A complex of oxidised chitosan and silver ions grafted to cotton fibres with bacteriostatic properties.

The laccase/TEMPO system was employed to oxidise the C6 primary hydroxyl group on the chitosan (CS) to form a carboxyl group to obtain oxidised chitosan (C-COS). The silver-oxidised chitosan complex(C-COS-Ag) was prepared by reacting C-COS with silver nitrate, then C-COS-Ag and cotton fibres were subjected to a reaction to prepare bacteriostatic fibres. FT-IR and XPS analysis showed that: Ag and C-COS were combined in these forms: Ag, [Ag(NH)] OH, -COOAg, and AgO.

Color evolution of poplar wood chips and its response to lignin and extractives changes in autohydrolysis pretreatment.

Combining chemi-mechanical pulping with autohydrolysis pretreatment is an efficient and value-added utilization approach for lignocellulosic biomass in paper industry. To further promote the utilization of autohydrolyzed biomass in chemi-mechanical pulping, the color evolution of poplar wood chips in autohydrolysis pretreatment and its chromogenic mechanism were investigated by using CIELab color system, FT-IR, NMR and GPC. The results showed that the total color difference ΔE* increased obviously, which were remarkable as the combined hydrolysis factor (CHF) increased.

Construction of Marker-Free Genetically Modified Maize Using a Heat-Inducible Auto-Excision Vector.

Gene modification is a promising tool for plant breeding, and gradual application from the laboratory to the field. Selectable marker genes (SMG) are required in the transformation process to simplify the identification of transgenic plants; however, it is more desirable to obtain transgenic plants without selection markers. Transgene integration mediated by site-specific recombination (SSR) systems into the dedicated genomic sites has been demonstrated in a few different plant species.

Cationic cellulose nanofibers as sustainable flocculant and retention aid for reconstituted tobacco sheet with high performance.

The study that cationic cellulose nanofibers (CCNF) acts as sustainable flocculant and retention aid of precipitated calcium carbonate (PCC) for the preparation of reconstituted tobacco sheet (RTS) was carried out, thanks to the properties of CCNF. In this work, the enhanced flocculation, reflocculation and size properties of PCC flocs induced by CCNF were investigated via a focused beam reflectance measurement (FBRM) system. The physical properties of RTS such as bulk and air permeability etc.

Infection of Embryonic Callus with Enables High-Speed Transformation of Maize.

Several approaches have recently been adopted to improve -mediated transformation of maize; however, about eight months of in vitro culture are still required to isolate transgenic plants. Furthermore, genetic transformation of maize depends on immature embryos, which greatly increases costs. Here, we report a method that ensures the competency of an embryogenic callus secondary culture under laboratory conditions for -mediated transformation.

The study of inhibitory effects and mechanism of carboxylate chitooligomer on melanin, prepared by laccase/TEMPO system.

A carboxylate chitooligomer (C-COS) containing carboxyl groups attached to chitooligomer (COS) molecules has been prepared by laccase/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) system, which is a green-chemistry method. Several experiments were designed to evaluate inhibition effects on melanin and mechanisms of C-COS. The results indicated that C-COS exhibited more distinct anti-melanogenic effects compared to COS.

Nickel(ii)-catalyzed tandem C(sp)-H bond activation and annulation of arenes with -dibromoalkenes.

A nickel(ii)/silver(i)-catalyzed tandem C(sp)-H activation and intramolecular annulation of arenes with dibromoalkenes has been successfully achieved, which offers an efficient approach to the 3-methyleneisoindolin-1-one scaffold. Attractive features of this system include its low cost, ease of operation, and its ability to access a wide range of isoindolinones.

The hydration mechanism and hydrogen bonding structure of 6-carboxylate chitooligosaccharides superabsorbent material prepared by laccase/TEMPO oxidation system.

6-carboxylate chitooligosaccharides (6-CCOS), as a superabsorbent material, were prepared by way of the laccase/TEMPO oxidation system. It exhibited a higher moisture-absorption ability and stronger affinity for water. To understand the real reasons for this, the hydrogen bonding structure of 6-CCOS and the hydration mechanism of the molecule were investigated using infrared (IR), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR).

Molecular structural differences between maize leaf and endosperm starches.

The morphology, whole molecular size distribution and chain-length distribution of maize leaf starch have been characterized and compared to its endosperm starch, to better understand differences between leaf and endosperm starch structure, and the relationship with the functions of starch in these organs. Leaf starch is found to have amylopectin with much shorter chains (virtually none with a degree of polymerization, DP, above 70) than the endosperm amylopectin, which has significant numbers of chains with DP up to ∼120, and has much smaller molecular size (and is present at a much lower amount) than endosperm starch. It is postulated that these pronounced differences arise from the distinct starch synthesis pathways in these organs, and are consistent with the starches' distinct botanical functions: short-term storage requiring relatively rapid degradation for leaf starch, and high crystallinity and high energy density requiring slow degradation for endosperm starch.

Oxidation of primary hydroxyl groups in chitooligomer by a laccase-TEMPO system and physico-chemical characterisation of oxidation products.

The aim of this study was to investigate the oxidation of chitooligomer by a laccase-TEMPO system which had not previously been examined. Chitooligomer was treated with laccase and TEMPO in order to evaluate the potential of a laccase-TEMPO system to improve the moisture absorption, moisture retention, and antioxidant abilities of chitooligomer. Chitooligomer was prepared by degradation of high molecular weight chitosan with hydrogen peroxide followed by oxidation using a laccase-TEMPO system.

Photo-assisted proton exchange and chemical etching on Fe-doped lithium niobate crystals.

We report the photo-assisted proton exchange and chemical etching on Fe-doped LiNbO(3) crystals. Selective proton exchange and chemical etching are realized through the 455nm-laser irradiation on the crystal surface in pyrophosphoric acid. Optical microscopy and Micro-IR spectroscopy analysis show that the hydrogen incorporation is confined spatially by the laser irradiation.

The 5' stem-loop and its role in mRNA stability in maize S cytoplasmic male sterility.

The co-transcribed orf355-orf77 region of the mitochondrial genome is associated with S cytoplasmic male sterility (CMS-S) in maize; the amounts of its 1.6- and 2.8-kb transcripts were previously shown to be greatly reduced in fertility-restored microspores relative to the amounts in sterile plants.

[Progress of molecular biology of CMS in maize].

In the paper,we have summarized the molecular biological accomplishment acquired and accepted by most of maize researchers on CMS of maize. A brief review of current molecular biological progress of CMS of maize are displayed in the paper. These progresses concern in the positioning,cloning and maker-assisted selection of nucleic genes associated with fertility,expression and cloning of cytoplasmic genes associated with male sterility.

Expression analysis of orf77 and R region in mitochondrial DNA of S-type CMS maize.

It is generally recognized that S type of CMS in maize associated with the recombination region R in mitochondria. Complicated DNA recombination and changes of transcripts of R are observed in several subgroups of S cytoplasm. R region includes two open reading frames (orf355 and orf77) and they are all chemeric.

[Construction of physical map and polymorphism analysis of mtDNA region R from Mo17CMS-J of maize].

Total DNA from twenty-six CMS lines of maize under Mo17, 77 and W23 nuclear background were used for PCR amplification, including N, T, C, S four groups of cytoplasms. The primers was prefabricated according the sequence of R region published by Zebala (1997). Through these amplifications, mitochondrial DNA fragments were obtained from maize total DNA.