Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Context (language use). The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

Desorption–ionization mass spectrometry on porous silicon

Abstract: Desorption mass spectrometry has undergone significant improvements since the original experiments were performed more than 90 years ago1. The most dramatic change occurred in the early1980s with the introduction of an organic matrix2,3,4 to transfer energy to the analyte. This reduces ion fragmentation but also introduces background ions from the matrix. Here we describe a matrix-free strategy forbiomolecular mass spectrometry based on pulsed-laser desorption–ionization from a porous silicon5 surface. Our method uses porous silicon to trap analytes deposited on the surface, and laser irradiation to vaporize and ionize them. We show that the method works at femtomole and attomole levels of analyte, and induces little or no fragmentation, in contrast to what is typically observed with other such approaches6,7,8,9,10,11. The ability to perform these measurements without a matrix3,4,12,13 also makes itmore amenable to small-molecule analysis. Chemical14 and structural15 modification of the porous silicon has enabled optimization of the ionization characteristics of the surface. Our technique offers good sensitivity as well as compatibility with silicon-based microfluidics and microchip technologies.

Mutant Gene That Changes Protein Composition and Increases Lysine Content of Maize Endosperm

Abstract: Preliminary tests have shown that the endosperms of maize seeds homozygous for the opaque-2 mutant gene have a higher lysine content than normal kernels. As a critical test, a backcross progeny was divided into opaque-2 and normal kernels, the endosperms separated, and the amino acids determined. The opaque-2 endosperms had a different amino acid pattern and 69 percent more lysine than the normal seeds. The major reason for these changes is the synthesis of proteins with a greater content of basic amino acids in the acid-soluble fraction of the mutant endosperm. This is accompanied by a reduction in the ratio of zein to glutelin.

Colonial Discourse and Post-colonial Theory: A Reader

Abstract: Preface Acknowledgements An Introduction: Colonial Discourse and Post-colonial Theory 1. Theorising Colonised Cultures and Anti-Colonial Resistance 2. Theorising the West: Theorising Gender 3. Theorising Post-Coloniality: Intellectuals and Institutions 4. Theorising Post-Coloniality: Discourse and Identity 5. Reading from Theory Bibliography

RCS—a system for version control

Abstract: An important problem in program development and maintenance is version con- trol, i.e., the task of keeping a software system consisting of many versions and configurations well organized. The Revision Control System (RCS) is a software tool that assists with that task. RCS manages revisions of text documents, in particular source programs, documentation, and test data. It automates the storing, retrieval, log- ging and identification of revisions, and it provides selection mechanisms for composing configurations. This paper introduces basic version control concepts and discusses the practice of version control using RCS. For conserving space, RCS stores deltas, i.e., differences between successive revisions. Several delta storage methods are discussed. Usage statistics show that RCS's delta storage method is space and time efficient. The paper concludes with a detailed survey of version control tools.

Shape Discrimination Using Fourier Descriptors

Abstract: Description or discrimination of boundary curves (shapes) is an important problem in picture processing and pattern recognition. Fourier descriptors (FD's) have interesting properties in this respect. First, a critical review is given of two kinds of FD's. Some properties of the FD's are given and a distance measure is proposed, in terms of FD's, that measures the difference between two boundary curves. It is shown how FD's can be used for obtaining skeletons of objects. Finally, experimental results are given in character recognition and machine parts recognition.