Hexagonal Phase Structure Research Articles

Structural, thermal and light emission properties of Eu, Sm, Dy, Er and Mn doped CaAl2O4 and SrAl2O4

1 mol% Re2O3/MnO – 99 mol% MAl2O4 (Re = Eu, Sm, Dy, Er and M = Ca and Sr) powder samples were prepared by solid state sintering in the temperature range of 1386–1450 °C and their structural, thermal and photoluminescence properties were compared. X-ray diffraction and Rietveld refinement studies of calcium aluminate samples confirm the formation of monoclinic CaAl2O4 along with a small concentration (1.9–4.6 wt %) of monoclinic CaAl4O7 while the strontium aluminate samples contain monoclinic SrAl2O4 and a small amount (0.7–3.5 wt %) of cubic Sr3Al2O6. The short-range structure of CaAl2O4 consists of CaO6, CaO9 and AlO4 structural units while that of SrAl2O4 contains SrO9 and AlO4 units. The Sr–O bond-lengths (2.32–3.58 Å) are longer than Ca–O bond-lengths (2.04–3.18 Å) and Al–O bond-lengths are of the range 1.35–2.12 Å. Differential scanning calorimetry studies reveal high thermal stability of calcium aluminates, while strontium aluminate samples show reversible monoclinic to - hexagonal structural phase transition at 688 °C during heating cycle. Raman spectra exhibit Al–O vibrational modes. Photoluminescence studies show reddish-orange emission in Eu, Sm and Mn-doped samples, Er doped samples show green emission and Dy-doped samples emit yellow-white light. Calcium aluminate samples show significantly higher luminescence intensity and quantum yield than strontium aluminates.

NiRu0.3Se Nanoparticles In Situ Grown on Reduced Graphene: Synthesis and Electrocatalytic Activity in the Oxygen Evolution Reaction

AbstractNanoscale transition metal selenides have been tagged as promising electrocatalytic materials for efficient energy conversion. Herein, we report the facile hydrothermal synthesis of NiRu0.3Se nanoparticles, in situ grown on reduced graphene oxide, for oxygen evolution reaction (OER) in water splitting. The crystal phase, morphology and elemental composition of NiRu0.3Se/rGO is well characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS) and energy dispersive X‐ray spectroscopy (EDX). The composite exhibited hexagonal and cubic phase structure corresponding to NiSe and RuSe2, having irregular morphology. NiRu0.3Se/rGO exhibited superior OER performance than NiSe/rGO requiring an overpotential of 290 mV to generate a benchmarked current density of 10 mA cm−2 in 0.1 M KOH. A small tafel slope of 98 mV dec−1 and long‐term stability endorses the potential of NiRu0.3Se/rGO as an efficient OER electrocatalyst.

The crystal structures and magnetic properties of TiFeSi coexisting in hexagonal and orthorhombic symmetries

The intertwisted helix framework of the chiral FeSi-type structure with the space group P213 (S.G. P213) inspired us to investigate other non-centrosymmetric compounds, particularly 111-type phases with different FeSi frameworks. Various FeSi-containing 111-type phases have been summarized according to their valence electron counts and space group. In this work we have focused on the non-centrosymmetric TiFeSi phase. The crystal structure analysis of the hexagonal Fe2P-type and the reported orthorhombic TiFeSi-type (α-TiFeSi) indicate a superlattice relationship exists between the two structures, which drove us to perform the total energy calculations of the hexagonal and orthorhombic models of TiFeSi. Following the theoretical predictions, a hexagonal TiFeSi phase (β-TiFeSi) is proposed and successfully synthesized at high temperature using arc melting. The crystal structure of the high-temperature hexagonal phase was determined by powder and single crystal X-ray diffraction. After the annealing of the arc-melted samples, TiFeSi crystallizes into an orthorhombic structure with the space group Ima2. The systematic magnetic characterizations indicate ferromagnetic properties are present in the non-centrosymmetric orthorhombic α-TiFeSi phase with possible helical magnetic ordering at low temperatures. Moreover, to compare with the centrosymmetric cases, the electronic and magnetic properties of the antiferromagnetic TiNiSi-type MFeSi (M = Zr and Hf) compounds were also examined using both density functional theory and experimental magnetic measurements.

