摘要:
In a short total synthesis of morphinan compounds, derivatives of 1-benzyl-1,2,3,4-tetrahydroisoquinoline are produced. Certain of these compounds, although highly aromatic and functionalized, can be optically resolved. The optically active enantiomers can serve as important intermediates for both natural and unnatural opioids.
摘要:
A nondenaturing zwitterionic detergent for proteins which, for example, consists of an effective amount of 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). This detergent is of extreme interest in the biological study of proteins due to its nondenaturing characteristic. Other examples of the group may be prepared from different alicyclic compounds, for example, utilizing cholic acid and in others deoxycholic acid and dehydroabietic acid. A process for the preparation of these compounds starts with cholic or the equivalent and from this is prepared the triethylammonium salt in tetradhydrofuran (THF). After the salt is completely dissolved in THF, ethyl chloroformate is added and the flask cooled to 0 C. Then the mixed anhydride which forms is reacted with dimethylaminopropylamine to form the dimethylaminopropyl derivative of a carboxylic acid amide. Finally, the tertiary amine group is reacted with propanesultone to give the sulfobetaine product. An improved procedure for preparation of these compounds and especially for the last step (as for CHAPSO) to react the N-(3-dimethylaminopropyl) cholamide with sodium-1-chloro-2-hydroxy-3-propanesulfonate.
摘要:
The use of a catalytic coating (7, 7', 7'') which acts to combine both the heat source and heat-transfer mechanism for a working fluid, such as that used in an external combustion engine (1). Maximum heat exchange is accomplished by the direct bonding of the coating (7, 7', 7'') per se, to the engine head with a compound of catalytic agents which confines heat of combustion directly thereto. The preferred embodiment of the engine head surface may be finned or otherwise enlarged to provide for an increased surface area necessary for the heating of the engine head. This means of surface combustion results in a highly fuel-efficient engine and/or heat source with very low exhaust pollutants.
摘要:
Long term closed chest partial and total cardiopulmonary bypass by peripheral cannulation for severe right and/or left ventricular failure is achieved by the use of a percutaneous coil (10, 100, 200, 300) positioned in the pulmonary artery (22) across the pulmonary artery valve (22) to decompress the left heart by keeping the pulmonary artery valve (22) open during cardiopulmonary bypass.
摘要:
Tightly focused beams of laser light are used as 'optical tweezers' to trap and manipulate polarizable objects such as microspheres of glass or latex with diameters on the order of 4.5 νm. When analytes are allowed to adhere to the microspheres, small quantities of these analytes can be manipulated, thus allowing their detection and quantitation even when amounts and concentrations of the analytes are extremely small. Illustrative examples include measuring the strength needed to break antibody-antigen bonds and the detection of DNA sequences.