Powder X-ray Diffraction Studies Research Articles

Synergistic Influence of Doping and Co‐Doping of Trivalent Ions (La+3 and Al+3) on YFeO3 Nanomaterials

Herein, the structural, optical, and magnetic properties of Y0.85La0.15FexAlyO3: (x; y) where x = 1; y = 0, x = 0.975; y = 0.025, x = 0.95; y = 0.05, and x = 0.9; y = 0.1 nanomaterials obtained from sol–gel method are reported. The X‐ray powder diffraction (XRD) for the structural characterization, scanning electron microscopy for crystallite size estimation, ultraviolet–visible absorption for optical studies, and vibrating‐sample magnetometer for magnetic studies are used in this investigation. An increase of orthorhombic crystal structure with an increase of Al content in the sample is observed from XRD studies. The existence of all the elements present in the samples is observed from energy‐dispersive X‐ray spectroscopy. The optical bandgap increases from 2.04 to 2.10 eV with an increase of Al concentration from 0 to 0.05. The observed magnetization value is 3.14 emu g−1 for y = 0.05, which is higher than y = 0 (2.11 emu g−1) and y = 0.024 (2.58 emu g−1). In summary, the obtained result (x = 0.95; y = 0.05) can be useful for different magnetic‐based applications.

Synergistic Influence of Doping and Co‐Doping of Trivalent Ions (La+3 and Al+3) on YFeO3 Nanomaterials

Herein, the structural, optical, and magnetic properties of Y0.85La0.15FexAlyO3: (x; y) where x = 1; y = 0, x = 0.975; y = 0.025, x = 0.95; y = 0.05, and x = 0.9; y = 0.1 nanomaterials obtained from sol–gel method are reported. The X‐ray powder diffraction (XRD) for the structural characterization, scanning electron microscopy for crystallite size estimation, ultraviolet–visible absorption for optical studies, and vibrating‐sample magnetometer for magnetic studies are used in this investigation. An increase of orthorhombic crystal structure with an increase of Al content in the sample is observed from XRD studies. The existence of all the elements present in the samples is observed from energy‐dispersive X‐ray spectroscopy. The optical bandgap increases from 2.04 to 2.10 eV with an increase of Al concentration from 0 to 0.05. The observed magnetization value is 3.14 emu g−1 for y = 0.05, which is higher than y = 0 (2.11 emu g−1) and y = 0.024 (2.58 emu g−1). In summary, the obtained result (x = 0.95; y = 0.05) can be useful for different magnetic‐based applications.

Transdermal Hydrogen Sulfide Delivery Enabled by Open-Metal-Site Metal-Organic Frameworks.

Hydrogen sulfide (H2S) is an endogenously produced gasotransmitter involved in many physiological processes that are integral to proper cellular functioning. Due to its profound anti-inflammatory and antioxidant properties, H2S plays important roles in preventing inflammatory skin disorders and improving wound healing. Transdermal H2S delivery is a therapeutically viable option for the management of such disorders. However, current small-molecule H2S donors are not optimally suited for transdermal delivery and typically generate electrophilic byproducts that may lead to undesired toxicity. Here, we demonstrate that H2S release from metal-organic frameworks (MOFs) bearing coordinatively unsaturated metal centers is a promising alternative for controlled transdermal delivery of H2S. Gas sorption measurements and powder X-ray diffraction (PXRD) studies of 11 MOFs support that the Mg-based framework Mg2(dobdc) (dobdc4- = 2,5-dioxidobenzene-1,4-dicarboxylate) is uniquely well-suited for transdermal H2S delivery due to its strong yet reversible binding of H2S, high capacity (14.7 mmol/g at 1 bar and 25 °C), and lack of toxicity. In addition, Rietveld refinement of synchrotron PXRD data from H2S-dosed Mg2(dobdc) supports that the high H2S capacity of this framework arises due to the presence of three distinct binding sites. Last, we demonstrate that transdermal delivery of H2S from Mg2(dobdc) is sustained over a 24 h period through porcine skin. Not only is this significantly longer than sodium sulfide but this represents the first example of controlled transdermal delivery of pure H2S gas. Overall, H2S-loaded Mg2(dobdc) is an easily accessible, solid-state source of H2S, enabling safe storage and transdermal delivery of this therapeutically relevant gas.

