The use of PEEK nanorod arrays for the fabrication of nanoporous surfaces under high temperature: SiN(x) example

Large area silicon nitride (SiN(x)) nanoporous surfaces are fabricated using poly(ether-ether-ketone) (PEEK) nanorod arrays as a template. The procedure involves manipulation of nanoporous anodic aluminum oxide (AAO) templates in order to form an ordered array of PEEK nanopillars with high temperature resistant characteristics. In this context, self-ordered AAO templates are infiltrated with PEEK melts via the "precursor film" method. Once the melts have been crystallized in the porous structure of AAO, the basis alumina layer is removed, yielding an ordered array of PEEK nanopillars. The resulting structure is a high temperature and chemical resistant polymeric nanomold, which can be utilized in the synthesis of nanoporous materials under aggressive conditions. Such conditions are high temperatures (up to 320 °C), vacuum, or extreme pH. For example, SiN(x) nanopore arrays have been grown by plasma enhanced chemical vapor deposition at 300 °C, which can be of interest as mold for nanoimprint lithography, due to its hardness and low surface energy. The SiN(x) nanopore array portrays the same characteristics as the original AAO template: 120 nm diameter pores and an interpore distance of 430 nm. Furthermore, the aspect ratio of the SiN(x) nanopores can be tuned by selecting an AAO template with appropriate conditions. The use of PEEK as a nanotemplate extends the applicability of polymeric nanopatterns into a temperature regime up to now not accessible and opens up the simple fabrication of novel nanoporous inorganic surfaces.     

A medicinal-chemistry-guided approach to selective and druglike sigma 1 ligands

Based on a medicinal-chemistry-guided approach, three novel series of druglike cycloalkyl-annelated pyrazoles were synthesized and display high affinity (pKi>8) for the sigma1 receptor. Structure-affinity relationships were established, and the different scaffolds were optimized with respect to sigma1 binding and selectivity versus the sigma2 receptor and the hERG channel, resulting in selective compounds that have Ki values (for sigma1) in the subnanomolar range. Selected compounds were screened for cytochrome P450 inhibition (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4), metabolic stability (rat and human liver microsomes), and cell-membrane permeability (Caco-2). They showed favorable in vitro ADME properties as well as favorable calculated druglike and experimental physicochemical properties. Furthermore, compounds 7 f and 17 a, for example, displayed high selectivity (affinity) for the sigma1 receptor against a wide range of other receptors (>60). With these valuable tool compounds in hand, we are further exploring the role of the sigma1 receptor in relevant animal models corresponding to such medicinal indications as drug abuse, pain, depression, anxiety, and psychosis.     

Damage in cement pastes exposed to MgCl<Subscript>2</Subscript> solutions

Magnesium chloride (MgCl₂) reacts with cement pastes resulting in calcium leaching and the formation of calcium oxychloride, which can cause damage. This paper examines the damage in different cement pastes exposed to MgCl₂ solutions. Volume change measurement and low temperature differential scanning calorimetry are used to characterize the formation of calcium oxychloride. Thermogravimetric analysis and X-ray fluorescence are used to quantify calcium leaching from Ca(OH)₂ and C-S-H. The ball-on-three-balls test is used to quantify the flexural strength reduction. Calcium oxychloride can form in cement pastes exposed to MgCl₂ solutions with a (Ca(OH)₂/MgCl₂) molar ratio larger than 1. As the MgCl₂ concentration increases, two-stages of flexural strength reduction are observed in the plain cement pastes, with the initial reduction primarily due to calcium leaching from Ca(OH)₂ and the additional reduction due to the calcium leaching from C-S-H (at MgCl₂ concentrations above 17.5 wt%). For the cement pastes containing fly ash, there is a smaller reduction in flexural strength as less Ca(OH)₂ is leached, while no additional reduction is observed at high MgCl₂ concentrations due to the greater stability of C-S-H with a lower Ca/Si ratio. The addition of fly ash can mitigate damage in the presence of MgCl₂ solutions.     

Selective catalytic reduction of nitric oxide by ammonia over Cu-exchanged Cuban natural zeolites

The catalytic selective reduction of NO over Cu-exchanged natural zeolites (mordenite (MP) and clinoptilolite (HC)) from Cuba using NH₃ as reducing agent and in the presence of excess oxygen was studied. Cu(II)-exchanged zeolites are very active catalysts, with conversions of NO of 95%, a high selectivity to N₂ at low temperatures, and exhibiting good water tolerance. The chemical state of the Cu(II) in exchanged zeolites was characterized by H₂-TPR and XPS. Cu(II)-exchanged clinoptilolite underwent a severe deactivation in the presence of SO₂. However, Cu(II)-exchanged mordenite not only maintained its catalytic activity, but even showed a slight improvement after 20 h of reaction in the presence of 100 ppm of SO₂.     

