Novel Cu(II)Cd(II) macrocyclic complex that hydrolyzes an activated phosphate diester

The dinucleating macrocyclic ligand 3,6,9,17,20,23-hexaaza-29,30-dihydroxy-13,27-dimethyl-tricyclo[23,3,1,1^11,15] triaconta-1(28),11,13,15(30),25,26,-hexaene(BDBPH) was synthesized from [2+2] condensation between a diethylenetriamine lead(II) mononuclear complex and diformal-p-cresol. By stepwise synthesis, the heterodinuclear Cu(II)Cd(II) complex was obtained. The single crystal was triclinic, space group P1, with cell constants a=13.2675(10) Å, b=16.4655(13) Å, c=17.9502(14) Å, α=87.78(10), β=68.69(10), γ=74.81(10), V=3517.6(3) Å and Z=4. Potentiometric titration reveals that Cu(II)Cd(II)BDBPHOH species dominate in basic solution from pH 7 to 12. In the hydrolysis of BNP, this dinuclear complex can provide both Lewis acid and base sites to an active phosphate diester in which nucleophilic OH⁻ attacks the substrate to fulfill the hydrolysis cycle. In this system the synergic two functional groups in one catalyst molecule exerted remarkable catalytic activity towards hydrolysis of BNP.     

Influence of the activated sludge system configuration on heavy metal toxicity reduction

The effect of configuration of activated sludge systems on heavy metal toxicity was investigated. Two bench-scale completely mixed activated sludge systems were operated identically in order to determine the toxic effects of Cr(VI), Zn(II) and industrial wastewater on the activated sludge biomass. One system was operated with an aerobic selector and the other without. Batch experiments based on OECD 209 (Organisation for Economic Cooperation and Development) were performed using a respirometer to find out potential toxicity reduction effect of an aerobic selector. The IC₅₀ (concentration of a chemical that exhibits 50% respiration inhibition) values of Cr(VI), Zn(II) and industrial wastewater in the activated sludge were determined. Results indicated that the heavy metals and industrial wastewater caused less inhibitory effect on the selector activated sludge system in comparison to the conventional activated sludge system. Cr(VI) was found to exert higher inhibition on both systems.     

Predicted multiple selected reaction monitoring to screen activated drug-mediated modifications on human serum albumin

Metabolic activation of drugs frequently generates electrophilic products that may undergo covalent binding to biological macromolecules, such as proteins and DNA. The resulting covalent adducts are of considerable concern in drug discovery and development. Several strategies for assessing the potential risks of candidate drugs have been reported. Of these, glutathione trapping is the most commonly used method together with mass spectrometry. Furthermore, drug-mediated protein modifications have been studied using serum albumin and CYP enzymes to clarify target amino acids and mechanism-based inhibition, respectively. In this article, we introduce a practical way to screen drug-mediated protein modifications. The method, referred to as “predicted multiple selected reaction monitoring,” is based on the selected reaction monitoring (SRM) strategy, but targets all possible chemically modified tryptic peptides. The creation of SRM lists may require patience; however, this strategy could facilitate more sensitive screening compared with the common strategy of data-dependent product ion scanning. Ketoprofen-N-hydroxysuccinimidyl ester (equivalent to glucuronide) and N-acetyl-p-benzoquinone imine (NAPQI) were allowed to react with human serum albumin as a model experiment. Using this strategy, 11 ketoprofen-adduction sites (at Lys^{137, 195, 199, 212, 351, 402, 432, 436, 525, 536, and 541}) and 1 NAPQI-adduction site (at Cys³⁴) were easily identified.     

Stability of Activated Persulfate in the Presence of Aquifer Solids

Bench-scale experiments were performed to investigate the persistence of activated persulfate using citric acid (CA) chelated ferrous (Fe(II)), peroxide (H₂O₂), or hydroxide (OH^?) activation in the presence of well-characterized aquifer solids. Chelation by citric acid was ineffective in controlling the interaction between persulfate and Fe(II), and oxidation of Fe(II) was observed, causing a rapid initial decrease in persulfate concentration. Subsequent to this loss, first-order persulfate degradation rate coefficients (k_obs) were estimated, which were up to four times higher than the unactivated case due to the interaction with Fe(III), Fe(II), or CA. Total oxidation strength (TOS) was measured for peroxide activation experiments and was observed to decrease rapidly early due to peroxide degradation. This was followed by slow degradation kinetics similar to that of unactivated persulfate, implying that the initial TOS degradation was peroxide-dominated and the long-term kinetics were dominated by persulfate degradation. The k_obs later used to capture TOS degradation were ～1 to 100 times higher than k_obs for unactivated persulfate. For alkaline activation, k_obs were only one to four times higher than unactivated persulfate, and therefore alkaline conditions demonstrated the least overall impact on persulfate stability among the various activation strategies explored.     

