Molecular-beam epitaxy-grown Si whisker structures: morphological, optical and electrical properties.

Scanning electron microscopy, spectroscopic ellipsometry, and current-voltage and current-temperature measurements were employed to characterize nanowhisker structures grown by molecular-beam epitaxy on Si(111) substrates. Small clusters of gold deposited on the Si surface were used as the seeds for nanowhisker growth. The diameter of grown nanowhiskers and their length ranged from 70 to 200 nm and from 580 to 890 nm, respectively. The whiskers were found to inherit the (111) orientation of the Si substrate. By means of spectroscopic ellipsometry in the range 1.5-4.77 eV, lateral optical inhomogeneity of the nanowhisker layer was revealed, with optical properties of the layer substantially differing from those of single-crystal Si. Electrical measurements point to the presence of a Schottky barrier with height 0.70 eV in the structure and to the presence of electrically active centers non-uniformly distributed over the nanowhisker length.

[Effects of low-intensity electromagnetic irradiation and endogenous peptides on isolated neurons of Helix lucorum]. / Vliianie élektromagnitnogo izlucheniia (3 GGts) nizkoi intensivnosti i éndogennykh peptidov na izolirovannye neirony vinogradnoi ulitki.

In experiments with isolated neurones of molluscan Helix lucorum the effects of low intensity electromagnetic fields (EMF) and endogenous peptides on the transmembrane current dynamics was studied. A certain relationship between peptides and EMF effects was shown. Some features of primary mechanisms of EMF biological action were clarified.

[Changes in the chemosensitive properties of the central neurons of the snail Helix pomatia and of the mouse as affected by opioid peptides]. / Izmenenie khemosensitivnykh svoistv tsentral'nykh neironov ulitki Helix pomatia i myshi pod vliianiem opioidnykh peptidov.

In experiments on neurones of the isolated ganglia of the snail and surviving hippocampal slices from mice, studies have been made of the effect of Met- and Leu-enkephalins on neuronal sensitivity to acetylcholine and norepinephrine. It was shown that in some cases the enkephalins do not affect bioelectrical activity of the neurones, but changed their responses to acetylcholine and norepinephrine. It is concluded that during investigation of the effect of enkephalins on the nervous cells, alongside with changes in the bioelectrical activity, special attention should be paid to changes in chemoreceptive properties of the neurones.

[Steroid-sensitive neurons of the rabbit and mouse hippocampus]. / Steroidochuvstvitel'nye neirony gippokampa krolika i myshi.

On the whole brain of rabbits and surviving slices of the hippocamp of mice, studies have been made of the sensitivity and peculiarities of the reaction of hippocampal neurones to hydrocortison administration. In experiments on whole animals, the drug was applied to the hippocampal neurones by means of microionophoretic technique. In experiments with slices, the steroid hormone was injected with a special micropipette directly in to the chamber with the slice. It was shown that there are many nervous cells in the hippocamp which are sensitive to corticosteroids. Possible role of steroid hormones in neurochemical mechanisms of the hippocamp is discussed.

[Comparative sensitivity of surviving sections of hippocampus to corticosteroids and angiotensin II]. / Sravnitel'naia chuvstvitel'nost' neironov perezhivaiushchikh srezov gippokampa k kortikosteroidam i angiotenzinu II.

Sensitivity of CA3 field neurones to hydrocortisone hemisuccinate, sodium dexamethasone-21-phosphate and angiotensin II was studied in experiments on surviving sections of the mouse hippocampus. High sensitivity of the neurones of surviving sections of the hippocampus to the steroid hormones (hydrocortisone and dexamethasone) and virtually complete absence of responses to angiotensin II were demonstrated.

[Effect of cyclic 3',5'-adenosine monophosphate on central neurons]. / O deistvii tsiklicheskogo 3',5'-adenozinmonofosfata na tsentral'nye neirony.

In experiments on unanesthetized non-immobilized rabbits, unit responses in the cortex and thalamus to the cyclic 3',5'-adenosine monophosphate (cAMPh) were studied by means of microionophoresis. It was shown that cAMPh changes the pattern of background unit activity, increasing or decreasing the discharge frequency. cAMPh changes unit responses both to acetylcholine and noradrenaline. These data permit, to assume that cAMPh participates both in adrenergic and in acetylocholinergic mechanisms of excitation processing in brain neurones.