Non-Isothermal NOx Storage/Release over Manganese Based Traps: Mechanistic Considerations

The NO storage properties of MnO _x /support materials (5–50 wt% MnO _x loading) was experimentally investigated in the presence of O₂ and H₂O between 50 and 700 °C applying a non-isothermal temperature-programmed method. In dependence on MnO _x loading and NO supply, the materials show an intermediate decrease of NO storage capacity between 200 and 300 °C. This effect is caused by decomposition of surface nitrites with release of NO into the gas phase as proved by in situ DRIFT measurement. The interpretation is corroborated by modelling of the underlying adsorption/desorption reaction steps, considering the different thermal stability of nitrite/nitrate surface species.     

Structure-Activity Relationship and Mode-Of-Action Studies Highlight 1-(4-Biphenylylmethyl)-1H-imidazole-Derived Small Molecules as Potent CYP121 Inhibitors

CYP121 of Mycobacterium tuberculosis (Mtb) is an essential target for the development of novel potent drugs against tuberculosis (TB). Besides known antifungal azoles, further compounds of the azole class were recently identified as CYP121 inhibitors with antimycobacterial activity. Herein, we report the screening of a similarity-oriented library based on the former hit compound, the evaluation of affinity toward CYP121, and activity against M. bovis BCG. The results enabled a comprehensive SAR study, which was extended through the synthesis of promising compounds and led to the identification of favorable features for affinity and/or activity and hit compounds with 2.7-fold improved potency. Mode of action studies show that the hit compounds inhibit substrate conversion and highlighted CYP121 as the main antimycobacterial target of our compounds. Exemplified complex crystal structures of CYP121 with three inhibitors reveal a common binding site. Engaging in both hydrophobic interactions as well as hydrogen bonding to the sixth iron ligand, our compounds block a solvent channel leading to the active site heme. Additionally, we report the first CYP inhibitors that are able to reduce the intracellular replication of M. bovis BCG in macrophages, emphasizing their potential as future drug candidates against TB.     

Dissociation of 19F and fluorescence signal upon cellular uptake of dual-contrast perfluorocarbon nanoemulsions

Magnetic Resonance Materials in Physics, Biology and Medicine - Perfluorocarbon nanoemulsions (PFCs) tagged with fluorescence dyes have been intensively used to confirm the in vivo 19F magnetic...     

Relationship between perceived problem‐solving skills and academic performance of novice learners in introductory programming courses

Past research has shown that student problem‐solving skills may be used to determine student final exam performance. This study reports on the relationship between student perceived problem‐solving skills 1 1 Henceforth, for brevity, we drop the word “perceived” in “student perceived problem‐solving skills” and use either “student perceived problem solving” or simply “student PSS.”
and academic performance in introductory programming, in formative and summative programming assessment tasks. We found that the more effective problem solvers achieved better final exam scores. There was no significant difference in formative assessment performances between effective and poor problem solvers. It is also possible to categorize students on the basis of problem‐solving skills, in order to exploit opportunities to improve learning around constructivist learning theory. Finally, our study identified transferability skills and the study may be extended to identify the impact of problem solving transfer skills on student problem solving for programming.     

Eddy current effects on a clinical 7T-68 cm bore scanner

Introduction  

Eddy currents induced by switching of magnetic field gradients can lead to distortions in short echo-time spectroscopy or diffusion weighted imaging. In small bore magnets, such as human head-only systems, minimization of eddy current effects is more demanding because of the proximity of the gradient coil to conducting structures.     

Fusion prevents the redundant signals effect: Evidence from stereoscopically presented stimuli.

In a simple reaction time (RT) experiment, visual stimuli were stereoscopically presented either to one eye (single stimulation) or to both eyes (redundant stimulation), with brightness matched for single and redundant stimulations. Redundant stimulation resulted in two separate percepts when noncorresponding retinal areas were stimulated, whereas it resulted in a single fused percept when corresponding areas were stimulated. With stimulation of noncorresponding areas, mean RT was shorter to redundant than to single stimulation, replicating the redundant signals effect (RSE) commonly found with visual stimuli. With stimulation of corresponding areas, however, no RSE was observed. This suggests that the RSE is driven by the number of percepts rather than by the number of stimulated receptors or sensory organs. These results are consistent with previous findings in the auditory modality and have implications for models of the RSE. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Farm-Worker Housing in South Africa: An Evaluation of an Off-Farm Housing Project

Although farm-worker housing has been neglected in South Africa historically, new policy, tabled in 2004, specifically targets the constraints that have been hampering delivery in rural areas. While either on- or off-farm farm-worker housing is envisioned, constraints with regard to on-farm housing and service provision, such as the prerequisite of security of tenure, prevent generalised delivery to the rural population, despite the fact that ESTA provides for security of tenure under certain conditions. There is a need to upgrade the living conditions of people on farms where they are currently residing, in order to ensure the right to adequate shelter as envisioned by the Constitution. However, under current legislation tenure rights must first be secured before such action can be taken. Research on an off-farm housing project in Bothaville was conducted in order to determine the sustainability of this approach, while simultaneously assessing the broader housing policy context, with a view to making policy recommendations.