Calcium and strontium thiobarbiturates with discrete and polymeric structures

Rheological Characterization of Genipin-Based Crosslinking Pigment and O-Carboxymethyl Chitosan-Oxidized Hyaluronic Acid In Situ Formulable Hydrogels

The aim of this study was to develop a material capable of rapidly absorbing bodily fluids and forming a resilient, adhesive, viscoelastic hydrogel in situ to prevent post-surgical adhesions. This material was formulated using O-carboxymethyl chitosan (O-CMCS), oxidized hyaluronic acid (OHA), and a crosslinking pigment derived from genipin and glutamic acid (G/GluP). Both crosslinked (O-CMCS/OHA-G/GluP) and non-crosslinked hydrogels (O-CMCS/OHA) were evaluated using a HAAKE™ MARS™ rheometer for their potential as post-surgical barriers. A rheological analysis, including dynamic oscillatory measurements, revealed that the crosslinked hydrogels exhibited significantly higher elastic moduli (G'), indicating superior gel formation and mechanical stability compared to non-crosslinked hydrogels. The G/GluP crosslinker enhanced gel stability by increasing the separation between G' and G″ and achieving a lower loss tangent (tan δ < 1.0), indicating robustness under dynamic physiological conditions. The rapid hydration and gelation properties of the hydrogels underscore their effectiveness as physical barriers. Furthermore, the O-CMCS/OHA-G/GluP hydrogel demonstrated rapid self-healing and efficient application via spraying or spreading, with tissue adherence and viscoelasticity to facilitate movement between tissues and organs, effectively preventing adhesions. Additionally, the hydrogel proved to be both cost effective and scalable, highlighting its potential for clinical applications aimed at preventing post-surgical adhesions.

C2H12N6C4O4·2H2O and Na2C4O4·3H2O: Two Ultraviolet Birefringent Compounds with the [C4O4]2- Group

In modern optics, birefringent materials that can manipulate light polarization play important roles in lasers and information fields. The search for ultraviolet (UV) crystals with large birefringence is the focus of attention in the field of optical materials. In this work, we synthesized two birefringent crystals, C2H12N6C4O4·2H2O and Na2C4O4·3H2O, containing planar π-conjugated [C4O4]2- groups. Attributed to the large structural anisotropy and relatively ordered arrangement of the [C4O4]2- groups, C2H12N6C4O4·2H2O and Na2C4O4·3H2O possess large birefringence of 0.20-0.21 at 1064 nm. Meanwhile, they exhibit short ultraviolet cutoff edges at about 280-300 nm, corresponding to the large band gaps of 4.35 and 4.24 eV, respectively. Using structural analysis and first-principles calculations, the origins of such large birefringence are investigated and discussed. This work provides two potential UV birefringent crystals and prompts the search for novel birefringent materials.

Study of the Effect of Baicalin from Scutellaria baicalensis on the Gastrointestinal Tract Normoflora and Helicobacter pylori

The antimicrobial properties of baicalin against H. pylori and several probiotic cultures were evaluated. Baicalin was isolated from a dry plant extract obtained by extraction with water at 70 °C. For isolation, extraction was carried out with n-butanol and purification on a chromatographic column. The antimicrobial potential was assessed by evaluating changes in the optical density of the bacterial suspension during cultivation; additionally, the disk diffusion method was used. During the study, the baicalin concentrations (0.25, 0.5, and 1 mg/mL) and the pH of the medium in the range of 1.5-8.0 were tested. The test objects were: suspensions of H. pylori, Lactobacillus casei, L. brevis, Bifidobacterium longum, and B. teenis. It was found that the greater the concentration of the substance in the solution, the greater the delay in the growth of the strain zone. Thus, the highest antimicrobial activity against H. pylori was observed at pH 1.5-2.0 and a baicalin concentration of 1.00 mg/mL. In relation to probiotic strains, a stimulating effect of baicalin (1.00 mg/mL) on the growth of L. casei biomass at pH 1.5-2.0 was observed. The results open up the prospects for the use of baicalin and probiotics for the treatment of diseases caused by H. pylori.

