Determination of oxyethylene distribution in condensates of primary alcohols with ethylene oxide

A new method has been developed that makes possible determination of the oxyethylene distribution of the condensates of mixed carbon number detergent-range, primary alcohols with ethylene oxide over a wide range. Circular thin layer chromatography of the 3,5-dinitrobenzoate ester derivatives is used to separate the condensates into a series of groups, each group containing all of the compounds present having the same number of oxyethylene units. These groups of esters are recovered and determined by a spectrophotometric procedure. Distribution curves are obtained that cover the range of added oxyethylene units from 0 to as high as 18. Higher adducts are recovered and determined as a group. Presented at the AOCS Meeting in New York, October, 1968.     

Grids for Assessing Colour Appearance

A technique of subjective magnitude estimation has been used to assess a set of pseudosurface colours, each having a luminance equal to half that of its adapting surround. Five observers scaled each of the colours three times in each of two adaptation conditions corresponding to daylight and tungsten light at 120 cd/m². Loci of constant hue and saturation were derived in u', v' chromaticity space for daylight and tungsten light. These grids enable the appearance of a colour to be specified from a knowledge of its chromaticity coordinates and they enable such effects as colour constancy and colour fidelity to be investigated in terms of perceived colour appearance.     

Biosynthesis and subcellular localization of histamine in H-110 lymphoma

The histidine decarboxylase activity has been studied in the H-110 Lymphoma implanted in Balb-c mice. The enzymatic activity has been determined using DL-Histidine 1-14C by measuring the I--14CO2 liberated during the incubation. It has been found that the histidine decarboxylase activity in the tumor is the highest of the studied tissues. The pretreatment for 5 days with two cytostatic drugs, cyclophosphamide and 5-fluoruracile, determined a decrease of the enzymatic activity in the tumor of 33 and 54 per cent, respectively. This effect has not been observed in the lung. The pretreatment of the animals during 10 days with 0.1 mg per kg body of histamine, which in other experimental tumors induces an increase of the endogenous content of histamine, produces a decrease of the tumoral histidine decarboxylase activity. The histamine-14C uptake was not modified by this pretreatment. The subcellular localization of the radioactivity after pretreatment with histamine-14C evidenced that the nuclear fraction of the tumor contained between 2 and 10 times the radioactivity of other tissues of the same animal.     

Neural dynamics of planned arm movements: Emergent invariants and speed-accuracy properties during trajectory formation.

A real-time neural network model, called the vector-integration-to-endpoint (VITE) model is developed and used to simulate quantitatively behavioral and neural data about planned and passive arm movements. Invariants of arm movements emerge through network interactions rather than through an explicitly precomputed trajectory. Quantitative simulations are provided of Woodworth's law, of the speed–accuracy trade-off known as Fitts's law, of isotonic arm-movement properties before and after deafferentation, of synchronous and compensatory "central-error-correction" properties of isometric contractions, of velocity amplification during target switching, of velocity profile invariance and asymmetry, of the changes in velocity profile asymmetry at higher movement speeds, of the automatic compensation for staggered onset times of synergetic muscles, of vector cell properties in precentral motor cortex, of the inverse relation between movement duration and peak velocity, and of peak acceleration as a function of movement amplitude and duration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)