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Biomedical subjects

R Lenke

Publications and source records attributed to R Lenke.

12 recordsLinked to original sources
PubMed2004

Record high extreme-ultraviolet efficiency at near-normal incidence from a multilayer-coated polymer-overcoated blazed ion-etched holographic grating.

We have measured the extreme-ultraviolet (EUV) efficiency of a polymer-overcoated blazed ion-etched holographic test grating. The grating had a magnetron-sputtered Mo2C/Si multilayer coating matched to the grating blaze angle of 2.78 degrees. At an angle of incidence of 5.6 degrees and a wavelength of 15.79 nm, the measured efficiency peaks in the second outside order at 29.9%. The derived groove efficiency is 53.0%. To the best of our knowledge these are the highest values obtained yet at EUV wavelengths from a holographic ion-etched blazed grating.

Journal Article↗
PubMed1988

Hormonal control of sleep-appetitive behaviour and diurnal activity rhythms in the cleaner wrasse Labroides dimidiatus (Labridae, Teleostei).

In its natural environment the cleaner wrasse, Labroides dimidiatus, possesses a hiding place in the reef, where it disappears every night. In my experiments, the Labroides was offered a specific sleeping cave in tanks. Photocells at the entrance to each cave, connected to a printer, counted the sleep-appetitive behaviour (SAB), viz. the investigation of the sleeping-place. Untreated animals visited the cave 45.6 times within 90 min prior to darkness. The swimming activity, which was measured 3 times daily, declined in the course of the light period. During the night the animals are totally motionless. Four substances which are involved in the sleep-influencing processes in mammals were tested. Injection of the neurotransmitter serotonin (0.05-0.5 micrograms/g b.wt. 5-HT) resulted in a decrease of swimming activity and SAB; the 5-HT blocking substance p-chlorophenylalanine (1-8 micrograms/g b.wt. PCPA) intensified this activity and suppressed SAB only in a concentration-range of 10 and 12 micrograms/g b.wt. In addition, the neuromodulatory properties of vasoactive intestinal polypeptide (VIP) and arginine vasotocin (AVT) were investigated. It is noteworthy to mention that VIP (1-1.5 micrograms/g b.wt.) lead to an remarkable increase, and AVT (0.5-4 micrograms/g b.wt.) to a significant reduction of the SAB.

Animals↗
PubMed1981

Amniocentesis in the second trimester: the effect on fetal movement.

Linear array real-time ultrasound was utilized to observe gross fetal body movements before and after second-trimester amniocentesis. No significant differences were found between the two observation periods. All pregnancies continued to term, and no evidence of fetal trauma was found at delivery.

Amniocentesis↗