Multiphase flow in the vascular system of wood: From microscopic exploration to 3-D Lattice Boltzmann experiments

This paper provides insights into liquid free water dynamics in wood vessels based on Lattice Boltzmann experiments. The anatomy of real wood samples was reconstructed from systematic 3-D analyses of the vessel contours derived from successive microscopic images. This virtual vascular system was then used to supply fluid-solid boundary conditions to a two-phase Lattice Boltzmann scheme and investigate capillary invasion of this hydrophilic porous medium. Behavior of the liquid phase was strongly dependent on anatomical features, especially vessel bifurcations and reconnections. Various parameters were examined in numerical experiments with ideal vessel bifurcations, to clarify our interpretation of these features. (c) 2010 Elsevier Ltd. All rights reserved.

Genetic variation for anatomic traits and volume shrinkage and their correlation with wood basic density in an Eucalyptus camaldulensis Dehn base population

Eucalyptus camaldulensis has great importance in Brazil because of their phenotypic plasticity for different environmental conditions, as soils, altitudes and rainfall. This study is an investigation of a base population of E. camaldulensis from Australia through a progeny test implanted in Selviria, MS. The trial was established in a randomized block design, with 25 families and 60 replications of single tree plots. Genetic parameters for anatomic traits and volume shrinkage were estimated, as well as their correlations with wood basic density. No significant differences among progenies were observed for the traits studied. The additive genetic variation coefficient at individual and among progeny levels ranged from low (0.26%) to high (16.98%). The narrow sense heritability at individual and family means levels also ranged from low (0.01) to high (0.87). This indicates that some traits are under strong genetic control and can be improved by selection. In the present situation, in order to attain the highest genetic gains, the sequential selection among and within progeny would be recommended.

Sterilization of Medical Devices by Ethylene Oxide, Determination of the Dissipation of Residues, and Use of Green Fluorescent Protein as an Indicator of Process Control

Ethylene oxide (EO) is used to sterilize Oxygenator and Tubing applied to heart surgery. Residual levels of EO and its derivatives, ethylene chlorohydrin (ECH) and ethylene glycol (EG), may be hazardous to the patients. Therefore, it must be removed by the aeration process. This study aimed to estimate the minimum aeration time for these devices to attain safe limits for use (avoiding excessive aeration time) and to evaluate the Green Fluorescent Protein (GFP) as a biosensor capable of best indicating the distribution and penetration of EO gas throughout the sterilization chamber. Sterilization cycles of 2, 4, and 8 h were monitored by Bacillus atrophaeus ATCC 9372 as a biological indicator (131) and by the GFP. Residual levels of EO, ECH, and EG were determined by gas chromatography (GC), and the residual dissipation was studied. Safe limits were reached right after the sterilization process for Oxygenator and after 204 h of aeration for Tubing. In the 2 h cycle, the GFP concentration decreased from 4.8 (+/- 3.2)% to 7.5 (+/- 2.5)%. For the 4 h cycle, the GFP concentration decreased from 17.4 (+/- 3.0)% to 21.5 (+/- 6.8)%, and in the 8 h cycle, it decreased from 22.5 (+/- 3.2)% to 23.9 (+/- 3.9)%. This finding showed the potentiality for GFP applications as an EO biosensor. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9113: 626-630, 2009

Key residues characteristic of GATA N-fingers are recognized by FOG

Protein-protein interactions play significant roles in the control of gene expression. These interactions often occur between small, discrete domains within different transcription factors. In particular, zinc fingers, usually regarded as DNA-binding domains, are now also known to be involved in mediating contacts between proteins. We have investigated the interaction between the erythroid transcription factor GATA-1 and its partner, the 9 zinc finger protein, FOG (Friend of GATA). We demonstrate that this interaction represents a genuine finger-finger contact, which is dependent on zinc coordinating residues within each protein. We map the contact domains to the core of the N-terminal zinc finger of GATA-1 and the 6th zinc finger of FOG. Using a scanning substitution strategy we identify key residues within the GATA-1 N-finger which are required for FOG binding. These residues are conserved in the N-fingers of all GATA proteins known to bind FOG, but are not found in the respective C-fingers, This observation may, therefore, account for the particular specificity of FOG for N-fingers, Interestingly, the key N-finger residues are seen to form a contiguous surface, when mapped onto the structure of the N-finger of GATA-1.

