Abstract:
A tridentate conjugate has three chemical moieties, or tridentate members, attached through an appropriate spacer moiety. At least two of the tridentate members are relatively small molecules, usually less than about 7,000 Daltons in size. The particular appropriate spacer moiety selected for a tridentate imparts certain steric properties to the tridentate conjugate. In one embodiment, the binding of a macromolecular specific binding partner to one of the tridentate members sterically inhibits the binding of a different macromolecule to another tridentate member. In another embodiment, the binding of a first tridentate member to a macromolecule restricts the subsequent binding of a second tridentate member to a proximate location on the same macromolecule.
Abstract:
A method for perforating a sheet material provides for a perforating die located intermediate two orbital rollers. The two orbital rollers move in orbital paths in the same orbital direction at the same speed and in positions which are 180 degrees apart. Each roller acts as a temporary storage input and output in opposite phase from each other so that incoming sheet material is alternately stored and dispensed as a loop on the orbital roller. Since the rollers are out of phase, this permits a segment of the sheet material to be stopped intermediate the orbital rollers so that the perforating die can act on the stopped segment.
Abstract:
Apparatus for measuring carbon dioxide and chloride in blood. A blood sample is reacted with acid in a sample container to release carbon dioxide, a portion of which diffuses through a gas-permeable membrane and reacts with an electrolyte to change the pH thereof. A pair of pH measuring electrodes monitor the electrolyte pH at respective locations adjacent to and remote from the region of reaction within the electrolyte. The pH electrodes are coupled to respective input terminals of a differential amplifier to derive a differential pH signal. The differential pH signal is differentiated to derive a rate of change of pH output signal which is measured to indicate the concentration of carbon dioxide. The pH measuring electrodes are in electrolytic communication and means is provided to renew the electrolyte between measurements. Coulometric measurement of chloride in the sample is performed simultaneously with the carbon dioxide measurement.
Abstract:
AN APPARATUS FOR BATCH ANALYSIS OF LIQUID SAMPLES WHEREIN SYRINGES ARE EMPLOED FOR DELIVERING REPEATABLE VOLUMES OF REAGENT TO A CELL PRIOR TO THE ADDITION OF A SAMPLE AND FOR WITHDRAWING LIQUID FROM THE CELLA AFTER ANALYSIS THEREOF. SENSING MEANS, SUCH AS A POLAROGRAPHIC OXYGEN SENSOR, IS MOUNTED IN THE SIDE WALL OF THE CELL WITH ITS SENSING CONTACTING THE LIQUID THEREIN. A STIRRING ELEMENT IS POSITIONED WITHIN THE CELL AND ROTATED ABOUT THE VERTICAL AXIS OF THE CELL SO THAT A HIGH TANGENTIAL STIRRING FORCE IS PRODUCED TO PROMOTE MIXING OF SAMPLE WITH REAGENT AND TO OPTIMIZE SENSOR PERFORMANCE, YET ONLY SMALL SAMPLE VOLUMES ARE REQUIRED. THE APPARATUS IS PARTICULARLY SUITED FOR RATE SENSING BATCH ANALYSIS OF BIOLOGICAL FLUIDS SUCH AS BLOOD OR URINE.