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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water monitoring & remediation 16 (1996), S. 0 
    ISSN: 1745-6592
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Hydrologic investigations typically involve the collection of water level measurements at discrete points in space and time. The high cost of commercial electronic recorders can be a burden. We have developed an inexpensive (∼$200) electronic water level recorder consisting of a Motorola microcontroller, a clock, memory, pressure transducers, and associated circuitry. The instrument is powered by a 6-V battery. These devices, each capable of monitoring up to eight channels of analog input, are presently providing continuous monitoring of nested piezometers, tide gauges, and rain gauges in hydrologic studies at the Savannah River site and the North Inlet (South Carolina) Long-Term Ecological Research (LTER) site. The instruments can be custom tailored to record water levels at any specified time interval, or whenever the water level changes by a specified amount, and can store up to 32,000 water level observations. These instruments have been used to conduct slug tests and can be configured to monitor observation wells for pumping tests. Simplicity of construction and availability of components offer hydrologists an inexpensive but reliable method of water level recording. Several examples of the use of this instrumentation in diverse hydrologic settings are described.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 81 (2002), S. 803-805 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have demonstrated comprehensive electric field tuning of the Rabi splitting between the excitonic and photonic modes of a superlattice-embedded microcavity. Using photocurrent spectroscopy to measure the coupling between the modes, we have tuned the microcavity to the maximum possible splitting. We have observed a marked increase in the splitting from 4.5 to 11.5 meV, due to the electric-field enhancement of the superlattice exciton's oscillator strength and the oscillator strength's subsequent decrease due to the quantum confined Stark effect. As well, we have determined the oscillator strength for the exciton, finding good agreement with theoretical and experimental values. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 36 (1981), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The content and fatty acid composition of cholesterol esters of the human brain during development from 13 weeks' gestation up to 26 months of age was studied. The three major brain areas, the forebrain, cerebellum, and the brain stem, were studied separately. The concentration of the esters in each brain region was the highest at the earliest fetal age of 13 weeks and fell during growth. However, transient rises in the concentration were observed, at about birth in the forebrain and at 4–5 months after birth in the cerebellum The peak concentration during the transient period (125–150 μg/g fresh tissue of forebrain and 100–125 μg/g of cerebellum) was similar to the concentrations observed in the two parts respectively during early fetal ages. The brain stem also showed similar transient peak at about a few weeks before birth, but only when the esters were expressed as amount per cell. In absolute terms, a clear transient period was evident in the forebrain between birth and 9 months, while in the cerebellum or the brain stem, the total amount of the esters increased up to about 1 year of age and then remained almost unchanged. The major fatty acids of the esters were palmitic, palmitoleic, stearic, oleic, linoleic and arachidonic acid. Most of these fatty acids showed certain changes in relative proportions during development. Thus, in the forebrain, palmitic and oleic acid decreased from about 32% and 40% (weight percentages) at 13–15 weeks of gestation to about 20% and 25% respectively at 26 months of age. During this period, linoleic and arachidonic acid increased from about 3% and S% to about 10% and 24%, respectively. Most of these changes occurred after birth. The cerebellum and the brain stem differed only slightly from the forebrain in either the fatty acid composition or the pattern of the developmental changes in the composition.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 25 (1975), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —Male Wistar rats aged 24 days were divided into three groups. Two groups were given a high protein (250 g/kg casein) and a low protein (30 g/kg casein) diet respectively. The third group was given an amount of the high protein diet containing the same amount of energy as that consumed by the low protein diet rats. The plasma of the animals on low protein contained 20% of the concentration of tryptophan of animals on the other two diets. In these animals the concentration of tryptophan was reduced in the forebrain, cerebellum and brain stem, and the concentrations of 5-HT and 5-hydroxyindoleacetic acid were reduced in the forebrain and brain stem. The low protein diet decreased the total uptake of l-[G-3H]tryptophan into the brain and its incorporation into brain protein. Plasma insulin concentrations were reduced in the low protein and ‘restricted high protein’ animals and the plasma corticosterone concentration was raised in the low protein animals. Exogenous insulin did not raise the plasma tryptophan concentration in the low protein animals but it increased the uptake of l-[G-3H]tryptophan into the brain and its incorporation into protein. Rehabilitation for 7 days restored the plasma and brain tryptophan concentrations and those of brain 5-HT and 5-hydroxyindoleacetic acid to control values.