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Handedness is an essential attribute of chiral nanocrystals, having a major influence on their properties. During chemical growth, the handedness of nanocrystals is usually tuned by selecting the corresponding enantiomer of chiral molecules involved in asymmetric growth, often known as chiral inducers. We report that, even using the same chiral inducer enantiomer, the handedness of chiral gold nanocrystals can be reversed by using Au nanorod seeds with either single crystalline or pentatwinned structure. This effect holds for chiral growth induced both by amino acids and by chiral micelles. Although it was challenging to discern the morphological handedness for L‐cystine‐directed particles, even using electron tomography, both cases showed circular dichroism bands of opposite sign, with nearly mirrored chiroptical signatures for chiral micelle‐directed growth, along with quasi‐helical wrinkles of inverted handedness. These results expand the chiral growth toolbox with an effect that might be exploited to yield a host of interesting morphologies with tunable optical properties. [ABSTRACT FROM AUTHOR]

Handedness is an essential attribute of chiral nanocrystals, having a major influence on their properties. During chemical growth, the handedness of nanocrystals is usually tuned by selecting the corresponding enantiomer of chiral molecules involved in asymmetric growth, often known as chiral inducers. We report that, even using the same chiral inducer enantiomer, the handedness of chiral gold nanocrystals can be reversed by using Au nanorod seeds with either single crystalline or pentatwinned structure. This effect holds for chiral growth induced both by amino acids and by chiral micelles. Although it was challenging to discern the morphological handedness for L‐cystine‐directed particles, even using electron tomography, both cases showed circular dichroism bands of opposite sign, with nearly mirrored chiroptical signatures for chiral micelle‐directed growth, along with quasi‐helical wrinkles of inverted handedness. These results expand the chiral growth toolbox with an effect that might be exploited to yield a host of interesting morphologies with tunable optical properties. [ABSTRACT FROM AUTHOR]

SUMMARY: Rhus chinensis Mill., an economically valuable Anacardiaceae species, is parasitized by the galling aphid Schlechtendalia chinensis, resulting in the formation of the Chinese gallnut (CG). Here, we report a chromosomal‐level genome assembly of R. chinensis, with a total size of 389.40 Mb and scaffold N50 of 23.02 Mb. Comparative genomic and transcriptome analysis revealed that the enhanced structure of CG and nutritional metabolism contribute to improving the adaptability of R. chinensis to S. chinensis by supporting CG and galling aphid growth. CG was observed to be abundant in hydrolysable tannins (HT), particularly gallotannin and its isomers. Tandem repeat clusters of dehydroquinate dehydratase/shikimate dehydrogenase (DQD/SDH) and serine carboxypeptidase‐like (SCPL) and their homologs involved in HT production were determined as specific to HT‐rich species. The functional differentiation of DQD/SDH tandem duplicate genes and the significant contraction in the phenylalanine ammonia‐lyase (PAL) gene family contributed to the accumulation of gallic acid and HT while minimizing the production of shikimic acid, flavonoids, and condensed tannins in CG. Furthermore, we identified one UDP glucosyltransferase (UGT84A), three carboxylesterase (CXE), and six SCPL genes from conserved tandem repeat clusters that are involved in gallotannin biosynthesis and hydrolysis in CG. We then constructed a regulatory network of these genes based on co‐expression and transcription factor motif analysis. Our findings provide a genomic resource for the exploration of the underlying mechanisms of plant‐galling insect interaction and highlight the importance of the functional divergence of tandem duplicate genes in the accumulation of secondary metabolites. [ABSTRACT FROM AUTHOR]

Out of the total cases of cervical cancer, brain metastases (BMs) are relatively rare, with an estimated incidence rate of 0.63% (range: 0.1%–2.2%). Additionally, BMs prognosis remains poor, and the average patient survival time following a BM diagnosis is 3 to 5 months. Few studies have addressed the effect of programmed cell death‐1 inhibitors against BMs in cervical cancer, although they are an established option for recurrent/metastatic disease. Hence, we report a case involving a 54‐year‐old post‐surgery patient with cervical cancer with a body mass index of 19.5 kg/m2 and Eastern Collaborative Oncology Group (ECOG) performance status of 3; the disease recurred with BMs 1 year later. Intensity‐modulated radiation therapy concurrent with temozolomide and bevacizumab was initiated, following which zimberelimab immunotherapy combined with anlotinib was administered to extend tumor control. The patient had a progression‐free survival duration of 10 months, the tumor response was assessed as a partial response based on the evaluation criteria for solid tumors (RECIST1.1), and the ECOG status improved to 1 after therapy. These findings suggest that immunotherapy‐based combination therapy following radiotherapy may be a good choice for patients with cervical cancer and BMs. [ABSTRACT FROM AUTHOR]

Spinal cord stimulation (SCS) and dorsal root entry zone (DREZ) lesioning are important therapeutic options for intractable post-traumatic neuropathic pain (PNP). However, surgical choice is controversial due to the need to maximize pain relief and reduce complications. This study aims to retrospectively analyze the effect and complications of DREZ lesioning for patients with PNP who were unresponsive to SCS and provide a surgical reference. Demographic data and surgical characteristics of patients with PNP who underwent DREZ lesioning after an unresponsive SCS were reviewed. Long-term outcomes including numeric rating scale, global impression of change, and long-term complications were assessed. Kaplan-Meier analysis was used to evaluate pain-free survival. Of 19 patients with PNP, 8 had brachial plexus injury (BPI), 7 had spinal cord injury, 2 had cauda equina injury, 1 had intercostal nerve injury, and 1 had lumbosacral plexus injury. All patients were unresponsive or had a recurrence of pain after SCS, with an average pain-relief rate of 9.3%. After DREZ lesioning, the mean numeric rating scale scores significantly decreased from 7.6 ± 1.5 to 1.8 ± 1.7, with an average pain-relief rate of 75.3%. Seven patients (36.8%) experienced worsened neurologic dysfunction at the last follow-up. Patients with BPI had a significantly better outcome than other pathologies (P < 0.001) after DREZ lesioning. DREZ lesioning is an effective alternative procedure to SCS for patients with PNP who have lost limb function. Particularly for those with BPI, DREZ lesioning has shown good efficacy and can be considered a preferred surgical option. [ABSTRACT FROM AUTHOR]

The growth of crystalline nanoparticles (NPs) generally involves three processes: nucleation, growth, and shape evolution. Among them, the shape evolution is less understood, despite the importance of morphology for NP properties. Here, we propose a symmetry‐based kinematic theory (SBKT) based on classical growth theories to illustrate the process. Based on the crystal lattice, nucleus (or seed) symmetry, and the preferential growth directions under the experimental conditions, the SBKT can illustrate the growth trajectories. The theory accommodates the conventional criteria of the major existing theories for crystal growth and provides tools to better understand the symmetry‐breaking process during the growth of anisotropic structures. Furthermore, complex dendritic growth is theoretically and experimentally demonstrated. Thus, it provides a framework to explain the shape evolution, and extends the morphogenesis prediction to cases, which cannot be treated by other theories. [ABSTRACT FROM AUTHOR]

