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•Toxicity of PAHs is narrated.•Microbial and biocatalytic routes of PAHs degradation have been explained.•Bioremediation mechanism of PAHs degradation is discussed.•Effect of ...surfactants in PAH degradation is reviewed.•Commercial products for hydrocarbons treatment are discussed.
Polycyclic aromatic hydrocarbons (PAHs) are hazardous environmental pollutants with widespread and well-recognized health concerns. Amidst more than a hundred known PAHs, 16 are categorized as priority pollutants. Use of widely diverse biological machinery comprising bacteria, fungi, and algae harnessed from contaminated sites has emerged as an ecologically safe and sustainable approach for PAH degradation. The potential of these biological systems has been thoroughly examined to maximize the degradation of specific PAHs by understanding their detailed biochemical pathways, enzymatic system, and gene organization. Recent advancements in microbial genetic engineering and metabolomics using modern analytical tools have facilitated the bioremediation of such xenobiotics. This review explores the role of microbes, their biochemical pathways, genetic regulation of metabolic pathways, and the effect of biosurfactants against the backdrop of PAH substrate structures.
The field of site‐specific modification of proteins has drawn significant attention in recent years owing to its importance in various research areas such as the development of novel therapeutics and ...understanding the biochemical and cellular behaviors of proteins. The presence of a large number of reactive functional groups in the protein of interest and in the cellular environment renders modification at a specific site a highly challenging task. With the development of sophisticated chemical methodologies it is now possible to target a specific site of a protein with a desired modification, however, many challenges remain to be solved. In this context, transition metals in particular palladium‐mediated C−C bond‐forming and C−O bond‐cleavage reactions gained great interest owing to the unique catalytic properties of palladium. Palladium chemistry is being explored for protein modifications in vitro, on the cell surface, and within the cell. Very recently, palladium complexes have been applied for the rapid deprotection of several widely utilized cysteine protecting groups as well as in the removal of solubilizing tags to facilitate chemical protein synthesis. This Minireview highlights these advances and how the accumulated knowledge of palladium chemistry for small molecules is being impressively transferred to synthesis and modification of chemical proteins.
Making changes: Palladium chemistry is being significantly explored for protein modifications in vitro, on the cell surface, and within the cell. Very recently, palladium complexes have been applied for the rapid deprotection of several widely utilized cysteine protecting groups, as well as in the removal of solubilizing tags to facilitate chemical protein synthesis. This Minireview summarizes such advances.
In spite of their superior dissolution capacity for bioactive compounds, reduced environmental impact and low toxicity, the high viscosity of DES may affect the extraction capacity and efficiency, ...for which, necessary modification may be necessary. However, such changes can lead to a drastic reduction in the extraction yield because of the highly sensitive nature of the supramolecular structure of DES. To investigate the effect of molar ratio, water addition and temperature, ultrasound-assisted extraction of phenolic compounds from Aegle marmelos was performed with a series of DESs based on choline chloride and oxalic acid (DES: oxaline) with different molar ratio and water addition levels. HPLC-DAD was applied to quantify individual phenolic compounds. To understand the structural and physical characteristics under different processing conditions, FTIR, density and rheology analysis of oxaline were performed. Binary aqueous solvent mixtures were used as the reference. According to the experimental results, oxaline11 with 25% water and 80 °C was the best combination for extracting polyphenols from bael. The optimized condition enabled better cavitiational process by lowering viscosity and forming a stronger H-bonding between the DES and components, enhancing the extraction yield and capacity by >60% compared to conventional solvents. The results of this study highlight the potential application of deep eutectic solvent as an alternative to conventional organic solvents in food, cosmetic and pharmaceutical applications.
