Retraction: Design and synthesis of magnetic Fe3O4@NFC-ImSalophCu nanocatalyst based on cellulose nanofibers as a new and highly efficient, reusable, stable and green catalyst for the synthesis of 1,2,3-triazoles.

[This retracts the article DOI: 10.1039/D0RA06251K.].

Retraction: Novel biocompatible core/shell Fe3O4@NFC@Co(ii) as a new catalyst in a multicomponent reaction: an efficient and sustainable methodology and novel reusable material for one-pot synthesis of 4H-pyran and pyranopyrazole in aqueous media.

[This retracts the article DOI: 10.1039/D0RA04698A.].

Retraction: Introduction of a trinuclear manganese(iii) catalyst on the surface of magnetic cellulose as an eco-benign, efficient and reusable novel heterogeneous catalyst for the multi-component synthesis of new derivatives of xanthene.

[This retracts the article DOI: 10.1039/D0RA09420J.].

Targeted delivery of elesclomol using a magnetic mesoporous platform improves prostate cancer treatment both in vitro and in vivo.

BACKGROUND: To improve the anticancer properties of elesclomol (ELC), targeted theranostic nanoparticles (NPs; APT-PEG-Au-MMNPs@ELC) were designed to increase the selectivity of the drug delivery system (DDS). MATERIALS AND METHODS: ELC was synthesized and entrapped in the open porous structure of magnetic mesoporous silica nanoparticles (MMNPs). The pore entrance of MMNPs was then blocked using gold gatekeepers. Finally, the external surfaces of the particles were grafted with functional polyethylene glycol (PEG) and EpCAM aptamer to generate biocompatible and targeted NPs. In the next step, the physicochemical properties of prepared NPs were fully evaluated and their anticancer potential was evaluated both in vitro and in vivo. RESULTS: The targeted NPs were successfully synthesized with a final size diameter of 81.13 ± 7.41 nm. The results indicated a pH-dependent release pattern, which sustained for 72 h despite an initial rapid release. Upon exposure to APT-PEG-Au-MMNPs@ELC, higher cytotoxicity was observed in human prostate cancer cells (PC-3) as compared with control Chinese hamster ovary (CHO) cells, indicating higher specificity of targeted NPs against EpCAM-positive cancerous cells. Moreover, APT-PEG-Au-MMNPs@ELC could induce apoptosis in PC-3 cells. In vivo results on a PC-3 xenograft tumor model demonstrated that targeted NPs could significantly inhibit tumor growth and diminish severe side effects of ELC, compared to the free drug. CONCLUSION: Collectively, APT-PEG-Au-MMNPs@ELC could be considered a promising theranostic platform for the targeted delivery of ELC to improve its therapeutic effects in prostate cancer.

Elesclomol, a copper-transporting therapeutic agent targeting mitochondria: from discovery to its novel applications.

Copper (Cu) is an essential element that is involved in a variety of biochemical processes. Both deficiency and accumulation of Cu are associated with various diseases; and a high amount of accumulated Cu in cells can be fatal. The production of reactive oxygen species (ROS), oxidative stress, and cuproptosis are among the proposed mechanisms of copper toxicity at high concentrations. Elesclomol (ELC) is a mitochondrion-targeting agent discovered for the treatment of solid tumors. In this review, we summarize the synthesis of this drug, its mechanisms of action, and the current status of its applications in the treatment of various diseases such as cancer, tuberculosis, SARS-CoV-2 infection, and other copper-associated disorders. We also provide some detailed information about future directions to improve its clinical performance.

Understanding the effects of building block rings of π electron-rich organic photocatalysts in CO2 transformation to amino acids.