Das Wachstum von kristallinen Nanopartikeln (NP) umfasst im Allgemeinen drei Prozesse: Keimbildung, Wachstum und die Entwicklung der Form. Von diesen Prozessen ist die Formentwicklung trotz der Bedeutung der Morphologie für die Eigenschaften der NP am wenigsten verstanden. Hier beschreiben wir eine symmetriebasierte kinematische Theorie (SBKT) die auf klassischen Wachstumstheorien basiert, um den Prozess zu veranschaulichen. Auf Grundlage des Kristallgitters, der Keim‐ (oder Kern‐) Symmetrie und der bevorzugten Wachstumsrichtungen unter den experimentellen Bedingungen kann die SBKT die Wachstumstrajektorien veranschaulichen. Die Theorie erfüllt die konventionellen Kriterien der wichtigsten bestehenden Theorien für das Kristallwachstum und bietet Werkzeuge zum besseren Verständnis des Symmetriebrechens während des Wachstums anisotroper Strukturen. Darüber hinaus wird das komplexe dendritische Wachstum sowohl theoretisch als auch experimentell nachgewiesen. Damit bietet sie einen Ansatz zur Erklärung der Formentwicklung und erweitert die Vorhersage der Morphogenese auf Fälle, die von anderen Theorien nicht erfasst werden können. [ABSTRACT FROM AUTHOR]

Background: Microvascular decompression (MVD) is known as a safe and effective procedure to treat glossopharyngeal neuralgia (GN). However, some patients experienced poor pain relief after MVD, for which the mechanism is not clear yet. Reviewing the intraoperative findings and postoperative effect of reoperation for patients who failed the first MVD, is helpful to figure out why the first MVD for GN failed. Methods: There were eight patients with GN who failed first MVD. The possibilities for secondary GN were eliminated by physical and radiological examination. The reoperation through the previous incision was conducted, and appropriately, treatment was provided according to the intraoperative findings. The video data and prognosis of the reoperation were retrospectively reviewed. The reasons for the invalid first MVD were analyzed. Results: To the end of follow-up, there were 7 patients of pain-free, and one patient with occasional mild pain attacks (VAS 2). There was one patient who experienced transient hoarseness in 3 months after the reoperation. We summarized the causes for failed first MVD which were omission of the offending vessel in 3 cases, inadequate decompression of the nerve root in 2 cases, and excessive decompression materials which caused iatrogenic nerve root compression in 3 cases. Conclusions: For patients with recurrent or failed after MVD, a thorough examination should be carried out to eliminate the possibility of secondary GN. Reoperation through the previous incision is safe and effective. The bone window should be close enough to the sigmoid sinus to aid the exposure of the nerve root. The nerve transection could be adopted if no offending vessels were found. And a multi-site decompression could be used when the vertebral artery is the offending vessel. [ABSTRACT FROM AUTHOR]

The global atmospheric CO2 concentration reached 147% of pre‐industrial levels in 2019, and is still increasing with an accelerated rate. A series of methods have been developed to convert CO2 to other non‐greenhouse molecules. Elelctrocatalytic CO2 reduction reaction (CO2RR) is one of the promising methods, since it could support renewable energy. Optimizing the CO2RR system requires finding highly efficient catalysts, as well as electrolysis systems. In this essay, the development of promising heterogeneous catalysts with well‐defined active metal sites is discussed. These catalysts could be prepared by immobilizing metal cations onto chemically well‐defined substrates, such as metal‐organic frameworks, covalent‐organic frameworks, polyoxometalates, or immobilizing well‐defined molecular catalysts on conducting substrates. A clear perspective on the catalyst's structures contributes to the understanding of structure‐reactivity correlations, which could, in turn, shed light on designing better catalysts. Some methods to assist the electrocatalysis process, such as coupling with solar or heat energy, are also briefly discussed. [ABSTRACT FROM AUTHOR]

Aerobic digestion followed by dewatering is a widely applied method for sludge stabilization and reduction in decentralized wastewater treatment plants. It is important to enhance the sludge dewaterability of the aerobically digested sludge due to its considerable impact on cost of sludge disposal and management. In this study, an innovative technique is developed for improving the dewaterability of aerobically digested sludge by combined conditioning with persulfate (PS) and zero valent iron (ZVI). The results demonstrated that the dewaterability of aerobically digested sludge could be significantly enhanced with the PS and ZVI dosage in the range of 0–0.5 g/gTS and 0–0.4 g/gTS, respectively. The highest improvement was achieved at 0.05 g ZVI/g TS with 0.1 g PS/g TS, and the capillary suction time was reduced by ∼80%. The extracellular polymeric substances (EPS) characterization revealed that the combined PS-ZVI treatment could largely reduce proteins, polysaccharides and humic acids-like compounds in the tightly bounded EPS of the aerobically digested sludge, leading to bound water releasing from sludge flocs. The recovery of the ZVI particles could reach around 45%–80% after the treatment, further proved the sustainability of the approach. The proposed PS-ZVI conditioning would not have significant impact on the final choice of sludge disposal and the mainstream wastewater treatment. However, plant-scale test are still required for better assessing the proposed technique. Image 1 • Persulfate-ZVI conditioning enhanced the dewaterability of aerobically digested sludge. • Capillary suction time reduced by 80% at 0.05 g ZVI/g TS and 0.1 g persulfate/g TS. • Persulfate-ZVI treatment reduced the hydrophilic organic compounds in TB-EPS. • ZVI could be recovered and the cost for sludge disposal could be reduced. [ABSTRACT FROM AUTHOR]

• A literature review on biological processes in MBR models is presented. • There are still gaps in the literature due to EPS complex nature and multiple origins. • SMP and EPS modelling data are derived from an experimental estimation. • Accurate estimation of SMP and EPS can contribute to optimizing membrane fouling. A mathematical correlation between biomass kinetic and membrane fouling can improve the understanding and spread of Membrane Bioreactor (MBR) technology, especially in solving the membrane fouling issues. On this behalf, this paper, produced by the International Water Association (IWA) Task Group on Membrane modelling and control, reviews the current state-of-the-art regarding the modelling of kinetic processes of biomass, focusing on modelling production and utilization of soluble microbial products (SMP) and extracellular polymeric substances (EPS). The key findings of this work show that the new conceptual approaches focus on the role of different bacterial groups in the formation and degradation of SMP/EPS. Even though several studies have been published regarding SMP modelling, there still needs to be more information due to the highly complicated SMP nature to facilitate the accurate modelling of membrane fouling. The EPS group has seldom been addressed in the literature, probably due to the knowledge deficiency concerning the triggers for production and degradation pathways in MBR systems, which require further efforts. Finally, the successful model applications showed that proper estimation of SMP and EPS by modelling approaches could optimise membrane fouling, which can influence the MBR energy consumption, operating costs, and greenhouse gas emissions. [Display omitted] [ABSTRACT FROM AUTHOR]

The nitrifying systems have been reported to be able to biodegrade micropollutants, yet it is still unclear about the cometabolism of ammonia-oxidizing bacteria (AOB) towards micropollutants, in particular their enzyme and transcriptional responses under exposure of micropollutants. This study investigated cometabolic biodegradation of a selected antibiotic, cephalexin (CFX), by an enriched nitrifying culture through a series of batch experiments, together with the assessments of enzymatic activity, key gene expression, and biotoxicity of the degradation products. More than 99% CFX with an initial concentration of 50 μg/L could be removed with the presence of ammonium, while <44% of CFX removal was observed in the absence of ammonium, suggesting the cometabolic degradation of CFX by ammonia-oxidizing bacteria (AOB). After the addition of 50 μg/L CFX, the ammonia oxidizing rate (AOR) decreased from 36.6 to 11.0 mg N/(L·h·g VSS), followed by a slight recovery when CFX concentration decreased to below 8 μg/L. Ammonia monooxygenase (AMO) activity showed a similar trend with that of AOR. The quantitative reverse transcription PCR assay indicated that the expression level of amoA gene was significantly upregulated (up to 3-fold, p < 0.05) due to the addition of CFX, while decreased to the normal level once CFX was degraded, suggesting a mechanism of AOB to neutralize the toxicity of CFX by metabolizing ammonia more effectively. Meanwhile, the biotoxicity test showed the degradation products of CFX did not exhibit any antibacterial impacts in terms of cell viability, compared to the parent compounds. Our finding shed a light on AMO-mediated cometabolic biodegradation of antibiotics in nitrifying cultures. Unlabelled Image • CFX could be cometabolically degraded by enriched nitrifying sludge. • CFX affected ammonia oxidation rate and ammonia monooxygenase activity. • The expression level of amoA gene was upregulated during CFX degradation process. • The antibacterial effect of CFX was mitigated after degradation. [ABSTRACT FROM AUTHOR]

