A Lower Irradiation Dose of 308 nm Monochromatic Excimer Light Might Be Sufficient for Vitiligo Treatment: A Novel Insight Gained from In Vitro and In Vivo Analyses

A 308 nm monochromatic excimer light (MEL) is widely used to treat patients with vitiligo. However, dose optimization still needs to be clarified. This study aimed to obtain objective evidence regarding various doses of MEL irradiation, induced cell level changes in vitro, and skin level alterations in vivo. Cultured human keratinocytes were irradiated with MEL using various doses. After irradiation at low doses, stem cell factor, endothelin-1, and glycoprotein nonmetastatic melanoma protein B, factors that activate and protect melanocytes, were found to be significantly elevated in keratinocytes. After irradiation using medium and high doses, inflammatory cytokines were induced. The amount of ATP released and the level of inflammasome activation, which are known to be related to interleukin-1β activation, were also increased. The back skin of guinea pigs and mice were irradiated with MEL at varying doses. After irradiation, an increase of epidermal melanin and epidermal melanocytes was confirmed, using the minimal erythemal dose or less. In rhododendrol-induced leukoderma guinea pigs, a much lower dose of MEL irradiation was effective, when compared with the effective dose for control guinea pigs. Our results suggest that a lower irradiation dose of MEL might be sufficient and more suitable for repigmentation in vitiligo treatment.     

Simple picrate paper kit for determination of the cyanogenic potential of cassava flour

A simple picrate paper kit method was developed for the semiquantitative determination of the cyanogenic potential for cassava flour. The method involved the addition of linamarase and pH 8 phosphate buffer (absorbed in a filter paper disc) to 100 mg of flour +0·5 ml water placed in a small vial. A rectangle of yellow picrate paper attached to a plastic strip was added and the vial capped and left overnight. The yellow paper changed colour towards brown and its colour was compared with that of a standard colour card with 10 shades of colour which corresponded with cyanogenic potentials of 0–800 mg HCN equivalents kg⁻¹ flour (ppm). To obtain a more accurate measure of cyanogenic potential (±20%) the paper was eluted with water and the absorbance measured at 510 nm. The cyanogenic potential in ppm was determined from a calibration graph. The methodology is available in kit form. The simple method may be used in the field by a relatively unskilled person. The more accurate method requires a spectrophotometer and is suitable for use in simple laboratories in developing countries. © 1998 SCI.     

A simple and rapid method for isolating cassava leaf linamarase suitable for cassava cyanide determination

A simple method was developed for isolating cassava leaf linamarase. It involved homogenising the leaves in a buffer containing polyvinylpolypyrrolidone, followed by ammonium sulphate precipitation, filtration and partial purification of the enzyme by hydrophobic interaction chromatography. All stages of the enzyme preparation were carried out at room temperature and it was completed within 90 min. A linamarin-indicator strip for checking the activity of the enzyme preparation was also developed. This isolation technique which has been developed into a simple kit should be suitable for laboratories in developing countries where the enzyme is needed to determine the cyanogenic potential of cassava and its products. © 1997 SCI.     

Dietary fibre content of thirteen apple cultivars

Fibre composition of the following 13 apple cultivars was studied: ‘Cortland’, ‘Empire’, ‘Fuji’, ‘Golden Delicious’, ‘Gala’, ‘Granny Smith’, ‘Jonagold’, ‘Mutsu’, ‘McIntosh’, ‘Delicious’, ‘Rome’, ‘Stayman’ and ‘York’. Fruit samples from each of these cultivars were analysed for non-starch cell wall materials (NSCWM) and non-starch polysaccharides (NSP). NSCWM was further fractionated into soluble and insoluble fibre fractions. Both NSCWM and NSP content were found to be significantly influenced by cultivar. NSCWM content ranged from 19·1 g kg⁻¹ apple flesh in ‘Fuji’ to 36·2 g kg⁻¹ in ‘York’. Mean(±SD) NSCWM content of all the cultivars was 23·1±4·5 g kg⁻¹. NSP content of apple flesh ranged from 13·8 g kg⁻¹ in ‘McIntosh’ to 28·7 g kg⁻¹ in ‘York’ with the overall mean for all cultivars being 17·9±4·2 g kg⁻¹. Relative amount of monosaccharides found in the hydrolysates of apple fibre also varied among cultivars. The greatest difference was observed in galactose content. ©1997 SCI     