Hexagonal rod-like Eu3+ doped CaMoO4 phosphors: Structural, photoluminescence and photometric properties for display device applications

A multicolored LED illumination device is a compact, durable, easy to obtain color-adjustable output illumination source. It is frequently utilized in the domains of room illumination and exterior displays. However, the advancement of multicolor LEDs has been hampered by the rise in price and the fall in luminous efficacy while changing illumination colors. In the present investigation we have prepared intense red emitting Eu3+ doped CaMoO4 phosphor nanopowders via simple solid-state reaction technique. The powder X-ray diffraction (PXRD) studies reveal the crystalline nature of the samples with scheelite–type mono phase tetragonal structure with I41/a space group. The band gap (Eg) energy values were estimated and found to range between 4.63-5.32 eV. Scanning electron microscopy (SEM) studies reveled the hexagonal rod-like structures with different Aloe Vera gel concentrations. The particle size was found to be around 40 nm. The vibrational modes of the prepared powders were evaluated by using Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. It was observed from the results that, there were 26 vibrational modes of CaMoO4 (Γ=3Ag + 5Au + 5Bg + 3Bu + 5Eg + 5Eu) 8 of which (4Au and 4Eu) were infrared active and 13 (Ag, Bg, and Eg) are Raman active. Photoluminescence (PL) emission intensity increases up to 5 mol% of Eu3+ ions load and subsequently it declines due to the concentration quenching phenomenon and effective energy transfer from Mo-O charge transfer band (CTB) to 5D0 levels of Eu3+. It was noticed from PL emission spectra that, four intense peaks located at 5D0 → 7F1 (590 nm), 5D0 → 7F2 (613 nm), 5D0 → 7F3 (654 nm), 5D0 → 7F4 (702 nm) of Eu3+ respectively. The Commission International de I'Eclairage (CIE) diagram indicates the red color emission and average correlated color temperature (CCT) value was found to be 2050 K. Further, the external quantum efficiency (QE) and color purity (CP) were calculated to check the phosphor efficiency and found to be 92% and 72% respectively. The present investigation opens up a new avenue in the fabrication of low-cost display devices with high color purity and luminous efficacy.

Deciphering the influence of support in the performance of NiFe2O4 catalyst for the production of hydrogen fuel and nanocarbon by methane decomposition

Wet chemical synthesis route was used to synthesis nickel ferrite (NiFe2O4) nanoparticle. Later on the synthesized NiFe2O4 were supported on the surface of three traditional supports such as Al2O3, MgO and TiO2 to get NiFe2O4/Al2O3, NiFe2O4/TiO2 and NiFe2O4/MgO catalysts. The activity profile of each catalyst was evaluated in a fixed-bed reactor for direct methane decomposition at 800 °C. For both fresh and spent catalysts, many characterization techniques have been employed mainly XRD, FESEM, HRTEM, Raman spectroscopy, TGA, and nitrogen adsorption-desorption isotherm. X-ray powder diffraction studies revealed that all synthesized catalysts have a cubic spinel crystal structure. The XRD confirm the presence of NiFe2O4 particles in the component of fresh NiFe2O4/MgO, NiFe2O4/TiO2 and NiFe2O4/Al2O3 catalysts. Temperature Program Reduction (TPR) unveiled the presence of Ni oxides and Fe oxides by displaying reduction peaks in their respective temperature regions. The N2 adsorption-desorption isotherms of the fresh all catalysts reveal that these catalysts have a mesoporous structure. Activity data concluded NiFe2O4/MgO to be the most active catalysts among the tested catalysts methane conversion magnitude of 41.13 % and H2 formation rate of 84.40 × 10−5 mol H2 g−1 min−1. On the other hand, the H2 formation rate drastically declined and very poor activity of both NiFe2O4/TiO2 and NiFe2O4/Al2O3 catalysts was observed in the current work. XRD patterns, FESEM images and TGA analysis of spent NiFe2O4/MgO catalyst shown the filamentous carbon formation which secondarily confirm its higher activity, while its absence in catalysts of NiFe2O4/TiO2 and NiFe2O4/Al2O3. TGA analysis of the carbon deposited on the NiFe2O4/MgO catalyst showed that the amount of carbon was approximately 64 wt%. It was suggested that the formation of nickel-iron carbide revealed by XRD studies of spent catalysts may be the factor related to their poor activity while discussing the structure-activity relationship. Likewise, the higher degree of dispersion related to NiFe2O4/MgO as displayed by XRD, FESEM and TPR investigations, played a vital role in accelerating the rate of hydrogen formation.

