Photodegradation of a mixture of five pharmaceuticals commonly found in wastewater: Experimental and computational analysis.

Photochemical transformation of pharmaceuticals plays an important role in their natural attenuation, especially in lagoon-based wastewater treatment plants and surface waters receiving substantial sunlight. In this study, the photodegradation of five important pharmaceuticals was studied in samples obtained from a wastewater treatment plant and surface water sources. Batch photodegradation studies for a mixture of pharmaceuticals (diclofenac, sulfamethoxazole, acetaminophen, carbamazepine and gemfibrozil) were carried out in a photochemical reactor. Multiple aliquots of samples removed from the reactor during the experiment were analyzed through high-performance liquid chromatography (HPLC) coupled to a photodiode array (PDA) detector. Intermediate products formed due to photodegradation were identified by ultra-high-performance liquid chromatography coupled with a time-of-flight mass spectrometry (UHPLC-MS/MS). Diclofenac and sulfamethoxazole were found to undergo direct photodegradation due to strong light absorption, whereas the indirect route of photosensitized degradation in the presence of dissolved organic matter (DOM) and model humic acid was significant for acetaminophen, carbamazepine, and gemfibrozil. The reactive radicals such as hydroxyl (OH•), singlet oxygen (1O2) and excited states of DOM (*DOM) were predominantly responsible for the indirect photodegradation of acetaminophen, gemfibrozil and carbamazepine, respectively. Computational analysis revealed that chlorine and carbon atoms belonging to the benzene ring of diclofenac were more reactive to radical attack. Sulfamethoxazole photodegradation occurred through oxidation of the NH2 group. Acetaminophen was more susceptible to electrophilic radical attack at the O-11, and N-7 positions and carbon atoms ortho to the phenolic oxygen and the amine group. The double bonds between C-7, C-8 and C-13 were the most reactive sites for carbamazepine that participated in the phototransformation pathway. Organic matter plays a critical role in the photodegradation of emerging contaminants. The coupling of DFT calculations with UHPLC-MS/MS analysis provided insights on key functional groups participating in the phototransformation pathway. Thus, both parent pharmaceuticals and the photodegradation intermediates should be considered during wastewater treatment.

Photochemical fate of quaternary ammonium compounds (QACs) and degradation pathways predication through computational analysis.

Quaternary ammonium compounds (QACs) are commonly used in many products, such as disinfectants, detergents and personal care products. However, their widespread use has led to their ubiquitous presence in the environment, posing a potential risk to human and environmental health. Several methods, including direct and indirect photodegradation, have been explored to remove QACs such as benzylalkyldimethyl ammonium compounds (BACs) and alkyltrimethyl ammonium compounds (ATMACs) from the environment. Hence, in this research, a systematic review of the literature was conducted using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) method to understand the fate of these QACs during direct and indirect photodegradation in UV/H2O2, UV/PS, UV/PS/Cu2+, UV/chlorine, VUV/UV/chlorine, O3/UV and UV/O3/TiO2 systems which produce highly reactive radicals that rapidly react with the QACs, leading to their degradation. As a result of photodegradation, several transformation products (TPs) of QACs are formed, which can pose a greater risk to the environment and human health than the parent QACs. Only limited research in this area has been conducted with fewer QACs. Hence, quantum mechanical calculations such as density functional theory (DFT)-based computational calculations using Gaussian09 software package were used here to explain better the photo-resistant nature of a specific type of QACs, such as BACs C12-18 and ATMACs C12, C14, C18, and their transformation pathways, providing insights into active sites participating in the phototransformation. Recognizing that different advanced oxidation processes (AOPs) come with pros and cons in the elimination of QACs, this review also highlighted the importance of implementing each AOP concerning the formation of toxic transformation products and electrical energy per order (EEO), especially when QACs coexist with other emerging contaminants (ECs).

In silico evaluation of new mangiferin-based Positron Emission Tomography radiopharmaceuticals through the inhibition of metalloproteinase-9.

