Fundamentals and Techniques of Biophysics and Molecular Biology
... Due to a rise in the concentration of H + ions at pH<pHPZC, the functional moieties in hydrogel adsorbent become positively charged, leading to cation exchange. However, at pH > pHPZC the functional moieties are negatively charged due to excessive concentration of OHions, leading to anion exchange [170]. Saber-Samandari et al. synthesized Cellulose-Graft-Polyacrylamide/Hydroxyapatite hydrogel composite for the removal of Cu 2+ ions. ...
... Due to a rise in the concentration of H + ions at pH < pH PZC, the functional moieties in hydrogel adsorbent become positively charged, leading to cation exchange. However, at pH > pH PZC the functional moieties are negatively charged due to excessive concentration of OHions, leading to anion exchange [170]. Saber-Samandari et al. synthesized Cellulose-Graft-Polyacrylamide/Hydroxyapatite hydrogel composite for the removal of Cu 2+ ions. ...
Water is a vital resource that is required for social and economic development. A rapid increase in industrialization and numerous anthropogenic activities have resulted in severe water contamination. In particular, the contamination caused by heavy metal discharge has a negative impact on human health and the aquatic environment due to the non-biodegradability, toxicity, and carcinogenic effects of heavy metals. Thus, there is an immediate need to recycle wastewater before releasing heavy metals into water bodies. Hydrogels, as potent adsorbent materials, are a good contenders for treating toxic heavy metals in wastewater. Hydrogels are a soft matter formed via the cross-linking of natural or synthetic polymers to develop a three-dimensional mesh structure. The inherent properties of hydrogels, such as biodegradability, swell-ability, and functionalization, have made them superior applications for heavy metal removal. In this review, we have emphasized the recent development in the synthesis of hydrogel-based adsorbent materials. The review starts with a discussion on the methods used for recycling wastewater. The discussion then shifts to properties, classification based on various criteria, and surface functionality. In addition, the synthesis and adsorption mechanisms are explained in detail with the understanding of the regeneration, recovery, and reuse of hydrogel-based adsorbent materials. Therefore, the cost-effective, facile, easy to modify and biodegradable hydrogel may provide a long-term solution for heavy metal removal.
... Additionally, the particles in the stationary phase are not well defined; both particles and pores may vary in size. The stationary phase may interact negatively with a particle and affect retention durations, but column manufacturers take great effort to select innocuous stationary phases that minimize this problem [52]. As with other types of chromatography, extending the length of the column improves resolution, while increasing the diameter of the column increases column capacity. ...
Nanoplastics (NPs) are a rapidly developing subject that is relevant in environmental and food research, as well as in human toxicity, among other fields. NPs have recently been recognized as one of the least studied types of marine litter, but potentially one of the most hazardous. Several studies are now being reported on NPs in the environment including surface water and coast, snow, soil and in personal care products. However, the extent of contamination remains largely unknown due to fundamental challenges associated with isolation and analysis, and therefore, a methodological gap exists. This article summarizes the progress in environmental NPs analysis and makes a critical assessment of whether methods from nanoparticles analysis could be adopted to bridge the methodological gap. This review discussed the sample preparation and preconcentration protocol for NPs analysis and also examines the most appropriate approaches available at the moment, ranging from physical to chemical. This study also discusses the difficulties associated with improving existing methods and developing new ones. Although microscopical techniques are one of the most often used ways for imaging and thus quantification, they have the drawback of producing partial findings as they can be easily mixed up as biomolecules. At the moment, the combination of chemical analysis (i.e., spectroscopy) and newly developed alternative methods overcomes this limitation. In general, multiple analytical methods used in combination are likely to be needed to correctly detect and fully quantify NPs in environmental samples.
... At pH < pHPZC, the functional groups of adsorbent are positively charged because of an increase in H + concentration, resulting in cations exchange. On the other hand, functional groups are negatively charged when pH > pHPZC, which causes anions exchange (Figure 4) [123]. Zhou et al. [124] observed ion exchange and chelation between positively charged ions (Cd 2+ , Ni 2+ , and Pb 2+ ) and ionized/non-ionized carboxylic groups within the HG during the removal of these metal ions from aqueous solutions using cellulose-graft-acrylic acid hydrogel at pH 2.5-6.0, ...
Finding affordable and environment-friendly options to decontaminate wastewater generated with heavy metals and dyes to prevent the depletion of accessible freshwater resources is one of the indispensable challenges of the 21st century. Adsorption is yet to be the most effective and low-cost wastewater treatment method used for the removal of pollutants from wastewater, while naturally derived adsorbent materials have garnered tremendous attention. One promising example of such adsorbents is hydrogels (HGs), which constitute a three-dimensional polymeric network of hydrophilic groups that is highly capable of adsorbing a large quantity of metal ions and dyes from wastewater. Although HGs can also be prepared from synthetic polymers, natural polymers have improved environmental benignity. Recently, cellulose-based hydrogels (CBHs) have been extensively studied owing to their high abundance, biodegradability, non-toxicity, and excellent adsorption capacity. This review emphasizes different CBH adsorbents in the context of dyes and heavy metals removal from wastewater following diverse synthesis techniques and adsorption mechanisms. This study also summarizes various process parameters necessary to optimize adsorption capacity followed by future research directions.
