Continuous treatment of diethyl hexyl and dibutyl phthalates by fixed-bed reactor: Comparison of two esterase bionanocomposites

The removal of Diethyl hexyl phthalate (DEHP) and Dibutyl phthalate (DBP) is of great importance due to their potential adverse effects on the environment and human health. In this study, two bionanocomposites prepared by immobilization of Bacillus subtilis esterase by crosslinking to halloysite and supported in chitosan and alginate beads were studied and proposed as a green approach. The esterase immobilization was confirmed by physical-chemical characterization. Bionanocomposite using chitosan showed the best degradation levels in batch tests attaining complete degradation of DBP and around 90% of DEHP. To determine the operational stability and efficiency of the system, two fixed bed reactors filled with both bionanocomposites were carried out operating in continuous mode. Chitosan based bionanocomposite showed the best performance being able to completely remove DBP and more than 85% of DEHP at the different flowrates. These results proved the potential of these synthesized bionanocomposites to effectively remove Phthalic Acid Esters.

Clinical utility and prognostic value of right atrial function in severe tricuspid regurgitation. One more piece of the puzzle

Background

Optimal management of severe tricuspid regurgitation (TR) remains controversial. While right ventricular systolic function is an established prognostic marker of outcomes, the potential role of right atrial (RA) function is unknown.

Purpose

This study was aimed to describe RA function by 2D speckle tracking echocardiography (STE) in severe TR and to evaluate its potential association with cardiovascular outcomes

Methods

Consecutive patients with at least severe TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic following a comprehensive clinical protocol were included. Consecutive control subjects and patients with permanent atrial fibrillation (AF) were included for comparison. RA function was measured with 2D-STE and 3 components of RA function were calculated: reservoir (RASr), conduit (RAScd) and contractile (RASct) RA values using an automatic 2D strain analytical software (AutoStrain, Philips Medical Systems the EPIQ system, Figure 1). A combined endpoint of hospital admission due to heart failure (HF) or all-cause mortality was defined. The interobserver variability of RA strain was assessed in 30 randomly selected subjects (20 TR+5 AF+5 controls).

Results

A total of 176 patients with severe TR, 20 AF patients and 20 controls subjects were included in this study. Patients with at least severe TR showed lower RASr and RAScd compared to controls and to AF patients (Figure 1 and Table 1, p<0.05). After a median follow-up of 28 months (IQR: 15–48 months), n=65 patients with severe TR (37%) reached the combined endpoint. 65 (37%) were admitted for right heart failure and 8% of the population (n=14) died. Patients with events showed lower values of RASr and RAScd (p<0.01 for both). Between both parameters RASr was more strongly associated with outcomes compared to RAScd (AUC 0.74 vs. 0.65, p<0.01). RASr was an independent predictor of heart failure and all cause mortality adjusted by additional imaging prognostic parameters in a multivariable analysis (biplane vena contracta, RV end-diastolic area, and RV-free wall longitudinal strain [LR χ2: 49.7, p<0.001]). RA area or volume was not associated with outcomes. A cut-off value of RASr of <9.4% held the best accuracy to predict outcomes (adjusted HR 3.2 (1.81–5.84), p<0.001, Figure 1). Inter-observer agreements for RA strain values across the whole cohort were high (intraclass correlation coefficient for RASr, RAScd and RASct, r=0.95, r=0.86, r=0,92 respectively)

Conclusions

Evaluation of RA function by 2D-STE is feasible, reproducible and is an independent predictor of heart failure and all-cause mortality in patients with at least severe TR.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): INSTITUTO CARLOS III

STREI: a new index of right heart function in isolated severe tricuspid regurgitation by Speckle tracking Echocardiography

Background

Right ventricular (RV) performance is key in the management of patients with severe tricuspid regurgitation (TR); detection of RV dysfunction is crucial to identify on time patients that benefit from valve intervention. Conventional parameters of RV function by 2D echocardiography are influenced by changes on preload conditions and can remain unaffected until late stages of the disease. The right atrium (RA) has an important role in modulating RV filling and RA performance is impaired in severe TR. Potentially, an index that combines RV and RA function may reflect a broader view of the effects of severe TR in right heart function.

