Optimization of methods and treatment conditions for studying effects of fatty acids on cell growth

Antiproliferative properties of molecular regulators of lipid metabolism have been increasingly studied during recent years. Discussion is ongoing concerning optimal treatment conditions and assays used for monitoring proliferation and cytotoxicity. The objective of the present work was to optimize methods and treatment conditions used for studying antiproliferative effects of fatty acids and analogs, represented by palmitic acid (PA) and the β-oxidation-restricted fatty acid analog tetradecylthioacetic acid (TTA), in rat (BT4Cn) and human (D54Mg and GaMg) glioma cell lines. Changes in [³H]thymidine incorporation preceded changes in cell number in TTA-treated glioma cell cultures, and the growth inhibition was more significantly expressed by [³H]thymidine incorporation than cell number. Addition of bovine serum albumin decreased cellular fatty acid uptake and reduced the effects of TTA and PA on [³H]thymidine incorporation. Determination of the antiproliferative effect of TTA in BT4Cn cells by MTT conversion and [³H]thymidine incorporation yielded concordant results. TTA-mediated reduction in cell number corresponded to reduction in cellular protein and total DNA content in BT4Cn cells. Reduced growth potential in TTA-treated multicellular D54Mg and GaMg spheroids supported the findings from monolayer cultures. In conclusion, cell density, treatment period, fatty acid administration, and methods for growth determination may profoundly influence the outcome of cell growth experiments. Thus, experimental conditions should be carefully controlled when performing cell growth experiments, and effects on cell growth should preferably be confirmed by different methods. Karl Johan Tronstad and Kjetil Berge contributed equally to this article.     

Water and Solute Movement in Air Pollution Control Residues Measured by Time-Domain Reflectometry

The mobility of pollutants from air pollution control (APC) residues is strongly influenced by its contact with water. This study aims to verify the applicability of time-domain reflectometry (TDR) to infer water and solute movement in situ in an APC residue–compost mixture in a laboratory column. The calibrated dielectric permittivity–volumetric water content relationship (K?θv) for the material shows a distinct plateau at midrange volumetric water contents, which are underestimated by Topp’s K?θv model throughout the studied range. The coating of probes enables a clear TDR signal collection and analysis up to electrical conductivity values of 280?mS?cm?1. Heterogeneities in packing and channel flow in the column are revealed by TDR measurements. Water contents inferred by TDR signal analysis require careful interpretation when used in materials such as APC residues, due to the high amount of water bound in the hydration shells of ions released into the pore water.     

Trajectory planning in the infinity norm for linear control systems

When planning trajectories, a reasonable demand on the generated curves is that they interpolate through given points, or given intervals, at given specified times, or that they go through these points or intervals at times lying in specified time windows. This problem is addressed here as an optimal control problem, minimizing the infinity norm of the inputs of a discretized linear control system since the infinity norm minimization problem arises naturally when doing trajectory planning for both controlled switching systems and non-holonomic robotic systems.     

STEAM DRYLNG OF WOOD FUELS

ABSTRACT

The objective of this work is to investigate some of the important aspects in the design of a steam band dryer for wood fuels. For this purpose the drying of the material in a bench-scale fixed bed dryer has been studied.

Drying times and thermal efficiencies for experiments conducted under different conditions are compared. The investigated materials are soft-and hardwood chips and softwood bark.

The thermal efficiency, the part of the sensible heat which is used during one passage of the steam through the bed, increases with increasing mass load (mass of dry matter per unit area) and with decreasing steam mass flux. At a mass load of 30 kg/m the thermal efficiency is about 0.85 even at steam mass fluxes as high as 0.6 kg/m² s (1.2 m/s). The thermal efficiency proves to be almost independent of pressure and temperature of the steam.

Due to the very inhomogeneous materials the steam mass flow distribution was uneven. This causes a decreased thermal efficiency. When bark     

The Sephadex story

The environment and the circumstances leading to the Sephadex group of products for gel filtration (SEC, size exclusion chromatography) are described. The importance of Porath's and the author's experience from zone electrophoresis is stressed. To be able to get high resolution the technique for packing columns was of decisive importance for electrophoresis. It paved the way for the observation of the separation properties of dextran gels. The synthesis of dextran-based gels at AB Pharmacia and the development of varieties of them for varying applications are described together with the project leading to their marketing in 1959. The work of the author on gel filtration is summarized. The story is based on publication and memory. Aids to the latter have been laboratory notebooks and other documents still in the possession of the author.     

Analytical and self-consistent quantum mechanical model for a surrounding gate MOS nanowire operated in JFET mode

We derive an analytical model for the electrostatics and the drive current in a silicon nanowire operating in JFET mode. We show that there exists a range of nanowire radii and doping densities for which the nanowire JFET satisfies reasonable device characteristics. For thin nanowires we have developed a self-consistent quantum mechanical model to obtain the electronic structure.     

Consumer adoption of RFID-enabled services. Applying an extended UTAUT model

In this article, an extended version of the unified theory of acceptance and use of technology (UTAUT) is applied to explore the significance of various antecedents of acceptance of eight versions of a radio frequency identification (RFID) enabled service. The results show significant influences from performance expectancy, effort expectancy and technology anxiety on attitude to use RFID-enabled services, while facilitating conditions and attitude to use both have significant influences on intention to use the services. Looking into potential moderating influences, gender moderates most of the relationships in the model while age and experience with identification technology do not seem to be relevant moderators. Exploring the potential moderating influence of context experience, experience of the service context is found to moderate some of the relationships in the model. Managerial implications point to the importance of developing useful and user-friendly services and of communicating the user friendliness to potential customers to avoid the potential negative influence of technology anxiety. Service development and market communication should be sensitive to gender and context experience.     

Using enterprise architecture analysis and interview data to estimate service response time

Insights into service response time is important for service-oriented architectures and service management. However, directly measuring the service response time is not always feasible or can be very costly. This paper extends an analytical modeling method which uses enterprise architecture modeling to support the analysis. The extensions consist of (i) a formalization using the Hybrid Probabilistic Relational Model formalism, (ii) an implementation in an analysis tool for enterprise architecture and (iii) a data collection approach using expert assessments collected via interviews and questionnaires. The accuracy and cost effectiveness of the method was tested empirically by comparing it with direct performance measurements of five services of a geographical information system at a Swedish utility company. The tests indicate that the proposed method can be a viable option for rapid service response time estimates when a moderate accuracy within 15% is sufficient.