Organic Compounds Research Articles

Chronic lead poisoning–induced budgerigar liver damage, gut microbiota dysbiosis, and metabolic disorder

Birds are sensitive to heavy metal pollution, and lead (Pb) contamination can negatively affect their liver and gut. Therefore, we used budgerigars to examine liver and gut toxicosis caused by Pb exposure in bird, and the possible toxic mechanisms. The findings showed Pb exposure increased liver weight and decreased body weight. Moreover, histopathological and immunofluorescence assay results demonstrated obvious liver damage and cell apoptosis increased in Pb- treated budgerigars. Quantitative polymerase chain reaction (qPCR) results also showed Pb caused an increase in apoptosis by inhibiting the PPAR-γ/PI3K/Akt pathway. The gut microbe analyses indicated Firmicutes, Proteobacteria, and Bacteroidetes were dominant microbial phyla, and Network analysis results shown Arthrobacter, Bradyrhizobium and Alloprevotella as the hubs of Modules I, II, and III, respectively. Phenylpropanoids and polyketides, Organoheterocyclic compounds, Organic oxygen compounds, and Organic nitrogen compounds were dominant metabolite superclasses. Tauroursodeoxycholic acid, taurochenodeoxycholic acid (sodium salt), and 2-[2-(5-bromo-2-pyridyl)diaz-1-enyl]-5-(diethylamino)phenol were significantly enriched in the Pb-treated group. It showed that 41 Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologues and 183 pathways differed between the Pb-treated and control budgerigars using microbial and metabolomic data. Moreover, orthogonal partial least-squares discrimination analysis (OPLS-DA) based on microbial and metabolite indicated distinct clusters in the Pb-treated and control groups. Additionally, the correlation analysis results indicated that a positive correlation for the Pb-treated and control groups between gut microbiota and metabolomic data, respectively. Furthermore, the microenvironment of the gut and liver were found to affect each other, and this study demonstrated heavy metal especially Pb may pose serious health risks to birds through the “gut–liver axis” too.

Electrochemically polymerized dopamine activated carbon paste sensor for selective and sensitive detection of rutin in the presence of riboflavin

In this work, a sensor was developed for the quantification of RT in food and medicine samples using electro-polymerization of dopamine (DA) on the surface of a carbon paste electrode in 0.2 M phosphate buffered saline (PBS) of 7.0 pH by cyclic voltammetry. The surface properties of bare carbon paste electrode (BCPE) and poly (DA) modified carbon paste electrode (PDAMCPE) were studied using scanning electron microscopy (SEM), electrochemical impedance study (EIS), and cyclic voltammetry (CV) techniques. Two electron two proton transfer process was seen during the electrochemical reaction of RT with adsorption-controlled process. Under optimum conditions, the peak current increased linearly with an increase in RT concentration for CV in the range of 0.4 to 2.0 μM and differential pulse voltammetry (DPV) in the range of 0.4 to 2.5 μM and the limit of detection (LOD) was found to be 0.0045 μΜ and for CV and 0.079 μM for DPV techniques respectively. Even in the presence of some interferents like organic compounds and metal ions, the developed electrode exhibits good anti-interference ability for RT, and good selectivity was obtained for RT in the presence of riboflavin (RF). The developed sensor presents good stability, repeatability, and reproducibility. The CV measurement was performed for the analysis of RT in real samples such as green tea and medicine samples which showed a good recovery and this work has been not reported previously.

An Exceptional Valorization of CuO Nanoparticles in Ionic Liquids as an Efficient Medium for the Electrophilic Substitution of Indole Towards the Formation of Bis(indolyl)methanes

