The adenovirus major late transcription factor activates the rat gamma-fibrinogen promoter   总被引：45，自引：0，他引：45  

L A Chodosh  R W Carthew  J G Morgan  G R Crabtree  P A Sharp 《Science (New York, N.Y.)》1987,238(4827):684-688

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A new mechanism for the formation of meteoritic kerogen-like material     

Morgan WA  Feigelson ED  Wang H  Frenklach M 《Science (New York, N.Y.)》1991,252(5002):109-112

The carbon in ancient carbonaceous chondritic meteorites is mainly in a hydrocarbon composite similar to terrestrial kerogen, a cross-linked structure of aliphatic and aromatic hydrocarbons. Until recently, the composite has been commonly thought to have been produced in the early solar nebula by a Fischer-Tropsch-type process, involving the catalytic synthesis of hydrocarbons from carbon monoxide and hydrogen on grain surfaces. Instead, the aromatic hydrocarbons may form in gas-phase pyrolysis of simple aliphatics like acetylene and methane by a mechanism developed recently to explain formation of soot in combustion and of aromatic molecules in circumstellar envelopes. Nonequilibrium chemical kinetic calculations indicate that this mechanism can produce meteoritic aromatics if the initial concentration of simple hydrocarbons in the solar nebula was sufficiently but not unreasonably high.  相似文献   

Diagnostic ultrasound and sister chromatid exchanges: failure to reproduce positive findings     

V Ciaravino  A Brulfert  M W Miller  D Jacobson-Kram  W F Morgan 《Science (New York, N.Y.)》1985,227(4692):1349-1351

Human lymphocytes were exposed in vitro to ultrasound from two clinical devices, one of which was previously reported to have increased the frequency of sister chromatid exchanges. The ultrasonic exposures had no significant effect on the frequency of sister chromatid exchanges from three blood donors. Exposure to ultrasound also had no effect on cell cycle progression. A concomitant positive control (mitomycin C) resulted in a significant increase in sister chromatid exchanges.  相似文献   

( 3 H)lysergic acid diethylamide: cellular autoradiographic localization in rat brain   总被引：2，自引：0，他引：2  

I M Diab  D X Freedman  L J Roth 《Science (New York, N.Y.)》1971,173(4001):1022-1024

Intravenous administration of [(3)H]lysergic acid diethylamide(LSD) to rats resulted in accumulation of the drug in the brain within 15 minutes. Autoradiographic methods were used to differentiate free and bound [(3)H]LSD in brain tissue.Free [(3)H]LSD was generally distributed in the pituitary and pineal glands, cerebellum, hippocampus,and choroid plexus.Bound [(3)H]LSD was localized in neurons of the cortex, caudate nucleus, midbrain, and medulla,as well as in choroid plexus epithelium.  相似文献   

A Model for Agro-Economic Analysis of Soil pH Mapping     

Adamchuk  V. I.  Morgan  M. T.  Lowenberg-Deboer  James M. 《Precision Agriculture》2004,5(2):111-129

Core soil sampling followed by laboratory analysis is the traditional method used to map soil pH prior to variable rate application (VRA) of lime on cropland. A recently developed automated soil sampling system capable of measuring soil pH on-the-go has significantly increased sampling resolution. However, adoption of such systems must be justified economically. This paper presents a method for assessing the economic benefit from automated mapping of soil pH prior to variable rate lime application. In this work, geostatistical, agronomic, and economic methods were used to generate a comprehensive numerical model for quantitative assessment of the net return over cost of liming for different lime management strategies. The strategies included: automated pH mapping, manual grid soil sampling, and whole field sampling used in combination with either variable or fixed rate liming. The model was demonstrated using a simulated field with known average pH and semivariogram model. The analysis showed the largest benefit ($6.13ha^–1year^–1) from using VRA with automated soil pH mapping versus VRA based on 1ha (2.5acres) manual grid point sampling for the selected simulated field conditions. A sensitivity analysis demonstrated that for a wide range of field conditions and crop prices, VRA plus automated mapping promises higher relative benefits than VRA based on either manual grid point or grid cell sampling.  相似文献   

Individual tumors of multifocal EB virus-induced malignant lymphomas in tamarins arise from different B-cell clones   总被引：10，自引：0，他引：10  

M L Cleary  M A Epstein  S Finerty  R F Dorfman  G W Bornkamm  J K Kirkwood  A J Morgan  J Sklar 《Science (New York, N.Y.)》1985,228(4700):722-724

