrations of edible oil influenced the systems' performance, although 100% edible oil showed more significant negative effects than 50% edible oil. The mechanisms behind the influence of edible oil on the aerobic activated sludge system and the differences between the different concentrations of edible oil were revealed. The worse system performance in the edible oil exposure system was due to the worse sludge settling performance, which was significantly affected by edible oil (p < 0.05). The sludge settling performance was mainly inhibited by promoting the formation of floating particles and the enrichment of filamentous bacteria in the 50% edible oil exposure system; biosurfactant secretion was also speculated as the reason, in addition to the above factors, in the 100% edible oil exposure system. The macroscopic largest floating particles, highest total relative abundance of foaming bacteria and biosurfactant production genera (34.32%), lowest surface tension (43.7 mN/m), and highest emulsifying activity (E24 = 25%) of EPS in 100% edible oil exposure systems provide strong evidence.

Terminally Chlorinated and Thiophene-linked Acceptor-Donor-Acceptor Structured 3D Acceptors with Versatile Processability for High-efficiency Organic Solar Cells.

To exploit the potential of our newly developed three-dimensional (3D) dimerized acceptors, a series of chlorinated 3D acceptors (namely CH8-3/4/5) were reported by precisely tuning the position of chlorine (Cl) atom. The introduction of Cl atom in central unit affects the molecular conformation. Whereas, by replacing fluorinated terminal groups (CH8-3) with chlorinated terminal groups (CH8-4 and CH8-5), the red-shift absorption and enhanced crystallization are achieved. Benefiting from these, all devices received promising power conversion efficiencies (PCEs) over 16 % as well as decent thermal/photo-stabilities. Among them, PM6:CH8-4 based device yielded a best PCE of 17.58 %. Besides, the 3D merits with multi alkyl chains enable their versatile processability during the device preparation. Impressive PCEs of 17.27 % and 16.23 % could be achieved for non-halogen solvent processable devices prepared in glovebox and ambient, respectively. 2.88 cm2 modules also obtained PCEs over 13 % via spin-coating and blade-coating methods, respectively. These results are among the best performance of dimerized acceptors. The decent performance of CH8-4 on small-area devices, modules and non-halogen solvent-processed devices highlights the versatile processing capability of our 3D acceptors, as well as their potential applications in the future.

Electronic Configuration Tuning of Centrally Extended Non-Fullerene Acceptors Enabling Organic Solar Cells with Efficiency Approaching 19 .

In the molecular optimizations of non-fullerene acceptors (NFAs), extending the central core can tune the energy levels, reduce nonradiative energy loss, enhance the intramolecular (donor-acceptor and acceptor-acceptor) packing, facilitate the charge transport, and improve device performance. In this study, a new strategy was employed to synthesize acceptors featuring conjugation-extended electron-deficient cores. Among these, the acceptor CH-BBQ, embedded with benzobisthiadiazole, exhibited an optimal fibrillar network morphology, enhanced crystallinity, and improved charge generation/transport in blend films, leading to a power conversion efficiency of 18.94 % for CH-BBQ-based ternary organic solar cells (OSCs; 18.19 % for binary OSCs) owing to its delicate structure design and electronic configuration tuning. Both experimental and theoretical approaches were used to systematically investigate the influence of the central electron-deficient core on the properties of the acceptor and device performance. The electron-deficient core modulation paves a new pathway in the molecular engineering of NFAs, propelling relevant research forward.

Electrically Controllable Kondo Correlation in Spin-Orbit-Coupled Quantum Point Contacts.

Integrating the Kondo correlation and spin-orbit interactions, each of which have individually offered unprecedented means to manipulate electron spins, in a controllable way can open up new possibilities for spintronics. We demonstrate electrical control of the Kondo correlation by coupling the bound spin to leads with tunable Rashba spin-orbit interactions, realized in semiconductor quantum point contacts. We observe a transition from single to double peak zero-bias anomalies in nonequilibrium transport-the manifestation of the Kondo effect-indicating a controlled Kondo spin reversal using only spin-orbit interactions. Universal scaling of the Kondo conductance is demonstrated, implying that the spin-orbit interactions could enhance the Kondo temperature. A theoretical model based on quantum master equations is also developed to calculate the nonequilibrium quantum transport.

Complete pathological response with diabetic ketoacidosis to the combination of sintilimab and anlotinib in an unresectable hepatocellular carcinoma patient: a case report.

Most hepatocellular carcinoma (HCC) patients have dismal prognoses because they are already in the advanced stage at the time of initial diagnosis and are unable to undergo upfront surgery. Recent studies of immune checkpoint inhibitors (ICIs) and antiangiogenic agents (AAAs) have shown encouraging results for unresectable HCC (uHCC). Here, we report a patient with uHCC who was treated with a combination of anlotinib and sintilimab (sintilimab 200 mg, intravenous glucose tolerance test, q21d and anlotinib 12 mg, orally, d1-14, q21d), an analog of the combination of lenvatinib and pembrolizumab with much lower cost. The patient with recurrent uHCC was downstaged to resectable disease by the combination therapy. After eight cycles of treatment with anlotinib and sintilimab, the patient underwent a second operation. The histology of the resected mass revealed a major and almost complete pathological response. However, this patient was diagnosed with type I diabetes mellitus with ketoacidosis after nearly 10 cycles of combination treatment with anlotinib and sintilimab. Active follow-ups revealed no signs of local recurrence or distant failure. In conclusion, this case report demonstrated that the combination of anlotinib and sintilimab, one of the strategies combining ICIs with AAAs, showed promising efficacy in the treatment of uHCC patients.

