Neglected sludge solid phase in sludge pretreatment process: Physicochemical characterization and mechanism study of its role in anaerobic degradation.

The low anaerobic digestion efficiency of the solid phase separated from pre-treated sludge indicates the need to explore other suitable resource utilization pathways for sludge solid phase. However, there is a lack of comprehensive and in-depth research on the physicochemical properties of sludge solid phase. This study comprehensively analyzes the characteristics of sludge solid phase and elucidates the mechanism of sludge solid phase in the anaerobic degradation of toxic wastewater. The results show that the surface free energy of sludge solid phase after different pre-treatments is mainly contributed by Lewis acid-base hydration free energy. The distribution of proteins on the surface of sludge solid phase plays a major role in the adhesion between sludge solid particles. Metal ions in the sludge solid phase are mainly present in the exchange state, followed by the carbonate state and the organics-bound state. The sludge solid phase obtained by sludge pH 12 + 150 °C treatment has the highest conductivity (1.36 mS/m) and capacitance (25.51 µF/g), mainly due to the presence of melanoidins in the sludge solid phase, which has similar semiquinone radicals to humic acids, thus increasing conductivity. The addition of sludge solid phase promotes an increase in cumulative methane production and rate of methane production. The sludge solid phase might play a role of an auxiliary carbon source acting as an adsorbent to buffer against toxicity inhibition and facilitate electron transfer. This study reveals the characteristics of sludge solid phase and its role in anaerobic digestion, providing theoretical guidance for finding suitable resource utilization pathways for sludge solid phase.

Novel bidentate N-coordinated alkylaluminum complexes: synthesis, characterization, and efficient catalysis for hydrophosphonylation.

Five new alkylaluminum complexes with different pyridinyl-substituted imines or cyclohexyl-substituted imines were synthesized and characterized successfully. The aluminum complex [FlCHNCH(CH3)Py]AlMe2(Py = 2-pyridyl) (1) was obtained by reacting 9-[2-pyridyl-CH(CH3)-NCH]Fl (Fl = fluorenyl) (L1) and equimolar AlMe3. The reactions of 9-(2-pyridyl-NCH)Fl (L2) and 9-[2-N(CH3)2-cyclohexyl-NCH]Fl (L3) with equimolar AlMe3 or AlEt3 afforded other alkylaluminum complexes [FlCHNPy]AlMe2(Py = 2-pyridyl) (2), [FlCHNPy]AlEt2 (Py = 2-pyridyl) (3), [FlCHNCyN(CH3)2]AlMe2 (Cy = 2-cyclohexyl) (4) and [FlCHNCyN(CH3)2]AlEt2 (Cy = 2-cyclohexyl) (5). All these complexes (1-5) were characterized using NMR spectroscopy, elemental analysis, and X-ray crystal structure analysis. The catalytic properties of these new alkylaluminum complexes for the hydrophosphonylation of aldimines were examined. Complex 5 showed the best catalytic performance under mild reaction conditions with a low catalyst loading (1 mol%), and 20 different substituents of aldimines were isolated with more than 90% yields.

Optimizing the Activation Energy of Reactive Intermediates on Single-Atom Electrocatalysts: Challenges and Opportunities.

Single-atom catalysts (SACs) have made great progress in recent years as potential catalysts for energy conversion and storage due to their unique properties, including maximum metal atoms utilization, high-quality activity, unique defined active sites, and sustained stability. Such advantages of single-atom catalysts significantly broaden their applications in various energy-conversion reactions. Given the extensive utilization of single-atom catalysts, methods and specific examples for improving the performance of single-atom catalysts in different reaction systems based on the Sabatier principle are highlighted and reactant binding energy volcano relationship curves are derived in non-homogeneous catalytic systems. The challenges and opportunities for single-atom catalysts in different reaction systems to improve their performance are also focused upon, including metal selection, coordination environments, and interaction with carriers. Finally, it is expected that this work may provide guidance for the design of high-performance single-atom catalysts in different reaction systems and thereby accelerate the rapid development of the targeted reaction.

Effects of the Carbon Support on Heterogeneous Molecular Catalysts for Carbon Dioxide Reduction.

