Expression of concern: Facile route to synthesize Fe3O4@acacia-SO3H nanocomposite as a heterogeneous magnetic system for catalytic applications.

Expression of concern for 'Facile route to synthesize Fe3O4@acacia-SO3H nanocomposite as a heterogeneous magnetic system for catalytic applications' by Reza Taheri-Ledari et al., RSC Adv., 2020, 10, 40055-40067, https://doi.org/10.1039/D0RA07986C.

Fe3O4@Gum Arabic modified polyvinyl chloride membranes to improve antifouling performance and separation efficiency of organic pollutants.

Nanofiltration (NF) membranes are promising media for water and wastewater treatment; however, they suffer from their hydrophobic nature and low permeability. For this reason, the polyvinyl chloride (PVC) NF membrane was modified by iron (III) oxide@Gum Arabic (Fe3O4@GA) nanocomposite. First, Fe3O4@GA nanocomposite was synthesized by the co-precipitation approach and then its morphology, elemental composition, thermal stability, and functional groups were characterized by various analyses. Next, the prepared nanocomposite was added to the casting solution of the PVC membrane. The bare and modified membranes were fabricated by a nonsolvent-induced phase separation (NIPS) method. The characteristics of fabricated membranes were assessed by mechanical strength, water contact angle, pore size, and porosity measurements. The optimum Fe3O4@GA/PVC membrane had a 52 L m-2. h-1. bar-1 water flux with a high flux recovery ratio (FRR) value (82%). Also, the filtration experiment exhibited that the Fe3O4@GA/PVC membrane could remarkably remove organic contaminants, achieving high rejection rates of 98% Reactive Red-195, 95% Reactive Blue-19, and 96% Rifampicin antibiotic by 0.25 wt% of Fe3O4@GA/PVC membrane. According to the results, adding Fe3O4@GA green nanocomposite to the membrane casting solution is a suitable and efficient procedure for modifying NF membranes.

Recent advances on biomedical applications of pectin-containing biomaterials.

There is a growing demand for biomaterials developing with novel properties for biomedical applications hence, hydrogels with 3D crosslinked polymeric structures obtained from natural polymers have been deeply inspected in this field. Pectin a unique biopolymer found in the cell walls of fruits and vegetables is extensively used in the pharmaceutical, food, and textile industries due to its ability to form a thick gel-like solution. Considering biocompatibility, biodegradability, easy gelling capability, and facile manipulation of pectin-based biomaterials; they have been thoroughly investigated for various potential biomedical applications including drug delivery, wound healing, tissue engineering, creation of implantable devices, and skin-care products.

Magnetic dextrin nanobiomaterial: An organic-inorganic hybrid catalyst for the synthesis of biologically active polyhydroquinoline derivatives by asymmetric Hantzsch reaction.

Dextrin is a low molecular weight polysaccharide obtained from natural resources. Due to exceptional properties such as chemical structure, having extreme reactive functional groups, low cost, commercial availability, non-toxicity and biocompatibility, it can be introduced as a green organocatalyst. The fabrication of hybrid materials from natural polymers and synthetic inorganic materials constructs compounds with new features, abilities and applications. Therefore, magnetic dextrin nanobiocomposite was prepared using a simple chemical co-precipitation. Then, it was characterized by Fourier transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray (EDX) analysis, vibrating sample magnetometer (VSM) curve, scanning electron microscopy (SEM) image, X-ray diffraction (XRD) pattern, thermogravimetric analysis (TGA) and inductively-coupled plasma atomic emission spectroscopy (ICP-AES) analysis. Subsequently, to evaluate the catalytic performance of the synthetic hybrid catalyst, it was tested for the synthesis of biologically active polyhydroquinoline derivatives by four-component condensation reactions of aromatic aldehyde, ethyl acetoacetate, dimedone, ammonium acetate in ethanol under refluxing conditions. Experimental observations indicated some advantages of the present method, such as the use of green and biopolymer-based catalyst, simple procedure, mild reaction conditions, short reaction times (15-45 min), appropriate yield of products (70-95%) and catalyst reusability after five consecutive runs without considerable catalytic performance decrease.

Facile route to synthesize Fe3O4@acacia-SO3H nanocomposite as a heterogeneous magnetic system for catalytic applications.

In this work, a novel catalytic system for facilitating the organic multicomponent synthesis of 9-phenyl hexahydroacridine pharmaceutical derivatives is reported. Concisely, this catalyst was constructed from acacia gum (gum arabic) as a natural polymeric base, iron oxide magnetic nanoparticles (Fe3O4 NPs), and sulfone functional groups on the surface as the main active catalytic sites. Herein, a convenient preparation method for this nanoscale composite is introduced. Then, essential characterization methods such as various spectroscopic analyses and electron microscopy (EM) were performed on the fabricated nano-powder. The thermal stability and magnetic properties were also precisely monitored via thermogravimetric analysis (TGA) and vibrating-sample magnetometry (VSM) methods. Then, the performance of the presented catalytic system (Fe3O4@acacia-SO3H) was further investigated in the referred organic reaction by using various derivatives of the components involved in the reaction. Optimization, mechanistic studies, and reusability screening were carried out for this efficient catalyst as well. Overall, remarkable reaction yields (94%) were obtained for the various produced derivatives of 9-phenyl hexahydroacridine in the indicated optimal conditions.

A brief survey on the advanced brain drug administration by nanoscale carriers: With a particular focus on AChE reactivators.

Obviously, delivery of the medications to the brain is more difficult than other tissues due to the existence of a strong obstacle, which is called blood-brain barrier (BBB). Because of the lipophilic nature of this barrier, it would be a complex (and in many cases impossible) process to cross the medications with hydrophilic behavior from BBB and deliver them to the brain. Thus, novel intricate drug-carriers in nano scales have been recently developed and suitably applied for this purpose. One of the most important categories of these hydrophilic medications, are reactivators for acetyl cholinesterase (AChE) enzyme that facilitates the breakdown of acetylcholine (as a neurotransmitter). The AChE function is inhibited by organophosphorus (OP) nerve agents that are extremely used in military conflicts. In this review, the abilities of the nanosized drug delivery systems to perform as suitable vehicles for AChE reactivators are comprehensively discussed.