Green synthesis of ZnO nanoparticles for antimicrobial and vegetative growth applications: A novel approach for advancing efficient high quality health care to human wellbeing

The present work aims to synthesize zinc oxide (ZnO) nanoparticles via green approaches using leaf extract of Parthenium hysterophorus. UV–vis and FT-IR tests confirmed the existence of biomolecules, active materials, and metal oxides. The X-ray diffraction structural study exposes the ZnO nanoparticles formation with hexagonal phase structures. SEM and TEM analysis reveal surface morphologies of ZnO nanoparticles and most of them are spherical with a size range of 10 nm. ZnO nanoparticles were revealed strong antimicrobial activity against both bacterial and fungal strains. The germination of seeds and vegetative growth of Sesamum indicum has been greatly improved.

Different morphologies of WO3 and their exposed facets-dependent acetone sensing properties

Daisy-like hexagonal WO3 and rose-like monoclinic WO3 hierarchical structures were fabricated via facile hydrothermal technic in this work. The acetone sensing properties of the products were evaluated in detail. The results reveal that the hexagonal daisy-like WO3 sensor exhibits high sensitivity, good selectivity, rapid response/recovery, and remarkable repeatability to acetone (0.2∼200 ppm) at 260 °C. The outstanding sensing performance is attributed to the synergistic effects of the dominant (002) facets and the intracrystalline tunnel structure of hexagonal phase. The morphology formation mechanism and the acetone sensing mechanism are discussed. This work has practical significance for environmental monitoring of acetone as well as for breath diagnosis of diabetes.

Preparation, structure and microwave dielectric properties of novel La2MgGeO6 ceramics with hexagonal structure and adjustment of its τf value

A novel La2MgGeO6 ceramic was synthesized through a solid-state reaction process within a sintering temperature range of 1450–1550 °C. By a combination of X-ray diffraction and Rietveld refinement analyses, the ceramics were found to have a pure hexagonal phase structure belonging to space group R3/146. The scanning electron microscopy images revealed that the ceramic grains were closely connected. The effects of internal (lattice energy, valence bond, and fraction packing) and external factors (density) on the microwave properties of ceramics were also studied. The ceramic exhibited excellent microwave dielectric performances, with a relative permittivity (Ɛr) of 21.2, a quality factor (Q × f) of 52 360 GHz, and a temperature coefficient of resonant frequency (τf) of −44.2 ppm/°C, when sintered at 1500 °C for 4 h. The τf value of the La2MgGeO6 ceramic doped with CaTiO3 could be adjusted to zero. Particularly, 0.2La2MgGeO6-0.8CaTiO3 ceramics have good microwave dielectric properties with τf = +2.1 ppm/°C, Q × f = 15 610 GHz, and Ɛr = 40.3.

Effects of deformation and annealing on the microstructures and properties of a nonequiatomic Co29Cr29Fe29Ni12.5W0.5 high-entropy alloy

Nonequiatomic Co 29 Cr 29 Fe 29 Ni 12.5 W 0.5 high-entropy alloys (HEAs) were prepared by vacuum induction melting and subsequent mechanical processing. The HEA with face-centered cubic and few hexagonal close-packed structure phases exhibited outstanding mechanical properties. After annealing at 725 °C, the yield strength and fracture elongation were 1.13 GPa and 24.3%, respectively. The outstanding mechanical properties were attributed to the addition of the W element and ultrafine grain structure. The results demonstrated that dislocation slip, stacking faults, and nano-twins governed the deformation mechanism, and these defects were responsible for the decrease in the work-hardening rate during the deformation processing in the 725°C-annealed alloy.