Understanding the effective factors in the performance of some Oligo (p-phenylenes) (OPPs) and Polycyclic Aromatic Hydrocarbons (PAHs), as efficient organocatalysts in photocatalytic CO2 transformations are the main goals of this investigation. The studies are based on density functional theory (DFT) calculations on the mechanistic aspects of C-C bond formation through a coupling reaction between CO2•- and amine radical. The reaction is performed through two successive single electron transfer steps. After careful kinetic investigations by Marcus' theory rules, powerful descriptors are used to describe the behavior of observed barrier energies of electron transfer steps. The studied PAHs and OPPs consist of different numbers of rings. Thus, it can be considered different charge densities, afforded from π electrons, of PAHs and OPPs that cause distinguished efficiency in kinetic aspects of electron transfer steps. Electrostatic Surface Potential (ESP) analyses reveal a good relationship between the charge density of the studied organocatalysts in single electron transfer (SET) steps and the kinetic parameters of the steps. Moreover, the contribution of rings in the framework of PAHs and OPPs would be another effective factor in the barrier energies of SET steps. Aromatic properties of the rings, studied by the Anisotropy of the Current-Induced Density (ACID), Nucleus-Independent Chemical Shift (NICS), the multi-center bond order (MCBO), and AV1245 Indexes, are the other impressive factors in the role of rings in SET steps. The results show that the aromatic properties of the rings are not similar to each other. Higher aromaticity affords remarkable reluctance of the corresponding ring to participate in SET steps.

Energy and environmental investigation on photovoltaic system performance by application of square cross-sectional two-phase closed thermosyphon.

By increasing solar radiation, the temperature of photovoltaic cells rises, and as a result, the electrical power and lifespan of the panel are reduced. By cooling the panel with two-phase closed thermosyphons (TPCTs), this effect can be minimized. In contrast to typical TPCT, which has a circular cross-section, the thermosyphon used in this study has a square cross-section. In the proposed system, the solar cells place on an aluminum plate to reduce the thermal resistance and improve the heat transfer rate. Investigations have been made on the effects of three different filling ratios, including 25, 45, and 65%. The trial results show that equipped PV panel with square TPCT with a filling ratio of 45% produces the best cooling performance. In this instance, 68.31 kJ of heat energy was transmitted to the tank water. Electrically, the equipped panel has been found to produce up to 3.85% greater output power than a conventional one. A new mathematical model to estimate the performance of equipped PV panel with square TPCT is introduced too. Additionally, the research has looked into how varied tank volumes, solar radiation, and wind velocity affect the temperature difference in tank water. Based on environmental investigations, the proposed solar system is used instead of natural gas and fuel oil, it will prevent the annual emission of 106.3 and 159.4 kg of CO2 per unit area of the panel to atmosphere.

Synthesis of double-shelled periodic mesoporous organosilica nanospheres/MIL-88A-Fe composite and its elevated performance for Pb2+ removal in water.

Herein, we report the synthesis of double-shelled periodic mesoporous organosilica nanospheres/MIL-88A-Fe (DSS/MIL-88A-Fe) composite through a hydrothermal method. To survey the structural and compositional features of the synthesized composite, a variety of spectroscopic and microscopic techniques, including FT-IR, XRD, BET, TEM, FE-SEM, EDX, and EDX-mapping, have been employed. A noteworthy point in this synthesis procedure is the integration of MOF with PMO to increase the adsorbent performance, such as higher specific surface area and more active sites. This combination leads to achieving a structure with an average size of 280 nm and 1.1 µm long attributed to DSS and MOF, respectively, microporous structure and relatively large specific surface area (312.87 m2/g). The as-prepared composite could be used as an effective adsorbent with a high adsorption capacity (250 mg/g) and quick adsorption time (30 min) for the removal of Pb2+ from water. Importantly, DSS/MIL-88A-Fe composite revealed acceptable recycling and stability, since the performance in Pb2+ removal from water remained above 70% even after 4 consecutive cycles.

Designing a new method for growing metal-organic framework (MOF) on MOF: synthesis, characterization and catalytic applications.

