Aggregates of self-propelling entities such as flocks of birds, schools of fish, bands of bacteria and motors in motility assays exhibit a zoo of striking, large scale collective behavior. Advances in the imaging of small scale biological systems (bacteria, cells) and increased computational power enabling the tracking of large-scale coherent structures (birds, insects) have led to a resurgence...

'Bioconvection' is the name given to pattern-forming convective motions set up in suspensions of swimming micro-organisms. 'Gyrotaxis' describes the way the swimming is guided through a balance between the physical torques generated by viscous drag and by gravity operating on an asymmetric distribution of mass within the organism. When the organisms are heavier towards the rear, gyrotaxis turns...

Hydrophilic fumed silica (FS) and precipitated silica (PS) powders were suspended in mineral oil; increasing the silica volume fraction (φ in the suspension led to the formation of sol, pre-gel, and gel states. Gelation took place at lower φ values in the FS than the PS suspension because of the lower silanol density on the FS surface. The shear stresses and dynamic moduli of the FS and PS susp...

We demonstrate a new approach for determining particle-size distribution in concentrated suspensions from spectral measurement of isotropic scattering coefficients by use of steady-state, continuous-wave photon-migration techniques. Successful recovery of particle-size distribution for TiO(2) suspensions in the form of log-normal functions is achieved through a regularized inverse algorithm, in...

to evaluate the physical and chemical stability of a suspension of mycophenolate mofetil (mmf) prepared in the hospital from commercially available mmf capsules and tablets. extemporaneous pharmacy was used as a feasible method in this experimental study to prepare suspension form of mmf. suspension formulations were prepared from both tablets and capsules forms of mmf. thereafter the stability...

conclusions in conclusion, the suspension containing veegum 1%, sodium carboxy methyl cellulose 1%, glycerine 0.2%, sodium citrate 0.3% and sorbitol 20 % was chosen as the most physically stable formulation. results according to the results, glycerin (0.2%) and sodium citrate (0.3%) had the best effect on the suspension stability as wetting and flocculating agents, respectively. rheological pro...

Tadalafil is a phosphodiesterase 5 inhibitor used orally as solid dosage form. The suspension of this drug has been used for pulmonary arterial hypertension treatment in pediatrics. The aim of this work was to investigate the influence of non-ionic surfactant (Tween 80) on the physical characteristics, drug particle size, and stress-shear rate rheogram of tadalafil 0.1% suspension. Several form...

three series of a polydispersed system of sulfadiazine and sulfamerazine mixture were prepared, and effect of three inorganic electrolytes on flocculation of this system was studied. we have found the appropriate flocculating agent and also its necessary concentration. results obtained have shown that there is a relation between flocculation and sedimentation volume, but the hard cake formed wh...