Aim: Ionic liquids are promising green solvents with simple but unique structure-related physical properties such as negligible vapour pressure, exceptional thermal conductivity, remarkable thermal stability and their suitability and inertness towards a broad range of catalytic applications. CuO NPs have been addressed as a cost-effective and a reagent of a choice that necessitates only mild reaction conditions to offer a high yield of the desired products with exceptional selectivity in a short duration of time. Therefore, in the present work, attempts have been made to explore the catalytic potentials of CuO NPs in an ionic liquid medium to synthesize biologically important bis(indolyl)methanes. Background: Catalytic explorations of metal oxide nanoparticles in ionic liquids offers a cooperative effect that has a significant impact on the kinetics as well as on the outcome of the reaction. Therefore, such catalytic systems in the present times have seized the scientific community's interest from the perspectives of sustainable development in synthetic organic chemistry. The combination of metal oxide nanoparticles with highly tunable ionic liquids is not only used to synthesize simple organic molecules but also explored in the synthesis of complex organic molecules of high commercial and biological relevance. Objectives: The current work offers a rapid and robust protocol for synthesizing bis(indolyl)methanes via electrophilic substitution reaction between indole and various aldehydes in the presence of a CuO nanoparticles-ionic liquid system. The discussion focuses on the high tolerance of different functionalities by the catalytic system leading to the synthesis of bis(indolyl)methanes. Methods: CuO NPs have been synthesized via the co-precipitation method using ionic liquid. The applicability of metal oxide nanoparticles-IL matrix was further investigated in synthesizing bis(indolyl)methanes. Results: The FT-IR absorption below 600 cm-1 and the XRD pattern showing all the peaks in the diffraction diagram revealed the formation of CuO NPs. FESEM images show the flake-shaped morphology of CuO NPs and are found to be separated from the agglomerated clusters Conclusion: Ionic liquid-CuO NPs matrix reveals good to exceptional catalytic properties, and their advancements as a catalytic system at room temperature open new avenues for synthetic organic chemists.

Surface polarity modulation enables high-performance polyamide membranes for separation of polar/non-polar organic solvent mixtures

Achieving highly selective separation of organic mixtures is crucial to modern fine chemicals and pharmaceutical industries. The membrane-based organic solvent reverse osmosis (OSRO) technology is expected to break through this barrier. The key to achieving the separation of organic mixed liquids is to design the OSRO membrane as needed based on the physical and chemical properties of the target separation solvent. However, this poses a huge challenge to traditional OSRO membranes. In this work, we report composite polyamide (PA) OSRO membranes with ultrahigh polar/non-polar organic mixture selectivity. The surface polarity of the composite PA membrane is increased by coating a layer of Fe3+/tannic acid (Fe3+/TA) layer on the surface of the PA membrane. The enhanced surface polarity increases the interaction difference between polar and non-polar solvents and the membrane. And a polarization layer is formed on the membrane surface, which weakens the concentration polarization effect on the membrane surface. Under high-concentration feed liquid (the mass ratio of methanol/hexane is 7:3), the separation factor of the prepared membrane reaches 218, which is the highest value of all OSRO membranes reported so far. For the first time, we establish a partial flux analysis for the OSRO process. This analysis unravels the pressure, concentration dependence, and sensitivity of separation performance. It provides novel insights into the design of high-performance OSRO membranes.

Recent Advances in Biomedical Nanotechnology Related to Natural Products.

Natural product processing via nanotechnology has opened the door to innovative and significant applications in medical fields. On one hand, plants-derived bioactive ingredients such as phenols, pentacyclic triterpenes and flavonoids exhibit significant pharmacological activities, on another hand, most of them are hydrophobic in nature, posing challenges to their use. To overcome this issue, nanoencapsulation technology is employed to encapsulate these lipophilic compounds and enhance their bioavailability. In this regard, various nano-sized vehicles, including degradable functional polymer organic compounds, mesoporous silicon or carbon materials, offer superior stability and retention for bioactive ingredients against decomposition and loss during delivery as well as sustained release. On the other hand, some naturally occurring polymers, lipids and even microorganisms, which constitute a significant portion of Earth's biomass, show promising potential for biomedical applications as well. Through nano-processing, these natural products can be developed into nano-delivery systems with desirable characteristics for encapsulation a wide range of bioactive components and therapeutic agents, facilitating in vivo drug transport. Beyond the presentation of the most recent nanoencapsulation and nano-processing advancements with formulations mainly based on natural products, this review emphasizes the importance of their physicochemical properties at the nanoscale and their potential in disease therapy.