Effect of Dy3+ and Tb3+ Rare-Earth Cation Co-Substitution on the Structure, Magnetic, and Magnetostrictive Properties of Ni-Co-Ferrites

The design and development of electromagnetic and magnetoelectric materials with enhanced properties and performance are desirable for numerous technologies, which are based on integrated electromagnetic materials and components. Nevertheless, engineering the crystalline materials with multi-complex chemistry and multiple cations is challenging. In this context, herein, we report on the effect of rare-earth (RE) cations, namely, Dy³⁺ and Tb³⁺, co-substituted into the Co-Ni-mixed ferrite materials for applications in stress/torque sensors. The RE-cations that co-substituted Co-Ni-ferrite materials with a composition of Ni_0.8Co_0.2Fe_2-x(Dy_1-yTb_y)_xO₄ (x = 0-0.1, y = 0.3; NCFDT) were prepared by the high-temperature solid-state chemical reaction method. The effect of variable composition (x) on the structure, morphology, chemical bonding, and magnetic properties of NCFDT materials is investigated in detail, and the structure-property optimization enabled realizing magnetostrictive NCFDT for sensor applications. X-ray diffraction analysis coupled with Rietveld refinement confirms the face-centered cubic crystal structure. Chemical bonding analysis made using Raman spectroscopic and Fourier transform infrared spectroscopic measurements validates the active modes corresponding to the spinel ferrite structure. The effect of Dy³⁺ and Tb³⁺ substitution is primarily seen in the grain size (range of 5-15 μm), as evident from the scanning electron microscopy patterns. Energy-dispersive spectroscopy confirms the presence of all constituent elements with expected composition and without any impurities. The magnetic property measurements indicate that the remnant magnetization (M_r) increases from 0.06 to 0.17 μ_B/f.u. with the rare-earth (Dy and Tb) substitution and has achieved the maximum squareness ratio (M_r/M_s) = 0.097 at x = 0.10. To validate their application potential in magneto-mechanical sensors, we have measured the magnetostriction coefficients (λ₁₁ and λ₁₂), which demonstrate high values of λ₁₁ = -92 ppm (along the parallel direction) and λ₁₂ = 66 ppm (along the perpendicular direction) for NCFDT with x = 0.05 at H = 7000 Oe. In addition, the maximum value of strain sensitivity is observed, particularly dλ11dH = -0.764 nm/A whereas dλ12dH = 0.361 nm/A. The correlation between strain sensitivity (dλ/dH) and susceptibility (dM/dH), as derived from magnetostriction and magnetization measurements, respectively, is established. The outcomes of this study indicate that Ni-Co-ferrites with Dy³⁺ and Tb³⁺ substitution are suitable for stress/torque sensors. These NCFDT ferrites may also be useful as a necessary constitutive phase for the manufacture of magnetoelectric composite materials, making them appropriate for magnetic field sensors and energy harvesting applications.

Microwave-assisted synthetic method of novel Bi2O3 nanostructure and its application as a high-performance nano-catalyst in preparing benzylidene barbituric acid derivatives

In this study, controllable and optimal microwave irradiation has been used to synthesize the novel nanostructures of Bi₂O₃ under environmental conditions. The final products had a thermal stability of 210°C, an average particle size distribution of 85 nm, and a surface area of 783 m²/g. The high thermodynamic stability of Bi₂O₃ nanostructures was confirmed by TG and differential scanning calorimetry (DSC) analyses. The nanostructure nature of compounds, and most importantly, the use of an effective, cost-effective, and rapid synthesis route of microwave have created significant physiochemical properties in the Bi₂O₃ products. These unexpected properties have made the possibility of potential application of these products in various fields, especially in nano-catalyst applications. It is well-documented that, as Lewis acid, bismuth nano-catalyst exhibits a great catalytic activity for the green synthesis of some bio-active barbituric acid derivatives using precursors with electron-donating or electron-withdrawing nature in high yields (80%–98%). After incorporating this catalyst into the aqueous media, all the reactions were completed within 2–3 min at room temperature. The main advantages of this method are practical facility, the availability of starting materials, and low costs besides the catalyst reusability. Additionally, the catalyst synthesis process may be carried out in the aqueous media for a short period with medium to high yields. The obtained results have opened a new window for the development of a novel nano-catalyst with practical application.

