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Abstract The optical, photoluminescence, and electrical properties of Poly(Z)-PTI and Poly(E)-PTI, two Poly-Pyrrol-Thiazol-Imine polymers with comparable chemical structures but distinct configurations, were examined. Using the dip-casting method, polymer films were deposited on ITO substrates. UV-VIS spectroscopy revealed that both polymers diverged between 500 and 800 nm, showing the impact of molecular arrangement, but showed similar absorption behavior for wavelengths shorter than 500 nm. For Poly(Z)-PTI, the direct optical energy gaps were 2.06 eV, while for Poly(E)-PTI, they were 1.78 eV. Poly(Z)-PTI displayed an emission peak at 610 nm (red) according to laser photoluminescence spectra, while Poly(E)-PTI peaked at 563 nm (green-yellow). The capacitance behavior was revealed by electrochemical impedance spectroscopy. Nyquist plots suggested an equivalent circuit model of Rs (CRct)(QR)(CR) for both polymers, and the relaxation times were 15.9 ns for Poly(Z)-PTI and 89.5 ns for Poly(E)-PTI. The Mott-Schottky analysis verified the n-type conductivity, revealing 2.18 × 1016 cm− 3 carrier densities for Poly(Z)-PTI and 1.78 × 1016 cm− 3 for Poly(E)-PTI. At lower frequencies, both polymers exhibited limited conductivity and large dielectric constants. Insights into the possible uses of Poly-Pyrrol-Thiazol-Imine polymers in electrical and optoelectronic devices are provided by this study, which emphasizes the influence of molecular configuration on these polymers’ characteristics.

Abstract Background Cancer, a leading cause of mortality worldwide, continues to pose significant challenges in treatment and management. Conventional therapies often face limitations, including lack of selectivity, adverse effects, and the development of resistance mechanisms. Methods Therefore, this study aims to investigate nanocellulose, nanoselenium, and their nanocomposite which are previously synthesized and characterized. Molecular docking simulations were performed to assess binding affinity to malate dehydrogenase-1 (MDH-1), a key metabolic enzyme in cancer cells. Cytotoxicity was evaluated in A549 lung cancer cell line, the MCF-7 breast cancer cell line, and the WI-38 normal cell line. Mechanistic studies included assessment of MDH-1 activity and expression, intracellular reactive oxygen species (ROS) levels, and cell cycle analysis. Results Molecular docking simulations demonstrated a favorable binding affinity (136.98 kcal/mol) of cellulose and selenium as cofactor to the nicotinamide adenine dinucleotide (NAD) + hydrogen (H) (NADH) binding domain of human MDH-1. The nanocomposite exhibited a synergistic impact against cancer, causing a considerable decrease in the viability of MCF-7 cells compared to separate treatments with nanocellulose and nanoselenium. Moreover, it showed negligible toxicity towards normal cells. Biochemical studies demonstrated that nanocellulose, nanoselenium and the nanocomposite substantially reduced MDH-1 activity and messenger ribonucleic acid (mRNA) expression in MCF-7 cells. This was confirmed by flow cytometric analysis, which revealed that the nanocomposite could effectively reduce the intracellular ROS levels and induce potent cell cycle arrest in the G0/G1 phase, that inhibit MCF-7 cell proliferation. Conclusions In conclusion, our finding elucidated the promising therapeutic potential of nanocellulose, nanoselenium, and their nanocomposite as effective anticancer agents in breast cancer treatment, demanding further preclinical and clinical investigations to explain their mechanisms of action.

Vanillin loaded-physically crosslinked hydrogel membranes made of PVA/chitosan/itaconic acid (PVA-CS-IA) were prepared using freezing-thawing (F-T) cycle method. To ensure the entanglement of PVA-CS-IA chains, three F-T cycles were repeated. The polymeric chains entanglements were confirmed and characterized by different instrumental characterizations. Physicochemical properties for example, swelling ratio, mechanical characteristics, gel fraction percentage (GF%), hydrolytic degradation, and thermal stability of PVA-CS-IA membrane were discussed in detail. The findings showed that the swelling ratio, mechanical characteristics, and hydrolytic degradation of the crosslinked membranes enhanced with increasing CS-IA contents in membranes composition; however, GF% gradually declined with CS-IA content. Additionally, cell viability test using HFB-4 cell line and antimicrobial activity against Staphylococcus aureus and Escherichia coli were evaluated using MTT assay and the bacterium growth inhibition percentage method; respectively. Notably, with varying incubation durations and membrane concentrations, all examined constructed hydrogels showed significant cell survival percentages. The findings supported the notion that produced hydrogel membranes might be used in a professional setting as antibacterial dressings or biomaterials for quick wound healing rate.

Abstract Poly l(+) lactic acid (PLLA) has become crucial in the biomedical industry for various uses. The direct polycondensation method was used to prepare Poly l(+) Lactic Acid (PLLA). Different catalysts, including metal oxides and metal halides, were used to test the polymerization technique. The effect of the amount of catalysts and the type of coupling agent were investigated. The effect of reaction time and polymerization solvents was also studied. PLLA was loaded with isosorbide dinitrate utilizing the solvent evaporation process. The synthesized polymer-drug system was evaluated by different means such as FT-IR, TGA, DSC, XRD, entrapment efficiency (E.E), drug loading (D.L), particle size analysis, and zeta potential determination. Studies on in-vitro release using UV light at 227 nm at various pH levels were conducted, and the kinetics of release and cytotoxicity using the sulforhodamine B (SRB) assay on human skin fibroblast cells were examined.