A minimalist approach to polarization resistance measurements in a reinforced concrete structure

In the curriculum of future civil engineers, electrochemical concepts are often neglected, even though this knowledge is essential to adequately maintain reinforced concrete structures in a chloride-exposed environment. Experiments are necessary to consolidate key theoretical concepts, but laboratory experience often involves complex and expensive electronic equipment that may obscure the basic procedures at work. This paper presents a simple minimalistic electrochemical test for polarization resistance measurements by which students can learn basic concepts of corrosion electrochemistry and estimate the corrosion rate as a key parameter for estimation of the remaining service life of concrete structures. The focus is on avoiding unnecessary complications and providing an experiment that can be readily implemented for a wider student reach.     

Regressive Approximation von Viskositätsfunktionen am Beispiel niederdruck-plasmabehandelter LDPE-Pulver

Regressive approximation of viscosity functions of low-pressure-plasma-treated disperse LDPE-materials The low-pressure-plasma effects of the processing gases argon, oxygen, and nitrogen, respectively, on plasma-exposed disperse LDPE-materials have been investigated. For the evaluation of experimental data, rheological characterisation concerning plasma-induced changes both in specific viscous and elastic characteristics of the treated materials is discussed by means of various rheological properties. The determination of the so-called “zero viscosity” making use of suitable developed mathematical modelling is of main interest.     

西九文化区

正OMA发展西九文化区,必须面对一项挑战:将一个盛载政府极大抱负,以及持分者多元利益的超大型多用途项目,转化成一个既有趣又严肃、既有规划又允许即兴、既中国化又国际化的文化区。这个文化区规模庞大,但不失亲密融洽的感觉;富地标性,但十分谦和;容易理解,却能带来惊喜。为避免造成过分冲击,OMA采纳了一种每个香港市民都熟悉的建筑类型作为方案的发展     

Phase assembly and electrical conductivity of spark plasma sintered CeO2–ZrO2 ceramics

Ce _x Zr_1?x O₂ (x = 0.10, 0.16 and 0.33) nanocrystalline powders were obtained by a two-step synthesis technique and sintered by spark plasma sintering (SPS). As consequence of the reduction of Ce⁴⁺ to Ce³⁺ species by carbon in the graphite environment in SPS, phase assemblies including tetragonal, monoclinic and pyrochlore phases were generated in the ceramics during the sintering process. The electrical conductivity was highly dependent on phase assembly and atmosphere (N₂, H₂ and O₂). A significant decrease in the activation energy was noticed in the ceramics with high pyrochlore content when measuring the conductivity in H₂ atmosphere, consequence of the strong reduction promoted in these ceramics during the measurement. Equal conduction behavior with similar activation energy was observed in all the ceramics when measuring in O₂ atmosphere.     

Intracellularly Degradable Hydrogen‐Bonded Polymer Capsules

The assembly of low‐fouling polymer capsules with redox‐responsive behavior and intracellular degradability is reported. Thiol‐containing poly(2‐ethyl‐2‐oxazoline) (PEtOxMA_SH) brushes are synthesized by atom transfer radical polymerization (ATRP) of oligo(2‐ethyl‐2‐oxazoline)methacrylate and glycidyl methacrylate (GMA) and subsequent ring‐opening reaction of the GMA. Sequential deposition of PEtOxMA_SH/poly(methacrylic acid) (PMA) multilayers onto silica (SiO₂) particle templates and crosslinking through disulfide formation yield stable capsules after the removal of the SiO₂ templates by buffered hydrofluoric acid (HF). The redox‐responsive nature of the disulfide crosslinking groups enables the degradation of these capsules under simulated intracellular conditions at pH 5.9 and 5 mm glutathione (GSH). Furthermore, capsule degradation is observed after incubation with dendritic (JAWS II) cells. Even at high capsule‐to‐cell ratios, PEtOxMA_SH capsules show only negligible cytotoxicity. Quartz crystal microgravimetry (QCM) studies, using 100% human serum, reveal that films prepared from PEtOxMA_SH exhibit low‐fouling properties. The degradation and low‐fouling properties are promising for application of PEtOxMA_SH films/capsules for the delivery and triggered release of therapeutics.