A subdivision collocation method for solving two point boundary value problems of order three

In this paper, we propose a method for the numerical solution of self adjoint singularly perturbed third order boundary value problems in which the highest order derivative is multiplied by a small parameter $\varepsilon$. In this method, first we introduce the derivatives of two scale relations satisfied by the subdivision schemes. After that we use these derivatives to construct the subdivision collocation method for the numerical solution of singularly perturbed boundary value problems. Convergence of the subdivision collocation method is also discussed. Numerical examples are presented to illustrate the proposed method.     

Molecularly imprinted polymer Based PVC-Membrane-Coated graphite electrode for the determination of metoprolol

A PVC-based membrane containing metoprolol molecularly imprinted polymer (MIP) coated directly on graphite electrode for the determination of metoprolol in real samples is reported. This potentiometric sensor was designed by dispersing the MIP particles in dioctylphthalate plasticizer as solvent mediator and then embedded in polyvinyl chloride matrix. The electrode exhibited a near-Nernstian slope of 55.4 ± 1 mV decade^-1 for metoprolol over a wide concentration range between 2.0 × 10^-7-8.0 × 10^-3 M and a detection limit of 1.3 × 10^-7 M. With a response time of about 14 s it could be used for at least 6 months without any divergence in potential. The proposed electrode can be used in the pH range of 3.5-10.5 and can reveal good selectivities for metoprolol over a wide variety of ions. Finally, the designed sensor was successfully applied as an indicator electrode to determine the concentration of metoprolol in tablets, human urine and plasma. The results were compared favorably with those obtained by HPLC method and showed satisfactory agreements with them.     

A synthesis of the γ-secretase inhibitor BMS-708163

A concise, convergent racemic synthesis of BMS-708163 is reported. Two fragments consisting of N-4-chlorophenylsulfonyl-3,3,3-trifluorpropylglycine and a 1,2,4-oxadiazole derivative of 2-fluorobenzyl alcohol were prepared in separate pots and then coupled together via a Mitsunobu reaction. Since a convenient chiral synthesis of optically pure (d)-3,3,3-trifluoropropyl glycine methyl ester was developed using Schöllkopf reagent alkylation, this methodology can also be adopted for the enantioselective synthesis of BMS-708163.     

Solid-Phase Extraction of Metoprolol onto(Methacrylic acid-ethylene glycol dimethacrylate)-based Molecularly Imprinted Polymer and Its Spectrophotometric Determination

A new adsorbent for molecularly imprinted solid phase extraction (MISPE) of metoprolol was synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross‐linking agent causing a non‐covalent, bulk, thermal radical‐polymerization. Control polymer (non‐imprinted polymer) was prepared under well defined conditions without the use of metoprolol. The synthesized polymers were characterized by IR spectroscopy, X‐ray diffraction and thermal analysis techniques. This polymer was used for the rapid extraction and preconcentration of metoprolol from real samples prior to spectrophotometric determination. Extraction efficiency and the influence of flow rates of sample and stripping solutions, pH, type of eluent for elution of metoprolol from polymer, break through volume and limit of detection were studied. The detection limit of the proposed method is 0.4 ng·mL^?1. The method was applied successfully to the recovery and determination of metoprolol in tablets, human urine and plasma samples.     

A Note on Classification of Teleparallel Conformal Vector Fields in Cylindrically Symmetric Static Space-Times in the Teleparallel Theory of Gravitation

In this paper we explored teleparallel conformal vector fields in cylindrically symmetric static space-times in the teleparallel theory of gravitation by using the direct integration technique. It turns out that the dimension of teleparallel conformal vector fields are 8, 9, 10 or 11. The case VI in which the space-time becomes conformally flat admits eleven independent teleparallel conformal vector fields.     

Alpha-glucosidase inhibitory constituents from Cuscuta reflexa

Two new compounds, 7'-(3',4'-dihydroxyphenyl)-N-[(4-methoxyphenyl)ethyl]propenamide (4), and 7'-(4'-hydroxy,3'-methoxyphenyl)-N-[(4-butylphenyl)ethyl]propenamide (5) have been isolated from Cuscuta reflexa along with five known compounds, 6,7-dimethoxy-2H-1-benzopyran-2-one (1), 3-(3,4-dihydroxyphenyl)-2-propen-1-ethanoate (2), 6,7,8-trimethoxy-2H-1-benzopyran-2-one (3), 3-(4-O-beta-D-glucopyranoside-3,5-dimethoxyphenyl)-2-propen-1-ol (6), 2-(3-hydroxy-4-methoxyphenyl)-3,5-dihydroxy-7-O-beta-D-glucopyranoside-4H-1-benzopyrane-4-one (7), reported for the first time from this species. Structures of these compounds were determined by spectral analysis. These compounds showed strong inhibitory activity against alpha-glucosidase.     

Synthesis and anti-inflammatory activity of fluorinated isocoumarins and 3,4-dihydroisocoumarins

The synthesis of several fluorinated isocoumarins and 3,4-dihydroisocoumarins are described. The structures of the synthesized compounds were confirmed by spectral and elemental analysis. All synthesized compounds were evaluated for their anti-inflammatory and antioxidant activity. These compounds were found to present antioxidant and anti-inflammatory activities. A few of them were found to be significantly active in vivo against ear edema in mice produced by 12-O-tetradecanoylphorbol-13-acetate (TPA) and also good radical scavengers.     

Clouding behavior of nonionic–cationic and nonionic–anionic mixed surfactant systems in presence of carboxylic acids and their sodium salts

The study is focused on evaluation of clouding phenomena of the aqueous single nonionic surfactant system Triton X-100 (TX-100) and its mixed systems with anionic aerosol-OT (AOT) and cationic dodecylpyridinium chloride (DPC) in presence of hydrophobic ions furnished by sodium salts of carboxylic acids, viz., sodium ethanoate, sodium propanoate, sodium butanoate, and sodium hexanoate and the respective carboxylic acids [ethanoic acid, propanoic acid, butanoic acid, and hexanoic acid]. The influence of salts on the cloud point (CP) has been explained on the basis of salt effect as well as the solubilization of higher alkyl chain hydrophobic ions furnished by these salts. Moreover, the co- and counterion effect has been taken into account to explain the variation of the CP in the mixed systems. However, the effect of acids on CP has been explained in the light of their aqueous solubility and their partitioning ability between octanol and water as reflected by their K _OW values.     

Microbial transformation of dehydroepiandrosterone

Transformation of dehydroepiandrosterone (DHEA) (1) was carried out by a plant pathogen Rhizopus stolonifer, which resulted in the production of seven metabolites. These metabolites were identified as 3beta,17beta-dihydroxyanandrost-5-ene (2), 3beta,17beta-dihydroxyandrost-4ene (3), 17beta-hydroxyandrost-4-ene-3-one (4), 3beta,11-dihydroxyandrost-4-ene-17-one (5), 3beta,7alpha-dihydroandrost-5-ene-17-one (6), 3A,7alpha,17beta-trihydroxyandrost-5-ene (7) and 11beta-hydroxyandrost-4,6-diene-3,17-dione (8). The structures of the transformed products were determined by the spectroscopic techniques.