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Nano-sized metal oxalate precursors was thermally treated and investigated to produce high temperature superconducting ceramics with a formula of HoBa2Cu307-δ. The nano metal oxalate powders were subjected to different heat treatments at various temperatures for the phase formation study. The high-Tc phase was observed for all samples as an evidence for the single step transition of (R-T) curves. The Tc(ij=o) f°r Ho 123 is 91 K and 90 K for samples sintered at 920°C, 930°C and 88 K for samples sintered at 940° C and 950° C, respectively. XRD data showed single phase of an or-thorhombic structure where a small amount of none superconducting phase Ho2BaCuOs (Ho211) phase was detected. The Ho211 phase was increased as sintering temperature increased due to the decomposition process and affected the transport properties. SEM micrographs showed large grain sizes that are randomly distributed. However, the grain size decreased as the sintering temperature increased which resulted in the formation of weak-links and hence decreases the transport properties. Using nano-sized metal oxalate precursors simplified the formation of HTSC materials with less processing temperatures which could be beneficial in superconducting tape industry. In addition, control of the sintering temperature lead to the formation of Hol23 phase with optimum amount of Ho211 phase which acts as pinning centers and improves the transport properties. [ABSTRACT FROM AUTHOR]

The formation of GdBa2Cu3O7-δ(Gd123) from metal oxalate precursor with average grain size less than 40 nm using the coprecipitation method is reported. The coprecipitated powders were heated at 900°C for 12 hours, pelletized and then sintered at 920°C for 15, 20 and 25 hours, respectively. All samples showed a dominant Gd123 phase with the orthorhombic structure. The amount of impurity phase Gd2BaCuO5(Gd211) can be controlled by varying the sintering time. This work shows that nano-sized oxalate powders produced via coprecipitation method can be an effective technique to synthesize high quality GdBa2Cu3O7-δ samples where the amount of (Gd211) can be controlled by varying the sintering duration. The percentage of Gd211 impurity decreased with increase in sintering time. This result is useful in utilizing the Gd211 phase as pinning center in enhancing the transport properties. [ABSTRACT FROM AUTHOR]

The magnetotransport and magnetoresistive (MR) properties of manganese-based La0.67Ca0.33MnO3 perovskite with different grain sizes are reported. The electrical resistivity was measured as a function of temperature in magnetic fields of 0.5 and 1 T. The insulator–metal transition temperature, TIM, shifted to a higher temperature with the application of the magnetic field. In zero field, TIM is almost constant (∼271 K) for all samples except for the sample with the largest grain size, where TIM=265 K. The temperature dependence of resistivity was fitted with several equations in the metallic (ferromagnetic) region and the insulating (paramagnetic) region. The density of states at the Fermi level, N( EF), and the activation energy of electron hopping were estimated by fitting the resistivity versus temperature curves. The ρ– T2 curves are nearly linear in the metallic regime, but the ρ– T2.5 curves exhibit a deviation from linearity. The variable range hopping model and small polaron hopping model fit the data well in the high-temperature region, indicating the existence of the Jahn–Teller distortion that localizes the charge carriers. MR was found to increase with an increase in the magnetic field, an effect which is attributed to the intergrain spin tunneling effect. [ABSTRACT FROM AUTHOR]

The Bi(Pb)-2223 superconductor has been prepared via coprecipitation (COP) method from solutions of metal acetates and 2-propanol solution of oxalic acid at low temperature (0–2 °C). The metal oxalates powder was subjected to precalcination of 12 h at 730 °C, followed by 24 h calcination at 845 °C. The pelletized powder was sintered for 24, 48 and 100 h at 850 °C. The dominance of high- T C phase was observed for all samples as evidenced in the single step transition of (R–T) curves. The T C(R = 0) for samples sintered at 24, 48 and 100 h were 102, 102 and 104 K, respectively. XRD data showed the tetragonal structure for all samples followed by the enhancement of the 2223 phase as sintering time increased. Ac magnetic susceptibility measurements showed the improvement of the grain connectivity as sintering time increased. SEM micrographs showed large flaky grains of ∼7 μm in size and randomly distributed, which belong to 2223 phase. The degree of grains alignment increased as the sintering time increased. [ABSTRACT FROM AUTHOR]