Smad3基因剔除的骨髓细胞移植对小鼠的影响

目的通过小鼠骨髓细胞剔除Smad3基因,观察小鼠病理变化以及免疫T细胞状态。方法将Smad3基因剔除Smad3-/-)的小鼠骨髓细胞和野生型(Smad3+/+)小鼠骨髓细胞分别移植给60Co射线照射GFP小鼠。观察骨髓移植后GFP小鼠体征变化,第6周处死小鼠,取肠道固定,HE染色观察其病理变化,流式细胞技术检测淋巴结中T细胞变化。结果移植Smad3-/-骨髓细胞的GFP小鼠逐渐消瘦,大肠出现炎症;淋巴结中活化型的CD4+CD62LloT细胞增多。结论骨髓细胞TGF-β信号受阻,可导致小鼠患炎症疾病,引起免疫T细胞活化。     

Phenol and phenolics from lignocellulosic biomass by catalytic microwave pyrolysis

Catalytic microwave pyrolysis of biomass using activated carbon was investigated to determine the effects of pyrolytic conditions on the yields of phenol and phenolics. The high concentrations of phenol (38.9%) and phenolics (66.9%) were obtained at the temperature of 589 K, catalyst-to-biomass ratio of 3:1 and retention time of 8 min. The increase of phenol and its derivatives compared to pyrolysis without catalysts has a close relationship with the decomposition of lignin under the performance of activated carbon. The concentration of esters was also increased using activated carbon as a catalyst. The high content of phenols obtained in this study can be used either directly as fuel after upgrading or as feedstock of bio-based phenols for chemical industry.     

Effects of glucose and phenol on soluble microbial products (SMP) in sequencing batch reactor systems

Soluble microbial products (SMP) are ubiquitously present in the effluents of biological wastewater treatment systems. In sequencing batch reactor (SBR) systems, effects of influent concentration and temperature on the amount and the molecular weight (MW) distribution of SMP were investigated for the two substrates, glucose and phenol. The values of effluent SMP/S₀ of phenol were higher than those of glucose at different influent concentrations and temperatures. It was found that the effluent SMP (S_e) was linearly correlated to the influent total organic carbon (TOC) (S₀) for both substrates. The slope and intercept of the equation were affected by the temperature. According to the analysis of the MW distribution, it was shown that there exists a bimodal pattern with the majority of SMP having a MW<1 kDa or >10 kDa. The low MW fraction (<1 kDa) amounts to 47.3–70.4% of the effluent SMP. The high MW fraction (>10 kDa) slightly fluctuates in the range of 21.2–32.8% of the effluent SMP.     

Phenol-mediated improved performance of active biomass for treatment of distillery wastewater

Activated sludge from a wastewater treatment plant consists of a consortium of microbes that utilize various organic molecules including persistent organic pollutants for their survival. Phenolic compounds and their derivatives along with dibenzofuran (DBF) are found as dominating pollutants in distillery waste. The acclimatization process leads to selective enrichment of the microbial community; and in this study, we report the acclimatizing effect of phenol on improving the treatment efficiency of two different distillery sludges—sludge from conventional aeration tanks (CAT), and from an extended aeration tank (EAT). The adaptation-dependent performance of activated biomass was studied by monitoring the increase in colony-forming units (CFUs) on mineral media and the utilization pattern for phenol (300×10³ and 530×10³ CFU for CAT and EAT sludge, respectively) and DBF (260×10³ and 430×10³ CFU for CAT and EAT sludge, respectively). The study showed that the acclimatization process remarkably improved the performance sludge for treatment of distillery wastewater. There was an improvement in chemical oxygen demand (COD) removal efficiency from 19% (unacclimatized sludge) to 31% in the case of acclimatized sludge (raw wastewater), which improved further to 82% and 87% with dilution of wastewater by 10 times (0.1×) and by 50 times (0.02×), respectively. Highest growth yields were observed with 0.1× wastewater (0.324 and 0.308 g g⁻¹ d⁻¹ for CAT and EAT sludges, respectively), while lower values are reported for the remaining two forms of wastewater. The study proposes that acclimatization step could be included as part of a treatment plant where the activated biomass could be intermittently metabolically charged by exposing it to selected molecules to increase treatment efficiency.