Functionalized Carbon Nanotubes Encapsulated Alginate Beads for the Removal of Mercury Ions: Design, Synthesis, Density Functional Theory Calculation, and Demonstration in a Batch and Fixed-Bed Process.

Various nanomaterials have been envisaged mainly through batch studies for environmental remediation application. The real utilization of these new generation adsorbents in large scale pose a difficulty due to its low density and small size which makes it difficult for isolation after application. In this context, nanoadsorbents polymer composite beads can be seen as a way out. Here, functionalized CNTs (carbon nanotubes) have been fabricated into micro beads with sodium alginate. The alginate-functionalized CNT (Alg-f-CNT) beads were then comprehensively evaluated for batch and fixed-bed column separation of divalent mercury ions from an aqueous medium. The effects of process parameters such as pH, contact time, feed Hg2+ concentration, and temperature were studied. Simulation of the experimental data suggested that adsorption is an endothermic spontaneous process which follows the pseudo-second-order kinetic and Langmuir isotherm model. The desorption of the Hg2+ ion from used adsorbent was possible with 1 M HNO3. The breakthrough curves at different process parameters were investigated during fixed-bed column separation and found to be in good agreement with Thomas model. The regeneration and reusability of the adsorbent were tested up to five cycles without a significant decrease in the removal performance. Density functional theory studies revealed stronger interaction of Alg-f-CNT with Hg compared to free alginic acid and established the role of carboxyl and oxo groups present in the adsorbent in the coordination of the Hg2+ ions. The experimental results demonstrate that functionalized CNT-encapsulated alginate beads are a promising alternate material, which can be used to remove mercury in the fixed-bed column mode of the operation.

Efficient Removal of Uranyl Ions Using PAMAM Dendrimer: Simulation and Experiment.

In this work, using atomistic molecular dynamics (MD) simulations and polymer-assisted ultrafiltration experiments, we explore the adsorption and removal of uranyl ions from aqueous solutions using poly(amidoamine) (PAMAM) dendrimers. The effects of uranyl ion concentration and the pH of the solution were examined for PAMAM dendrimers of generations 3, 4, and 5. Our simulation results show that PAMAM has a high adsorption capacity for the uranyl ions. The adsorption capacity increases with increasing concentration of uranyl ions for all 3 generations of PAMAM in agreement with experimental findings. We find that the number of uranyl ions bound to PAMAM is significantly higher in acidic solutions (pH < 3) as compared to neutral solutions (pH ∼ 7) for all uranyl ion concentrations. Additionally, we find an increase in the number of adsorbed uranyl ions to PAMAM with the increase in the dendrimer generation. This increase is due to the greater number of binding sites present for higher-generation PAMAM dendrimers. Our simulation study shows that nitrate ions form a solvation shell around uranyl ions, which allows them to bind to PAMAM binding sites, including the amide, amine, and carbonyl groups. In polymer-assisted ultrafiltration (PAUF) experiments, the removal percentage of uranyl ions by G3 PAMAM dendrimer increased from 36.3% to 42.6% as the metal ion concentration increased from 2.1 × 10-5 M to 10.5 × 10-5 M at a pH of 2. Our combined experiment and simulation study suggests that PAMAM is an effective adsorbent for removing uranyl ions from aqueous solutions.

Fixed-dose combination of three drugs, i.e. LABA/LAMA/ICS for COPD: Results of a real-world study from India.