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 20 (1973), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The ganglioside content of the forebrain, brain stem and cerebellum have been studied, in the rat at various ages from 1 day to 27 months, and in the pig at various ages from 93 days gestation to 30 months. Each part of the brain was analysed for total ganglioside NANA and for four major gangliosides (GMl, GD1a, GDlb and GT1 in the nomenclature of Svennerholm, 1963). In the rat forebrain, the concentration of ganglioside NANA rose rapidly between 1 and 21 days after birth, fell to 3 months and subsequently rose to a mature value at 6 months. In the rat cerebellum, the peak concentration was reached at 2 months and the lower adult value at 9 months, whilst in the brain stern, the concentration rose more slowly and had a broad peak from 15 days to 2 months. Values are also given for the changes in the total amounts in each brain part. The changes in the concentrations and total amounts of ganglioside NANA, in the three parts of the pig brain were, on the whole, similar to those in rat brain except that the percentage distribution of the major gangliosides had almost attained the mature pattern at birth. In the forebrain of both species, the disialoganglioside, GD1a, accounted for the highest percentage of the total gangliosides. The results are discussed with respect to their possible structural significance.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 33 (1979), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 28 (1977), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The phospholipid content and composition of the different regions of the developing human brain were studied. Brains from 25 fetuses and 9 infants, aged 13 weeks gestation to 26 months, were analysed. The concentration of total lipid-P was highest in the brain stem and lowest in the cerebellum at any age. Compared with the forebrain or brain stem, the cerebellum had a sharp phospholipid growth spurt between 3 months before and 6 months after birth. Before birth, the phospholipid pattern was similar in each part of the brain, with choline phosphoglycerides as the major phospholipid. After birth, the pattern in the brain stem changed further and ethanolamine phosphoglycerides became the dominant phospholipid, while in the other two there was little change. In all parts of the brain the proportion of sphingomyelin increased. The relative proportion of serine and inositol phosphoglycerides remained almost constant throughout the whole period of development. The possible significances of the changes in the phospholipids in neurological development are discussed.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 28 (1977), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The ganglioside content and composition of brains from twenty-five human fetuses, three new-born babies and ten children, were studied. The ages ranged from 13 weeks gestation to 26 months postpartum. Each brain was divided into forebrain. cerebellum and brain stem. The concentration of total gangliosides rose to a plateau at different stages of development in the different parts, whereas the total amount reached a constant value at 9 months of age in each part. The developmental profile of individual gangliosides differed in the different parts of the brain. Thus, in the forebrain GD1a. and in the cerebellum GD1a rose to become the major gangliosides. The brain stem showed little change in its ganglioside pattern during the developmental period studied. The possible significance of these charges in the gangliosides during development is discussed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 28 (1977), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The concentrations of the polyamines and putrescine were measured in the brains of human infants during fetal and early postnatal development. The concentrations of the amines were also measured in the brains of children who were malnourished during the first 2 years of life. In the brains of the adequately-nourished infants there were differences in the developmental profiles of the amines between different regions of the brain, and the changes in polyamine concentrations paralleled changes in nucleic acid accumulation. The concentration of putrescine was much higher than that of the polyamines in all regions of the brain, and in the brain stem there were marked increases in putrescine concentration at the time of most rapid rate of myelination. Putrescine also increased markedly in the forebrain at the time of neuroblast multiplication in the fetus. In children malnourished during the first year of life there were reductions in the concentrations of spermidine and putrescine in the forebrain and brainstem, but spermine was unaffected. Malnutrition had no effect on the concentration of any of the amines in the cerebellum.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry 16 (1924), S. 1013-1015 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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