Metal-organic frameworks as a unique class of high-surface-area materials have gained considerable attention due to their characteristic properties. In this perspective, herein, we report an eco-friendly and inexpensive route for the synthesis of 4(3H)-quinazolinones using magnetically separable core-shell-like bimetallic Fe3O4-MAA@Co-MOF@Cu-MOF NPs as environmentally-friendly heterogeneous catalysts. To the best of our knowledge, this is the first example of the integration of two different types of MOFs, which contain two different metal ions (Co2+ in the core and Cu2+ in the shell) using an external ligand. Our study not only introduces a novel nanostructured catalyst for the organic reaction but also presents a new strategy for the combination of two MOFs in one particle at the nanometer level. To survey the structural and compositional features of the synthesized nanocatalyst, a variety of spectroscopic and microscopic techniques including FT-IR, XRD, BET, TEM, HR-TEM, FE-SEM, EDX, EDX-mapping, TGA, VSM, and ICP-OES were employed. The combination of magnetic Co-MOF with Cu-MOF leads to achieving unique structural and compositional properties for Fe3O4-MAA@Co-MOF@Cu-MOF NPs with a particle size of 20-70 nm, mesostructure, and relatively large specific surface area (236.16 m2 g-1). The as-prepared nanostructured catalyst can be an excellent environment catalyst for the synthesis of a wide library of 4(3H)-quinazolinones derivatives, including electron-donating and electron-withdrawing aromatic, heteroaromatic, and aliphatic compounds under solvent-free conditions much better than the parent precursors. Moreover, by investigating the longevity of the nanocatalyst, the conclusion could be derived that the aforesaid nanocatalyst is stable under reaction conditions and could be recycled for at least seven recycle runs without a discernible decrease in its catalytic activity.

Immobilized Cu(0) nanoparticles on montmorillonite-modified with benzalkonium chloride (MMT-BAC@Cu(0)): as an eco-friendly and proficient heterogeneous nano-catalyst for green synthesis of 5-substituted 1H-tetrazoles.

In this study, Cu(0) nanoparticles supported on organo-modified montmorillonite with benzalkonium chloride (MMT-BAC@Cu(0)) were synthesized and used as an eco-friendly and green heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles in mild media. The structure of the catalyst was investigated using various techniques including XRD, EDX, ICP, TEM, FE-SEM, and FT-IR. The advantages of availability, low cost, non-toxicity, and biocompatibility of clay were our focus in synthesizing this nanoclay catalyst. The method's advantages include good to excellent product yields, mild conditions, easy work-up, short reaction times, and easy reuse of the nanocatalyst.

Surface modification of gold nanoparticles with 6-mercapto-1-hexanol to facilitate dual conjugation of protoporphyrin IX and folic acid for improving the targeted photochemical internalization.

Objectives: Photochemical internalization (PCI) is an important type of photodynamic therapy for delivering macromolecules into the cytosol by the endocytosis process. In this study, 6-mercapto-1-hexanol (MH) was used to functionalize the gold nanostructure as a primer for surface modification to improve conjugation of multi-agents such as protoporphyrin IX (Pp-IX) and folic acid with gold nanoparticles (PpIX/FA-MH-AuNP) to facilitate the photochemical internalization. Materials and Methods: After surface modification of AuNPs with MH, PpIX and FA are bonded to the surface of the MH-AuNPs through the coupling reaction to produce the desired conjugated AuNPs. In the next step, the synthesized nanostructures were characterized by different methods. Finally, after selecting specific concentrations, light treatments were applied and cell survival was measured based on MTT analysis. Also, in order to better study the morphology of the cells, they were stained by the Giemsa method. The SPSS 16 software was used for data analysis. Results: By surface modification of the nanostructure with MH and then conjugation of FA to it, the incubation time of the drug in PpIX/FA-MH-AuNP was reduced from 3 hr to 30 min. Also, at each light dose, cell death in the presence of PpIX/FA-MH-AuNP was significantly reduced compared with unconjugated conditions (P<0.001). Under these conditions, the ED50 for PpIX and PpIX-MH-AuNP and PpIX/FA-MH-AuNP at a concentration of 2.5 µg/ml is 8.9, 9.1, and 6.17 min, respectively. Conclusion: The results show that the PCI of PpIX/FA-MH-AuNP increases the selective phototoxicity efficiency on cancer cells compared with the conventional process of photodynamic therapy.

Nitronium salts as mild and inexpensive oxidizing reagents toward designing efficient strategies in organic syntheses; A mechanistic investigation based on the DFT insights.