Green and Convenient Synthesis of Pharmaceutically Active Mono and Bis-dihydroquinazolines via a One-pot Multicomponent Reaction Under Sulfamic Acid Catalysis

Introduction: Multicomponent reactions (MCRs) and green chemistry are essential criteria for the development of efficient chemical syntheses for valuable organic compounds. Method: The design, synthesis, and development of sustainable procedures for the production of novel biological and pharmaceutical molecules have gained high importance. Herein, an environmentally benign synthesis of mono- and bis-2,3-dihydroquinazolin-4(1H)-ones as pharmaceutically active compounds was carried out in good to high yields of 80-99% within 45-120 minutes. Result: The desired products were synthesized via three-component and pseudo five-component condensations of isatoic anhydride, a primary amine (aniline or ammonium acetate), and an aldehyde/dialdehyde using sulfamic acid (20%) as a solid acidic catalyst under the solvent-free condition at 100°C. Conclusion: The easy work-up procedure, metal-free and environmentally benign catalyst, green reaction conditions for performing MCRs, and high yields of pure products are some advantages of the presented protocol.

Schiff Bases: Versatile Mediators of Medicinal and Multifunctional Advancements

Abstract: This review aims to shed light on the profound implications of Schiff Bases in combating a spectrum of pathogens by delving into their complex classification, synthesis, and reactions. The investigation also covers the varied molecular properties of Schiff bases, highlighting their potential use as chelating agents in coordination chemistry. Moreover, the investigation explores the discerning nature of Schiff Bases about metal ions and their adeptness in establishing intricate associations, highlighting their significance in metal coordination chemistry and specialized pharmaceutical transport mechanisms. Moreover, the review delves into the synthetic capacity of Schiff Bases, highlighting their importance in synthetic methodologies due to their exceptional adaptability, selectivity, and structural similarity to organic compounds. The methodology employs a rigorous systematic literature review to understand Schiff Bases comprehensively. This involves a meticulous analysis of various research articles and publications, allowing for a comprehensive exploration of the topic. The assessment of experimental investigations contributes to comprehending their molecular attributes, specificity for metal ions, and capacity for synthesis. The presented analysis amalgamates a multitude of sources to provide a nuanced and comprehensive viewpoint on the subject matter of Schiff Bases. The findings underscore the multifaceted utility of Schiff Bases in the fight against pathogens, their adaptability as chelating compounds, and their discerning affinity for metal ions. The examination of synthesis highlights their profound importance in synthetic methodologies and their striking resemblance to compounds found in living organisms. In conclusion, this analysis reveals Schiff Bases as highly adaptable compounds with potential in antimicrobial therapy, coordination chemistry, and precision drug delivery. The distinctive molecular attributes of these substances, functioning as chelators, contribute to their notable importance. The ability of Schiff bases to form complexes and their preference for metal ions highlight the wide range of applications for these molecules. Schiff Bases have a transformative effect on chemistry and medicine as we investigate their synthetic potential, driven by their versatility and structural similarity to biological compounds.

From trash to treasure: Cattle manure as a potent green corrosion inhibitor

The novelty of this study attributes establishing cattle manure as a potent and sustainable green corrosion inhibitor and identifying organic compounds accountable for the same. A simple and convenient maceration method was used for the extraction of a novel, eco-friendly, low-cost, efficient, and water-soluble green corrosion inhibitor from cattle manure. The inhibitor has been characterized through different spectroscopic, spectrometric, and chemical confirmatory tests. The efficacy of the cow manure extract (CME) in mitigating chloride-induced corrosion on mild steel was evaluated through electrochemical impedance and polarization studies at ambient conditions. Electrochemical corrosion monitoring revealed the sustainability of CME as a highly efficient inhibitor from a low-cost agricultural biowaste. Post-corrosion characterizations demonstrated the substantial film-forming characteristics of the CME. Mass spectrometry of the corrosion products assisted in identifying the phytochemicals contributing significantly to the film formation. This study defines an ecological route for agricultural solid waste management.

