Identification of a candidate gene for the I locus determining the dominant white bulb color in onion (Allium cepa L.).

KEY MESSAGE: Through a map-based cloning approach, a gene coding for an R2R3-MYB transcription factor was identified as a causal gene for the I locus controlling the dominant white bulb color in onion. White bulb colors in onion (Allium cepa L.) are determined by either the C or I loci. The causal gene for the C locus was previously isolated, but the gene responsible for the I locus has not been identified yet. To identify candidate genes for the I locus, an approximately 7-Mb genomic DNA region harboring the I locus was obtained from onion and bunching onion (A. fistulosum) whole genome sequences using two tightly linked molecular markers. Within this interval, the AcMYB1 gene, known as a positive regulator of anthocyanin production, was identified. No polymorphic sequences were found between white and red AcMYB1 alleles in the 4,860-bp full-length genomic DNA sequences. However, a 4,838-bp LTR-retrotransposon was identified in the white allele, in the 79-bp upstream coding region from the stop codon. The insertion of this LTR-retrotransposon created a premature stop codon, resulting in the replacement of 26 amino acids with seven different residues. A molecular marker was developed based on the insertion of this LTR-retrotransposon to genotype the I locus. A perfect linkage between bulb color phenotypes and marker genotypes was observed among 5,303 individuals of segregating populations. The transcription of AcMYB1 appeared to be normal in both red and white onions, but the transcription of CHS-A, which encodes chalcone synthase and is involved in the first step of the anthocyanin biosynthesis pathway, was inactivated in the white onions. Taken together, an aberrant AcMYB1 protein produced from the mutant allele might be responsible for the dominant white bulb color in onions.

Synthesis and Characterisation of Porous Titania-Silica Composite Aerogel for NO(x) and Acetaldehyde Removal.

In this study, the synthesis of porous titania-silica (TiO2-SiO2) composite aerogel at ambient pressure by using non-hazardous chemicals as a source of silica was investigated. TiO2-SiO2 composite aerogels were characterised and their photocatalytic performances were investigated for the removal efficiency of acetaldehyde and NO(x) under UV light. Results showed that porous composite aerogel with aggregated morphology, high surface area and an increased mesoporosity were formed. TiO2-SiO2(1.8) composite, with high Ti/Si ratio, showed the best results in terms of photocatalytic removal of acetaldehyde and nitrogen oxide.

Fabrication of Mesoporous Carbon Tube and Foam: Application as Supports in Enantio-Selective Separation of Optically Pure Amino Acid from Racemates.

The mesoporous monolithic carbon (MMC) foams and carbon tubes were newly fabricated in cm-scale using the mixture of triblock copolymers and phenol/HCHO resin precursors. The regular mesoporosity were formed in the body of MMC foam and carbon fibers. In this work, the organic phases containing chiral ARCA adsorbent and a phase transfer catalyst were coated on the surfaces of mesoporous carbon support, and this ARCA/carbon mixture was adopted for the enantioselective separation of amino acid in the circulation system. (S)-ARCA coated MMC support showed high selcetivity up to 90% for the separation of D-type phenylalanine, serine and tryptophan from racemic mixtures.

Thermoset elastomers derived from carvomenthide.

Renewable thermoset elastomers were prepared using the plant-based monomer carvomenthide. Controlled ring-opening transesterification polymerization of carvomenthide using diethylene glycol as an initiator gave α,ω-dihydroxyl poly(carvomenthide) (HO-PCM-OH), which was subsequently converted to carboxy-telechelic poly(carvomenthide) (HOOC-PCM-COOH) by esterification with excess succinic anhydride through a one-pot, two-step process, leading to no crystallinity, high viscosity, strong thermal resistance, and low glass transition temperature of the resulting functionalized polyester. Thermal curing processes of the resulting 3, 6, and 12 kg mol(-1) prepolymers were achieved with trifunctional aziridine to give cross-linked PCM elastomers. The thermal properties, mechanical behavior, and biocompatibility of the rubbery thermoset products were investigated by differential scanning calorimetry, thermal gravimetric analysis, dynamic mechanical analysis, tensile tests under static and cyclic loads, and cell adherence. These new materials are useful candidates to satisfy the design objective for the engineering of a variety of soft tissues.

Preparation of iron-doped titania from flocculated sludge with iron-titanium composite coagulant.