Purpose

1) to evaluate the clinical utility of combining RV and RA strain for prediction of CV outcomes and 2) to design a novel index by Speckle-tracking echocardiography (STREI index) that integrates RA and RV information

Methods

Consecutive patients with at least severe TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic following a comprehensive clinical protocol were included. Consecutive control subjects and patients with permanent atrial fibrillation (AF) were included for comparison. Reservoir RA strain (RASr) and RV-free wall longitudinal strain (RV-FWLS) analysis were performed using novel, automated 2D strain analytical software (AutoStrain, Philips Medical Systems the EPIQ system, Figure 1). Novel STREI index was calculated with the formula: [2 × RV-FWLS] + RASr in absolute numbers.

A combined endpoint of hospital admission due to heart failure (HF) or all-cause mortality was defined. The interobserver variability of RA strain was assessed in 30 randomly selected subjects (20 TR+5 AF+5 controls).

Results

A total of 176 patients with severe TR, 20 AF patients and 20 controls subjects were included in this study. Patients with TR showed lower STREI values compared to controls and to AF patients (TR vs. controls vs. AF: 55±18 vs. 116±12 vs. 70±13, p<0,001). After a median follow-up of 28 months (IQR: 15–48 months), n=65 patients with severe TR (37%) reached the combined endpoint. Patients with both abnormal strains (abnormal RV-FWLS and abnormal RASr strain) showed a significantly higher rate of events (Figure 2A). In a multivariable analysis, STREI index was an independent predictor of HF and mortality adjusted by vena contracta, RV end-diastolic area, NYHA class and BNP values (LR χ2: 46,1, p<0,001). A cut off value of STREI index <50% held the best accuracy to predict outcomes. An abnormal STREI index was associated with 6,1-fold increased risk of HF or death (HR 6,9 (3,9–12,3), p<0,001, Figure 2B) Inter-observer agreements for STREI values were high (intraclass correlation coefficient = 0,96).

Conclusion

STREI index is a feasible and reproducible new parameter of RV performance that independently predicts outcomes in patients with severe TR. Randomized studies should confirm its potential to identify those patients that benefit from earlier valve interventions.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto Carlos III

Impact of previous cardiac conditions in prognosis and clinical management of patient with COVID-19 infection

Background

Recent studies suggest a higher mortality rate because of COVID-19 in patients with previous cardiac conditions compared to those without. Given the limited resources of intensive care units (ICU) during the pandemic outbreak, this fact has important implications.

Purpose

The main purpose of this study was to compare the 30-day mortality of the COVID-19 infection in patients with and without previous cardiac conditions. The secondary end point was to assess the differences in clinical severity of the infection (as development of Acute Respiratory Distress Syndrome – ARDS) and ICU admission amongst these patients.

Methods

A total of 1708 consecutive patients were prospectively included. The inclusion criteria were: a confirmed positive diagnosis of COVID-19 infection by PCR and being admitted to our centre between 18th and 23rd March 2020 and 22nd August and 9th January 2021. Patients were classified in two groups according to the presence of previous cardiac conditions (defined as previous history of myocardial infarction, heart failure and atrial fibrillation). Other comorbidities were extensively explored and Charlson Comorbidity Index was calculated. A propensity-score matching was performed and 145 patients with previous cardiac conditions were matched with 145 patients without.

Results

The group of patients with a previous cardiac condition included 421 patients (24.6%). The crude analysis showed a higher 30-day mortality rate among patients with previous cardiac affections (35.6% vs. 14.6%, p<0.001). They were also less likely to be admitted to the ICU (9.8% vs. 6.2%, p=0.022) and had a higher prevalence ARDS (48.9% vs. 33.9%, p<0.001). In the matched cohort, there were no significant differences between both groups regarding mortality (24.8% in the group of patients with previous cardiac conditions vs. 31.0%, p=0.272) nor ARDS prevalence (50.3% vs. 53.1%, p=0.655). There was a trend toward patients with previous cardiac conditions to be less likely to be admitted to the ICU (4.8% vs. 9.7%, p=0.090).

Conclusions

Patients with a personal history of previous cardiac conditions were less likely to be admitted to the ICU. However, our results show that when comparing cohorts with similar comorbidity burden, a previous cardiopathy “per se” does not significantly increase the risk of death in patients with a concomitant COVID infection.