CoordMaude: Simplifying Formal Coordination Specifications of Cooperation Environments

Developing concurrent applications in cooperative environments is an arduous task. This is mainly due to the fact that it is very difficult to specify the synchronized interaction between the entities composing the system. Using coordination models makes this task easier. The latest trends in this area suggest that to manage the successful implementation of complex systems, coordination models must support some key features regarding the coordination constraints: their separated specification, their unanticipated evolution and their dynamic change. However, supporting these features is not only a technical challenge: it must be also guaranteed that the application of a separately specified coordination pattern to a set of encapsulated entities, or the change of the coordination constraints in an already running software system will not produce semantic errors. This is just the problem focused in this paper. In particular, a method for generating formal interpretable specifications reproducing coordinated environments is presented. The method is based on the Coordinated Roles coordination model and makes use of Maude as a formal language. The benefits obtained are: (i) easy specification using the coordination model syntax, (ii) automatic generation of the corresponding formal specification and (iii) simulation of system behaviour.     

Validation of strain invariant failure analysis in an open hole off-axis specimen

We present a model that incorporates the effect of uncertainty in the microstructure of composite systems in failure analysis. The method involves a recently developed micromechanical enhancement model to integrate the effect of variability in the fiber volume fraction. The model determines the range of failure angles in an open hole off-axis specimen and the uncertainty in the critical effective shear strain in the matrix phase at failure due to uncertainties in the fiber volume fraction. A Bayesian methodology is used for model validation and the Bayes factor metric is used to quantify the confidence in the model prediction.     

New progress in the extraction and identification of Mexican cochineal (Dactylopius coccus) in fresh dyed wool and dyed wool with artificially accelerated aging and color description

The main purpose of this study was to determine if a method developed in the laboratory by HPLC-ESI-QToF was able to identify the characteristic compounds of the Mexican cochineal (Dactylopius coccus) in freshly dyed wool fiber and following an artificially accelerated aging process. Wool fibers were dyed with various formulations of popular interest (red-orange, Mexican red, cochineal red, and purple). These formulations are currently used by indigenous communities in the south of Mexico. Some dyed wools were aged in an UV chamber, in order to simulate the deterioration that a fiber dyed in a previous time could have. Notable results were the identification of the main component, carminic acid, and the respective biomarkers of the Mexican cochineal (dcII, dcIV, and dcVII) with a small amount of sample and in a short time, in three of the four formulations before and after aging, thus providing a method that can probably be used for conservation purposes of cultural heritage. It was concluded that when alum is used as a mordant and as a carbonate pH fixer, the fixation of cochineal on the wool is not very strong. This is one of the few works where Mexican cochineal has been studied, simulating the deterioration due to the passage of time in wool samples of different colors with the same natural dye. As a way of describing the color more objectively, the color was measured with the CIE L*A*B* scale in the four formulations of interest, in recently dyed and artificially aged wool.     

Pectin-derived oligosaccharides increase color and anthocyanin content in Flame Seedless grapes

BACKGROUND: Grapes grown in warm weather do not develop a desirable red color and require the use of products to enhance berry color. Pectin‐derived oligosaccharides (PDOs) have been shown to have a role in various responses including plant defense, growth and development. In this work a mixture of PDOs with 3–20 degrees of polymerization was applied to Vitis vinifera cv. Flame Seedless grapes under field conditions and compared to the effects of ethephon (an ethylene‐releasing compound). The effect of treatments on grape color, anthocyanin content and phenylalanine ammonia lyase (PAL) mRNA levels was evaluated. RESULTS: PDOs treatment increased berry color measured by the Color Index of Red Grapes (CIRG) and anthocyanin content, compared to ethephon and untreated berries (control); 1.5, 1 and 0.5 mg mL^?1 PDOs increased berry color by 30%, 27% and 26%, respectively, when compared to control berries. Levels of PAL mRNA accumulating in berries treated with PDOs were elevated within the first 24 h of treatment. CONCLUSIONS: PDOs enhanced the color and anthocyanin content of Flame Seedless grape berries possibly due by the induction of PAL mRNA expression. The results demonstrated that PDOs can be used to improve fruit quality aspects such as berry skin color. Copyright © 2011 Society of Chemical Industry