Summary The spatial organization and laminar distribution of projections from the olfactory bulb and the anterior (PPCa) and posterior (PPCp) divisions of the prepiriform cortex to the entorhinal cortex were studied with anterograde (3H-leucine) and retrograde (WGA-HRP) tracing techniques. After 3H-leucine injections into the olfactory bulb transported labeling was seen over the lateral entorhinal area, except its most medial part, and over the rostral part of the medial entorhinal area. The labeling covers exclusively layer Ia. The lateral and medial entorhinal areas are also reached by fibers from the prepiriform cortex. The projection to the medial entorhinal area has not been described previously. Following injections of 3H-leucine into the PPCa transported labeling is present over the entire expanse of the entorhinal cortex and is located over layer Ib with the greatest density in its superficial part. Injections of 3H-leucine into the PPCp give rise to transported labeling over much of the entorhinal cortex. No labeling was found over the most medial parts of the medial subdivision (VMEA) of the lateral entorhinal area and the medial entorhinal area. Labeling occupies layer Ib, especially its middle part, and layers II and III. Both PPCa and PPCp appear to project most heavily to the dorsal (DLEA) and ventral (VLEA) subdivisions of the lateral entorhinal area. From the retrograde experiments it can be inferred that cells of layers II and III of the PPCa project predominantly to the DLEA, whereas those of the PPCp project predominantly to the VLEA. The MEA receives its heaviest projection from layer II of both PPCa and PPCp. In control experiments with 3H-leucine injections into the endopiriform nucleus it was found that this nucleus projects to the entire expanse of the entorhinal cortex. The fibers distribute to all layers with the exception of layer Ia.Abbreviations AI
agranular insular cortex
- AL
lateral nucleus of the amygdala
- BL
basolateral nucleus of the amygdala
- BM
basomedial nucleus of the amygdala
- C
claustrum
- CoA
cortical nucleus of the amygdala
- DLEA
dorsal division of the lateral entorhinal cortex
- END
endopiriform nucleus
- H
hippocampus
- I
granular insular cortex
- lot
lateral olfactory tractus
- MCL
mitral cell layer of the olfactory bulb
- MEA
medial entorhinal area
- OB
olfactory bulb
- PPCa
anterior part of the prepiriform nucleus
- PPCp
posterior part of the prepiriform nucleus
- VLEA
ventral division of the lateral entorhinal cortex
- VMEA
ventromedial division of the lateral entorhinal cortex
- 35
area 35 of the perirhinal cortex
- 36
area 36 of the perirhinal cortex 相似文献
Summary An analysis of autopsy data shows that during the period 1928–1972 the relative frequency of carcinoma of the stomach has remained practically unchanged. A similar trend is apparant from the mortality statistics for Vienna from 1955 to 1972. Whereas for the lower and middle age groups there is a real decrease during the period 1928–1952, an opposite trend is visible for the highest age group. The stomach and the lower parts of the large intestine are the most frequent sites of carcinoma of the alimentary canal. The frequency distribution is explained on the basis of the contact hypothesis. 相似文献
The effect of temperature and sex on spatial distribution ofDrosophila melanogaster adults was studied in a specially designed apparatus. It was observed that individuals tend to aggregate in sections of the sphere independently of sex and temperature. Nevertheless, decrease in temperature increase aggregation. The mobility of both males and females indicates a megative geotactic tendency. 相似文献
Summary: Bis(phenoxy‐imine) Zr complexes with MAO activation can produce polyethylenes with well‐defined bimodal molecular weight distributions. Polymerization behavior indicates that minor changes in the ligand structures can have a significant effect on the modality of the resulting polyethylenes. Although there is no direct relationship between the bimodal catalytic behavior and the structure of a precatalyst complex in solution, a precatalyst complex having a methyl or methoxy group para to the phenoxy‐oxygen inclined to exhibit bimodal behavior whereas that with a pentafluorophenyl group on the imine‐nitrogen displayed unimodal behavior. Polymerization results suggest that bimodal behavior is linked to the presence of two kinds of cationic active species, which arise from different modes of ligand coordination. A qualitative correlation was found between the calculated amounts of possible cationic active species and the uni‐ and bimodal catalytic behavior. Based on the results obtained, we concluded that the bimodal polyethylenes are produced by two kinds of cationic active species having two available cis‐located sites with cis‐N, trans‐O and cis‐N, cis‐O arrangements. The results introduced herein are rare examples of the production of well‐defined bimodal polyethylenes using a single precatalyst.
Bis(phenoxy imine) Zr complexes can produce well‐defined bimodal polyethylenes. 相似文献
Vestibular functions are known to show some deterioration with age. Vestibular deterioration is often thought to be compensated
for by an increase in neck proprioceptive gain. We studied this presumed compensatory mechanism by measuring psychophysical
responses to vestibular (horizontal canal), neck and combined stimuli in 50 healthy human subjects as a function of age (range
15–76 years). After passive horizontal rotations of head and/or trunk (torso) in complete darkness (dominant frequencies 0.05,
0.1, and 0.4 Hz), subjects readjusted a visual target to its remembered prerotational location in space. (1) Vestibular-only stimulus (whole-body rotation); subjects' responses were shifted towards postrotatory body position, this only slightly at 0.4 Hz and
pronounced at 0.1 and 0.05 Hz. These errors reflect the known physiological drop of vestibular gain at low rotational frequency.