Enhanced reaction extraction distillation via multi-objective optimization and 4E analysis for sustainable recovery of organic compounds from wastewater

Resource utilization and sustainable treatment of wastewater, which can achieve efficient energy utilization and environmental protection, have received hot social attention. Tetrahydrofuran and methanol are the two most common substances in pharmaceutical wastewater. It is very necessary to explore the wastewater treatment process containing these two substances. In this study, extractive distillation and reactive distillation were proposed to effectively separate the tetrahydrofuran-methanol-water component of pharmaceutical wastewater. To further reduce energy consumption, two strengthening processes, double-column reactive-extractive distillation and reactive-extractive dividing wall column distillation were designed. Taking the minimum operating and equipment cost as the objective function, the processes were optimized by using the multi-objective genetic optimization algorithm to obtain the best process parameters. Four processes were evaluated in terms of total annual cost, energy consumption, gas emissions and thermodynamic efficiency. Compared to the traditional three-column extractive distillation process, the above-mentioned four aspects of the reactive-extractive dividing wall column process was reduced by 40.63%, 43.13%, 43.14% and 17.71%, respectively. The reactive-extractive dividing wall column distillation process is of great significance for the efficient purification of valuable organic matter in wastewater and environmental protection.

Removal of encapsulant ethylene-vinyl acetate for recycling of photovoltaic modules: Hansen solubility parameters analysis

Delamination of photovoltaic modules is crucial for the recovery of solar cell materials. In this article, we investigate the swelling of ethylene-vinyl acetate (EVA) using various organic solvents at a temperature range between 25 to 55°C. The swelling of the encapsulant EVA caused by the interaction of organic solvents aids in the separation of glass, solar cell, and Tedlar layer in the recycling of photovoltaic modules. Further, we quantify the interactions between the encapsulant EVA and the organic solvents by the solvent weight ratio and solvent volume ratio of EVA. The quantification of interactions between encapsulant EVA and various organic solvents is used to estimate the Hansen solubility parameters of encapsulant EVA. The temperature-dependent variation of physical properties of organic solvents and their effect on encapsulant EVA swelling are described. Organic solvents retained in encapsulant EVA matrix after drying at room temperature can be viewed as a method to reduce emissions of volatile organic compounds during recycling. Additionally, our experiments suggest that d-limonene, xylene, and toluene are the most effective solvents for delamination of end-of-life photovoltaic modules for recycling.

Bioconversion of lavender oil extraction wastes through cultivation of Pleurotus eryngii var. ferulae: Its effects on yield, nutritional content and antioxidant capacity of the mushroom

The study was carried out to investigate the effect of growing media prepared by mixing different ratios of poplar sawdust (PS) and lavender extraction wastes such as lavender straw (LS) and lavender flower wastes (LFW), on the cultivation cycle, yield and biological efficiency (BE%), nutritional profil and antioxidant capacity of Pleurotus eryngii var. Ferulae mushroom. Moreover, functional and organic compounds of the fruiting body were examined by FTIR analysis. The mushroom production was experimented with seven different growing media. A raised yield of 216.3 g/kg ±6.4 g/kg and BE% of 61.8 ± 1.8% were recorded in the growing medium where the PS, LS and LWF were used in the ratio of 5:3:2, whereas the maximum protein content (17.94 ± 0.04 g100 g-1), total phenolic content (5.09 ± 0.08 mg GAE g−1), ABTS (54.36 ± 2.39 μmol TE g−1) and CUPRAC (58.89 ± 0.91 μmol TE g−1) were observed in the growing medium prepared with mixture of PS and LS (the ratio of 7:3). Moreover, all the growing media added LS and LFW resulted in improved mushroom yield, the nutritional profile and antioxidant capacity of P. eryngii var. Ferulae when compared to the control medium. According to the results, LS and LFW can be used as efficient, cost-effective and promising substrates for the production of P eryngii var. Ferulae, a valuable medicinal and edible mushroom species.

