Mimicking Nanofibrous Hybrid Bone Substitute for Mesenchymal Stem Cells Differentiation into Osteogenesis

Mimicking hybrid extracellular matrix is one of the main challenges for bone tissue engineering (BTE). Biocompatible polycaprolactone/poly(α,β)‐DL ‐aspartic acid/collagen nanofibrous scaffolds were fabricated by electrospinning and nanohydroxyapatite (n‐HA) was deposited by calcium phosphate dipping method for BTE. Human mesenchymal stem cells (hMSCs) were cultured on these hybrid scaffolds to investigate the cell proliferation, osteogenic differentiation by alkaline phosphatase activity, mineralization, double immunofluorescent staining using CD90 and expression of osteocalcin. The present study indicated that the PCL/PAA/collagen/n‐HA scaffolds promoted greater osteogenic differentiation of hMSCs, proving to be a potential hybrid scaffolds for BTE.

     

Micromanipulation of Mechanically Compliant Organic Single‐Crystal Optical Microwaveguides

Flexible organic single crystals are evolving as new materials for optical waveguides that can be used for transfer of information in organic optoelectronic microcircuits. Integration in microelectronics of such crystalline waveguides requires downsizing and precise spatial control over their shape and size at the microscale, however that currently is not possible due to difficulties with manipulation of these small, brittle objects that are prone to cracking and disintegration. Here we demonstrate that atomic force microscopy (AFM) can be used to reshape, resize and relocate single‐crystal microwaveguides in order to attain spatial control over their light output. Using an AFM cantilever tip, mechanically compliant acicular microcrystals of three N‐benzylideneanilines were bent to an arbitrary angle, sliced out from a bundle into individual crystals, cut into shorter crystals of arbitrary length, and moved across and above a solid surface. When excited by using laser light, such bent microcrystals act as active optical microwaveguides that transduce their fluorescence, with the total intensity of transduced light being dependent on the optical path length. This micromanipulation of the crystal waveguides using AFM is non‐invasive, and after bending their emissive spectral output remains unaltered. The approach reported here effectively overcomes the difficulties that are commonly encountered with reshaping and positioning of small delicate objects (the “thick fingers” problem), and can be applied to mechanically reconfigure organic optical waveguides in order to attain spatial control over their output in two and three dimensions in optical microcircuits.     

Synthesis, DNA binding, antioxidant and cytotoxic activities of ruthenium(II) complexes of a Schiff base ligand

Three ruthenium(II) complexes, [Ru(CO)Cl(PPh₃)L], [Ru(CO)Cl(AsPh₃)L] and [Ru(CO)Cl(Py)L], were synthesized from the reactions of 2-(benzothiazol-2-yliminomethyl)-phenol (HL) with [RuHCl(CO)B(EPh₃)₂], where B = PPh₃, AsPh₃ or pyridine, and E = P or As. All the complexes have been characterized by physicochemical and spectroscopic methods. The structure of the free ligand HL was determined by single crystal X-ray diffraction. The binding of the free ligand and its complexes with CT-DNA was studied using electronic absorption spectroscopy. In addition, the free ligand and its complexes were subjected to antioxidant activity tests, which showed that they all possess significant scavenging effects against DPPH and OH radicals. The in vitro cytotoxicities of the compounds were assessed using tumor (HeLa and MCF-7) cell lines.     

Supramolecular architectures of two novel organic–inorganic hybrid materials containing identical monomeric uranyl units

Two isostructural uranyl complexes have been crystallized with different bipyridyl cations to yield the compounds hemi(4,4′‐bipyridinium) tris(5‐chlorothiophene‐2‐carboxylato)dioxidouranate(VI) monohydrate, (C₁₀H₁₀N₂)_0.5[U(C₅H₂ClO₂S)₃O₂]·H₂O, (I), and hemi[4,4′‐(ethane‐1,2‐diyl)dipyridinium] tris(5‐chlorothiophene‐2‐carboxylato)dioxidouranate(VI) monohydrate, (C₁₂H₁₄N₂)_0.5[U(C₅H₂ClO₂S)₃O₂]·H₂O, (II). In the [UO₂X₃]⁻ complexes (X is 5‐chlorothiophene‐2‐carboxylate), the uranyl O atoms occupy the two axial positions and the equatorial positions are occupied by six O atoms of the three X ions so that each U atom is eight coordinated in a puckered hexagonal–bipyramidal structure. In both compounds, the metal centres are linked by classical O—H...O and N—H...O hydrogen bonds involving the coordinated ligands, the diprotonated organic linker cation (which rests on a centre of inversion at the mid‐point of the central C—C bond) and water molecules. The crystal structures are further stabilized by weak C—H...O and π–π stacking interactions, forming similar three‐dimensional supramolecular architectures, forming a two‐dimensional network parallel to the (100) plane in (I) and a three‐dimensional network in (II).     

