Secondary hyperparathyroidism is associated with higher mortality in men with moderate to severe chronic kidney disease

Secondary hyperparathyroidism is associated with mortality in patients undergoing maintenance dialysis treatment. We studied 515 male US veterans with chronic kidney disease, who were not yet on dialysis, to see what outcomes were associated with secondary hyperparathyroidism in this population. Relationships between intact parathyroid hormone levels and all-cause mortality along with the composite of mortality or incidence of dialysis were measured in unadjusted and adjusted Cox models for case-mix and laboratory variables. Elevated parathyroid hormone levels above the upper limit compared to the lower limit of the normal range were significantly associated with mortality after adjustments. Higher intact parathyroid hormone levels in the upper limit of normal were significantly associated with higher mortality overall and showed similar trends in subgroups of patients with stage 3 and stage 4-5 chronic kidney disease and with higher and lower serum calcium and phosphorus levels. Similar associations were found with the composite outcome of mortality or dialysis. Our study shows that secondary hyperparathyroidism is independently associated with higher mortality in patients with chronic kidney disease but not yet on dialysis.

Potentiometric sensor for iron (III) quantitative determination: experimental and computational approaches

The current work deals with fabrication and validation of a new highly Fe³⁺ selective sensor based on benzo-18-crown-6 (b-18C6) using the potentiometric method. The proposed sensor revealed satisfactory performance for quantitative evaluation of Fe³⁺ trace amount in environmental samples. The ratio of membrane ingredients optimized and the membrane with the composition of 4:30:65.5:0.5 mg of b-18C6:PVC:o-NPOE:KTpClPB exhibited the desirable Nernstian slope of 19.51 ± 0.10 (mV per decade of activity) over the pH range from 2.5 to 5.7 with an acceptable dynamic concentration range of 1.0 × 10^-6 M to 1.0 × 10^-1 M and lower detection limit of 8.0 × 10^-7 M. The proposed sensor demonstrated an appropriate reproducibility with a rapid response time of 12 s and the suitable lifetime of 10 weeks. To validate the accurate response of the proposed sensor, AAS technique applied for the determination of Fe³⁺ in real aqueous mediums such as drinking tap water and hospital wastewater sample after treatment by electrocoagulation process. Theoretical studies carried out using DFT/B3LYP computational level with 6-311G basis set to optimize the adsorption sites of Fe⁺³ cationic species by b-18C6. The obtained adsorption energy with large negative value confirmed the formation of a stable complex.

Cesium selective polymeric membrane sensor based on p-isopropylcalix[6]arene and its application in environmental samples

The present work deals with developing a highly selective membrane electrode based on p-isopropylcalix[6]arene for accurate determination of trace amounts of cesium cations.

Immobilization of tris(2 pyridyl) methylamine in a PVC-Membrane Sensor and Characterization of the Membrane Properties

Background

Due to the increasing industrial use of titanium compounds, its determination is the subject of considerable efforts. The ionophore or membrane active recognition is the most important component of any polymeric membrane sensor. The sensor’s response depends on the ionophore and bonding between the ionophore and the target ion. Ionophores with molecule-sized dimensions containing cavities or semi-cavities can surround the target ion. The bond between the ionophore and target ion gives different selectivity and sensitivity toward the other ions. Therefore, ionophores with different binding strengths can be used in the sensor.

Results

In the present work, poly (vinyl chloride) (PVC) based membrane incorporating tris (2 pyridyl) methylamine (tpm) as an ionophore has been prepared and explored as a titanium(III) selective sensor.

Conclusions

The strengths of the ion–ionophore (Ti(OH)²⁺-tpm) interactions and the role of ionophore on membrane were tested by various techniques such as elemental analysis, UV–vis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD). All data approved the successful incorporation of organic group via covalent bond.

Thermodynamic study of the complexation of p-isopropylcalix[6]arene with Cs+ cation in dimethylsulfoxide-acetonitrile binary media

The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide-acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log K(f) of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°(c) and DS°(c)) for formation of (p-isopropyl-calix[6]arene·Cs)+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs)+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.

Delayed death following paraquat poisoning: three case reports and a literature review

Paraquat (PQ) poisoning is principally reported in developing countries. However, most fatalities occur elsewhere due to the induction of multi-organ failure. PQ poisoning can hardly be managed by clinical practice, and no specific antidote has come into existence yet. Here three cases, including 17-, 20-, and 23-year-old men, who were poisoned with PQ, have been reported. Furthermore, the literature regarding biological mechanisms, clinical manifestation, and treatment of PQ-induced toxicity was reviewed. Patients who, either intentionally or accidentally, ingested PQ earlier were initially found to be stable at the emergency department (ED). Therefore, they were discharged from the hospital under a follow-up. However, after several days, the patients were referred to the hospital for the second time and despite cardiovascular resuscitation (CPR) efforts, they suddenly expired. The delayed death following exposure to PQ was reported for inducing gradual progressive pulmonary fibrosis, metabolic acidosis, neurotoxicity, renal failure, and liver injury in poisoned patients. Therefore, PQ-intoxicated patients should be supervised for up to several weeks, and kept in the hospital for a longer period of time. Clinical manifestations and laboratory findings are beneficial markers that act as useful predictors of PQ poisoning.

