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This article demonstrates experimental results of a thermal control system developed for ST-7 gravitational reference sensor (GRS) ground verification testing which provides thermal stability δT 24 hours. Continuing development of a model predictive feedforward control algorithm will extend performance to

We describe the calibration and operation of the ST7 GRS capacitive sensor system. A novel optical interferometer, featuring both fiber optic delivery and readout, is used for calibration of the capacitive sensor system and as a witness sensor during testing. The capacitive sensor showed 1 nm/√Hz performance from 1 mHz to 10 Hz. Above 10 mHz the optical system showed significantly better performance than the capacitive sensor, with a noise floor at 2 × 10−11 m/√Hz and a longer measurement standoff distance. The optical system was limited to 5 nm/√Hz at 1 mHz due to thermal disturbances of the laboratory environment, and could be reduced with a revised design and/or improved thermal stability.

Engineering model electrostatic sensing and forcing electronics developed for the LISA Pathfinder gravitational reference sensor (GRS) obtain measured displacement sensitivity δx ∼ 1.5×10−9 m Hz −1/2 to below f ⩽ 0.1×10−3 Hz with 30 Vdc fields when needed for proof‐mass initialization and charge measurement, while DC bias trim provides work‐function nulling to ± 50 mV with < 2mV step resolution and stability δV < 8×10−6 V Hz −1/2. Results are consistent with LISA noise models for electrostatic sensing, forcing, and DC nulling.

GABA level and the activity of l -glutamate-1-decarboxylase (GAD) (EC 4.1.1.15) were studied in brains of mice treated with β-vinyllactic acid, a new, selective and pyridoxal phosphate-independent GAD inhibitor. Valproate and diazepam protected mice against convulsions caused by β-vinyllactic acid although both anti-epileptic drugs antagonized neither the decrease in GABA concentrations nor the inhibition of GAD observed after treatment with β-vinyllactic acid alone. Assuming that the anticonvulsant effect measured with both antiepileptics is GABA mediated, these results support the hypothesis of a postsynaptic enhancement of GABAergic transmission by diazepam and valproate.

Microiontophoretically applied baclofen (B) potently depressed the majority of thalamic and neocortical neurons. A structure-activity study on the cell and reflex depressant action of a variety of B-derivatives was performed. Even small structural changes of the GABA-moiety were accompanied by significant reductions of the cell and reflex reducing action. These findings suggest that the activity of B does not reside only within the phenylethylamine moiety of B alone as suggested previously. In doses of 10 mg/kg IP B did not attenuate the cortically evoked excitations of striatal cells which are thought to be mediated through glutaminergic fibers. After systemic application we could demonstrate central effects at the single cellular level as well as by means of electroencephalographic investigations. In doses of 3–10 mg/kg IP B inhibits the spontaneous discharge rate of neurons in the dorsal raphe nucleus. In the freely moving cat 3.0 mg/kg PO B changed the sleep-waking pattern and high delta waves appeared on the EEG.

Fulvoplumierin (I) wurde durch partielle Hydrierung in Tetrahydro-fulvoplumierin (XXIII), in Hexahydro-fulvoplumierin (IV), in Iso-hexahydro-fulvoplumierin (XIX) und in das olige, nicht einheitliche Oktahydro-fulvoplumierin (XX) ubergefuhrt. Die Konstitution dieser Stoffe wurde aufgeklart. Ausgehend von IV und XXIII liess sich dann fur Fulvoplumierin selbst die Struktur I des 5′-Carbomethoxy-3′,4′; 1,2-cumalino-ω-propenyl-fulvens ableiten.

Die Konstitution des Visamminols (IV), eines optisch aktiven Chromons aus Ammi visnaga L., wurde durch verschiedene Abbaureaktionen aufgeklart. Die saurekatalysierte Wasserabspaltung lieferte das Furochromon Anhydrovisamminol (VIII), welches mit Lauge Aceton und 2-Isopropyl-4,6-dihydroxy-cumaron gab. Anhydrovisam- minol-methylather (IX) wurde zum 2-Isopropyl-4-methoxy-5-acetyl- 6-athoxy-cumaron abgebaut, das sich auch aus Visnagin bereiten liess. Durch Laugespaltung gefolgt von Methylierung entstand aus Visamminol (IV) (+)-2-Hydroxy-isopropyl-4,6-dimethoxy-cumaran, das sich auf Grund des IR.-Spektrums mit aus 2-γ,γ-Dimethylallyl-3, 5- dimethoxyphenol synthetisch bereitetem (±)-2-Hydroxyisopropyl-4, 6-dimethoxy-cumaran als identisch erwies. In Zusammenhang mit dieser Untersuchung wurden 2-Isopropyliden-4,6-dimethoxy-cumara- non-(3) - das mitt LiAlH4 oder NaBH4 nur 2-Isopropyl-4,6-di- methoxy-cumaranon-( 3 ) gab - und 2,2-Dimethyl-5,7-dimethoxy- chromen hergestellt.

The structure of Visamminol (I), a compound isolated fromAmmi visnaga bySmith, Pucci, andBywater, has been elucidated by degradation and by a comparison of the UV.-spectra of I and its derivatives with those of other chromones.

The visnagans fromAmmi visnaga L. and the stereoisomeric khellactones and methyl-khellactones derived from them were transformed into seselin and umbelli-ferone-8-aldehyde. These transformations and other degradations lead to revised formulas for these natural compounds.