Metagenomes from microbial populations beneath a chromium waste tip give insight into the mechanism of Cr (VI) reduction

Dumped Chromium Ore Processing Residue (COPR) at legacy sites poses a threat to health through leaching of toxic Cr(VI) into groundwater. Previous work implicates microbial activity in reducing Cr(VI) to less mobile and toxic Cr(III), but the mechanism has not been explored. To address this question a combined metagenomic and geochemical study was undertaken. Soil samples from below the COPR waste were used to establish anaerobic microcosms which were challenged with Cr(VI), with or without acetate as an electron donor, and incubated for 70 days. Cr was rapidly reduced in both systems, which also reduced nitrate, nitrite then sulfate, but this sequence was accelerated in the acetate amended microcosms. 16S rRNA gene sequencing revealed that the original soil sample was diverse but both microcosm systems became less diverse by the end of the experiment. A high proportion of 16S rRNA gene reads and metagenome-assembled genomes (MAGs) with high completeness could not be taxonomically classified, highlighting the distinctiveness of these alkaline Cr impacted systems. Examination of the coding capacity revealed widespread capability for metal tolerance and Fe uptake and storage, and both populations possessed metabolic capability to degrade a wide range of organic molecules. The relative abundance of genes for fatty acid degradation was 4× higher in the unamended compared to the acetate amended system, whereas the capacity for dissimilatory sulfate metabolism was 3× higher in the acetate amended system. We demonstrate that naturally occurring in situ bacterial populations have the metabolic capability to couple acetate oxidation to sequential reduction of electron acceptors which can reduce Cr(VI) to less mobile and toxic Cr(III), and that microbially produced sulfide may be important in reductive precipitation of chromate. This capability could be harnessed to create a Cr(VI) trap-zone beneath COPR tips without the need to disturb the waste.

Plasmon AgNPs/MoS2/ZnO nanorods array ternary heterojunctions enabling high-efficiency solar-light energy utilization for photocatalysis and recyclable SERS detection

BackgroundSurface-enhanced Raman scattering (SERS) has gained widespread use in molecule-level detection benefiting from its high sensitivity, nondestructive data acquisition, and capacity for providing molecular fingerprint information. However, the strong adhesion of target molecules to the substrate (known as the "memory effect") inherently hinders the reusability of SERS substrates. Research has shown that self-cleaning SERS substrates based on versatile semiconductor materials with SERS enhancement capabilities and solar photocatalytic properties offer an effective platform for the sensitive detection and degradation of harmful molecules. ResultsIn this research, a resuable SERS-active substrate was facilely fabricated by anchoring silver nanoparticles (AgNPs) to the edges of MoS2 nanosheet decorated on ZnO nanorod arrays (NRAs). This innovative design exhibited a remarkable SERS enhancement factor (EF) of 4.6 × 107 and demonstrated significant solar photocatalytic efficiency. Such superior characteristics of ternary plasma heterojunction were ascribable to the synergistic effect of the “Schottky barrier” and “hot spots” between MoS2 and AgNPs, the inherent chemical enhancement proficiency of the MoS2/ZnO NRAs heterojunction, as well as the ultrafast electron transfer within the ternary heterojunction. SignificanceThe developed ternary heterojunction substrate enabled highly sensitive SERS detection of trace amounts of organic molecules. Moreover, this SERS substrate exhibited self-cleaning and recyclability via solar-light-driven photocatalysis. This bifunctional recyclable SERS substrate proved capable of meeting various requirements for routine monitoring of environmental organic pollutants and provided a robust avenue for advancing energy utilization materials that serve as high-performance SERS sensors and catalysts.

Mechanochemical and Microwave Multistep Organic Reactions

Abstract: The development of more sustainable chemical reactions and processes has been the focus of recent research activities. Advances in the field of organic synthesis have led to the emergence of new methodologies and techniques involving non-conventional energy sources. These include the applications of mechanical energy (mechanochemistry) and microwave radiation (MW) methods. This article reviews the advances in multistep organic synthesis of biologically relevant organic molecules using mechanochemistry and microwave techniques. Among them, various heterocyclic molecules (with nitrogen, oxygen, and sulphur atoms), amides, and peptides have been synthesized by multistep mechanochemical or MW reactions. Performing multiple synthetic steps using more sustainable methods shows cumulative advantages over multistep processes under conventional conditions in terms of reduced solvent use, shorter reaction times, better turnovers, and reaction yields. Simplification of protocols by carrying out two or more reaction steps in the same reaction vessel is another advantage of multistep syntheses.