Tailoring thermoelectric performance of n-type Bi2Te3 through defect engineering and conduction band convergence

Bi2Te3, an archetypical tetradymite, is recognised as a thermoelectric (TE) material of potential application around room temperature. However, large energy gap (ΔEc ) between the light and heavy conduction bands results in inferior TE performance in pristine bulk n-type Bi2Te3. Herein, we propose enhancement in TE performance of pristine n-type Bi2Te3 through purposefully manipulating defect profile and conduction band convergence mechanism. Two n-type Bi2Te3 samples, S1 and S2, are prepared by melting method under different synthesis condition. The structural as well as microstructural evidence of the samples are obtained through powder x-ray diffraction and transmission electron microscopic study. Optothermal Raman spectroscopy is utilized for comprehensive study of temperature dependent phonon vibrational modes and total thermal conductivity ( κ ) of the samples which further validates the experimentally measured thermal conductivity. The Seebeck coefficient value is significantly increased from 235 μVK−1 (sample S1) to 310 μVK−1 (sample S2). This is further justified by conduction band convergence, where ΔEc is reduced from 0.10 eV to 0.05 eV, respectively. To verify the band convergence, the double band Pisarenko model is employed. Large power factor (PF) of 2190 μWm−1K−2 and lower κ value leading to ZT of 0.56 at 300 K is gained in S2. The obtained PF and ZT value are among the highest values reported for pristine n-type bulk Bi2Te3. In addition, appreciable value of TE quality factor and compatibility factor (2.7 V−1) at room temperature are also achieved, indicating the usefulness of the material in TE module.

Tuning of thermoelectric performance by modulating vibrational properties in Ni-doped Sb2Te3

Sb2Te3, a binary chalcogenide-based 3D topological insulator, attracts significant attention for its exceptional thermoelectric performance. We report the vibrational properties of magnetically doped Sb2Te3 thermoelectric material. Ni doping induces defect/disorder in the system and plays a positive role in engineering the thermoelectric properties through tuning the vibrational phonon modes. Synchrotron powder x-ray diffraction study confirms good crystalline quality and single-phase nature of the synthesized samples. The change in structural parameters, including B iso and strain, further corroborate with structural disorder. Detailed modification of phonon modes with doping and temperature variation is analysed from temperature-dependent Raman spectroscopic measurement. Compressive lattice strain is observed from the blue shift of Raman peaks owing to Ni incorporation in Sb site. An attempt is made to extract the lattice thermal conductivity from total thermal conductivity estimated through optothermal Raman studies. Hall concentration data support the change in temperature-dependent resistivity and thermopower. Remarkable increase in thermopower is observed after Ni doping. Simulation of the Pisarenko model, indicating the convergence of the valence band, explains the observed enhancement of thermopower in Sb2−x Ni x Te3. The energy gap between the light and heavy valence band at Γ point is found to be 30 meV (for Sb2Te3), which is reduced to 3 meV (in Sb1.98Ni0.02Te3). A significant increase in thermoelectric power factor is obtained from 715 μWm−1K−2 for pristine Sb2Te3 to 2415 μWm−1K−2 for Ni-doped Sb2Te3 sample. Finally, the thermoelectric figure of merit, ZT is found to increase by four times in Sb1.98Ni0.02Te3 than that of its pristine counterpart.