Cotton-top tamarins were inoculated with sufficient Epstein-Barr virus to induce multiple tumors in each animal within 14 to 21 days. The tumors consisted of large-cell lymphomas that contained multiple copies of the Epstein-Barr virus genome and generated Epstein-Barr virus-carrying cell lines showing no detectable consistent chromosomal abnormality. Hybridization of tumor DNA with immunoglobulin gene probes revealed that each lymphoma was oligo- or monoclonal in origin and that individual tumors from the same animal arose from different B-cell clones. Thus the virus induced multiple transformation events in tamarins in vivo to cause malignant tumors resembling the Epstein-Barr virus-associated lymphomas of patients with organ transplants.  相似文献   

Evidence for magnetospheric effects on the sodium atmosphere of mercury     

Potter AE  Morgan TH 《Science (New York, N.Y.)》1990,248(4957):835-838

Monochromatic images of Mercury at the sodium D(2) emission line showed excess sodium emission in localized regions at high northern and southern latitudes and day-to-day global variations in the distribution of sodium emission. These phenomena support the suggestion that magnetospheric effects could be the cause. Sputtering of surface minerals could produce sodium vapor in polar regions during magnetic substorms, when magnetospheric ions directly impact the surface. Another important process may be the transport of sodium ions along magnetic field lines toward polar regions, where they impact directly on the surface of Mercury and are neutralized to regenerate neutral sodium atoms. Day-to-day variations in planetary sodium distributions could result from changing solar activity, which can change the magnetosphere in time scales of a few hours. Observations of the sodium exosphere may provide a tool for remote monitoring of the magnetosphere of Mercury.  相似文献   

Cryopreservation, culture, and transplantation of human fetal mesencephalic tissue into monkeys     

D E Redmond  F Naftolin  T J Collier  C Leranth  R J Robbins  C D Sladek  R H Roth  J R Sladek 《Science (New York, N.Y.)》1988,242(4879):768-771

Studies in animals suggest that fetal neural grafts might restore lost neurological function in Parkinson's disease. In monkeys, such grafts survive for many months and reverse signs of parkinsonism, without attendant graft rejection. The successful and reliable application of a similar transplantation procedure to human patients, however, will require neural tissue obtained from human fetal cadavers, with demonstrated cellular identity, viability, and biological safety. In this report, human fetal neural tissue was successfully grafted into the brains of monkeys. Neural tissue was collected from human fetal cadavers after 9 to 12 weeks of gestation and cryopreserved in liquid nitrogen. Viability after up to 2 months of storage was demonstrated by cell culture and by transplantation into monkeys. Cryopreservation and storage of human fetal neural tissue would allow formation of a tissue bank. The stored cells could then be specifically tested to assure their cellular identity, viability, and bacteriological and virological safety before clinical use. The capacity to collect and maintain viable human fetal neural tissue would also facilitate research efforts to understand the development and function of the human brain and provide opportunities to study neurological diseases.  相似文献   

Cloned viral protein vaccine for foot-and-mouth disease: responses in cattle and swine   总被引：88，自引：0，他引：88  

D G Kleid  D Yansura  B Small  D Dowbenko  D M Moore  M J Grubman  P D McKercher  D O Morgan  B H Robertson  H L Bachrach 《Science (New York, N.Y.)》1981,214(4525):1125-1129

A DNA sequence coding for the immunogenic capsid protein VP3 of foot-and-mouth disease virus A12, prepared from the virion RNA, was ligated to a plasmid designed to express a chimeric protein from the Escherichia coli tryptophan promoter-operator system. When Escherichia coli transformed with this plasmid was grown in tryptophan-depleted media, approximately 17 percent of the total cellular protein was found to be an insoluble and stable chimeric protein. The purified chimeric protein competed equally on a molar basis with VP3 for specific antibodies to foot-and-mouth disease virus. When inoculated into six cattle and two swine, this protein elicited high levels of neutralizing antibody and protection against challenge with foot-and-mouth disease virus.  相似文献   

SOME SUGGESTIONS FOR NATIONAL SERVICE ON THE PART OF ZOOLOGISTS AND ZOOLOGICAL LABORATORIES     

Conklin EG  Forbes SA  Kofoid CA  Lillie FR  Morgan TH  Parker GH  Reighard J  Smith HM 《Science (New York, N.Y.)》1917,45(1173):627-630

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