A Conductive polylactic acid/polyaniline porous scaffold via freeze extraction for potential biomedical applications

This paper reports for the first time a simple yet effective method for fabricating a conductive and highly porous scaffold material made up of polylactic acid (PLA) and conducting polyaniline (PANI). The electrical percolation state was successfully obtained at 3 wt% of PANI inclusions and reached a conductivity level of useable tissue engineering applications at 4 wt%. In addition, preliminary bioactivity test results indicated that the protonating agent could form a chelate at the scaffold surface leading to good in-vitro apatite forming ability during biomimetic immersion. This new conductive scaffold has potential as a suitable biomedical material that requires electrical conductivity.     

Isolation and characterisation of three new anthraquinone secondary metabolites from Symplocos racemosa

Three new anthraquinone secondary metabolites were isolated from Symplocos racemosa, a small tree of family symplocaceae. The structures of compounds (1–3) were elucidated to be 1,4-dihydroxy-6-(ethoxymethyl)-8-propylanthracene-9,10-dione (1), 1,4-dihydroxy-6-(hydroxymethyl)-8-butylanthracene-9,10-dione (2) and 1,4-dihydroxy-6-(hydroxymethyl)-8-propyl anthracene-9,10-dione (3) using their spectral data, i.e. through IR, UV, ¹H NMR, ¹³C NMR and two-dimensional (2D) NMR techniques including heteronuclear multiple quantum coherence, heteronuclear multiple bond correlation and correlation spectroscopy.     

Chemically stable silver nanoparticle-crosslinked polymer microspheres

Stabilization of metal nanoparticles (MNP) is a prerequisite for any application in sensor design, optoelectronics, catalysis, spectroscopic labeling, and nanomedicine. However, MNPs produced by most currently available synthetic approaches tend to undergo aggregation into large clusters, thus reducing their accessibility and compromising properties associated with their nanoscale dimensions. To circumvent the agglomeration problem and enhance their chemical and physical stability, we developed an efficient strategy for the preparation of MNP/polymer composites in which silver nanoparticles coated with 4-mercaptomethylstyrene act as crosslinkers in a suspension polymerization. The resulting microspheres were characterized by Raman, SERS and XPS spectroscopies, DSC, SEM and TEM. Their chemical and physical stability was also established.     

Calorimetric investigations of the hydrolytic degradation for a series of β-sultams

The hydrolytic degradation of four β-sultams was investigated using isothermal microcalorimetry to determine kinetic and enthalpic data. Firstly, all four compounds were analysed in the solid-state at 310 K, with a significant substituent-based stabilising/destabilising effect being observed. Secondly, the four compounds were analysed in the presence of pH 4 acetate buffer, at three temperatures (298, 310 and 323 K). Under these conditions, the substituent choice affected the rate of hydrolysis and the associated change in enthalpy for each compound. Based on the calorimetric data presented in this work, no change in reaction mechanism for the hydrolytic degradation was observed over the temperature range considered.     

Efficient and reusable Cu (II)-metalated silica-based inorganic-organic hybrid catalyst for dye degradation

An efficient silica-based inorganic-organic hybrid was synthesized by using 3-(2-aminoethylamino)propyltrimethoxylsilane as linker and 2-Quinolinecarboxaldehyde for Schiff's base formation which was further coordinated by Cu (II) chloride. The hybrid was characterized by relevant techniques, i.e., FT-IR, DRUV-Vis, SEM, EDX, ICP-AES, TGA and EPR technique which support its formation. The synthesized hybrid material was successfully used as heterogeneous catalyst for degrading Reactive Black-5 (RB-5), a non-biodegradable diazo dye. The degradation mechanism follows advanced oxidation technique utilizing hydrogen peroxide as an environmentally amiable green oxidant; where the hybrid catalyst decomposes H₂O₂ to generate ·OH free radicals. Effects of dye concentration, H₂O₂ concentration and temperature variation on dye degradation process were studied and best reaction conditions for maximum degradation of RB-5 were also worked out. The catalyst showed 87% dye degradation in 130 ?min at best reaction conditions. Easy separation, reusability and efficient dye degradation ability of the catalyst are the motivating factors for the development of such hybrid material for solving critical environmental issues.     

