Relationship between electrocardiogram QRS wave duration and pathological parameters of patients with acute myocardial infarction and prognosis analysis / 中国医师杂志

Objective:To explore the relationship between electrocardiogram QRS wave duration and pathological parameters of acute myocardial infarction and its prognosis.Methods:The patients with acute myocardial infarction treated in Hunan Brain Hospital from January 2018 to June 2019 were divided into normal group (≤110 ms, NG group) and extended group (>110 ms, EG group) according to the time limit of QRS wave group of electrocardiogram (ECG). The clinicopathological data of the two groups were collected, and the differences of relevant pathological parameters between the two groups were compared. The correlation between ECG QRS complex time limit and pathological parameters of acute myocardial infarction and the independent risk factors affecting the occurrence of malignant cardiovascular events after acute myocardial infarction were analyzed.Results:A total of 134 patients were enrolled, 73 in the EG group, and 61 in the NG group. The plasma levels of N-terminal pro-brain natriuretic peptide (N-proBNP) in EG group were significantly higher than those in NG group ( P<0.05), and left ventricular ejection fraction (LVEF) was significantly lower than that in NG group ( P<0.05). The time limit of QRS wave group in EG group was positively correlated with the plasma levels of N-proBNP ( r=0.981, P<0.001) and negatively correlated with LVEF ( r=-0.979, P<0.001). The ratio of Killip grade Ⅰ patients in EG group were lower than those in NG group ( P<0.05), while the ratio of grade Ⅱ and Ⅲ patients were significantly higher than those in NG group ( P<0.05), and there was no significant difference between the two groups in grade Ⅳ patients ( P>0.05). The incidence of malignant cardiovascular events (cardiogenic shock, malignant arrhythmia, acute pulmonary edema, cardiogenic death and re-infarction) in EG group was significantly higher than that in NG group ( P<0.05). Multivariate logistic regression analysis showed that elevated serum N-proBNP, decreased LVEF, prolonged QRS wave duration and high Killip cardiac function were independent risk factors for malignant cardiovascular events after acute myocardial infarction. Conclusions:After acute myocardial infarction, EG patients have worse cardiac function, higher incidence of malignant cardiovascular events and worse prognosis than NG patients.

Field study of nitrous oxide production with in situ aeration in a closed landfill site.

UNLABELLED: Nitrous oxide (N(2)O) has gained considerable attention as a contributor to global warming and depilation of stratospheric ozone layer. Landfill is one of the high emitters of greenhouse gas such as methane and N(2)O during the biodegradation of solid waste. Landfill aeration has been attracted increasing attention worldwide for fast, controlled and sustainable conversion of landfills into a biological stabilized condition, however landfill aeration impel N(2)O emission with ammonia removal. N(2)O originates from the biodegradation, or the combustion of nitrogen-containing solid waste during the microbial process of nitrification and denitrification. During these two processes, formation of N(2)O as a by-product from nitrification, or as an intermediate product of denitrification. In this study, air was injected into a closed landfill site and investigated the major N(2)O production factors and correlations established between them. The in-situ aeration experiment was carried out by three sets of gas collection pipes along with temperature probes were installed at three different distances of one, two and three meter away from the aeration point; named points A-C, respectively. Each set of pipes consisted of three different pipes at three different depths of 0.0, 0.75 and 1.5 m from the bottom of the cover soil. Landfill gases composition was monitored weekly and gas samples were collected for analysis of nitrous oxide concentrations. It was evaluated that temperatures within the range of 30-40°C with high oxygen content led to higher generation of nitrous oxide with high aeration rate. Lower O(2) content can infuse N(2)O production during nitrification and high O(2) inhibit denitrification which would affect N(2)O production. The findings provide insights concerning the production potentials of N(2)O in an aerated landfill that may help to minimize with appropriate control of the operational parameters and biological reactions of N turnover. IMPLICATIONS: Investigation of nitrous oxide production potential during in situ aeration in an old landfill site revealed that increased temperatures and oxygen content inside the landfill site are potential factors for nitrous oxide production. Temperatures within the range of optimum nitrification process (30-40°C) induce nitrous oxide formation with high oxygen concentration as a by-product of nitrogen turnover. Decrease of oxygen content during nitrification leads increase of nitrous oxide production, while temperatures above 40°C with moderate and/or low oxygen content inhibit nitrous oxide generation.

Spectroscopic studies of the effect of aerobic conditions on the chemical characteristics of humic acid in landfill leachate and its implication for the environment.

Humic acids (HAs) that extracted from leachates from semi-aerobic and anaerobic landfills test field at different stabilization times were characterized by elemental composition, Fourier transform infrared spectroscopy (FTIR), and Carbon-13 Cross-Polarization Magic-Angle-Spinning Nuclear Magnetic Resonance ((13)C CP/MAS NMR). The higher sulfur (S) content of HA in the anaerobic landfill leachate after a short stabilization time showed that the S released from the organic matter degradation was more easily stabilized under anaerobic conditions, which indicate that HA from anaerobic landfill leachate was more chemically reactive and played a more important role in mobilizing heavy metal, especially mercury, at early landfill stabilization times. However, the S content of HA from the semi-aerobic landfill increased over time, suggesting that more S was stabilized in HA as the landfill stabilization time was extended. The analytical results for the FTIR and NMR showed that the HA from the anaerobic landfill contained more aromatic groups, while HA from the semi-aerobic landfill had more oxygen-containing groups. The aromatic components of the HA from both the anaerobic and semi-aerobic landfills increased over time, suggesting that the maturity and humification degree of HA increased during the stabilization process.

