Higher Order Dissipative-Dispersive System and Application

In this paper, a generalized nonlinear dissipative and dispersive equation with time and space-dependent coefficients is considered. We show that the control of the higher order term is possible by using an adequate weight function to define the energy. The existence and uniqueness of solutions are obtained via a Picard iterative method. As an application to this general Theorem, we prove the well-posedness of the Camassa-Holm type equation.     

An Efficient One-Pot Synthesis of Pyrazolopyrimidines, Intermediates for Potential Phosphodiesterase Inhibitors

Summary. A simple high-yielding procedure is presented for the synthesis of pyrazolopyrimidinones overcoming limitations found in earlier work and of considerable utility for the production of intermediates for potential phosphodiesterase inhibitors.     

New multi-1,2,3-selenadiazole aromatic derivatives

The aromatic polyketones 3a-d are versatile compounds for the synthesis of the multi-1,2,3-selenadiazole aromatic derivatives 1a-d. The preparation starts with the reaction between the multi-bromomethylene benzene derivatives 2a-d and 4-hydroxy- acetophenone to give compounds 3a-d which are transformed through the reaction with semicarbazide hydrochloride or ethyl hydrazine carboxylate into the corresponding semicarbazones derivatives 4a-d or hydrazones 5a-d. The reaction with selenium dioxide leads to regiospecific ring closure of semicarbazones or hydrazones to give the multi- 1,2,3-selenadiazole aromatic derivatives in high yield.     

Electric field effects on persistent spectral holes: Perylene in the polar polymer polyvinylbutyral

We investigated the effects of an electric field on a spectral hole burned in the inhomogeneously broadened S ₀–S ₁ transition of perylene in different samples of the polar polymer polyvinylbutyral (PVB) and in cellulose nitrate. The spectral hole is broadened and reduced in depth by the electric field. It was checked experimentally for perylene in PVB that the hole area remains constant when an electric field is applied. We determined the effective matrix-induced electric dipole moment differences * for perylene in different PVB samples and in cellulose nitrate. Within experimental accuracy the value of * is approximately independent of the composition of PVB and its water content. For perylene in cellulose nitrate the value of * is larger by a factor of 1.5 than in PVB. The results are discussed on the basis of a simple model for the electric field effect.     

Spectroscopic and HPLC methods for the determination of alendronate in tablets and urine

Two methods (spectrophotometric and HPLC) have been developed and validated for the analysis of alendronate sodium in tablet dosage form. Both methods depend on the ability of alendronate sodium to react with o-phthalaldehyde (OPA) at basic pH to produce a light-absorbing derivative. The derivative was found to possess absorption maximum at 330 nm where neither the derivatizing agent nor the analyte had any absorption. Thus, spectroscopic method was based on the derivatization-induced absorption of alendronate sodium at 333 nm. The HPLC method was based on separation of the formed derivative from other ingredients in tablets with detection at 333 nm. Both methods were satisfactory with regard to accuracy, prescion and linearity. Moreover, a HPLC method with fluorescence detection (HPLC-FD) was developed for the quantification of alendronate sodium in urine. The method was also based on the derivatization of alendronate with OPA, but fluorescence detection was employed. Linearity, recovery, selectivity, prescision and sensitivity were satisfactory for the proposed HPLC-FD method. Yet a new quantification limit (0.6 ng ml⁻¹) for alendronate in urine was achieved.     

Functionalized random copolymers from versatile one‐pot click chemistry/ATRP tandems approaches

Two complementary tandem strategies based on the one‐pot combination of click chemistry and atom transfer radical polymerization (ATRP) are studied. Initially, functionalized random copolymers are obtained by copolymerization of methyl methacrylate and propargyl methacrylate simultaneously to the click chemistry coupling of a monofunctional azide. Then, an approach based on the copolymerization of methyl methacrylate and 11‐azido‐undecanoyl methacrylate simultaneously to the click chemistry coupling of a monofunctional alkyne is also investigated. For both the approach, polymerization and click chemistry coupling are catalyzed by CuBr and bipyridine (Bipy) in diphenylether at 90 °C. The [Bipy]/[CuBr] ratio is varied from 2 to 25 and the ratio of functionalized comonomer from 20 to 70 mol %. Both the tandem strategies proceed with good yields (50–80%) and allow a good control over the characteristics of the resulting random copolymers and macromolecular brushes (M_n ～ 15,000–40,000 g/mol and PDI ～ 1.3–2.0) as well as quantitative click functionalization as characterized by ¹H NMR and size exclusion chromatography analyses. Although the click process is generally completed at the early stage of the process, the rate of polymerization depends on the amount of bipyridine involved. It was found that extending most of the polymerization process out of the click reaction regime results in a better control of the polymerization, preventing the significant occurrence of side reactions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3803–3813, 2009     

Facile Functionalization of Gold Nanoparticles with PLGA Polymer Brushes and Efficient Encapsulation into PLGA Nanoparticles: Toward Spatially Precise Bioimaging of Polymeric Nanoparticles

Nanocarriers prepared from poly(lactide‐co‐glycolide) (PLGA) have broad biomedical applications. Understanding their cellular uptake and distribution requires appropriate visualization in complex biological compartments with high spatial resolution, which cannot be offered by traditional imaging techniques based on fluorescent or radioactive probes. Herein, the encapsulation of gold nanoparticles (GNPs) into PLGA nanoparticles is proposed, which should allow precise spatial visualization in cells using electron microscopy. Available protocols for encapsulating GNPs into polymeric matrices are limited and associated with colloidal instability and low encapsulation efficiency. In this report, the following are described: 1) a facile protocol to functionalize GNPs with PLGA polymer followed by 2) encapsulation of the prepared PLGA‐capped GNPs into PLGA nanocarriers with 100% encapsulation efficiency. The remarkable encapsulation of PLGA‐GNPs into PLGA matrix obeys the general rule in chemistry “like dissolves like” as evident from poor encapsulation of GNPs capped with other polymers. Moreover, it is shown that how the encapsulated gold nanoparticles serve as nanoprobes to visualize PLGA polymeric hosts inside cancer cells at the spatial resolution of the electron microscope. The described methods should be applicable to a wide range of inorganic nanoprobes and provide a new method of labeling pharmaceutical polymeric nanocarriers to understand their biological fate at high spatial resolution.     

Symmetry reduction of sh-Lie structures and of local functionals

Reduced sh-Lie structures have been studied for the case when a Lie group acts on the fibers of a vector bundle while preserving the base space of the bundle. In this paper we investigate how one obtains a reduced sh-Lie structure using the ideas of symmetry reduction where the action of the Lie group is transversal to the fibers of the bundle. We also show how local functionals are reduced using these ideas.