mTOR Signaling and Potential Therapeutic Targeting in Meningioma

Meningiomas are the most frequent primary tumors arising in the central nervous system. They typically follow a benign course, with an excellent prognosis for grade I lesions through surgical intervention. Although radiotherapy is a good option for recurrent, progressive, or inoperable tumors, alternative treatments are very limited. mTOR is a protein complex with increasing therapeutical potential as a target in cancer. The current understanding of the mTOR pathway heavily involves it in the development of meningioma. Its activation is strongly dependent on PI3K/Akt signaling and the merlin protein. Both factors are commonly defective in meningioma cells, which indicates their likely function in tumor growth. Furthermore, regarding molecular tumorigenesis, the kinase activity of the mTORC1 complex inhibits many components of the autophagosome, such as the ULK1 or Beclin complexes. mTOR contributes to redox homeostasis, a vital component of neoplasia. Recent clinical trials have investigated novel chemotherapeutic agents for mTOR inhibition, showing promising results in resistant or recurrent meningiomas.     

Adhesion between thermoplastic elastomers and polyamide-12 with different glass fiber fractions in two-component injection molding

The usage of thermoplastic elastomers (TPEs) is increasing, and integrated hard-soft parts can be mass produced by two-component injection molding (or sequential molding). A key property of such parts, the adhesion between the two materials, is the topic of this study. The hard part (the first molded component) in this study was polyamide-12 with 0 to 50 wt% glass fibers (PA12-GF). As the second component, two TPEs were used: a vulcanized TPE and a styrenic TPE, both modified for adhesion to polyamides. The adhesion, assessed by 90° peel tests, increased with increasing melt temperatures and TPE injection rate, while it decreased with increasing glass fiber fraction in the PA12-GF. Based on characterization of cross-sections and fiber distributions near the interface, we propose some hypotheses for the effect of fiber fraction on the fusion between PA12-GF and TPE. These hypotheses involve the near-surface properties of the PA12-GF materials, microstructure, thermo-mechanical properties, and thermal properties. A direct effect of increasing the glass fiber fraction, that is, a reduction in adhesion as more fibers are present at the interface, does not seem to be a major effect, since few fibers are in direct contact with the TPE for any fiber fraction.     

Pulsed NMR of monolayer and near-monolayer films of 3He adsorbed on Grafoil at low temperatures

Pulsed NMR measurements at 30 MHz of near-monolayer coverages of ³He on Grafoil have been made between 4.2 and 0.1 K. The time constants of the free induction decay indicate that below 4.2 K the mobility of ³He in an exact monolayer is smaller than that at lower coverages or at coverages above one monolayer, in agreement with the results found by Hegde and Daunt, by Cowan and co-workers, and by Rollefson. Furthermore, in spite of rf heating of the sample, we were able to conclude that the mobility of ³He in nearmonolayers films decreases as the temperature is decreased below 4.2 K. At 4K and 30MHz our measurements give T₁ = 1 ± 0.3 sec for coverages between 0.6 and 1.35 monolayers. This is in agreement with previous work.Supported by the National Science Foundation.     

Long term stability of germanium films

The electrical resistance of thin germanium films is sensitive to changes in the ambient atmosphere. Both reversible and irreversible changes are observed. Here we discuss their origin and mechanism. The irreversible effect is apparently largely due to oxidation at room temperature, while the reversible effect is associated with adsorption-desorption of polar gas species. Both chemical protection (passivation) and electrostatic screening are necessary to provide long term stability of germanium films.     

From crisis to development--analysis of air traffic control work processes

In this study an intervention to improve work processes in air traffic control (ATC) is evaluated. The background was the Finnish air traffic controllers’ strike of 1999. The old ways of thinking and acting did not support development of ATC prompting a need for a new kind of working culture in the organisation. Several actions were started. In one of these, ATC work processes were modelled by personnel and development plans concerning work were delivered to top management. Different actors (management, trade union, stakeholders) were interviewed before (n = 16) and after the project (n = 7). The intervention supported systematic co-operation between different actors in the organisation. However, a follow-up revealed that only a few participants had adopted the idea of continuous work development. Mastery of human factors is crucial in a high reliability work environment such as ATC. But how is the analytical and co-operative aspect kept alive in an organisation that is run by strict international regulation and has a strong technical competence, but is not that strong in collaborative and human aspects?     

Benzene: a secondary pollutant formed in the three-way catalyst

Benzene emissions from a relevant proportion of today's gasoline-driven passenger cars and light-duty vehicles can increase by up to 2 orders of magnitude when driving at high engine load (e.g., on highways). Under such conditions, post-catalyst benzene levels exceeded those found pre-catalyst. As a consequence, formation of benzene in the catalyst was postulated. To further reduce ambient air concentrations of benzene,these critical operating conditions must be carefully avoided. Here, we report in detail to what extent and at what operating conditions catalyst-induced benzene and toluene formation can occur. For that purpose, a EURO-1 passenger car (1.8 L, model year 1995)fulfilling the valid regulations, equipped with a new, two-layered, Pd-CeO2-Al2O3/Rh-ZrO2-Al2O3 three-way catalyst was operated at steady state on a chassis dynamometer at 100, 125, and 150 km/h at variable air to fuel ratios. Pre- and post-catalyst exhaust gas concentrations of benzene, toluene, C2-, and C3-benzenes were monitored at a time resolution of 0.5 Hz by means of chemical ionization mass spectrometry. A net benzene formation window, ranging from pre-catalyst exhaust gas temperatures of 600-730 degrees C and lambda-values of 0.83-0.95, with a pronounced minimum at 0.87, was observed. Dealkylation reactions of aromatic hydrocarbons are assumed to be the major pathway leading to benzene.