The Effect of Naphthalene-Acetic Acid on Biomass Productivity and Chlorophyll Content of Green Algae,Coccolithophore, Diatom,and Cyanobacterium Cultures

The application of biochemical stimulants to enhance biomass and metabolite productivity is being investigated here and may be a simpler approach to achieve our goals of higher productivity and lower costs than methods such as genetic modification. The research builds on prior work of screening various biochemical stimulants representing different types of plant growth regulators with the green alga, Chlorella sorokiniana. Here, we report the impact on biomass and chlorophyll productivity by comparing the delivery method of a previously identified superior stimulant, the synthetic auxin naphthalene-acetic acid (NAA), solubilized in ethanol or methanol. Algae evaluated included the green alga, C. sorokiniana, as well as a mixed consortium that includes C. sorokiniana along with two other wild-isolated green algae, Scenedesmus bijuga and Chlorella minutissima. It was found that NAA dissolved in ethanol was more effective in enhancing biomass productivity of C. sorokiniana. However, no differences were observed with the mixed consortia. The most effective treatment from this step, EtOH_500ppm + NAA_5ppm, along with two other NAA concentrations (EtOH_500ppm + NAA_2.5ppm and EtOH_500ppm + NAA_10ppm), was then applied to six diverse species of microalgae to determine if the treatment dosage was effective for other freshwater and marine green algae, cyanobacteria, coccolithophore, and diatoms. It was found that three of the species bioassayed, Pleurochrysis carterae, C. sorokiniana, and Haematococcus pluvialis exhibited a substantial boost in biomass productivity over the 10-day growth period. The use of ethanol and NAA at a combined dosage of EtOH_500ppm + NAA_5ppm was found to generate the highest biomass productivity for each of the species that responded positively to the treatments. If scalable, NAA and ethanol may have the potential to lower production costs by increasing biomass yields for commercial microalgae cultivation.     

Affine PBW bases and MV polytopes in rank 2

Mirkovi?–Vilonen (MV) polytopes have proven to be a useful tool in understanding and unifying many constructions of crystals for finite-type Kac-Moody algebras. These polytopes arise naturally in many places, including the affine Grassmannian, pre-projective algebras, PBW bases, and KLR algebras. There has recently been progress in extending this theory to the affine Kac-Moody algebras. A definition of MV polytopes in symmetric affine cases has been proposed using pre-projective algebras. In the rank-2 affine cases, a combinatorial definition has also been proposed. Additionally, the theory of PBW bases has been extended to affine cases, and, at least in rank-2, we show that this can also be used to define MV polytopes. The main result of this paper is that these three notions of MV polytope all agree in the relevant rank-2 cases. Our main tool is a new characterization of rank-2 affine MV polytopes.     

Multivalued fixed point in Banach algebra using continuous selection and its application to differential inclusion

In this paper, we provide some fixed point results using continuous selection given by Poonguzali et al. [15]. Also, using the selection theorem we discusse the existence of fixed point for the product of two multivalued mappings, that is, of the form $Ax\cdot Bx.$ Using those fixed point results, we give the existence of solution for a newly developed differential inclusion.     

Hydrogen‐bonding patterns in pyrimethaminium dinitrate

The title compound, 2,4‐diamino‐5‐(4‐chloro­phen­yl)‐6‐ethyl­pyrimidine‐1,3‐diium dinitrate, C₁₂H₁₅ClN₄²⁺·2NO₃⁻, contains two crystallographically independent pyrimethamine (PMN) mol­ecules, which differ in the relative orientations of the pyrimidine and benzene rings and of the eth­yl substitutents. In both pyrimethamine mol­ecules, all the pyrimidine N atoms are protonated, unlike most related compounds, in which only one pyrimidine N atom is protonated. The two pyrimethamine moieties are bridged by a variety of N—H⋯O(nitrate) inter­actions, including some three‐centre hydrogen bonds.