Structure of (ZrTi)0.5(VCrFe(Ni0.9Cu0.1))0.5- and (ZrTi)0.5(VMoFeNi)0.5-Based Deuterides

We have synthesized (ZrTi)0.5(VCrFe(Ni0.9Cu0.1))0.5 and (ZrTi)0.5(VMoFeNi)0.5 pseudobinary high-entropy compounds and related deuterides. According to neutron and X-ray diffraction results, the deuterides have the same hexagonal Laves phase structure as the parent alloys. We have determined the position of the deuterium atoms and their atomic position coordinates. The results indicate that the deuterium atoms reside predominantly in positions 24l and 12k2, typical of hydrogen in hexagonal Laves phases.

Crotalaria verrucosa Leaf Extract Mediated Synthesis of Zinc Oxide Nanoparticles: Assessment of Antimicrobial and Anticancer Activity.

In this work, we present an ecofriendly, non-hazardous, green synthesis of zinc oxide nanoparticles (ZnO NPs) by leaf extract of Crotalaria verrucosa (C. verrucosa). Total phenolic content, total flavonoid and total protein contents of C. verrucosa were determined. Further, synthesized ZnO NPs was characterized by UV–visible spectroscopy (UV-vis), X-ray diffractometer (XRD), Fourier transform infra-red (FTIR) Spectra, transmission electron microscope (TEM), and Dynamic light scattering (DLS) analysis. UV-vis shows peak at 375 nm which is unique to ZnO NPs. XRD analysis demonstrates the hexagonal phase structures of ZnO NPs. FTIR spectra demonstrates the molecules and bondings associated with the synthesized ZnO NPs and assures the role of phytochemical compounds of C. verrucosa in reduction and capping of ZnO NPs. TEM image exhibits that the prepared ZnO NPs is hexagonal shaped and in size ranged between 16 to 38 nm which is confirmed by DLS. Thermo-gravimetric analysis (TGA) was performed to determine the thermal stability of biosynthesized nanoparticles during calcination. The prepared ZnO NPs showed significant antibacterial potentiality against Gram-positive (S. aureus) and Gram-negative (Proteus vulgaris, Klebsiella pneumoniae, and Escherichia coli) pathogenic bacteria and SEM image shows the generalized mechanism of action in bacterial cell after NPs internalization. In addition, NPs are also found to be effective against the studied cancer cell lines for which cytotoxicity was assessed using MTT assay and results demonstrate highest growth of inhibition at the concentration of 100 µg/mL with IC50 value at 7.07 µg/mL for HeLa and 6.30 µg/mL for DU145 cell lines, in contrast to positive control (C. verrucosa leaf extract) with IC50 of 22.30 µg/mL on HeLa cells and 15.72 µg/mL on DU145 cells. Also, DAPI staining was performed in order to determine the effect on nuclear material due to ZnO NPs treatment in the studied cell lines taking leaf extract as positive control and untreated negative control for comparison. Cell migration assay was evaluated to determine the direct influence of NPs on metastasis that is potential suppression capacity of NPs to tumor cell migration. Outcome of the synthesized ZnO NPs using C. verrucosa shows antimicrobial activity against studied microbes, also cytotoxicity, apoptotic mediated DNA damage and antiproliferative potentiality in the studied carcinoma cells and hence, can be further used in biomedical, pharmaceutical and food processing industries as an effective antimicrobial and anti-cancerous agent.

Facile synthesis of NiO@Ni(OH)2-α-MoO3 nanocomposite for enhanced solid-state symmetric supercapacitor application

