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21.
M. Rerez-Reyes Martha C. Timmons M. A. Lipton H. D. Christensen K. H. Davis M. E. Wall 《Cellular and molecular life sciences : CMLS》1973,29(8):1009-1010
Resumen Se hizo un estudio comparativo de la capacidad del 9-tetrahidro-cannabinol y de sus metabolitos monohidroxilados en producir effectos similares a los de la marihuana cuando son inyectados intravenosamente a humanos. Se encontro que la hidroxilacion en la posición 11 no cambio la potencia, en la posición 8 la redujo, y en la posición 8 la abolio por completo.
These studies were conducted under Contract No. HSM-42-71-95 between the Center for Studies of Narcotic and Drug Abuse of the Division of Narcotic Addition and Drug Abuse, NIMH, and the Research Triangle Institute. In addition, this investigation was supported by Public Health service Research Grant No. RR-46 from the General Clinical Research Centers Branch of the Division of Research Resources. We thank Drs.Monique Braude and st.Szara, Center for Studies of Narcotic and Drug Abuse, NIMH, for their interest and encouragement of this program. We also thankCarolyn Bishop andDaynise Skeen for their technical assistance. 相似文献
These studies were conducted under Contract No. HSM-42-71-95 between the Center for Studies of Narcotic and Drug Abuse of the Division of Narcotic Addition and Drug Abuse, NIMH, and the Research Triangle Institute. In addition, this investigation was supported by Public Health service Research Grant No. RR-46 from the General Clinical Research Centers Branch of the Division of Research Resources. We thank Drs.Monique Braude and st.Szara, Center for Studies of Narcotic and Drug Abuse, NIMH, for their interest and encouragement of this program. We also thankCarolyn Bishop andDaynise Skeen for their technical assistance. 相似文献
22.
Squyres SW Aharonson O Arvidson RE Bell JF Christensen PR Clark BC Crisp JA Farrand W Glotch T Golombek MP Grant J Grotzinger J Herkenhoff KE Johnson JR Jolliff BL Knoll AH McLennan SM McSween HY Moore JM Rice JW Tosca N 《Nature》2006,443(7107):E1-2; discussion E2
The Mars Exploration Rover Opportunity discovered sulphate-rich sedimentary rocks at Meridiani Planum on Mars, which are interpreted by McCollom and Hynek as altered volcanic rocks. However, their conclusions are derived from an incorrect representation of our depositional model, which is upheld by more recent Rover data. We contend that all the available data still support an aeolian and aqueous sedimentary origin for Meridiani bedrock. 相似文献
23.
为通过模型分析和模拟来制定控制杂草的优化策略,我们设计并完成了一个杂草种子风扩散的室内实验。本文根据实验获得的数据建立了杂草种子扩散的空间模型。结果表明:杂草种子在任意方向上的扩散服从近似的高斯分布;在实验条件下,杂草种子扩散的空间分布型随风速的变化而变化。著名的Howard等〔5〕的杂草扩散模型是本文所建模型的特例。据此,我们推断Howard等〔5〕的模型所表示的分布型与一定高度的杂草种子在中等风速条件下扩散的分布型相似。 相似文献
24.
Syncytin is involved in breast cancer-endothelial cell fusions 总被引:2,自引:0,他引:2
Bjerregaard B Holck S Christensen IJ Larsson LI 《Cellular and molecular life sciences : CMLS》2006,63(16):1906-1911
Cancer cells can fuse spontaneously with normal host cells, including endothelial cells, and such fusions may strongly modulate
the biological behaviour of tumors. However, the underlying mechanisms are unknown. We now show that human breast cancer cell
lines and 63 out of 165 (38%) breast cancer specimens express syncytin, an endogenous retroviral envelope protein, previously
implicated in fusions between placental trophoblast cells. Additionally, endothelial and cancer cells are shown to express
ASCT-2, a receptor for syncytin. Syncytin antisense treatment decreases syncytin expression and inhibits fusions between breast
cancer cells and endothelial cells. Moreover, a syncytin inhibitory peptide also inhibits fusions between cancer and endothelial
cells. These results are the first to show that syncytin is expressed by human cancer cells and is involved in cancer-endothelial
cell fusions.
Received 2 May 2006; received after revision 7 June 2006; accepted 12 June 2006 相似文献
25.
Although pinyon-juniper woodland is common throughout most of Utah, it is less so in Utah and Salt Lake valleys. Even so, stands do occur in the valleys and are known to have been there since presettlement times. Three such stands occurring along the eastern sections of the valleys have shown major decreases in area since settlement times, and one has all but disappeared. Their disappearance is attributed to early use for fuel, agricultural, and urbanization purposes. 相似文献
26.
The putative oncogene GASC1 demethylates tri- and dimethylated lysine 9 on histone H3 总被引:1,自引:0,他引:1
Cloos PA Christensen J Agger K Maiolica A Rappsilber J Antal T Hansen KH Helin K 《Nature》2006,442(7100):307-311
27.
Christensen PR 《Nature》2003,422(6927):45-48
The observation of gullies on Mars indicates the presence of liquid water near the surface in recent times, which is difficult to reconcile with the current cold climate. Gullies have been proposed to form through surface runoff from subsurface aquifers or through melting of near-surface ice under warmer conditions. But these gullies are observed to occur preferentially in cold mid-latitudes, where the presence of liquid water is less likely, and on isolated surfaces where groundwater seepage would not be expected, making both potential explanations unsatisfactory. Here I show that gullies can form by the melting of water-rich snow that has been transported from the poles to mid-latitudes during periods of high obliquity within the past 10(5) to 10(6) years (refs 5, 6). Melting within this snow can generate sufficient water to erode gullies in about 5,000 years. My proposed model for gully formation is consistent with the age and location of the gullies, and it explains the occurrence of liquid water in the cold mid-latitudes as well as on isolated surfaces. Remnants of the snowpacks are still present on mid-latitude, pole-facing slopes, and the recent or current occurrence of liquid water within them provides a potential abode for life. 相似文献
28.
Climate modelling: Severe summertime flooding in Europe 总被引:13,自引:0,他引:13
29.
Finger-length ratios and sexual orientation 总被引:1,自引:0,他引:1
Williams TJ Pepitone ME Christensen SE Cooke BM Huberman AD Breedlove NJ Breedlove TJ Jordan CL Breedlove SM 《Nature》2000,404(6777):455-456
30.
Assessment of Mars Exploration Rover landing site predictions 总被引:1,自引:0,他引:1
Golombek MP Arvidson RE Bell JF Christensen PR Crisp JA Crumpler LS Ehlmann BL Fergason RL Grant JA Greeley R Haldemann AF Kass DM Parker TJ Schofield JT Squyres SW Zurek RW 《Nature》2005,436(7047):44-48
Comprehensive analyses of remote sensing data during the three-year effort to select the Mars Exploration Rover landing sites at Gusev crater and at Meridiani Planum correctly predicted the atmospheric density profile during entry and descent and the safe and trafficable surfaces explored by the two rovers. The Gusev crater site was correctly predicted to be a low-relief surface that was less rocky than the Viking landing sites but comparably dusty. A dark, low-albedo, flat plain composed of basaltic sand and haematite with very few rocks was expected and found at Meridiani Planum. These results argue that future efforts to select safe landing sites based on existing and acquired remote sensing data will be successful. In contrast, geological interpretations of the sites based on remote sensing data were less certain and less successful, which emphasizes the inherent ambiguities in understanding surface geology from remotely sensed data and the uncertainty in predicting exactly what materials will be available for study at a landing site. 相似文献