Structural, optical, second harmonic, and mechanical studies on zinc chloride added alpha-glycine crystals

The slow evaporation solution method was employed to synthesize and crystallize zinc chloride doped α-glycine (ZCAG) single crystals. The single crystal X-ray diffraction studies of pure α-glycine single crystals revealed that the structure belong to primitive monoclinic lattice. Powder X-ray diffraction studies of ZCAG showed the well-defined sharp peaks and formation of centrosymmetric structure with space group P21/n. The increase in lattice volume of ZCAG suggested that the access of zinc chloride into the α-glycine crystal and the entry of zinc chloride to the α-glycine crystal was also established from the energy-dispersive X-ray analysis. Fourier transform infrared spectrum of ZCAG revealed that the functional groups of α-glycine was not transformed due to the introduction of zinc chloride into the lattice. The optical transparency of ZCAG was observed in the UV-visible region, and it exhibited a superior transmittance in the visible region. Energy bandgap value was determined and found to changes while increasing the dopant concentration. An emission peak was observed in the violet region from the photoluminescence spectra. The centrosymmetric ZCAG exhibited second harmonic generation efficiency of 1.44 times higher than standard potassium dihydrogen phosphate, possibly due to local non-centrosymmetry in the lattice, which is further augmented by lattice distortion induced by the dopant. Low dielectric constant and loss of the grown ZCAG crystals showed the remarkable application of non-linear optical. The Meyer index indicates that the grown ZCAG are categorized as soft materials.

Ni Single Atom Decorated Porous Hollow Carbon Nanosphere-Based Electrodes for High Performance Symmetric Solid-State Supercapacitors.

Ni single atom containing hollow carbon nanospheres with nitrogen doping has been synthesized by carbonization of Ni(NO3)2/phloroglucinol-formaldehyde polymer/silica composite. The samples have been characterized by powder X-ray diffraction, nitrogen adsorption/desorption, electron microscopic, Raman and X-ray photoelectron spectroscopic studies. The microstructure and surface area vary with the amount of Ni(NO3)2 employed in the syntheses and the carbonization environment. An optimized amount of nickel and argon as the carbonization gas afford Ni-1.0@N@HCN-Ar which possesses overall superior features. The uniformly dispersed Ni single atoms within the hollow porous carbon framework fully utilize all the electroactive sites thereby improving the supercapacitive performance. The specific capacitance of Ni-1.0@N@HCN-Ar reaches 777 F g-1 at 1 A g-1 with a Coulombic efficiency of 98.4 % and excellent recyclability. The energy and power density of Ni-1.0@N@HCN-Ar are found to be high; at 1 A g-1 its energy density is 155.4 Wh kg-1 with a power density of 600.3 W kg-1. At a high current density of 10 A g-1 the material shows a high energy density of 118.4 Wh kg-1 with excellent power density of 6003.4 W kg-1. A symmetric solid-state supercapacitor assembled with this material, Ni-1.0@N@HCN-Ar//Ni-1.0@N@HCN-Ar using H2SO4/PVA gel electrolyte shows a superior energy density value of 30 Wh kg-1 at a power density of 1200 W kg-1.

Ni-Doped cerium oxide on rGO: A hydrothermal approach for high-performance supercapacitors

This work describes the hydrothermal method for synthesizing a novel nanocomposite: Nickel -doped Cerium oxide on reduced graphene oxide (Ni-CeO2/rGO). The resulting material exhibits exceptional electrocatalytic behavior, showing promise for supercapacitor applications. The Phase morphology, elemental analysis, surface area and oxidation state were confirmed by powder X-ray diffraction studies (PXRD), Raman spectrum, High Resolution Transmission Electron Microscopy (HRTEM), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX), Brunauer-Emmett Teller (BET) and XPS respectively. Electrochemical analysis involving cyclic voltammetry (CV), Galvanostatic charge/ discharge, and Electrochemical impedance spectroscopy (EIS). The specific capacitance is 262.1Fg-1, 504Fg-1, and 728Fg-1 for CeO2, CeO2/rGO, Ni-CeO2/rGO it depicts its suitability for energy storage. This study establishes the Ni-CeO2/rGO nanocomposite as a highly effective material for advanced energy storage applications.

