In the nearly six decades since researchers began to explore methods of creating them, exoskeletons have progressed from the stuff of science fiction to nearly commercialized products. While there are still many challenges associated with exoskeleton development that have yet to be perfected, the advances in the field have been enormous. In this paper, we review the history and discuss the state-of-the-art of lower limb exoskeletons and active orthoses. We provide a design overview of hardware, actuation, sensory, and control systems for most of the devices that have been described in the literature, and end with a discussion of the major advances that have been made and hurdles yet to be overcome.

Lower Extremity Exoskeletons and Active Orthoses: Challenges and State-of-the-Art

Tea polyphenols for health promotion

Organotin compounds are ubiquitous contaminants in the environment. The high biological activity of some compounds toward aquatic organisms lead to deleterious impacts in aquatic ecosystems. Here, the aquatic ecotoxicology of organotins is reviewed based on a multidisciplinary approach involving environmental chemical, toxicological, and ecological aspects. Basic results were obtained both with field and laboratory studies, and some of the most important recent results and conclusions are critically reviewed. The contamination of and fate in aquatic systems is reported and linked with effects at different levels of biological organization. Major emphasis is placed on the development of a concept of ecotoxicology that encompasses not only effect assessment alone, but also integrates environmental chemistry with aquatic toxicology. Thereby, the influence of speciation for bioavailability, basic modes of toxic action, and aquatic toxicity are discussed. This case study on organotins allows to a certain extent generalizations to ecotoxicology in general.

Ecotoxicology of organotin compounds.

The impetus for developing analytical methods for phenolic compounds in natural products has proved to be multifaceted. Hundreds of publications on the analysis of this category of compounds have appeared over the past two decades. Traditional and more advanced techniques have come to prominence for sample preparation, separation, detection, and identification. This review provides an updated and extensive overview of methods and their applications in natural product matrices and samples of biological origin. In addition, it critically appraises recent developments and trends, and provides selected representative bibliographic examples.

Extraction, separation, and detection methods for phenolic acids and flavonoids

Organotin compounds in the environment — an overview

4-(N,N-Dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) was synthesised for use as a more reactive, thiol-specific fluorogenic reagent than 4-(aminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (ABD-F). The former had negligible fluorescence whereas its thiol derivatives fluoresced intensely at about 510 nm (excitation occurred at about 380 nm). The DBD-F reacted quantitatively with thiols after 10 min at 50 °C and pH 8.0 and the reaction rates were several times higher than those with ABD-F; it is suggested that the electron withdrawing effect of the dimethylsulphonamide group (SO2NMe2) is larger than that of the sulphonamide group (SO2NH2). No reaction occurred with alanine, proline, cystine or cysteic acid under the same conditions. The fluorescence intensities of the derivatives were found to be higher in neutral and acidic media than in alkaline solutions. The thiol derivatives of DBD-F were separated by high-performance liquid chromatography and detected fluorimetrically, the detection limits being 0.92, 0.16, 0.13, 0.16 and 0.32 pmol for cysteine, glutathione, homocysteine, N-acetylcysteine and α-mercaptopropionylglycine, respectively. The method was applied to the determination of thiols in rat tissues.

Fluorogenic reagent for thiols: 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole.

Molecular species of organotin compounds derived from tri-n-butyltin compounds (Bu 3 Sn + ) were investigated at the parts per billion level in marine products. After being divided into flesh, eggs, and liver, the samples were homogenized and extracted. After purification, the extracts were alkylated with methylmagnesium bromide, and the resulting tetrasubstituted tin compounds were identified by gas-liquid chromatography with a flame photometric detector and gas-liquid chromatographyjmass spectrometry/selective ion monitoring (GC/MS/SIM) and quantified by GC/MS/SIM, using authentic specimens

Molecular species of tri-n-butyltin compounds in marine products

Simultaneous determination of thiols and disulfides by high-performance liquid chromatography with fluorescence detection

Seven flavonoid profiles, some of which were reported to show antiallergic activity in vitro, were surveyed in 28 kinds of tea. Flavonoids were extracted with hot water, hydrolyzed to aglycons, and determined by HPLC. The hydrolysis time needed to obtain the maximum for each aglycon was examined. Flavonols quercetin and kaempferol were found in 17 kinds of tea infusions, as well as Japanese green tea infusions. Myricetin was found in jasmine and pu-erh tea infusions. A flavon, luteolin, was found in 5 kinds of tea infusions including great plantain tea. Apigenin was found in 4 kinds of tea infusions including perilla leaf tea, and scutellarein was found in 3 kinds of tea infusions. Scutellarein, which is a potent antiallergic and low cytotoxic flavonoid, is found in great plantain tea and was detected in perilla leaf and safflower tea infusions at concentrations of approximately 2 mg/g and 0.3 mg/g in dried whole tea leaves, respectively. The presence of scutellarein in both samples was confirmed by LC/MS...

Profiles of Potentially Antiallergic Flavonoids in 27 Kinds of Health Tea and Green Tea Infusions

The externally powered orthosis is one of the necessary devices for rehabilitation of paraplegia patients and hemiplegia patients and spinal-cord-injury victims. However, the main problems of speed, noise, and weight and so on make the morale of the training lower. Then, we thought that there were problems in the actuator. To overcome these problems, we have developed the orthosis externally powered by bi-articular muscle mechanism with a bilateral-servo actuator. Our study suggests such a system as the physically disabled can train with the externally powered orthosis and ambulation device in smooth action.

Yukio Saito

Papers

Fluorogenic reagent for thiols: 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole.

Molecular species of tri-n-butyltin compounds in marine products

Simultaneous determination of thiols and disulfides by high-performance liquid chromatography with fluorescence detection

Profiles of Potentially Antiallergic Flavonoids in 27 Kinds of Health Tea and Green Tea Infusions

Development of externally powered lower limb orthosis with bilateral-servo actuator