Electrochemical supercapacitor fabrication using heterogeneous nanocomposite is one of the most promising pathways for energy storage technology. Herein, heterostructure based nickel-molybdenum (NiO@Ni(OH)2-α-MoO3) nanocomposites have been successfully prepared on nickel foil via hydrothermal route for supercapacitor application. The mixed phases of cubic, hexagonal, and orthorhombic crystal structure for NiO, Ni(OH)2, and α-MoO3, respectively were observed by X-ray diffraction. Heterostructures of nanosheet and nanosphere morphologies were confirmed by high resolution transmission electron microscopy. Impressively, the NiO@Ni(OH)2-α-MoO3 composite working electrode exhibits a high specific capacitance of 445 Fg−1 at current density of 1 Ag−1 and shows outstanding rate capability (97.3% capacity retention after 3000 cycles at 10 Ag−1), compared to that of NiO@Ni(OH)2 nanoparticles. Notably, two-electrode symmetric supercapacitor of NiO@Ni(OH)2-α-MoO3 working electrode shows a high specific capacitance of 172 Fg−1 at 0.5 Ag−1, excellent rate capability and good cycling stability. Also, an excellent cycling stability (capacity retention of 98% after 5000 cycles) is observed for NiO@Ni(OH)2-α-MoO3 as a working electrode in the symmetric two-electrode system. The obtained attractive results demonstrate that nanocomposite anode material can be used for development of a wide-range of energy storage devices.

Enhanced antibacterial activity of Ag-doped ZnS nanoparticles synthesised by a microwave-assisted polyol method

ABSTRACT Silver doped zinc sulphide nanoparticles were synthesised by a microwave-assisted polyol method. Characterisation of nanoparticles was performed using XRD, FESEM-EDXand UV-visible spectroscopy to investigate chemical structure, crystalline phase, particle size and surface morphology. Antibacterial properties of synthesised nanoparticles were investigated by determining their MIC and MBC values and kinetic of bactericidal activity against Staphylococcus aureus(ATCC 6538) and Escherichia coli(ATCC 25922). Characterisation of the synthesised nanoparticles showed formation of single phase of hexagonal wurtzite ZnS structure with Ag+ substitution at 1.6% Zn/Ag molar ratio. MIC values were determined as 250 and 500 µg/ml against Staphylococcus aureus and Escherichia coli, respectively and time kill profiles showed efficient and rapid bactericidal activity of the synthesised Ag-doped ZnS nanoparticles. Results of this study suggest a synthesis strategy for Ag-doped ZnS nanoparticles with potent and broad spectrum antibacterial properties that can widen the range of applications of these nanoparticles.

INFLUENCE OF NICKEL DOPING CONCENTRATION ON THE CHARACTERISTICS OF NANOSTRUCTURE CuS PREPARED BY HYDROTHERMAL METHOD FOR ANTIBACTERIAL ACTIVITY

Pure and nickel doped copper sulfide (CuS) nanostructure were prepared by hydrothermal method for 5 h at [Formula: see text]C. Structural, morphological and optical properties of the CuS nanostructure were studied for different Ni-doping concentration of 1%, 2%, 3%, 4%, and 5 %. X-ray diffraction studies showed the polycrystalline nature with hexagonal phase structure of CuS and Ni: CuS nanostructure. FE-SEM image showed that nickel doping concentration affected the nanostructure morphology. The absorbance spectra were then recorded at wavelengths ranging from 350 nm to 1000 nm, where the CuS nanostructures have strong absorbance in the NIR. The optical band gap energy of the samples increased as nickel concentration increasing. In particular, their optical band gap energies were 3.25, 3.48, 3.49, 3.49, 3.45 and 3.44 eV for undoped and Ni-doped CuS nanostructure with concentrations (1%, 2%, 3%, 4% and 5%), respectively. The antibacterial activity of Copper sulfide nanostructure against P. aeruginosa, E. coli, and S. aureus was evaluated by zone of inhibition. The test revealed that copper sulfide nanostructure have a strong antibacterial activity against gram-positive than for gram-negative with low concentration of CuS.

Structural features of solid-solid phase transitions and lattice dynamics in U3O8