Influence of pH on growth, structural, thermal, linear and nonlinear optical properties of L-asparagine monohydrate single crystal

This report presents investigation on influence of pH on growth, structural, thermal, linear and nonlinear optical properties of L-asparagine monohydrate (LAM) single crystal for the first time. Single crystals of LAM were grown at different pH by solution growth method by allowing slow evaporation of solvent. Crystal grown at pH 6.4 grows slowly as compare to other crystals grown at other pH values. The slight variation in lattice parameters of grown crystals has been confirmed by powder X-ray diffraction study. FT-IR study confirms the presence of functional groups of LAM in all grown crystals. Influence of pH on optical quality of crystals has been discussed. The crystal grown at pH 5.4 has maximum optical transparency and shows 2 and 20 % more transmission than crystals grown at pH 4.4 and 6.4, respectively. Other optical parameters like cutoff wavelength (λmax), band gap (Eg), linear refractive index (n), reflectance, extinction coefficient (k), electrical susceptibility (χ), optical conductivity(σop), electrical conductivity (σel) and Urbach energy (Eu) of all crystals have been evaluated from transmission data. The LAM crystal grown at pH 6.4 show high values of third order nonlinear optical parameters, as compare to other grown crystals, that attest its suitability for applications like higher harmonic generation, optical switching, optical limiting and other photonic applications over other grown crystals. Thermal stability of the grown crystals has been attested by TG-DTA study.

Intramolecular Charge Transfer and Stimuli-Responsive Emission in Cholesterol-Appended Phenothiazine-Cyanostyryl-Based Donor-Acceptor Systems.

Organic fluorescent molecules have received considerable attention owing to their various optoelectronic applications. Herein, we report the design and synthesis of two cholesterol-functionalized cyanostyrene-phenothiazine-based D-π-A systems that are emissive in both the solution and solid states. The newly synthesized cholesterol-appended phenothiazine-cyanostyrene diads PTCS-1 and PTCS-2 vary in the N-alkylation of phenothiazine, respectively, with─octyl and─hexyl chains. Both molecules are highly fluorescent and show reasonably good quantum yields in nonpolar solvents because of twisted intramolecular charge transfer (TICT). The molecules exhibit aggregation-induced emission in the solid state. Due to the presence of flexible alkyl chains in the phenothiazine and cholesterol moieties, PTCS-1 and PTCS-2 show mechanochromic luminescence switching in response to external shear stress and emission recovery under methanol vapor. Powder X-ray diffraction studies prove that the emission switching on the applied stimuli in both PTCS-1 and PTCS-2 is attributed to the reversible transformation between the crystalline and amorphous states. Time-dependent density functional theory (TD-DFT) studies are carried out to gain insight into the ICT interactions. TD-DFT analysis at the TD-M06-2X/def2-TZVP level further revealed that in both molecules, the lowest unoccupied molecular orbital (LUMO) + 2, LUMO, highest occupied molecular orbital (HOMO), and HOMO - 1 orbitals are responsible for the charge transfer interactions. These ICT interactions are identified as π-π* type interactions.

Effect of Polymorphism on the Sorption Properties of a Flexible Square-Lattice Topology Coordination Network.

The stimulus-responsive behavior of coordination networks (CNs), which switch between closed (nonporous) and open (porous) phases, is of interest because of its potential utility in gas storage and separation. Herein, we report two polymorphs of a new square-lattice (sql) topology CN, X-sql-1-Cu, of formula [Cu(Imibz)2]n (HImibz = {[4-(1H-imidazol-1-yl)phenylimino]methyl}benzoic acid), isolated from the as-synthesized CN X-sql-1-Cu-(MeOH)2·2MeOH, which subsequently transformed to a narrow pore solvate, X-sql-1-Cu-A·MeOH, upon mild activation (drying in air or heating at 333 K under nitrogen). X-sql-1-Cu-A·MeOH contains MeOH in cavities, which was removed through exposure to vacuum for 2 h, yielding the nonporous (closed) phase X-sql-1-Cu-A. In contrast, a more dense polymorph, X-sql-1-Cu-B, was obtained by exposing X-sql-1-Cu-(MeOH)2·2MeOH directly to vacuum for 2 h. Gas sorption studies conducted on X-sql-1-Cu-A and X-sql-1-Cu-B revealed different switching behaviors to two open phases (X-sql-1-Cu·CO2 and X-sql-1-Cu·C2H2), with different gate-opening threshold pressures for CO2 at 195 K and C2H2 at 278 K. Coincident CO2 sorption and in situ powder X-ray diffraction studies at 195 K revealed that X-sql-1-Cu-A transformed to X-sql-1-Cu-B after the first sorption cycle and that the CO2-induced switching transformation was thereafter reversible. The results presented herein provide insights into the relationship between two polymorphs of a CN and the effect of polymorphism upon gas sorption properties. To the best of our knowledge, whereas sql networks such as X-sql-1-Cu are widely studied in terms of their structural and sorption properties, this study represents only the second example of an in-depth study of the sorption properties of polymorphic sql networks.

