Biomimetic Mineralized Fiber Bundle-Inspired Scaffolding Surface on Polyetheretherketone Implants Promotes Osseointegration

The stress shielding effect caused by traditional metal implants is circumvented by using polyetheretherketone (PEEK), due to its excellent mechanical properties; however, the biologically inert nature of PEEK limits its application. Endowing PEEK with biological activity to promote osseointegration would increase its applicability for bone replacement implants. A biomimetic study is performed, inspired by mineralized collagen fiber bundles that contact bone marrow mesenchymal stem cells (BMMSCs) on the native trabecular bone surface. The PEEK surface (P) is first sulfonated with sulfuric acid to form a porous network structure (sP). The surface is then encapsulated with amorphous hydroxyapatite (HA) by magnetron sputtering to form a biomimetic scaffold that resembles mineralized collagen fiber bundles (sPHA). Amorphous HA simulates the composition of osteogenic regions in vivo and exhibits strong biological activity. In vitro results show that more favorable cell adhesion and osteogenic differentiation can be attained with the novelsurface of sPHA than with SP. The results of in vivo experiments show that sPHA exhibits osteoinductive and osteoconductive activity and facilitates bone formation and osseointegration. Therefore, the surface modification strategy can significantly improve the biological activity of PEEK, facilitate effective osseointegration, and inspire further bionic modification of other inert polymers similar to PEEK.     

Synthesis of new dihybrid nanofluid of TiO2/MWCNT in water–ethylene glycol to improve mixture thermal performance: preparation,characterization, and a novel correlation via ANN based on orthogonal distance regression algorithm

Journal of Thermal Analysis and Calorimetry - Nanofluid refers to the mixture of fluid and solid nanoparticles. If this mixture contains more than one NP or fluid, it is called “hybrid...     

Photoinduced liquid crystal blue phase by bent-shaped cis isomer of the azobenzene doped in chiral nematic liquid crystal

A photoresponsive azobenzene molecule DCAZO2 with two cholesteryl groups linked to both sides of the azobenzene group is doped in a mixture of nematic liquid crystal E7 and chiral dopant S811 (61.9 wt% E7, 36.1 wt% S811 and 2.0 wt% DCAZO2). Cooled from isotropic phase to 33.0°C, chiral nematic liquid crystal (N*LC) was formed in the sample and then the temperature was kept unchanged at 33.0°C. UV light irradiation induces the trans–cis photoisomerisation and thus an obvious phase transition. When the azobenzene groups isomerise to a cis-saturated state, the UV light was turned off and the white light was turned on at the same time. The bent-shaped cis isomer then turns back to the planar trans isomer gradually. A blue–green platelet texture representing cubic blue phase (BP) was observed and the size of the platelets was increased along with the cis–trans isomerisation. UV–vis absorption spectra indicate that the photoinduced BP exists when the isomerisation degree is between 79% and 18%, and further cis–trans isomerisation change BP back into N*LC. The large geometric structure of the cholesteryl groups and the large bent angle θ of the cis isomer are supposed to be responsible for the interesting result.     

Designing Silicates as Deep-UV Nonlinear Optical (NLO) Materials using Edge-Sharing Tetrahedra

Discovering new deep-ultraviolet (DUV) nonlinear optical (NLO) materials is currently a great challenge. The reported DUV NLO materials are almost exclusively borates or phosphates. Silicates—the largest constituent of the earth's crust—are excluded owing to their weak second harmonic generation (SHG) response. We report a silicate, Li₂BaSiO₄, with edge-sharing LiO₄–SiO₄ tetrahedra that achieves the balance between a short UV absorption edge, below 190 nm, and a large SHG response, 2.8×KDP. The SHG intensity is the largest for silicates without second-order Jahn–Teller cations, and exceeds that of non-isomorphic Li₂SrSiO₄ by more than an order of magnitude. As such Li₂BaSiO₄ may be seen as a promising DUV-UV NLO material. This research indicates that edge-sharing tetrahedra is a new design parameter for discovering new DUV NLO materials.     