Abstract Heavy metals often coexist in contaminated wastewater systems and their competitive behavior could affect the adsorption capacity of biochar. Till now, the competitive adsorption of heavy metals by biochar derived from anaerobically digested sludge has never been reported. In this work, biochar from anaerobically digested sludge was synthesized and characterized to explore the competitive behavior of widely co-existed Pb(II) and Cd(II). The mutual effects and inner mechanisms of their adsorption on studied biochar were systematically investigated via single-metal and binary-metals systems. In single-metal system, the biochar exhibited much higher adsorption capacity for Pb(II) compared to that for Cd(II). The maximum adsorption capacities of Pb(II) and Cd(II) based on single-component adsorption isotherm were 0.75 and 0.55 mmoL/g, respectively, which were much higher than those reported biochars from different materials. In binary-metals system, the Cd(II) adsorption on biochar was severely inhibited, while the uptake of Pb(II) was not affected significantly. The results of binary-components adsorption isotherm clearly demonstrated the competitive adsorption between two metals occurred as well as the preference of biochar for Pb(II) compared to Cd(II). FTIR and metal characteristics analysis results revealed that Pb(II) had exactly the same adsorption sites with Cd(II), but Pb(II) has a greater affinity than Cd(II), thereby exhibiting a competitive advantage in the coexisting system. Graphical abstract Image 1 Highlights • Biochar of anaerobically digested sludge demonstrated great adsorption capacities. • High interference between two metals was observed in the coexisting system. • Binary-components competitive adsorption isotherm described competitive behavior. • The adsorption sites of Pb(II) entirely overlapped with those of Cd(II). • Pb(II) has a greater affinity for studied biochar than Cd(II). [ABSTRACT FROM AUTHOR]

Plant secondary metabolites (PSMs) are bioactive compounds with dual benefits for plants and humans. The correlation between PSMs and the endomembrane system (ES) is an adaptive strategy that has been neglected due to the complexity of the model angiosperm plant system. Bryophytes, especially liverworts, usually have simple single-layer cellular structures and a unique PSM-related organelle, known as the oil body (OB; synapomorphy to liverwort), suggesting them as a powerful model plant. Recent studies in Marchantia polymorpha revealed that the redirection of the secretory pathway along with several key transcription factors contribute to the formation of OBs in liverworts. Studying the organelle biogenesis in bryophytes can reveal the correlation between PSMs and the ES, and provide useful information for synthetic biology of bryophytes for pharmaceutical purposes. New organelle acquisition through neofunctionalization of the endomembrane system (ES) with respect to plant secondary metabolism is a key evolutionary strategy for plant adaptation, which is overlooked due to the complexity of angiosperms. Bryophytes produce a broad range of plant secondary metabolites (PSMs), and their simple cellular structures, including unique organelles, such as oil bodies (OBs), highlight them as suitable model to investigate the contribution of the ES to PSMs. In this opinion, we review latest findings on the contribution of the ES to PSM biosynthesis, with a specific focus on OBs, and propose that the ES provides organelles and trafficking routes for PSM biosynthesis, transportation, and storage. Therefore, future research on ES-derived organelles and trafficking routes will provide essential knowledge for synthetic applications. [ABSTRACT FROM AUTHOR]

Abstract: The photosystem II (PSII) in green plants exhibits marvelous oxygen production in neutral environments. However, artificially developed oxygen evolution catalysts (OECs) show much less activity, and the oxygen evolution reaction (OER) is now becoming a bottleneck in many energy‐related issues. Here, the PSII is mimicked to design an efficient OER system in neutral environments by introducing an oleylamine (OAm) organic layer to cap the Co3O4 OEC, and employing buffers as proton shuttles in the system. Consequently, the activity is largely enhanced. The current density can reach 10 mA cm−2 at an overpotential (η) of 390 mV in the best case in neutral environment. The turnover frequency is 0.0117 at η of 400 mV, almost the same as that in 1 m KOH solutions. The surface chemistry of the Co3O4 OEC indicates that the OAm can promote the activity. The reason that buffers as proton shuttles can greatly facilitate the reaction is ascribed to the proton‐coupled electron transfer process in the OER mechanism. These results may stimulate new perspectives on mimicking natural systems as well as new insights in electrocatalysis. [ABSTRACT FROM AUTHOR]

Hypoxia in vivo induces oligozoospermia, azoospermia, and degeneration of the germinal epithelium, but the underlying molecular mechanism of this induction is not fully clarified. The aim of this study was to investigate the role of the death receptor pathway and the mitochondrial pathway in hypoxia-induced apoptosis of mouse GC-2spd (GC-2) cells and the relationship between HIF-1α and apoptosis of GC-2 cells induced by hypoxia. GC-2 cells were subjected to 1% oxygen for 48 hr. Apoptosis was detected by flow cytometry, TUNEL staining, LDH, caspase-3/8/9 in the absence and presence of HIF-1α siRNA. The protein levels of apoptosis-related markers were determined by Western blot in the presence and absence of HIF-1α siRNA. Mitochondrial transmembrane potential change was observed by in situ JC-1 staining. Cell viability was assessed upon treatment of caspase-8 and 9 inhibitors. The results indicated that hypoxia at 1% oxygen for 48 hr induced apoptosis of GC-2 cells. A prolonged exposure of GC-2 cells to hypoxic conditions caused downregulation of c-FLIP, DcR2 and Bcl-2 and upregulation of DR5, TRAIL, Fas, p53, and Bax, with an overproduction of caspase-3/8/9. Moreover, hypoxia at this level had an effect on mitochondrial depolarization. In addition, specific inhibitors of caspase-8/9 partially suppressed hypoxia-induced GC-2 cell apoptosis, and the anti-apoptotic effects of the caspase inhibitors were additive. Of note, HIF-1α knockdown attenuated hypoxia and induced apoptosis of GC-2 cells. In conclusion, our data suggest that the death receptor pathway and mitochondrial pathway, which are likely mediated by HIF-1α, contribute to hypoxia-induced GC-2 cell apoptosis. [ABSTRACT FROM AUTHOR]

Reliable modelling of sulfide and methane production in sewer systems is required for efficient sewer emission management. Wastewater compositions affect sulfide and methane production kinetics through both its short-term variation influencing the substrate availability to sewer biofilms, and its long-term variation affecting the sewer biofilm structure. While the short-term effect is well considered in existing sewer models with the use of Monod or half-order equations, the long-term effect has not been explicitly considered in current sewer models suitable for network modelling. In this study, the long-term effect of wastewater compositions on sulfide and methane production activities in rising main sewers was investigated. A detailed biofilm model was firstly developed, and then calibrated and validated using experimental data measured during the entire biofilm development period of a laboratory sewer reactor. Based on scenario simulations using the detailed biofilm model, empirical equations describing the long-term effect of sulfate and sCOD (soluble chemical oxygen demand) concentrations on k H2S (the maximum sulfide production rate of sewer biofilm) and k CH4 (the maximum methane production rate of sewer biofilm) were proposed. These equations require further verification in future studies before their potential integration into network-wide sewer models. [ABSTRACT FROM AUTHOR]

