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1.
Chemosphere ; 364: 143071, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39128776

RESUMO

Two microwave (MW) responsive heterojunction nanocomposite catalysts, i.e., α-Bi2O3/CoFe2O4 (BO/CFO) and ZnO/CoFe2O4 (ZO/CFO), with weight% ratio of 70/30, 50/50, 30/70 were synthesized by sequential thermal decomposition and co-precipitation methods, and used for the degradation of tetracycline (TC) under MW irradiation. The formation of desired catalysts was confirmed through the characterization results of XRD, FT-IR, SEM, VSM, UV-DRS, XPS, BET, etc. Using batch MW experiments, the catalyst dose, pH, initial TC concentration, reaction temperature, and MW power were optimized for TC removal. Under the following reaction conditions: catalyst dose ∼1 g/L, initial TC concentration ∼1 mg/L, temperature ∼90 °C, MW ∼450 W, BO/CFO, and ZO/CFO showed ∼97.55% and 88.23% TC degradation, respectively, after 5 min. The difference in the catalytic response against TC degradation indicated the difference in reflective loss (RL) between these two catalysts. The presence of other competitive anions has affected the removal efficiency of TC due to the scavenging effect. The radical trapping study revealed the significant contribution of TC degradation by hydroxyl radicals in the case of ZO/CFO, whereas for BO/CFO, superoxide (●O2-) and hydroxyl radicals (●OH) both played influential roles. The Z-scheme heterojunction of BO/CFO allowed the formation of ●O2- but the same was inhibited in type-II heterojunction of ZO/CFO due to the valance band position. The dielectric loss, magnetic loss, interfacial polarization, and high electrical conductivity, 'hotspots' were produced over the catalyst surface alongside electron-hole separation at heterojunctions, which were responsible for the generation of reactive oxygen species. In addition, Co3+/Co2+ and Fe3+/Fe2+ redox cycles have promoted ●O2- and sulfate radical production during persulfate application. Among the two MW responsive catalysts, BO/CFO could be a potential material for rapidly destroying emerging organic pollutants from wastewater without applying other oxidative chemicals under MW irradiation.

2.
Ultrason Sonochem ; 75: 105592, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34049154

RESUMO

The magnetic MgFe2O4 nanoparticles (NPs) were fabricated via a facile co-precipitation technique and was comprehensively characterized by XRD, FTIR, SEM, EDX and VSM. The prepared NPs were used as catalyst in presence of ultrasound (US) irradiation to activate persulfate (PS) for generation of sulfate radicals (SO4·-) for boosted degradation of toxic Brilliant Green (BG) dye. Preliminary experiments revealed that highest BG dye degradation efficiency of 91.63% was achieved at MgFe2O4 catalyst dose of 1.0 g/L, PS dose of 300 mg/L, and initial dye concentration of 70 ppm within 15 min of US irradiation. However, only US, US in presence of PS oxidation and US in presence of MgFe2O4 catalyst have shown 20.2%, 83.6% and 45.0% of BG dye removal, respectively. Furthermore, response surface methodology (RSM) based central composite design (CCD) was executed to investigate the effect of interaction between independent variables such as MgFe2O4 catalyst dose (0.5-1.5 g/L), PS dose (150-350 mg/L), initial BG dye concentration (50-150 ppm) and US irradiation time (4-12 min). The RSM based quadratic model was used to predict the experimental data, and the prediction accuracy was confirmed by analysis of variance (R2 = 0.98). The established RSM model has predicted the optimum experimental conditions as MgFe2O4 catalyst dose of 0.75 g/L, PS dose of 300 mg/L, initial dye concentration of 75 ppm and sonication time of 10 min. Subsequently, the treatment cost analysis was performed for all thirty experimental runs of CCD, and the RSM predicted response was found to be evidently optimum as this has delivered best economic condition (140 $/kg of BG removed) with respect to relative dye removal (%). COD removal and residual sulfate analysis have demonstrated satisfactory reduction of COD (90.31%) as well as sulfate ions (42.87 ppm) in the dye solution after treatment. Results of degradation pathway analysis portrayed the transformation of BG molecule (M/Z ratio 385) into simpler fractions with M/Z ratio of 193, 161, 73, and 61. Moreover, the toxicity analysis revealed that sono-catalytically activated PS system has efficiently reduced the toxicity level of BG dye from 93.9% to 5.13%.


