Crystal structure of a silyl cation with no coordination to anion and distant coordination to solvent     

Lambert JB  Zhang S  Stern CL  Huffman JC 《Science (New York, N.Y.)》1993,260(5116):1917-1918

The crystal structure of a stable silyl cation, triethylsilylium, in the form of its tetrakis (pentafluorophenyl)borate salt [Et(3)Si(+) (C(6)F(5))(4)B(-)] (Et, ethyl) shows no coordination between cation and anion. The closest silicon-fluorine distance is greater than 4 angstroms. A toluene solvent molecule is close enough to cause some deviations from planarity at the silicon, but the silicon-toluene distance is well beyond the sum of the silicon and carbon covalent radii. The toluene molecule is essentially planar and undistorted, as expected if little or no positive charge has been transferred from silicon to toluene.  相似文献   

Control of carcinogenesis: a possible role for the activated macrophage   总被引：20，自引：0，他引：20  

J B Hibbs  L H Lambert  J S Remington 《Science (New York, N.Y.)》1972,177(53):998-1000

Cytotoxic activity of activated mouse macrophages against mouse embryo fibroblasts was tested before and after spontaneous transformation of the fibroblasts in vitro. Activated macrophages caused little or no destruction of untransformed fibroblasts but were markedly cytotoxic to the same fibroblasts after spontaneous transformation. The efferent limb of this cytotoxic reaction appears to be nonimmunologic and to be related to abnormal growth properties rather than to the antigenic composition of target cells.  相似文献   

Stratospheric Nitric Oxide: Measurements during Daytime and Sunset     

Burkhardt EG  Lambert CA  Patel CK 《Science (New York, N.Y.)》1975,188(4193):1111-1113

Measurements of the temporal variation in the stratospheric nitric oxide concentration covering a time period from 11:00 to 20:30 local time show the effect of solar ultraviolet sunset. The experimental results strongly support the theorized role of nitric oxide as a catalyst in the destruction of ozone and its importance in the stratospheric ozone balance.  相似文献   

MATHEMATICS AND GEOPHYSICS     

Lambert WD 《Science (New York, N.Y.)》1924,59(1515):30-32

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Bottom currents in the hudson canyon     

Keller GH  Lambert D  Rowe G  Staresinic N 《Science (New York, N.Y.)》1973,180(4082):181-183

In-place measurements of the bottom currents in the Hudson Canyon reveal that the current regime is characterized by a pronounced reversal of flow up and down the canyon. Velocities are commonly of the order of 8 to 15 centimeters per second, reaching 27 centimeters per second on occasion in the upper and central portion of the canyon. Although alpha 2.5-day recording of currents showed a net transport upcanyon, a combination of 66 current measurements from the submersible Alvin, the analysis of sediment texture and organic carbon, and the determination of the benthic fauna-nutrient relationship indicate that over the long term there is a net transport of fine material through the canyon to the outer continenital rise.  相似文献   

Reeves kingpin: A high-yielding mid-season potato variety suitable for fry processing     

Z. N. Ganga  G. A. Porter  D. H. Lambert  G. Sewell  A. Bushway  B. de los Reyes 《American Journal of Potato Research》2006,83(2):141-147

Reeves Kingpin is a mid-season processing potato variety developed and selected at the University of Maine’s Aroostook Research Farm in Presque Isle, Maine. Its main attribute is its high-yielding potential, giving an average yield of 47 mt/ha. Reeves Kingpin is suitable for processing into french fries due to its large tubers, high specific gravity, and acceptable fry color. The average specific gravity of Reeves Kingpin is 1.085 which is comparable or better than ‘Russet Burbank’ and ‘Shepody’. Reeves Kingpin has received good baking scores, which may qualify it for fresh market; however, its tuber appearance generally does not meet fresh market standard. The tubers have netted to lightly russeted skin and are long and blocky in shape. The tubers rarely exhibit the pointed and knobby characteristics of Russet Burbank. The incidence of misshapen tubers, sunburn, and growth cracks can be high under some conditions; however, hollow heart, internal heat necrosis, and vascular discoloration are not usually a problem. Tubers of Reeves Kingpin are relatively tolerant to shatter and black spot bruise. The plants of Reeves Kingpin are relatively taller, with greener leaves, more flowers, and moderate to heavy fruit set compared to Russet Burbank. The late-season vigor of Reeves Kingpin is an advantage compared to Shepody, but its haulms can be hard to kill prior to harvest, particularly if over-fertilized. Reeves Kingpin is resistant to tuber net necrosis and moderately resistant to verticillium wilt and early blight. However, it is susceptible to golden cyst nematode, late blight, bacterial ring rot, and corky ring spot virus and moderately susceptible to common scab.  相似文献   

Low-income consumers' attitudes and behaviour towards access,availability and motivation to eat fruit and vegetables     

Dibsdall LA  Lambert N  Bobbin RF  Frewer LJ 《Public health nutrition》2003,6(2):159-168

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Nutritional interactions influencing diseases of potato     