Synthesis and Characterization of Monodispersed Spherical Calcium Oxide and Calcium Carbonate Nanoparticles via Simple Pyrolysis

In this study, calcium carbonate nanoparticles (CCNPs) and calcium oxide nanoparticles (CONPs) are synthesized by the carbonization/calcination of calcium oleate. CONPs are an essential inorganic material, and they are used as catalysts and as effective chemisorbents for toxic gases. CCNPs are widely used in plastics, printing ink, and medicines. Here, calcium oleate is used as a starting material for the preparation of CCNPs and CONPs. This calcium oleate is prepared from calcium hydroxide and oleic acid in ethanol under mild reflux conditions. The effect of the calcination temperature of calcium oleate is examined during the synthesis of CCNPs and CONPs. By simple carbonization/calcination, calcite-type CCNPs and CONPs are prepared at <550 °C and >600 °C, respectively. The synthesized nanomaterials are analyzed by various physicochemical characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) with derivative thermogravimetry (DTG), and scanning electron microscopy (SEM) with energy dispersive X-ray analysis. An X-ray diffractometer and the Scherrer formula are used to analyze the crystalline phase and crystallite size of prepared nanoparticles. TGA techniques confirm the thermal stability of the calcium oleate, CCNPs, and CONPs. The SEM analysis illustrates the dispersive behavior and cubic/spherical morphologies of CCNPs/CONPs. Furthermore, the obtained results are compared to the CCNP and CONP samples prepared using calcium hydroxide. As a result, the carbonization/calcination of calcium oleate produces monodispersed CONPs, which are then compared to the CONPs from calcium hydroxide. Additionally, from calcium oleate, CONPs can be prepared on a large scale in a cheap, convenient way, using simple equipment which can be applied in various applications.

Sustainable Green Synthesis of Yttrium Oxide (Y2O3) Nanoparticles Using Lantana camara Leaf Extracts: Physicochemical Characterization, Photocatalytic Degradation, Antibacterial, and Anticancer Potency

Due to their appropriate physicochemical properties, nanoparticles are used in nanomedicine to develop drug delivery systems for anticancer therapy. In biomedical applications, metal oxide nanoparticles are used as powerful and flexible multipurpose agents. This work described a green synthesis of Y₂O₃ nanoparticles (NPs) using the sol-gel technique with the use of aqueous leaf extracts of Lantana camara L (LC). These nanoparticles were characterized with the aid of different methods, including UV, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), transmitted electron microscopy (TEM), and photocatalytic degradation. Y₂O₃ nanoparticles showed excellent antibacterial activity against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli with a 10 to 15 mm inhibitory zone. Green Y₂O₃ NPs were released with a 4 h lag time and 80% sustained release rate, indicating that they could be used in drug delivery. In addition, the bioavailability of green Y₂O₃ NPs was investigated using cell viability in cervical cancer cell lines. These green-synthesized Y₂O₃ NPs demonstrated photocatalytic degradation, antibacterial, and anticancer properties.

Enhanced Photocatalytic Activity of WS2/TiO2 Nanofibers for Degradation of Phenol under Visible Light Irradiation

Binary composite WS2/TiO2 nanofibers (WTN) were elaborated by electrospinning technique. The photocatalytic efficiency of the binary nanofibers was changed via different ratios between WS2 and TiO2. The structural, morphological and optical properties of the prepared nanofibers were evaluated by Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and UV-Vis diffuse reflectance spectroscopy (UV-vis/DRS), respectively. The prepared nanofibers showed a remarkable performance in photocatalytic efficiency of phenol compound degradation under visible light. WTN nanofibers showed superior photocatalytic activity (83%) and high stability of several cycles under visible light. Therefore, WS2/TiO2 nanofibers have great prospects for the treatment of wastewater from toxic organic contamination due to their excellent photocatalytic performance reusability and recyclability.

