Abstract: An instrument for detecting penetration of the epidural space comprises a barrel within which a plunger is urged forwardly by a resilient strap. The barrel has a nose on which a Tuohy needle is mounted. The inner surface of the barrel has a groove that extends along the barrel, being spaced from the nose. In operation the assembly is pushed forwardly until the tip of the needle contacts the spinal ligaments. The plunger is then pulled rearwardly past the end of the groove so that air enters the barrel and becomes trapped when the plunger is released and urged forwards by the strap. Penetration of the epidural space by the tip of the needle allows the trapped air to escape through the needle thereby providing an indication of penetration of the epidural space by causing the plunger to be moved forwards.

Abstract: Cellulose esters are cured by exposure to radiation preferably followed by exposure to elevated temperatures of at least about 100.degree. C. In addition, polymers obtained from reacting certain cellulose esters with certain polymerizable silicon esters are provided. The cured cellulose esters are suitable for producing transparent parts such as contact lenses.

Abstract: 2,2-Dimethyl-3,4-dihydro-2H-benzo[b]pyran-3-ols bearing an amino group in the 4-position and a cyano group in the benzo ring, their salts, esters and ethers, demonstrate excellent vasodilatory activity. The compounds, of which trans-2,2-dimethyl-4-isopropylamino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3 -ol is a representative embodiment, can be prepared from the corresponding 3,4-epoxy derivative upon treatment with an amine.

Abstract: Graphical data on a document is raster scanned and the resulting bit pattern is processed to provide a processed bit pattern which represents lines which each are a single pel in width and indicative of the shapes of objects scanned on the document. These single pel wide lines may represent the outlines of objects on the center lines. The processed bit pattern is then directed to a line follower in which bits representing contiguous pels are detected and tested for linearity. When contiguous pels fail the linearity test, a new vector is started and the vector being tracked is terminated. Hardware for performing these operations is described. The resulting vector list is stored until needed for display. Optionally a display station can be used to correct faulty vectors or to encode alphanumeric data in a more convenient format than vector coding.

Abstract: Compounds of the formula (I) ##STR1## and salts and pro-drugs thereof, wherein: R.sub.1 is a hydrogen atom or a lower alkyl group;R.sub.2 is a hydrogen atom or a lower alkyl group;R.sub.3 is a hydrogen atom or a lower alkyl group;R.sub.4 is a hydrogen atom or an alkyl group;R.sub.5 is a lower alkyl or a substituted alkyl group;or R.sub.4 and R.sub.5 are joined so that together with the nitrogen atom to which they are attached they form a 5-, 6- or 7-membered ring optionally containing an oxygen or sulphur atom;R.sub.6 is an electron donating group;R.sub.7 is an electron withdrawing group; andthe NR.sub.4 R.sub.5 and OR.sub.3 moieties are trans having compositions containing them and processes for their preparation.

Abstract: Compounds of the formula (I): ##STR1## and salts and pro-drugs thereof, wherein: R.sub.1 is a hydrogen atom or a lower alkyl group;R.sub.2 is a hydrogen atom or a lower alkyl group;R.sub.3 is a hydrogen atom or a lower alkyl group;R.sub.4 is a hydrogen atom or an alkyl group;R.sub.5 is a lower alkyl or a substituted alkyl group;or R.sub.4 and R.sub.5 are joined so that together with the nitrogen atom to which they are attached they form a 5-, 6- or 7-membered ring optionally containing an oxygen or sulphur atom;R.sub.6 is an electron donating group;R.sub.7 is an electron withdrawing group; andthe NR.sub.4 R.sub.5 and OR.sub.3 moieties are trans having antihypertensive activity, pharmaceutical compositions containing them and processes for their preparation.

Abstract: Compounds of the formula (I): ##STR1## wherein R.sub.1 and R.sub.2 are independently selected from a hydrogen atom and a C.sub.1-3 alkyl group;R.sub.3 is a hydrogen atom, a C.sub.1-3 alkyl or C.sub.2-4 acyl group;R.sub.4 is a hydrogen atom or C.sub.1-5 alkyl group;R.sub.5 is a C.sub.1-5 alkyl group, a straight chain C.sub.1-3 alkyl group terminally substituted by a chlorine atom;orR.sub.4 and R.sub.5 are joined so that together with the nitrogen atom to which they are attached they form a 5-, 6- or 7-membered ring optionally containing an oxygen or sulphur atom;R.sub.6 is a hydrogen atom, or a C.sub.1-5 alkyl, phenyl, CF.sub.3 or XH group wherein X is an oxygen or sulphur atom, the dotted line represents a bond, and R.sub.7 is not present; or R.sub.6 is an oxygen atom joined to the ring carbon atom by a double bond, the dotted line is not present, and R.sub.7 is hydrogen;the NR.sub.4 R.sub.5 and OR.sub.

Abstract: Amino chromanols, their preparation and anti-hypertensive compositions containing the compounds in hypotensive amounts with a pharmaceutically acceptable carrier for oral or parenteral administration. Pharmaceutically acceptable salts and O-acyl, particularly O-acetyl, derivatives are described. The compounds exist as racemates and optically active isomers.

Abstract: A system for tracking moving signal sources is disclosed which is particularly adaptable for use in tracking stage performers, although a wide range of other uses is possible. A miniature transmitter is attached to the person or object to be tracked and emits a detectable signal of a predetermined frequency. A plurality of detectors positioned in a preset pattern sense the signal and supply output information to a phase detector which applies signals representing the angular orientation of the transmitter to a computer. The computer provides command signals to a servo network which drives a device such as a motor driven mirror reflecting the beam of a spotlight, to track the moving transmitter.