Two simple and rapid spectrophotometric methods for the determination of a new antihypertensive drug olmesartan in tablets

Two simple, rapid and reproducible spectrophotometric methods have been described for the assay of olmesartan (OLM) in pharmaceutical formulation. The methods are based on the formation of ion associates in the reactions between the studied drug substance and ion-pair agents [bromocresol green (BCG) and bromophenol blue (BPB)]. By the extraction with dichloromethane and chloroform, yellow-colored ion associates were formed in acidic medium and absorbances were measured at 409 (BCG) and 412 nm (BPB). Optimizations of the reaction conditions were performed. Beer’s law was obeyed within the concentration range from 1–40 μg/mL and 10–120 μg/mL, respectively, for BCG and BPB. The molar absorptivity, detection and quantification limits were also determined. The developed methods were applied successfully to the determination of this drug in tablets.     

The behaviour of cationic NanoFibrillar Cellulose in aqueous media

This paper deals, with cationically modified NanoFibrillar Cellulose (cat NFC), obtained by reacting a dissolving pulp with 2,3-epoxypropyl trimethylammonium chloride (EPTMAC). The cat NFC was thoroughly characterized in terms of morphology and physical properties. The dimensions of individual cellulose nanofibrils were determined by atomic force microscopy (AFM) imaging in water and in air. Fibrils as thin as 0.8–1.2 nm were observed in water. The fibril diameter changed upon drying and the average size was further quantified by image analysis. The experiments showed the importance of characterizing nanocellulosic materials in situ before drying. The fibril size in air was confirmed by cryogenic transmission electron microscopy (cryo-TEM), and it was found to be 2.6–3.0 nm. Smooth ultrathin films of cationic NFC were prepared by spincoating on silica substrates. The effect of electrolyte concentration and pH on swelling of the cationic NFC film was studied using a quartz crystal microbalance with dissipation. The results showed that at pH = 8 the cat NFC film was insensitive to electrolyte changes while at pH = 4.5, the water content of the film decreased with increasing ionic strength. The electrophoretic mobility measurements showed a cationic zeta potential for the cat NFC that decreased at increasing pH, verifying the swelling behaviour.     

Synthesis of cyclopropane-annulated conduritol derivatives: norcaran-2,3,4,5-tetraoles

Norcaran-2,3,4,5-tetraoles were synthesized starting from methyl 1,3,5-cycloheptatriene-7-carboxylate in several steps. Norcaradiene endoperoxide is the key component; it was obtained by photooxygenation of methyl 1,3,5-cycloheptatriene-7-carboxylate. The other oxygen functionalities are introduced through epoxide ring opening and OsO₄-hydroxylation reactions.     

Multifractal analysis of non-uniformly hyperbolic systems

We prove a multifractal formalismfor Birkhoff averages of continuous functions in the case of some non-uniformly hyperbolic maps, which includes interval examples such as the Manneville-Pomeau map.     

Ostrowski Type Inequality for Double Integrals on Time Scales

We prove the Ostrowski type inequality for double integrals on time scales and thus unify corresponding continuous and discrete versions from the literature. We also apply the Ostrowski inequality for double integrals to the quantum time scales.     

Hybrid heuristics for the multi-stage capacitated lot sizing and loading problem

The multi-stage capacitated lot sizing and loading problem (MCLSLP) deals with the issue of determining the lot sizes of product items in serially-arranged manufacturing stages and loading them on parallel facilities in each stage to satisfy dynamic demand over a given planning horizon. It is assumed that regular time capacity decisions have already been made in the tactical level and allocated to the stages, but it is still an important decision problem whether to augment regular time capacity by overtime capacity. Each item may be processed on a technologically feasible subset of existing facilities with different process and setup times on each facility. Since the solution of the MCLSLP requires the design of a powerful algorithm, simulated annealing (SA) and genetic algorithms (GA) are integrated to enhance their individual performances. Furthermore, these global optimisation methods are incorporated into a Lagrangean relaxation scheme, hence creating a hybrid solution methodology. Numerical results obtained using these methods confirm the mutual benefits of integrating different solution techniques.     

New inequalities of Hermite-Hadamard type via s-convex functions in the second sense with applications

In this paper, we establish some new inequalities of Hermite-Hadamard type whose derivatives in absolute value are s-convex in the second sense. Finally some applications to special means of positive real numbers are given.     

Heat transfer effects on the stability of low speed plane Couette-Poiseuille flow

The stability problem of low-speed plane Couette-Poiseuille flow of air under heat transfer effects is solved numerically using the linear stability theory. Stability equations obtained from two-dimensional equations of motion and their boundary conditions result in an eigenvalue problem that is solved using an efficient shoot-search technique. Variable fluid properties are accounted for both in the basic flow and the perturbation (stability) equations. A parametric study is performed in order to assess the roles of moving wall velocity and heat transfer. It is found that the moving wall velocity and the location of the critical layers play decisive roles in the instability mechanism. The flow becomes unconditionally stable whenever the moving wall velocity exceeds half of the maximum velocity in the channel. With wall heating and Mach number effects included, the flow is stabilized.     

One‐Pot Synthesis of Multifunctional Polymers by Light‐Controlled Radical Polymerization and Enzymatic Catalysis with Candida antarctica Lipase B

The preparation of multifunctional polymers and block copolymers by a straightforward one‐pot reaction process that combines enzymatic transacylation with light‐controlled polymerization is described. Functional methacrylate monomers are synthesized by enzymatic transacylation and used in situ for light‐controlled polymerization, leading to multifunctional methacrylate‐based polymers with well‐defined microstructure.