Unimodal Particle Size Research Articles

Nanoencapsulation of etoposide promotes increased long-term DNA damage, greater induction of senescence and reduces population regrowth of lung cancer cells

Lung cancer is the most common type of cancer and the leading cause of cancer-related deaths worldwide. The nanoencapsulation of etoposide, a topoisomerase II inhibitor and widely used chemotherapeutic drug, may overcome the limitations related to low aqueous solubility and non-specific toxicity, in addition to enabling a sustained release of etoposide and promoting long-term effects. Here we developed etoposide-loaded lipid-core nanocapsules (ETO NC) having unimodal particle size (∼150 nm), drug content of 0.5 mg mL−1 and encapsulation efficiency of ∼99 %. The formulation remained stable for 28 days at 5 °C. The release experiment showed 70 % of drug dialyzed from ETO NC within 72h in a biexponential curve characterized by a burst phase (60 %, t½ = 1.3 h) followed by a sustained phase (33 %, t½ = 173.2 h). Exposure of A549 lung adenocarcinoma cells to 10 μmol L−1 of drug (ETO NC) produced a threefold reduction in cell viability after 48h. Etoposide (ETO or ETO NC) produced DNA double-strand breaks, as indicated by nuclear foci in A549 cells stably expressing 53BP1-mApple. However, ETO NC significantly promoted nuclear damage over the long-term (20 days), consequently enhancing the induction of senescence and significantly reducing the proliferative subpopulation compared to etoposide in solution. Our findings reveal that ETO NC can enhance the long-term effects of etoposide in inducing DNA damage and inducing senescence, being an innovative strategy to overcome the limitations of this treatment, and strongly encouraging future investigations in in vivo models.

Improvement in head loss characteristics of fine particulate coal-water suspension with addition of coarser particulate

ABSTRACT An experimental study is performed to examine the pressure drop characteristics during the flow of coal-water slurry suspension using a pilot-plant test loop. The effect of slurry concentration, particle size, and flow velocity on the pressure drop characteristics during the transportation through a horizontal pipeline has been investigated. The present study considers both the unimodal and bimodal particle size distributions for the preparation of coal-water slurry. The pressure drop characteristics for both unimodal and bimodal coal-water slurry are analyzed for a wide variety of slurry concentrations ranging from 30% to 60%, which covers from low to high concentrations. The pressure drop characteristics are also analyzed for different flow velocities ranging from 2 to 5 m/s. It is found that the amount of pressure drop during the flow of coal-water slurry suspension in horizontal pipeline is the function of solid concentration, particle size, and flow velocity. It is also found that the bimodal coal-water slurry significantly reduces the pressure drop during the flow as compared to unimodal coal-water slurry. The maximum reduction in pressure drop during the flow is observed by bimodal coal-water slurry prepared by adding 30% of coarser particles in finer coal particles.

Concentration and size measurements of sprays with global rainbow technique

Simultaneous measurement of the concentration and size of spray droplets plays an important role in understanding sprays. The global rainbow technique is applied to measure the concentration and size of bi-component droplets. Based on the modified Nussenzweig theory, the refractive index and size distribution are optimally evaluated, and then the concentration is retrieved with prior relationship between the refractive index and concentration. The inverse algorithm is verified by the simulated global rainbow signals; results shows that it can accurately retrieve the refractive index and size distribution of the droplets with an unimodal or bimodal particle size distribution. Sprays of water-ethanol solution with volume concentration from 0% to 100% are measured. Results show that the measured refractive indices agree well with the exact values, and the size distribution is stable. The global rainbow technique shows great potential in concentration measurement of spray droplets.