Today, introducing and evaluating the performance of novel reagents are an undeniable part of designing a successful synthetic strategy. Herein, we study the efficiency and mechanism of recently synthesized nitronium salts (e.g., NO2FSO3, NO2CF3SO3, NO2HS2O7, NO2BF4, NO2PF6, and NO2HSO4) in the oxidation reaction of ethanol to acetic acid, as a model of the primary alcohol transformations to linear carboxylic acid. An aldehyde molecule is the first produced species in this reaction which is converted to the acetic acid molecule in the presence of in situ-produced nitric acid. Concerning the proposed mechanism, among the studied nitronium salts, two different behaviors can be observed in the transition state of the step in which the aldehyde molecule is formed. The calculated barrier energies of this step have been scrutinized by powerful descriptors such as Quantum Theory of Atoms in Molecules (QTAIM), Natural Bond Orbital (NBO), Electrostatic Potential (ESP) surfaces, and Activation Strain Model (ASM). The outcomes of the studied descriptors illustrate that nitronium salts have different performances in progressing the formation of the aldehyde molecule. Indeed, the likeness of the transition state of this step to the products for NO2FSO3, NO2CF3SO3, and NO2HS2O7 species is more significant than the others. Accordingly, these reagents have more potential to apply as oxidizing agents in the primary alcohol transformations to linear carboxylic acid.

Conversion of 2D MXene to Multi-Low-Dimensional GerMXene Superlattice Heterostructure.

Integration of 2D structures into other low-dimensional materials results in the development of distinct van der Waals heterostructures (vdWHSs) with enhanced properties. However, obtaining 2D-1D-0D vdWHSs of technologically useful next generation materials, transition-metal carbide MXene and monoelemental Xene nanosheets in a single superlattice heterostructure is still challenging. Here, the fabrication of a new multidimensional superlattice heterostructure "GerMXene" from exfoliated M3X2T x MXene and hydrogenated germanane (GeH) crystals, is reported. Direct experimental evidence for conversion of hydrothermally activated titanium carbide MXene (A-MXene) to GerMXene heterostructure through the rapid and spontaneous formation of titanium germanide (TiGe2 and Ti6Ge5) bonds, is provided. The obtained GerMXene heterostructure possesses enhanced surface properties, aqueous dispersibility, and Dirac signature of embedded GeH nanosheets as well as quantum dots. GerMXene exhibits functional bioactivity, electrical conductivity, and negative surface charge, paving ways for its applications in biomedical field, electronics, and energy storage.

Synthesis of functionalized pyrrole derivatives via diverse cyclization of azomethine ylide and olefins.

The azomethine ylides are generally used in 1,3-dipolar cycloadditions with various dipolarophiles. In this work, a new and diverse route has been developed for the azomethine ylides, for synthesis of novel pyrrole derivatives. The azomethine ylide, produced via C-H activation of unreactive C(sp3)-H bond of 2-methylquinoline, by molecular iodine, in the presence of pyridine. Herein, we represent novel pyrrole derivatives, synthesized from the reaction of pyridinium ylide with olefins, which formed via a reaction of isatin, dialkyl acetylenedicarboxylate derivatives and pyridine as a base in moderate to excellent yields. Various features of this cyclization, discussed.

Cell-free extract assisted synthesis of ZnO nanoparticles using aquatic bacterial strains: Biological activities and toxicological evaluation.

The introduction of novel bacterial strains and the development of microbial approaches for nanoparticles biosynthesis could minimize the negative environmental impact and eliminate the concern and challenges of the available approaches. In this study, a biological method based on microbial cell-free extract was used for biosynthesis of ZnO NPs using two new aquatic bacteria, Marinobacter sp. 2C8 and Vibrio sp. VLA. The synthesized ZnO NPs were characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscope (AFM), dynamic light scattering (DLS) and zeta potential. The UV-Visible absorption peak was found to be at 266 and 250 nm for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. FTIR study suggested that the hydroxyl, amine, and carboxyl groups of bacterial proteins are mainly responsible for stabilizing the biosynthesized ZnO NPs. The formation of hexagonal wurtzite structure of ZnO NPs was confirmed by the XRD pattern. The morphology of the nanoparticles was found to be spherical with the average particle size of about 10.23 ± 2.48 nm and 20.26 ± 4.44 nm for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. The values of zeta potential indicate the high stability of the biosynthesized ZnO NP. Zeta potential values indicated the high stability of the biosynthesized ZnO NP and were obtained -20.54 ± 7.15 and -23.87 ± 2.29 mV for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. The biosynthesized ZnO NPs had antibacterial activity against Gram-negative and Gram-positive strains and possessed excellent antibiofilm activity with the maximum inhibition of about 96.55% at 250 µg/mL. The DPPH activity of ZnO-2C8 NPs and ZnO-VLA NPs were found 88.9% and 85.7% for 2500 µg/mL concentration, respectively. The toxicity test revealed the biocompatibility of the biosynthesized ZnO NPs. The results suggested that this approach is a very good route for synthesizing ZnO NPs with potential applications in biotechnology.