Abstract Nanofibers and mat-like polyacrylonitrile-polyphenyl/titanium oxide (PAN-Pph./TiO2) with proper electrochemical properties were fabricated via a single-step electrospinning technique for supercapacitor application. Scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), thermogravimetry (TGA), fourier transform infrared (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) were conducted to characterize the morphological and chemical composition of all fabricated nanofibers. Furthermore, the electrochemical activity of the fabricated nanofibers for energy storage applications (supercapacitor) was probed by cyclic voltammetry (CV), charge–discharge (CD), and electrochemical impedance spectroscopy (EIS). The PAN-PPh./TiO2 nanofiber electrode revealed a proper specific capacitance of 484 F g−1 at a current density of 11.0 A g–1 compared with PAN (198 F g−1), and PAN-PPh. (352 F g−1) nanofibers using the charge–discharge technique. Furthermore, the PAN-PPh./TiO2 nanofiber electrode displayed a proper energy density of 16.8 Wh kg−1 at a power density (P) of 2749.1 Wkg−1. Moreover, the PAN-PPh./TiO2 nanofiber electrode has a low electrical resistance of 23.72 Ω, and outstanding cycling stability of 79.38% capacitance retention after 3000 cycles.

Abstract Background Melanin is a natural pigment that is considered a promising biomaterial for numerous biotechnological applications across several industries. Melanin has biomedical applications as antimicrobial, anticancer, and antioxidant properties. Additionally, in the pharmaceutical and cosmetic industries, it is used in drug delivery and as a radioprotective agent. Also, melanin has environmental uses in the fields of bioremediation and the food industry. The biosynthesis of melanin pigment is an area of interest for researchers due to its multifunctionality, high compatibility, and biodegradability. Therefore, our present work is the first attempt to characterize and optimize the productivity of melanin pigment from Streptomyces djakartensis NSS-3 concerning its radioprotection and biological properties. Results Forty isolates of soil actinobacteria were isolated from the Wadi Allaqui Biosphere Reserve, Egypt. Only one isolate, ACT3, produced a dark brown melanin pigment extracellularly. This isolate was identified according to phenotypic properties and molecular phylogenetic analysis as Streptomyces djakartensis NSS-3 with accession number OP912881. Plackett–Burman experimental design (PBD) and response surface methodology (RSM) using a Box-Behnken design (BBD) were performed for optimum medium and culturing conditions for maximum pigment production, resulting in a 4.19-fold improvement in melanin production (118.73 mg/10 mL). The extracted melanin pigment was purified and characterized as belonging to nitrogen-free pyomelanin based on ultraviolet–visible spectrophotometry (UV–VIS), Fourier transform infrared (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and NMR studies. Purified melanin demonstrated potent scavenging activity with IC50 values of 18.03 µg/mL and revealed high potency as sunscreens (in vitro SPF = 18.5). Moreover, it showed a nontoxic effect on a normal cell line (WI38), while it had a concentration-dependent anticancer effect on HCT116, HEPG, and MCF7 cell lines with IC50 = 108.9, 43.83, and 81.99 µg/mL, respectively. Also, purified melanin had a detrimental effect on the tested MDR bacterial strains, of which PA-09 and SA-04 were clearly more susceptible to melanin compared with other strains with MICs of 6.25 and 25 µg/mL, respectively. Conclusion Our results demonstrated that the newly characterized pyomelanin from Streptomyces djakartensis NSS-3 has valuable biological properties due to its potential photoprotective, antioxidant, anticancer, antimicrobial, and lack of cytotoxic activities, which open up new prospects for using this natural melanin pigment in various biotechnological applications and avoiding chemical-based drugs.

Abstract The condensation of pyrrole-2,5-dicarbaldehyde (1) with 5-(2-amino-4-phenylthiazol-5-yl)-4-phenylthiazol-2-amine (2) and/or 5-(4-Amino-phenyl)-4-phenylthiazol-2-amine (3) gave new poly(Z)-N-((5-(iminomethyl)-1H-pyrrol-2-yl)methylene)-5-(2-((E)-(5-(iminomethyl)-I-pyrrol-2-yl)methyleneamino)-4-phenylthiazol-5-yl)-4-phenylthiaol-2-amine (P1) and/or poly(E)-N-((5-(iminomethyl)-1H-pyrrol-2-yl)methylene)-5-(4-((E)-(5-(iminomethyl)-1H-pyrrol-2-yl)methyleneamino)phenyl)-4-phenylthiaol-2-amine (P2) as a novel conjugated polymer by microwave irradiation and traditional heating.. It is evident that the microwave irradiation technique quickly raised the molecular weight of polyimines. In addition to quantifying the molecular weight of the resultant polyimines. All the polyimines were characterized using FTIR, XRD, H1NMR, TGA, and DSC. The optical characteristics of polyimine derivatives were investigated using a UV–Vis spectrophotometer. The absorption spectra showed a main absorption band around 372 nm for polyimine (P1) and 381 nm for polyimine (P2). The optical energy was calculated and found to be 2.49 and 2.68 eV. The photoluminescence of the polyimine derivatives was measured and analyzed by spectrofluorometer and Laser photoluminescence experiment and the emission color was studied using CIE graphs. The fluorescence spectra showed an emission peak at 548 nm for polyimine (P1) with yellow green color in CIE graph, while for polyimine (P2) the emission band was located at 440.5 nm with blue color in CIE graph. Photoluminescence quantum yield PLQY was measured for the polyimine P1 and P2 in both liquid and Solid states and indicated the AIE behavior of the polyimines. TD-DFT simulations were applied to the polyimine derivatives where the structures were geometrically optimized and the spectroscopic characterizations were evaluated.

