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21.
Nico Vieweg Mehmet Ali Celik Sabine Zakel Vineet Gupta Gernot Frenking Martin Koch 《Journal of Infrared, Millimeter and Terahertz Waves》2014,35(5):478-485
We present the first systematic study of cyanobiphenyls (CBs) and the phenylcyclohexanes in the range between 50 cm-1 (1.5 THz) and 500 cm-1 (15 THz). The impact of the alkyl chain length and of variations in the core structure on the spectrum is investigated using liquid crystals from the cyanobiphenyl and phenylcyclohexane families. Our measurements are supported by calculations based on density functional theory. This enables us to shine light on the vibrational dynamics of liquid crystal molecules in the terahertz frequency range. 相似文献
22.
V. Vieweg 《Forschung im Ingenieurwesen》1930,1(3):101-105
Zusammenfassung Nach einer kurzen übersicht über die bisherigen Versuche zur Bestimmung der Schmierf?higkeit von ?len werden die in der Physikalisch-Technischen
Reichsanstalt zur Kl?rung des Schmiervorganges vorgenommenen Versuche besprochen. Es werden neue Verfahren zur Messung des
Verschlei?es mittels der Thermokraft des Lagers und zur Messung des von der Gleichrichterwirkung des Lagers herrührenden Orientierungseffektes
angegeben. Der Orientierungseffekt dient zur Kl?rung der Vorg?nge bei der Lagerschmierung, insbesondere der Grenzschmierung.
Nach gemeinsam mit J. Kluge in der Physikalisch-Technischen Reichsanstalt ausgeführten Versuchen
Vorgetragen in der Sitzung des Ausschusses 9—Schmiermittel—des Deutschen Verbandes für die Materialprüfungen der Technik am
10. Dezember 1929. 相似文献
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25.
TW Jones P Porter RS Sherwin EA Davis P O'Leary F Frazer G Byrne S Stick WV Tamborlane 《Canadian Metallurgical Quarterly》1998,338(23):1657-1662
BACKGROUND: In patients with type I diabetes mellitus, hypoglycemia occurs commonly during sleep and is frequently asymptomatic. This raises the question of whether sleep is associated with reduced counterregulatory-hormone responses to hypoglycemia. METHODS: We studied the counterregulatory-hormone responses to insulin-induced hypoglycemia in eight adolescent patients with type I diabetes and six age-matched normal subjects when they were awake during the day, asleep at night, and awake at night. In each study, the plasma glucose concentration was stabilized for 60 minutes at approximately 100 mg per deciliter (5.6 mmol per liter) and then reduced to 50 mg per deciliter (2.8 mmol per liter) and maintained at that concentration for 40 minutes. Plasma free insulin, epinephrine, norepinephrine, cortisol, and growth hormone were measured frequently during each study. Sleep was monitored by polysomnography. RESULTS: The plasma glucose and free insulin concentrations were similar in both groups during all studies. During the studies when the subjects were asleep, no one was awakened during the hypoglycemic phase, but during the final 30 minutes of the studies when the subjects were awake both the patients with diabetes and the normal subjects had symptoms of hypoglycemia. In the patients with diabetes, plasma epinephrine responses to hypoglycemia were blunted when they were asleep (mean [+/-SE] peak plasma epinephrine concentration, 70+/-14 pg per milliliter [382+/-76 pmol per liter]; P=0.3 for the comparison with base line), as compared with when they were awake during the day or night (238+/-39 pg per milliliter [1299+/-213 pmol per liter] P=0.004 for the comparison with base line, and 296+/-60 pg per milliliter [1616+/-327 pmol per liter], P=0.004, respectively). The patients' plasma norepinephrine responses were also reduced during sleep, whereas their plasma cortisol concentrations did not increase and their plasma growth hormone concentrations increased slightly. The patterns of counterregulatory-hormone responses in the normal subjects were similar. CONCLUSIONS: Sleep impairs counterregulatory-hormone responses to hypoglycemia in patients with diabetes and normal subjects. 相似文献
26.
The study aimed to evaluate the perception of discrimination in the Czech national HIV policy among gay men. The anonymous questionnaires were published in the gay journal and 191 respondents filled them and returned back. Their assessment of discrimination in the HIV policy and other life activities were ranked in 5-points scale. Assumed discrimination in the HIV policy was found to be one of the lowest one. Forty-one percent of men who answered did not find any discrimination in the HIV policy at all, eleven percent of them perceived it at the highest level. The personal perception of HIV discrimination was related to the fear of discrimination in the health facilities and to the general evaluation of political change for gay life. HIV policy is generally viewed as tolerant and without discriminative approach toward vulnerable minorities. The number of negative evaluations can play important role in the obstacles of preventive programs. 相似文献
27.
WV McCall 《Canadian Metallurgical Quarterly》1997,13(3):123-124
Although atrophie blanche is classified as a vasculitis, its presentation and management differ from the classical vasculitis. We present a patient with idiopathic atrophie blanche and discuss its management. 相似文献
28.
A dual direct/indirect room-sized calorimeter is used at the Beltsville Human Nutrition Research Center to measure heat emission and energy expenditure in humans. Because the response times of a gradient layer direct calorimeter and an indirect calorimeter are not equivalent, the respective rate of heat emission and energy expenditure cannot be directly compared. A system of equations has been developed and tested that can correct the respective outputs of the direct gradient layer calorimeter and indirect calorimeter for delays due to the response times of the measurement systems. Performance tests using alcohol combustion to simulate a human subject indicate accurate measurements of heat production from indirect (99.9 +/- 0.4%), indirect corrected for response time (99.9 +/- 0.5%), direct (99.9 +/- 0.8%), and direct corrected for response time (99.9 +/- 0.8%) calorimetry systems. Results from 24-h measurements in 10 subjects indicate that corrected heat emission is equivalent to (99.8 +/- 2.0%) corrected energy expenditure. However, heat emission measured during sleep was significantly greater (14%) than energy expenditure, suggesting a change in the energy stored as heat in the body. This difference was reversed during the day. These results illustrate how the simultaneous measurement of heat emission and energy expenditure provides insights into heat regulation. 相似文献
29.
In adult rodents, proliferating cells in the subventricular zone of lateral ventricle tangentially migrate into the olfactory bulb, where they become the interneurons. The present immunocytochemical analysis revealed that S100A6 (calcyclin), a specific calcium-binding protein of the S100 family, is restrictedly distributed in some astrocytes in the tangential migration pathway of the rat. These results suggest that a particular type of astrocytes containing S100A6 is associated with the tangential migration pathway. 相似文献
30.