Introduction of a trinuclear manganese(iii) catalyst on the surface of magnetic cellulose as an eco-benign, efficient and reusable novel heterogeneous catalyst for the multi-component synthesis of new derivatives of xanthene.

In this work, the new trinuclear manganese catalyst defined as Fe3O4@NFC@NNSM-Mn(iii) was successfully manufactured and fully characterized by different techniques, including FT-IR, XRD, TEM, SEM, EDX, VSM, and ICP analysis. There have been reports of the use of magnetic catalysts for the synthesis of xanthine derivatives. The critical potential interest in the present method include short reaction time, high yields, recyclability of the catalyst, easy workup, and the ability to sustain a variety of functional groups, which give economical as well as ecological rewards. Also, the synthesized catalyst was used as a recyclable trinuclear catalyst in alcohol oxidation reactions at 40 °C. The magnetic catalyst activity of Fe3O4@NFC@NNSM-Mn(iii) could be attributed to the synergistic effects of the catalyst Fe3O4@NFC@NNS-Mn(iii) with melamine. Employing a sustainable and safe low temperature, using an eco-friendly solvent, no need to use any additive, and long-term stability and magnetic recyclability of the catalyst for at least six successive runs are the advantages of the current protocol towards green chemistry. This protocol is a benign, environmentally friendly method for heterocycle synthesis.

Allylphenols as a new class of human 15-lipoxygenase-1 inhibitors.

In this study, a series of mono- and diallylphenol derivative were designed, synthesized, and evaluated as potential human 15-lipoxygenase-1 (15-hLOX-1) inhibitors. Radical scavenging potency of the synthetic allylphenol derivatives was assessed and the results were in accordance with lipoxygenase (LOX) inhibition potency. It was found that the electronic natures of allyl moiety and para substituents play the main role in radical scavenging activity and subsequently LOX inhibition potency of the synthetic inhibitors. Among the synthetic compounds, 2,6-diallyl-4-(hexyloxy)phenol (42) and 2,6-diallyl-4-aminophenol (47) showed the best results for LOX inhibition (IC50 = 0.88 and 0.80 µM, respectively).

Prevalence and Correlates of Mental Health Status Among Pre-Hospital Healthcare Staff.

INTRODUCTION: Mental stress amongst pre-hospital Emergency Medical Services (EMS) workers is an iceberg phenomenon; owing to unique occupational stressors faced by them. This study was aimed to examine the mental health status of pre-hospital EMS workers and its correlation with Post-Traumatic Stress Disorder (PTSD) and Work Environment Scale (WES). METHODS: This cross-sectional study incorporated 224 emergency EMS members from urban and road EMS bases in eastern Iran in 2018. General Health Questionnaire (GHQ-28), Post-Traumatic Stress Disorder Checklist-Civilian version (PTSD-C), and Work Environment Scale (WES) were used as research instruments. Data were analyzed via SPSS Statistics software (version 21); while p<0.05 was considered significant. RESULTS: The mean age of participants was 31.91±6.9 years; 36(16.1%) had PTSD ≥50, which increased with age (p-0.01), number of offspring (p-0.022) and time working at the EMS (p-0.002). Mean WES scores were 73.41±12.27; with a significant impact of marital status (p-0.007), the number of offspring (p-0.023), qualification (p-0.019) and less time working at the EMS (p-0.008). Mental distress was recorded in 89(39.7%) individuals. Multivariate logistic regression revealed that members at higher risk of mental distress were; those with associate's degree (adjusted OR 3.192; 95% CI, 1.456-6.998), individuals with 1 or 2 offspring (adjusted OR 2.03; 95% CI, 0.992-4.156; adjusted OR 3.380; 95% CI, 1.483-7.704, respectively), and those with PTSD equal or higher than 50 (adjusted OR 2.504; 95% CI, 1.063-5.903), with a reverse impact of WES (p>0.05). CONCLUSION: PTSD adversely affected mental health and clinical performance of the subjects; while work-place environment augmented working spirit as well as psychological resilience. Strategies aiming at stress-dilution and improvements in a professional environment cannot be over-emphasized.