Molecular catalysts stabilized on a support material, also called heterogeneous molecular catalysts, exhibit excellent performance in carbon dioxide reduction reaction (CO2 RR). Different support in these electrocatalysts can have a substantial influence on the activity, making support control one tool to enhance the CO2 RR performance. However, a systematic understanding of the support effects is lacking. Taking cobalt phthalocyanine (CoPc) immobilized onto different carbon materials as examples, we demonstrate that the surface area, pore structure and the morphology of the as-prepared heterogeneous molecular catalysts can influence the CO2 transfer and adsorption, and then change the CO2 RR activity. In contrast to the other four materials, CoPc/mesoporous carbon (MC) can efficiently convert carbon dioxide to carbon monoxide at minimal overpotential (-0.8 V vs. RHE) due to its special nanostructure and pore distribution. The results of this study suggest that the performance of electrocatalytic reduction of carbon dioxide can be improved by changing different substrates.

Exploration of browning reactions during alkaline thermal hydrolysis of sludge: Maillard reaction, caramelization and humic acid desorption.

The browning reaction produces melanoidins, 5-hydroxymethylfurfural (HMF) and humic acids which influence subsequent anaerobic digestion and protein recovery. This paper systematically evaluates the variation of organics that make sludge browning with heating temperature and reaction time, the effect of browning organics on protein recovery and anaerobic digestion, and finally proposes a pathway for the occurrence of the Maillard reaction (MR) in the sludge environment. The results show that the browning of sludge hydrolysate is related to the comprehensive influence of the MR, caramelization and humic acid desorption. The increase of temperature (80 °C-150 °C) and pH (9-13) will promote the extent of browning of sludge hydrolysate, and the sludge browning reaction basically stabilizes at the reaction time of 1 h. Humic acid and melanoidin could co-precipitate with the protein, thereby reducing the purity of the recovered protein. The inhibition of anaerobic digestion starts when the melanoidin concentration is 8.01 mmol/L. The three-dimensional fluorescence, GC-MS and FT-IR analysis show that melanoidins have the same functional groups and fluorescence properties as humic acid does, and the humic acid in the supernatant of the sludge treated with ATH was not only converted at its adsorbed state, but also possibly generated by the reaction of the dissolved proteins with polysaccharides. Finally, LC-MS/MS was used to identify the intermediate products of the MR and the possible structural formula of melanoidin. This study further clarifies the browning reaction in hydrothermal sludge treatment and provides help for the accuracy of subsequent studies.

Inhibition of Maillard reaction during alkaline thermal hydrolysis of sludge.

The Maillard reaction (MR) occurs during the alkaline thermal hydrolysis (ATH) of sludge, which affects the quantity and quality of recovered protein. In this paper, four different sulfites were added to investigate their inhibitory effects on melanoidin production. The results showed that sulfites inhibited melanoidin production during ATH of sludge and the inhibitory rate increased with their concentration. At a concentration of 5.71 g/L, the inhibitory rates of NaHSO3 on melanoidin were 63.27%. Furthermore, the 3D-EEM (Three-Dimension Excitation-Emission-Matrix) fluorescence spectroscopy and protein testing data showed that the inhibition of melanoidin production was accompanied by an increased protein concentration, and protein increased with increasing sulfites concentration. A 2.5-fold increase in protein concentration with Na2S2O4 significantly enhanced the quantity of protein recovered. Therefore, the addition of sulfite during ATH of sludge reduces the amount of non-biodegradable melanoidin, which in turn benefits protein recovery.

Environmental Regulation, Government Subsidies, and Green Technology Innovation-A Provincial Panel Data Analysis from China.

Economic development in the "new era" will require green innovation. To encourage the growth of green technology innovation, it has become fashionable to strengthen environmental regulation. However, the impact of environmental regulation on green technology innovation, as well as the role of government subsidies, needs to be examined. Utilizing fixed-effect models and 2SLS models to explore the impact of environmental regulation on green technology innovation in China from 2003 to 2017, this research sought to examine whether environmental regulations impact green technology innovation, as well as the role of government subsidies in the above-mentioned influence path. The findings support the Porter Hypothesis by demonstrating an inverted "U" relationship between environmental regulation and green technology innovation. The impact of environmental regulation on green technology innovation varies by region. To be specific, there is an inverted "U" relationship between environmental regulation and green technology innovation in China's central and central coast regions. In comparison, the north area, southern coast, and southwest region exhibit a "U" relationship between the two. The relationship is not significant in the Beijing-Tianjin region. Additionally, government subsidies act as an intermediate in this process, positively influencing firms to pursue green technology innovation during the earliest stages of environmental regulation strengthening. However, government subsidies above a certain level are unproductive and should be used appropriately and phased off in due course.