Abstract Green nanotechnology has recently been recognized as a more proper and safer tool for medical applications thanks to its natural reductions with low toxicity and avoidance of injurious chemicals. The macroalgal biomass was used for nanocellulose biosynthesis. Algae are abundant in the environment and have a high content of cellulose. In our study, we extracted parent cellulose from Ulva lactuca where consecutive treatments extracted cellulose to obtain an insoluble fraction rich in cellulose. The extracted cellulose has the same results obtained by matching it with reference cellulose, especially the same Fourier transform infrared (FTIR) and X-Ray diffraction (XRD) analysis peaks. Nanocellulose was synthesized from extracted cellulose with hydrolysis by sulfuric acid. Nanocellulose was examined by Scanning electron microscope (SEM) shown by a slab-like region as Fig. 4a and Energy dispersive X-ray (EDX) to examine the chemical composition. The size of nanocellulose in the range of 50 nm is calculated by XRD analysis. Antibacterial examination of nanocellulose was tested against Gram+ bacteria like Staphylococcus aureus (ATCC6538), Klebsiella pneumonia (ST627), and Gram-negative bacteria such as Escherichia coli (ATCC25922), and coagulase-negative Staphylococci (CoNS) to give 4.06, 4.66, 4.93 and 4.43 cm as respectively. Comparing the antibacterial effect of nanocellulose with some antibiotics and estimating minimal Inhibitory Concentration (MIC) of nanocellulose. We tested the influence of cellulose and nanocellulose on some fungi such as Aspergillus flavus, Candida albicans, and Candida tropicalis. These results demonstrate that nanocellulose could be developed as an excellent solution to these challenges, making nanocellulose extracted from natural algae a very important medical material that is compatible with sustainable development.

Abstract The present study fabricated regenerated cellulose nanofiber incorporated with activated carbon and functionalized rC/AC3.7 with EDTA reagent for methylene blue (MB) dye removal. The rC/AC3.7 was fabricated by electrospinning cellulose acetate (CA) with activated carbon (AC) solution followed by deacetylation. FT-IR spectroscopy was applied to prove the chemical structures. In contrast, BET, SEM, TGA and DSC analyses were applied to study the fiber diameter and structure morphology, the thermal properties and the surface properties of rC/AC3.7-EDTA. The CA was successfully deacetylated to give regenerated cellulose nanofiber/activated carbon, and then ethylenediaminetetraacetic acid dianhydride was used to functionalize the fabricated nanofiber composite. The rC/AC3.7-EDTA, rC/AC5.5-EDTA and rC/AC6.7-EDTA were tested for adsorption of MB dye with maximum removal percentages reaching 97.48, 90.44 and 94.17%, respectively. The best circumstances for batch absorption experiments of MB dye on rC/AC3.7-EDTA were pH 7, an adsorbent dose of 2 g/L, and a starting MB dye concentration of 20 mg/L for 180 min of contact time, with a maximum removal percentage of 99.14%. The best-fit isotherm models are Temkin and Hasely. The outcome of isotherm models illustrates the applicability of the Langmuir isotherm model (LIM). The maximal monolayer capacity Q m determined from the linear LIM is 60.61 for 0.5 g/L of rC/AC3.7-EDTA. However, based on the results from error function studies, the generalized isotherm model has the lowest accuracy. The data obtained by the kinetic models’ studies exposed that the absorption system follows the pseudo-second-order kinetic model (PSOM) throughout the absorption period.

