Covalent attachment of functional protein to polymer surfaces: a novel one-step dry process.

The attachment of bioactive protein to surfaces underpins the development of biosensors and diagnostic microarrays. We present a surface treatment using plasma immersion ion implantation (PIII) to create stable covalent binding sites for the attachment of functional soya-bean peroxidase (SBP). Fourier transform infrared spectra of the surfaces show that protein is retained on the surface after boiling in sodium dodecyl sulphate and sodium hydroxide, which is indicative of covalent attachment. The activity of SBP on the treated surfaces remains high in comparison with SBP attached to control surfaces over the course of 11 days. Surface plasmon resonance was used to show that the surface coverage of the attached protein is close to a monolayer. We describe the potential of the PIII treatment method to be used as a one-step dry process to create surfaces for large-scale protein micro- or nanopatterning.     

Application of chemical composition and infusion colour difference analysis to quality estimation of jasmine-scented tea

Infusion chemical composition, colour difference indicators and volatile constituents of seventeen jasmine‐scented tea samples and their correlation with sensory total quality score given by tea‐tasting panel were studied by techniques of HPLC, colour difference metre and gas chromatograph. Spearman's linear correlation analysis showed that concentration of nitrogen, caffeine, catechin, epicatechin, catechin gallate, total catechins, terpineol, nerol and infusion light‐black indicator ΔL, yellow‐blue indicator Δb, total colour difference indicator ΔE were significantly correlated with sensory total quality score, respectively. Regression of the total quality score upon twelve components extracted from thirty‐six tested indicators by principal component analysis could properly estimate total quality score of two jasmine‐scented tea samples which were not included in the seventeen samples used to construct the regression model.     

Studies of the esterification of dextran: routes to bioactive polymers and graft copolymers

Problems associated with the esterification of dextran as a means of coupling bioactive molecules or introduction of functionality suitable for graft polymerization are considered. In particular, the importance of eliminating side-reactions which incorporate into dextran unwanted residues, e.g. groups containing nitrogen, is emphasized and practical techniques for minimizing this are described. We have developed a formamide-based solvent suitable for esterification with the aid of dicyclohexyl carbodiimide (DCC) and carbonyl di-imidazole (CDI) as coupling agents. The preferred catalyst is p-pyrrolidinopyridine. CDI has the advantage of enabling dimethylsulphoxide to be used as solvent for dextran and other hydroxylic polymers without inducing oxidation of hydroxyl groups. This coupling agent is flexible and offers a choice of two routes to esterification, each having its merits. We have optimized conditions for coupling by use of butyric acid as model. Esterification of dextran has been employed in the preparation of soluble bioactive macromolecules by coupling the anti-platelet agent (I) and also in the synthesis of graft copolymers via introduction of 2-bromopropionate groups. Crosslinking of dextran and the polymerization of dipyridamole have been effected by use of CDI.     

Bioactive polymers LVII. A novel drug delivery system based on 5-nitro-2-furaldehyde-semicarbazone and poly(acrylic acid-co-vinyl alcohol)

The coupling of 5-nitro-2-furaldehyde-semicarbazone on to poly(acrylic acid-co-vinyl alcohol) copolymer by the use of dicyclohexylcarbodiimide as activator has been studied. On the basis of an experimental design, the influence of different parameters is studied (activator/support, drug/support, reaction time, solvent volume) in order to determine the optimum conditions for obtaining the maximum amount of the coupled drug on the support.     

Spectral quality of photo-selective shade nettings improves antioxidants and overall quality in selected fresh produce after postharvest storage

Growing vegetables under shade nets is currently becoming popular in summer to provide protection from high intensities of light. High temperatures and light quality affect postharvest quality and storage life of vegetables. Photo-selective shade netting technology is an emerging agro-technological concept that aims at the improvement of crop quality by the modification of spectral light and provides physical protection of the crop. Incorporation of various light-dispersive and reflective chromatic additives in the photo-selective nets is responsible for the modification of spectral quality, especially in the UV 200–400 nm, visible (400–700 nm), or far-red (FR; also known as “near infrared”; 705–740 nm) in the infrared region of the spectral region. Altered light-quality changes under the photo-selective nets were shown to improve the accumulation of phytochemicals and aroma compounds, and ultimately, the growth, yield, and quality of the selected vegetables such as tomatoes, sweet peppers, lettuce, and aromatic herbs. The postharvest quality of fresh produce is also influenced by environmental conditions such as light, average temperature, minimum temperature, and day-night temperature differences. During production, light quality under the photo-selective shade nets had a positive effect on the quality parameters and phytochemical content in fresh produce after postharvest storage.

The review includes the use of photo-selective netting in protected agriculture as a preharvest tool to improve aroma volatiles, antioxidants, and overall quality of fresh produce after postharvest storage.     

CONTROL OF THE DIMETHYL SULPHIDE CONTENT OF BEER BY REGULATION OF THE COPPER BOIL

In pilot brewing trials where wort boil time was varied from 15 min up to 2 hours the DMS contents of the resultant beers were greatly altered without substantial effect on many other aspects of beer quality. The worts were separately fermented by two yeast strains and a consistent difference between DMS levels of the pairs of beers was found which was almost independent of the boil time. The breakdown of the malt-derived DMS precursor in boiling wort was found to be a first order reaction having a rate constant of about 0.02 min^?1, implying a half life of about 35 min. The breakdown rate of S-methylmethionine in a boiling sucrose solution at pH 5.3 was similar. Free DMS was found to leave this wort substitute rapidly, again as a first order process, but with a rate constant of 0.18 min^?1 (t_1/2 ～ 4 min) when the evaporation rate was 17%/h.     

Bioactive core–shell structure of TiC/TiO2/SrCO3 coating on carbon black particles for bone tissue formation: Fabrication,characterization, and biological functions

Although carbon-based nanomaterials, such as carbon nanotubes, graphene, and carbon dots, have attracted much attention for bone tissue regeneration and engineering due to the advantages of being lightweight, mechanical stability, and remarkable ability for bone repair, their toxicity and dispersity are the most concern and greatly limiting their clinical uses. In this article, the surface modification of carbon black particles based on core–shell structure design as a promising candidate material for bone tissue engineering applications is presented. TiC/TiO₂/SrCO₃-coated carbon black particles were prepared via molten salt synthesis and hydrothermal process at various temperatures to study the effects of temperature on crystal structure, morphologies, surface wettability, and biological functions. Phase composition, morphologies, and elemental distributions were studied by X-ray diffraction, field-emission scanning electron microscope, and energy-dispersive X-ray spectroscopy, respectively. Cell proliferation, cell viability, alkaline phosphatase (ALP) activity, and calcium deposition were also investigated. The investigation showed that the reaction temperature played an important role in the crystallinity, phase formation, nanotopography, and biological functions of the particles. The particles treated at 250°C offered favored surface properties of roughness, composition, crystallite size, and wettability for cell adhesion, proliferation, ALP activity, and calcium deposition. As a result, these bioactive core–shell particles would be a promising filler material for bone tissue engineering applications.     

湖北长阳绿茶挥发油成分的GC／MS分析

用气相色谱／质谱联用法分析了湖北长阳绿茶挥发油的化学成分，分离出93个组分，鉴定了84个化合物，挥发油中含芳樟醇、香叶醇、香茅醇等多种香气成分。     

工业甲醇精馏重分含量的测定

本方法采用色谱法分析甲醇精馏中热重组分的含量，为甲醇精馏生产提供快速，准确的分析方法。