Early axon outgrowth of retinal ganglion cells in the fetal rhesus macaque

Employing retinal explants and retrograde transport techniques, we studied the formation of the arcuate fascicles by examining the growth of the central retina, the emergence of the adult fiber layer pattern, and the projections of retinal ganglion cells in the central and peripheral retina. Sixty days prior to foveal pit formation, the distance from the incipient fovea to the optic disk was equal to the adult, even though the retinal area was only 8% of the adult. Arcuate fibers, at this age, were observed to avoid the incipient fovea, with no fascicles and few axons projecting over this region. A small population of 15.2% of the ganglion cells located within 2 mm of the incipient fovea possessed an axon with an aberrant trajectory that wound around and projected 50 to several hundred microns away from the optic disk, compared to only 3% at other retinal locations. The incidence of disorder decreased with increasing fetal age, establishing mature values in late fetal periods. These findings suggest that the area of the central retina does not increase after embryonic day 60 and that guidance factors are present that allow outgrowing ganglion cell axons to distinguish and avoid that portion of the retina that will become the fovea.     

Epitope mapping of the major inner capsid protein of group A rotavirus using peptide synthesis

Nucleic acid amplification by polymerase chain reaction (PCR) is a very powerful technique in terms of sensitivity but is limited in terms of ability to perform accurate quantitation. While there is a theoretical correlation between copies of input target sequence and those of PCR product, the quantitative nature of this relationship is obscured by unpredictable variations in reaction conditions and by inhibitory and/or stimulatory substances which might be present in sample preparations, especially those derived from biological fluids. To reliably estimate copies of input DNA target from PCR product, we designed a combination of internal and external control systems coupled to DNA/RNA hybridization and enzymatic immunodetection techniques. The internal control system served to monitor amplification efficiency and to correct for the effects of inhibitors or stimuli on the efficiency of the DNA amplification. The assay is quantitative, nonisotopic, and can be widely applied to assessment of the quantity of DNA present in a wide range of preparations.     

The physics of mechanical alloying: A first report

In this paper, we present a first attempt to define the basic geometry, mechanics, and physics of the process of mechanical alloying. The geometry of the collision events which lead to particle fragmentation and coalescence is modeled on the basis of Hertzian contacts between the grinding media which entrap a certain amount of material volume between the impacting surfaces. This geometry essentially defines the volume of material affected per collision, and from this information and characteristics of the specific mill and the material being processed, impact times, powder strain rates and strains, powder temperature increase, powder cooling times, and milling times can be approximated.     

Effects of systemic atropine sulfate administration on the frequency content of the cat sensorimotor EEG during sleep and waking.

Sensorimotor electroencephalogram (EEG) frequencies in cats were evaluated with power spectral analysis before and after 3 doses of atropine sulfate. All doses of atropine tested caused enhanced EEG slow waves (0–7 Hz) and spindles (8–25 Hz) during waking immobility, and postdrug frequency profiles during slow-wave sleep and waking immobility were identical. With 0.75 mg/kg atropine, movement (head movement, locomotion) resulted in EEG desynchronization and reduced power in all frequencies less than 24 Hz. After 1.5 or 3.0 mg/kg atropine, power in low frequencies remained elevated during movement, but power in spindle frequencies was significantly reduced compared with other states. During active REM sleep after 1.5 mg/kg atropine, power in spindle frequencies was significantly lower than that during quiet REM sleep. These results indicate that the sensorimotor cortical EEG in cats is under the control of multiple systems. At least 1 of these systems is active during movement, and its actions are resistant to muscarinic receptor blockade. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A cognitive approach to intelligence: Attention, coding and planning.

Reviews the progress of the planning-attention-simultaneous-successive (PASS) theory, described by J. P. Dass (1972, 1973). The theory describes behavior as the result of the interdependent functioning of planning, attention (arousal), and coding (either simultaneous or successive) systems. Most research conducted to 1979 concerned simultaneous and successive coding in working memory and relied on principle components analyses. Research since 1980 has examined the roles of arousal, especially in attention, and of the planning system; experimental studies and confirmatory analyses have also been conducted. Relationships of PASS theory to other theories and approaches are considered. Three areas of application are examined: understanding achievement skills and learning problems, theory-based assessment of cognitive processes, and instructional design. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Teaching Morse-Code reception with signals weighted in frequency according to their difficulty.

An experimental group (N = 19) was trained to receive Morse code with signals that were weighted with respect to frequency of presentation in rough proportion to their order of difficulty for beginners. A control group (N = 19), matched on a code aptitude test performance, was trained with each signal presented an equal number of times. On the test runs, no significant differences were observed in the progress of the two groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gram-negative anaerobic bacilli: Their role in infection and patterns of susceptibility to antimicrobial agents. II. Little-known Fusobacterium species and miscellaneous genera

Twenty infrequently reported species of gram-negative anaerobic bacilli other than Fusobacterium nucleatum, Fusobacterium necrophorum, and members of the genus Bacteroides were studied with regard to their role in infection and their susceptibility to antimicrobial agents. In addition, the literature regarding the recovery of these organisms from both the normal flora and infections of humans was reviewed. During a six-year period at the Wadsworth Clinical Anaerobic Bacteriology Research Laboratory (Veterans Administration Wadsworth Medical Center, Los Angeles, Calif.), 39 (6%) of 679 specimens obtained from anaerobic infections yielded "other gram-negative anaerobic bacilli" (OGNAB). Fusobacterium naviforme, Fusobacterium gonidiaformans, Fusobacterium varium, Fusobacterium mortiferum, and Fusobacterium russii were the most commonly isolated OGNAB. Most of the OGNAB tested were resistant to erythromycin, and most strains, except for F. varium, were susceptible to beta-lactam antibiotics and clindamycin. Chloramphenicol and metronidazole were active against all strains of OGNAB tested. Certain Fusobacterium species are undoubtedly previously unrecognized members of the normal flora of the oropharynx, upper respiratory tract, or urogenital tract and may be present in infections derived from these floras.     

Ethnic stereotypes: The significance of consensus.

Investigated whether the degree of consensus in trait attribution to ethnic groups has any particular meaning to the individual. Canadian 9th and 12th graders (n = 36) were presented with traits previously found in the stereotypes about different groups, and asked to identify the ethnic group so characterized. 3 independent variables were manipulated: consensus of the attributes, age of the Ss, and the number of attributes presented. Dependent variables included the accuracy and the perceived difficulty of identification. Results indicate that the degree of consensus in the stereotype had considerable information value to the Ss. This suggests that stereotypes generally develop from information available to a community, and that the consensus noted in stereotype assessment procedures reflects the consistency of this information. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constancy of psychotic syndromes in men and women.

Interview behavior ratings were obtained on the Inpatient Multidimensional Psychiatric Scale for 375 male and 448 female psychotics from 16 state and university hospitals. An hypothesis-testing factor analysis confirmed 11 of the 12 factors (syndromes) hypothesized. The congruency coefficients indicated essential constancy between men and women across the 11 syndromes established. 4 similar 2nd order factors accounted for the correlations among the factor scores in both groups. Comparisons of the 2 sexes as to score level revealed that the males were more retarded, while the females were more excited. Thus, men and women are quite similar as to the kinds of psychotic behaviors they exhibit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)