Aims: We develop and evaluate copper-based metal-organic frameworks (Cu-MOFs) incorporating cromolyn as a linker to enhance structural stability, drug delivery efficiency, and therapeutic potential, particularly for breast cancer treatment., Materials & Methods: Two Cu-MOF formulations were synthesized: Cu-MOFs-BDC-DOX (using terephthalic acid) and Cu-MOFs-CROMO-DOX (using cromolyn as a linker). Characterization was performed using SEM/TEM for morphology, and FTIR, XRD, and TGA to confirm structural integrity. Drug encapsulation efficiency and release profiles were assessed, followed by in vitro cytotoxicity, cell migration, and colony formation assays using MDA-MB-231 breast cancer cells., Results: Both formulations demonstrated a high encapsulation efficiency (83-91%) and sustained drug release over 48 h at pH 7.4. Cu-MOFs-CROMO-DOX exhibited superior cytotoxicity with an IC50 of 0.88 ± 0.07 µM compared to 7.1 ± 0.11 µM for Cu-MOFs-BDC-DOX. Both formulations inhibit cancer cell migration and colony formation in a dose-dependent manner., Conclusions: The Cu-MOFs-CROMO-DOX formulation demonstrated enhanced therapeutic potential, outperforming its counterpart in targeting breast cancer cells. This study highlights the promise of MOF-based nanocarriers in overcoming the limitations of conventional chemotherapy, offering a pathway to more effective and targeted cancer treatments with reduced side effects.

Anthocyanins (ANCs) are water-soluble pigments with antioxidant properties, offering potential as alternatives to synthetic food colorants. However, their stability is compromised by factors such as pH, temperature, and light exposure. Previous research demonstrated improved pH stability in black grape ANCs through cobalt ion (Co +2 ) complexation. This study investigates the effects of Co +2 complexation on the thermal and light stability of black grape ANCs extracted from pomace. These ANCs were purified, complexed with Co +2 (ANC-Co +2 ), and diluted in a pH 4.5 buffer solution. Purified ANCs were also diluted in a pH 3.5 buffer solution. Both ANCs and ANC-Co +2 were heated to 40°C, 60°C, and 80°C for 7 h to assess thermal stability. To evaluate light stability, ANCs and ANC-Co +2 were stored separately under ultraviolet (UV) light and daylight for one week. Thermal stability results revealed that complexation could significantly ( P ≤0.05) extend ANC half-life by more than threefold and reduce temperature sensitivity by approximately 50%. Thermal degradation of ANCs was endothermic, nonspontaneous, and more structured in the transition state, as indicated by thermodynamic parameters (activation enthalpy (ΔH)>0, free energy of inactivation (ΔG)>0, and activation entropy (ΔS)<0). Light stability tests revealed that complexation significantly ( P ≤0.05) extended ANC half-life by over tenfold and twentyfold under UV and daylight exposure, respectively. Therefore, Co +2 complexation represents an effective technique to enhance the thermal and light stability of grape ANCs, making them more suitable for use as food colorants., Competing Interests: AUTHOR DISCLOSURE STATEMENT The authors declare no conflict of interest., (© 2024 The Korean Society of Food Science and Nutrition.)

Anthocyanins (ANCs) are water-soluble pigments that are useful as nutraceuticals due to their health benefits. This study was performed to evaluate the storage stability of purified and crude red grape ANCs in Raha Sweet (RS) during storage and to evaluate its sensory properties. ANCs were extracted from red grape pomace and purified with a macroporous resin. RS was prepared and colored with a synthetic food dye, Carmoisine (control), and ANCs (crude and purified). Pigments were extracted from RS weekly for a period of seven weeks and the absorbance was read spectrophotometrically. RS colored with ANCs was evaluated for its color and other sensory properties against another RS colored with the control. Results showed that the degradation of ANCs in RS followed the first-order reaction model, unlike the control, which showed no degradation during storage. The half-life of crude ANCs was three times higher than that of the purified ones, and RS colored with ANCs received a significantly ( p < 0.05) lower score for color than that of RS colored with the control. ANCs could provide the food industry with a natural alternative to synthetic dyes to color foods with high sugar content that are stored for a short period of time.