Triuranium octoxide $({\mathrm{U}}_{3}{\mathrm{O}}_{8})$ undergoes an orthorhombic to hexagonal structural phase transition near ${T}_{s}=305{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$, and a separate nonstructural phase transition at ${T}_{c}=210{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. The later transition has previously been associated with temperature-induced fluctuations in the uranium oxidation state. A discontinuity in the slope of electrical conductivity versus temperature measurement at $210{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ has supported this idea. The orthorhombic phase has three crystallographic sites in two distinct oxidation configurations [2 U(V) and 1 U(VI)], whereas the hexagonal phase has one distinct uranium site. High-resolution x-ray diffraction measurements eliminate the possibility of superlattice Bragg reflections to less than 0.2 ${\mathrm{e}}^{\ensuremath{-}}$ scattering power and ${\mathrm{U}}_{3}{\mathrm{O}}_{8}$ is not metallic; consequently, the presence of oxidation fluctuations is required for charge balancing. Interestingly, the order-to-disorder transition occurs at a much lower temperature than the structural transition. Using temperature-dependent x-ray diffraction and Raman spectroscopy, we show anisotropic lattice expansion in the in-plane $b$ and $c$ lattice constants. A specific discontinuity in the temperature derivatives of the $b$ and $c$ lattice constants are the first reported structural signatures of the order-to-disorder transition, suggestive of a change in local U--O coordination. Phonon frequencies of ${\mathrm{U}}_{3}{\mathrm{O}}_{8}$ measured by Raman spectroscopy show significant temperature-dependent dynamics. Redshifting of several modes between 40 and $300{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ cannot be explained by unit cell expansion alone because the unit cell volume decreases in this region. Instead, we show that phonon frequencies are highly correlated with the anisotropic lattice expansion/contraction along specific crystallographic directions.

Microstructure evolution in U-10Zr alloy irradiated by swift Xe ions at 700 ∘C

The post-irradiation examination (PIE) results of U-10Zr binary metallic fuel that was irradiated by 84 MeV Xe ions at 700 ∘C are reported. The U-10Zr specimen was synthesized by homogenizing elemental U and Zr powders through arc-melting. The as-fabricated U-10Zr was dominated by the sub-micron acicular α+δ phase. After being irradiated by 84 MeV Xe ions at 700 ∘C up to 2.19 × 1017 ions/cm2 fluence, the U-10Zr was speculated to evolve into micro-scale γ1+γ2 phases as predicted by the U-Zr phase diagram. During post-irradiation cooling, the U-rich γ1 phase was mainly transformed to the α phase, while the Zr-rich γ2 phase was partially retained along with formation of hexagonal structure phase (δ or ω). Xe bubbles formed in the γ1 and γ2 phases have salient different morphologies, implying faster Xe diffusion in the γ1 phase than the γ2 phase. The quantitative bubble morphology data collected in this study can provide valuable references for the development and validation of fuel performance models for this fuel.

Citrate sol-gel synthesis of BaAl2O4:x% Cu2+ (0 ≤ x ≤ 1) nano-phosphors: Structural, morphological and photoluminescence properties

Abstract This paper reports on the effects of varying the Cu2+ doping concentration on the structure, morphology and optical properties of the BaAl2O4 phosphor. BaAl2O4:x% Cu2+ (0 ≤ x ≤ 1) series were successfully synthesized via citrate sol-gel method. The X-ray diffraction (XRD) results revealed that the prepared phosphor sample consist of a single phase hexagonal structure. The presence of Ba, Al, O and Cu were confirmed by the energy dispersive X-ray spectroscopy (EDS). Scanning electron microscope (SEM) revealed that the morphology of the prepared samples highly depends on the Cu2+ concentration. Transmission electron microscopy (TEM) results revealed the hollow tubular and nano-nature of the crystallite sizes. When the un-doped sample was excited at 283 nm, the photoluminescence (PL) results revealed six emission peaks located at 420, 435, 457, 521, 612 and 722 nm, which were attributed to the intrinsic intra band gap defects within the BaAl2O4 (host). The emission at 425 nm observed for the BaAl2O4:Cu2+ samples was attributed to the 3d84s1 → 3d9 transition in Cu2+ ion. The optimum doping Cu2+ concentration was found to be 0.075% Cu2+. Critical energy transfer distance (Rc) of Cu2+ ions was found to be 12.01 A, which suggested that the multipole-multipole interaction was the main reason for the luminescence quenching. The International Commission on Illumination (CIE) colour showed that the bluish emission colour of the prepared samples depends on the excitation wavelength and Cu2+ concentration. Thermo stimulated luminescence (TSL) of the host material showed the presence of both the swallow and deep traps respectively located at 75 and 240 °C.

