Nonlinear deformation of a ferrofluid droplet in a uniform magnetic field

This paper reports experimental and numerical results of the deformation of a ferrofluid droplet on a superhydrophobic surface under the effect of a uniform magnetic field. A water-based ferrofluid droplet surrounded by immiscible mineral oil was stretched by a magnetic field parallel to the substrate surface. The results show that an increasing flux density increases the droplet width and decreases the droplet height. A numerical model was established to study the equilibrium shape of the ferrofluid droplet. The governing equations for physical fields, including the magnetic field, are solved by the finite volume method. The interface between the two immiscible liquids was tracked by the level-set method. Nonlinear magnetization was implemented in the model. Comparison between experimental and numerical results shows that the numerical model can predict well the nonlinear deformation of a ferrofluid droplet in a uniform magnetic field.Accepted versio

Nanosized TiO2-induced reproductive system dysfunction and its mechanism in female mice.

Recent studies have demonstrated nanosized titanium dioxide (nano-TiO2)-induced fertility reduction and ovary injury in animals. To better understand how nano-TiO2 act in mice, female mice were exposed to 2.5, 5, and 10 mg/kg nano-TiO2 by intragastric administration for 90 consecutive days; the ovary injuries, fertility, hormone levels, and inflammation-related or follicular atresia-related cytokine expression were investigated. The results showed that nano-TiO2 was deposited in the ovary, resulting in significant reduction of body weight, relative weight of ovary and fertility, alterations of hematological and serum parameters and sex hormone levels, atretic follicle increases, inflammation, and necrosis. Furthermore, nano-TiO2 exposure resulted in marked increases of insulin-like growth factor-binding protein 2, epidermal growth factor, tumor necrosis factor-α, tissue plasminogen activator, interleukin-1β, interleukin -6, Fas, and FasL expression, and significant decreases of insulin-like growth factor-1, luteinizing hormone receptor, inhibin α, and growth differentiation factor 9 expression in mouse ovary. These findings implied that fertility reduction and ovary injury of mice following exposure to nano-TiO2 may be associated with alteration of inflammation-related or follicular atresia-related cytokine expressions, and humans should take great caution when handling nano-TiO2

Histopathological observation of ovary of mice caused by intragastric administration of nano-TiO₂ for 90 consecutive days.

<p>(a) control groups (unexposed mice) present normal development of primary follicle and secondary follicle; (b) 2.5 mg/kg nano-TiO₂-exposed group: green cycle suggest inflammatory cell infiltration, yellow arrows indicate atretic follicle, red arrows present apoptosis or tissue necrosis; (c) 5 mg/kg nano-TiO₂-exposed group: green cycle suggest severe inflammatory cell infiltration, yellow cycles present nano-TiO₂ deposition, yellow arrows indicate atretic follicle, red arrows present apoptosis or tissue necrosis in ovary; (d) 10 mg/kg nano-TiO₂ -exposed group: green cycle suggest severe inflammatory cell infiltration, yellow arrows indicate atretic follicle, red arrows present tissue necrosis, yellow cycle may show aggregation of nano-TiO₂ in ovary. Arrow A spot is a representative cell that not engulfed the nano-TiO₂, while arrow B spot denotes a representative cell that loaded with nano-TiO₂. The right panels show the corresponding Raman spectra identifying the specific peaks at about 148 cm⁻¹.</p

Effects of nano-TiO₂ on sex hormone levels in sera of female mice.

<p>Different letters indicate significant differences between groups (p<0.05). Values represent means ± SE (N = 5).</p

Changes of body weight and relative weight of ovary of mice caused by intragastric administration of nano-TiO₂ for 90 consecutive days.

<p>Different letters indicate significant differences between groups (p<0.05). Values represent means ± SE (N = 10).</p