Yoichiro Ito

Bio: Yoichiro Ito is an academic researcher from National Institutes of Health. The author has contributed to research in topics: Countercurrent chromatography & High-performance liquid chromatography. The author has an hindex of 50, co-authored 546 publications receiving 13915 citations. Previous affiliations of Yoichiro Ito include Osaka City University.

Droplet countercurrent chromatography

Abstract: A DROPLET CONTERCURRENT CHROMATOGRAPHIC ALL-LIQUID SEPARATION TECHNIQUE FOR PARTITIONING A SOLUTE BETWEEN A STEADY STREAM OF DROPLETS OF MOVING THE PHASE AND A COLUMN OF SURROUNDING STATIONARY LIQUID PHASE. MILLIGRAM QUANTITIES OF BIOCHEMICALS MAY BE SEPARATED USING THIS PROCESS. D R A W I N G

High-speed countercurrent chromatography

Abstract: I. INTRODUCTION During the past 20 years countercurrent chromatography (CCC) has been steadily improved in both partition efficiency and separation times.1-15 The original helix CCC and the successively developed nonhelix preparative-scale CCC schemes, such as droplet CCC16,17 and locular CCC,17 required relatively long separating times; sizeable separation usually exceeded 24 hr. During the last decade, development of various flow-through centrifuge schemes, such as the flow-through coil planet centrifuge18,19 (CPC), angle rotor CPC,20 elution centrifuge,21 horizontal flow-through CPC,22-26 toroidal CPC,27,28 and nonsynchronous flow-through CPC,29-31 has substantially shortened the separation times so that efficient separations became possible with overnight runs.

Countercurrent chromatography: liquid-liquid partition chromatography without solid support.

Abstract: The liquid-liquid partition chromatographic system reported here involves a long helix of narrow-bore tubing. When the coiled tube is filled with one phase of a two-phase system and fed with the other phase, phase-interchange takes place in each turn of the coil, leaving a segment of the former phase as the stationary phase. Consequently, solutes present in either phase are subjected to a multistep partition process. The column efficiency, estimated on a separation of dinitrophenyl amino acids, is comparable to that of gas chromatography.

Plant Products as Antimicrobial Agents

Abstract: The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and “leads” which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.

Plant phenolics: extraction, analysis and their antioxidant and anticancer properties.

Abstract: Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed.

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

Abstract: 介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Micro total analysis systems. 2. Analytical standard operations and applications.

Abstract: After having reviewed some aspects of microfluidic system preparation in the first part (1), in this second part of the review we will cover a number of standard operations (namely: sample preparation, sample injection, sample manipulation, reaction, separation, and detection) as well as some biological applications of micro total analysis systems (namely: cell culture, polymerase chain reaction, DNA separation, DNA sequencing, and clinical diagnostics). As previously, we will include papers issued from different scientific journals as well as useful abstracts from three conference proceedings: MEMS, Transducers, and μTAS. In this second part, we do not include the period covered by the history section (1975-1997) from part 1 but try to cover the relevant examples of the literature published between January 1998 and March 2002. We briefly describe articles that struck us as needing special attention, while more “standard” papers are dutifully reported in groups of interest. An article might be included in more than one section, depending on the ideas developed in it.

Genesis and development of DPPH method of antioxidant assay

Abstract: α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method offers the first approach for evaluating the antioxidant potential of a compound, an extract or other biological sources. This is the simplest method, wherein the prospective compound or extract is mixed with DPPH solution and absorbance is recorded after a defined period. However, with the advancement and sophistication in instrumental techniques, the method has undergone various modifications to suit the requirements, even though the basic approach remains same in all of them. This article presents a critical review on various developments to the DPPH method.