Multi-walked carbon nanotube (MWCNT)/poly(aryl ether ketone) networks cross-linked by Diels-Alder cycloaddition possess outstanding mechanical and rheological properties. Poly(aryl ether ketone) ...containing pendant furan (PAEK-Fu) was synthesized, which had excellent thermal and mechanical properties, and a series of cross-linked materials with reversible covalent cross-linked crosslinking network were synthesized through a furan/MWCNTs Diels-Alder (D-A) reaction between PAEK-Fu and MWCNTs. Thermal and mechanical properties for MWCNT/PAEK-Fu composites were studied, and after crosslinking, MWCNT/PAEK-Fu composites exhibited good flexibility and resistance against organic solvents. After heating to 180 °C, the cross-linked MWCNT/PAEK-Fu composite membranes could be dissolved in NMP. This work demonstrates that the poly(aryl ether ketone)s can be made into recyclable thermoset materials using the concept of associative dynamic bonding. Given the dramatically increasing interest in environmentally sustainable materials, this MWCNT/poly(aryl ether ketone) interaction mode provides a robust approach to high performance engineering plastics with improved performance compared with the thermoplastic counterparts.
•A bio-electro-Fenton system was set up.•Estrogens were removed in the system due to adsorption and oxidation.•Two probable degradation pathways were proposed for E2.•The system was cost-effective ...for recalcitrant contaminants treatment.
The feasibility of removing estrogens including 17β-estradiol (E2) and 17α-ethynyl-estradiol (EE2) was studied in a bio-electro-Fenton (BEF) system equipped with a Fe@Fe2O3/non-catalyzed carbon felt (NCF) composite cathode. E2 and EE2 were removed by reactive oxidants, produced by bio-electro-Fenton system and zero-valent iron/O2 system, as well as adsorption. Under closed-circuit condition, 81% of E2 and 56% of EE2 were removed within 10h in the system, in which the highest concentration of total iron ions and H2O2 reached 81 and 1.2mg/L, respectively. The maximum power density of BEF system equipped with Fe@Fe2O3/NCF electrode was 4.35W/m3. Two intermediates of E1 and 6-OH-E2 were identified during Fenton oxidation of E2. This study demonstrates the degradation fate of E2 and EE2 in a BEF system equipped with Fe@Fe2O3/NCF electrodes, which provides a promising and cost-effective solution for the removal of recalcitrant contaminants with simultaneous power generation.
Introduction
Conflict monitoring and processing is an important part of the human cognitive system, it plays a key role in many studies of cognitive disorders.
Methods
Based on a Chinese word-color ...match Stroop task, which included incongruent and neutral stimuli, the Electroencephalogram (EEG) and functional Near-infrared Spectroscopy (fNIRS) signals were recorded simultaneously. The Pearson correlation coefficient matrix was calculated to analyze brain connectivity based on EEG signals. Granger Causality (GC) method was employed to analyze the effective connectivity of bilateral frontal lobes. Wavelet Transform Coherence (WTC) was used to analyze the functional connectivity of the bilateral hemisphere and ipsilateral hemisphere.
Results
Results indicated that brain connectivity analysis on EEG signals did not show any significant lateralization, while fNIRS analysis results showed the frontal lobes especially the left frontal lobe play the leading role in dealing with conflict tasks. The human brain shows leftward lateralization while processing the more complicated incongruent stimuli. This is demonstrated by the higher functional connectivity in the left frontal lobe and the information flow from the left frontal lobe to the right frontal lobe.
Discussion
Our findings in brain connectivity during cognitive conflict processing demonstrated that the dual modality method combining EEG and fNIRS is a valuable tool to excavate more information through cognitive and physiological studies.
This study was designed to evaluate the safety and pharmacokinetic profiles of MRX-I tablet, an oxazolidinone antibacterial agent, in healthy Chinese subjects.
The study was composed of 3 sequential ...periods. Period 1 was a randomized, double-blind, placebo-controlled, sequential ascending dose (50 to 1800 mg) study. Period 2 included one arm as a randomized, open-label, 3-period, 3 × 3 Latin square single-dose study of 300, 600, and 900 mg MRX-I administration and another arm as a crossover study to evaluate high-fat diet effect. Period 3 was a randomized, double-blind, placebo-controlled multiple-dose study with 600 or 800 mg, q12h regimens over 15 days.