Fabrication, characterization and application of W/N co-doped zinc oxide nanoparticles as a promising photoanode for dye-sensitized solar cells

In the present investigation, undoped, W doped, and W/N co-doped ZnO nanoparticles were prepared by sol–gel route. Here, the ZnO layers were fabricated via the doctor blade method. Hexagonal wurtzite structure is determined by XRD studies. The formation of a hexagonal wurtzite structure was observed from X-ray powder diffraction (XRD) resulting in a slight increase in crystallite size with an increase in doping content. The UV observation shows that W/N co-doping shifted the absorption spectra towards a higher wavelength and reduces the band gap energy. The EDS spectra confirms the high purity and triumphant doping of the W(tungsten) and N(nitrogen) into the ZnO lattice. The morphology of undoped and W/N co-doped ZnO nanoparticles was demonstrated by using FESEM and HRTEM. The 2 % W and 1.5 % N co-doped ZnO photoanode based DSSC (dye-sensitized solar cells) gained the highest short circuit current density of 8.44 mAcm−2 having an open-circuit voltage of 0.65 V, and PCE (power conversion efficiency) of 3.60 %.

Application of ultrasound-assisted compression and 3D-printing semi-solid extrusion techniques to the development of sustained-release drug delivery systems based on a novel biodegradable aliphatic copolyester

The purpose of this study was to investigate the ability of two advanced hot-processing technologies, Ultrasound-Assisted Compression (USAC) and 3D-printing Semi-solid Extrusion (SSE), to manufacture sustained-release drug delivery systems based on a novel biodegradable aliphatic copolyester. The copolymer was synthesized from ω-pentadecalactone (PDL), 1,4-cyclohexanedimethanol (CHDM) and dimethyl succinate (DMS) (monomer ratio PDL/CHDM/DMS 70/30/30) by enzymatic ring opening polymerization and two-step melt polycondensation processes and has a random microstructure, a high molecular weight (107,100 g mol−1) and a relatively low melting point (∼65 °C). The antibacterial agent metronidazole (MTZ) was chosen as model drug and binary physical mixtures copolymer:drug were prepared at 90:10 and 70:30 w/w ratios. Thermal analysis studies evidenced that the formulations could be processed below their degradation temperatures. Drug delivery devices with dense and meshed structures were manufactured using USAC and SSE techniques, respectively, with USAC devices exhibiting more reproducible physical properties than the SSE systems. Powder X-ray diffraction and scanning electron microscopy studies showed a partial sintering of the copolyester during USAC processing while MTZ remained mostly crystalline. In contrast, the copolymer melted and the drug underwent some amorphization when processed using SSE. In vitro drug release studies in phosphate buffer (pH 6.8) showed that, after an initial burst release of metronidazole, USAC and SSE devices exhibited a prolonged and/or sustained drug release over 20 days. The initial burst release was dependent on the manufacturing technique and the drug/polymer ratio, being minimized for SSE devices containing 10 wt% MTZ. The whole drug release profiles fitted well to the Peppas-Sahlin model, being drug diffusion the predominant release mechanism. After the burst release, the sustained release period of USAC and SSE devices containing 10 wt% MTZ showed a good fit to the zero-order kinetic model, with faster drug release from the SSE devices due to the larger surface area of their meshed structure. In conclusion, this work demonstrates that processing the aliphatic copolyester by both USAC and SSE technologies provides an attractive strategy to manufacture biodegradable drug delivery systems for long-term release of metronidazole.