Comparative evaluation of silver nanoparticles biosynthesis by two cold-tolerant Streptomyces strains and their biological activities.

The present study reflected on high-priority biological activities of novel silver nanoparticles (AgNPs) synthesized via two cold-tolerant strains; namely, Streptomyces sp.OSIP1 and Streptomyces sp.OSNP14. These AgNPs were synthesized through a green method using culture supernatant of bacteria at 20 °C and characterized by several instrumental techniques. The TEM results revealed that the NPs obtained from OSIP1 were smaller (8 nm, average) than those taken from OSIP14 (15 nm, average). Both AgNPs-OSP1 and AgNPs-OSNP14 also posed the strongest growth inhibitory effect against several pathogenic bacteria alone and especially in combination with antibiotics. Smaller NPs especially at 3.9-31.25 µg/ml concentrations were assumed more effective biofilm inhibitors of Pseudomonas aeruginosa. Cytotoxic activity of both AgNPs (at 25 and 50 µg/mL concentrations) on mouse colorectal carcinoma cells (CT26) were then studied using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The findings demonstrated that smaller AgNPs at a 50 µg/mL concentration had 7% more cytotoxicity effects. In conclusion; although AgNPs produced by diverse strains of cold-adapted Streptomyces had close characteristics and biological activities, they showed some multifarious properties.

Exploring the potentials of halophilic prokaryotes from a solar saltern for synthesizing nanoparticles: The case of silver and selenium.

Halophiles are the organisms that thrive in extreme high salt environments. Despite the extensive studies on their biotechnological potentials, the ability of halophilic prokaryotes for the synthesis of nanoparticles has remained understudied. In this study, the archaeal and bacterial halophiles from a solar saltern were investigated for the intracellular/extracellular synthesis of silver and selenium nanoparticles. Silver nanoparticles were produced by the archaeal Haloferax sp. (AgNP-A, intracellular) and the bacterial Halomonas sp. (AgNP-B, extracellular), while the intracellular selenium nanoparticles were produced by the archaeal Halogeometricum sp. (SeNP-A) and the bacterial Bacillus sp. (SeNP-B). The nanoparticles were characterized by various techniques including UV-Vis spectroscopy, XRD, DLS, ICP-OES, Zeta potentials, FTIR, EDX, SEM, and TEM. The average particle size of AgNP-A and AgNP-B was 26.34 nm and 22 nm based on TEM analysis. Also, the characteristic Bragg peaks of face-centered cubic with crystallite domain sizes of 13.01 nm and 6.13 nm were observed in XRD analysis, respectively. Crystallographic characterization of SeNP-A and SeNP-B strains showed a hexagonal crystallite structure with domain sizes of 30.63 nm and 29.48 nm and average sizes of 111.6 nm and 141.6 nm according to TEM analysis, respectively. The polydispersity index of AgNP-A, AgNP-B, SeNP-A, and SeNP-B was determined as 0.26, 0.28, 0.27, and 0.36 and revealed high uniformity of the nanoparticles. All of the synthesized nanoparticles were stable and their zeta potentials were calculated as (mV): -33.12, -35.9, -31.2, and -29.34 for AgNP-A, AgNP-B, SeNP-A, and SeNP-B, respectively. The nanoparticles showed the antibacterial activity against various bacterial pathogens. The results of this study suggested that the (extremely) halophilic prokaryotes have great potentials for the green synthesis of nanoparticles.