This study focused on synthesizing a cellulose-based hydrogel nanocomposite as a green hydrogel by adding a microcrystalline cellulose (MC) solution to carboxymethyl cellulose sodium (CMC-Na) with citric acid as a cross-linker. Y 2 O 3 nanoparticles were incorporated during hydrogel preparation in different ratios (0.00% (0 mmol), 0.03% (0.017 mmol), 0.07% (0.04 mmol) and 0.10% (0.44 mmol)). FTIR analysis confirmed the cross-linking reaction, while XRD analysis revealed the hydrogels' amorphous nature and identified sodium citrate crystals formed from the reaction between citric acid and CMC-Na. The swelling test in deionized water (pH 6.5) at 25 °C showed a maximum swelling percentage of 150% after 24 h in the highest nanoparticle ratio. The resulting cellulose hydrogels were flexible and exhibited significant antibacterial activity against Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ). The synthesized cellulose-based hydrogel nanocomposites are eco-friendly and suitable for medical applications.

The aim of this research is to study the anticorrosive behavior of a coating consisting of modified montmorillonite nanoclay as an inorganic green inhibitor. The anticorrosion protection for mild steel in 1.0 M HCl solution is studied via weight loss, electrochemical methods, SEM, and XRD. The results proved that montmorillonite nanoclay acts as a good inhibitor with a mixed-type character for steel in an acidic solution. Both anodic and cathodic processes on the metal surface are slowed down. There is a clear direct correlation between the added amount of montmorillonite nanoclay and the inhibition efficiency, reaching a value of 75%. The inhibition mechanism involves the adsorption of the montmorillonite nanoclay onto the metal surface. Weight loss experiments are carried out with steel samples in 1.0 M HCl solution at room temperature, and the same trend of inhibition is produced. SEM was used to image the surface at the different stages of the corrosion inhibition process, and also to examine the starting nanoclay and steel. XRD was used to characterize the nanoparticle structure of the coating. Montmorillonite nanoclay is an environmentally friendly material that improved the corrosion resistance of mild steel in an acidic medium.

In this research, some physical properties such as the density, specific heat capacity, and micro-hardness of galena ore lumps purchased from the public market were determined. The microscopic study, using the scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), confirmed that the as-received galena ore was mostly lead sulfide (PbS). The XRD pattern of the galena powder also elucidated that all the peaks were assigned to PbS. In addition, the as-received galena was roughly crushed, and fine-milled using a high-vibration milling machine with tungsten carbide rings. Nanoscale particles of about 90 nm were produced in a very short milling time of around 15 min. The obtained nanoscale powder was well investigated in the SEM at low and high magnifications to assess the exact range of particle size. Meanwhile, the SEM was employed to investigate the microstructure of sintered samples, where a part of the milled galena powder was compacted and sintered at 700 °C for 2 h. Again, the result of this investigation proved the formation of PbS with even smaller grain size compared with the grain size of the starting galena ore. A high relative sinter density of approximately 97% for galena powder was achieved by sintering under vacuum.

This study was conducted to investigate the effect of cobalt complexation on the spectral properties of anthocyanins (AC) extracted from black grape pomace (Black Magic) and the effect of complexation on the pH stability of AC during storage. Initially, cobalt acetate tetrahydrate aqueous solution was complexed with AC crude extract and diluted separately in buffer solutions with different pH (3.5, 4.5, 5.5, and 6.5). Afterward, spectral changes were determined spectrophotometrically. pH stability was investigated using the same buffer solutions and stored for 7 days in the dark at room temperature, and the absorbance of each solution was measured daily using a spectrophotometer. Results indicated that complexation caused similar hypsochromic and hyperchromic shifts in λ max at all pH values. With regard to pH stability, the degradation of complexed AC followed first-order reaction kinetics causing half-lives to increase up to 80-fold as compared with noncomplexed AC, which was due to the sharp decrease in K (per day), indicating an improved pH stability as compared with noncomplexed AC. Therefore, Co(II) could be used in the stabilization of grape AC for the coloration of a wide range of foods and food products at near-neutral pH environments considering the health benefits of grape AC and the maximum nontoxic dose of Co(II) salt., Competing Interests: AUTHOR DISCLOSURE STATEMENT The authors declare no conflict of interest., (Copyright © 2022 by The Korean Society of Food Science and Nutrition. All rights Reserved.)

