Effects of various surfactants and solutions on the morphology of polyaniline composite and nanocomposite

Polyaniline composite and nanocomposite were generated in aqueous and aqueous/nonaqueous media by using ammonium peroxydisulfate as an oxidant in the presence of various surfactants such as sodium dodecylbenzenesulfonate, poly(vinyl alcohol), hydroxypropylcellulose, poly(ethylene glycol), and poly(vinyl pyrrolidone). The results indicated that the morphology and size of the particles were dependent on the type of surfactant and solution used. The size range of the particles and nanoparticles was about 75–160 nm. The molecular structure was studied by using Fourier‐transform infrared spectroscopy,and the results showed that the intensities of the peaks were dependent on the nature of the surfactant. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

The formation of hydrophobic and corrosion resistant surfaces on copper and bronze by treatment in myristic acid

The surface of freshly etched copper and bronze samples was modified by immersion in ethanol solutions of myristic (tetradecanoic) acid. Modification resulted in the formation of hydrophobic layers with contact angles up to 141°. Two kinds of surface structure were observed. The modified surface of copper was covered by a uniform layer containing nano-grains or knitted-like structure, whereas the modified surface of bronze was covered by a layer with lamellate patterns and nano-grains. The corrosion properties of bare and modified copper and bronze surfaces were tested by potentiodynamic polarization experiments in 0.014 M Na₂SO₄ + 0.024 M NaHCO₃ solution. The deduced effectiveness of corrosion inhibition by the modified layers on copper and bronze was up to 97 and 68%, respectively. Modification of the surface by immersion in an ethanol solution of myristic acid appears to be a promising treatment for improving the corrosion resistance of copper. The same treatment was not very effective when used on bronze.     

Treg-Resistant Cytotoxic CD4+ T Cells Dictate T Helper Cells in Their Vicinity: TH17 Skewing and Modulation of Proliferation

Cytotoxic CD4⁺ T cells (CD4 CTL) are terminally differentiated T helper cells that contribute to autoimmune diseases, such as multiple sclerosis. We developed a novel triple co-culture transwell assay to study mutual interactions between CD4 CTL, conventional TH cells, and regulatory T cells (Tregs) simultaneously. We show that, while CD4 CTL are resistant to suppression by Tregs in vitro, the conditioned medium of CD4 CTL accentuates the suppressive phenotype of Tregs by upregulating IL-10, Granzyme B, CTLA-4, and PD-1. We demonstrate that CD4 CTL conditioned medium skews memory TH cells to a TH17 phenotype, suggesting that the CD4 CTL induce bystander polarization. In our triple co-culture assay, the CD4 CTL secretome promotes the proliferation of TH cells, even in the presence of Tregs. However, when cell−cell contact is established between CD4 CTL and TH cells, the proliferation of TH cells is no longer increased and Treg-mediated suppression is restored. Taken together, our results suggest that when TH cells acquire cytotoxic properties, these Treg-resistant CD4 CTL affect the proliferation and phenotype of conventional TH cells in their vicinity. By creating such a pro-inflammatory microenvironment, CD4 CTL may favor their own persistence and expansion, and that of other potentially pathogenic TH cells, thereby contributing to pathogenic responses in autoimmune disorders.     

Regulation of Anti-Apoptotic SOD2 and BIRC3 in Periodontal Cells and Tissues

The aim of the study was to clarify whether orthodontic forces and periodontitis interact with respect to the anti-apoptotic molecules superoxide dismutase 2 (SOD2) and baculoviral IAP repeat-containing protein 3 (BIRC3). SOD2, BIRC3, and the apoptotic markers caspases 3 (CASP3) and 9 (CASP9) were analyzed in gingiva from periodontally healthy and periodontitis subjects by real-time PCR and immunohistochemistry. SOD2 and BIRC3 were also studied in gingiva from rats with experimental periodontitis and/or orthodontic tooth movement. Additionally, SOD2 and BIRC3 levels were examined in human periodontal fibroblasts incubated with Fusobacterium nucleatum and/or subjected to mechanical forces. Gingiva from periodontitis patients showed significantly higher SOD2, BIRC3, CASP3, and CASP9 levels than periodontally healthy gingiva. SOD2 and BIRC3 expressions were also significantly increased in the gingiva from rats with experimental periodontitis, but the upregulation of both molecules was significantly diminished in the concomitant presence of orthodontic tooth movement. In vitro, SOD2 and BIRC3 levels were significantly increased by F. nucleatum, but this stimulatory effect was also significantly inhibited by mechanical forces. Our study suggests that SOD2 and BIRC3 are produced in periodontal infection as a protective mechanism against exaggerated apoptosis. In the concomitant presence of orthodontic forces, this protective anti-apoptotic mechanism may get lost.     

