Applied Chemical Engineering

Abstract Thyroid diseases rank second among endocrine disorders, and prevalence of the diseases is higher in the elderly as compared to the younger population. An excess or deficiency of trace element contents in thyroid play important role in goitro- and carcinogenesis of gland. The correlations with age of the ten trace element (TE) contents (Ag, Co, Cr, Fe, Hg, Rb, Sb, Sc, Se, and Zn), I/Ag, I/Co, I/Cr, I/Fe, I/Hg, I/Rb, I/Sb, I/Sc, I/Se, and I/Zn content ratios, and inter relationships between TE contents and I/TE content ratios in normal thyroid of 33 females (age range 3.5–87 years) was investigated by instrumental neutron activation analysis. Our data reveal that the Co, Rb, Sb, Se, and Zn content increase, while the I/Co content ratio decrease in the normal thyroid of female during a lifespan. Therefore, a goitrogenic and tumorogenic effect of excessive Co, Rb, Sb, Se, and Zn level in the thyroid of old males and of disturbance in intrathyroidal I/Co relationships with increasing age may be assumed. Furthermore, it was found that the levels of Ag, Co, Cr, Fe, Hg, Rb, Sb, Se, and Zn in the thyroid gland are interconnected and depend on the content of I in it. Because I plays a decisive role in the function of the thyroid gland, the data obtained allow us to conclude that, along with I, at least such TEs as Co, Cr, Fe, Rb, Sb, Se, and Zn, if not directly, then indirectly, are involved in the process of thyroid hormone synthesis.

Abstract Tea is a highly common beverage worldwide. In addition to other particles, it contains a range of minerals and trace elements. Even though many are necessary for humans, some could be hazardous. Scientists have long been interested in the toxicity of trace metals and how they affect human health. By using Flame Atomic Absorption Spectrophotometer, the amounts of Ni, Cu, Cd, Zn, Pb, Cr, and Mn in eight black tea leaves, five green tea leaves, and their infusions were examined. The tea samples were collected from Bangladeshi local markets. The infusion time in boiling water was 5 and 10 minutes. Results revealed that the concentration ranges of Ni, Cu, Cd, Zn, Pb, Cr and Mn in black and green tea leaves and their infusions of 5 minutes and 10 minutes were 1.82 to 41.32, 13.54 to 29.87, 0.48 to 2.16, 0.30 to 36.52, 0.04 to 3.89, 0.00 to 4.95 and 112.67 to 187.98 ppm respectively. Concentrations of the elements found in samples were compared with maximum values reported by World Health Organization (WHO). To verify the accuracy of the work, standard reference material (SRM) and certified reference material (CRM) were also tested alongside tea samples. Geographical fluctuations, seasonal changes, chemical characteristics of the soil of the cultivated area, plant age, manufacturing, and packaging process are responsible for the variances in metal content of several tea brands. Cd, Pb, Cr, and Ni’s target hazard quotients (THQ) and the hazard index (HI) from drinking tea were both below one, indicating no risk to human health.

Abstract Toxic metal ions present in environmental water samples and other samples need to be detected for their removal. The detection of trace metal ions using an ion selective electrode (ISE) holds great significance in analytical chemistry. A 4-vinyl pyridine-ethyl acrylate copolymer-polyvinyl chloride (VE-PVC) based polymeric matrix (electrode) has been fabricated by free radical bulk polymerization method which is an example of a green and sustainable method capable of detecting Ni2+ ions even in trace amounts. To fabricate the polymeric matrix (electrode) (PME), VE has been used as an ionophore. Further, the effectiveness of Ni2+ ion ISE has also been investigated in the presence of surfactants and detergents. Its performance has also been analyzed in the presence of plasticizers. The electrode is found to be very useful for the estimation of Ni2+ ions using ethylenediaminetetraacetic acid by potentiometric titration and also in the estimation of presence of Ni2+ ions in water. Compared to other metal ions, the fabricated membrane electrode developed in this work has been found to show efficient and better selectivity towards Ni2+ ions.