Biotransformation of RDX and HMX by Anaerobic Granular Sludge with Enriched Sulfate and Nitrate.

RDX and HMX are widely used energetic materials and they are recognized as environmental contaminants at numerous locations. The present study investigated the biotransformation of RDX and HMX by anaerobic granular sludge under sulfate- and nitrate-enriched conditions. The results showed that RDX and HMX could be transformed by anaerobic granular sludge when nitrate was present. However, the biotransformation of RDX and HMX was negatively influenced, especially with high nitrate concentrations. Sulfate-enriched conditions were more favorable for the removal of ammunition compounds by anaerobic granular sludge than nitrate-enriched conditions. The removal of RDX and HMX under both nitrate- and sulfate-enriched conditions was facilitated by the use of glucose as additional substrate. This knowledge may help identify factors required for rapid removal of RDX and HMX in high-rate bioreactors. These results can also be applied to devise an appropriate and practical biological treatment strategy for explosive contaminated wastewater.

The ultrastructural organization of actin and myosin II filaments in the contractile ring: new support for an old model of cytokinesis.

Despite recent advances in our understanding of the components and spatial regulation of the contractile ring (CR), the precise ultrastructure of actin and myosin II within the animal cell CR remains an unanswered question. We used superresolution light microscopy and platinum replica transmission electron microscopy (TEM) to determine the structural organization of actin and myosin II in isolated cortical cytoskeletons prepared from dividing sea urchin embryos. Three-dimensional structured illumination microscopy indicated that within the CR, actin and myosin II filaments were organized into tightly packed linear arrays oriented along the axis of constriction and restricted to a narrow zone within the furrow. In contrast, myosin II filaments in earlier stages of cytokinesis were organized into small, discrete, and regularly spaced clusters. TEM showed that actin within the CR formed a dense and anisotropic array of elongate, antiparallel filaments, whereas myosin II was organized into laterally associated, head-to-head filament chains highly reminiscent of mammalian cell stress fibers. Together these results not only support the canonical "purse-string" model for contractile ring constriction, but also suggest that the CR may be derived from foci of myosin II filaments in a manner similar to what has been demonstrated in fission yeast.

Significant reduction of antibiotic consumption and patients' costs after an action plan in China, 2010-2014.

INTRODUCTION: On July 1, 2011, the Chinese government launched a national Action Plan for antibiotic stewardship targeting antibiotic misuse in public hospitals. The aim of this study was to evaluate the impacts of the Action Plan in terms of frequency and intensity of antibiotic utilization and patients costs in public general hospitals. METHODS: Administrative pharmacy data from July 2010 to June 2014 were sampled from 65 public general hospitals and divided into three segments: (1) July 2010 to June 2011 as the preparation period; (2) July 2011 to June 2012 as the intervention period; and (3) July 2012 to June 2014 as the assessment period. The outcome measures included (1) antibiotic prescribing rates; (2) intensity of antibiotic consumption; (3) patients costs; and (4) duration of peri-operative antibiotic treatment in clean surgeries of thyroidectomy, breast, hernia, and orthopedic procedures. Longitudinal and cross-sectional analyses were conducted. RESULTS: Longitudinal analyses showed significant trend changes in the frequency and intensity of antibiotic consumption, the patients' costs on antibiotics, and the duration of antibiotic treatment received by surgical patients undergoing the 4 clean procedures during the intervention period. Cross-sectional analyses showed that the antibiotic prescribing rates were reduced to 35.3% and 12.9% in inpatient and outpatient settings, that the intensity of antibiotic consumption was reduced to 35.9 DDD/100 bed-days, that patients' costs on antibiotics were reduced significantly, and that the duration of peri-operative antibiotic treatment received by surgical patients undergoing the 4 types of clean procedures decreased to less than 24 hour during the assessment period. CONCLUSION: The Action Plan, as a combination of managerial and professional strategies, was effective in reducing the frequency and intensity of antibiotic consumption, patients' costs on antibiotics, and the duration of peri-operative antibiotic treatment in the 4 clean surgeries.