Effects of CdS Nanoparticles on the Physical Properties of T-CdS Nanocomposite Materials

In this work, has been studied the effects of CdS nanoparticles at different concentrations on the microstructure and optical properties of TiO2/CdS nanocomposites (T-CdS). The structural properties of T-CdS samples were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM). XRD analysis confirms the hexagonal wurtzite phase structure of CdS nanoparticles and the tetragonal anatase phase of TiO2 nanoparticles. TEM images appear the shapes and sizes of TiO2, CdS nanoparticles and T-CdS nanocomposite, where found in aggregates nanoparticles their sizes from 15 to 56 nm. By UV–vis diffuse reflectance spectrum (DRS) were determined Band-gap energies of the samples. The Photoluminescence (PL) analysis exposed, with the excitation wavelength of 285 nm, our samples exhibited the intensity of peak at 426 nm. Additionally, the FTIR spectroscopy of the samples exhibits‎ the presence of functional groups. The thermal stability of T-CdS nanocomposite samples were determined by thermogravimetric and differential thermal analysis.

Solution-processable zinc oxide based thin films with different aluminum doping concentrations

Al doped zinc oxide (AZO) thin films are attempted to be formed on glass substrates via solution processing with 0, 0.5, 1, 2, 3, and 4 at% Al doping concentrations. Analysis of X-ray diffraction patterns and scanning electron microscopy micrographs indicate that the AZO thin films belong to the wurtzite hexagonal structure with (100), (002), (101), (102), (110), (103), (112) and (201) orientations, and show that the grain size of AZO thin films decreases with higher Al doping concentrations. Optical and electrical properties of the AZO thin films are characterized from using a UV/vis spectrometer and a four-probe measurement system, respectively. The AZO thin films obtained have a minimum sheet resistance of 30.41 Ω/sq for the dopant concentration of 1 at%, and a bandgap energy varying from 3.26 eV to 3.16 eV as the Al doping concentration increases from 0 to 4 at%. The maximum figure of merit value of 7.48 × 10 −3 (Ω/sq) −1 corresponds to the deposition of the AZO thin film with 2 at% Al doping. • Al doped ZnO thin films with a single phase of wurtzite hexagonal crystal structure successfully prepared. • Sheet resistivity approached to the lowest value with the doping concentration of 1 at%, which is comparable with other reports. • Maximum figure of merit corresponded to the AZO thin film with 2 at% Al doping.

Remarkable photocatalytic activity of Zr doped ZnO and ZrO2/ZnO nanocomposites: Structural, morphological and photoluminescence properties

Industrial effluents containing synthetic organic dyes impose a significant level of threatening to the environment and to the health of living organisms. In the context to develop active materials able to degrade synthetic textile dyes, we report highly efficient photocatalysts composed of Zr doped ZnO and ZrO2/ZnO heterostructures synthesized via modified sol-gel Pechini method. The crystal structure, morphology and the optical properties of the synthesized powders were characterized using XRD, Rietveld refinement, SEM, EDX and diffuse reflectance. A single phase of ZnO hexagonal structure was found in pure and 5 wt% Zr doped ZnO, whereas multi-phases consist of hexagonal ZnO plus either tetragonal or monoclinic ZrO2 were detected using higher concentrations of Zr (10–50 wt %). Pure ZnO shows nanospherical-shaped particles with average size of 36 nm ZrO2/ZnO nanocomposites with ZrO2 content of 30, 40 and 50 wt% show similar spherical grains with homogeneous particle size distribution. EDX spectrum of ZrO2/ZnO nanocomposite confirms the existence of Zn, Zr and O elements and the absence of any impurities. ZrO2/ZnO nanocomposites exhibit two band gaps related to their individual components. The results of photocatalytic experiments revealed that both Zr doped ZnO and ZrO2/ZnO nanocomposites demonstrate remarkable photocatalytic activities for indigo carmine (IC) and methylene blue (MB) degradation. The highest degradation rate was realized by ZrO2/ZnO (50:50) nanocomposite with degradation efficiencies of 99% and 97% for IC and MB in 300 and 150 min, respectively. The superior activity of ZrO2/ZnO nanocomposite was attributed to the increases in the charge separation due to strong interfacial surface interaction. The fluorescence studies based on conversion of coumarin to 7-hydroxycoumarin showed similar results to the photocatalytic activity and proved the effective role of the hydroxyl radicals in the degradation process.