Cell-free DNA (cfDNA) is present in numerous body fluids and generally blood cells. It is undoubtedly the utmost promising tool among all components of liquid biopsy. Liquid biopsy is a specialized ...method investigating the non-solid biological tissue by revealing circulating cells, cell-free DNA, etc., that enter the body fluids. Since cancer cells disengage from compact tumors circulating in peripheral blood, evaluating cancer patients' blood profile is essential for the molecular level analysis of various tumor-derived constituents. Cell-free DNA samples can deliver a significant diagnosis in oncology, for instance, tumor heterogeneity, rapid tumor development, response to therapy and treatment, comprising immunotherapy, and mechanisms of cancer metastasis. Malignant growth at any phase can cause the occurrence of tumor cells in addition to fragments of neoplasticity. Liquid biopsy indicates diverse blood-based biomarkers comprising circulating tumor cells (CTCs), circulating tumor DNA (ctDNA) or cfDNA, circulating RNA (cfRNA), and exosomes. Cell-free DNAs are little DNA fragments circulating in plasma or serum, just as other fluids present in our body. Cell-free DNA involves primarily double-stranded nuclear DNA and mitochondrial DNA, present both on a surface level and in the vesicles' lumen. The probable origins of the tumor-inferred portion of cfDNA are apoptosis or tumor necrosis, lysis of CTCs or DNA release from the tumor cells into circulation. The evolution of innovations, refinement, and improvement in therapeutics to determine the fragment size of cfDNA and its distribution provide essential information related to pathological conditions of the cell, thus emerging as a promising indicator for clinical output in medical biotechnology.
In this paper, higher-order numerical schemes to the McKendrick–Von Foerster equation are presented when the death rate has singularity at the maximum age. The third, fourth-order schemes that are ...proposed here are based on the characteristics which are non-intersecting lines in this case, and are multi-step methods with appropriate corrections at each step. In fact, the convergence analysis of these schemes is discussed in detail. Moreover, numerical experiments are provided to validate the orders of convergence of the proposed third-order and fourth-order schemes.
•McKendrick-Von Foerster equation with singular mortality is considered.•Designed a higher order scheme.•Convergence of the proposed schemes is established.
·Basic requirements for exhibiting valence tatomerism.·Experimental methods to probe valence tautomerism/delocalization.·Theoretical calculations to rationalize the occurrence of valence tautomerism ...and/or to identify delocalization.·Valence tautomerism/charge delocalization in VT systems with o-dioxolenes.·Valence tautomerism/delocalized systems with o-aminophenol-based ligands.
The archetypal temperature-driven valence tautomeric process ‘CoIII(Cat)(SQ)’ ⇌ ‘CoII(SQ)2’ (spin state of cobalt changes from S = 0 to S = 3/2), where Cat2− and SQ·− are catecholato and semiquinonato redox-level, respectively, of the redox-active catecholate. Research on valence tautomerism has made notable advancement not only with new cobalt-catecholate systems but also with other metal ions and new redox-active ligands. The process is associated with changes in the charge distribution. Here some recent results on metal complexes of redox-active catecholates (only selected recent examples), o-amidophenolate and o-phenylenediamide ligands are presented.
The acetamidomethyl (Acm) moiety is a widely used cysteine protecting group for the chemical synthesis and semisynthesis of peptide and proteins. However, its removal is not straightforward and ...requires harsh reaction conditions and additional purification steps before and after the removal step, which extends the synthetic process and reduces the overall yield. To overcome these shortcomings, a method for rapid and efficient Acm removal using PdII complexes in aqueous medium is reported. We show, for the first time, the assembly of three peptide fragments in a one‐pot fashion by native chemical ligation where the Acm moiety was used to protect the N‐terminal Cys of the middle fragment. Importantly, an efficient synthesis of the ubiquitin‐like protein UBL‐5, which contains two native Cys residues, was accomplished through the one‐pot operation of three key steps, namely ligation, desulfurization, and Acm deprotection, highlighting the great utility of the new approach in protein synthesis.
Three in one: An efficient method for the deprotection of (acetamidomethyl)cysteine using Pd complexes in aqueous medium was introduced and applied to the one‐pot assembly of three peptides. UBL‐5 was thus synthesized by one‐pot native chemical ligation, desulfurization, and removal of the acetamidomethyl (Acm) group while keeping its two native Cys residues intact.