Funding Acknowledgement

Type of funding sources: None. Mortality unmatched vs matched cohort

Prognostic value of serum biomarkers in patients with severe tricuspid regurgitation

Background

Significant tricuspid regurgitation (TR) is related to significant morbimortality. Given the lack of strong evidence, optimal timing for intervention remains controversial. Surgery is often performed late mainly because symptoms might go unnoticed until advance stages of the disease. The clinical impact of serum biomarkers evaluation in the serial evaluation of patients with significant TR is unknown.

Purpose

This study was aimed to evaluate the prognostic value of brain natriuretic peptide (BNP) and serum hepatic enzymes assessment in stable patients with significant tricuspid regurgitation

Methods

Consecutive patients in stable clinical status with significant TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic were included. Patients with previous episodes of heart failure were excluded. BNP levels and liver function enzymes were measured in all patients in their first visit. A combined endpoint of hospital admission due to right heart failure and cardiovascular (CV) mortality was defined.

Results

A total of 163 patients were included (mean age was 75±17 years, 69% females, 93% in NYHA I/II). According to etiology, 14% were primary TR and 86% were functional (49% due to corrected left valve disease and 37% due to tricuspid annulus dilatation). During a median follow up of 28 months (IQR: 15–49 months), n=59 patients (36%) reached the combined endpoint (n=12 patients died). Differences in BNP and liver function enzymes values in patients with or without events are shown in figure 1. BNP values and both cholestasis enzymes (alkaline phosphatase and gamma-glutamyl transferase) were independent predictors of the combined endpoints (Figure 2). In a multivariable Cox analysis (forward selection) in a model including BNP, alkaline phosphatase and gamma-glutamyl transferase, alkaline phosphatase remained as the sole independent predictor of outcome (HR: 1.01, [1.004–1.014], p<0.001).

Conclusion

Serum biomarkers held prognostic value in patients with significant TR. BNP values and colestasis enzymes are predictive of heart failure and CV death in stable patients with TR. Given the low clinical expression of the disease, these serum biomarkers should be considered in the serial evaluation of these patients.

Funding Acknowledgement

Type of funding sources: None. Comparison of serum biomarkersCox regression analysis

Removal of polyvinylamine sulfonate anthrapyridone dye by application of heterogeneous electro-Fenton process

Diversity and rapidly multiplication of the pollutants incite as to improve the conventional treatments wastewater methods. One of the bottlenecks often faced is the presence into wastewater of organic pollutants with complex structures that requests the design of efficient processes. Thus, this work investigates the removal of polyvinylamine sulfonate anthrapyridone (PSA) dye which complex structure makes difficult its degradation by conventional technologies. For that, a heterogeneous oxidative process using pyrite as sustainable catalyst was designed. Initially, the performance of the system BBD-carbon felt as anode and cathode, respectively for the production of H₂O₂ was determined in comparison with system boron-doped diamond nickel foam. The carbon felt electrode provided the highest oxidant production, and it was selected for the treatment of the polymeric dye. Several oxidative processes were evaluated, and the best degradation levels were obtained by application of electro-Fenton-pyrite process. In addition, it was determined that dye removal followed a kinetic model of pseudo-first-order achieving the highest efficiency by operation at optimum dosage of pyrite 2 g/L and 200 mA of current intensity. Depending on the optimal experimental conditions, these values lead to a nearly complete mineralization (total organic carbon removal of 95%) after 6 h. Furthermore, the reusability of pyrite was evaluated, by removal of PSA in four cycles.

Influence of operational parameters on electro-Fenton degradation of organic pollutants from soil

The combination of the Fenton's reagent with electrochemistry (the electro-Fenton process) represents an efficient method for wastewater treatment. This study describes the use of this process to clean soil or clay contaminated by organic compounds. Model soil of kaolinite clay polluted with the dye Lissamine Green B (LGB) was used to evaluate the capability of the electro-Fenton process. The effects of operating parameters such as electrode material and dye concentration were investigated. Operating in an electrochemical cell under optimized conditions while using electrodes of graphite, a constant potential difference of 5 V, pH 3, 0.2 mM FeSO(4). 7H(2)O, and electrolyte 0.1 M Na(2)SO(4), around 80% of the LGB dye on kaolinite clay was decolorized after 3 hours with an electric power consumption around 0.15 W h g(-1). Furthermore, the efficiency of this process for the remediation of a real soil polluted with phenanthrene, a typical polycyclic aromatic hydrocarbon, has been demonstrated.