Adsorption of tetracycline antibiotic onto modified zeolite: Experimental investigation and modeling

Artificial Neural Networks (ANNs) model and Adaptive Neuro-Fuzzy Inference System (ANFIS) were used to estimate and predict the removal efficiency of tetracycline (TC) using the adsorption process from aqueous solutions. The obtained results demonstrated that the optimum condition for removal efficiency of TC were 1.5 g L⁻¹ modified zeolite (MZ), pH of 8.0, initial TC concentration of 10.0 mg L⁻¹, and reaction time of 60 min. Among the different back-propagation algorithms, the Marquardt–Levenberg learning algorithm was selected for ANN Model. The log sigmoid transfer function (log sig) at the hidden layer with ten neurons in the first layer and a linear transfer function were used for prediction of the removal efficiency. Accordingly, a correlation coefficient, mean square error, and absolute error percentage of 0.9331, 0.0017, and 0.56% were obtained for the total dataset, respectively. The results revealed that the ANN has great performance in predicting the removal efficiency of TC.•

ANNs used to estimate and predict tetracycline antibiotic removal using the adsorption process from aqueous solutions.

•

The model's predictive performance evaluated by MSE, MAPE, and R².

Titanium (III) cation selective electrode based on synthesized tris(2pyridyl) methylamine ionophore and its application in water samples

The introduction of low detection limit ion selective electrodes (ISEs) may well pave the way for the determination of trace targets of cationic compounds. This research focuses on the detection of titanium (III) cation using a new PVC-membrane sensor based on synthesized tris(2pyridyl) methylamine (tpm) ionophore. The application and validation of the proposed sensor was done using potentiometric titration, inductively coupled plasma atomic emission spectrometry (ICP-AES), and atomic absorption spectrometry (AAS). The membrane sensor exhibited a Nernstian response to the titanium (III) cation over a concentration range of 1.0 × 10⁻⁶–1.0 × 10⁻² M and pH range from 1–2.5. The Nernstian slope, the lower of detection (LOD), and the response time (t_95%) of the proposed sensor were 29.17 ± 0.24 mV/dec, 7.9 × 10−7 M, and 20 s, respectively. The direct determination of 4–39 μg/ml of titanium (III) standard solution showed an average recovery of 94.60 and a mean relative standard deviation of 1.8 at 100.0 μg/ml. Finally, the utilization of the electrodes as end-point indicators for potentiometric titration with EDTA solutions for titanium (III) sensor was successfully carried out.

A rapid and efficient removal approach for degradation of metformin in pharmaceutical wastewater using electro-Fenton process; optimization by response surface methodology

Presence of emerging contaminants such as pharmaceutical products in aquatic environments has received high concern due to their undesirable effect on wildlife and human health. Current work deals with developing a treatment model based on the electro- Fenton (EF) process for efficient removal of metformin (MET) from an aqueous medium. The obtained experimental results revealed that over the reaction time of 10 min and solution pH of 3, the maximum removal efficiency of 98.57% is achieved where the value of MET initial concentration, current density, and H₂O₂ dosage is set at 10 mg.L^-1, 6 mA.cm^-2, and 250 μL.L^-1, respectively, which is in satisfactory agreement with the predicted removal efficiency of 98.6% with the desirability of 0.99. The presence of radical scavengers throughout the mineralization of MET under the EF process revealed that the generation of ^•OH radicals, as the main oxidative species, controlled the degradation mechanism. The obtained kinetics data best fitted to the first order kinetic model with the rate constant of 0.4224 min^-1 (R² = 0.9940). The developed treatment process under response surface methodology (RSM) was employed for modeling the obtained experimental data and successfully applied for efficient removal of the MET contaminant from pharmaceutical wastewater as an adequate and cost-effective approach.

