A thermostable DNA polymerase was used in an in vitro DNA amplification procedure, the polymerase... more A thermostable DNA polymerase was used in an in vitro DNA amplification procedure, the polymerase chain reaction. The enzyme, isolated from Thermus aquaticus, greatly simplifies the procedure and, by enabling the amplification reaction to be performed at higher temperatures, significantly improves the specificity, yield, sensitivity, and length of products that can be amplified. Single-copy genomic sequences were amplified by a factor of more than 10 million with very high specificity, and DNA segments up to 2000 base pairs were readily amplified. In addition, the method was used to amplify and detect a target DNA molecule present only once in a sample of 10(5) cells.
A procedure for extracting plasmid DNA from bacterial cells is described. The method is simple en... more A procedure for extracting plasmid DNA from bacterial cells is described. The method is simple enough to permit the analysis by gel electrophoresis of 100 or more clones per day yet yields plasmid DNA which is pure enough to be digestible by restriction enzymes. The principle of the method is selective alkaline denaturation of high molecular weight chromosomal DNA while covalently closed circular DNA remains double-stranded. Adequate pH control is accomplished without using a pH meter. Upon neutralization, chromosomal DNA renatures to form an insoluble clot, leaving plasmid DNA in the supernatant. Large and small plasmid DNAs have been extracted by this method.
8 typically slower than ϳ1 km s −1 ) might differ significantly from what is assumed by current m... more 8 typically slower than ϳ1 km s −1 ) might differ significantly from what is assumed by current modelling efforts 27 . The expected equation-of-state differences among small bodies (ice versus rock, for instance) presents another dimension of study; having recently adapted our code for massively parallel architectures (K. M. Olson and E.A, manuscript in preparation), we are now ready to perform a more comprehensive analysis.
We describe a technique for image encoding in which local operators of many scales but identical ... more We describe a technique for image encoding in which local operators of many scales but identical shape serve as the basis functions. The representation differs from established techniques in that the code elements are localized in spatial frequency as well as in space.
Classification and regression trees are prediction models constructed by recursively partitioning... more Classification and regression trees are prediction models constructed by recursively partitioning a data set and fitting a simple model to each partition. Their name derives from the usual practice of describing the partitioning process by a decision tree. This article reviews some widely available algorithms and compares their capabilities, strengths and weaknesses in two examples.
Epoxy embedding methods of Glauert and Kushida have been modified so as to yield rapid, reproduci... more Epoxy embedding methods of Glauert and Kushida have been modified so as to yield rapid, reproducible, and convenient embedding methods for electron microscopy. The sections are robust and tissue damage is less than with methacrylate embedding.
A thermostable DNA polymerase was used in an in vitro DNA amplification procedure, the polymerase... more A thermostable DNA polymerase was used in an in vitro DNA amplification procedure, the polymerase chain reaction. The enzyme, isolated from Thermus aquaticus, greatly simplifies the procedure and, by enabling the amplification reaction to be performed at higher temperatures, significantly improves the specificity, yield, sensitivity, and length of products that can be amplified. Single-copy genomic sequences were amplified by a factor of more than 10 million with very high specificity, and DNA segments up to 2000 base pairs were readily amplified. In addition, the method was used to amplify and detect a target DNA molecule present only once in a sample of 10(5) cells.
A procedure for extracting plasmid DNA from bacterial cells is described. The method is simple en... more A procedure for extracting plasmid DNA from bacterial cells is described. The method is simple enough to permit the analysis by gel electrophoresis of 100 or more clones per day yet yields plasmid DNA which is pure enough to be digestible by restriction enzymes. The principle of the method is selective alkaline denaturation of high molecular weight chromosomal DNA while covalently closed circular DNA remains double-stranded. Adequate pH control is accomplished without using a pH meter. Upon neutralization, chromosomal DNA renatures to form an insoluble clot, leaving plasmid DNA in the supernatant. Large and small plasmid DNAs have been extracted by this method.
8 typically slower than ϳ1 km s −1 ) might differ significantly from what is assumed by current m... more 8 typically slower than ϳ1 km s −1 ) might differ significantly from what is assumed by current modelling efforts 27 . The expected equation-of-state differences among small bodies (ice versus rock, for instance) presents another dimension of study; having recently adapted our code for massively parallel architectures (K. M. Olson and E.A, manuscript in preparation), we are now ready to perform a more comprehensive analysis.
We describe a technique for image encoding in which local operators of many scales but identical ... more We describe a technique for image encoding in which local operators of many scales but identical shape serve as the basis functions. The representation differs from established techniques in that the code elements are localized in spatial frequency as well as in space.
Classification and regression trees are prediction models constructed by recursively partitioning... more Classification and regression trees are prediction models constructed by recursively partitioning a data set and fitting a simple model to each partition. Their name derives from the usual practice of describing the partitioning process by a decision tree. This article reviews some widely available algorithms and compares their capabilities, strengths and weaknesses in two examples.
Epoxy embedding methods of Glauert and Kushida have been modified so as to yield rapid, reproduci... more Epoxy embedding methods of Glauert and Kushida have been modified so as to yield rapid, reproducible, and convenient embedding methods for electron microscopy. The sections are robust and tissue damage is less than with methacrylate embedding.
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