Accelerator mass spectrometry measurements of 233U in groundwater, soil and vegetation at a legacy radioactive waste site

Low-level radioactive wastes were disposed at the Little Forest Legacy Site (LFLS) near Sydney, Australia between 1960 and 1968. According to the disposal records, 233U contributes a significant portion of the inventory of actinide activity buried in the LFLS trenches. Although the presence of 233U in environmental samples from LFLS has been previously inferred from alpha-spectrometry measurements, it has been difficult to quantify because the 233U and 234U α-peaks are superimposed. Therefore, the amounts of 233U in groundwaters, soils and vegetation from the vicinity of the LFLS were measured using accelerator mass spectrometry (AMS). The AMS results show the presence of 233U in numerous environmental samples, particularly those obtained within, and in the immediate vicinity of, the trenched area. There is evidence for dispersion of 233U in groundwater (possibly mobilised by co-disposed organic liquids), and the data also suggest other sources of 233U contamination in addition to the trench wastes. These may include leakages and spills from waste drums as well as waste burnings, which also occurred at the site. The AMS results confirm the historic information regarding disposal of 233U in the LFLS trenches. The AMS technique has been valuable to ascertain the distribution and environmental behaviour of 233U at the LFLS and the results demonstrate the applicability of AMS for evaluating contamination of 233U at other radioactive waste sites.

Quantitative Analogue Simulation of Planar Molecules.

Synthetic quantum systems provide a pathway for exploring the physics of complex quantum matter in a programmable fashion. This approach becomes particularly advantageous when it comes to systems that are thermodynamically unfavorable. By sculpting the potential landscape of Cu(111) surfaces with carbon monoxide quantum corrals in a cryogenic scanning tunneling microscope, we created analogue simulators of planar organic molecules, including antiaromatic and non-Kekulé species that are generally reactive or unstable. Spectroscopic imaging of such synthetic molecules reveals close replications of molecular orbitals obtained from ab initio calculations of the organic molecules. We further illustrate the quantitative nature of such analogue simulators by faithful extraction of bond orders and global aromaticity indices, which are otherwise technically daunting using real molecules. Our approach therefore sets the stage for new research frontiers pertaining to the quantum physics and chemistry of designer nanostructures.

Quasi-degenerate extension of local N-electron valence state perturbation theory with pair-natural orbital method based on localized virtual molecular orbitals.

Chemical phenomena involving near-degenerate electronic states, such as conical intersections or avoided crossing, can be properly described using quasi-degenerate perturbation theory. This study proposed a highly scalable quasi-degenerate second-order N-electron valence state perturbation theory (QD-NEVPT2) using the local pair-natural orbital (PNO) method. Our recent study showed an efficient implementation of the PNO-based state-specific NEVPT2 method using orthonormal localized virtual molecular orbitals (LVMOs) as an intermediate local basis. This study derived the state-coupling (or off-diagonal) terms to implement QD-NEVPT2 in an alternative manner to enhance efficiency based on the internally contracted basis and PNO overlap matrices between different references. To facilitate further acceleration, a local resolution-of-the-identity (RI) three-index integral generation algorithm was developed using LMOs and LVMOs. Although the NEVPT2 theory is considered to be less susceptible to the intruder-state problem (ISP), this study revealed that it can easily suffer from ISP when calculating high-lying excited states. We ameliorated this instability using the imaginary level shift technique. The PNO-QD-NEVPT2 calculations were performed on small organic molecules for the 30 lowest-lying states, as well as photoisomerization involving the conical intersection of 1,1-dimethyldibenzo[b,f] silepin with a cis-stilbene skeleton. These calculations revealed that the PNO-QD-NEVPT2 method yielded negligible errors compared to the canonical QD-NEVPT2 results. Furthermore, we tested its applicability to a large photoisomerization system using the green fluorescent protein model and the ten-state calculation of the large transition metal complex, showcasing that off-diagonal elements can be evaluated at a relatively low cost.

Co-Immobilization of ADH and GDH on Metal-Organic-Framework: An Effective Biocatalyst for Asymmetric Reduction of Ketones.