The main drawback of flocculation process with dye wastewater is the large amount of unrecyclable sludge which needs disposal. A novel process using Ti-salt flocculation to purify wastewater was developed to produced sludge that can be calcined to produce titania. In this study, iron-doped TiO2 nanomaterial was successfully produced from sludge obtained by the flocculation of dye wastewater with a composite floculant including TiCl4 and FeSO4. The titania was characterised using scanning electron microscopy (SEM/EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), and the photodecomposition of acetaldehyde. The XDR results showed that the anatase and rutile structures were found after sludge calcination at 550 degrees C and 640 degrees C respectively. The elemental analyses were carried out using EDX. The rutile titania sample consisted of Ti (35.7 wt.%), Fe (14.7 wt.%), O (42.3 wt.%), P (2.6 wt.%) and Ca (4.7 wt.%). The photocatalytic activity was monitored for the photodecomposition of gas acetaldehyde. Iron-doped titania seems to play an important role in increasing the photocatalytic activity under UV light irradiation.

Synthesis of carbon nanotubes using SBA-15 as a template by the reaction of methane and carbon dioxide.

Multiwalled carbon nanotubes (CNTs) were synthesized using Ni loaded mesoporous SBA-15 as a template by reaction of methane and carbon dioxide. The influences of nickel content on the selectivity and crystallinity of CNTs were investigated. It can be seen that the crooked CNTs with a diameter varied from 9.9, 12.5 to 36.5 nm with creasing content of Ni from 5, 15, and 30 wt%/SBA-15. A uniform diameter and good quality CNTs were obtained in our system.

Synthesis of mesoporous metal oxides and their efficient property for super capacitor application.

A highly ordered CO3O4 and NiO porous crystals were synthesized using cage-containing SBA-16 silica as a template. The porous crystals were characterized by X-ray powder diffraction (XRD), transition electron microscopy (TEM), N2 adsorption/desorption isotherm and cyclic voltammograms (CV). The porous crystal has a high specific area (138.4 m2/g) and it has show much better electrical properties (CV) than bulk.

Preparation of TiO2 nanoparticle from Ti-salt flocculated sludge with dye wastewater.

Dye wastewater flocculation using TiCl4 and FeSO4 coagulants was studied for organic removal and precipitation efficiency. Moreover, TiCl4 was assessed in a pilot-scale flocculation process to investigate organic removal and solution pH effect. A large amount of TiO2 was produced from sludge of Ti-salt flocculation in dye wastewater. This flocculation process simultaneously reduces a large amount of sludge produced from wastewater. The TiO2 nanoparticle was characterized in terms of physical and chemical properties. Results showed that 77.6% of organic matter was removed from dye wastewater when using FeSO4 as coagulant, while TiCl4 degraded 75.9% of organic matter. On the other hand, floc precipitation efficiency was better for TiCl4 if compared with FeSO4. The optimum concentration of TiCl4 for pilot-scale flocculation was found to be equal to 2.1 g/L. DWT (Dye wastewater titania) size was 15-20 nm, mainly doped with carbon atoms and exhibited a dominant anatase structure. DWT was similar to P-25 in decomposing acetaldehyde under UV-irradiation and complete photocatalytic degradation was achieved after 140 min.

Highly active new chiral Co(III) salen catalysts immobilized by electrostatic interaction with sulfonic acid linkages on ordered mesoporous SBA-16 silica.

New chiral cobalt(III) salen complexes immobilized via HO3S-linkers on ordered SBA-16 by electrostatic interactions showed very high activity in enantioselective ring-opening reactions of racemic epoxides.

Application of the bimodal meso/macroporous composite synthesized from MCM-41 sol.

A route to synthesize porous materials with a bimodal macro/mesoscopic pore system has been investigated in this work. Polystyrene with sub-micrometer size was used as a template in the synthesis. The resulting mesoporous silica wall replicated inversely the morphology of polystyrene template and had highly ordered three-dimensional arrays of macro pores. Large and moldable meso/macro porous silica monoliths could be obtained in centimeter scale by using monodispersed polystyrene beads and MCM-41 sol solutions. These bimodal structured porous silicates have been used as supports for asymmetric kinetic resolution of racemic epoxides to synthesize optically pure epoxide.

Synthesis of mesoporous tin oxide and its application as a LNG sensor.

The nanostructured SnO2 gas sensor with Au electrodes and Pt heater has been fabricated as one unit via screen printing process. The gas sensor was tested for CH4 sensing behavior at 350 degrees C in the concentration range of 500-10,000 ppm. Those mesoporous SnO2 sensors exhibited the similar sensoring properties in CH4 and CO detection. The fast speed of response and high sensitivity were obtained for mesoporous tin oxide sensor as compared to non-porous one.