Dibromomesitylene (DBMH) is one of the few molecules in which a methyl group is a quasi-free rotor in the crystal state. Density functional theory calculations - using the Born-Oppenheimer approximation (BOa) - indicate that in isolated DBMH, Me4 and Me6 are highly hindered in a 3-fold potential V 3 > 55 meV while Me2 symmetrically located between two Br atoms has a small 6-fold rotation hindering potential: V 6 ∼ 8 meV. Inelastic neutron scattering studies have shown that this is also true in the crystal, the Me2 tunneling gap being 390 μeV at 4.2 K and V 6 ∼ 18 meV. In the monoclinic DBMH crystal, molecules are packed in an anti-ferroelectric manner along the oblique a axis, favoring strong van der Waals interactions, while in the corrugated bc planes each molecule has a quasi hexagonal environment and weaker interactions. This results in the nearby environment of Me2 only being composed of hydrogen atoms. This explains why the Me2 rotation barrier remains small in the crystal and mainly 6-fold. Using the same potentials in the Schrödinger equation for a -CD 3 rotor has allowed predicting a tunneling gap of 69 μeV for deuterated Me2 in very good agreement with inelastic neutron scattering measurements. Therefore, because of a rare and unexpected local symmetry in the crystal, the Me2 rotation barrier remains small and 6-fold and hydrogen nuclei are highly delocalized and not relevant to the Born-Oppenheimer approximation. This and the neglect of spin states explain the failure of density functional theory calculations for finding the rotation energy levels of Me2.

Periodontitis comprises a chronic inflammation that is initiated by microbiota biofilm. If left untreated, periodontitis may lead to permanent tooth loss. Herein, we propose to design and improve a localized form of therapy comprising a chlorhexidine-impregnated hydrogel. Hydrogel films were prepared by varying the ratio between cellulose (MCC) and carboxymethylcellulose sodium (CMC) using the crosslinker epichlorohydrin (ECH). The hydrogel was loaded with chlorhexidine. Increasing the CMC ratio led to a reduction in the number of pores, an increase in their size, lower glass transition temperature ( T g ), decreased Young's modulus, and increased film stretching and affected the time of release. Bacterial and fungal zones of inhibition showed similar activity and were not affected by the CMC and MCC ratio. Hydrogels loaded with chlorhexidine prevented the growth of S. oralis and C. albicans microorganisms and may provide a promising local delivery system for treating periodontitis., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Ola Tarawneh et al.)

Activated carbon (BC) prepared from olive oil solid waste (olive husk) by slow pyrolysis was chemically activated using MgCl 2 (BC-MgCl 2 ). The BC and BC-MgCl 2 were used as adsorbents for removal of three phenolic compounds, namely, phenol (P), p-methoxyphenol (PMP) and p-nitrophenol (PNP), from aqueous solution. The uptake of these three phenolic compounds by the BC and BC-MgCl 2 was better expressed by the Langmuir and Dubinin-Radushkevich (D-R) isotherm models than by the Freundlich isotherm, and the kinetics of the adsorption process followed the pseudo-second order kinetic model. The maximum monolayer adsorption capacity of P, PMP and PNP were increased from 24.938, 45.455 and 61.728 on BC to 43.860, 98.039 and 121.951 mg/g on BC-MgCl 2 by factors of 1.76, 2.16 and 1.98, respectively. Therefore, the chemical activation of BC by MgCl 2 is indeed of importance for improving its adsorption performances. For both adsorbents, the adsorption phenomenon for different substituted phenols is a strong function of solubility, polarity, molecule structure, and size. At the tested temperatures (25, 35 and 45 °C), the negative values of ΔG° and positive values of ΔH° and ΔS° for the adsorption of P, PMP and PNP on BC and BC-MgCl 2 demonstrated that the adsorption was a spontaneous, endothermic and entropy-increasing process.