MRX-I was rapidly absorbed and reached peak plasma concentration at about 2 hours post dose. The Cmax was 8.07, 12.24, and 15.25 mg/L and the corresponding AUC0−∞ 29.21, 48.27, and 59.60 mg/h/L, in 300-, 600-, and 900-mg dosing groups, respectively. High-fat diet increased the exposure of MRX-I. No discernable drug accumulation was observed after 15 days of continuous drug administration. About 2% of MRX-I was excreted via kidneys in unchanged form. No obvious hematologic toxicity by MRX-I was observed during the entire study. Based on Monte Carlo simulation, 600 or 800 mg BID can produce satisfactory efficacy against methicillin-resistant Staphylococcus aureus.
MRX-I was well tolerated in healthy Chinese subjects (50–1800 mg). No serious or severe adverse effects were observed. MRX-I 600 or 800 mg BID up to 15 days can be recommended in future clinical trials. Chinese Clinical Trial Registration (http://www.chinadrugtrials.org.cn) identifier: CTR20131214.
Lycopene is a kind of natural food ingredient that is one of the strongest antioxidants in nature at present. However, the mechanism of scavenging singlet oxygen is still unclear which has restricted ...the extensive application of lycopene in many fields. Density functional theory has been applied to optimize the configurations of the ground and excited states of lycopene and oxygen respectively. The quenching mechanism of singlet oxygen by lycopene is analyzed based on the calculations at the B3LYP/6-311+(d,p) level. The excited state oxygen in the singlet turns into the ground state in the triplet and gives out energy, while at the same time lycopene in the ground state absorbs the energy, changing into excited lycopene. The quenching process involves exchange of two electrons of different spin coming from lycopene and singlet oxygen. The quenching is spontaneous according to the calculated energy and Gibbs free energy change. Regarding energy level and the construction of frontier orbitals, electron exchange occurs simultaneously with energy transfer and change of spin. In addition, it also can be concluded that oxygen and lycopene can pass electric charge to each other in the meantime, however, it is dominated by one or the other in different stages. Overall, the close energy levels and good symmetry matching of the reactants’ frontier orbitals, lack of electron spin-flip in the quenching system, and the negative Gibbs free energy difference, all make the quenching process very easy.
Bloodstream infections (BSIs), especially hospital-acquired BSIs, are a major cause of morbidity and mortality. However, the details about the pathogens and antimicrobial resistance profile of BSIs ...across China are still lacking.
An investigation was conducted in 10 large teaching hospitals from seven geographic regions across China in 2016 based on China Antimicrobial Surveillance Network (CHINET) to profile the clinical and etiological features of BSIs.
A total of 2,773 cases of BSIs were identified, a majority (97.3%) of which were monomicrobial. Overall, 38.4% (1,065/2,773) were community-acquired BSIs (CABSIs), and 61.6% (1,708/2,773) were hospital-acquired BSIs (HABSIs). Of the 2,861 pathogenic BSI isolates, 67.5% were Gram-negative bacteria, 29.6% were Gram-positive bacteria, and 2.9% were fungi. The top BSI pathogens were
,
, coagulase-negative
(CNS),
,
, and
.
and
isolates showed low susceptibility to penicillins, cephalosporins (except ceftazidime and cefepime), and ampicillin-sulbactam (13.1%-43.4% susceptible); moderate susceptibility (about 60% susceptible) to ceftazidime, cefepime, and aztreonam; and high susceptibility (>90%) to β-lactam/β-lactamase inhibitor combinations other than ampicillin-sulbactam, except
strains to piperacillin-tazobactam (59.2% susceptible). HABSIs were associated with significantly higher prevalence of carbapenem-resistant and extended-spectrum β-lactamases-producing
, methicillin-resistant
, methicillin-resistant CNS, and ampicillin-resistant
than CABSIs. Overall, 42.0% of the BSI due to
strains were resistant to methicillin.
The findings about BSIs in teaching hospitals across China add more scientific evidence to inform the appropriate management of the disease.
Nemonoxacin is an innovative quinolone antibiotic for treatment of community-acquired pneumonia (CAP). As more data are available from clinical studies, it is necessary to perform an integrative ...pharmacokinetic/pharmacodynamic (PK/PD) analysis to support and justify the optimal dosing regimen of nemonoxacin in clinical practice.