A novel three-dimensional (3D) superstructure of cobalt hydroxide carbonate assembled from nanoneedles has been synthesized via a facile hydrothermal method. Furthermore, we tested the electrocatalytic oxygen evolution reaction performance, which demonstrated that the superstructure exhibited high catalytic activity, achieving 10 mA cm−2 at a low overpotential of merely 240 mV. [ABSTRACT FROM AUTHOR]

Activated sludge contains highly complex microbial communities, which play crucial roles in pollutant removal performance in wastewater treatment plants (WWTPs). Metagenomic sequencing was applied to characterize microbial community and functional profiles within activated sludge from a full-scale municipal WWTP carrying out simultaneous nitrogen and phosphorous removal (SNPR). We applied the assembled contigs (N90 of 591 bp) and predicted genes to conduct taxonomic and function annotations, respectively. Results revealed the extraordinary microbial diversity of activated sludge, which included detection of minority populations that are difficult to be explored by traditional molecular methods. Taxonomic analysis indicated that the dominant bacterial phyla were Proteobacteria , Nitrospirae , Bacteroidetes , Actinobacteria and Firmicutes . The abundance of the key organisms involved in nitrogen and phosphorous removal were qualified. Aerobic ammonia-oxidizing bacteria distinctly dominate over ammonia-oxidizing archaea and anaerobic ammonium oxidation bacteria. Various key enzymes involved in the global nitrogen cycle were annotated in the activated sludge. High abundance of the known polyphosphate accumulating organisms was detected (approximately 4.89% of the overall population reads), supporting good phosphorous removal performance. This study provides a comprehensive insight into the community structure and diversity of the SNPR system, and will provide foundation for optimal operation of nutrient removal systems. [ABSTRACT FROM AUTHOR]

The main challenges to the direct methanol fuel cells are the activity and durability of electrocatalysts. To alleviate such issues, a recently proposed strategy introduces an exotic element to form Pt-based alloy nanostructures. This study reports a green route to prepare porous flowerlike Pt72Ru28 nanoalloys assembled with sub-4.0 nm particles. The peak current density and mass activity on these as-synthesized porous flowerlike Pt72Ru28 nanoalloys can be increased to 10.98 mA cm−2 and 1.70 A mg−1 Pt for methanol oxidation in acidic medium. They are respectively 4.19/3.54, 4.27/5.0, and 5.74/1.73 times those on the commercial Pt black, Pt50Ru50 black, and Ru50Pt50/C. These porous flowerlike Pt72Ru28 nanoalloys have a much higher long-term durability than commercial Pt black, Pt50Ru50 black, and Ru50Pt50/C. More significantly, the porous Pt72Ru28 bimetallic nanoalloys have long-term solvent durability after immersion in water for 16 months. The peak current density and mass activity on porous Pt72Ru28 nanoalloys are still 7.76 mA cm−2 and 1.2 A mg−1 Pt. These experimental results show an effective approach to the development of PtRu nanoalloys as electrocatalysts with substantially enhanced activity and durability for direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Biological conversion of gaseous compounds (e.g., H 2 /CO 2 ) into valuable liquid fuels or chemicals using mixed culture is a promising technology, which could be effectively and efficiently implemented in a membrane biofilm reactor (MBfR) with gas being supplied from inside of membranes. In this study, a model integrating multiple production pathways of fatty acids (including acetate, butyrate, and caproate) was developed and tested using reported mixed culture experimental data from a lab-scale MBfR fed with 60% H 2 and 40% CO 2 . The uncertainty of the four estimated model parameters was explored by a sensitivity analysis. With the developed model, the impacts of key process parameters (i.e., gas supply and hydraulic retention time (HRT)) on the performance of the MBfR converting H 2 /CO 2 to fatty acids were then investigated. The results show that a high HRT is imperative for chain elongation to produce a higher proportion of caproate with a higher added value. A proper gas supply should be provided to favour the speciation of biological gas conversion products as well as to fully exploit the conversion capacity of the MBfR. The findings of this work provide useful information for a better understanding and further applications of this MBfR technology for mixed culture syngas fermentation. [ABSTRACT FROM AUTHOR]

Nitrate (NO 3 − ) and arsenite (As(III)) are two major contaminants in groundwater, which could cause significant risks to human wellbeing and ecological system. In this work, a single-stage membrane biofilm reactor (MBfR) coupling denitrifying anaerobic methane (CH 4 ) oxidation (DAMO) and autotrophic As(III) oxidation processes was proposed for the first time to achieve the in-situ or ex-situ simultaneous removal of NO 3 − and As(III) from groundwater. CH 4 is supplied to the MBfR through gas-permeable membranes while NO 3 − and As(III) are provided in the bulk liquid. A mathematical model was developed by integrating the well-established biokinetics of DAMO microorganisms with the kinetics of As(III)-oxidizing bacteria (AsOB). The key parameter values of AsOB were specifically estimated using the batch experimental data of an enriched pure AsOB culture in conjunction with thermodynamic state calculations. The maximum specific growth rate of AsOB ( μ AsOB ) and the yield coefficient for AsOB ( Y AsOB ) were determined to be 0.00161 h −1 and 0.016 g COD g −1 As, respectively. The modeling results demonstrated that both influent surface loading (or hydraulic retention time (HRT)) and CH 4 surface loading played important roles in controlling the steady-state microbial community structure and thus significantly affected the system performance. The As(III)/NO 3 − ratio between 0.1 and 2 g As g −1 NO 3 − -N in the influent would have no significant impact on the overall system performance despite the varying microbial composition in the biofilm. Through properly adjusting the influent surface loading (or HRT) and CH 4 surface loading whilst maintaining a sufficient biofilm thickness at a suitable influent As(III)/NO 3 − ratio, the maximum removal efficiencies of total nitrogen and As(III) could both reach above 95.0%, accompanied by a high CH 4 utilization efficiency of up to 99.0%. [ABSTRACT FROM AUTHOR]

Biological nitrogen removal by using a co-culture of Anammox bacteria, ammonia-oxidizing archaea (AOA) and (ammonia-oxidizing bacteria) AOB microorganisms in a sequencing batch reactor (SBR) has previously been demonstrated experimentally. In this work, a mathematical model is developed to describe the microbial interaction among AOA, AOB and Anammox bacteria in the single-stage SBR and provide the first insights on the key role of AOA in such system. In this model, AOA and AOB jointly convert ammonium to nitrite partially, which provides electron acceptors to Anammox bacteria to oxidize the remaining ammonium forming dinitrogen gas. The model is successfully calibrated and validated using the long-term (around 350 days) dynamic experimental data from the SBR system, as well as two independent batch tests at different operational stages of the SBR. The model satisfactorily describes the nitrogen conversion data from the system. Modeling results show that AOA would outcompete AOB under low ammonium concentration and low dissolved oxygen conditions due to the revealed higher NH 4 + affinity ( K N H 4 A O A of 0.06 g N m −3 ) and thus higher ammonia oxidation rate under oxygen-limited conditions, indicating that AOA could be a better partner to Anammox bacteria compared to AOB when treating low strength nitrogen sewage. The developed model could also predict and distinguish the different contributions of AOA and AOB to overall aerobic ammonia oxidizing potential, with more than 50% of ammonia oxidation being mediated by AOB at initial stage (~300 days) and AOA being responsible for up to 90% of the ammonium removal afterwards. The results suggest AOA coupled with Anammox could provide new possibilities for biological nitrogen removal from low strength ammonium wastewater. [ABSTRACT FROM AUTHOR]