ABSTRACTDental caries is an infectious disease that is a major concern for dentists. Streptococci and Lactobacilli were long thought to be the primary etiology responsible for caries. Candida albicans with acidogenic and aciduric characteristics has recently been implicated in the onset and progression of cariogenic lesions. Moreover, due to the increased resistance to common antimicrobials, the discovery of innovative candidates is in high demand. Therefore, our study might be the first report that explores the efficacy of glass ionomer cement (GIC) incorporated with a newly modified carboxylated chitosan derivative (CS-MC) against multidrug-resistant (MDR) and/or pandrug resistant (PDR) C. albicans isolated from the oral cavity. In this work, four CS-MC-GIC groups with different concentrations were formulated. Group four (CS-MC-GIC-4) gave a significant performance as an anticandidal agent against selected PDR Candida strain, with an obvious decrease in its cell viability and high antibiofilm activity. It also, enhanced all the mechanical properties and supports cell viability of Vero cells as a nontoxic compound. Moreover, CS-MC-GIC-4 inhibited neuraminidases completely, which might provide a novel mechanism to prevent dental/oral infections. Thus, findings in this study open up new prospect of the utilization of CS-MC-GIC as a novel dental filling material against oral drug-resistant Candida. [Figure: see text]

In the contemporary, digitally–driven era, the prevalence of electronic devices has drastically escalated electromagnetic (EM) pollution levels, marking a significant environmental challenge. Electrospun fiber composites of polyvinylidene fluoride (PVDF) and Barium hexaferrite (BHF) were analyzed for their potential usage in X-band electromagnetic shielding applications (EMSAs). Pure PVDF and BHF-PVDF fiber composite were manufactured by needleless electrospinning. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and EM measurements utilizing a vector network analyzer (VNA) are all used to describe the prepared samples. The XRD and FTIR analyses confirmed the successful incorporation of BHF into the PVDF matrix. The results show that adding PVDF to BHF in fiber form enhances the reflection loss (RL), indicating improved electromagnetic shielding effectiveness (EMSE). The SEM analysis revealed that the fiber composite had a uniform fiber diameter distribution. In contrast, the TGA analysis demonstrated good thermal stability of the fiber composite. Polymer samples were evaluated to enhance gamma radiation and neutron particle attenuation. MCNP5 and Phy-X/PSD software were used to study semi-crystalline fluorocarbon polymer (PVDF) and barium hex ferrite BaFe12O19 (30 wt%) with PVDF (70 wt%). The MCNP5 programme simulated 0.015–15 MeV radiation attenuation. Additionally, the Phy-X/PSD programme verified the simulated µ values for the chosen Mxenes materials. The MCNP-5 code and Phy-X/PSD results were agreed. The linear attenuation coefficients for the polymer samples ranged from 3.166 to 0.032 cm2.g−1 for PVDF and from 73.960 to 0.113 cm2.g−1 for PVDF and BHF-PVDF Fiber at photon energies from 0.015 to 15 MeV. Overall, the electrospun fiber composite of PVDF and BHF particles shows promise for EMSAs in the X-band range. The enhanced RL observed in our study suggests that these fiber composites could be used to protect against electromagnetic radiation (EMR) from electronic devices, which is increasingly concerning in today's modern society.

Scarcity of water is a substantial impediment to the growth and yield of crop species. In this study, free-radical copolymerization was used to tailor novel formulations of superabsorbent nanocomposites (SANCs). The prepared SANCs were characterized using FT-IR spectra, SEM micrograph, TGA and X-Ray diffraction. Following SANC preparation, the swelling behavior was examined. Also, SANC's soil burial degradation and water retention were investigated. A pot trial was performed to examine the growth performance and physio-biochemical traits of Faba bean in the presence and absence of SANC under water-stress (40% FC). Water stress decreased chlorophyl and sugars contents, CAT, APX, SOD, and PPO activities. Nonetheless, water stress raised POD and GR activities, and AsA, DPPH, PMA, H2O2, MDA, and soluble proteins levels. SANC alleviated water stress by boosting Faba bean growth and physiological characteristics. SANC enhanced Chl b, carotenoids, Fv/Fm, CAT, GR and SOD, contributing to better growth of stressed Faba bean.

This work adopted a strategy to use new functional high-performance piezoelectric materials for sustainable energy production in wearable self-powered electrical devices. An innovative modification in electrospinning was used to produce highly aligned nanofibers. In the nanogenerator, the flexible membrane constituents were tunefully combined. The novel composite nanofibers were made of Poly (vinylidene fluoride) PVDF, loaded with ZnO@ZnS core–shell nanoparticles to achieve a non-brittle performance of the hetero nanoparticles and piezoelectric polymer. A nanofiber mat was inserted between two thermoplastic sheets with conductive electrodes for application in wearable electronic devices. Complete spectroscopic analyses were performed to characterize the nanofiber’s material composition. It is shown that the addition of 10 wt % ZnO@ZnS core–shell nanoparticles significantly improved the piezoelectric properties of the nanofibers and simultaneously kept them flexible due to the exceedingly resilient nature of the composite. The superior performance of the piezoelectric parameter of the nanofibrous mats was due to the crystallinity (polar β phase) and surface topography of the mat. The conversion sensitivity of the PVDF device recorded almost 0.091 V/N·mm3, while that of the PVDF—10 wt % ZnO@ZnS composite mat recorded a sensitivity of 0.153 V/N·mm3, which is higher than many flexible nano-generators. These nanogenerators provide a simple, efficient, and cost-effective solution to microelectronic wearable devices.