In this study, Jordanian diatomaceous earth (JDA) and commercial diatomaceous earth (standard diatomaceous earth, SDA) were used for adsorption of samarium (Sm)(III) and neodymium (Nd)(III) ions from aqueous solutions using batch technique as a function of initial concentration of metal ions, adsorbent dosage, ionic strength, initial pH solution, contact time, and temperature. Both adsorbents were characterized by Fourier transform infrared (FTIR), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area, and cation exchange capacity (CEC). Maximum metal ion uptake was observed after 100 min of agitation, and the uptake has decreased with increasing temperature and reached a maximum at pH ≈ 5. Different types of adsorption isotherms and kinetic models were used to describe the Nd(III) and Sm(III) ion adsorption. The experimental data fitted within the following isotherms in the order Langmuir > Dubinin-Radushkevich (DR) > Freundlich and the pseudo-second-order kinetic model based on their coefficient of determination (R 2 ), chi-square (χ 2 ), and error function (F error% ) values. Maximum adsorption uptakes, according to the Langmuir model, were obtained as 188.679 mg/g and 185.185 mg/g for Sm(III) and 169.492 mg/g and 149.254 mg/g for Nd(III) by JDA and SDA, respectively. The results of thermodynamic parameters showed that the adsorption of Sm(III) and Nd(III) ions onto JDA and SDA is a feasible, spontaneous, exothermic, and entropy driven. The best recovery for Sm(III) and Nd(III) was obtained when the 0.05 M EDTA + 0.05 M H 3 PO 4 mixture was used as an eluent.

Biochar samples were prepared from pine fruit shell (PFS) biomass using slow pyrolysis for 1 h at three different temperatures (350, 450 and 550°C). Batch experiments were carried out for the biosorption of phenol onto these biochars. The effect of biosorption experimental parameters such as adsorbent dosage, ionic strength, initial solution pH, contact time and temperatures has been investigated. Experimental equilibrium data were fitted to Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms by non-linear regression method. The experimental kinetic data were also fitted to Lagergren pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models by non-linear regression method. Determination coefficient (R 2 ), chi-squared (χ 2 ) and error function (F error% ) were used to determine the optimum isotherm and kinetic by non-linear regression method. Kinetics results were best described by pseudo-second order model for phenol onto three biochars. Thermodynamic parameters were estimated and implied that the adsorption process is spontaneous and exothermic in nature., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Cellulose/polypyrrole and cellulose/polypyrrole-TiO 2 composites were prepared via in situ oxidative chemical polymerization of pyrrole using FeCl 3 as oxidant. The concentration effect of pyrrole on the structure and properties of prepared matrix has been investigated. Furthermore, the structure of the prepared materials was characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Thermal gravimetrical analysis (TGA). The results exhibited that the addition of cellulose and TiO 2 increase the thermal stability of the polypyrrole system. Moreover, dielectric properties of the obtained composites were studied over frequency range from 42Hz to 5MHz. The electrical measurements including dielectric constant, ε'(ω), dielectric loss, ε''(ω), loss tangent, tan δ and ac conductivity, σac were carried., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Solid waste from Jordanian olive oil processing (OOSW) was used to prepare biochar samples by slow pyrolysis at terminal temperatures of 350, 450, 550 and 630 °C; henceforth known as BC-350, BC-450, BC-550 and BC-630, respectively. These samples were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction, ash content, moisture content and surface area. The ability of the biochar to remove Hg 2+ ions from aqueous solutions was investigated in laboratory scale batch experiments. The kinetics, effect of pH and temperature were studied. The optimum pH value for Hg 2+ adsorption was 5. Dubinin-Radushkevich (D-R) isotherm model was the best fit for the experimental results. Based on the D-R model, the maximum adsorption capacities at 25 °C were 84.93, 94.48, 96.11 and 104.59 mg.g -1 , for BC-350, BC-450, BC-550 and BC-630, respectively. The pseudo-second-order kinetic model was a good fit for the experimental data. The calculated change in free energy ΔG and enthalpy ΔH indicated that the adsorption process was spontaneous and exothermic in nature. The positive value of ΔS showed increased randomness of the solid/solution interface during the adsorption. The results indicated that biochar derived from OOSW can be a good adsorbent for treatment of water contaminated with Hg 2+ .