UAV Enhanced Target-Barrier Coverage Algorithm for Wireless Sensor Networks Based on Reinforcement Learning.

Target-barrier coverage is a newly proposed coverage problem in wireless sensor networks (WSNs). The target-barrier is a closed barrier with a distance constraint from the target, which can detect intrusions from outside. In some applications, detecting intrusions from outside and monitoring the targets inside the barrier is necessary. However, due to the distance constraint, the target-barrier fails to monitor and detect the target breaching from inside in a timely manner. In this paper, we propose a convex hull attraction (CHA) algorithm to construct the target-barrier and a UAV-enhanced coverage (QUEC) algorithm based on reinforcement learning to cover targets. The CHA algorithm first divides the targets into clusters, then constructs the target-barrier for the outermost targets of the clusters, and the redundant sensors replace the failed sensors. Finally, the UAV's path is planned based on QUEC. The UAV always covers the target, which is most likely to breach. The simulation results show that, compared with the target-barrier construction algorithm (TBC) and the virtual force algorithm (VFA), CHA can reduce the number of sensors required to construct the target-barrier and extend the target-barrier lifetime. Compared with the traveling salesman problem (TSP), QUEC can reduce the UAV's coverage completion time, improve the energy efficiency of UAV and the efficiency of detecting targets breaching from inside.

Application of Fenton sludge coupled hydrolysis acidification in pretreatment of wastewater containing PVA: Performance and mechanisms.

Hydrolysis acidification (HA) is widely used in pretreatment of macromolecular refractory wastewater to improve its biodegradability. However, because the biological activity could be inhibited by macromolecular substances to a certain extent, its application is limited. In this study, polyvinyl alcohol (PVA), as a classic macromolecular pollutant in TPD wastewater, was treated by the Fenton sludge-coupled HA process to investigate the effects of Fenton sludge addition on the HA performance and identify the probable mechanisms behind it. The results showed that approximately 40% of macromolecular PVA was hydrolyzed into small molecular substances with molecular weight (Mw) < 105 in the Fenton sludge-added reactor. Meanwhile, acidification efficiency (AE), volatile fatty acid production increased by 20.8% and 92.05 mg/L with Fenton sludge addition. The values of BOD5/COD changed from 0.091 of influent to 0.26 and 0.32 of effluent from the simple HA process and Fenton sludge addition HA process, respectively. These results proved that biodegradability was improved by the two processes and the Fenton sludge addition had a positive effect on HA. Further analysis found that 2-lines ferrihydrite involved in Fenton sludge might serve as an electron acceptor to participate in extracellular respiratory. Besides, the Fe2+ observed a positive effect of the sludge characteristics in agreement with the higher activity of dehydrogenase and extracellular polymeric substances (EPS) production. This study suggested that Fenton sludge can be recycled and used as an iron source to enhance HA for industrial wastewater pretreatment.

Novel insights into aerobic duration control-based partial nitritation in source-separated blackwater treatment: Growth type, inoculation source, and comammox threat.

Aerobic duration control (ADC), whereby aeration is terminated before nitrite is extremely oxidized during the nitrification process, is an effective strategy to achieve partial nitritation (PN) for blackwater. This study evaluated the effects of microbial growth type, influent ammonia-oxidizing organisms (AOO), and comammox bacteria from seeding sludge to ADC-based PN. The long-term operation of lab-scale reactors and model simulations were implemented to select the best growth type. The biofilm formed on the inner wall of the activated sludge reactor decreased the nitrite accumulation ratio (NAR) from 99.2% to 77.2%. Meanwhile, the NAR of the pure-biofilm reactor decreased from 95.9% to 47.8%. The deteriorated PN of the biofilm-related reactors was due to the extended solid retention time and increased substrate saturation constants of AOOs compared with those of nitrite-oxidizing organisms (NOO). Periodic biofilm carrier regeneration and biofilm thickness control can recover PN performance but are difficult to implement. In contrast, the optimized activated sludge reactor exhibited high (NAR >94%) and stable (>3 months) PN performance when treating real blackwater. Nitrifiers were found in blackwater, and chemically enhanced high-rate activated sludge pretreatment removed more NOOs than AOOs (41.8% vs. 24.3%) and increased the influent AOO/NOO ratio. Interestingly, the influent AOOs supported fast PN start-up in the moving-bed biofilm reactor without the initial inoculation of activated sludge. Moreover, model simulations verified that high and stable PN could also be realized in an activated sludge reactor by the continuous inoculation of influent AOOs, which is a novel PN start-up strategy. Metagenomic analyses showed that the comammox bacteria from the seeding sludge eventually disappeared owing to their intrinsic specific growth rates and free ammonia inhibition. The findings of this study will provide insightful guidelines for PN application in decentralized and semi-centralized wastewater treatment systems.

Central Unit Fluorination of Non-Fullerene Acceptors Enables Highly Efficient Organic Solar Cells with Over 18 % Efficiency.

Halogenation of terminal of acceptors has been shown to give dramatic improvements in power conversion efficiencies (PCEs) of organic solar cells (OSCs). Similar significant results could be expected from the halogenation of the central units of state-of-the-art Y-series acceptors. Herein, a pair of acceptors, termed CH6 and CH4, featuring a conjugation-extended phenazine central unit with and without fluorination, have been synthesized. The fluorinated CH6 has enhanced molecular interactions and crystallinity, superior fibrillar network morphology and improved charge generation and transport in blend films, thus affording a higher PCE of 18.33 % for CH6-based binary OSCs compared to 16.49 % for the non-fluorinated CH4. The new central site offers further opportunities for structural optimization of Y-series molecules to afford better-performed OSCs and reveals the effectiveness of fluorination on central units.