AN INEXPENSIVE METHOD FOR CHROMOSOME PREPARATIONS FROM FEATHER PULP IN BIRDS, USING SHORT-TERM TREATMENT WITH COLCHICINE IN-VITRO, DEMONSTRATED ON AMAZONA-AMAZONICA (PSITTACIDAE)

In order to develop an efficient and low-cost technique for obtaining bird chromosome preparations, and to adapt the cytogenetic process of bird sexing for general use at zoos and breeding farms with the technical support of cytogenetics laboratories, we tested variants of the technique described by Giannoni et al. (Genet. Sel. Evol. 23: 123-125, 1991), based on the utilization of cellular material from growing feather pulp cultured in complete medium for six hours. Hanks' saline solution gave satisfactory performance as a substitute for complete medium, with no need to use PHA, serum of collagenase, when utilized in material obtained from feather pulp of Amazona amazonica (Psittacidae).

Water sorption enthalpy-entropy compensation based on isotherms of plum skin and pulp

The net isosteric heat and entropy of water sorption were calculated for plum, based on sorption isotherms obtained by the static gravimetric method at different temperatures (20 to 70 degrees C). The Guggenheim-Anderson-deBoer model was applied to the experimental data giving a good agreement between experimental and calculated values. The net isosteric heat of water sorption, estimated by applying Claussius-Clapeyron equation to sorption isotherms, was found to be different for plum skin and pulp, mainly at low moisture contents, and could be well adjusted by an empirical exponential relationship. Plots of enthalpy in contrast to entropy provided the isokinetic temperatures for skin and pulp, indicating an enthalpy-controlled sorption process. Thermodynamic data on water sorption for plums are not found in literature, as opposed to prunes for which the data are abundant.

Cytotoxic effects of cleansing solutions recommended for chemical lavage of pulp exposures

Purpose: To evaluate the in vitro cytotoxic effects of three cleansing solutions used for chemical lavage of pulp exposures. Materials and Methods: the immortalized odontoblast cell line (MDPC-23) was plated (30,000 cells/cm(2)) and incubated for 72 hrs in 24-well dishes. After counting the cell number under inverted light microscopy, 20 mul of the experimental and control solutions were added to 980 mul of fresh culture medium. Then, hydrogen peroxide (3%, H2O2), sodium hypochlorite (6%, NaOCl) or calcium hydroxide-saline solution (5g of Ca(OH)(2) in 10 mi of sterile distilled water) were added to wells for experimental Groups 1, 2 and 3, respectively. The positive and negative control groups received Syntac Sprint bonding agent (SS) and phosphate buffered saline (PBS), respectively. Following incubation for 120 min the cell number was counted again, the cell morphology was evaluated by scanning electron microscopy (SEM) and the cell metabolism was determined by the methyltetrazolium (MTT) assay. The scores obtained from cell counting and MTT assay were analyzed with an ANOVA followed by Fisher's PLSD tests. Results: H2O2 NaOCl solutions, and SS bonding agent were more cytotoxic than Ca(OH)2 or PBS. In the groups with H2O2 Or SS, only a few cells remained attached to the bottom of wells. The difference between these two groups was not statistically significant. H2O2, NaOCl and SS depressed the mitochondrial enzyme response by 97.7%, 97.3%, and 95.0%, respectively. on the other hand, Ca(OH)2 depressed the metabolic activity of cells by only 5%. While H2O2, NaOCl and SS caused extreme changes on the cell morphology, neither Ca(OH)2 nor PBS promoted dramatic changes in the cell morphology.

Effect of apparent viscosity on fluidized bed drying process parameters of guava pulp

Pressure drop and minimum fluidization velocity were experimentally studied in a vibro-fluidized bed of inert particles subjected to different vibration intensities during drying of guava pulp. Maltodextrin was added to the pulp in order to prevent stickiness between particles and the consequent bed collapse. Pulps were initially concentrated, resulting in pastes with different soluble solids content, and a constant fraction of maltodextrin was guaranteed in the final pulp samples. The pulp rheological behavior as affected by temperature and total soluble solids content, including maltodextrin, was evaluated and the effect of pulp apparent viscosity on pressure drop and minimum vibro-fluidization velocity were investigated. Two types of inert particles -3.6 mm glass beads and 3 mm Teflon cylinders were tested and, due to lower pressure drop presented by Teflon cylinders during operation of the dry vibro-fluidized bed, these particles were adopted for pulp drying process. Increasing pulp apparent viscosity caused a considerable increase in the vibro-fluidized bed pressure drop during pulp drying and, as a consequence resulted in a larger value of minimum vibro-fluidization velocity. on the other hand, the negative effect of increasing apparent viscosity could be attenuated by increasing the fluidized bed vibration intensity, which could prevent stickiness between particles. (c) 2006 Elsevier Ltd. All rights reserved.

Effect of maltodextrin and arabic gum in water vapor sorption thermodynamic properties of vacuum dried pineapple pulp powder

Moisture equilibrium data of pineapple pulp (PP) powders with and without additives - 18% maltodextrin (MD) or 18% gum Arabic (GA) - were determined at 20, 30, 40 and 50 degrees C by using the static gravimetric method in a water activity range of 0.06-0.90. The obtained isotherms were sigmoid, typical type 111, and the Guggenhein-Anderson-de Boer (GAB) model was fitted to the experimental data of equilibrium moisture content versus water activity. Addition of additives was shown to affect the isotherms in such a way that, at the same water activity, samples PP + GA and PP + MD presented lower equilibrium moisture content and were not so affected by varying temperature. The net isosteric heats of sorption of pulp powders with additives were higher (less negative) than those of pineapple pulp powders, suggesting that there are more active polar sites in the product without addition of GA or MD. An empirical exponential relationship could describe the heat of sorption dependence on the material moisture content. (C) 2007 Elsevier Ltd. All rights reserved.