Preparation of TiO2 Film through Hydrolysis of Titanium Butoxide and Interaction between Sensitizing Dyes and the Film

A method of preparation of stable, homogeneous and controlled thickness TiO2 film through hydrolysis of Ti(OC4H(9))(4) is introduced in detail. The structure and property of the film have been investigated by means of SEM and FT-IR techniques. The strong quenching effect between sensitizing dyes and TiO2 film is observed in their fluorescence spectra.

Lanthanide metal complexes for the hydrolysis of ribonucleoside 3',5'-cyclic phosphate and deoxyribonucleoside 3',5'-cyclic phosphate

Ytterbium(III) and praseodymium(III) complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) can hydrolyze the phosphodiester linkage of 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic deoxyadenosine monophosphate (dcAMP). Both cAMP and dcAMP are hydrolyzed with high selectivity, yielding predominantly 3'-monophosphates. The selectivity and activity for hydrolyzing cAMP and dcAMP by lanthanide metal(III) complexes and lanthanide metal ions are compared.

Hydrolysis of adenosine monophosphate and guanosine monophosphate by lanthanides

The hydrolysis of adenosine-5'-monophosphate(5'-AMP) and guanosine-5'-monophosphate(5'-GMP) by lanthanides was investigated. 5'-AMP and 5'-GMP was efficiently hydrolyzed by cerium(III) chloride under air at pH 9 and 37 degrees C, and other lanthanides (III) showed less efficiency at the same condition. The hydrolysis rate of 5'-AMP by cerium was greater than that of 5'-GMP. UV spectra showed that Ce(III) was oxidized to Ce(IV) in the reaction mixture. The active species for the hydrolysis of 5'-AMP and 5'-GMP was ascribed to the Ce(IV) hydroxide cluster in the reaction mixture.

INVESTIGATIONS OF HYDROLYSIS KINETICS OF ATROPINE SULFATE BY ELECTROANALYSIS AT THE WATER NITROBENZENE INTERFACE

The hydrolysis kinetics of atropine sulphate has been investigated by cyclic voltammetry at the water/nitrobenzene interface. The transfer process is diffusion controlled and the transfer species is a 1:1 proton-atropine complex. Two main factors, pH and temperature, which have notable effects on the hydrolysis rate, are illustrated. The most suitable pH for atropine to be preserved in aqueous solution and related parameters were estimated.

Salt-assisted acid hydrolysis of chitosan to oligomers under microwave irradiation

The effect of inorganic salts such as sodium chloride on the hydrolysis of chitosan in a microwave field was investigated. While it is known that microwave heating is a convenient way to obtain a wide range of products of different molecular weights only by changing the reaction time and/or the radiation power, the addition of some inorganic salts was shown to effectively accelerate the degradation of chitosan under microwave irradiation. The molecular weight of the degraded chitosan obtained by microwave irradiation was considerably lower than that obtained by traditional heating. Moreover, the molecular weight of degraded chitosan obtained by microwave irradiation assisted under the conditions of added salt was considerably lower than that obtained by microwave irradiation without added salt. Furthermore, the effect of ionic strength of the added salts was not linked with the change of molecular weight. FTIR spectral analyses demonstrated that a significantly shorter time was required to obtain a satisfactory molecular weight by the microwave irradiation-assisted inorganic salt method than by microwave irradiation without inorganic salts and conventional technology. (C) 2005 Elsevier Ltd. All rights reserved.

Salt-assisted acid hydrolysis of starch to D-glucose under microwave irradiation

The effect of inorganic salts on the hydrolysis of starch in a microwave field was investigated and it was found that some inorganic salts can effectively accelerate the acid hydrolysis of starch. The yield of D-glucose reached 111 wt% (equal to the theoretical yield). (C) 2001 Published by Elsevier Science Ltd. All rights reserved.

Rubisco small subunit, chlorophyll a/b-binding protein and sucrose : fructan-6-fructosyl transferase gene expression and sugar status in single barley leaf cells in situ. Cell type specificity and induction by light

Chungui Lu, Olga A. Koroleva, John F. Farrar, Joe Gallagher, Chris J. Pollock, and A. Deri Tomos (2002). Rubisco small subunit, chlorophyll a/b-binding protein and sucrose : fructan-6-fructosyl transferase gene expression and sugar status in single barley leaf cells in situ. Cell type specificity and induction by light. Plant Physiology, 130 (3) pp.1335-1348 Sponsorship: BBSRC RAE2008

Kinetic Analysis of Ester Hydrolysis

A two-week multi-step experiment that introduces students to mechanistic organic chemistry and substituent effects. A simple preparation of differentially substituted para-nitrophenyl benzoates is followed by ester hydrolysis with monitoring by UV-Vis spectroscopy to provide rate data for the reaction.

Fundamental studies of sourdoughs fermented with Weissella cibaria and Lactobacillus plantarum: influence on baking characteristics, sensory profiles and in vitro starch digestibility of gluten-free breads