• The symmetry-based kinematic theory well explains the shape evolutions. • Seeds don't play the most essential role in the seed-mediated growth. • The growth habit that depends on the conditions plays the most essential role. • The nanoparticle symmetry can be manipulated by the growth habit. Seed-mediated growth methods have been widely adopted to fabricate nanoparticles (NPs) with uniform shapes and narrow size distributions. Here we systematically investigate the role of seeds to the final morphologies by studying the shape evolution of mini Au nanorods (NRs, 11.6 nm in length and 3.7 nm in width) in different growth environments from the perspective of the symmetry-based kinematic theory (SBKT). The SBKT emphasizes more the crystal growth processes than the thermodynamic stability of the final structures. According to the SBKT, it is the growth habit of the growing nanoparticles depending on the reaction systems, but not the seeds themselves, that dominates the shape evolution. The growth habits mainly include the preferential growth directions (PGDs) and the properties of the kinematic waves. The results overall supported that (1) if the growth habit was not significantly changed, the NP symmetry could be maintained and the monodispersity of the final products would increase; (2) if the growth habit has changed a lot, the NR symmetry could be maintained under conditions with significant coherent growth; (3) otherwise, the NR symmetry would be repaired to that of the lattice. [ABSTRACT FROM AUTHOR]

• MPs' specific surface area increased while relative crystallinity decreased after HTP. • Poor thermal stability groups of MPs were converted to ketone or carboxyl groups. • HTP resulted in blocking the adsorption of a variety of MPs for pollutants. • HTP enhanced the inhibitory effect of MPs on AD by accelerating TOC release. • Leachate of MPs reduced the abundance of vital anaerobes. Waste activated sludge (WAS) contains high concentrations of microplastics (MPs), which could serve as vectors of various organic pollutants and heavy metals, causing synergistic transportation and pollution. The application of combined hydrothermal pretreatment (HTP) and anaerobic digestion (AD) has raised growing concerns since the low-temperature hydrothermal treatment could enhance the biogas production of WAS. However, the changes in physicochemical properties, adsorption performances, and effects on AD of MPs by HTP have not been studied. The study used three typical MPs in WAS, and it was found that the HTP (170°C & 30min) increased MPs' specific surface area and carbonyl index (CI) while decreasing the relative crystallinity. The adsorption capacity to Cd increased through the carbonylation for polyethylene microplastic (PE-MP) and polystyrene microplastic (PS-MP) while decreasing by the dechlorination for polyvinyl chloride microplastic (PVC-MP). Meanwhile, increased hydrophilicity reduced the adsorption capacities of all three typical MPs for ofloxacin. The above results indicated that the HTP could be worth blocking the adsorption of polar MPs for polar pollutants. For the pristine MPs, only PVC-MP at the highest concentration (0.5 g kg−1 VS) significantly (p < 0.05) reduced methane production by 16.2 ± 3.3% of WAS without the HTP. However, the HTP resulted in significant (p < 0.05) inhibition of methane production of WAS at high concentrations of PE-MP and PVC-MP (e.g., 0.1 and 0.5 g kg−1 VS), which was due to the acceleration of the released toxic plastic additives (dibutyl phthalate, dimethyl phthalate, and bisphenol-A). Microbial analysis showed the abundances of vital anaerobes, such as acid-producing bacteria (Acetoanerrobium and Mesotoga), proteolytic bacteria (Proteiniborus), and methanogens (Methanosaeta) clearly decreased with the PE-MP and PVC-MP after the HTP, which might result in the decreased methane production. The study provided deep-insight of MPs' behaviors during the combined HTP-AD process. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Dorsal root entry zone (DREZ) lesioning is a classical and effective treatment for brachial plexus avulsion (BPA). However, because of a limited number of cases reported in the literature, the factors affecting surgical outcomes are not known. Furthermore, whether this ablative procedure in the spinal level can change the status of phantom limb pain (PLP) and phantom limb sensation (PLS) is unknown. We retrospectively reviewed the patients with preganglionic BPA who underwent DREZ lesioning at a single center. Patients' baseline characteristics and long-term pain and complications were collected. Postoperative changes in PLP and PLS were recorded. Kaplan-Meier analysis was used to evaluate pain-free survival. Multivariate Cox regression analysis was performed to identify factors affecting pain outcomes. A total of 112 patients met the study inclusion criteria. With an average (range) follow-up of 47.4 (10-134) months, the long-term effectiveness and complication rate were 82.1% and 25.9%, respectively. Of 37 patients (33.0%) who developed PLS, 67.6% (25/37) experienced pain relief, whereas in 45.9% (17/37), PLS disappeared or changed after DREZ lesioning. Multivariate analysis showed that patients with shorter pain duration (≤5 years) and PLS had worse pain outcomes. This study revealed factors that predict the pain outcome of DREZ lesioning based on a large series of cases. The diverse postoperative changes in phantom limb indicate that the mechanisms underlying PLS and PLP at the spinal or supraspinal level may vary among patients with BPA. Future studies should investigate the contribution of maladaptive brain plasticity to the outcomes of patients undergoing DREZ lesioning. [ABSTRACT FROM AUTHOR]

Several mathematical models have been proposed to describe nitrous oxide (N 2 O) production by ammonia oxidizing bacteria (AOB) under varying operational conditions. However, none of these N 2 O models are able to capture N 2 O dynamics caused by the variation of inorganic carbon (IC) concentration, which has recently been demonstrated to be a significant factor influencing N 2 O production by AOB. In this work, a mathematical model that describes the effect of IC on N 2 O production by AOB is developed and experimentally validated. The IC effect is considered by explicitly including the AOB anabolic process in the model, which is coupled to the catabolic process with the use of the Adenosine triphosphate (ATP) and Adenosine diphosphate (ADP) pools. The calibration and validation of the model were conducted using experimental data obtained with two independent cultures, including a full nitrification culture and a partial nitritation culture. The model satisfactorily describes the N 2 O data from both systems at varying IC concentrations. This new model enhances our ability to predict N 2 O production by AOB in wastewater treatment systems under varying IC conditions. [ABSTRACT FROM AUTHOR]

Soluble microbial products (SMP) formed by microorganisms in wastewater treatment plants (WWTPs) adversely affect final effluent quality and treatment efficiency. It is difficult to distinguish SMP from residual proteins, lipids and carbohydrates present in the influent that may persist during treatment. No method is currently available to determine quantitatively the extent to which SMP contribute to organic discharges from municipal WWTPs. In this work a modeling approach is presented which allows the SMP fraction of the effluent of a municipal WWTP to be quantified and described. The model is validated, in terms of utilization-associated products, biomass-associated products and extracellular polymeric substances, using influent from a municipal WWTP. SMP was found to account for, on average, 27 mg/L of chemical oxygen demand (COD), or 61% of the total COD in the WWTP effluent. Over 90% of the SMP was comprised of biomass-associated products. Five main factors influencing SMP formation in WWTP were evaluated. Neither wastewater composition nor mixed liquor suspended solids concentration was found to affect SMP production. On the other hand, a positive correlation was observed for SMP formation with both solids retention time and influent COD concentration, and a negative correlation with hydraulic retention time. Thus, operating or designing WWTPs with short solids retention and long hydraulic retention times could be considered as solutions for minimizing SMP production. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N 2 O) can be emitted from wastewater treatment contributing to its greenhouse gas footprint significantly. Mathematical modeling of N 2 O emissions is of great importance toward the understanding and reduction of the environmental impact of wastewater treatment systems. This article reviews the current status of the modeling of N 2 O emissions from wastewater treatment. The existing mathematical models describing all the known microbial pathways for N 2 O production are reviewed and discussed. These included N 2 O production by ammonia-oxidizing bacteria (AOB) through the hydroxylamine oxidation pathway and the AOB denitrification pathway, N 2 O production by heterotrophic denitrifiers through the denitrification pathway, and the integration of these pathways in single N 2 O models. The calibration and validation of these models using lab-scale and full-scale experimental data is also reviewed. We conclude that the mathematical modeling of N 2 O production, while is still being enhanced supported by new knowledge development, has reached a maturity that facilitates the estimation of site-specific N 2 O emissions and the development of mitigation strategies for a wastewater treatment plant taking into the specific design and operational conditions of the plant. [ABSTRACT FROM AUTHOR]