Herein, we demonstrate a facile fabrication of nickel cobalt oxide nanoflake decorated manganese cobalt oxide nanostick-arrays (MnCo2O4.5-NiCo2O4), as a hybrid electrode material through multistep ...hydrothermal protocols for high performance power device applications. Iron oxide nanoparticles decorated reduced graphene oxide (Fe-rGO) was synthesized through a simplistic reduction process of GO. The morphological features, specific surface areas and morphology dependent electrochemical activity of the as-prepared electrode materials have been investigated systematically. Our as-prepared manganese cobalt oxide/nickel cobalt oxide, MnCo2O4.5-NiCo2O4 (abbreviated as MCO/NCO) hybrid electrode reveals a highest specific capacitance (Cs) value of ∼2506 F g−1 as compared to the base MnCo2O4.5 (∼1220 F g−1) at 1 A g−1 constant current density. The higher Cs values of the hybrid composite can be credited to the synergistic property of MCO and NCO, which eventually facilitates electron transportation. In contrast, Fe-rGO shows a Cs value of ∼236 F g−1 at 1 A g−1. Moreover, an advanced asymmetric supercapacitor (ASC) device was fabricated utilizing MCO/NCO as positive and Fe-rGO as a negative electrode in presence of a potassium hydroxide (KOH) soaked laboratory Whatman 40 filter paper as separator. The device exhibits a Cs value of 170.8 F g−1 at 1 A g−1 together with a decent energy density of ∼34 Wh kg−1 (power density of 597.18 W kg−1 at 1 A g−1) and a longtime cyclic stability (90% Cs retention after 3000 Galvanostatic charge-discharge series). These results suggest superior application potential of our ASC for next -generation portable energy storage applications.
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•MnCo2O4.5-NiCo2O4 electrode material was prepared by a facile hydrothermal protocol.•Fe-rGO was synthesized by a low temperature reduction method.•The device was fabricated utilizing MnCo2O4.5-NiCo2O4 as cathode and Fe-rGO as an anode.•MnCo2O4.5-NiCo2O4//Fe-rGO exhibits superior electrochemical activity.
This study is aimed to investigate the effect of carbon nanotubes on the properties of lightweight aggregate concrete containing expanded glass and silica aerogel. Combinations of expanded glass ...(55%) and hydrophobic silica aerogel particles (45%) were used as lightweight aggregates. Carbon nanotubes were sonicated in the water with polycarboxylate superplasticizer by ultrasonication energy for 3 min. Study results show that incorporating multi-wall carbon nanotubes significantly influences the compressive strength and microstructural performance of aerogel based lightweight concrete. The addition of carbon nanotubes gained almost 41% improvement in compressive strength. SEM image of lightweight concrete shows a homogeneous dispersal of carbon nanotubes within the concrete structure. SEM image of the composite shows presence of C-S-H gel surrounding the carbon nanotubes, which confirms the cites of nanotubes for the higher growth of C-S-H gel. Besides, agglomeration of carbon nanotubes and the presence of ettringites was observed in the transition zone between the silica aerogel and cementitious materials. Additionally, flowability, water absorption, microscopy, X-ray powder diffraction, and semi-adiabatic calorimetry results were analyzed in this study.
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•Fe3O4 decorated RGO–SWCNH (FRS) was prepared by reduction of GO with SWCNH and Fe.•PDMS/FRS composites with tunable EMI SE was obtained by curing PDMS in a sugar cube.•The EMI SE ...decreases under compression due to the reduction of multiple reflections.•Microwave absorption occurs through the conductive network of SWCNH and RGO.
In the present era, the advanced technology demands for the fabrication of light weight and compressible high performance electromagnetic interference (EMI) shielding materials for adaptable shielding application in the area of modern electronic gadgets and telecommunication devices. This study highlights facile fabrication of such lightweight compressible porous polydimethylsiloxane (PDMS)/FRS Ferrous ferric oxide (Fe3O4) decorated reduced graphene oxide (RGO)/single wall carbon nanohorn (SWCNH) composite for tunable EMI shielding applications. The Fe powder used to reduce GO, was decorated on the SWCNH and RGO as Fe3O4 during the in situ reaction. FRS dispersed PDMS was allowed to soak and cured in a sugar cube, followed by leaching out of the sugar to obtain highly porous network structure with lightweight and compressible PDMS/FRS composite. The composite possessed an absorption-dominated good comprehensive EMI shielding performance, possibly due to both conductive dissipation and multiple reflections and scattering of EM waves by the inside 3D conductive RGO-SWCNH network with ferromagnetic Fe3O4 nanoparticles. The measurement of attenuation constant and loss tangent describe the absorption property of the composite. The shielding performance of the composite could be simply adjusted owing to its’ pressure induced compressible property, applicable as smart tunable EMI shielding material.
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