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101.
The stereochemistry of palmitoyl-ACP Delta(4) desaturase-mediated dehydrogenation has been examined by tracking the fate of deuterium atoms located on stereospecifically monodeuterated substrates-(4S)- and (4R)-[4-(2)H(1)]-palmitoyl-ACP and (5S)- and (5R)-[5-(2)H(1)]-palmitoyl-ACP. It was found that the introduction of the (Z)-double bond between C-4 and C-5 of a palmitoyl substrate occurs with pro-R enantioselectivity-a result which matches that obtained for a closely related homolog-castor stearoyl-ACP Delta(9) desaturase. These data show that despite the difference in regioselectivity between the two enzymes, the stereochemistry of hydrogen removal is conserved. 相似文献
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OBJECTIVES: The population of the Saguenay-Lac-St-Jean (SLSJ) region (Quebec, Canada) is known to have a relatively high prevalence of certain hereditary disorders, which can be explained by the consequences of founder effects. This study aims at providing new insights on the origins and subregional stratification of these founder effects. METHODS: The genealogies of 300 individuals were reconstructed and analyzed using the BALSAC population register. RESULTS: Inbreeding and kinship levels are higher in Lower Saguenay than in Upper Saguenay and Lac-St-Jean. The population of Lower Saguenay also distinguishes itself because of a fewer number of distinct ancestors. CONCLUSION: Beyond the genetic features that characterize the whole region, SLSJ also displays intraregional variability. Thus it is important to take into account the settlement patterns and the demographic history of this population for a better appraisal of its contemporary genetic structure. 相似文献
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Some new configurations of helical CO2-TEA lasers (TEA-H) generate a converging lens effect. Experimental investigations on the temporal evolution of the lensing effect in these lasers are reported. 相似文献
106.
A 200 joule TEA-CO2 laser has been mode-locked by injection of a nanosecond pulse into a regenerative amplifier operating in an above threshold regime. 25 gigawatt pulses have been obtained. 相似文献
107.
Tay LL Tremblay RG Hulse J Zurakowski B Thompson M Bani-Yaghoub M 《The Analyst》2011,136(8):1620-1626
Brain injury can lead to irreversible tissue loss and functional deficit along with significant health care costs. Raman spectroscopy can be used as a non-invasive technique to provide detailed information on the molecular composition of diseased and damaged tissues. This technique was used to examine acute mouse brain injury, focusing on the motor cortex, a region directly involved in controlling execution of movement. The spectral profile obtained from the injured brain tissue revealed a markedly different signature, particularly in the amide I and amide III vibrational region when compared to that of healthy brain tissue. Most noticeably, there was a significant reduction of the amide I vibration at the acute injury site and the appearance of two distinct features at 1586 and 1618 cm(-1). Complementary immunohistochemical analysis of the injured brain tissue showed an abundant expression of Caspase 3 (a cysteine protease marker used for apoptosis), suggesting that the injury-induced specific Raman shifts may be correlated with cell death. Taken together, this study demonstrates that Raman spectroscopy can play an important role in detecting the changes that occur in the injured brain and provide a possible technology for monitoring the recovery process. 相似文献
108.
Trifluoromethanesulfonimide is an effective catalyst for Friedel-Crafts cyclizations of simple, nonpolarized alkenes with a variety of pendant arenes. A catalyst loading of 0.5 - 1.0 mol % effects clean cyclization to form 5- to 7-membered carbocycles with generally short reaction times and good to excellent yields under reflux or microwave heating. 相似文献
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