D. H. Lambert  M. L. Powelson  W. R. Stevenson 《American Journal of Potato Research》2005,82(4):309-319

Nutrient management can decrease the severity of a number of important potato diseases, and certain practices, such as maintaining a low pH for scab control, have been followed for that single objective. More commonly, growers have incorporated fertility modifications into their particular disease and farming situations. Unfortunately, disease minimization may or may not be consistent with optimal fertilization for yield, quality, and profitability. Optimization for one disease may not match that for another, and the exact mechanisms involved are often complex and poorly understood. Potato growers will continue to experience conflicting production constraints. These constraints include price-driven needs for yield improvement and expense reduction; customer-driven demands for quality improvement; varietal shifts driven by the above considerations rather than by disease reduction; increasing pressure to justify, shift and reduce pesticide use; continuing concerns about nitrogen and phosphorus movement in groundwater and runoff; and increased attention to management of rotation crops. On the positive side, nutrient management strategies for highly specific situations continue to improve and practices addressing nutrient and disease variability within fields are becoming more sophisticated. In this context, there are opportunities for cultural management practices that reduce disease pressure and reliance on chemical controls. To be effectively integrated into such specialized management systems, the mechanisms of these control measures and the conditions under which they are practical will need to be better understood. Likewise, disease responses to these tactics need to be better quantified to allow an adequate cost-benefit analysis. With mounting concerns about the effects of agricultural pesticides on food safety, farm workers, and the environment, management of plant-available nutrients may become practical approaches for disease suppression in the future.  相似文献   

Monticello: A mid-season variety with good tuber appearance and chipping potential from mid-to long-term storage     

G. A. Porter  D. H. Lambert  A. A. Bushway  R. L. Plaisted  K. M. Paddock  W. S. DeJong  D. E. Halseth 《American Journal of Potato Research》2004,81(2):143-152

Monticello (NY102), a new medium-maturing, roundwhite chipping variety was released in 2003 by the University of Maine and Cornell University. It is primarily intended for use in the chipping industry, especially from mid-to long-term storage. Its ability to chip from relatively long-term storage, low storage weight loss, and relatively long tuber dormancy should be particularly valuable. Tubers have shown a good ability to recondition and regain good chip color after periods of stress in storage. Monticello’s specific gravity typically averages only a few points lower than Atlantic, a variety that is widely used for out-of-field chipping in the eastern U.S. Chip color of Monticello has been very good from short-, mid-, and long-term storage. It has been grown successfully in commercial-scale tests in Maine since 1999 with combined seed and chipping production of more than 37 and 60 ha during 2001 and 2002, respectively. Research and commercial-scale trials in Maine have generally produced favorable yield and quality results relative to other storage chippers like Snowden. The tubers are bright and attractive with relatively few external defects. Tuber size tends to be fairly small and is ideal for chipping. Sensory panel tests have also shown that Monticello is good for boiling and baking. Although ideally suited for chipping, the fresh market may serve as a secondary market for this variety because of its typically good external appearance and cooking quality scores. Monticello has moderate to good common scab resistance and is resistant to golden nematode. It is moderately susceptible to blackspot bruise, powdery scab, and typical foliar diseases of potato. Although tubers can develop hollow heart and internal heat necrosis, Monticello is typically much less susceptible than Atlantic.  相似文献   

Streptolysin-O/antibiotics adjunct therapy modulates site-specific expression of extracellular matrix and inflammatory genes in lungs of Rhodococcus equi infected foals     

Volkan Gurel  Kristyn Lambert  Allen E. Page  Alan T. Loynachan  Katherine Huges  John F. Timoney  Michael Fettinger  David W. Horohov  John McMichael 《Veterinary research communications》2013,37(2):145-154

The addition of streptolysin-O (SLO) to the standard antibiotics regimen was shown to be superior to antibiotics alone after experimental infection of foals with Rhodoccocus equi (R. equi). The objective of this study is to investigate this response by determining the site-specific expression of extracellular matrix (ECM) and inflammatory response genes in biopsy samples taken from three distinct lung regions of the infected foals. Twenty-four foals were challenged by intrabronchial instillation of R. equi and assigned to four treatment groups: SLO/antibiotics adjunct therapy, antibiotics-only therapy (7.5 mg/kg clarithromycin and 5 mg/kg rifampin), SLO-only, and saline-only treatments. Treatments were administered twice daily for 16 days unless symptoms progressed to the point where the foals needed to be euthanized. Gene expressions were determined using custom-designed equine real-time qPCR arrays containing forty-eight genes from ECM remodeling and inflammation pathways. A non-parametric Wilcoxon signed-rank test for independent samples was applied to two pairs of time-matched comparison groups, SLO/antibiotics vs. antibiotics-only and SLO-only vs. saline-only, to document the significant differences in gene expressions within these groups. Several genes, MMP9, MMP2, TIMP2, COL1A1, COL12A1, ITGAL, ITGB1, FN1, CCL2, CCL3, CXCL9, TNFα, SMAD7, CD40, IL10, TGFB1, and TLR2, were significantly regulated compared to the unchallenged/untreated control foals. The results of this study demonstrate that enhancement of clinical responses by SLO is consistent with the changes in expression of critical genes in ECM remodeling and inflammatory response pathways.  相似文献