BACKGROUND: The use of triple therapy with inhaled corticosteroids, long-acting beta-agonist and long-acting antimuscarinics has been shown to be beneficial in COPD patients who continue to have symptoms and exacerbations, despite receiving dual bronchodilator combinations. This study assessed the real-world effectiveness and safety of once-daily, fixed-dose combination of Tiotropium/Formoterol/Ciclesonide (TFC) (18 mcg/12 mcg/400 mcg) via dry powder inhaler (DPI) or metered dose inhaler (MDI) in patients with COPD. PATIENTS AND METHODS: In this 24-week, open-label, prospective, non-comparative, multicentre, real-world study, COPD patients requiring triple therapy as judged by their physician, were enrolled. The primary endpoint was mean change from baseline in pre-dose Forced Expiratory Volume in 1 s (FEV1) at week 24. Pre and post-dose (30 min) FEV1, Forced Vital capacity (FVC), COPD Assessment Test (CAT), modified Medical Research Council (mMRC) score and safety were also evaluated. A post-hoc analysis was conducted to evaluate the efficacy of the triple drug combination among smoker and non-smoker COPD patients. RESULTS: Out of the 297 patients enrolled [mean age 61 ± 10 years; 84.8% males; 55.2% smokers and post-dose FEV1 (% predicted) 39 ± 16%], 253 completed the study. Mean change in pre-dose FEV1 from baseline to week 24 increased significantly after administering the triple drug combination [580 ± 600 mL, 95% CI (510, 650 mL), p < 0.0001]. The increase in the pre-dose FEV1 was significant at all time points (p < 0.0001). Similar improvements were seen in pre-dose FVC, post-dose FEV1 and post-dose FVC across all time points. CAT scores and the proportion of patients with improved mMRC score improved at all visits. The post-hoc analysis showed that TFC significantly increased pre-dose FEV1 both among smokers [mean change 200 ± 430 mL, 95% CI (130, 270 mL), p < 0.0001] as well as non-smokers [990 ± 470 mL, 95% CI (900, 1070 mL), p < 0.0001] at week 24. This difference was significant from week 12 onwards. Mean change in pre and post-dose FEV1 and FVC was significant across all visits between the two groups. At week 24, CAT score reduced significantly from baseline (overall: -6.6 ± 6.07; smokers: -5.17 + 6.96; non-smokers: 8.06 ± 4.44; all p < 0.0001). The mean difference between the two groups was 2.88 (p < 0.0001) at week 24. TFC was well tolerated. CONCLUSION: In this real world, multicentre study in India, TFC significantly improved lung function, symptoms and quality of life among all patients with COPD, but the effect was more pronounced among non-smoker COPD patients.

Device-handling study of a novel breath-actuated inhaler, Synchrobreathe®, versus a pMDI.

INTRODUCTION: Synchrobreathe®, a new-generation, novel breath-actuated inhaler (BAI) can address the key issues arising during the use of both pressurised metered dose inhalers ([pMDIs]; hand-breath coordination) and dry powder inhalers ([DPIs]; high inspiratory flow required) with respect to optimal drug deposition. MATERIALS AND METHODS: This was an open-label, prospective, 2-week, multicentre study that assessed device handling, ease of use, errors and participant perception regarding the use of Synchrobreathe® versus a pMDI in patients with chronic obstructive pulmonary disease (COPD) (n = 162) or asthma (n = 239) and inhaler-naïve healthy volunteers (n = 59). Ability to use the device without errors at the first attempt, total number of errors before and after training, time taken to use the device correctly and total number of training sessions, and number of attempts to perform the correct technique on Day 1 and Day 14 were evaluated. Device handling and preference questionnaires were also administered on Day 14. RESULTS: Of 460 participants, 421 completed the study. The number of participants using Synchrobreathe without any error after reading the patient information leaflet (PIL) was significantly low (p < 0.05) on Day 1. On Day 14, significantly more number of participants used Synchrobreathe without any error (p < 0.001). The total number of errors before and after training with Synchrobreathe was significantly less (p < 0.001). The average time required to perform the inhalation technique correctly (p < 0.01) and the total number of attempts (P < 0.001) with Synchrobreathe were significantly lower. The average number of attempts to inhale correctly was significantly (p < 0.001) less with Synchrobreathe on Day1 and Day 14. Most participants rated Synchrobreathe as their choice of inhaler. CONCLUSION: Synchrobreathe is an easy-to-use and easy-to-handle device with significantly less number of errors, which may have positive implications for disease control in asthma and COPD.

A Multicentre, Open label, Randomized, Comparative, Parallel Group, Active-controlled, Phase III Clinical Trial to Evaluate Safety and Efficacy of Arbekacin Sulphate Injection versus Vancomycin Injection in Patients Diagnosed with MRSA Infection.

