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.     

A circular active reflector antenna (CARA), energy distribution calculations, and an experimental test

Conventional high-frequency (HF) circular phased arrays, such as the Wullenweber circular array, have a cost factor that increases at a greater-than-square law rate as its radius is increased to produce larger apertures. A new method of forming simultaneous beams in an HF circular array has been proposed in which beams are formed in the space within the array from pickup element energy that has been amplified and reradiated. Such a device is called a circular active reflector antenna (CARA), and its cost increases at a substantially linear rate as its radius is increased to form larger apertures. This paper describes calculations of the distribution of reradiated energy within such an array in order to study the effect of changes in array configuration. A cost analysis is presented to establish the dependence of array cost on array size for both the conventional and CARA types of arrays. In addition, the performance of an experimental CARA array is reported. An experimental CARA array consisting of a120degpartially filled sector of 1500 m radius, forming six beams over a2degfield of view was constructed at a site in Utah to demonstrate the feasibility of the concept. Measurements made on the experimental array showed that at 14-MHz, it formed beams0.7degwide at the 3-dB points, which agrees closely to the calculated value. The sidelobe response also compared closely to the level and angular position calculated for the sidelobes of the partially filled sector array tested. No evidence of instabilities or intermodulation distortion was noted.     

Performance of process schizophrenics on tasks involving visual search.

Compared the response times of 32 process schizophrenics and 16 nonhospitalized matched controls on 3 visual search tasks. Exp I involved the location of a target letter within an array of different background letters. Other experiments required a same–different response. Exp II involved the identification of a single different letter set within the uniform context of a square display formed by up to 40 replicates of another letter. Exp III presented 2 3–6 letter clusters in a single horizontal line. The 2 clusters were identical or had 1 different letter. Word and nonword clusters were used. Paranoid and nonparanoid groups did not differ on any measure. Schizophrenic response times were about 1 sec longer, but measures of rate of increase in response time with number of letters displayed did not generally differ significantly between groups. Schizophrenics tended to make more errors. Experimental manipulations affected the response times and error rates of schizophrenics and controls alike, and to much the same degree. Results suggest that process schizophrenics are not abnormally slow when extracting information from visual displays, and they appear to perform operations and strategies similar to those of normals when doing so. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of the thermal stabilities of a siloxane substituted polycarbonate with a standard polycarbonate and a polydimethylsiloxane

The thermal stability in inert and oxidising atmosphere of an aromatic polycarbonate with a siloxane side chain has been compared with those of a polycarbonate and a poly-(dimethylsiloxane) using thermogravimetry. The presence of the siloxane side chain is seen to marginally enhance the thermal stability compared to that of the unsubstituted polycarbonate.