Low-cost synthesis of nano-hydroxyapatite from carp bone waste: Effect of calcination time and temperature

The aim of this study was to synthesize Hydroxyapatite (HA) from carp bone waste by calcination treatment. The effects of calcination temperature and time on crystallite size, crystallinity%, powder size and morphology, formed phases, and Ca/P ratio were analyzed. The XRD analyses indicated that for 1 h calcination time, HA was the only phase produced at all temperatures. However, for 5 h calcination time, temperatures other than 700ºC resulted in formation of TCP+HA. The HA obtained at 700ºC at both times had less crystallinity compared to other temperatures. Crystallite size increased by increase in temperature at 1 h calcination time. The smallest and largest particulate sizes were obtained at 800ºC for 1 h and 900ºC for 5 h, respectively. The Ca/P ratio close to theoretical value (1.67) was obtained for 5 h calcination time. Finally, the results showed the usefulness of the methodology used in natural HA production that can be used in orthopedics and dentistry.     

The size and effort estimates in iterative development

The quick delivery of a functionally truncated product is one of the most common results in iterative development, and has become the predominant development approach. One of its drawbacks is the appearance of incomplete artifacts between iterations. Consequently, well-known size-estimation methods can not be used in iterative development. This paper addresses the problem of size estimation in iterative development. We present a novel approach that enables early size estimation using Unified Modeling Language (UML) artifacts. The approach incorporates self-improvement steps that increase the estimation accuracy in subsequent iterations. The demonstration of its applicability and research results are also presented. The results anticipate the possibility of a significant improvement in size and effort estimates by applying the approach presented here.     

Removal of methylene blue dye from aqueous solutions by a new chitosan/zeolite composite from shrimp waste: Kinetic and equilibrium study

The adsorption of methylene blue dye (MBD) from aqueous solutions was investigated using a new composite made up of shrimp waste chitosan and zeolite as adsorbent. Response surface methodology (RSM) was used to optimize the effects of process variables, such as contact time, pH, adsorbent dose and initial MBD concentration on dye removal. The results showed that optimum conditions for removal of MBD were adsorbent dose of 2.5 g/L and pH of 9.0, and initial MBD concentration of 43.75 mg/L and contact time of 138.65 min. The initial concentration of dye had the greatest influence on MBD adsorption among other variables. The experimental data were well fitted by the pseudo-second order kinetic model, while the Freundlich isotherm model indicated a good ability for describing equilibrium data. According to this isotherm model, maximum adsorption capacity of the composite was 24.5 mg/g. Desorption studies showed that the desorption process is favored at low pH under acidic conditions.     

Liquid uptake in Scots pine sapwood and hardwood visualized and quantified by neutron radiography

Non-destructive neutron radiography is used to study the different processes of liquid transport in Scots pine sapwood and heartwood. The spatial and temporal changes in moisture content and saturation degree, measured at high resolution, are provided for water uptake in longitudinal, radial and tangential directions. Liquid uptake in sapwood, compared to in heartwood, is found to be faster and more homogeneous. Latewood cells are the preferential pathways for longitudinal and tangential uptake in both sapwood and heartwood resulting in strongly non-uniform water fronts. In radial uptake, water accumulates first in the border between growth layers. While the moisture content profiles vary strongly between earlywood and latewood layers, the corresponding swelling strain profiles change smoothly due to the mechanical interaction between the different layers. Long term experiments in laboratory show three phases of uptake: a first fast phase, a second slower phase and a third phase reaching capillary saturation. The main difference between sapwood and heartwood uptake takes place in the first phase when liquid is mainly transported in the lumen, until moisture reaches the top of the sample. After that, both wood types behave similarly, uptake is followed by a slower adsorption in the wood cell walls and liquid redistribution in perpendicular to the uptake direction until the sample is almost totally saturated. These findings are of interest for future studies on durability and treatability of pine sapwood and hardwood.