EXACT MIMICRY OF NONLINEAR OSCILLATORY POTENTIAL MOTION: NONUNIQUENESS OF ISODYNAMICAL TRACTS

1997 ◽  
Vol 204 (3) ◽  
pp. 519-532 ◽  
Author(s):  
H.P.W. Gottlieb
1979 ◽  
Vol 178 (4) ◽  
pp. 220-225 ◽  
Author(s):  
Supachui Chotibutr ◽  
Mikio Miyata ◽  
Hiroko Hirosawa ◽  
Satoshi Ishikawa

Toxicology ◽  
1994 ◽  
Vol 93 (2-3) ◽  
pp. 113-124 ◽  
Author(s):  
Charles D. Garner ◽  
Eun Woo Lee

2018 ◽  
Vol 21 (5) ◽  
pp. 356-363
Author(s):  
Ekaterina M. Klochihina ◽  
Aleksey K. Erdyakov ◽  
Maria P. Morozova ◽  
Svetlana A. Gavrilova ◽  
Elena S. Akhapkina ◽  
...  

Objectives: Diabetic retinopathy remains the major cause of blindness among the working-age population of developed countries. Considering this, experimental models of diabetes involving laboratory animals are important for assessing clinically significant methods to determine early pathologic alterations of the retina. The early detection of diabetic retinopathy in combination with a search for new pathogenetic targets will enable focusing on new strategies to limit the development of critical changes in the retina and to prolong retinal functioning during the development of diabetes mellitus. Aim: This study aimed to define parameters of electroretinography test that identifies changes due to retinal impairment in diabetes. Methods: Experimental diabetes was induced in Wistar rats by intraperitoneally injecting streptozocin (65 mg/kg; group DM). The control group (CB) received intraperitoneal injections of the vehicle, i.e. citric buffer. On each consecutive day of the experiment, all rats received insulin detemir (2 u/kg). Ophthalmoscopy and electroretinography were conducted before initiating the experiment and after 50, 58 and 66 days of injectin sptreptozocin. Results: Amid 2u\kg insulin injection the glucose level in venous blood in DM group amounted to 30-40 mM. The ophthalmoscopy showed that the optic nerve disk paled by the 50th day, with its line erasing. During electroretinography, wave amplitude in oscillatory potential test tended to decrease. -wave latency of photopic system increased with -wave latency of photopic system and - and -waves latency of scotopic system not altering. In addition, the amplitude of rhythmic stimulation of 8 and 12 Hz decreased. Conclusion: The most apparent parameters of electroretinography for modelling streptozocin-induced diabetes are wave amplitude during the oscillatory potential test, photopic B-wave latency and the amplitude of rhythmic stimulation. These results suggest that in diabetes, ischaemic injury is an important cause of early dysfunction of inner retinal layers.


1993 ◽  
Vol 252 ◽  
pp. 565-584 ◽  
Author(s):  
Victor I. Shrira

We consider a classic boundary-value problem for deep-water gravity-capillary waves in a shear flow, composed of the Rayleigh equation and the standard linearized kinematic and dynamic inviscid boundary conditions at the free surface. We derived the exact solution for this problem in terms of an infinite series in powers of a certain parameter e, which characterizes the smallness of the deviation of the wave motion from the potential motion. For the existence and absolute convergence of the solution it is sufficient that e be less than unity.The truncated sums of the series provide approximate solutions with a priori prescribed accuracy. In particular, for the short-wave instability, which can be interpreted as the Miles critical-layer-type instability, the explicit approximate expressions for the growth rates are derived. The growth rates in a certain (very narrow) range of scales can exceed the Miles increments caused by the wind.The effect of thin boundary layers on the dispersion relation was also investigated using an asymptotic procedure based on the smallness of the product of the layer thickness and wavenumber. The criterion specifying when and with what accuracy the boundary-layer influence can be neglected has been derived.


1956 ◽  
Vol 186 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Carlo A. Terzuolo ◽  
Bo E. Gernandt

Single unit activity during convulsive synchronized discharge and the relationship between unit activity and slow ‘waves’ were studied in the spinal cord of the decerebrate cat after intravenous injection of strychnine. Steel needle microelectrodes were used. Units did discharge in burst (from 1 to 5 impulses) only in coincidence with the slow oscillatory potential (tetanic ‘waves’). The firing is confined to the rising phase of this potential. Changes in d.c. state related to a convulsive activity were also studied. A relationship was found between frequency of the tetanic rhythm and d.c. state of spinal structures. The mechanisms of synchronization and rhythmicity of the convulsive activity in a population of neurons are discussed in connection with the problem of interaction between units.


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