They exhibited a slight but significant increase with age. (2) Neck-only stimulus (trunk rotated, head stationary); the responses showed errors similar to those upon vestibular stimulation (with offset towards
postrotatory trunk position) and this again slightly more with increasing age. (3) Vestibular-neck stimulus combination during head rotation on stationary trunk; the errors were close to zero, independent of stimulus frequency and the subjects'
age. (4) Opposite stimulus combination (trunk rotated in the same direction as the head, but with double amplitude); the errors were clearly enhanced, essentially
reflecting the sum of those with vestibular-only and neck-only stimulation. Taken together, we find a parallel increase in
neck- and vestibular-related errors with age, in seeming contrast to previous studies. We explain our and the previous findings
by a vestibular-neck interaction model in which two different neck signals are involved. One neck signal is used, in combination
with the vestibular signal, for estimating trunk-in-space rotation. It is internally shaped to always match the vestibular
signal, so that these two signals cancel each other out when summed during head rotation on stationary trunk. Because of this
matching, perceived trunk stationariness during head rotation on the stationary trunk is independent of vestibular deterioration
(related to stimulus frequency, age, ototoxic medication, etc.). The other neck proprioceptive signal, coding head-on-trunk
rotation, is superimposed on the estimate of trunk-in-space rotation, thereby yielding a notion of head-in-space. This neck
signal remains essentially unchanged with vestibular deterioration. Generally, we hold that the transformation of the vestibular
signal from the head down to the trunk proceeds further to include the hip and the legs as well as the haptically perceived
body support surface; by this, subjects yield a notion of support kinematics in space. As a consequence, spatial orientation
is impaired by chronic vestibular deterioration only to the extent that the body support is moving in space, while it is unimpaired
(determined by proprioception alone) during body motion with respect to a stationary support.
Electronic Publication 相似文献
Summary: The polycondensation of 1‐ethynyl‐2,5‐dihexyl‐4‐iodobenzene in the presence of 1‐ethynyl‐2,5‐dihexyl‐4‐(2‐phenylethynyl)benzene proceeds according to the mechanism of initiated chain growth polycondensation. It has allowed the synthesis of oligomers with a desired molecular weight and a narrow molecular weight distribution. The reasons for the side reaction leading to the formation of diyne compounds are revealed and the presumed mechanism is given. This opens prospects for the preparation of defectless poly(p‐phenyleneethynylene)s with required molecular weights and narrow molecular weight distributions.
Summary The spines of apical dendrites of the layer V pyramidal cells of the area striata in the mouse represent a sequence of post-synaptic structures receiving a variety of contacts from terminal fibers derived fundamentally from short axon cells and superficial pyramidal cells. The study of Golgi preparations of mice 180 days old shows the existence of the most complicated terminal structures over portions of apical dendrites at the levels of layers III and IV. Observations on young mice reveals the terminations of the specific afferent fibers on the dendrites of short axon cells. A mathematical model which defines the distribution of spines along the apical dendrites is introduced. The principal equation of the model has been adjusted from the data processing of microscope countings through a series of programs written for an IBM 7070. The equation defines satisfactorily the different distributions of dendritic spines in mice 10–180 days old raised in normal conditions and in complete darkness. The equation defines also the distribution of dendritic spines in the visual cortex of mice enucleated at birth on one side, and the distribution along the apical dendrites of various cortical areas of the hamster, cat and man. The number of dendritic spines increases with the age of the subject and their distribution varies significantly according to the values of the parameters of the model. 相似文献
To investigate the relation between donor characteristics and TRALI incidence.
Background
Transfusion-related acute lung injury (TRALI) is a potentially fatal complication of transfusion. In pre-clinical studies and several clinical studies, TRALI has been related to loss of product quality during red blood cell (RBC) storage, called the “storage lesion”. Donor characteristics, as for example age, genetics and life style choices influence this “storage lesion”. We hypothesized that donor sex, age and blood type is related to TRALI incidence.
Methods/materials
We performed a secondary analysis of two cohort studies, designed to identify TRALI risk factors by matching TRALI patients to transfused controls. We obtained donor sex, age and blood type from the Dutch Blood Bank Sanquin and investigated TRALI incidence in patients who were exposed to a certain donor characteristic. We used Kruskal-Wallis testing to compare the number of transfused products and Chi2 testing to compare proportions of TRALI patients and transfused control.
Results
After implementation of the male-donor only plasma strategy, patients received more transfusion products from male donors. However, we did not detect a relation between TRALI incidence and donor sex. Both TRALI patients and transfused controls received mainly products from donors over 41 years old, but donor age did not influence TRALI risk. Donor blood type, the transfusion of blood type-compatible and blood type-matched products also had no influence on TRALI incidence.
Conclusion
We conclude that in two cohorts of TRALI patients, donor age, donor sex and donor blood type are unrelated to TRALI. 相似文献