New nonlinear optical crystal: NaBa4Al2B8O18Cl3

Single crystals of NaBa(4)Al(2)B(8)O(18)Cl(3) have been grown with sizes up to 34 × 34 × 16 mm(3) from the NaF-LiCl flux by the top-seeded solution growth method. The compound crystallizes in the tetragonal system, space group P4(2)nm, with a = 12.0480 (16) ?, c = 6.8165 (11) ?, α = β = γ = 90°, and two formula units per cell. The NaBa(4)Al(2)B(8)O(18)Cl(3) compound is built up of infinite anionic groups of [AlB(4)O(12)](9-) formed by two BO(4) tetrahedra, one AlO(4) tetrahedra, and two BO(3) triangles. Optical properties including ultraviolet transmission, IR spectrum, and second-harmonic generation of NaBa(4)Al(2)B(8)O(18)Cl(3) crystals were reported. Refractive indices were measured by the minimum deviation technique and fitted to the Sellmeier equations. Thermal properties such as the DSC and thermal expansion were reported. The mechanical properties including the hardness, density, and chemical stability were also reported.     

LiGaGe2Se6: a new IR nonlinear optical material with low melting point

The new compound LiGaGe(2)Se(6) has been synthesized. It crystallizes in the orthorhombic space group Fdd2 with a = 12.501(3) ?, b = 23.683(5) ?, c = 7.1196(14) ?, and Z = 8. The structure is a three-dimensional framework composed of corner-sharing LiSe(4), GaSe(4), and GeSe(4) tetrahedra. The compound exhibits a powder second harmonic generation signal at 2 μm that is about half that of the benchmark material AgGaSe(2) and possesses a wide band gap of about 2.64(2) eV. LiGaGe(2)Se(6) melts congruently at a rather low temperature of 710 °C, which indicates that bulk crystals can be obtained by the Bridgman-Stockbarger technique. According to a first-principles calculation, there is strong hybridization of the 4s and 4p orbitals of Ga, Ge, and Se around the Fermi level. The calculated birefractive index is Δn = 0.04 for λ ≥ 1 μm, and the calculated major SHG tensor elements are d(15) = 18.6 pm/V and d(33) = 12.8 pm/V. This new material is promising for application in IR nonlinear optics.     

FeCl3-Catalyzed Condensation of 2-Naphthol and Aldehydes under Solvent-Free Reaction Conditions: An Efficient and Green Alternative for the Synthesis of 14-Aryl(Alkyl)-14-H-dibenzo[a, j]xanthenes

An iron‐catalyzed condensation of 2‐naphthol with aldehydes has been described. In the presence of a catalytic amount of iron(III) chloride (5 mol%), the condensation reaction of 2‐naphthol and aldehydes underwent smoothly to generate the corresponding products in good to excellent yields under base‐, acid‐, ligand‐, additive‐, and solvent‐free reaction conditions.     

NaGe3P3: a new ternary germanium phosphide featuring an unusual [Ge3P7] ring

A new ternary germanium phosphide, NaGe(3)P(3), was obtained for the first time with the use of NaP as the reactive flux. It crystallizes in the orthorhombic space group Pmc2(1). The basic structural unit is an unprecedented [Ge(3)P(7)] ring built from one Ge(P)(4) tetrahedron, one Ge(Ge)(P)(3) tetrahedron and one Ge(Ge)(P)(2) trigonal pyramid with Ge in mixed valences of 4+, 3+ and 1+. The bonding between a tetrahedrally coordinated Ge atom and a trigonal pyramidally coordinated Ge atom (with 4s(2) lone pair of electrons) is observed for the first time in inorganic compounds. These [Ge(3)P(7)] rings are connected with each other to form two-dimensional [Ge(3)P(3)](-) layers separated by Na(+) cations. An optical band gap of 2.06(2) eV was deduced from the diffuse reflectance spectrum. Based on the electronic structure calculation, NaGe(3)P(3) is an indirect gap semiconductor with the Ge 4s, Ge 4p and P 3p orbitals strongly hybridizing around the Fermi level.     

Iron-promoted tandem reaction of anilines with styrene oxides via C-C cleavage for the synthesis of quinolines

A novel iron-promoted tandem reaction of anilines with styrene oxides via C-C cleavage and C-H activation has been developed. The reaction utilizes an inexpensive FeCl(3) as promoter and is suitable for forming a variety of 3-arylquinolines from the simple and readily available starting materials.