Biotransformation of perfumery terpenoids, ()- ambrox(R) by a fungal culture Macrophomina phaseolina and a plant cell suspension culture of Peganum harmala

ABSTRACT: BACKGROUND: Biotransformation offers chemo enzymatic system to modify the compounds into their novel analogues which are difficult to synthesize by chemical methods. This paper describes the biotransformational studies of ambrox, one of the most important components of natural Ambergris (wale sperm) with fungal and plant cell culture. RESULTS: Biotransformation of ()-ambrox (1) with a fungal cell culture of Macrophomina phaseolina and a plant cell suspension cultures of Peganum harmala yielded oxygenated products, 3beta- hydroxyambrox (2), 6beta-hydroxyambrox (3), 1alpha-hydroxy-3oxoambrox (4), 1alpha,3beta- dihydroxyambrox (5), 13,14,15,16-tetranorlabdane-3-oxo-8,12-diol (6), 3-oxoambrox (7), 2alpha- hydroxyambrox (8), 3beta-hydroxysclareolide (9), and 2alpha,3beta-dihydroxyambrox (10). Metabolite 4 was found to be new compound. These metabolites were structurally characterized on the basis of spectroscopic studies. CONCLUSION: Nine oxygenated metabolites of ()-ambrox (1) were obtained from Macrophomina phaseolina and Peganum harmala. Enzymatic system of screened organisms introduced hydroxyl and keto functionalities at various positions of compound 1 in a stereo- and regiocontrolled manner.     

Block-based disparity estimation by partial finite ridgelet distortion search (PFRDS)

In stereo vision applications, computing the disparity map is an important issue. Performance of different approaches totally depends on the employed similarity measurements. In this paper finite ridgelet transform is used to define an edge sensitive block distortion similarity measure. Simulation results emphasize to outperform in the conventional criteria and is less sensitive to noise, especially at the edge set of images. To speed computations, a new partial search algorithm based on energy conservation property of FRIT is proposed.     

Theoretical investigation of the coordination of dibenzazepine to transition-metal complexes: A DFT study

DFT calculations with full geometry optimizations have been carried out on a series of hypothetical compounds of the CpM(C₁₄NH₁₁) and (CO)₃M(C₁₄NH₁₁) (M = transition metal and C₁₄NH₁₁ = dibenzazepine ligand) type. A rationalization of the bonding in hypothetical complexes is provided. Depending on the electron count and the nature of the metal, the dibenzazepine ligand can bind to the metal through the η¹, η², η³, η⁴ , η⁵, η⁶ , or η⁷ coordination mode adopting structures of types a or b. In the investigated species, the most favored closed-shell count is 18-MVE except for the Sc and V models which prefer the 16-MVE configuration.     

Real Paley-Wiener type theorems for the Dunkl transform on {\mathcal{S}}'(\mathbb{R}^{d})

We prove real Paley-Wiener type theorems for the Dunkl transform ℱ _D on the space of tempered distributions. Let T∈S′(ℝ ^d ) and Δ _κ the Dunkl Laplacian operator. First, we establish that the support of ℱ _D (T) is included in the Euclidean ball , M>0, if and only if for all R>M we have lim  _n→+∞ R ⁻²ⁿ Δ _κ ⁿ T=0 in S′(ℝ ^d ). Second, we prove that the support of ℱ _D (T) is included in ℝ ^d ∖B(0,M), M>0, if and only if for all R<M, we have lim  _n→+∞ R ²ⁿ  ℱ _D ⁻¹(‖y‖⁻²ⁿ ℱ _D (T))=0 in S′(ℝ ^d ). Finally, we study real Paley-Wiener theorems associated with -slowly increasing function.      

Conservation laws and conserved quantities for laminar two-dimensional and radial jets

A systematic way to derive the conserved quantities for the liquid jet, free jet and wall jet using conservation laws is presented. Both two-dimensional and radial jets are considered. The jet flows are described by Prandtl’s momentum boundary layer equation and the continuity equation. The multiplier approach (also know as variational derivative approach) is first applied to construct a basis of conserved vectors for the system. The basis consists of two conserved vectors. By integrating the corresponding conservation laws across the jet and imposing the boundary conditions, conserved quantities are derived for the liquid jet and the free jet. The multiplier approach is then applied to construct a basis of conserved vectors for the third-order partial differential equation for the stream function. The basis consists of two local conserved vectors one of which is a non-local conserved vector for the system. The conserved quantities for the free jet and the wall jet are derived from the corresponding conservation laws and boundary conditions. The approach gives a unified treatment to the derivation of conserved quantities for jet flows and may lead to a new classification of jets through conserved vectors and their multipliers.