Bilayered phospholipid micelles and capillary electrophoresis: a new additive for electrokinetic chromatography

Phospholipid micelles and bilayered micelles (bicelles) were investigated as a new media for electrokinetic chromatography. The benefit to using these additives for micellar electrokinetic chromatography (MEKC) is the potential of a simple bilayer membrane model operated with fast analysis time, and low sample injection volumes. The system is used to separate peptides/protein and is tested with a series of beta-blockers. The results suggest that bicelle electrokinetic chromatography provides selectivity and holds potential as an alternative approach to modeling membrane phenomenon.     

Water‐Developable Poly(2‐oxazoline)‐Based Negative Photoresists

Copoly(2‐oxazoline)‐based photoresists are prepared from pEtOx₈₀Bu⁼Ox₂₀ and pPhOx₈₀Dc⁼Ox₂₀ , respectively, a tetrathiol, and a photosensitive initiator. It is possible to prepare copoly(2‐oxazoline)s bearing unsaturated side chains in a microwave reactor on a decagram scale in reaction times of 100 min or shorter. UV irradiation of dried polymer films through a quartz mask induces the thiol‐ene reaction in the illuminated areas. Subsequent development of the polymer films in halogen‐free solvents reproduces the negative pattern of the mask with a resolution of 2 μm. The pEtOx₈₀Bu⁼Ox₂₀ ‐derived photoresists can also be developed in water.     

Amidrazones 11. Rearrangement of 1-allyl-substituted-4,5-dihydro-1-methyl-1H-pyrazolium bromides

1-Methyl-2-(2-propenyl)-3-pyrazolidinimine ( 5 ) was obtained by treatment of 3-amino-4,5-dihydro-1-methyl- 1-(2-propenyl)-1H-pyrazolium bromide ( 4 ) with ethanolic sodium ethoxide. Similar treatment of the analogous 2-(2-butenyl) and 2-(3-phenyl-2-propenyl)-substituted salts 12 and 15 gave 1-methyl-2-(1-methyl-2-propenyl)-3- pyrazolidinimine ( 13 ) and 1-methyl-2-(1-phenyl-1-propenyl)-3-pyrazolidinimine ( 16 ) respectively.     

Properties and structure of manganese oxide-coated clay

In the environment, heavy metals are important contaminants that sorb to and accumulate in soils and sediments. Dominant minerals in the subsurface are oxides and clay, which occur as discrete particles and heterogeneous systems; these surfaces can significantly impact the mobility and bioavailability of metals through sorption. To better understand heterogeneous systems, amorphous (hydrous manganese oxide (HMO)) and crystalline manganese oxides (birnessite and pyrolusite) were coated on montmorillonite. However, the montmorillonite substrate potentially inhibited crystallization of the pyrolusite coating, and also resulted in a poorly crystalline birnessite. Mineralogy and morphology of the coated systems suggest an amorphous structure for HMO and uniform coverage for HMO and birnessite coatings; the presence of Si and Al indicates uncoated areas along intraplanar surfaces. The coating surface charge behaved similarly to that of discrete oxides and clay where the pH(znpc) of HMO- and birnessite-coated clay were 2.8 and 3.1, respectively. Surface area of the coated systems increased while the pore size distribution decreased as compared to the external surface area and pores of montmorillonite. X-ray absorption spectroscopy (XAS) revealed the local structural environment of Mn in the HMO- and birnessite-coated clay was consistent with the pure phase oxides: for HMO-coated clay 3.1 atoms of oxygen at 1.89 +/- 0.02 A in the first shell and 2.7 atoms of manganese at 2.85 +/- 0.02 in the second shell; and, for birnessite-coated clay 6 atoms of oxygen at 1.91 +/- 0.02 A in the first shell and 6 atoms of manganese at distance 2.99 +/- 0.02 A in the second shell. Overall, the surface properties suggest that the coating behaves like that of discrete oxides, an important sink for metal contaminants.     

An advanced decision support system for European disaster management: the feature of the skills taxonomy

Central European Journal of Operations Research - Mankind has faced a huge increase in severe natural and man-made disasters worldwide in the last few years. Emergency responders on a strategic,...     

Effect of ammonia addition on suppressing soot formation in methane co-flow diffusion flames

Due to issues surrounding carbon dioxide emissions from carbon-containing fuels, there is growing interest in ammonia (NH₃) as an alternative combustion fuel. One attractive method of burning NH₃ is to co-fire it with hydrocarbons, such as natural gas, and in this case soot formation is possible. To begin understanding the influence of NH₃ on soot formation when co-fired with hydrocarbons, soot volume fractions and mole fractions of gas-phase species were computationally and experimentally interrogated for CH₄ flames with up to 40% NH₃ by volumetric fuel fraction. Mole fractions of gas-phase species, including C₂H₂ and C₆H₆, were measured with on-line electron impact mass spectrometry, and soot volume fractions were obtained via color-ratio pyrometry. The simulations employed a detailed chemical mechanism developed for capturing nitrogen interactions with hydrocarbons during combustion. The results are compared to findings in N₂CH₄ flames, in order to separate thermal and dilution effects from the chemical influence of NH₃ on soot formation. Experimentally, C₂H₂ concentrations were found to decrease slightly for the NH₃CH₄ flames relative to N₂CH₄ flames, and a stronger suppression of C₆H₆ was found for NH₃ relative to N₂ additions. The measured results show a strong suppression of soot with the addition of NH₃, with soot concentrations reduced by over a factor of 10 with addition of up to 20% or more NH₃ by mole fraction. The model satisfactorily captured relative differences in maximum centerline C₂H₂, C₆H₆, and soot concentrations with addition of N₂, but was unable to match measured differences in NH₃CH₄ flames. These results highlight the need for an improved understanding of fuel-nitrogen interactions with higher hydrocarbons to enable accurate models for predicting particulate emissions from NH₃/hydrocarbon combustion.     

Visible Light-Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three-Component Photoredox Reaction

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomolecules. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination.     

Mathematics and science teacher training program improves inquiry practices for teachers

With the call for increasing the level of inquiry-based instruction in mathematics and science classrooms, it is imperative for teacher education programs to prepare teachers with these skills. This study draws from classroom observation data to determine the influence a unique teacher certification program has on key aspects of teacher practice using a series of Kruskal-Wallis and Wilcoxon Rank Sum tests. Findings indicate that teachers participating in the program have a statistically significant level of growth in their use of inquiry practices related to Classroom Culture. In addition, by the fourth semester of their involvement in the program, participating teachers employ higher levels of inquiry instruction than a comparison group of teachers for almost every factor assessed.