Structure, Self-Assembly, and Phase Behavior of Neuroactive N-Acyl GABAs: Doxorubicin Encapsulation in NPGABA/DPPC Liposomes and Release Studies.

N-Acylated amino acids and neurotransmitters in mammals exert significant biological effects on the nervous system, immune responses, and vasculature. N-Acyl derivatives of γ-aminobutyric acid (N-acyl GABA), which belong to both classes mentioned above, are prominent among them. In this work, a homologous series of N-acyl GABAs bearing saturated N-acyl chains (C8-C18) have been synthesized and characterized with respect to self-assembly, thermotropic phase behavior, and supramolecular organization. Differential scanning calorimetric studies revealed that the transition enthalpies and entropies of N-acyl GABAs are linearly dependent on the acyl chain length. The crystal structure of N-tridecanoyl GABA showed that the molecules are packed in bilayers with the acyl chains aligned parallel to the bilayer normal and that the carboxyl groups from opposite layers associate to form dimeric structures involving strong O-H···O hydrogen bonds. In addition, N-H···O and C-H···O hydrogen bonds between amide moieties of adjacent molecules within each layer stabilize the molecular packing. Powder X-ray diffraction studies showed odd-even alternation in the d spacings, suggesting that the odd chain and even chain compounds pack differently. Equimolar mixtures of N-palmitoyl GABA and dipalmitoylphosphatidylcholine (DPPC) were found to form stable unilamellar vesicles with diameters of ∼300-340 nm, which could encapsulate doxorubicin, an anticancer drug, with higher efficiency and better release characteristics than DPPC liposomes at physiologically relevant pH. These liposomes exhibit faster release of doxorubicin at acidic pH (<7.0), indicating their potential utility as drug carriers in cancer chemotherapy.

Oral pH triggered colon-specific ketoprofen loaded microspheres for the better management of early morning symptoms associated with rheumatoid arthritis. Part I: Optimization, in-vitro, and ex-vivo characterization

The primary goal of this research was to investigate pH-triggered colon-specific ketoprofen-loaded microspheres (C-SKLM) using Eudragit S-100 as a pH-dependent polymer. The formulation was optimized using the Box-Behnken design. The suggested C-SKLM formulation with the amount of ketoprofen = 189.09 mg, the amount of Eudragit-100 = 600 mg, and the paddle speed = 400 rpm showed a considerable particle size (106 µm), drug encapsulation efficacy (79.67%), and % cumulative drug release at 5th hr (8.62) and 10th hr (92.62) for oral administration. Microphotographs of scanning electron microscopy indicated that the optimized C-SKLM was smooth and spherical. The differential scanning calorimetry and X-ray powder diffraction studies have shown that ketoprofen was dispersed in the polymer in its optimized C-SKLM formulation, and the spectra from the Fourier transform infrared study have shown no significant drug-polymer interaction. Ex-vivo permeation studies on isolated rat gastro-intestinal segments revealed that the maximum amount of ketoprofen permeated after 2 h through the isolated stomach (0.559 ± 0.049 mg), small intestine (1.36 ± 0.226 mg), and colon (0.972 ± 0.068 mg) was observed for ketoprofen pure. In contrast, a significantly lesser amount of the drug was permeated through the stomach (0.1 ± 0.025 mg) and small intestine (0.28 ± 0.1 mg) than the colon (0.697 ± 0.23 mg) from the ketoprofen-loaded microspheres formulation. In-vitro and ex-vivo permeation studies suggest that the developed C-SKLM could be helpful for the effective management of early morning symptoms due to rheumatoid arthritis by delaying the release by targeting the colon.