We developed a population PK model using non-linear mixed effect model based on the data of 195 Chinese subjects receiving nemonoxacin in phase I to III clinical trials. The base model was a standard two-compartment PK model defined by clearance (12 L/h) and central volume of distribution (86 L). Covariates included creatinine clearance (CL
), body weight (BW), sex, disease status and food. Compared to the subject with BW 60 kg, C
and
reduced by 24% and 19% in the subject with BW 80 kg, respectively. Compared to the subject with CL
150 ml/min,
and T
increased by 28% and 24%, respectively in the subject with CL
30 ml/min. Compared to the fasted status, T
of nemonoxacin increased by 1.2 h in the subject with fed status. Effects of sex and disease status on PK parameters were small (change of PK parameters ≤19%). AUC
/MIC and %T > MIC were identified as the optimal PK/PD indices for predicting clinical efficacy. The AUC
/MIC target was 63.3, 97.8, and 115.7 against
,
, and
, respectively. The %T > MIC target was 7.96% against
. Monte Carlo simulation showed that treatment with nemonoxacin 500 mg q24 h could attain a PK/PD cutoff value higher than the MIC
against
and
. The corresponding cumulative fraction of response (CFR) was greater than 93%, while nemonoxacin 750 mg q24 h would provide higher PK/PD cutoff value against
, and higher CFR (83%) than 500 mg q24 h.
Integrative PK/PD analysis justifies the reliable clinical and microbiological efficacy of nemonoxacin 500 mg q24 h in treating CAP caused by
,
, and
, irrespective of patient sex, mild renal impairment, empty stomach or not. However, nemonoxacin 750 mg q24 h would provide better efficacy than 500 mg q24 h for the CAP caused by
in terms of CFR.
Carbapenems such as imipenem and meropenem are first-line agents for the treatment of serious nosocomial infections caused by multidrug-resistant clinical isolates of bacteria belonging to the family ...Enterobacteriaceae. However, resistance to carbapenems has increased dramatically among members of the family Enterobacteriaceae isolated from a teaching hospital in Shanghai, China. In the present study, we investigated the prevalence and molecular characteristics of carbapenem-resistant clinical isolates of Enterobacteriaceae. None of the 77 clinical isolates collected from 2002 to 2009 were susceptible to ertapenem and only 6.5 % and 1.3 % of isolates were susceptible to imipenem and meropenem, respectively. Colistin and tigecycline were found to be the most active agents against carbapenem-resistant Enterobacteriaceae isolates, inhibiting 90 % of isolates at a concentration of 1 µg ml(-1) and 4 µg ml(-1), respectively. The results of PFGE analysis suggested that many of the KPC-2-producing isolates of Citrobacter freundii and Klebsiella pneumoniae were clonally related. Most of these isolates were isolated from the same ward, namely the neurosurgical ward, suggesting horizontal transfer of the KPC-2-encoding gene in these isolates. Of the 77 isolates, 84.4 % were found, by PCR, to be capable of carbapenemase production. SDS-PAGE analysis revealed that 75.3 % (58/77) of the isolates had lost at least one porin protein. Our results suggested that the prompt detection of carbapenemase-producing strains is critical for the containment of nosocomial transmission. As no novel antimicrobials have been identified for use in the treatment of these pan-drug-resistant isolates, further studies should focus on the rational use of available antibiotics, the implementation of active antibiotic resistance surveillance and the strict implementation of infection control measures to avoid the rapid spread or outbreak of carbapenemase-producing Enterobacteriaceae in health-care facilities.
Adequate detection of the production of carbapenemase in Enterobacteriaceae isolates is crucial for infection control measures and the appropriate choice of antimicrobial therapy. In this study, we ...investigated the frequency of false positive results for the detection of carbapenemases in carbapenemase-negative Escherichia coli and Klebsiella pneumoniae clinical isolates by the modified Hodge test (MHT). Three hundred and one E. coli and K. pneumoniae clinical isolates were investigated. All produced extended spectrum β-lactamases (ESBLs) but were susceptible to carbapenems. Antimicrobial susceptibility testing was performed by the disk diffusion and agar dilution methods. The MHT was performed using the standard inoculum of test organisms recommended by the CLSI. Genes that encoded ESBLs and carbapenemases were identified by PCR and DNA sequencing. Among the 301 clinical isolates, none of the isolates conformed to the criteria for carbapenemase screening recommended by the CLSI. The susceptibility rates for imipenem, meropenem, and ertapenem all were 100.0%, 100.0%, and 100.0%, respectively. Of the 301 E. coli and K. pneumoniae isolates, none produced carbapenemase. The MHT gave a positive result for 3.3% (10/301) of the isolates. False positive results can occur when the MHT is used to detect carbapenemase in ESBL-producing isolates and clinical laboratories must be aware of this fact.
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