887 research outputs found
Patterns of Coastal Land Cover and Estuarine Habitat Quality: Application of Long-term Monitoring Data
2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio
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OA06-02. Monospecific Expansion of SIVmac251 During Acute Infection Masks Multiple Transmitted Virus Variants Revealed During the Chronic Phase
Combined ultrasonographic and neurographic examination: A new technique to evaluate phrenic nerve function
Recent invasion of the mountain birch Betula pubescens ssp. tortuosa above the treeline due to climate change: genetic and ecological study in northern Sweden
Aminomethylation/hydrogenolysis as an alternative to direct methylation of metalated isoquinolines - a novel total synthesis of the alkaloid 7-hydroxy-6-methoxy-1-methylisoquinoline
Highly-substituted isoquinolines are important scaffolds in syntheses of natural products and in drug development and hence, effective synthetic approaches are required. Here we present a novel method for the introduction of a methyl group at C1 of isoquinolines. This is exemplified by a new total synthesis of the alkaloid 7-hydroxy-6-methoxy-1-methylisoquinoline. Direct metalation of 7-benzyloxy-6-methoxyisoquinoline with Knochel-Hauser base, followed by cuprate-mediated methylation gives the target alkaloid directly, but separation from the educt is cumbersome. Quenching the metalated intermediate with Eschenmoser's reagent gives an easy to clean tertiary benzylamine, which, after quaternization with iodomethane, is easily converted into the desired 1-methylisoquinoline by hydrogenolysis of both the benzylamine and benzyl ether groups
Follow-up study of sensory-motor polyneuropathy in Type 1 (insulin-dependent) diabetic subjects after simultaneous pancreas and kidney transplantation and after graft rejection
The influence of successful simultaneous pancreas and kidney transplantation on peripheral polyneuropathy was investigated in 53 patients for a mean observation period of 40.3 months. Seventeen patients were followed-up for more than 3 years. Symptoms and signs were assessed every 6 months using a standard questionnaire, neurological examination and measurement of sensory and motor nerve conduction velocities. While symptoms of polyneuropathy improved (pain, paraesthesia, cramps, restless-legs) and nerve conduction velocity increased, there was no change of clinical signs (sensation, muscle-force, tendon-reflexes). Following kidney-graft-rejection there was a slight decrease of nerve conduction verlocity during the first year, which was not statistically significant. Following pancreas-graft rejection there was no change of nerve conduction velocity during the first year. Comparing the maximum nerve conduction velocity of the patients with pancreas-graft-rejection to the nerve conduction velocities of these patients at the end of the study, there was a statistically significant decrease of 6.5 m/s.
In conclusion, we believe that strict normalization of glucose metabolism alters the progressive course of diabetic polyneuropathy. It may be stabilized or partly reversed after successful grafting even in long-term diabetic patients
Electromagnetic energy penetration in the self-induced transparency regime of relativistic laser-plasma interactions
Two scenarios for the penetration of relativistically intense laser radiation
into an overdense plasma, accessible by self-induced transparency, are
presented. For supercritical densities less than 1.5 times the critical one,
penetration of laser energy occurs by soliton-like structures moving into the
plasma. At higher background densities laser light penetrates over a finite
length only, that increases with the incident intensity. In this regime
plasma-field structures represent alternating electron layers separated by
about half a wavelength by depleted regions.Comment: 9 pages, 4 figures, submitted for publication to PR
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