Fluorescence excitation-emission matrix combined with regional integration analysis to characterize the composition and transformation of humic and fulvic acids from landfill at different stabilization stages.

Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with fluorescence regional integration (FRI) analysis was used to investigate the composition and transformation of humic acid (HA) and fulvic acid (FA) from landfill. The EEMs of HAs at different landfill ages were characterized by two typical fluorescence chromophores with Ex/Em pairs at Ex=420-470 nm/Em=490-530 nm and Ex=345-375 nm/Em=450-465 nm. EEMs of FA were featured by other two distinctly different fluorophores with Ex/Em pairs at Ex=315-335 nm/Em=420-440 nm and Ex=255-275 nm/Em=425-455 nm. The results show that HA extracted from the refuse disposed in the year of 1989 was formed by connecting small-condensed aromatic structures with protein-like chains. Compared with HA extracted from the refuse disposed in the year of 1992, HA extracted from the refuse of 1996 had a higher fluorescence intensity and lower r(()(B)(,)(A)()) (the ratio of the fluorescence intensities of peak B and peak A) value. It contained low molar mass components, low aromatic condensation degree, and more easily oxidized substituents. This indicates that the landfill time strongly affects the EEMs characteristics of HA, and that the humification degree of HA increases with the landfill time. A red shift to a longer wavelength region and an increase of fluorescence intensity were observed when the concentration of HA was increased, suggesting that concentration had a great influence on the fluorescence characteristics of HAs. pH (2-12) also had significant effects on the fluorescence intensity, although it exerted no effect on the peak position of fluorescence of HA and FA. The results of FRI show that increasing concentration lead to more interactions among various structure components and that small molecular weight units tend to aggregate or be masked into more complicated and larger structures. The pH influence on the fluorescence intensity of HA seems mainly through molecular configuration, while the fluorescence intensity change with pH may be due to various substituents of FA.

Effects of fulvic substances on the distribution and migration of Hg in landfill leachate.

Mercury (Hg) distribution and migration in different landfill stabilization processes were evaluated in this study. Wide ranges of Hg concentrations were observed because of the heterogeneity and variability of landfill refuse. In addition, temporally variable conditions, including pH, organic matter, and vegetation cover, which influence Hg migration in landfills, may also affect the temporal distribution of Hg in landfill refuse. The main fraction of Hg, elemental Hg, decreased with time, while the stable fractions of Hg increased. The fulvic acid (FA) extracted from the landfill leachate had much lower overall Hg-complexation stability constants, which suggests that organic S groups might have been rapidly saturated by small amounts of Hg while leaving oxygen functional groups, such as carboxylic functional or phenolic groups, acting as the primary binding sites for Hg.

Abiotic association of PAEs with humic substances and its influence on the fate of PAEs in landfill leachate.

An equilibrium dialysis combined with a (14)C-labeling method was used to study the abiotic association of phthalic acid esters (PAEs) with dissolved humic substances (HS) and its influence on the fate of PAEs in landfill leachate. Elemental analysis and FTIR spectral analysis were carried out on the humic acid (HA) and fulvic acid (FA) components of HS to examine the relationship between the structure of HS and the intensity of the association of the PAEs with HS (K(A)). The results show that the association intensity of HS with PAEs depends greatly on both the properties of the PAEs and the source of HS. The HS have a strong association reaction with dibutyl phthalic acid, which might explain the higher concentration of dibutyl phthalic acid detected in landfill leachate. The pH value strongly affects the K(A) of HS, and it decreases radically when the pH increase from 3.0 to 9.0. The non-specific hydrophobic interaction between HS and PAEs plays a more important role in the abiotic association of HS with PAEs. Elemental analysis and FTIR spectra suggest that the high K(A) values are related to the high aromatic content and larger molecular weight of HS.

Characteristics of environmental factors and their effects on CH4 and CO2 emissions from a closed landfill: an ecological case study of Shanghai.

To elucidate the influence of landfill gas (LFG) emission on environmental factors, an ecological investigation that was primarily concerned with the characteristics of vegetation, cover soil, and solid waste in the landfill was carried out. Temporal and spatial variations in vegetation diversity and coverage and their effects on reducing the emission of methane in the landfill were investigated. The results showed that both vegetation coverage and diversity increased with elapsed landfill closure time. The transition trend of the vegetation species was from perennial plant (Phragmites australis) to annual plants. Perennial vegetation was the dominant type of vegetation during the early closure period, and annual vegetation coverage increased with closure time. Vegetation preferentially appeared in areas of comparatively high depth of cover soil, which was characterized by high moisture retentiveness that enabled vegetation growth. The concentrations of methane and carbon dioxide in the cover soil significantly decreased with increasing closure time. The concentrations of methane and carbon dioxide from bare cover soil were higher than those from vegetated cover soil whereas the CO(2) flux of bare cover soil was less than that of vegetated cover soil.