Mathematical models for nitrous oxide (N 2 O) production by ammonia oxidizing bacteria (AOB) based on a single pathway have been proposed to support the design and operation of wastewater treatment plants (WWTPs). However, the boundary conditions for each of these models have not been established to date. This study tests the predictive ability of two single-pathway models based on the AOB denitrification pathway and the hydroxylamine (NH 2 OH) oxidation pathway, respectively, to describe the N 2 O data generated by a N 2 O model that incorporates both pathways, and provides theoretical guidance on how to use these two single-pathway models as well as the two-pathway model under various conditions. The model based on the AOB denitrification pathway can be used under the condition of a constant dissolved oxygen (DO) concentration, applied either at a low DO concentration (<∼0.5 mg O 2 /L) with any non-inhibitory nitrite (NO 2 − ) concentrations or at higher DO (⩾∼0.5 mg O 2 /L) with relatively high NO 2 − (⩾∼1.0 mg N/L) but non-inhibitory concentrations. The model based on the NH 2 OH oxidation pathway can be applied under the condition of relatively high DO concentrations (⩾∼1.5 mg O 2 /L), being either constant or time-varying, with any non-inhibitory NO 2 − concentrations. Under other conditions, the two-pathway model should be applied. [ABSTRACT FROM AUTHOR]

Post growth of particles will lead to new nanostructure formation, and blur the boundaries of crystal growth and molecular chemistry as well. The driving force of post growth usually stems from the inherent stabilities of the nanoparticles (NPs) and the environmental changes, which results in the transformation of the pristine nanostructures. One type of post growth driven by thermodynamic stability is Ostwald ripening, which usually leads to the elimination of small particles, and can be utilized to prepare hollow structures. By sophisticatedly controlling the reaction conditions, the NPs may undergo oriented attachment to form nanostructures with more complexity. This process is different from the random aggregation of nanoparticles; the final morphologies can be ingeniously controlled, and the kinetics resemble polymerization in some cases. If the chemical bonding during the oriented attachment process is replaced by non-covalent bonding, self-assembly of the NPs is achieved. Self-assembly of NPs further extends the diversity of nanostructures, as well as the understanding of crystallization. Post growth of particles is also a feasible strategy to fabricate heterostructures. The wetting behaviour sheds light on the final morphologies of the heterostructures. Meanwhile, seed mediated growth enables an alternative method to control pre-formed NPs. Another heterostructure of atomically-thin layered sheets connected via van der Waals forces also extends the potential of nanomaterials. The driving forces of the post growth of particles are divergent, and the applications are various. It can be utilized to prepare homogeneous and heterogeneous structures. [ABSTRACT FROM AUTHOR]

Recent studies have shown that sewer systems produce and emit a significant amount of methane. Methanogens produce methane under anaerobic conditions in sewer biofilms and sediments, and the stratification of methanogens and sulfate-reducing bacteria may explain the simultaneous production of methane and sulfide in sewers. No significant methane sinks or methanotrophic activities have been identified in sewers to date. Therefore, most of the methane would be emitted at the interface between sewage and atmosphere in gravity sewers, pumping stations, and inlets of wastewater treatment plants, although oxidation of methane in the aeration basin of a wastewater treatment plant has been reported recently. Online measurements have also revealed highly dynamic temporal and spatial variations in methane production caused by factors such as hydraulic retention time, area-to-volume ratio, temperature, and concentration of organic matter in sewage. Both mechanistic and empirical models have been proposed to predict methane production in sewers. Due to the sensitivity of methanogens to environmental conditions, most of the chemicals effective in controlling sulfide in sewers also suppress or diminish methane production. In this paper, we review the recent studies on methane emission from sewers, including the production mechanisms, quantification, modeling, and mitigation. [ABSTRACT FROM AUTHOR]

The incidence of glossopharyngeal neuralgia is much lower than trigeminal neuralgia, there is relatively higher misdiagnosis rate for the disease, and the advantages and disadvantages of various treatment methods are worth discussing. This article is part of the Topical Collection on Functional Neurosurgery - Pain Dear Editor and Colleagues: Thank you very much for your attention and valuable comments on our previous article entitled "Reoperation after failed microvascular decompression for glossopharyngeal neuralgia". In a recent survey of 87 patients with glossopharyngeal neuralgia in our department, we have found that although VGR resulted in lower postoperative quality of life due to a high complication rate, most of these complications were mild. [Extracted from the article]

Edges are special sites in nanomaterials. The atoms residing on the edges have different environments compared to those in other parts of a nanomaterial and, therefore, they may have different properties. Here, recent progress in nanomaterial fields is summarized from the viewpoint of the edges. Typically, edge sites in MoS2 or metals, other than surface atoms, can perform as active centers for catalytic reactions, so the method to enhance performance lies in the optimization of the edge structures. The edges of multicomponent interfaces present even more possibilities to enhance the activities of nanomaterials. Nanoframes and ultrathin nanowires have similarities to conventional edges of nanoparticles, the application of which as catalysts can help to reduce the use of costly materials. Looking beyond this, the edge structures of graphene are also essential for their properties. In short, the edge structure can influence many properties of materials. [ABSTRACT FROM AUTHOR]

The effect of inorganic carbon (IC) on nitrous oxide (N 2 O) production by ammonia oxidizing bacteria (AOB) was investigated over a concentration range of 0–12 mmol C/L, encompassing typical IC levels in a wastewater treatment reactors. The AOB culture was enriched along with nitrite-oxidizing bacteria (NOB) in a sequencing batch reactor (SBR) to perform complete nitrification. Batch experiments were conducted with continuous carbon dioxide (CO 2 ) stripping or at controlled IC concentrations. The results revealed a linear relationship between N 2 O production rate (N 2 OR) and IC concentration ( R 2 = 0.97) within the IC range studied, suggesting a substantial effect of IC on N 2 O production by AOB. Similar results were also obtained with an AOB culture treating anaerobic sludge digestion liquor. The fundamental mechanism responsible for this dependency is unclear; however, in agreement with previous studies, it was observed that the ammonia oxidation rate (AOR) was also influenced by the IC concentration, which could be well described by the Monod kinetics. These resulted in an exponential relationship between N 2 OR and AOR, as previously observed in experiments where AOR was altered by varying dissolved oxygen and ammonia concentrations. It is therefore possible that IC indirectly affected N 2 OR by causing a change in AOR. The observation in this study indicates that alkalinity (mostly contributed by IC) could be a significant factor influencing N 2 O production and should be taken into consideration in estimating and mitigating N 2 O emissions in wastewater treatment systems. [ABSTRACT FROM AUTHOR]

