4D Investigation of Vortex Fluid Motion Inside the Eyeball

2021 ◽  
pp. 73-88
Author(s):  
S.A. Skladchikov ◽  
N.P. Savenkova ◽  
P.I. Vysikaylo ◽  
S.E. Avetisov ◽  
D.V. Lipatov ◽  
...  
Keyword(s):  
Numerical Models ◽  
Fluid Motion ◽  
Vortex Motion ◽  
Dissipative System ◽  
Fluid Flows ◽  
Vitreous Cavity ◽  
Posterior Chamber ◽  
Medicinal Substance ◽  
Fluid Transfer ◽  
And Diffusion

The eye is a complex system of boundaries and fluids with different viscosities within the boundaries. At present, there are no experimental possibilities to thoroughly observe the dynamic 4D processes after one or another method of eye treatment is applied. The complexity of cumulative, i.e., focusing, and dissipative, i.e., scattering, convective and diffusion 4D fluxes of fluids in the eye requires 4D analytical and numerical models of fluid transfer in the human eyeball to be developed. The purpose of the study was to develop and then verify a numerical model of 4D cumulative-dissipative processes of fluid transfer in the eyeball. The study was the first to numerically evaluate the values of the characteristic time of the drug substance in the vitreous cavity until it is completely washed out, depending on the injection site; to visualize the paths of the vortex motion of the drug in the vitreous cavity; to determine the main parameters of the 4D fluid flows of the medicinal substance in the vitreous cavity, depending on the presence or absence of vitreous detachment from the wall of the posterior chamber of the eye. The results obtained are verified by the experimental data available to doctors. In the eye, as a partially open cumulative-dissipative system, Euler regions with high rates of cumulative flows and regions with low speeds or stagnant Lagrange flow zones are defined

scholarly journals Copulation, genital damage and early death in Callosobruchus maculatus

2006 ◽  
Vol 274 (1607) ◽  
pp. 247-252 ◽  
Author(s):  
Paul E Eady ◽  
Leticia Hamilton ◽  
Ruth E Lyons
Keyword(s):  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Seminal Fluid ◽  
Negative Impact ◽  
Early Death ◽  
Female Reproductive Tract ◽  
Mating Frequency ◽  
Trade Off ◽  
Female Longevity ◽  
Fluid Transfer

Antagonistic sexual coevolution stems from the notion that male and female interests over reproduction are in conflict. Such conflicts appear to be particularly obvious when male genital armature inflicts damage to the female reproductive tract resulting in reduced female longevity. However, studies of mating frequency, genital damage and female longevity are difficult to interpret because females not only sustain more genital damage, but also receive more seminal fluid when they engage in multiple copulations. Here, we attempt to disentangle the effects of genital damage and seminal fluid transfer on female longevity in the beetle Callosobruchus maculatus (Coleoptera: Bruchidae). Males copulating for the sixth time in succession inflicted greater levels of genital damage, but transferred smaller ejaculates in comparison with virgin males. The number of copulations performed by males was negatively related to female fecundity and positively related to female longevity, suggesting a trade-off between fecundity and longevity. However, inclusion of fecundity as a covariate revealed sperm and/or seminal fluid transfer to have a negative impact on female longevity above that caused by the fecundity–longevity trade-off. The consequences of multiple copulations on female longevity were examined. Females that mated twice laid more eggs and died sooner than those that mated once. However, incorporation of fecundity as a covariate into our statistical model removed the effect of female mating frequency on female longevity, indicating that double-mated females suffer greater mortality owing to the trade-off between fecundity and longevity. Males of this species are known to transfer very large ejaculates (up to 8% of their body weight), which may represent a significant nutritional benefit to females. However, the receipt of large ejaculates appears to carry costs. Thus, the interpretation of multiple mating experiments on female longevity and associated functional explanations of polyandry in this species are likely to be complex.

Study on the Range of Freeze-Thaw of Surrounding Rock from a Cold-Region Tunnel and the Effects of Insulation Material

2011 ◽  
Vol 399-401 ◽  
pp. 2222-2225 ◽  
Author(s):  
Peng Qi ◽  
Jing Zhang ◽  
Zhi Rong Mei ◽  
Yue Xiu Wu
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Surrounding Rock ◽  
Insulation Material ◽  
The Finite Element Method ◽  
Cold Region ◽  
Coupled Problem ◽  
Fluid Transfer ◽  
Tunnel Depth ◽  
The Relationship

A mathematical models for the coupled problem is established by considering heat and mass transfer and phase change for rock mass at low temperature, according to the theory of heat and mass transfer for porous media. It is considered of the influences of fluid transfer on the heat conduction and the temperature gradient on the seepage. By adopting the finite element method, the numerical simulation is done to study the range of frost-thaw of surrounding rock and the effects of insulation material in cold regions, which analysis the influence of tunnel depth and surrounding rock class on the range of frost-thaw, the change law of the frost-thaw area of different insulation material and the relationship between the frost-thaw area and the thickness of insulation material.

Scanning electron microscopy of the ventricular system in normal and hydrocephalic rabbits

1975 ◽  
Vol 42 (6) ◽  
pp. 646-664 ◽  
Author(s):  
Robert B. Page
Keyword(s):  
Silicone Oil ◽  
Third Ventricle ◽  
Ventricular Dilatation ◽  
Periventricular White Matter ◽  
Content Type ◽  
Morphological Alterations ◽  
Cell Processes ◽  
Fluid Transfer ◽  
Ependymal Lining ◽  
Scanning Electron

✓ The author used the scanning electron microscope to study the ependyma in six control rabbits and six rabbits made hydrocephalic by infusion of silicone oil into the cisterna magna. The ependymal lining of the third ventricle, head of the caudate nucleus, superior angle of the caudate, and atrium of the lateral ventricle was examined. In the hydrocephalic animals, clusters of cilia emanating from the ependyma over periventricular white matter become separated; the author believes this is secondary to ingrowth of new ependymal cell processes covered with microvilli. The addition of these cells to the ependymal surface permits ventricular dilatation without ependymal disruption and provides more surface containing microvilli, presumably capable of increased transventricular fluid transfer. No such changes occur over gray matter masses since their surfaces are not deformed by moderate ventricular dilatation. The morphological alterations in the ependyma that occur in moderate hydrocephalus do not appear to be simply manifestations of ependymal destruction but rather suggest a modification in its function from that of a surface capable of propelling cerebrospinal fluid to one capable of increased transfer of transventricular fluid. As hydrocephalus progresses, compensation may fail because of the relative decrease in microvilli so that the cell surface provides a less efficient mechanism for absorption.

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