The design of biomaterials for wound and mucosal healing is pivotal to keep a high level of health care. Scaffolds of polycaprolactone (PCL) encapsulated with hydroxyapatite that has been modified via different contributions of thallium (Tl) ions having the formula of [Tl2xCa10-x(PO4)6-x(OH)2] have been fabricated. The obtained results showed that the maximum height of the roughness (Rt) of the fabricated Tl-HAP@PCL nanofiber has increased from 612 to 819 nm, depending on the content of Tl+ ions. Moreover, the contact angle exhibited a significant decrease from 97.21° at 0.0Tl-HAP@PCL to 29.01° for 1.0Tl-HAP@PCL. Importantly, mechanical properties measurements' showed that the maximum strain at the break has deteriorated from 131.7 ± 4.3 to 129.31 ± 4.6% for the lowest and the highest Tl contribution. The scaffolds’ performance in a wound and mucosal treatments might be triggered upon the development of cell viability. In view of these findings, the fabricated Tl-HAP@PCL composites have evidently an efficient wound dressing capability and cell viability that make these nanofibers promising candidates for other related medical/clinical applications.

Controlled-release technology was introduced to offer an incredible guarantee for improving the adequacy of the existing active molecules and solving the related environmental troubles. Our study attempts to utilize the controlled release of alginate niclosamide-l-glutamate formulation to control Schistosoma mansoni intermediate host (Biomphalaria alexandrina snail) and to evaluate the amount of niclosamide released in relation to its attraction and mortality rate. Results: polymeric formulations B3-4b at a concentration of 0.3 ppm niclosamide in combination with 75% l-glutamate caused 100% mortality of B. alexandrina snails 5-day post-exposure. Stable snails mortality rates were obtained post-exposure to polymer B3-4a (R2 = 0.9823). The high potential of the polymeric formulations B3-4a (0.2 ppm niclosamide and 75% l-glutamate) to attract snail toward polymer direction was manifested by 80%, 14%, 6% and 0% snail in areas (I), (II), (III) and (IV), respectively 24-hr post-exposure. While, B3-4a showed a high mortality rate of attracted snails resembled by 40% and 100% on the 2nd and 7th days, respectively. The modified structure of polymer-niclosamide-l-glutamate prolonged the validity and efficiency of the niclosamide. Slowly released molluscicide was effective at lower concentrations with increasing concentrations of the applied attractant that could reduce its toxicity to the water ecosystem. Keywords: Biomphalaria alexandrina, Control of schistosomiasis, Controlled release molluscicides, l-glutamate attractant, Niclosamide

A range of heterogeneous, inexpensive and benign Schiff bases-montmorillonite composites were synthesized and screened for their antibacterial activity against common microbial pathogens. Sodium montmorillonite (Na-MMT) clay was modified with tris(2-ethylamine) in the presence of dilute HCl to yield a quaternary salt of tris(2-ethylamine) modified clay. The Schiff bases were then fabricated from the reaction of the modified montmorillonite using different aldehydes. The structures of the obtained compounds were confirmed by Fourier transformer Infrared (FT-IR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). All the obtained composite materials were screened for their antibacterial activities against the multi-drug resistant (MDR) strains. It was reasoned that the modified MMT-based composites has the ability to absorb the different micro-organisms onto the surface, and accordingly act as an effective antibacterial agent. All the composites showed significant antibacterial activity between 2.5 and 20 mg/mL against the MDR bacterial strains. The benzyl-based/modified MMT and the tertiary amino-based/modified MMT was found to be the most effective antibacterial agent. Keywords: Organoclay, Antibacterial composite, Montmorillonite, Tris(2-ethylamine)

For the detection of Cd(II) in aquatic media, a novel dicyanomethylene dihydrofuran hydrazone(DCDHFH)-based colorimetric chemosensor was developed. DCDHFH was prepared by an azo-coupling process involving the diazonium chloride of 2, 4-dichloroaniline and a dicyanomethylene dihydrofuran heterocyclic moiety bearing an active methyl group. The DCDHFH chromophore showed strong solvatochromism depending on solvent polarity due to electronic delocalization. The pH sensory effects of the DCDHFH chromophore were also explored. DCDHFH could be used to identify Cd(II) in the presence of other competitive metals, as indicated by variations in color and absorbance spectra. In the presence of cadmium ions, the synthesized DCDHFH probe with hydrazone recognition moiety exhibited a significant sensitivity and selectivity to cadmium ions at the ppm concentration level (10–250 ppm). A DCDHFH-immobilized paper test strip was also prepared and effectively used for the detection of cadmium in aqueous media at various concentrations. According to CIE Lab’s criteria, colorimetric strength (K/S), and the UV–Vis absorbance spectra, the cadmium detection abilities of the DCDHFH-immobilized paper strips were evaluated. The optimal pH range for the determination of Cd(II) was monitored in the area of 5.5–6.3, with a fast chromogenic change from yellow to red relying on the Cd(II) concentration. The deposition of dicyanomethylene dihydrofuran hydrazone onto the paper strip’s surface was studied by scanning electron microscopy (SEM).