Both nitrite ( NO 2 − ) and dissolved oxygen (DO) play important roles in nitrous oxide (N 2 O) production by ammonia oxidizing bacteria (AOB). However, few studies focused on the combined effect of them on N 2 O production by AOB as well as the corresponding mechanisms. In this study, N 2 O production by an enriched nitrifying sludge, consisting of both AOB and nitrite-oxidizing bacteria (NOB), was investigated under various NO 2 − and DO concentrations. At each investigated DO level, both the biomass specific N 2 O production rate and the N 2 O emission factor (the ratio between N 2 O nitrogen emitted and the ammonium nitrogen converted) increased as NO 2 − concentration increased from 3 mg N/L to 50 mg N/L. However, at each investigated NO 2 − level, the maximum biomass specific N 2 O production rate occurred at DO of 0.85 mg O 2 /L, while the N 2 O emission factor decreased as DO increased from 0.35 to 3.5 mg O 2 /L. The analysis of the process data using a mathematical N 2 O model incorporating both the AOB denitrification and hydroxylamine (NH 2 OH) oxidation pathways indicated that the contribution of AOB denitrification pathway increased as NO 2 − concentration increased, but decreased as DO concentration increased, accompanied by a corresponding change in the contribution of NH 2 OH oxidation pathway to N 2 O production. The AOB denitrification pathway was predominant in most cases, with the NH 2 OH oxidation pathway making a comparable contribution only at high DO level (e.g. 3.5 mg O 2 /L). [ABSTRACT FROM AUTHOR]

Biological wastewater treatment processes usually occur under dynamic conditions involving a dynamic regime with respect to carbon substrate, which results in different microbial internal storage processes. These storage processes play important roles in pollutant removal (e.g., chemical oxygen demand, nitrogen and phosphate removal) and resource recovery (e.g., anaerobic digestion for methane production). This review focuses on two different internal storage processes: microbial storage for shock loading of electron donor and another for separate electron donor and acceptor. The review gives the up-to-date status on several essential microbial internal storage issues: their formation and consumption, the kinetics of these processes, the key factors governing microbial storage, their relationship to microbial growth and other important microbial products, their role in nitrous oxides emissions, and their implications in biological wastewater treatment systems. Although previous research in microbial internal storage has undoubtedly improved our level of understanding, it is clear that much remains to be learned about the processes, as many unanswered questions still remain; some of these important future research areas are then outlined. One of the challenges appears to be the competitions for carbon substrate by these microbial internal storage groups when they encounter the same dynamic regimes. [ABSTRACT FROM PUBLISHER]

Recent studies have demonstrated significant sulfide and methane production by sewer biofilms, particularly in rising mains. Sewer sediments in gravity sewers are also biologically active; however, their contribution to biological transformations in sewers is poorly understood at present. In this study, sediments collected from a gravity sewer were cultivated in a laboratory reactor fed with real wastewater for more than one year to obtain intact sediments. Batch test results show significant sulfide production with an average rate of 9.20 ± 0.39 g S/m 2 ·d from the sediments, which is significantly higher than the areal rate of sewer biofilms. In contrast, the average methane production rate is 1.56 ± 0.14 g CH 4 /m 2 ·d at 20 °C, which is comparable to the areal rate of sewer biofilms. These results clearly show that the contributions of sewer sediments to sulfide and methane production cannot be ignored when evaluating sewer emissions. Microsensor and pore water measurements of sulfide, sulfate and methane in the sediments, microbial profiling along the depth of the sediments and mathematical modelling reveal that sulfide production takes place near the sediment surface due to the limited penetration of sulfate. In comparison, methane production occurs in a much deeper zone below the surface likely due to the better penetration of soluble organic carbon. Modelling results illustrate the dependency of sulfide and methane productions on the bulk sulfate and soluble organic carbon concentrations can be well described with half-order kinetics. [ABSTRACT FROM AUTHOR]

Full-scale application of partial nitritation and anammox in a single floc-based sequencing batch reactor (SBR) has been achieved for high-rate nitrogen (N) removal, but mechanisms resulting in reliable operation are not well understood. In this work, a mathematical model was calibrated and validated to evaluate operating conditions that lead to out-competition of nitrite oxidizers (NOB) from the SBRs and allow to maintain high anammox activity during long-term operation. The validity of the model was tested using experimental data from two independent previously reported floc-based full-scale SBRs for N-removal via partial nitritation and anammox, with different aeration strategies at aeration phase (continuous vs. intermittent aeration). The model described the SBR cycle profiles and long-term dynamic data from the two SBR plants sufficiently and provided insights into the dynamics of microbial population fractions and N-removal performance. Ammonium oxidation and anammox reaction could occur simultaneously at DO range of 0.15–0.3 mg O 2 L −1 at aeration phase under continuous aeration condition, allowing simplified process control compared to intermittent aeration. The oxygen supply beyond prompt depletion by ammonium oxidizers (AOB) would lead to the growth of NOB competing with anammox for nitrite. NOB could also be washed out of the system and high anammox fractions could be maintained by controlling sludge age higher than 40 days and DO at around 0.2 mg O 2 L −1 . Furthermore, the results suggest that N-removal in SBR occurs via both alternating nitritation/anammox and simultaneous nitritation/anammox, supporting an alternative strategy to improve N-removal in this promising treatment process, i.e., different anaerobic phases can be implemented in the SBR-cycle configuration. [ABSTRACT FROM AUTHOR]

Dissolved oxygen (DO) is commonly recognized as an important factor influencing nitrous oxide (N 2 O) production by ammonia-oxidizing bacteria (AOB). However, it has been difficult to separate the true effect of DO from that of nitrite, as DO variation often affects nitrite accumulation. The effect of DO on N 2 O production by an enriched nitrifying sludge, consisting of both AOB and nitrite-oxidizing bacteria (NOB), was investigated in this study. Nitrite accumulation was minimised by augmenting nitrite oxidation through the addition of an enriched NOB sludge. It was demonstrated that the specific N 2 O production rate increased from 0 to 1.9 ± 0.09 ( n = 3) mg N 2 O–N/hr/g VSS with an increase of DO concentration from 0 to 3.0 mg O 2 /L, whereas N 2 O emission factor (the ratio between N 2 O nitrogen emitted and the ammonium nitrogen converted) decreased from 10.6 ± 1.7% ( n = 3) at DO = 0.2 mg O 2 /L to 2.4 ± 0.1% ( n = 3) at DO = 3.0 mg O 2 /L. The site preference measurements indicated that both the AOB denitrification and hydroxylamine (NH 2 OH) oxidation pathways contributed to N 2 O production, and DO had an important effect on the relative contributions of the two pathways. This finding is supported by analysis of the process data using an N 2 O model describing both pathways. As DO increased from 0.2 to 3.0 mg O 2 /L, the contribution of AOB denitrification decreased from 92% − 95%–66% − 73%, accompanied by a corresponding increase in the contribution by the NH 2 OH oxidation pathway. [ABSTRACT FROM AUTHOR]

CD4+ FOXP3+ regulatory T (Treg) cells constitute a heterogeneous and plastic T-cell lineage that plays a pivotal role in maintaining immune homeostasis and immune tolerance. However, the fate of human Treg cells after loss of FOXP3 expression and the epigenetic mechanisms contributing to such a phenotype switch remain to be fully elucidated. In the current study, we demonstrate that human CD4+ CD25high CD127low/- Treg cells convert to two subpopulations with distinctive FOXP3+ and FOXP3- phenotypes following in vitro culture with anti-CD3/CD28 and interleukin-2. Digital gene expression analysis showed that upon in vitro expansion, human Treg cells down-regulated Treg cell signature genes, such as FOXP3, CTLA4, ICOS, IKZF2 and LRRC32, but up-regulated a set of T helper lineage-associated genes, especially T helper type 2 (Th2)-associated, such as GATA3, GFI1 and IL13. Subsequent chromatin immunoprecipitation-sequencing of these subpopulations yielded genome-wide maps of their H3K4me3 and H3K27me3 profiles. Surprisingly, reprogramming of Treg cells was associated with differential histone modifications, as evidenced by decreased abundance of permissive H3K4me3 within the downregulated Treg cell signature genes, such as FOXP3, CTLA4 and LRRC32 loci, and increased abundance of H3K4me3 within the Th2-associated genes, such as IL4 and IL5; however, the H3K27me3 modification profile was not significantly different between the two subpopulations. In conclusion, this study revealed that loss of FOXP3 expression from human Treg cells during in vitro expansion can induce reprogramming to a T helper cell phenotype with a gene expression signature dominated by Th2 lineageassociated genes, and that this cell type conversion may be mediated by histone methylation events. [ABSTRACT FROM AUTHOR]