Metalloproteinase-9 (MMP-9) is a key protein in cancer advancement and metastasis owing to its ability to degrade some extracellular matrix components. Mangiferin, a natural polyphenolic compound, has demonstrated through experimental and theoretical studies to be a great anticancer agent for the selective inhibition of MMP-9. This work aimed to evaluate the utility of several fluorinated compounds obtained from MF as possible Positron Emission Tomography (PET) radiopharmaceuticals oriented to MMP-9. Density Functional Theory calculations of MF were made to obtain the most active sites toward electrophilic and nucleophilic reactions and propose a synthetic route to produce its fluorinated derivatives. The reactivity study allowed us to propose a late-stage synthetic route based on click chemistry to obtain three fluorinated MF-based derivatives. Molecular docking calculations suggested that the derivative F-propyl-MF could be suitable as PET radiopharmaceutical owing to the establishment of a five-coordinated complex with the catalytic Zn atom belonging to the active site of MMP-9, crucial factor in the inhibition of MMP-9.

One-Step Electropolymerization of a Dicyanobenzene-Carbazole-Imidazole Dye to Prepare Photoactive Redox Polymer Films.

To the best of our knowledge, this study reports the first direct electropolymerization of a dicyanobenzene-carbazole dye functionalized with an imidazole group to prepare redox- and photoactive porous organic polymer (POP) films in controlled amounts. The POP films were grown on indium-doped tin oxide (ITO) and carbon surfaces using a new monomer, 1-imidazole-2,4,6-tri(carbazol-9-yl)-3,5-dicyanobenzene (1, 3CzImIPN), through a simple one-step process. The structure and activities of the POP films were investigated as photoelectrodes for electrooxidations, as heterogeneous photocatalysts for photosynthetic olefin isomerizations, and for solid-state photoluminescence behavior tunable by lithium-ion concentrations in solution. The results demonstrate that the photoredox-POPs can be used as efficient photocatalysts, and they have potential applications in sensing.

Smart Polymeric Micelles for Anticancer Hydrophobic Drugs.

Cancer has become one of the deadliest diseases in our society. Surgery accompanied by subsequent chemotherapy is the treatment most used to prolong or save the patient's life. Still, it carries secondary risks such as infections and thrombosis and causes cytotoxic effects in healthy tissues. Using nanocarriers such as smart polymer micelles is a promising alternative to avoid or minimize these problems. These nanostructured systems will be able to encapsulate hydrophilic and hydrophobic drugs through modified copolymers with various functional groups such as carboxyls, amines, hydroxyls, etc. The release of the drug occurs due to the structural degradation of these copolymers when they are subjected to endogenous (pH, redox reactions, and enzymatic activity) and exogenous (temperature, ultrasound, light, magnetic and electric field) stimuli. We did a systematic review of the efficacy of smart polymeric micelles as nanocarriers for anticancer drugs (doxorubicin, paclitaxel, docetaxel, lapatinib, cisplatin, adriamycin, and curcumin). For this reason, we evaluate the influence of the synthesis methods and the physicochemical properties of these systems that subsequently allow an effective encapsulation and release of the drug. On the other hand, we demonstrate how computational chemistry will enable us to guide and optimize the design of these micelles to carry out better experimental work.

Explaining the interaction of mangiferin with MMP-9 and NF-ƙß: a computational study.

Mangiferin is a glycosylated xanthone widely distributed in nature, which exhibits wide pharmacological activities, highlighting its anti-cancer properties. Mangiferin interferes with inflammation, lipid, and calcium signaling, which selectively inhibits multiple NFkB target genes as interleukin-6, tumor necrosis factor, plasminogen, and matrix metalloproteinase, among others. In this work, the interactions of this polyphenol with MMP-9 and NF-κß are characterized by using computational chemistry methods. The results show MMP-9 inhibition by mangiferina is characterized for the interact with the catalytic Zn atom through a penta-coordinate structure. It is also demonstrated through a strong charge transfer established between mangiferin and Zn in the QM/MM study. Concerning the mangiferin/NF-κß system, the 92.3% of interactions between p50 sub-unity and DNA are maintained with a binding energy of - 8.04 kcal/mol. These findings indicate that mangiferin blocks the p50-p65/DNA interaction resulting in the loss of the functions of this hetero-dimeric member and suggesting inhibition of the cancer progression. Experimental results concerning the anti-cancer properties of mangiferin show that this natural compound can inhibit selectively MMP-9 and NF-ƙß. Although the anti-tumor properties of mangiferin are well defined, its molecular mechanisms of actions are not described. In this work, a computational study is carried out to characterize the interactions of mangiferin with these molecular targets. The results obtained corroborate the anti-proliferative and anti-apoptotic activity of mangiferin and provide a depiction of its mechanisms of action.