Large and giant petroclival meningiomas: therapeutic strategy and the choice of microsurgical approaches - report of the experience with 41 cases.

OBJECTIVE: To evaluate patients' clinical outcome, survival and performance status at the mild-term follow-up evaluation after optimal microsurgical resection of large and giant petroclival meningiomas (PCMs). METHODS: During a 4-year period (2004-2008), 41 patients underwent operative procedures for resection of PCMs. The tumour size was large or giant in 100% of the patients, with a mean tumour diameter of 4.4 cm. Tumours extended into adjoining regions in 26 of the patients. Six previously underwent operation or irradiation. Gross tumour resection (GTR) was accomplished in 25 (61.0%) patients, subtotal resection (STR) in 15 (36.6%) patients and partial resection in 1 (2.4%) patient. There were no operative deaths. Postoperative complications (cerebrospinal fluid leakage, quadriparesis, infections, cranial nerve palsies, etc.) were observed in 27 (65.9%) patients. Postoperative radiation or radiosurgery was administered to 6 of the 41 patients who had residual tumours. RESULTS: At the conclusion of the study, 27 (65.9%) patients were alive with radiological evidence of the residual disease, and 14 (34.1%) patients were alive without radiological evidence of the residual disease. The mean follow-up period was 35 months (range, 15-45 months). Six (14.6%; five of the STR and partially resected patients and one of the total resection patients) had recurrence; of these patients, four underwent repeat resection and two were treated with gamma knife radiosurgery. The Karnofsky Performance Scale score was 78 ±â€Š14 preoperatively, 80 ±â€Š10 at 1 year postoperatively and 81 ±â€Š10 at the time of the latest follow-up evaluation. Common disabilities at the time of the follow-up evaluation included diplopia, facial numbness and swallowing difficulty. Most patients developed coping mechanisms. CONCLUSIONS: The surgical strategy of large and giant PCMs should be focused on the survival and postoperative quality of life. The good surgical approach should be based on the tumour location, the growth direction, the invasion of adjacent structure, the age of the patients and the experience of neurosurgeons. Selectively pursuing an STR without radiotherapy rather than a GTR is a reasonable strategy. Moreover, microneurosurgical technique plays a key role in the level of tumour resection and preservation of nerve function. Intraoperative electrophysiological monitoring also contributes dramatically to the preservation of the nerve function.

[Calcium carbonate precipitation in UASB reactors with different substrates].

Two lab scale upflow anaerobic sludge bed (UASB) reactors were operated at an organic loading rate of COD 9 kg x (m3 x d)(-1) to treat two kinds of calcium containing wastewaters, one of which took acetic acid as substrate and for the other, glucose and soluble starch were the substrate. Both the wastewaters contained 800 mg x L(-1) Ca+. Precipitation of calcium carbonate in the reactors was observed. The results showed that the kind of substrate had great influence on calcium carbonate precipitation. In the reactor treating acetic acid containing wastewater, a maximum calcium precipitation rate of 65% was achieved and an average rate of about 25% was then maintained. In contrast, the calcium precipitation rate for the glucose and soluble starch containing wastewater was only about 7.5%. It was also found that substantial precipitation only occurred 30 days after the reactor were operated for both of the wastewaters. After 180 days of operation, the ash content of the sludge in the reactors increased from about 10% to 70% for the acetic acid containing wastewater and 30% for the other. However, the increase of ash content had no negative influence on the COD removal efficiency, which was kept at about 90% throughout the experimental period. By the SEM it was inferred that the different substrates caused the differences of the granular sludge microstructure, leading to the diversity of calcium carbonate precipitation in the two reactors.

The settling characteristics and mean settling velocity of granular sludge in upflow anaerobic sludge blanket (UASB)-like reactors.

Mean settling velocity of granular sludge in full-scale UASB (upflow anaerobic sludge blanket) and EGSB (expanded granular sludge bed) reactors was evaluated by settling column tests, and a settling velocity model based on the experimental results and available literature data was developed. It is concluded that the settling velocity should be calculated by the Allen formula, because the settling process of the granules is in the category of intermediate flow regime rather than in the laminar flow one. The comparison between calculated and measured values of the settling velocity shows an excellent agreement, with an average relative error of 4.04%. A simple but reliable mathematical method to determine the settling velocity is therefore proposed.