Abstract We have successfully synthesized magnetic chitin (MCH) by incorporating iron oxide nanoparticles into biodegradable and abundantly naturally available chitin by the coprecipitation method. X-ray diffraction (XRD) characterization revealed formation of cubic inverse spinel structure of Fe3O4 nanoparticles. In addition to this, other characterization studies like energy dispersive X-ray analysis (EDX) and vibrating sample magnetometry (VSM) were also performed to have an insight into the compositional and functional nature of the structure. A detailed spectroscopic study of complex impedance and dielectric constant for a wide frequency range of ~1 Hz to 10 MHz at discrete temperatures ~300–400 K has been performed by us for the first time on MCH in order to understand various relaxation processes. From permittivity, we have estimated the height of the potential barrier to be ~95.8 ± 0.3 meV. Impedance measurements yielded an activation energy of ~35.85 meV. Thermogravimetric analysis (TGA) of the sample showed exceptionally high thermal stability of the sample with percentage of residual mass at 800 ℃ being ~73% in MCH, which is quite high in comparison to the pristine chitin. An S shaped curve obtained through VSM measurement confirmed the superparamagnetic nature of the nanocomposite. The study assumes significance in the present scenario of rising awareness about the environment and demand to explore alternative green materials with numerous biomedical/environmental applications ranging from drug delivery vehicles in COVID-19 treatment to food packaging.

Abstract The authors conducted free radical polymerization using an initiator to synthesize a copolymer of isobornyl methacrylate—Acrylonitrile (I/A). The reactivity ratios of I (r1) and A (r2) monomers were determined as r1 = 1.63 ± 0.14, r2 = 0.61 ± 0.06 for linear KT (Kelen–Tudos) method and r1 = 1.58, r2 = 0.60 for the EVM (Error-in-Variable Method). We interpreted 1H and 13C{1H} NMR spectra of the I/A copolymers using DEPT-135 and 2D HSQC spectra. The α-CH3 carbon in the I-unit was identified and confirmed using a 2D HSQC NMR spectrum, up to the level of triad of compositional and configurational sequences. The CH (C14) and β-CH2 carbon peaks were also identified up to the triad level and higher, respectively. A 2D TOCSY spectrum revealed geminal and vicinal interactions within various CH and β-CH2 protons. A 2D HMBC NMR spectrum provided a complete assignment of the coupling between nitrile, carbonyl, and quaternary carbons with CH3 and CH2 protons.

Abstract Zinc oxide is considered an effective photocatalyst for degradation of several organic contaminants found in wastewater. This work reports the biological synthesis of zinc oxide nanoparticles and its calcium nanocomposites to study the photocatalytic deterioration of two dyes, viz. Rhodamine B and Methylene blue, under natural sunlight. Nanoparticles were synthesized using zinc acetate and starch extracted from potato at pH 7–8. Potato starch acts as both a capping agent and a reducing agent. They were characterized spectroscopically via XRD, SEM, HR-TEM, EDAX and FT-IR techniques. Bean/spherical shaped ZnO NPs were obtained in the size range of 29–49 nm whereas calcium coating on ZnO decreased the particle size, i.e., 25–35 nm. Their photocatalytic ability to degrade Rhodamine B and Methylene blue was studied under natural sunlight and monitored using UV-Vis spectrophotometer. Synthesized ZnO nanoparticles and its calcium coated ZnO nanocomposites showed promising results in degradation of these dyes. Methylene blue was completely degraded in an hour at 8 mg of the sample. Although degradation of Rhodamine dye was slow, synthesized samples were effective catalysts as compared to the ones reported in the literature.