Ictal EEG in patients with autistic spectrum disorder and epilepsy.

OBJECTIVE: Autism spectrum disorder (ASD) is a neurodevelopmental disorder frequently associated with epilepsy and epilepsy is a leading cause of death in ASD patients. Despite growing interest in genetic, neurophysiological and clinical overlaps, data on ictal electroencephalographic (EEG) recordings in ASD are lacking since behavioral disorders often make it difficult to obtain EEG recordings. We examined ictal EEG features in a consecutive series of patients with ASD and epilepsy. METHODS: We retrospectively identified 400 consecutive patients with ASD and epilepsy at our Level 4 Epilepsy center between 2015 and 2019; 45 had at least one EEG-recorded seizure captured. Demographics, age of nonfebrile seizure onset, age of ASD diagnosis, language, magnetic resonance imagining findings, genetic testing and EEG studies were reviewed. Seizures were classified by semiologic and electrographic features. Ictal findings were analyzed. RESULTS: A total of 497 seizures were captured in 45 patients: 20 patients with focal onset epilepsy had 126 seizures (median: 1, range: 1-30), 17 patients with generalized onset epilepsy had 88 seizures (median: 2, range: 1-15), 7 patients with Lennox-Gastaut syndrome had 270 seizures (median: 12, range: 1-74) and one patient had both right hemisphere focal and generalized onsets (12 focal, 1 generalized). SIGNIFICANCE: Our study is the first to analyze a large set of ictal data in patients with autism spectrum disorder, a population traditionally difficult to obtain ictal recordings. Our results confirm the diverse spectrum of seizure types and provide clinical-EEG correlates of seizures in ASD patients. Both focal-onset and generalized-onset seizures were recorded, confirming that ASD patients have higher rates of both focal and generalized epilepsy syndromes. Among patients with focal epilepsy, temporal and frontal onsets were frequent, suggesting the possibility of epilepsy surgery or brain stimulation. EEG to classify seizures and epilepsies is critical to determine therapeutic options and effort should be made to obtain EEGs in this heterogenous population.

Development of an electronic nose to characterize odours emitted from different stages in a wastewater treatment plant.

Wastewater treatment plants have widely been described as a significant source of odour nuisance, which has led to an increase of neighbourhood complaints. Therefore, to mitigate the negative impact of odours, the detection and analysis of these emissions are required. This paper presents a measurement system based on an electronic nose for quantitative and qualitative odour analysis of samples collected from six different stages on a wastewater plant. Hence, two features vectors were performed in order to represent quantitative trends of the gaseous mixture sampled on the facility. In addition, odour fingerprints and a PCA were computed to discriminate odours from its sources and to detect relationships among the samples. This approach also comprises a dynamic dilution olfactometer. A PLS regression model was performed to predict the odour concentration by the electronic nose in term of odour units per cubic meter. The results show that the developed electronic nose is a promising and feasible instrument to characterize odours from wastewater plants.

Regioselective oxidation of phenols to o-quinones with o-iodoxybenzoic acid (IBX).

[reaction: see text] An efficient regioselective method for oxidation of phenols to o-quinones is reported. When this procedure is combined with a subsequent reduction, it proves to be useful for the construction of a variety of catechols.

Synthetic polymer nanoparticles with antibody-like affinity for a hydrophilic peptide.

Synthetic polymer nanoparticles with antibody-like affinity for a hydrophilic peptide have been prepared by inverse microemulsion polymerization. Peptide affinity was achieved in part by incorporating the target (imprint) peptide in the polymerization reaction mixture. Incorporation of the imprint peptide assists in the creation of complementary binding sites in the resulting polymer nanoparticle (NP). To orient the imprint peptide at the interface of the water and oil domains during polymerization, the peptide target was coupled with fatty acid chains of varying length. The peptide--NP binding affinities (ca. 90-900 nM) were quantitatively evaluated by a quartz crystal microbalance (QCM). The optimal chain length was established that created high affinity peptide binding sites on the surface of the nanoparticles. This method can be used for the preparation of nanosized synthetic polymers with antibody-like affinity for hydrophilic peptides and proteins ("plastic antibodies").