Upconversion Properties and Temperature-Sensing Behaviors of Alkaline-Earth-Metal Scandate Nanocrystals Doped with Er3+/Yb3+ Ions in the Presence of Alkali Ions (Li+, Na+, and K+)

Temperature-sensing media based on the fluorescence intensity ratio (FIR) of upconversion materials that suffer from low sensitivity owing to the small energy gap still have a need for new compounds with strong upconversion luminescence (UCL). In this work, a series of MSc₂O₄:Er³⁺/Yb³⁺ (M = Mg, Ca, Sr, and Ba) nanocrystals were prepared by a hydrothermal method using NaOH alkaline solution. The structure, morphology, and UCL characteristics of materials were investigated, and the red UCL of the CaSc₂O₄:Er³⁺/Yb³⁺ sample was dramatically enhanced by a factor of ∼12, ∼23, and ∼2000 compared with SrSc₂O₄, MgSc₂O₄, and BaSc₂O₄ samples, respectively. By adjusting alkali ions (Li⁺, Na⁺, K⁺), the UCL intensities of CaSc₂O₄:Er³⁺/Yb³⁺ and SrSc₂O₄:Er³⁺/Yb³⁺ samples were further improved, especially in the presence of Li⁺ ions. Excellent temperature-sensing behaviors are realized for CaSc₂O₄:Er³⁺/Yb³⁺ and SrSc₂O₄:Er³⁺/Yb³⁺ samples in the presence of Li⁺ ions, in which the maximum absolute sensitivity S_A values are about 0.0041 and 0.0036 K^-1 at 600 K and the corresponding relative sensitivity S_R values are expressed as 1197/T² and 1129/T² (the current optimal S_R = 1289/T²), respectively. The intense UCL and excellent S_A and S_R values indicate that CaSc₂O₄:Er³⁺/Yb³⁺ and SrSc₂O₄:Er³⁺/Yb³⁺ materials are promising candidates for application in high-temperature sensors working under 980 nm excitation.

Microwave assisted Synthesis of ZnGa2-x-yEuxTbyO4 luminescent nanoparticles showing balanced white-light emission

Phosphor-converted white-light-emitting diodes (pc-WLED) are technologically advanced next-generation lighting sources which will potentially substitute traditional lighting. Herein, we report microwave-assisted synthesis of single-phase, ZnGa2-x-yEuxTbyO4 nanophosphor in 10 min with high...

A two-dimensional calcium (II) coordination polymer constructed from 2,2'-[terephthaloylbis(azanediyl)]diacetate: synthesis, structure and properties

A new two-dimensional (2D) coordination polymer, namely, poly[[diaqua-[μ₄-2,2'-[terephthaloylbis(azanediyl)]diacetato]calcium(II)] monohydrate], {[Ca(C₁₂H₁₀N₂O₆)(H₂O)₂]·H₂O}_n, (I), has been synthesized by the reaction of CaCl₂ with 2,2'-[terephthaloylbis(azanediyl)]diacetic acid (H₂L). The title compound was structurally characterized by single-crystal X-ray diffraction analysis, elemental analysis and IR spectroscopy. In the crystal structure of (I), each Ca^II cation binds to six carboxylate groups from four symmetry-related L^2- dianions. The hexadentate L^2- ligand links four symmetry-related calcium cations into a 2D layer-like structure, which can be simplified as a uninodal SP 2-periodic (3,6)III net with the point symbol (4³·6³). In the lattice, all layers pack in parallel arrays through weak interlayer hydrogen bonding and π-π interactions. The thermal stability and photoluminescence properties of (I) have been investigated. Thermogravimetric analysis reveals the different thermal stabilities of the two coordinated water molecules due to their different hydrogen-bonding interactions. The title coordination polymer exhibits an excitation-wavelength-dependent fluorescence in the solid state.