Abstract Click chemistry is totally an approach consisting of efficient and reliable reactions that bind two molecular building blocks and require no complex purification techniques. The aspire of achieving molecules with the desired characteristics and behaviour is the key to the click chemistry concept. In this concept, in order to obtain 1,2,3-triazole products as diversely functionalized molecules, copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has been widely used for years in the field of materials science, organic synthesis and the biochemistry. This review focusses on the importance of click chemistry for obtaining biologically active triazole molecules and therefore the applications of such 1,2,3-triazole derivatives in medicinal chemistry field are highlighted.

Abstract Tizanidine is an imidazoline derivative with the agonistic activity of central alpha 2 receptors at both the spinal and supra-spinal levels. It was prepared for the first time in 1978 and approved for use in 1996. The present review focuses on all methods used for the synthesis of tizanidine, related compounds and intermediates. This review article covers all the methods that have been used in the preparation of tizanidine since its discovery until now. Methods used for the preparation of tizanidine-related compounds are also covered. This review gives those interested in drug synthesis and designs the ability to form a complete picture of the preparation of this drug, as well as providing the opportunity for the synthesis of other drugs developed from this drug to increase activity and/or reduce side effects.

Abstract The primary component for human health is food quality and its safety. The world has crossed 8 billion population highlighting major demand to fulfil high consumption food requirement. To overcome food security issue, inorganic farming trend is booming. In the process of boosting agriculture and allied products, unethical practices of using pesticides achieve heights. Protection of plants is necessary from weeds and pests. Thus, in order, to minimize the curb of unwanted growth of weeds and pest attack, pesticides act as an agent for protection and helping for immense production of crops. Therefore, swift and precise detection of harmful pesticides in agriculture products is required in urgent demand. In this review, the distinct organic material-based sensor such as colorimetric sensing, fluorescent sensors, gas chromatography-mass spectrometry, and liquid chromatography, with the organic compounds as sensing elements to monitor pesticides level in distinct samples due to their specificity, reusability, stability, high sensitivity, and selectivity. Apart from it, this study provides a comprehensive overview of the recent major advancement in organic sensing elements in electrochemical sensor pesticides detection based on molecularly imprinted, multimodal sensor polydopamine and conductive polymer at low-cost production.

Abstract Schiff bases are a class of organic compounds which have good chelating properties. Due to this, they can form complexes with metal ions of the transition series. Schiff bases and their derivatives are bioactive and hence find widespread uses in various fields of inorganic, organic and medicinal chemistry. These are synthesised by condensation reactions and have been studied extensively as they can exhibit biological properties like anti-oxidant, anti-fungal, anti-cancer, anti-bacterial and anti-microbial, apart from finding uses in the field of material science. With the advent of nanotechnology and its increasing importance, the introduction of nanoparticles of Schiff bases can increase the effectiveness of their various biological properties. In the present article, we aim at providing an exhaustive review of the behaviour of metal complexes of Schiff bases and their various derivatives as anti-oxidant and anti-fungal agents. The most pertinent and contemporary literature has been chosen for this review article.

Abstract Peptide chemistry has emerged as one of the growing fields of research. Peptide chemistry has positively impacted various areas, including biochemistry, medicine, hormonal therapy, drug delivery, food and the cosmetic industry, materials science, and nanotechnology, via the development of ways to change and imitate the shape and function of peptide structures. The structural changes of peptides and the employment of innovative synthetic techniques have left an indelible mark on a number of scientific disciplines. Numerous nanostructures based on simple and complicated peptides have been constructed so far; however, cyclic peptides have attracted a great deal of interest from the scientific community due to their wide range of applications and distinctive properties. These properties include self-assembly, morphogenesis, and charge distribution, among others. In addition, nanostructured cyclic peptides offer increased and effective performance due to their high stability, prolonged plasma half-life, membrane permeability, and efficient transport, among other attributes. Recent work indicates the manufacture of nanostructured cyclic peptides by chemical means. In this review, a brief investigation of the morphology of cyclic peptides was conducted. In addition, the therapeutic potential of these nanostructured cyclic peptides and the prognosis for a variety of potential applications are also discussed.