Chiral alcohols are not only important building blocks of various bioactive natural compounds and pharmaceuticals, but can serve as synthetic precursors for other valuable organic chemicals, thus the synthesis of these products is of great importance. Bio-catalysis represents one effective way to obtain these molecules, however, the weak stability and high cost of enzymes often hinder its broad application. In this work, we designed a biological nanoreactor by embedding alcohol dehydrogenase (ADH) and glucose dehydrogenase (GDH) in metal-organic-framework ZIF-8. The biocatalyst ADH&GDH@ZIF-8 could be applied to the asymmetric reduction of a series of ketones to give chiral alcohols in high yields (up to 99 %) and with excellent enantioselectivities (>99 %). In addition, the heterogeneous biocatalyst could be recycled and reused at least four times with slight activity decline. Moreover, E. coli containing ADH and GDH was immobilized by ZIF-8 to form biocatalyst E. coli@ZIF-8, which also exhibits good catalytic behaviours. Finally, the chiral alcohols are further converted to marketed drugs (R)-Fendiline, (S)-Rivastigmine and NPS R-568 respectively.

Enhanced removing of cyanobacterium by NZVI coupled with H2O2: Influencing factors and removal mechanisms

AbstractAs advanced oxidation processes (AOPs) is considered to be a highly effective approach for degrading organic pollutants, the simultaneous coagulation and oxidation process by the Fenton‐like reaction of nanoscale zero‐valent iron (NZVI) and hydrogen peroxide (H2O2) is investigated to eliminate the harmful cyanobacterium Microcystis aeruginosa in this study, and the process conditions are optimized using the central composite design of response surface methodology (RSM); in addition, the removal efficiency of M. aeruginosa (in terms of chlorophyll a, Chl a) and the verifications of the antioxidant abilities, as well as extracellular organic matters (EOM) and intracellular organic matters (IOM) are investigated under the optimized conditions. Results indicate that H2O2 concentration is the key factor affecting the Chl a removal efficiency, and the maximum Chl a removal reaches 98.10% under the optimized conditions: NZVI concentration 62.82 mg L−1, H2O2 concentration 54.2 mmol L−1, pH 4.38 and rotating speed 67 rpm. The high correlation coefficient (R2 > 0.80) of analysis of variance (ANOVA) demonstrates the RSM model is extremely significant and suitable for experimental results. Moreover, the total organic carbon (TOC) and fluorescent substances (soluble cyanobacteria metabolic byproducts, aromatic proteins II, humic and fulvic acid‐like compounds) for both EOM and IOM are enhanced removal. It is speculated the removal mechanisms of the Fenton‐like process of NZVI/H2O2 for cyanobacterium belongs to the combined actions of the oxidation of Fe(II)/H2O2 and the coagulation of Fe(III), which destroy the defense system and result in the removal of M. aeruginosa.

Material Classification Map Using Dual-Energy Method at Low-Energy X-Ray Spectrum: An Experimental and Monte Carlo Simulation Study

Abstract The objective of this article is to develop an effective method for material discrimination, distinguishing specifically between light metallic materials and heavy ones at low X-ray energies. In this research, Monte Carlo simulations are employed to investigate the influential factors affecting material discrimination. Initially, for result validation, the experimental setup is fully simulated based on the Monte Carlo method. The X-ray spectrum of 160 keV is simulated, and then it is registered after interacting with step wedges made of iron, aluminum, graphite, and ABS at specific thicknesses, capturing the radiation flux at each step. The results are compared with the experimental findings obtained from a dual-layer detector, demonstrating excellent agreement. In practice, the dual-layer detector comprises a low-energy GOS detector, a copper filter, and a high-energy CsI(Tl) detector. The energy spectra of the registered X-rays on each layer of detectors are obtained using the Monte Carlo method. Materials with low, medium, and high atomic numbers are chosen for analysis. These materials are categorized into three groups: organic materials (comprising both light and heavy organic and biological substances), light metals, and heavy metals. Discrimination between materials is achieved independently of their thickness by utilizing a material classification map (MCM) derived from a graph depicting the transmission ratio of low-energy X-ray photons versus the linear attenuation coefficient ratio for various materials with different atomic numbers. The results have been successfully validated through testing with various materials and thicknesses using both the experimental setup and Monte Carlo simulations.