Assuntos
Corantes/química , Custos e Análise de Custo , Compostos de Ferro/química , Compostos de Ferro/toxicidade , Compostos de Magnésio/química , Compostos de Magnésio/toxicidade , Compostos de Amônio Quaternário/química , Silicatos/química , Silicatos/toxicidade , Ondas Ultrassônicas , Catálise , Corantes/isolamento & purificação , Nanopartículas/química , Oxirredução , Compostos de Amônio Quaternário/isolamento & purificação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/economia , Purificação da Água/métodos
3.
Indian J Endocrinol Metab ; 23(4): 400-406, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31741896

RESUMO

As the first biologics produced by recombinant deoxyribonucleic acid (DNA) technology were approved in the late 1980s and consequently the exclusive marketing rights of most of these biological medicinal products have expired or will expire very shortly, it is quite evident that biosimilars are being developed and marketed in developed as well as developing countries in line with these expiries. Hence, there is an explosion of published papers and scientific programs on biological medicinal products and biosimilar insulins in the last decade or so. Each of these papers or scientific programs generated more questions than providing clinically useful answers. The specific aim of the medical literature or scientific programs were blurred due to lot of attention (created by the innovators) directed towards confusing terminologies, past mishaps with biosimilars (in the era with the absence of regulatory guidelines for biosimilars) diverting our attention from the matters relevant to clinicians and patients. One of the principle reason behind this phenomenon has been our poor understanding of the manufacturing process, regulatory pathways, and study endpoints involved in developing a biosimilar in the present era. This drawback resulted in a nonsystematic approach in analyzing the biosimilars and apparently resulting in confusion. This review attempts at demystifying certain facets of frequently encountered information on biosimilars and acquire a personal understanding on the same, rather than depending on conflicting versions floated at different continuing medical educations (CMEs) and Diabetes Congresses.

4.
Indian J Endocrinol Metab ; 21(3): 443-452, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28553603

RESUMO

INTRODUCTION: Insulin remains the cornerstone of therapy in a substantial number of patients with type 2 diabetes mellitus (T2DM). Inadequate knowledge regarding insulin usage is likely to influence its acceptance and adherence, and outcome of therapy, underscoring great need to investigate knowledge, attitude, and practice of insulin usage in patients with T2DM. METHODOLOGY: A cross-sectional registry-based retrospective study analyzed data collected from 748 respondents (male: 466, female: 282), mostly from high or middle economic status, who were enrolled as outpatient in a referral clinic during last 10 years (2006-2016), to assess the general characteristics of patients with type 2 diabetes and their baseline knowledge, attitude, and practice of insulin usage and injection practices. RESULTS: Mean ± standard deviation (SD) of duration of diabetes was 12.24 ± 7.60 years and mean ± SD duration of insulin therapy was 3.42 ± 4.18 years, which was initiated after a mean ± SD diabetes duration of 8.80 ± 6.42 years. Mean insulin dose per kilogram of body weight/day was 0.51 ± 0.27 units. Total daily dose of insulin was 33.36 ± 18.44 units and number of injections/day (mean ± SD) was 2.06 ± 0.73. Among the respondents, 58.96% were on human insulin and 35.70% were on analog insulin. Pen devices were used by 66.08% of the population whereas 31.76% used insulin syringes. The prevalence of lipohypertrophy (LH) was 12.57%, which was significantly (P < 0.001) associated with wrong technique with regard to injection angle (10.45% vs. 23.02%), site of injection (7.00% vs. 30.51%), rotation of site of injection (0.88% vs. 17.66%), and reuse of needle (5.77% vs. 15.19%). LH was also significantly (P < 0.05) associated with the use of human (14.74%) compared to analog insulin (8.24%). CONCLUSION: The current study highlights the unique patterns of insulin usage and associated high prevalence of LH among insulin users in India.

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