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921.
A high incidence of prostate cancer was observed in some areas of Salamanca province, Spain. After excluding the most common etiological factors as the cause, it is concluded that the only possible risk factor must be due to the presence of some environmental carcinogen. In view of the etiological relationship between Cd and the pathological state, a study was carried out on the geochemistry of this element in the area. Anomalous amounts of Cd were found in stream sediments. This anomaly does not correspond to human activity, but rather to high regional amounts of cadmium in the substrate. Thus, the contents of Cd in soils developed over substrates containing naturally-occurring anomalous amounts of cadmium and the concentration in underground waters should be considered as a risk factor in this area. 相似文献
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925.
The aim of the present study was to determine the origin of the catecholaminergic inputs to the telencephalic basal ganglia of amphibians. For that purpose, retrograde tracing techniques were combined with tyrosine hydroxylase immunohistochemistry in the anurans Xenopus laevis and Rana perezi and the urodele Pleurodeles waltl. In all three species studied, a topographically organized dopaminergic projection was identified arising from the posterior tubercle/mesencephalic tegmentum and terminating in the striatum and the nucleus accumbens. Although essentially similar, the organization of the mesolimbic and mesostriatal connections in anurans seems to be more elaborate than in urodeles. The present study has also revealed the existence of a noradrenergic projection to the basal forebrain, which has its origin in the locus coeruleus. Additional catecholaminergic afferents to the striatum and the nucleus accumbens arise from the nucleus of the solitary tract, where catecholaminergic neurons appear to give rise to the bulk of the projections to the basal forebrain. In other regions, such as the olfactory bulb, the anterior preoptic area, the suprachiasmatic nucleus, and the thalamus, retrogradely labeled neurons (after basal forebrain tracer-applications) and catecholaminergic cells were intermingled, but none of these centers contained double-labeled cell bodies. It is concluded that the origin of the catecholaminergic innervation of the striatum and the nucleus accumbens in amphibians is largely comparable to that in amniotes. The present study, therefore, strongly supports the existence of a common pattern in the organization of the catecholaminergic inputs to the basal forebrain among tetrapod vertebrates. 相似文献
926.
J Schramlová K Blazek B Otová M Bartácková D Hulínská 《Canadian Metallurgical Quarterly》1997,43(5):195-199
The antiphlogistic Ibuprofen incorporated in liposomes caused a decrease of the inflammatory edema induced by Carrageenan in the distal part of the rat's hind leg after both the intramuscular and percutaneous administration. The antiphlogistic effect of free Ibuprofen in the cream was weaker. Intramuscular administration of empty liposomes slowed down in the initial stages the development of inflammation and slightly diminished the size of edema. 相似文献
927.
Mammalian mothers provide water to their young via milk. Rodent mothers reclaim much of this water by licking the anogenital areas of their pups, stimulating reflexive urination and consuming the pups' urine. Male rodents do not provide milk (hence water) to the young, but in some species male parents may nevertheless lick their pups. We determined the amount of water transfer from pups to mothers and fathers in the biparental California mouse, Peromyscus californicus, by injecting 5-, 10-, 20-, and 30-day-old pups with tritiated water and measuring the radioactive label in maternal and paternal plasma after 24 hrs of interaction with their litter. On Days 5 and 10, mothers obtained more pup urine than did fathers. Parents consumed equivalent amounts of pup urine on Days 20 and 30. Mothers engaged in more pup anogential licking than did fathers, which accounted for the difference in pup urine consumption. Salt appetite controls, in part, pup anogential licking in lactating rats (Gubernick & Alberts, 1983). Salt appetite was not implicated in the modulation of anogential licking in the California mouse because the mice failed to display a salt appetite. Licking of young and urine consumption are not dependent solely on the bidirectional exchange of water between the dam and her offspring. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
928.
A real-time interactive graphics simulation of the mechanics of the human thumb has been developed. The simulation utilizes a realistic data structure for the bones of the thumb which may be expanded to include the hand and forearm. This is coupled to a model of the kinematics of the joints in a concurrent processing arrangement in which the dynamic graphical transformations for scaling, translation, rotation, perspective, and clipping are all performed on a special-purpose display processor. The model and the control functions are distributed between this processor and a separate general-purpose superminicomputer. The resulting system presents the user with a realistic simulation of the movements of the thumb in normal and impaired states. The user may choose from a menu of options, including an interactive tendon transfer simulation for the current hand being simulated. He may control (interactively and in real time) the view, observation position, skeletal motion, and parameters for use in the model of joint mechanics. This type of computer modeling, utilizing a realistic three-dimensional data structure, models of musculoskeletal kinematics, and interactive programming, shows great potential for bringing mathematical modeling into useful clinical, research, and educational applications. 相似文献
929.
Chih-Chun Hsieh Tao-Chih Chang Dong-Yih Lin Ming-Che Chen Weite Wu 《Metals and Materials International》2007,13(5):411-416
The purpose of this study is to investigate the precipitation characteristics of σ phase in the fusion zone of stainless steel
welds at various welding passes during a tungsten are welding (GTAW) process. The morphology, quantity, and chemical composition
of the δ-ferrite and σ phase were analyzed using optical microscopy (OM), a ferritscope (FS), a X-ray diffractometer (XRD),
scanning electron microscopy (SEM), an electron probe micro-analyzer (EPMA), and a wavelength dispersive spectrometer (WDS),
respectively. Massive δ-ferrite was observed in the fusion zone of the first pass welds during welding of dissimilar stainless
steels. The σ phase precipitated at the inner δ-ferrite particles and decreased δ-ferrite content during the third pass welding.
The σ and δ phases can be stabilized by Si element, which promoted the phase transformation of σ→ϱ+λ2 in the fusion zone of the third pass welds. It was found that the σ phase was a Fe−Cr−Si intermetallic compound found in
the fusion zone of the third pass welds during multi-pass welding. 相似文献
930.
Six measures of divergent thinking were administered to 825 men ranging in age from 17 to 101 over the period from 1959 to 1972; repeat administrations were given to a subset of 278 men after a 6-year interval. Cross-sectional analyses showed curvilinear trends, with an increase in scores for men under 40 and a decline thereafter. Repeated measures analyses on subjects initially aged 33 to 74 generally replicated this finding, whereas cross-sequential analyses suggested a decline for all cohorts tested at a later time. Additional analyses suggested that not all of the decline could be attributed to reduced speed of response production. These longitudinal findings confirm earlier cross-sectional reports of decline in divergent thinking abilities with age. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献