Mineralization of tribromophenol under anoxic/oxic conditions in the presence of copper(II) doped green rust: Importance of sequential reduction-oxidation process.

The groundwater environment often undergoes the transition from anoxic to oxic due to natural processes or human activities, but the influence of this transition on the fate of groundwater contaminates are not entirely understood. In this work, the degradation of tribromophenol (TBP) in the presence of environmentally relevant iron (oxyhydr)oxides (green rust, GR) and trace metal ions Cu(II) under anoxic/oxic-alternating conditions was investigated. Under anoxic conditions, GR-Cu(II) reduced TBP to 4-BP completely within 7 h while GR only had an adsorption effect on TBP. Under oxic conditions, GR-Cu(II) could generate •OH via dioxygen activation, which resulted in the oxidative transformation of TBP. Sixty-five percentage of TBP mineralization was achieved via a sequential reduction-oxidation process, which was not achieved through single reduction or oxidation process. The produced Cu(I) in GR-Cu(II) enhanced not only the reductive dehalogenation under anoxic conditions, but also the O2 activation under oxic conditions. Thus, the fate of TBP in anoxic/oxic-alternating groundwater environment is greatly influenced by the presence of GR-Cu(II). The sequential reduction-oxidation degradation of TBP by GR-Cu(II) is promising for future remediation of TBP-contaminated groundwater.

Pyridinic nitrogen enables dechlorination of trichloroethylene to acetylene by green rust: Performance, mechanism and applications.

Carbonous materials were found to catalyze the dechlorination of trichloroethylene (TCE) by green rust (GR), but the catalytic mechanism was not fully understood. We have developed a facile ball milling method to synthesize N-doped graphene (NG) with various N species, catalyzing fast dechlorination of TCE to acetylene by GR with the highest acetylene production rate of ~0.1 d-1. The adsorption of TCE onto NG is mainly derived from the graphene region of NG, and high pyridinic N is essential for the enhanced TCE reduction by GR. Oxygen species did not enhance the TCE reduction in GR/NG system. High dechlorination rates are correlated to a high amount of defect in NG and a high electron conductivity of NG. Pyridinic N has the highest adsorption energy for TCE among all the N species, which leads to the highest catalytic performance. High electrochemically active surface area resulted from the high content of pyridinic N facilitate the NG-catalyzed dechlorination. The acetylene production rate in real groundwater is still around one-third of that in ultrapure water. This work not only reveals the catalytic mechanism of NG-catalyzed dechlorination by GR, but also provide a feasible approach for practical remediations of TCE-contaminated groundwater using GR-NG mixture.

Response of patients with chest tightness variant asthma with routine asthma treatment regimen: A 1-year multicenter, prospective, real-world study.

BACKGROUND: Asthmatic patients with chest tightness as their only presenting symptom (chest tightness variant asthma [CTVA]) have clinical characteristics of eosinophilic airway inflammation similar to those of classic asthma (CA); however, whether CTVA has similar response to antiasthma treatment as compared with CA remains unclear. OBJECTIVE: The response of 76 CTVA patients to standard asthma treatments with inhaled corticosteroids with long-acting beta-agonists was explored in a 52-week multicenter, prospective, real-world study. RESULTS: After 52 weeks of treatment with therapy regimens used for CA, the mean 5-point Asthma Control Questionnaire (ACQ-5) score decreased markedly from 1.38(first administration) to 0.71 (52 weeks, mean decrease: 0.674, 95%CI: 0.447-0.900, P<.001).The mean asthma quality-of-life questionnaire (AQLQ) score increased from 5.77 (first administration) to 6.20 (52 weeks, mean increase: 0.441, 95% CI 0.258-0.625, P<.001). Furthermore, at week 52, FVC, FEV1 %, the diurnal variation in PEFand the PD20-FEV1 were significantly improved. Subgroup analysis revealed that the patients at first administration in the responsive group had higher ACQ-5 scores than those in the nonresponsive group (P < .05). CONCLUSION: In conclusion, patients with CTVA had a good therapeutic response to the guideline-recommended routine treatment (containing inhaled corticosteroids). The association between the treatment response and the severity of CTVA suggested that CTVA patients with higher ACQ-5 scores had better therapeutic effects.

A novel mathematical model of bone remodelling cycles for trabecular bone at the cellular level.

After an initial phase of growth and development, bone undergoes a continuous cycle of repair, renewal and optimisation by a process called remodelling. This paper describes a novel mathematical model of the trabecular bone remodelling cycle. It is essentially formulated to simulate a remodelling event at a fixed position in the bone, integrating bone removal by osteoclasts and formation by osteoblasts. The model is developed to construct the variation in bone thickness at a particular point during the remodelling event, derived from standard bone histomorphometric analyses. The novelties of the approach are the adoption of a predator-prey model to describe the dynamic interaction between osteoclasts and osteoblasts, using a genetic algorithm-based solution; quantitative reconstruction of the bone remodelling cycle; and the introduction of a feedback mechanism in the bone formation activity to co-regulate bone thickness. The application of the model is first demonstrated by using experimental data recorded for normal (healthy) bone remodelling to predict the temporal variation in the number of osteoblasts and osteoclasts. The simulated histomorphometric data and remodelling cycle characteristics compare well with the specified input data. Sensitivity studies then reveal how variations in the model's parameters affect its output; it is hoped that these parameters can be linked to specific biochemical factors in the future. Two sample pathological conditions, hypothyroidism and primary hyperparathyroidism, are examined to demonstrate how the model could be applied more broadly, and, for the first time, the osteoblast and osteoclast populations are predicted for these conditions. Further data are required to fully validate the model's predictive capacity, but this work shows it has potential, especially in the modelling of pathological conditions and the optimisation of the treatment of those conditions.