... Formazanes are generally solid with relatively low melting points despite the size of their large particles (and the most common methods for preparing formazane compounds include diazines as salts (diazonium salts) with the hydrazine of the cyclic compounds (6)(7)(8)(9)(10) in an alkaline medium and the reaction takes place in controlled conditions of pH within the limits of (8-6) and a temperature of (0C°) and blindness of hydrazine is obtained from the aromatic aldehyde condensation (11)(12)(13)(14)(15) with phenylhydrazine or its compensators to give formazanes (16)(17)(18)(19)(20) . Formazane reagents were described by many researchers as ligands in the field of inorganic chemistry (21)(22)(23)(24)(25) , reagents in the field of analytical chemistry (26)(27)(28)(29)(30) , dyes in the field of industrial chemistry (31)(32)(33)(34)(35) , anti-cancer tumors in the field of biochemistry (36)(37)(38)(39)(40) and many other medical with pharmaceutical applications (41)(42)(43)(44)(45)(46)(47)(48)(49)(50) . ...
Formazane ligands are described by many chemical and physical properties that have increased their applications in several fields and therefore have been classified as reagents or ligands with donor or multi-sites. Multiple methods have been used to prepare aldamine and formazane reagents, including imination reactions, condensation, substitution, duplication, including the formation of the carbanion and the reaction of nitrogen in coupling reaction. It is followed by investigation of prepared ligands by various sources that improved all results in this paper via various spectral measurements in inorganic chemistry area like (Uv-Vis, FT.IR, H.NMR)-spectra, besides to other measurements in analytical area like: (solubility, chromatographic behavior, TLC-plate), besides to bio-assay as antibacterial compounds for determination of efficiency of inhibition and other chemical characterizations (melting points, Rf, …).
Natural compounds are very much important as they can cure diseases naturally without harmful effects from natural sources. Coumarin is also a natural compound and a large number of coumarins almost 1300 coumarins have been recognized from natural sources, mainly from green plants. Substitution on coumarins is responsible for their therapeutic, biochemical, and pharmacological applications. Coumarins are present in plants and can also be prepared in the laboratory. Coumarin, a drug is used in heat problems as it is an anti-coagulant i.e., it stops and helps to cure blood clots of blood vessels. This article is based upon the investigation of the absorption spectra of coumarin and its derivatives. The absorption spectra involve the study of UV-Visible spectroscopy and fluorescence spectroscopy. Solvatochromic shifts and the effects of the salts on fluorescence spectra and UV-Visible spectra will also be studied.
The technique of site-directed mutagenesis has been used to characterize gene and protein structure-function relationships, protein-protein interactions, binding domains of proteins, or active sites of enzymes for the last three decades. In this technique, a nucleotide sequence of interest is experimentally altered using synthetic oligonucleotides. The most commonly used approach is to use an oligonucleotide that is complementary to part of a single-stranded DNA template, but containing an internal mismatch to direct the mutation. In addition to single point mutations, this approach may also be used to construct multiple mutations, insertions, or deletions. As a result of its broad applicability in disease gene characterization studies, numerous commercial kits are now available, making this technique quick, straightforward, and reliable. In this chapter, we detail the steps involved in site-directed mutagenesis and highlight the essentials of this versatile technique based upon our experience.
The polymerase chain reaction (PCR) has dramatically altered how molecular studies are conducted as well as what questions can be asked. In addition to simplifying molecular tasks typically carried out with the use of recombinant DNA technology, PCR has allowed a spectrum of advances ranging from the identification of novel genes and pathogens to the quantitation of characterized nucleotide sequences. PCR can provide insights into the intricacies of single cells as well as the evolution of species. Some recent developments in instrumentation, methodology, and applications of the PCR are presented in this review.
Publisher Summary S1 nuclease analysis can be used to quantitate specific RNAs accurately in complex mixtures of RNAs of different sequence. S1 nuclease isolated from Aspergillus oryzae is an endodeoxyribonuclease and an endoribonuclease, which specifically hydrolyzes singlestranded nucleic acids to mono- and oligonucleotides with 5′-phosphate and 3′-hydroxyl groups. In the simplest application of the method, the size of the S1-resistant, labeled DNA is determined by denaturing the S1-resistant RNA–DNA hybrids, by subjecting the denatured material to gel electrophoresis with single-stranded DNA standands of known size and by detecting the S1-resistant DNA in the gel by autoradiography. At the resolution of sequencing gels, end-labeled S1-resistant fragments often resolve into two to six bands, each separated by a single nucleotide in length. Most mRNAs of higher eukaryotes are spliced RNA molecules. RNAs composed of two or three exons can be mapped by enzymatic and electrophoretic analyses of RNA-labeled DNA hybrids. While useful for mapping spliced RNAs of only two or three exons, interpretation of the data becomes increasingly more complex for spliced RNAs composed of larger numbers of exons.
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