Biomimetic fat cell (BFC) modification and for lindane removal from aqueous solution.

To improve the regeneration ability of biomimetic fat cell (BFC), an innovative agent for hydrophobic organic contaminants (HOCs) removal, BFC was modified through introducing 1, 3, 5-benzenetricarboxyl trichloride with trifunctional group and heterocyclic piperazine in this research. Modified biomimetic fat cell (MBFC) has a good lindane removal capacity close to that of BFC and powder activated carbon (PAC), and the lindane removal is 97.68, 96.65 and 98.36% with 7 mg/L lindane initial concentration, respectively. At the same time, 20 mg/L MBFC or PAC is sufficient for 10 microg/L lindane removal, and in 20-60 mg/L doses range the lindane removal by both MBFC and PAC can reach 99.0%; When the doses is below 10 mg/L, MBFC showed better lindane removal than PAC and MBFC even could reach 96.8% lindane removal in 5 mg/L dose. Lindane removal by MBFC could be held on 95% above in first 6-time reuse. Though the lindane removal by MBFC decreased with the reuse time increasing, MBFC still could remove 80 % lindane after 9 times regeneration. In contract with BFC, MBFC showed obvious advantage on the regeneration. The lindane removal mechanism by MBFC, similar with BFC, includes bioaccumulation by MBFC nucleolus-triolein and adsorption by MBFC membrane, and the bioaccumulation is the main way.

Characterization of humic and fulvic acids extracted from landfill by elemental composition, 13C CP/MAS NMR and TMAH-Py-GC/MS.

Humic acid (HA) and fulvic acid (FA) extracted from landfills at different landfill ages were characterized by elemental composition, (13)C CP/MAS NMR, and TMAH-Py-GC/MS. The elemental composition analysis revealed high O/C and low H/C ratios in the FA, indicating a high proportion of O-alkyl and carboxylic acids in the FA. The analytical results of (13)C CP/MAS NMR suggested that there were more oxygenated aliphatic carbons and fewer aromatic carbons in FA than in HA. The Py-GC/MS products showed that the HA and FA extracted from the refuse in the landfill were mainly composed of various lignin-derived compounds. Oxidized aromatic acid derivatives originated from the oxidation of side-chains of lignin-like compounds, and this process played a significant role in the process of HA and FA formation in the landfill. All of the results demonstrated that the degree of humification increased with landfill age.

Biomimetic fat cell (BFC) preparation and for lindane removal from aqueous solution.

Fat tissue of organism can accumulate hydrophobic chemicals efficiently and the accumulation level has a positive correlation with fat quantity. In this work, based on this characteristic, an innovative agent, that is, biomimetic fat cell (BFC) has been synthesized with interfacial polymerization. BFC has a hydrophobic nucleolus-triolein and hydrophilic membrane-polyamide, through which water, carrying hydrophobic organic contaminants (HOCs), can pass. This process is followed by the accumulation of HOCs. BFC has 97.39% lindane removal ability. This is close to 98.12% lindane removal by powder active carbon (PAC) in aqueous solution and 7 mg/L initial concentration of lindane. BFC can be regenerated easily by organic solvent dialysis in comparison with high temperature or pressure used for PAC regeneration. Lindane removal by BFC may occur through two mechanisms: bioaccumulation by BFC nucleolus-triolein; and adsorption by BFC membrane. Bioaccumulation is the prevailing mechanism.

Characteristics and mobility of heavy metals in an MSW landfill: implications in risk assessment and reclamation.

To assess the reclamation feasibility of a landfill, the characteristics, distribution, and mobility of heavy metals in the landfill were investigated. The refuse was characterized as containing high concentrations of heavy metals, a relatively high pH, and a high ratio of NH(4)-N to total nitrogen (TN). The results of heavy metal distribution showed that relatively high levels of heavy metals were accumulated in the landfill. Sequential extraction revealed that the relative amounts of heavy metals were different in the samples. Zn demonstrated the greatest mobility compared to other heavy metals, whereas Cd was well retained in the landfill. Leaching experiments indicated that the mobility of heavy metals in the landfill was generally low under normal neutral conditions. However, release of heavy metals can be increased greatly when medium conditions become more acidic and aerobic.

Adsorption of phenolic compound by aged-refuse.

The adsorption of phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol by aged-refuse has been studied. Adsorption isotherms have been determined for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol and the data fits well to the Freundlich equation. The chlorinated phenols are absorbed more strongly than the phenol and the adsorption capacity has an oblivious relationship with the numbers and the position of chlorine subsistent. The experiment data suggests that both the partition function and the chemical adsorption involve in the adsorption process. Pseudo-first-order and pseudo-second-order model were applied to investigate the kinetics of the adsorption and the results show that it fit the pseudo-second-order model. More than one step involves in the adsorption process and the overall rate of the adsorption process appears to be controlled by the chemical reaction. The thermodynamic analysis indicates that the adsorption is spontaneous and endothermic.