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Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) of oligosaccharides and polysaccharides has been investigated in detail.It is demonstrated that cationized species of oligosaccharides, [MNa] and [MK] , are dominant products under the MALDI condition, and negative ions of oligosaccharides are not formed to any significant extent in this process. The molecular masses of polysaccharides are similarly determined by positive-and negative-ion MALDI-MS with the help of column chromatography. The distinction between positive-and negative-ion MALDI mass spectra of oligo-and polysaccharides indicates that the MALDI processes for saccharides vary with molecular mass. The matrix plays a more important role in the ionization process for oligosaccharides, while in the desorption process for polysaccharides. # 1998 John Wiley & Sons, Ltd. Received 1 October 1997; Revised 28 January 1998; Accepted 1 February 1998 Rapid Commun. Mass Spectrom. 12, 345-348 (1998 In recent years, with the new recognition of the physiological functions of saccharides, scientists have begun to give more attention to the study of these biomolecules. 1Following the extensive studies of proteins and nucleic acids, saccharides have become another exciting topic in the area of life science. Their properties are closely related to their molecular masses, and molecular mass distributions of polysaccharides are significant in this regard. Matrixassisted laser desorption/ionization mass spectrometry (MALDI-MS), a superior technique for molecular mass determination, 2-4 has been extensively used in the field of biochemistry since 1987.5 Though in its early stage, MALDI-MS study of saccharides has shown great potential. As shown in recent research, 6-13 MALDI-MS is a powerful tool for not only molecular mass determination but also the structure analysis of saccharides. The post-source decay technique has opened up new perspectives in the structural analysis of carbohydrates.11-13 However, the mechanisms of the MALDI process for saccharides have not been investigated as much as those for peptides and proteins, and the negative-ion MALDI mass spectra of saccharides that could provide important information have not been paid much attention. In this paper, positive-and negative-ion MALDI mass spectra of oligosaccharides and polysaccharides have been studied, and the functions of the matrix in the MALDI process of saccharides have been discussed. EXPERIMENTAL MaterialsRaffinose and stachyose were purchased from Sigma Chemical Co., USA; dextran T40 (MW 40 000), dextran T70 (MW 70 000), Sephadex DEAE A50, Sephadex G100 and Sepharose CL-4B were the products of Pharmacia, Sweden. Matrices used were: 100 mM 2,5-dihydroxybenzoic acid (2,5-DHB), 100 mM sinapinic acid (SA) and 30 mM a-cyano-4-hydroxyl cinnamic acid (CHCA), all obtained from Linear Scientific Company, USA.Solutions of raffinose, stachyose, dextran T40 and dextran T70 were prepared in distilled water. Dextran T40 and dextran T70 were purified by sepharose CL-4B column chromatogra...

Computer vision has achieved impressive progress in recent years. Meanwhile, mobile phones have become the primary computing platforms for millions of people. In addition to mobile phones, many autonomous systems rely on visual data for making decisions and some of these systems have limited energy (such as unmanned aerial vehicles also called drones and mobile robots). These systems rely on batteries and energy efficiency is critical. This article serves two main purposes: (1) Examine the state-of-the-art for low-power solutions to detect objects in images. Since 2015, the IEEE Annual International Low-Power Image Recognition Challenge (LPIRC) has been held to identify the most energy-efficient computer vision solutions. This article summarizes 2018 winners' solutions. (2) Suggest directions for research as well as opportunities for low-power computer vision.

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