The application of sourdough can improve texture, structure, nutritional value, staling rate and shelf life of wheat and gluten-free breads. These quality improvements are associated with the formation of organic acids, exopolysaccharides (EPS), aroma or antifungal compounds. Initially, the suitability of two lactic acid bacteria strains to serve as sourdough starters for buckwheat, oat, quinoa, sorghum and flours was investigated. Wheat flour was chosen as a reference. The obligate heterofermentative lactic acid bacterium (LAB) Weissella cibaria MG1 (Wc) formed the EPS dextran (a α-1,6-glucan) from sucrose in situ with a molecular size of 106 to 107 kDa. EPS formation in all breads was analysed using size exclusion chromatography and highest amounts were formed in buckwheat (4 g/ kg) and quinoa sourdough (3 g/ kg). The facultative heterofermentative Lactobacillus plantarum FST1.7 (Lp) was identified as strong acidifier and was chosen due to its ubiquitous presence in gluten-free as well as wheat sourdoughs (Vogelmann et al. 2009). Both Wc and Lp, showed highest total titratable acids in buckwheat (16.8 ml; 26.0 ml), teff (16.2 ml; 24.5 ml) and quinoa sourdoughs (26.4 ml; 35.3 ml) correlating with higher amounts of fermentable sugars and higher buffering capacities. Sourdough incorporation reduced the crumb hardness after five days of storage in buckwheat (Wc -111%), teff (Wc -39%) and wheat (Wc -206%; Lp -118%) sourdough breads. The rate of staling (N/ day) was reduced in buckwheat (Ctrl 8 N; Wc 3 N; Lp 6 N), teff (Ctrl 13 N; Wc 9 N; Lp 10 N) and wheat (Ctrl 5 N; Wc 1 N; Lp 2 N) sourdough breads. Bread dough softening upon Wc and Lp sourdough incorporation accounted for increased crumb porosity in buckwheat (+10.4%; +4.7), teff (+8.1%; +8.3%) and wheat sourdough breads (+8.7%; +6.4%). Weissella cibaria MG1 sourdough improved the aroma quality of wheat bread but had no impact on aroma of gluten-free breads. Microbial shelf life however, was not prolonged in any of the breads regardless of the starter culture used. Due to the high prevalence of insulin-dependent diabetes mellitus particular amongst coeliac patients, glycaemic control is of great (Berti et al. 2004). The in vitro starch digestibility of gluten-free breads with and without sourdough addition was analysed to predict the GI (pGI). Sourdough can decrease starch hydrolysis in vitro, due to formation of resistant starch and organic acids. Predicted GI of gluten-free control breads were significantly lower than for the reference white wheat bread (GI=100). Starch granule size was investigated with scanning electron microscopy and was significantly smaller in quinoa flour (<2 μm). This resulted in higher enzymatic susceptibility and hence higher pGI for quinoa bread (95). Lowest hydrolysis indexes for sorghum and teff control breads (72 and 74, respectively) correlate with higher gelatinisation peak temperatures (69°C and 71°C, respectively). Levels of resistant starch were not increased by addition of Weissella cibaria MG1 (weak acidifier) or Lactobacillus plantarum FST1.7 (strong acidifier). The pGI was significantly decreased for both wheat sourdough breads (Wc 85; Lp 76). Lactic acid can promote starch interactions with gluten hence decreasing starch susceptibility (Östman et al. 2002). For most gluten-free breads, the pGI was increased upon sourdough addition. Only sorghum and teff Lp sourdough breads (69 and 68, respectively) had significantly decreased pGI. Results suggest that the increase of starch hydrolysis in gluten-free breads was related to mechanism other than presence of organic acids and formation of resistant starch.

Regions of the alpha 1-adrenergic receptor involved in coupling to phosphatidylinositol hydrolysis and enhanced sensitivity of biological function.

Regions of the hamster alpha 1-adrenergic receptor (alpha 1 AR) that are important in GTP-binding protein (G protein)-mediated activation of phospholipase C were determined by studying the biological functions of mutant receptors constructed by recombinant DNA techniques. A chimeric receptor consisting of the beta 2-adrenergic receptor (beta 2AR) into which the putative third cytoplasmic loop of the alpha 1AR had been placed activated phosphatidylinositol metabolism as effectively as the native alpha 1AR, as did a truncated alpha 1AR lacking the last 47 residues in its cytoplasmic tail. Substitutions of beta 2AR amino acid sequence in the intermediate portions of the third cytoplasmic loop of the alpha 1AR or at the N-terminal portion of the cytoplasmic tail caused marked decreases in receptor coupling to phospholipase C. Conservative substitutions of two residues in the C terminus of the third cytoplasmic loop (Ala293----Leu, Lys290----His) increased the potency of agonists for stimulating phosphatidylinositol metabolism by up to 2 orders of magnitude. These data indicate (i) that the regions of the alpha 1AR that determine coupling to phosphatidylinositol metabolism are similar to those previously shown to be involved in coupling of beta 2AR to adenylate cyclase stimulation and (ii) that point mutations of a G-protein-coupled receptor can cause remarkable increases in sensitivity of biological response.

Optimization of a total acid hydrolysis based protocol for the quantification of carbohydrate in macroalgae

Accurate quantification of carbohydrate content of biomass is crucial for many bio-refining applications. The standardised NREL two stage complete acid hydrolysis protocol was evaluated for its suitability towards seaweeds, as the protocol was originally developed for lignocellulosic feedstocks. The compositional differences between the major polysaccharides in seaweeds and terrestrial plants, and seaweed’s less recalcitrant nature, could suggest the NREL based protocol may be too extreme. Underestimations of carbohydrate content through the degradation of liberated sugars into furan compounds may yield erroneous data. An optimised analysis method for carbohydrate quantification in the brown seaweed L. digitata was thus developed and evaluated. Results from this study revealed stage 1 of the assay was crucial for optimisation however stage 2 proved to be less crucial. The newly optimised protocol for L. digitata yielded 210 mg of carbohydrate per g of biomass compared to a yield of only 166 mg/g from the original NREL protocol. Use of the new protocol on two other species of seaweed also gave consistent results; higher carbohydrate and significantly lower sugar degradation products generation than the original protocol. This study demonstrated the importance of specific individual optimisations of the protocol for accurate sugar quantification, particularly for different species of seaweed