BACKGROUND: Increasing resistance to currently available antimicrobials has led to the development of new agents. Arbekacin is aminoglycoside antibiotic currently used in Japan and Korea for the treatment of infections caused by multi-resistant bacteria including MRSA. Currently there is no published data available for use of Arbekacin in Indian patient population, thus the present study was conducted to evaluate the safety and efficacy of Arbekacin in Indian population. MATERIAL AND METHODS: The study was a phase III, multi-centre, open-label, randomised comparative, active control study. Subjects with microbiologically confirmed MRSA infection were randomized in the study to receive either Arbekacin sulphate 200 mg OD or Vancomycin hydrochloride 1000 mg BD for a period of 7 to 14 days. The primary endpoint was to evaluate the overall cure rate i.e. Clinical and microbiological cure during the study. RESULTS: A total of 162 patients were randomized in 2 treatment groups (i.e. 81 patients in each group). Out of these microbiologically confirmed MRSA patients, 153 patients were admitted for SSTI while 9 patients were admitted for CAP. Overall cure rate of MRSA infection (clinical as well as microbiological cure) was comparable in both the treatment groups i.e. 97.5% (79/81) in Arbekacin group and 100 % (79/79) in Vancomycin group (p value: 0.159). Both Arbekacin and Vancomycin were well tolerated by the patients during the study period. CONCLUSION: Arbekacin can be considered as safe and effective alternative to vancomycin in the management of MRSA infections.

Interfacial Behavior of Cs+, K+, Na+, and Rb+ Extraction in the Presence of Dibenzo-18-Crown-6 from the Nitrobenzene-Water Biphasic System: Experimental, Quantum Chemical, and Molecular Dynamic Studies.

Extraction of metal ions (i.e., Cs+, K+, Na+, and Rb+) in the presence of ionophore such as dibenzo-18-crown-6 (DB18C6) from the nitrobenzene-water biphasic system is reported by COSMO-RS (conductor-like screening model for real solvents) predictions, molecular dynamics simulation, along with experimental validation. The predicted values of selectivity as obtained for the Na+-DB18C6 complex were 4.571, 4.877, and 4.947 at 298.15, 308.15, and 318.15 K, respectively. This was then confirmed by the experimental distribution coefficient (D) as obtained in the diluent systems along with by varying the metal ion to crown ether ligand (M-L) mole ratios: 10:1 (0.1 M M+ and 0.01 M DB18C6), 1:1 (0.01 M M+ and 0.01 M DB18C6), and 1:10 (0.001 M M+ and 0.01 M DB18C6). The experimentally determined values of D Na (i.e., 0.059, 0.060, and 0.056) were found to be very large as compared to the values of D Cs (i.e., 0.001, 0.010, and 0.024) in the nitrobenzene phase. It indicates an excellent extraction ability of DB18C6 for Na+. The rate of phase separation for the Cs+NO3 - system was slow as compared to other metal ion systems. The binding energies, free energies, and nonbonded interaction energies of the complexed metal ion in solution were calculated with both explicit and implicit solvent models. A higher interaction energy between Na+-DB18C6 complex and nitrobenzene was observed (i.e., -289.92 in the explicit model and -143.12 kcal/mol in the implicit model) when compared with other metal ions (i.e., Cs+, K+, and Rb+).

Adsorption of uranium from aqueous solution by PAMAM dendron functionalized styrene divinylbenzene.

A new polymeric chelating resin was prepared by growing third generation poly(amido)amine (PAMAMG3) dendron on the surface of styrene divinylbenzene (SDB) and characterized by FTIR, TGA and SEM. The ideal branching of dendron in the chelating resin was determined from potentiometric titration. Adsorption of uranium (VI) from aqueous solution using PAMAMG3-SDB chelating resin was studied in a series of batch experiments. Effect of contact time, pH, ionic strength, adsorbent dose, initial U(VI) concentration, dendron generation and temperature on adsorption of U(VI) were investigated. Kinetic experiments showed that U(VI) adsorption on PAMAMG3-SDB followed pseudo-second-order kinetics model appropriately and equilibrium data agreed well with the Langmuir isotherm model. Thermodynamic parameters (ΔH°, ΔS°, ΔG°) were evaluated from temperature dependent adsorption data and the uranium adsorption on PAMAMG3-SDB was found to be endothermic and spontaneous in nature. The sticking probability value (5.303 × 10(-9)), kinetic and isotherm data reveal the chemisorption of uranium on PAMAMG3-SDB and adsorption capacity of the chelating resin was estimated to be 130.25 mg g(-1) at 298 K. About 99% of adsorbed U(VI) can be desorbed from PAMAMG3-SDB by a simple acid treatment suggesting that the chelating resin is reusable.