Removal of organic pollutants and heavy metals in soils by electrokinetic remediation

In this work, the feasibility of electrokinetic remediation for the restoration of polluted soil with organic and inorganic compounds had been development and evaluated using a model soil sample. The model soil was prepared with kaolinite clay artificially polluted in the laboratory with chromium and an azo dye: Reactive Black 5 (RB5). The electromigration of Cr in a spiked kaolinite sample was studied in alkaline conditions. Despite of the high pH registered in the kaolinite sample (around pH 9.5), Cr migrated towards the cathode and it was accumulated in the cathode chamber forming a white precipitate. The removal was not complete, and 23% of the initial Cr was retained into the kaolinite sample close to the cathode side. The azo dye RB5 could be effectively removed from kaolinite by electrokinetics and the complete cleanup of the kaolinite could be achieved in alkaline environment. In this condition, RB5 formed an anion that migrated towards the anode where it was accumulated and quickly degraded upon the electrode surface. The electrokinetic treatment of a kaolinite sample polluted with both Cr and RB5 yielded very good results. The removal of Cr was improved compared to the experiment where Cr was the only pollutant, and RB5 reached a removal as high as 95%. RB5 was removed by electromigration towards the anode, where the dye was degraded upon the surface of the electrode by electrochemical oxidation. Cr was transported towards the cathode by electromigration and electroosmosis. It is supposed that the interaction among RB5 and Cr into the kaolinite sample prevented premature precipitation and allow Cr to migrate and concentrate in the cathode chamber.

Electromigration of Mn, Fe, Cu and Zn with citric acid in contaminated clay

Metal reactivity, speciation and solubility have an important influence in its transportation through a porous matrix by electrokinetics and, therefore, they dramatically affect the removal efficiency. This work deals with the effect of solubility and transport competition among several metals (Mn, Fe, Cu and Zn) during their transport through polluted clay. The unenhancement electrokinetic treatment results in a limited removal of the tested metals because they were retained into the kaolinite sample by the penetration of the alkaline front. Metals showed a removal degree in accordance with the solubility of the corresponding hydroxide and its formation pH. In 7 days of treatment, the removal results were: 75.6% of Mn; 68.5% of Zn, 40.6% of Cu and 14.8% of Fe. In order to avoid the negative effects of the basic front generated at the cathode, two different techniques were proposed and tested: the addition of citric acid as complexing agent to the polluted kaolinite sample and the use of citric acid to control de pH on the cathode chamber. Both techniques are based on the capability of citric acid to act as a complexing and neutralizing agent. Almost complete removal of Mn, Cu and Zn was achieved when citric acid was used (as neutralizing or complexing agent). But Fe only reached 33% of removal because it formed a negatively charged complex with citrate that retarded its transportation to the cathode.

Remediation of phenanthrene from contaminated kaolinite by electroremediation-Fenton technology

Polycyclic aromatic hydrocarbons (PAHs) cause a high environmental impact when released into the environment. The objective of this study was to evaluate the capacity to decontaminate polluted soils with phenanthrene as a model PAH using a combination of two technologies: electrokinetic remediation and Fenton process. Kaolinite was used as a model sample that was artificially polluted at the laboratory at an initial concentration of phenanthrene of 500 mg kg(-1) of dried kaolinite. The standard electrokinetic process resulted in negligible removal of phenanthrene from the kaolinite sample. Faster and more efficient degradation of this compound can be promoted by introduction of a strong oxidant into the soil such as hydroxyl radicals. For this reason, the Fenton reactions have been induced in several experiments in which H(2)O(2) (10%) was used as flushing solution, and kaolinite polluted with iron was used. When anode and cathode chambers were filled with H(2)O(2) (10%), the kaolinite pH is maintained at an acid value around 3.5 without pH control and an overall removal and destruction efficiency of phenanthrene of 99% was obtained in 14 days by applying a voltage gradient of 3 V cm(-1). Therefore, it is evident that a combined technology of electrokinetic remediation and Fenton reaction is capable of simultaneously removing and degrading of PAHs in polluted model samples with kaolinite.