Low-cost composites with high water absorption capacity were prepared by free radical copolymerization of acrylic acid (AA), acrylamide (AM) and gelatin in aqueous media using N,N' methylene bis-acrylamide (MBA) as crosslinker, potassium persulfate (KPS) as initiator and rice husk (RH) as a filler. The composites were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of different parameters such as the alkaline treatment on the rice husk, the media pH and salinity and the composition of the composites on their water absorption capacity were investigated. The water retention and biodegradation tests in soil were also carried out. The optimized composite containing treated RH showed a maximum water uptake value of 825 g∙g−1 in distilled water and good resistance in saline solutions and in the pH range of 6–10. Positive effects on the soil water retention were obtained after 30 days samples of soil containing 1 wt% of superabsorbent composites still contained about 7% of the initial absorbed water. Growth attributes, photosynthetic pigments and nodulation traits of droughted peanut were improved by 60 kg∙ha−1 dosage of SAC. On the basis of the good results of water retention and controlled biodegradability in the soil, the developed composites have the potential to be used in agriculture for better water management, with relevant environmental benefits.

Sodium alginate-g-poly(acrylic acid-co-2-hydroxyethyl methacrylate)/montmorillonite superabsorbent composites (SACs) were prepared by graft copolymerization of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto sodium alginate (Na-Alg) in the presence of montmorillonite (MMT) using N,N′-methylenebisacrylamide (MBA) as a crosslinker and potassium persulfate (KPS) as an initiator in aqueous solution. The composite structures were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscope (SEM). The effect of % initiator, crosslinker amount and clay ratio on the swelling capacity was investigated. The results indicated that the highest swelling capacity of the composites in distilled water was 752 g/g by using 1.25% KPS and 0.06% MBA, 75% AA, 6.25% HEMA and 12.5% Na-Alg. Different samples were loaded with urea to evaluate their release potentials, and the release was studied by measuring the conductivity. The amount of urea release increased with increasing MMT amount. Keywords: Superabsorbent, Sodium alginate, Swelling, Composites, Montmorillonite, Slow-release, Agrochemical

New antibacterial composites were synthesized by modification and functionalization of montmorillonite (MMT). The antibacterial composites were synthesized by the reaction of MMT clay with the quaternary salt of p-N,N-dimethylamino benzaldehyde which produced modified functionalized montmorillonite composite in the form of Schiff bases. The Schiff bases (4–11) were obtained by the reaction of functionalized montmorillonite with various amines namely o-anisidine, anthranilic acid, p-carboxy aniline, p-methyl aniline, p-methoxy aniline, p-hydroxy aniline, p-nitro aniline and p-phenylene diamine. The structures of the newly prepared composites were elucidated by Fourier transform infra red (FT-IR), thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). The antibacterial activities of these composites were investigated by the ‘cut plug’ method against Gram-negative bacteria such as Escherichia coli, Serratia marcescens, Enterobacter cloacae, Shigella dysenteriae, Salmonella enterica and Proteus vulgaris, and Gram-positive such as Bacillus subtilis and Staphylococcus aureus which showed high antimicrobial activities at relatively low concentrations (2.5–20 mg/mL). These promising results pave the way in the future to use the newly synthesized composites as antibacterial agents for water treatment against pathogenic bacteria which exist in polluted water courses. Keywords: Antimicrobial activities, Montmorillonite, p-N,N-dimethylamino benzaldehyde, Water treatment, Schiff bases

The effective degradation of hazardous contaminants remains an intractable challenge in wastewater processing, especially for the high concentration of salty azo dye wastewater. However, some unique yeast symbionts identified from the termite gut system present an impressive function to deconstruct some aromatic compounds, which imply that they may be valued to work on the dye degradation for various textile effluents. In this investigation, a newly isolated and unique yeast strain, Sterigmatomyces halophilus SSA-1575, was identified from the gut system of a wood-feeding termite (WFT), Reticulitermes chinensis. Under the optimized ambient conditions, the yeast strain SSA-1575 showed a complete decolorization efficiency on Reactive Black 5 (RB5) within 24 h, where this azo dye solution had a concentration of a 50 mg/L RB5. NADH-dichlorophenol indophenol (NADH-DCIP) reductase and lignin peroxidase (LiP) were determined as the key reductase and oxidase of S. halophilus SSA-1575. Enhanced decolorization was recorded when the medium was supplemented with carbon and energy sources, including glucose, ammonium sulfate, and yeast extract. To understand a possible degradation pathway well, UV-Vis spectroscopy, FTIR and Mass Spectrometry analyses were employed to analyze the possible decolorization pathway by SSA-1575. Determination of relatively high NADH-DCIP reductase suggested that the asymmetric cleavage of RB5 azo bond was mainly catalyzed by NADH-DCIP reductase, and finally resulting in the formation of colorless aromatic amines devoid of any chromophores. The ecotoxicology assessment of RB5 after a decolorization processing by SSA-1575, was finally conducted to evaluate the safety of its metabolic intermediates from RB5. The results of Microtox assay indicate a capability of S. halophilus SSA-1575, in the detoxification of the toxic RB5 pollutant. This study revealed the effectiveness of halotolerant yeasts in the eco-friendly remediation of hazardous pollutants and dye wastewater processing for the textile industry.