Abstract: The quantification of nitrous oxide (N2O) emissions from open-surface wastewater treatment systems with surface aerators is difficult as emissions from the surface aerator zone cannot be easily captured by floating hoods. In this study, we propose and demonstrate a novel methodology to estimate N2O emissions from such systems through determination of the N2O transfer coefficient (k L a) induced by surface aerators based on oxygen balance for the entire system. The methodology is demonstrated through its application to a full-scale open oxidation ditch wastewater treatment plant with surface aerators. The estimated k L a profile based on a month-long measurement campaign for oxygen balance, intensive monitoring of dissolved N2O profiles along the oxidation ditch over a period of four days, together with mathematical modelling, enabled to determine the N2O emission factor from this treatment plant (0.52 ± 0.16%). Majority of the N2O emission was found to occur in the surface aerator zone, which would be missed if the gas hood method was applied alone. [Copyright &y& Elsevier]

Abstract: A multispecies one-dimensional biofilm model considering nitric oxide (NO) and nitrous oxide (N2O) productions for membrane aerated biofilm reactor (MABR) that remove nitrogen autotrophically through aerobic ammonia oxidation followed by Anammox is used to study the role of Anammox activity on the total nitrogen (TN) removal and the productions of NO and N2O. The model is applied to evaluate how periodic aeration as a control parameter reduces NO and N2O production but maintains high TN removal in MABR. The simulation results show over 3.5% of the removed TN could be attributed to NO and N2O production in MABR under the operational conditions optimal for TN removal (72%). An analysis of factors governing the Anammox activity in MABR shows that enhancing Anammox activity not only helps to achieve a high level of nitrogen removal but also reduces NO and N2O productions. Comparison of aeration strategies (periodic aeration vs. continuous aeration) reveals that periodic aeration can reduce NO and N2O production while maintaining a high level of nitrogen removal through promoting Anammox growth. Application of periodic aerations with different cycle frequencies to the MABR indicates that an increase in the cycle frequency of the periodic aeration can further maximize TN removal and minimize the NO and N2O production in membrane aerated biofilm. The information of this paper will be useful for understanding the indirect role of Anammox on NO and N2O productions and for optimizing the design and operation of MABR systems. [Copyright &y& Elsevier]

Abstract: Stent implantation is primarily used for the treatment of artery stenosis. However, the application and use of stent struts induces local and systemic inflammation, leading to intractable neointimal hyperplasia. CD4+ T cells are involved in artery stenosis diseases, but little is known about the influence of the CD4+ T cells on the inflammation reaction after stent implantation. In this study, we analyzed the frequency of signature transcription factors and proinflammatory cytokine expression from each subtype of CD4+ T cells in 50 patients receiving intracranial or cervical stent implantations from December 2011 to June 2012. The results showed that the frequency of signature transcription factor/cytokine production in Treg cells was reduced in the first week and returned to control levels at 3months after stent implantation. However, we observed opposite trends for Th17 cells, showing increased signature transcription factor/cytokine production during the acute phase, which returned to control levels after 3months. No significant difference in the frequency of signature transcription factor/cytokine expression was observed in Th1 cells from patients before and after stent implantation. We speculate that the maintenance of the frequency and function of Tregs controls the inflammatory response, which otherwise induces acute inflammation after stent implantation. [Copyright &y& Elsevier]

Highlights: [•] A novel HBc interacting protein, CD59, was identified in hepatocytes. [•] Down-regulation of CD59 makes hepatocytes sensible to complement mediated lysis. [•] CD59 down-regulation and MAC accumulation in HBV patients’ liver were observed. [•] Nuclear translocation of CD59 upon binding with HBc was experimentally detected. [•] CD59 down-regulation is probably driven through a negative feedback loop. [ABSTRACT FROM AUTHOR]

Abstract: Limited availability of carbon sources has been regarded as an important factor leading to N2O accumulation during denitrification in wastewater treatment. By varying the carbon (methanol) loading rate to a methanol utilizing denitrifying culture in the presence of various electron acceptors (nitrate, nitrite, N2O and their combinations), this study quantitatively investigated the electron distribution among different nitrogen oxide reductases during denitrification. The results showed that electron competition occurs under not only carbon limiting but also carbon abundant conditions. The electron distribution among the nitrogen oxide reductases is affected by the carbon loading rate, with a lower fraction of electrons distributed to the N2O reductase with reduced carbon loading rate. N2O accumulation occurs when the electron flux going to nitrite reduction is higher than that going to N2O reduction. The study also showed that, for the culture investigated, the carbon to nitrogen ratio is not a key factor leading to N2O accumulation. [Copyright &y& Elsevier]

Abstract: Soluble microbial products (SMP) are the major component of the residual organic fraction in biological wastewater treatment effluent. The impact of process parameters on SMP production by specific groups of bacteria is currently unknown. In this work, SMP production by activated sludge at different substrate concentrations, dissolved oxygen (DO) levels and temperatures, was evaluated by experimental and modeling approaches. The results showed that among the three parameters, SMP production was most sensitive to substrate concentration. Total SMP production was increased 70.5% by a threefold increase in substrate concentration, with SMP produced from heterotrophs, ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) increasing by 61.2%, 580.0% and 410.0%, respectively. The effect of temperature on SMP was less pronounced. Decreasing the temperature from 20 °C to 10 °C decreased total SMP by 17.2%, with SMP production from heterotrophs decreasing by 20.0%, and from the AOB and NOB increasing by 180.0% and 140.0%. DO concentration had nearly no effect on total and heterotrophic SMP production, while it did have a significant positive effect on autotrophic SMP production. SMP production from AOB and NOB decreased by 24.3% and 47.8%, respectively following a decrease in DO concentration from 8.7 to 1.5 mg/L. However, the net effect of DO on total SMP production was negligible. [Copyright &y& Elsevier]

Abstract: Oxygen limitation has been commonly recognized as an important factor causing nitric oxide (NO) and nitrous oxide (N2O) production. Due to the requirement of low oxygen conditions, membrane aerated autotrophic nitrogen removal biofilm systems that remove nitrogen through aerobic ammonia oxidation followed by Anammox may be prone to NO and N2O production. In this work, a mathematical model was constructed to assess the NO and N2O production potential in membrane aerated autotrophic biofilm under various operational conditions. The AOB-mediated denitrification pathway was used to model NO and N2O production. Simulations showed that a considerable amount of NO (0.2% of TN removed) and N2O (3.0% of TN removed) could be produced in membrane-aerated biofilm under operational conditions optimal for total nitrogen removal with 75% TN removal achieved. Both NO and N2O production is inherently related to TN removal in membrane aerated biofilm reactors (MABRs). NO and N2O production as well as total nitrogen removal depends on both the surface oxygen and ammonium loading rates. Biofilm thickness also has a significant effect on nitrogen removal and on NO and N2O production. An MABR would produce significantly less N2O in comparison to a conventional co-diffusional biofilm system under the same loadings of nitrogen and oxygen, due to the higher nitrite accumulation and outside distribution of AOB in the co-diffusional biofilm. Given the model structure is correct, high TN removal (>70%) with a relative low NO and N2O production (<1.0% of TN removed) in an MABR can be achieved by controlling the oxygen and ammonium surface loading at 2.0gm−2 day−1 and 1.0gm−2 day−1, respectively. These results provide useful support for the design and operation of MABRs. [Copyright &y& Elsevier]