The flow of blood in an inclined artery with an axially non-symmetrical but radially symmetrical mild stenosis has been presented in this study. To account for the slip at stenotic wall, hematocrit and inclination of the artery, blood has been represented by a particle-fluid suspension. The expression for the flow characteristics, namely, the impedance (resistance to flow), the wall shear stress and the shear stress at the throat of the stenosis have been derived and represented graphically with respect to different flow parameters. The impedance increases with the hematocrit and stenosis size but decreases with slip at wall and angle of inclination of the artery. The shear stress at the maximum stenosis height increases with the inclination of the artery but possess the characteristics similar to that of impedance with respect to other parameters. As an application, theoretical values of effective viscosity computed with the help of the present analysis are compared with experimental results and found that they are in reasonable agreement for low hematocrit values in small blood carrying vessels.

A simple, high-throughput and specific high-performance liquid chromatography tandem mass spectrometry method has been developed and validated according to the FDA guidelines for simultaneous quantification of olmesartan and pioglitazone in rat plasma. The bioanalytical method consists of liquid-liquid extraction and quantitation by triple quadrupole mass spectrometry using electrospray ionization technique, operating in multiple reaction monitoring and positive ion modes. The compounds were eluted isocratically on a C(18) column with a mobile phase consisting of a mixture of methanol and water (containing 0.5% formic acid) in a ratio of 9:1. The response to olmesartan and pioglitazone was linear over the range 0.01-10 µg/mL. The validation results demonstrated that the method had satisfactory precision and accuracy across the calibration range. Intra- and inter-day precisions ranged from 0.66 to 3.32 and from 0.94 to 2.93% (%CV), respectively. The accuracy determined at three quality control levels was within 91.27-107.28%. There was no evidence of instability of the analytes in rat plasma following the stability studies. The method proved highly reproducible and sensitive and was successfully applied in a pharmacokinetic study after single dose oral administration of olmesartan and pioglitazone to the rat.

No abstract

The concept of nil-symmetric rings has been introduced as a generalization of symmetric rings and a particular case of nil-semicommutative rings. A ringRis called right (left) nil-symmetric if, fora,b,c∈R, wherea,bare nilpotent elements,abc=0  (cab=0)impliesacb=0. A ring is called nil-symmetric if it is both right and left nil-symmetric. It has been shown that the polynomial ring over a nil-symmetric ring may not be a right or a left nil-symmetric ring. Further, it is also proved that ifRis right (left) nil-symmetric, then the polynomial ringR[x]is a nil-Armendariz ring.

The present study is concerned with the flow of blood in an artery with an overlapping mild stenosis. To account for the slip at stenotic wall, hematocrit, pulsatility of flow and inclination of the tube, blood has been represented by a fluid whose viscosity varies with radial coordinate and hematocrit. The expression for the flow characteristics, namely, the wall shear stress, the shear stress at the critical height of the stenosis, the pressure drop and the resistance to flow (impedance) have been derived and represented graphically with respect to different flow parameters. The resistance to flow increases with the hematocrit and critical height of the stenosis but decreases with slip at wall. With respect to any parameter, the shear stress at the critical height possesses the characteristics similar to that of the impedance.