H-1-NMR structural studies of a cystine-linked peptide containing residues 71-93 of transthyretin and effects of a Ser84 substitution implicated in familial amyloidotic polyneuropathy

The Ile-->Ser84 substitution in the thyroid hormone transport protein transthyretin is one of over 50 variations found to be associated with familial amyloid polyneuropathy, a hereditary type of lethal amyloidosis. Using a peptide analogue of the loop containing residue 84 in transthyretin, we have examined the putative local structural effects of this substitution using H-1-NMR spectroscopy. The peptide, containing residues 71-93 of transthyretin with its termini linked via a disulfide bond, was found to possess the same helix-turn motif as in the corresponding region of the crystallographically derived structure of transthyretin in 20% trifluoroethanol (TFE) solution. It therefore, represents a useful model with which to examine the effects of amyloidogenic substitutions. In a peptide analogue containing the Ile84-->Ser substitution it was found that the substitution does not greatly disrupt the overall three-dimensional structure, but leads to minor local differences at the turn in which residue 84 is involved. Coupling constant and NOE measurements indicate that the helix-turn motif is still present, but differences in chemical shifts and amide-exchange rates reflect a small distortion. This is in keeping with observations that several other mutant forms of transthyretin display similar subunit interactions and those that have been structurally analysed possess a near native structure. We propose that the Ser84 mutation induces only subtle perturbations to the transthyretin structure which predisposes the protein to amyloid formation.

Controlling leucine zipper specificity with interfacial hydrophobic residues

Dimerisation of leucine zippers results from the parallel association of alpha-helices to form a coiled coil. Coiled coils comprise a heptad repeat, denoted as (abcdefg)(n), where residues at positions a and d are hydrophobic and constitute the core of the dimer interface. Charged amino acids at the e and g positions of the coiled coil are thought to be the major influence on dimerisation specificity through the formation of attractive and repulsive interhelical electrostatic interactions. However, the variability of a-position residues in leucine zipper transcription factors prompted us to investigate their influence on dimerisation specificity. We demonstrate that mutation of a single interfacial a-position Ala residue to either Val, Ile or Leu significantly alters the homo- and heterodimerisation specificities of the leucine zipper domain from the c-Jun transcription factor. These results illustrate the importance of a-position residues in controlling leucine zipper dimerisation specificity in addition to providing substantial contributions to dimer stability.

Identification of residues involved in binding of IL5 to beta(com) using beta(IL3) and beta(com) chimeras

In mice there are two forms of the beta chain used in the IL3 receptor system, beta(com) and beta(IL3). beta(com) is used by the IL3, ILS and GM-CSF receptors whereas Pns is only used in the IL3 receptor. In this work an assay was developed to identify residues of beta(IL3) that restrict IL5 activity. It was found that such residues reside within the 2nd CRM of the molecule. Furthermore, when residues in the beta(IL3) B'-C' loop were replaced with beta(com) sequence a form of beta(IL3) was produced that was able to respond to IL5. This region is also responsible for IL3 binding to beta(IL3) in the absence of alpha chain. It is therefore an important structural motif of beta(com) and beta(IL3) responsible for both ligand interaction and specificity. (C) 1999 Federation of European Biochemical Societies.

Residues of zeta-cypermethrin in bovine tissues and milk following pour-on and spray application

The depletion of zeta-cypermethrin residues in bovine tissues and milk was studied. Beef cattle were treated three times at 3-week intervals with 1 ml 10 kg(-1) body weight of a 25 g litre(-1) or 50 g litre(-1) pour-on formulation (2.5 and 5.0 mg zeta-cypermethrin kg(-1) body weight) or 100 mg kg(-1) spray to simulate a likely worst-case treatment regime. Friesian and Jersey dairy cows were treated once with 2.5 mg zeta-cypermethrin kg(-1) in a pour-on formulation. Muscle, liver and kidney residue concentrations were generally less than the limit of detection (LOD = 0.01 mg kg(-1)). Residues in renal-fat and back-fat samples from animals treated with 2.5 mg kg(-1) all exceeded the limit of quantitation (LOQ = 0.05 mg kg(-1)), peaking at 10 days after treatment. Only two of five kidney fat samples were above the LOQ after 34 days, but none of the back-fat samples exceeded the LOQ at 28 days after treatment. Following spray treatments, fat residues were detectable in some animals but were below the LOQ at all sampling intervals. Zeta-cypermethrin was quantifiable (LOQ = 0.01 mg kg(-1)) in only one whole-milk sample from the Friesian cows (0.015 mg kg(-1), 2 days after treatment). In whole milk from Jersey cows, the mean concentration of zeta-cypermethrin peaked 1 day after treatment, at 0.015 mg kg(-1), and the highest individual sample concentration was 0.025 mg kg(-1) at 3 days after treatment. Residues in milk were not quantifiable beginning 4 days after treatment. The mean concentrations of zeta-cypermethrin in milk fat from Friesian and Jersey cows peaked two days after treatment at 0.197 mg kg(-1) and 0.377 mg kg(-1), respectively, and the highest individual sample concentrations were 2 days after treatment at 0.47 mg kg(-1) and 0.98 mg kg(-1), respectively. (C) 2001 Society of Chemical Industry.