Electro-Fenton approach in oxidative degradation of dimethyl phthalate - The treatment of aqueous leachate from landfills

Herein, the dimethyl phthalate (DMP) contamination, as an emerging pollutant, has been cost-effectively removed from landfill leachate through an advanced oxidation process, that is the electro-Fenton (EF) process. For this purpose, a quadratic polynomial model was developed via response surface methodology (RSM). Furthermore, the analysis of variance (ANOVA) was performed for evaluating the significance of the proposed assumptions. The actual removal rate of 99.1% was obtained with optimal values of 4 mg L^-1 of initial DMP concentration, 50 mM Na₂SO₄, 600 μL L^-1 H₂O₂, 8-minute electrolytic time, solution pH 3 and 6 mA cm^-2 current density for the process variables and was consistent with the expected 99.6% removal rate. Satisfactory correlation coefficients were obtained, and a non-significant value of 0.0618 for model mismatch confirmed that the proposed model is extremely important and can successfully predict the effectiveness of DMP removal. The kinetics of the process and the effect of the presence of some radical scavengers were studied to understand the exact mechanism of DMP degradation. Therefore, it was observed that the reaction of hydroxyl radicals with DMPs followed the first-order kinetics model. Moreover, it was established that the optimal ratio of H₂O₂/Fe²⁺ mole was 1.6 and the electricity consumption was 0.157 kWh m^-3. The elaborated treatment model used to remove DMP from landfill leachate showed that DMP contamination was effectively removed with a 95.6% removal efficiency in the investigating process.

In situ generation of hydroxyl radical for efficient degradation of 2,4-dichlorophenol from aqueous solutions

Since 2,4-dichlorophenol (2,4-DCP) as a priority pollutant is used in numerous industrial processes, its removal from the aqueous environment is of utmost importance and desire. Herein, the authors describe an electrochemical treatment process for efficient removal of 2,4-DCP from aqueous solutions using electro-Fenton (EF) process. Response surface methodology (RSM) was applied to optimize the operating parameters. Analysis of variance (ANOVA) confirmed the significance of the predicted model. The effect of independent variables on the removal of 2,4-DCP was investigated and the best removal efficiency of 98.28% achieved under the optimal experimental condition including initial pH of 3, H₂O₂ dosage of 80 μL, initial 2,4-DCP concentration of 3.25 mg L^-1, current density of 3.32 mA cm^-2, and inter-electrode distance of 5.04 cm. The predicted removal efficiency was in satisfactory agreement with the obtained experimental removal efficiency of 99.21%. According to the obtained polynomial model, H₂O₂ dosage revealed the most significant effect on degradation process. The kinetic investigation revealed that the first-order model with the correlation coefficient of 0.9907 and rate constant (K_app) of 0.831 min^-1 best fitted with the experimental results. Generation of the hydroxyl radicals throughout the EF process controlled the degradation process.

Iron-modified activated carbon derived from agro-waste for enhanced dye removal from aqueous solutions

Background and aim

Finding a cost-effective adsorbent can be an obstacle to large-scale applications of adsorption. This study used an efficient activated carbon adsorbent based on agro-waste for dye removal.

Methods

Pistachio shells as abundant local agro-wastes were used to prepare activated carbon. Then, it was modified with iron to improve its characteristics. Acid red 14 was used as a model dye in various conditions of adsorption (AR14 concentration 20–150 mg L⁻¹, pH 3–10, adsorbent dosage 0.1–0.3 g L⁻¹, and contact time 5–60 min).

Results

A mesoporous adsorbent was prepared from pistachio shells with 811.57 m² g⁻¹ surface area and 0.654 cm³ g⁻¹ pore volume. Iron modification enhanced the characteristics of activated carbon (surface area by 33.3% and pore volume by 64.1%). Adsorption experiments showed the high effectiveness of iron-modified activated carbon for AR14 removal (>99%, >516 mg g⁻¹). The adsorption followed the pseudo-second kinetic model (k = 0.0005 g mg⁻¹ min⁻¹) and the Freundlich isotherm model (K_f = 152.87, n = 4.61). Besides, the reaction occurred spontaneously (ΔG⁰ = −36.65 to −41.12 kJ mol⁻¹) and was exothermic (ΔH⁰ = −41.86 kJ mol⁻¹ and ΔS⁰ = −3.34 J mol⁻¹ K⁻¹).

Conclusion

Iron-modified activated carbon derived from pistachio shells could be cost-effective for the treatment of industrial wastewater containing dyes.