Highly Efficient Non-Enzymatic Electrochemical Glucose Biosensor Based on Copper Metal Organic Framework Coated on Graphite Sheet

Detection of glucose is highly informative, creating a constant demand for fabricating high-precision glucose biosensors. Metal–organic frameworks, a family of porous materials renowned for their tunability, can be an excellent choice for developing such sensors. We have developed a highly-sensitive, non-enzymatic sensor for electrochemical detection of glucose fabricated using Copper Metal–Organic Framework (Cu MOF), synthesized by a simple, room-temperature stirring method using Benzene-1,3,5-tricarboxylic acid (BTC) as ligand and Copper nitrate trihydrate as precursor. The synthesized nanostructure was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analytical techniques. Powder X-ray diffraction study and thermogravimetric analysis were also done. Further, Brunnauer-Emmett-Teller analysis revealed the porous nature of Cu MOF. The materials exhibited strong electro-catalytic activity for glucose oxidation as revealed from cyclic voltammetry and chronoamperometric studies done under alkaline pH conditions. The Cu MOF deposited on a conducting graphite sheet electrode displayed a significantly low detection limit of 0.019 mM through a broad detection range (1–15 mM) and a strong sensitivity of 229.4 μAmM−1 cm2. Overall, the Cu MOF/GS exhibits exceptional stability, short response time (less than 1 s), and good repeatability and reproducibility, making it a promising future material for non-enzymatic glucose detection.

Synthesis, structural elucidation and characterization of a new organic single crystal Guanidinium adipate monohydrate (GuAM) for nonlinear optical applications

A slow evaporation solution growth process was employed to grow a new organic single crystal Guanidinium adipate monohydrate (GuAM) at room temperature. The structure refinement and cell specifications were elucidated using the X-ray diffraction method. Single crystal XRD study revealed that the grown crystal crystallized in the monoclinic system with unit cell dimensions a = 4.948 (9) Å; b = 16.770 (2) Å; c = 13.554 (2) Å; α and γ = 90.00⁰; β = 95.302⁰ (3), V = 1120.1(3) Å3 and Z = 4. The structure of the crystal was solved by direct method and refined by full matrix least-square method using SHELXL-2018/3 program. The crystalline nature of the sample was evaluated by powder X-ray diffraction (PXRD) study. Fourier transform infrared (FTIR) spectral study was employed to recognize the diverse functional groups present in the synthesized crystal. Optical attributes such as absorbance and emission nature of the GuAM were explored using UV–visible-NIR absorbance study and photoluminescence study respectively. The laser damage threshold value of the formed crystal has been determined by employing an Nd-YAG laser with a wavelength of 1064 nm. The mechanical nature of the GuAM was examined utilizing Vicker's microhardness test and other related parameters were also calculated. TGA-DTA analysis was utilized to estimate the title crystal's thermal stability. The Z-scan technique has been employed to gain insight into the third order nonlinear (NLO) parameters of the GuAM. These findings imply that guanidinium adipate monohydrate (GuAM), a grown single crystal, may be a viable choice for NLO applications.

Influence of annealing temperature on microstructure, magnetic and electrical properties of Ce doped cobalt ferrite nanoparticles

Cerium doped cobalt ferrite nanoparticles with chemical formula CoFe1·9Ce0·1O4 were synthesized at different annealing temperatures (600, 700, 800, 900 and 1000C°) via sol-gel auto-combustion method. Thermal analysis for sample annealed at 1000C° was examined through differential scanning calorimetry (DSC) and revealed the presence of exothermic peak at around 500C° attributed to crystallization of prepared nanoferrites. Structural analysis such as phase formation, crystallinity and morphology was investigated by x-ray powder diffraction (XRD) and high resolution transmission electron microscope (HRTEM). XRD study revealed higher dependence of grain size growth with annealing temperatures as compared to lattice parameter. HRTEM investigation confirmed that grains have almost uniform morphology with some agglomeration and confirmed values of lattice parameters and grain sizes calculated from XRD data. Magnetic hysteresis was studied by vibrating sample magnetometer (VSM) at room temperature with an applied field of 20 kOe. The results showed an increase in saturation magnetization and remanent magnetization with increasing of annealing temperature, whereas a decline in coercivity was observed. Distribution of cations at tetrahedral and octahedral sites was investigated using x-ray and magnetic parameters which confirmed the mixed spinel ferrite nature of samples. Dielectric properties were carried out at room temperature in the range 0.1Hz–3.0 MHz. Both dielectric constant and ac conductivity decreased with rising of annealing temperature. Variation of dielectric loss tangent, impedance, electric modulus and relaxation time with temperature were also investigated. The effect of annealing temperature on the structure and its impact on magnetic and dielectric properties has been examined and discussed.