Exploring the FTIR, Optical and Nuclear Radiation Shielding Properties of Samarium-Borate Glass: A Characterization through Experimental and Simulation Methods

(Tl₂O₃)₃₀-(Li₂O)₁₀-(B₂O₃)_(60−y)-(Sm₂O₃)_y glass system with various Sm₂O₃ additives (y = 0, 0.2, 0.4, 0.6) was studied in detail. The vibrational modes of the (Tl₂O₃)₃₀-(Li₂O)₁₀-(B₂O₃)_(60−y) network were active at three composition-related IR spectral peaks that differed from those mixed with Samarium (III) oxide at high wavenumber ranges. These glass samples show that their permeability increased with the Samarium (III) oxide content increase. Additionally, the electronic transition between localized states was observed in the samples. The MAC, HVL, and Zeff values for radiation shielding parameters were calculated in the energy range of 0.015–15 MeV using the FLUKA algorithm. In addition, EBF, EABF, and Σ_R values were also determined for the prepared glasses. These values indicated that the parameters for shielding (MAC, HVL, Z_eff, EBF, EABF, and Σ_R) are dependent upon the Samarium (III) oxide content. Furthermore, the addition of Samarium (III) oxide to the examined glass samples greatly reinforced their shielding capacity against gamma photon. The findings of the current study were compared to analyses of the XCOM software, some concretes, and lead. In the experiment, it was found that the SMG0.6 glass sample was the strongest shield.

Effects of hydrothermal temperatures on crystalline quality and photoluminescence properties of β-Ga2O3 microspheres using ammonia as a precipitator

β-Ga₂O₃ microspheres were synthesized by a hydrothermal method.

Hydrogen bonding from crystalline water mediates the hydration/dehydration of mequitazine glycolate

Comparison of crystal structures, dynamic vapor adsorption measurements, lattice energy calculations and structural optimization of the dehydration model were used to evaluate the hydration-dehydration behavior.

“Old dog, new tricks”: the lone pair effect inducing divergent optical responses in lead cyanurates containing π-bonds

The stereochemically active lone pair effect of Pb²⁺ and induced narrower bandgaps were elaborated in Pb₃(HC₃N₃O₃)₂(OH)₂ for the first time.

Influence of post-deposition annealing on structural, morphological and optical properties of copper (II) acetylacetonate thin films

In this study, the effect of thermal annealing under vacuum conditions on structural, morphological and optical properties of thermally evaporated copper (II) acetylacetonate, cu(acac)₂, thin films were investigated. The copper (II) acetylacetonate thin films were deposited using thermal evaporation technique at vacuum pressure ~1 × 10^-5 mbar. The deposited films were thermally annealed at 323, 373, 423, and 473 K for 2 h in vacuum. The thermogravimetric analysis of cu(acac)₂ powder indicated a thermal stability of cu(acac)₂ up to 423 K. The effects of thermal annealing on the structural properties of cu(acac)₂ were evaluated employing X-ray diffraction method and the analysis showed a polycrystalline nature of the as-deposited and annealed films with a preferred orientation in [1¯01] direction. Fourier transformation infrared (FTIR) technique was used to negate the decomposition of copper (II) acetylacetonate during preparation or/and annealing up to 423 K. The surface morphology of the prepared films was characterized by means of field emission scanning electron microscopy (FESEM). A significant enhancement of the morphological properties of cu(acac)₂ thin films was obtained till the annealing temperature reaches 423 K. The variation of optical constants that estimated from spectrophotometric measurements of the prepared thin films was investigated as a function of annealing temperature. The annealing process presented significantly impacted the nonlinear optical properties such as third-order optical susceptibility χ⁽³⁾ and nonlinear refractive index n₂ of cu(acac)₂ thin films.