On March 11, 2020, the novel Corona virus disease (COVID-19), was described as a pandemic by World Health Organization (WHO). Globally, the COVID-19 has not only affected the public health socially but also has rigorously affected economically. Substantial declines in income, increase in unemployment, and distractions in the transportation, amenities, and industrial sectors are amongst the major concerns of the pandemic disease extenuation. Furthermore, the governments of most of the countries underestimated the menaces of COVID-19 spread and were typically responsive for the calamities in their respective countries. As outbreak of this pandemic is not likely to wane in the nearby future, preventive actions are prerequisite to prevent infection spread, save people lives and also to save the economic affluence. In this review, based on the present knowledge and available literature, we have demonstrated the various aspects of pre-and post-COVID-19 effects over the social and economic phases worldwide. Moreover, the evidence based data have been summarized regarding threats, social influences, scientific upgrades, moral dynamics, stress and adapting in the pre- and post- COVID-19 situations.

The process of secondary intention wound healing includes long repair and healing time. Electrospun nanofibrous scaffolds have shown potential for wound dressing. Biopolymers have gained much attention due to their remarkable characteristics such as biodegradability, biocompatibility, non-immunogenicity and nontoxicity. This study anticipated to develop a new composite metronidazole (MTZ) immobilized nanofibrous scaffold based on poly (3-hydroxy butyrate) (PHB) and Gelatin (Gel) to be utilized as a novel secondary intention wound healing accelerator. Herein, PHB and Gel were mixed together at different weight ratios to prepare polymer solutions with final concentration of (7%), loaded with two different concentrations 5% (Z1) and 10% (Z2) of MTZ. Nanofibrous scaffolds were obtained by manipulating electrospinning technique. The properties of MTZ immobilized PHB/Gel nanofibrous scaffold were evaluated (SEM, FTIR, TGA, water uptake, contact angle, porosity, mechanical properties and antibacterial activity). Additionally, in vitro cytocompatibility of the obtained nanofibrous scaffolds were assessed by using the cell counting kit-8 (CCK-8 assay). Moreover, in vivo wound healing experiments revealed that the prepared nanofibrous scaffold highly augmented the transforming growth factor (TGF-β) signaling pathway, moderately suppressed the pro-inflammatory cytokine (IL-6). These results indicate that MTZ immobilized PHB/Gel nanofibrous scaffold significantly boost accelerating secondary intention wound healing.

Alginates are regarded as high-value biomacromolecules. A pursuit for new bacterial species that can produce novel alginates for various applications in different industries including the pharmaceutical and food industries as well as the field of medicine is still needed. Variations in the molecular weight and sugar composition of alginates depend on the culture medium composition and different physical conditions provided during fermentation. The aim of this study was to obtain a maximum alginate production by the potent Egyptian bacterial strain Azotobacter vinelandii , out of the 30 tested Azotobacter isolates. The composition of the production medium and environmental growth conditions during fermentation were optimized to ensure consistency and to enhance alginate production. Nine variables were optimized using the Plackett-Burman randomization method. Eighteen trials were performed to verify the variables to obtain high alginate production levels. Temperature as well as sucrose and NaCl concentrations have been found to affect the alginate production by A. vinelandii significantly and were therefore chosen for further improvement of the medium using the Box-Behnken design. The Box-Behnken model was optimized mathematically using the Excel solver. The results were analyzed statistically by ANOVA multiple regression analysis and different statistical methods (coefficient, standard error, t statistic, and confidence interval). On using the Plackett-Burman and Box-Behnken designs, the biggest alginate production rates were found to be 3.8 and 4.94 g/l/day, respectively. Addition of 00.1 g/l MgSO4, 0.01 g/l FSO4, and 0.001 g/l NaMoO4 to the culture medium further enhanced the alginate production and yielded 5.4 g/l/day and 8.5 g/l/day. Thus, the obtained alginate was purified using Sephadex G-100 Gel chromatography and compared with a standard by IR correlation. The alginate was found to be composed of 50–70% carbohydrates and 60–80% uronic acid. The techniques used in this survey were found useful for improving the production of alginates.

In the current study, α-aminophosphonates containing thiadiazole moiety (1–4) was synthesized, characterized and their antioxidant and anticancer activities were carried out. The compounds (1–4) were synthesized from the reaction of 2-amino-5-methyl-1,3,4-thiadiazole with various aldehydes, triphenylphosphite and mixed valence Cu(I)/Cu(II) inorganic coordination polymer as a catalyst. The elucidation of compounds structures were carried out using different spectroscopic techniques. The antioxidant properties were carried out using radical scavenging methods (DPPH) which exhibited excellent scavenging activity particularly with compound 3. The cytotoxic effects of the five compounds on the human hepato cellular carcinoma (HepG2) and breast adeno carcinoma (MCF7) cell lines were evaluated using MTT assay which revealed the presence of cytotoxic effect with highest activity for compound 3 on HepG2 and compound 1 on MCF7. This suggests that these five compounds, particularly compounds 1 and 3, have antioxidant and anticancer effect and could be used as novel chemotherapeutic compounds but this needs further in vivo investigation to confirm our in vitro results.