Determination of T1pH relaxation rates in charred and uncharred wood and consequences for NMR quantitation

The performance of three different techniques for determining proton rotating frame relaxation rates (T1pH) in charred and uncharred woods is compared. The variable contact time (VCT) experiment is shown to over-estimate T1pH, particularly for the charred samples, due to the presence of slowly cross-polarizing C-13 nuclei. The variable spin (VSL) or delayed contact experiment is shown to overcome these problems; however, care is needed in the analysis to ensure rapidly relaxing components are not overlooked. T1pH is shown to be non-uniform for both charred and uncharred wood samples; a rapidly relaxing component (T1pH = 0.46-1.07 ms) and a slowly relaxing component (T1pH = 3.58-7.49) is detected in each sample. T1pH for each component generally decreases with heating temperature (degree of charring) and the proportion of rapidly relaxing component increases. Direct T1pH determination (via H-1 detection) shows that all samples contain an even faster relaxing component (0.09-0.24 ms) that is virtually undetectable by the indirect (VCT and VSL) techniques. A new method for correcting for T1pH signal losses in spin counting experiments is developed to deal with the rapidly relaxing component detected in the VSL experiment. Implementation of this correction increased the proportion of potential C-13 CPMAS NMR signal that can be accounted for by up to 50% for the charred samples. An even greater proportion of potential signal can be accounted for if the very rapidly relaxing component detected in the direct T1pH determination is included; however, it must be kept in mind that this experiment also detects H-1 pools which may not be involved in H-1-C-13 cross-polarization. (C) 2002 Elsevier Science (USA).

Production of beta-fructofuranosidases by Aspergillus niveus using agroindustrial residues as carbon sources: Characterization of an intracellular enzyme accumulated in the presence of glucose

The production of beta-fructofuranosidases by Aspergillus niveus, cultivated under submerged fermentation using agroindustrial residues, was investigated. The highest productivity of beta-fructofuranosidases was obtained in Khanna medium supplemented with sugar cane bagasse as carbon source. Glucose enhanced the production of the intracellular enzyme, whereas that of the extracellular one was decreased. The intracellular beta-fructofuranosidase was a trimeric protein of approximately 141 kDa (gel filtration) with 53.5% carbohydrate content, composed of 57 kDa monomers (SDS-PAGE). The optimum temperature and optimum pH were 60 degrees C and 4.5, respectively. The purified enzyme showed good thermal stability and exhibited a half-life of 53 min at 60 degrees C. beta-Fructofuranosidase activity was slightly activated by Cu(2+), Mn(2+), Mg(2+), and Na(+) at 1 mM concentration. The enzyme hydrolyzed sucrose, raffinose, and inulin, with K(d) values of 5.78 mM, 5.74 mM, and 1.74 mM, respectively. (C) 2008 Elsevier Ltd. All rights reserved.

Residues of spinosad in the tissues of sheep after aerosol treatment of blowfly myiasis

Objective To measure the residues of spinosad and chlorhexidine in the tissues of sheep after treatment of blowfly strike. Procedure Fourteen sheep with natural myiasis and 12 with artificial infestations of Lucilia cuprina larvae had the wool removed over their infestations and were treated with an aerosol wound dressing containing spinosad and chlorhexidine. Sheep were killed up to 14 days after treatment and residues of the chemicals measured in tissues. Results Chlorhexidine was not detected in any tissue. Residues of spinosad were highest in fat, lowest in muscle and intermediate in liver and kidney. The highest residue detected was 0.2 mg/kg spinosad in perirenal fat 7 days after generous treatment of a sheep with a large fly strike. Residues of spinosad in fat peaked 3 to 7 days after treatment and 1 to 3 days after treatment in liver and kidney. Conclusion These studies present a realistic worst-case in struck sheep and at the highest dose studied, equivalent to 5.8 mg spinosad per kg body weight, the maximum residue detected of 0.2 mg/kg in peri-renal fat was 20% of the Australian maximum residue limit. Muscle, liver and kidney residues of spinosad were also below the Australian maximum residue limits at all times.

Production of fibrolytic enzymes by Aspergillus japonicus C03 using agro-industrial residues with potential application as additives in animal feed

Solid-state fermentation obtained from different and low-cost carbon sources was evaluated to endocellulases and endoxylanases production by Aspergillus japonicus C03. Regarding the enzymatic production the highest levels were observed at 30 degrees C, using soy bran added to crushed corncob or wheat bran added to sugarcane bagasse, humidified with salt solutions, and incubated for 3 days (xylanase) or 6 days (cellulase) with 70% relative humidity. Peptone improved the xylanase and cellulase activities in 12 and 29%, respectively. The optimum temperature corresponded to 60 degrees C and 50-55 degrees C for xylanase and cellulase, respectively, both having 4.0 as optimum pH. Xylanase was fully stable up to 40 degrees C, which is close to the rumen temperature. The enzymes were stable in pH 4.0-7.0. Cu(++) and Mn(++) increased xylanase and cellulase activities by 10 and 64%, respectively. A. japonicus C03 xylanase was greatly stable in goat rumen fluid for 4 h during in vivo and in vitro experiments.