Electrochemical treatment of pharmaceutical wastewater through electrosynthesis of iron hydroxides for practical removal of metronidazole

Antibiotics as the severe contaminants of aqueous environments were received growing attention during the last decades. The current work is the first report on investigating the potency and efficiency of electrocoagulation process in the successful removal of metronidazole (MNZ) from pharmaceutical wastewater using response surface methodology based on central composite design. The applied method by optimizing the independent and combined effects of significant variables which affecting the EC process enhanced the removal efficiency of MNZ. Analysis of variance was applied to verify the significance of independent variables solely and their interactions. The best removal efficiency of 100% found under the optimal operating condition of initial MNZ concentration 21.6 mg L^-1, pH 8.2, current density 6.0 mA cm^-2, inter-electrode distance 3 cm, and reaction time of 14.6 min. Isotherm investigations revealed that the Langmuir model with the R² of 0.994 best fitted to the obtained experimental equilibrium results. The fast adsorption of MNZ on the surface of Fe(OH)₃ and [Fe(OH)₂]⁺ with the equilibrium time of 15 min confirmed that the kinetics of the electrocoagulation process follow the pseudo-second-order model (R² = 0.962). The electrocoagulation process under the optimal operating condition revealed that the electrical energy consumption per each m³ of treated pharmaceutical wastewater, per each g of MNZ, removed, and per each kg of Fe electrode consumed, were found to be 0.516 kWh m^-3, 0.0234 kWh g^-1, and 0.0436 kWh kg^-1, respectively.

Response surface modeling of ceftriaxone removal from hospital wastewater

In recent decades, an emerging concern of widespread antimicrobial resistance has been raised due to the existence of pharmaceutical samples such as antibiotics in an aqueous medium. Herein, antibiotic ceftriaxone (CTX) removal from hospital wastewater employing a hybrid process of electrocoagulation (EC) and adsorption (AD) was investigated. The response surface methodology (RSM) was employed to study the influences of main operating variables, including initial CTX concentration, pH, current density, reaction time, and chitosan dosage, on the removal efficiency of the treatment process. Under the optimum condition of the employed EC/AD hybrid treatment process, where initial CTX concentration, pH solution, the current density, adsorbent dosage, and reaction time were set at 20.0 mg L^-1, 7.5, 6.0 mA cm^-2, 0.75 g L^-1, and 12.5 min, respectively, the removal efficiency of 100% was achieved. Analysis of variance (ANOVA) confirmed that the developed quadratic treatment model is highly significant. The applied EC/AD hybrid treatment process revealed the electrical energy consumption of 0.84 kWh m^-3 and 0.2168 kWh (g Al)^-1 per cubic meter of hospital wastewater and gram of consumed aluminum electrode, respectively. The second-order kinetic model with R² of 0.9514 and the Langmuir isotherm model with R² of 0.973 best fit the developed EC/AD hybrid treatment process, and q_m was found to be 111.1 mg g^-1. The obtained experimental results confirmed that the CTX concentration of the hospital wastewater was reduced to zero after applying the EC/AD hybrid process.

Simultaneous electrochemical degradation of pesticides from the aqueous environment using Ti/SnO2-Sb2O3/PbO2/Bi electrode; process modeling and mechanism insight

In this work, modified Bi-PbO₂ electrode was fabricated and employed for simultaneous degradation of fenitrothion (FT), trifluralin (TF), and chlorothalonil (CT) from synthetic and pesticide wastewater through the anodic oxidation process. A novel high-performance liquid chromatography method was developed and optimized to identify the pesticides simultaneously. Quadratic models were developed to investigate the effects of main operating parameters and predict the degradation efficiencies of the treatment processes. The R² of the degradation efficiencies were obtained of 0.9847, 0.9910, and 0.9821 for FT, TF, and CT, respectively, which indicates the degree of conformity between the experimental and the actual values of degradation efficiencies, and the adjusted R² values for the degradation efficiency of FT, TF, and CT in proposed models were 0.9826, 0.9898, and 0.9796, and the values of the predicted R² were 0.9792, 0.9875, and 0.9755, respectively. The maximum degradation efficiencies of 99.7, 100, and 100% obtained for FT, TF, and CT, respectively, under the optimal operating condition of FT, TF, and CT concentration of 10.0, 6.0, and 8.0 mg L^-1, respectively, pH 6.0, the current density 6.0 mA cm^-2, and electrolysis time of 60 min. Chemical oxygen demand removal and energy consumption were 64.7% and 5.1 kWh m^-3. Eventually, the generated intermediates and other produced species of pesticides through the treatment process was evaluated using a gas chromatography-mass spectrometry method, and their degradation pathways were proposed.

Microniosomes for concurrent doxorubicin and iron oxide nanoparticles loading; preparation, characterization and cytotoxicity studies

The current work deals with developing a suitable drug delivery system of doxorubicin (DOX) for intraperitoneal chemotherapy using niosomes through formulating non-ionic surfactants consisting of Brij™ 52, span™ 60 and Solulan™ C24. Entrapping the magnetite nanoparticles in the hydrophilic parts of niosomes was accompanied with high-efficient DOX loading by the current novel remote-loading method. Cytotoxicity of the prepared formulations was evaluated in vitro against A549 and PC-12 cell lines using the colorimetric WST-1 assay test. The obtained results revealed that, the cytotoxicity of DOX increased up to 22% especially on A549 cells by the current delivery system.