Poly(vinyl alcohol), PVA is a polymer of great importance because of its many appealing characteristics specifically for various pharmaceutical and biomedical applications. Physically crosslinked hydrogel membranes composed of different amounts of hydroxyethyl starch (HES) in (PVA) and ampicillin were prepared by applying freeze–thawing method. This freezing–thawing cycle was repeated for three consecutive cycles. Physicochemical properties of PVA–HES membrane gel such as gel fraction, swelling, morphology, elongation, tensile strength, and protein adsorption were investigated. Introducing HES into freeze–thawed PVA structure affected crystal size distribution of PVA; and hence physicochemical properties and morphological structure have been affected. Increased HES concentration decreased the gel fraction %, maximum strength and break elongation. Indeed it resulted into a significant incrementing of the swelling ability, amount of protein adsorption, broader pore size, and pore distribution of membrane morphological structure. Furthermore, an increase in HES concentration resulted in better and still lower thermal stability compared to virgin PVA and freeze–thawed PVA. The maximum weight loss of PVA–HES hydrogel membranes ranged between 18% and 60% according to HES content, after two days of degradation in phosphate buffer saline (PBS), which indicates they are biodegradable. Thus, PVA–HES hydrogel membranes containing ampicillin could be a novel approach for biomedical application e.g. wound dressing purposes.

Functionalized polymers and their polymer nature give them more advantages than the corresponding small molecules. In this respect, polymeric ammonium and phosphonium salts were prepared by chemical modifications of poly(vinyl alcohol) (PVA) aiming to explore their antimicrobial activities against pathogenic bacteria and fungi. The modifications were performed by chloroacetylation with chloroacetyl chloride. Incorporation of the ammonium and phosphonium salts was conducted by the reaction of chloroacetylated poly(vinyl alcohol) (CPVA) with triethylamine (TEA), triphenylphosphine (TPP), and tributylphosphine (TBP). The antimicrobial activity of the polymers against variety of test microorganisms was examined by the cut plug and viable cell counting methods of shake cultures of 10 times dilute nutrient broth and Sabouraud’s media, seeded with the test microorganisms. It was found that the immobilized polymers exhibited antimicrobial activity against the Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Shigella sp. and Salmonella typhi) and Gram positive bacteria (Bacillus subtilis and B. cereus) and the dermatophyte fungus (Trichophyton rubrum). The growth inhibition of the test microorganisms (ratio of surviving cell number, M/C) varied according to the composition of the active group in the polymer and the test organism. It increased by increasing the concentration of the polymer. Triphenyl phosphonium salt of the modified poly(vinyl alcohol) exhibited the most biocidal activity against both Gram-negative and Gram-positive bacteria after 24 h.

An investigation into the potential ruthenium(II) 1-3 complexes of type [RuCl2(P)2(N)2] using triphenylphosphine and 1,3-bis-diphenylphosphinepropane and 3-(triethoxysilyl)propylamine has been carried out at room temperature in dichloromethane under an inert atmosphere. The structural behaviors of the phosphine ligands in the desired complexes during synthesis were monitored by 31P{1H}-NMR. The structure of complexes 1-3 described herein has been deduced from elemental analyses, infrared, FAB-MS and 1H-, 13C- and 31P-NMR spectroscopy. Xerogels X1-X3 were synthesized by simple sol-gel process of complexes 1-3 using tetraethoxysilane as co-condensation agent in methanol/THF/water solution. Due to their lack of solubility, the structures of X1-X3 were determined by solid state 13C-, 29Si- and 31P-NMR spectroscopy, infrared spectroscopy and EXAFS.

Segmented polyurethanes containing azo aromatic groups in the main chain were synthesized by reaction of 3,3'-azobis(6-hydroxybenzoic acid) (ABHB), 5-[4-(hydroxyphenyl)azo] salicylic acid (HPAS), and 5-[1-hydroxynaphthyl)azo] salicylic acid (HNAS) with hexamethylenediisocyanate (HDI). All synthesized monomers and polymers were characterized by elemental analysis, FTIR, 1H-NMR spectra, TGA and DSC analysis. All the synthesized azo polymers showed good thermal stability and the onset decomposition temperature of all these polymers was found to be above 195 ºC under nitrogen atmosphere.The release of 5-ASA under physiological conditions (pH = 7.8 and pH = 1.5) was investigated at body temperature (37 ºC). The release rate of 5-ASA increased with increasing pH (i.e., 7.8 > 1.5).

Novel Ru(II) complex-based hybrid inorganic-organic materials immobilized via a diamine co-ligand site instead of the conventional diphosphine ligand have been prepared. The complexes were prepared by two different methods: sol-gel and surface modification techniques. The structures of the desired materials were deduced by several available physical measurements like elemental analyses, infrared, FAB-MS and 1H-, 13C- and 31P-NMR spectroscopy. Due to a lack of solubility the structures of xerogel 3 and modified 4 were studied by solid state 13C-, 29Si- and 31P-NMR spectroscopy, infrared spectroscopy and EXAFS. These materials were stable enough to serve as hydrogenation catalysts. Selective hydrogenation of functionalized carbonyls in a,b-unsaturated compounds was successfully carried out under mild conditions in a basic medium using these complexes as catalysts.