Photoluminescence and Magnetic Properties of Undoped and (Mn, Co) co-doped ZnO Nanoparticles

Objective: The influence of Manganese (Mn2+) and Cobalt (Co2+) ions doping on the optical and magnetic properties of ZnO nanoparticles was studied. Methods: Nanoparticle samples of type ZnO, Zn0.97Mn0.03O, Zn0.96Mn0.03Co0.01O, Zn0.95Mn0.03 Co0.02O, Zn0.93Mn0.03Co0.04O, and Zn0.91Mn0.03Co0.06O were synthesized using the wet chemical coprecipitation method. Results: X-ray powder diffraction (XRD) patterns revealed that the prepared samples exhibited a single phase of hexagonal wurtzite structure without any existence of secondary phases. Transmission electron microscope (TEM) images clarified that Co doping at high concentrations has the ability to alter the morphologies of the samples from spherical shaped nanoparticles (NPS) to nanorods (NRs) shaped particles. The different vibrational modes of the prepared samples were analyzed through Fourier transform infrared (FTIR) measurements. The optical characteristics and structural defects of the samples were studied through Photoluminescence (PL) spectroscopy. PL results clarified that Mn2+ and Co2+ doping quenched the recombination of electron-hole pairs and enhanced the number of point defects relative to the undoped ZnO sample. Magnetic measurements were carried out at room temperature using a vibrating sample magnetometer (VSM). (Mn, Co) co-doped ZnO samples exhibited a ferromagnetic behavior coupled with paramagnetic and weak diamagnetic contributions. Conclusion: Mn2+ and Co2+ doping enhanced the room temperature Ferromagnetic (RTFM) behavior of ZnO. In addition, the signature for antiferromagnetic ordering between the Co ions was revealed. Moreover, a strong correlation between the magnetic and optical behavior of the (Mn, Co) co-doped ZnO was analyzed.

Liquid crystalline nanodispersion functionalized with cell-penetrating peptides improves skin penetration and anti-inflammatory effect of lipoic acid after in vivo skin exposure to UVB radiation.

In this study, the development and the performance of a new targeted liquid crystalline nanodispersion (LCN) by the attachment of cell-penetrating peptides (CPP) onto their surfaces to improve skin delivery of lipoic acid (LA) were evaluated. For that, the synthesis and characterization of this new platform as well as its spatiotemporal analysis from in vitro and in vivo topical application were explored and extensively discussed in this paper. The TAT or D4 peptides were chosen as CPP due to specific target strategies by the charge grouping on the skin surface or target the overexpressed epidermal growth factor receptor (EGFR) of cell membrane of keratinocytes, respectively. Thus, the nanoparticle characterization results when taken together suggested that designed LCNs maintained their hexagonal phase structure, nanoscale particle size, and low polydispersity index even after drug, lipopolymers, and peptide additions, which are proved to be favorable for topical skin delivery. There were no statistical differences among the LCNs investigated, except for superficial charge of LCN conjugated with TAT which may have altered the LCN zeta potential due to cationic charge of TAT amino acid sequence compared with D4. The cumulative amounts of LA retained into the skin were determined to be even higher coming from the targeted LCNs. Moreover, the exogenous antioxidant application of the LA from the LCNs can prevent ROS damage, which was demonstrated by this study with the less myeloperoxidase (MPO) activity and decrease in cytokine levels (TNF-alpha and IL-1β) generated by the oxidative stress modulation. Together, the data presented highlights the potential of these targeted LCNs, and overall, opens new frontiers for preclinical trials.