Birch and eucalyptus kraft pulps were treated with sulfite solutions in neutral conditions (pH 7) at 170 °C for 60 min and at 190 °C for 180 min. The pulps were analyzed for kappa number, viscosity, carbohydrate composition, and optical properties. Additionally, UV resonance Raman (UVRR) spectroscopy was applied to collect information on the contents of hexenuronic acid (HexA), lignin, and its ...

The effect of alkaline pulping parameters (temperature, effective alkali (EA) and sulphidity) on the hexenuronic acid (HexA) content of Portuguese Eucalyptus globulus pulps was studied. The HexA content was calculated on a pentosan basis. Unlike softwood pulping, the amount of this acid increased during kraft cooking and only started to decrease in the final stage of delignification (kappa numb...

A study was carried out on totally chlorine-free (TCF) bleachability of dimethyl formamide (DMF) treated bagasse pulps exposed to CZ-3 and FP 90031-sp strains of white-rot fungus Ceriporiopsis subvermispora. This process involved an oxygen and peroxide stage bleaching sequence. The effect of enzymatic stage on bleachability properties was studied and compared with control pulps, processed witho...

IMMUNOHISTOCHEMICAL STUDY OF PHENOTYPES OF DENDRITIC CELLS IN DENTAL PULPS FROM NON-CARIOUS AND CARIOUS TEETH By Melissa A. Harmon, DDS A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University. Virginia Commonwealth University, 2007 Major Director: Karan J. Replogle, DDS, MS Chair, Department of Endodontic...

Nanoscale porosity is critical for cellulose reactivity and can be detrimentally affected by wet pressing. The present study evaluated how wet pressing reduced the nanoscale porosity of a set of pulps produced from sugarcane bagasse. The pulps were produced using hydrothermal treatments, followed by either 160 °C alkaline (sodium hydroxide) or 190 °C organosolv (ethanol-water) pulping. Pulping ...

abstract this study was carried out in japan for evaluation of the relationship between phenolic compounds and skin color indices of 3 apples cultivars including ‘fuji’, ‘jonathan’ and ‘jonagold’, in 2006. in ‘jonathan’, l* (lightness) increased with decreasing red color of skin. in ‘jonagold’, chroma increased with increasing red color. but in ‘fuji’, there was no detectable difference between...

Free and conjugated sterols are among the main compounds responsible for pitch deposition in the manufacture of wood chemical pulps, making difficult the implementation of totally chlorine free bleaching (TCF) and closure of bleach plant circuits. In this work, the suitability of oxidative enzymes in efficiently removing sterols from eucalypt pulps is revealed. The enzymatic treatment was appli...

Three selected alkali-based organosolv pulps (alkali-sulfite-anthraquinone-methanol (ASAM), alkali-anthraquinone-methanol (organocell) and ethanol-soda) from agrofibre crop giant reed (Arundo donax L.) were bleached by an ozone-based TCF (totally chlorine- free) bleaching sequence AZE(R)QP (where A is an acidic pulp pre-treatment, Z is an ozone stage, (E(R)) is an alkaline extraction in the pre...

The aim of this work is to prove the suitability of a new alkaline and halotolerant bacterial laccase (SilA) produced by Streptomyces ipomoea CECT 3341 to enhance the conventional chemical bleaching process of an industrial eucalyptus kraft pulp. The laccase used for this study was a recombinant laccase obtained from cultures of E. coli BL21 (DE3) grown in LB liquid medium. The biobleaching exp...

The polyphenolic contents and the antioxidant activity of the skins and pulps of different grape cultivars were estimated using HPLC and DPPH antioxidant assay, respectively. The phenolics and flavonoids identified were quercetin, kaempferol, caffeic acid, p-coumaric acid, cinnamic acid, and (-)-epicatechin. The total phenolic contents were found to be the highest in the grape skin of Flouxa (>...