Laser ablation patterning by interference induces directional cell growth

Laser-patterning by interference is a method to introduce micropatterns on the surface of TXL and TXB, which were shown to have an effect on the L929 growth. In this experiment, we have produced collagen-coated and laser-patterned TXL and TXB with different dimensions; the groove width of the line patterns varied approximately from 1.2 /spl mu/m to 9.7 /spl mu/m, ridge depth varied from 0.4 /spl mu/m to 1.3 /spl mu/m, and the groove depth varied between 0.4 /spl mu/m and 1.3 /spl mu/m. Therefore, a homogeneous smooth surface was achieved, and that L929 growth was only affected by the different dimensions of the line patterns. All the laser-patterned TXL and TXB have shown inducing different degrees of directional growth of L929 that the cells grew in the direction aligning the microgrooves. However, the different widths of the microgrooves were demonstrated to play an important role in determining cell morphology and growth orientation. For example, cells were elongated when they grew on the narrower widths, which were 1.26 /spl mu/m, 1.91 /spl mu/m, and 5.04 /spl mu/m while cells tended to be triangular when grew on wider width about 9.76 /spl mu/m. In addition, L929 might grow only on the top of the laser-patterns attaching the ridges when the groove widths were narrow, but might grow into the microgrooves when the width went beyond 5.04 /spl mu/m.     

Cationic silica nanoparticles as gene carriers: synthesis, characterization and transfection efficiency in vitro and in vivo

The potential of cationic SiO2 nanoparticles was investigated for in vivo gene transfer in this study. Cationic SiO2 nanoparticles with surface modification were generated using amino-hexyl-amino-propyltri-methoxysilane (AHAPS). The zeta potential of the nanoparticles at pH = 7.4 varied from -31.4 mV (unmodified particles; 10 nm) to +9.6 mV (modified by AHAPS). Complete immobilization of DNA at the nanoparticle surface was achieved at a particle ratio of 80 (w/w nanoparticle/DNA ratio). The surface modified nanoparticle had a size of 42 nm with a distribution from 10-100 nm. The ability of these particles to transfect pCMVbeta reporter gene was tested in Cos-1 cells, and optimum results were obtained in the presence of FCS and chloroquine at a particle ratio of 80. These nanoparticles were tested for their ability to transfer genes in vivo in the mouse lung, and a two-times increase in the expression levels was found with silica particles in comparison to EGFP alone. Very low or no cell toxicity was observed, suggesting silica nanoparticles as potential alternatives for gene transfection.     

A model to study c-myc and v-H-ras induced prostate cancer progression in the Copenhagen rat

Normal rat prostate epithelial cells (EPYP-1) were isolated and immortalized with the Simian Virus-40 (SV40) large T-antigen, and transfected with the v-H-ras (EPYP-1-ras) and the c-myc oncogenes (EPYP-1-myc; EPYP-1-ras-myc) to serially create a step-wise model of tumor development in the rat prostate. Pronounced morphological differences were observed between EPYP-1 and the transfected sublines. The immortal epithelial cells (EPYP-1) maintained a cuboidal shape with orderly, contact mediated inhibition of growth. Oncogene transfected clones displayed a spindle shaped structure with multiple overlapping pseudopodia. Transfected cells also exhibited a greater degree of dysplasia, loss of contact inhibition growth and the upregulation of an epithelial tumor marker, cytokeratin-18. All cells exhibited anchorage independent and androgen independent growth. In vivo, EPYP-1 cells and EPYP-1-myc and formed slowly growing non-metastatic, benign tumors in immune compromised mice, while EPYP-1-ras and EPYP-1-ras-myc transfected cells produced rapidly growing, malignant tumors in similar animals. This model augments the hypothesis that tumor initiation and progression can be caused by as few as two discrete genetic events. In addition, the "normal" rat prostate epithelium and transfected daughter cell lines represent a tumor model system with distinct, well understood genetic alterations: activation of ras and myc. This model will be a valuable addition to the current cell lines used in the investigation of prostate cancer carcinogenesis.     

Estimation of Volumetric Oxygen Concentration in a Marine Environment with an Autonomous Underwater Vehicle

Dissolved oxygen (DO) concentration is a key indicator of the health and productivity of an aquatic ecosystem. This paper presents a new method for high‐resolution characterization of DO as a function of both space and time. The implementation of a new oxygen optode in an Iver2 autonomous underwater vehicle (AUV) is described, which enables the system to measure both absolute oxygen concentration and percentage saturation. Also described are details of AUV missions in Hopavågen Bay, Norway, which consisted of a series of repeated undulating lawnmower patterns that covered the bay. Through offline postprocessing of data, sensor characteristic models were developed, as well as a 3D lattice time series model. The model was constructed by estimating DO at each 3D lattice node location using a 1D Kalman filter that fused local measurements obtained with the AUV. By repeating model construction for several missions that spanned 24 h, estimates of DO as a function of space and time were calculated. Results demonstrated (1) the AUVs ability to repeatedly gather high‐spatial‐resolution data (2) significant spatial and temporal variation in DO in the water body investigated, and (3) that a 3D model of DO provides better estimates of total DO in a volume than extrapolating from only a single 2D plane. Given the importance of oxygen within an ecosystem, this new method of estimating the quantity of DO per volume has the potential to become a reliable test for the health of an underwater ecosystem. Also, it can be refined for detecting and monitoring a range of soluble gases and dispersed particles in aquatic environments, such as dissolved O₂ and CO₂ around production facilities such as fish farms, or dispersed hydrocarbons and other pollutants in fragile ecosystems. © 2012 Wiley Periodicals, Inc.     

Dämpfung erzwungener Schwingungen durch ein angekoppeltes System

Zusammenfassung Ein bereits h?ufig angewendetes Mittel, unerwünschte Schwingungen zu beseitigen oder zu schw?chen, besteht in der Anwendung gekoppelter Schwingmassen. Bei der Konstruktion von Drehschwingungsd?mpfern oder bei der Bek?mpfung von Fundamentschwingungen ist bisher von diesem Mittel weniger Gebrauch gemacht worden, wohl deshalb, weil die Berechnungsgrundlagen zur Bestimmung des jeweils geeigneten Ankopplungssystems nicht genügend klar und durchsichtig sind. Nachfolgend wird ein Verfahren gegeben und an einem Beispiel erl?utert, wie die günstigsten Bedingungen für ein anzukoppelndes System ermittelt werden k?nnen. VDI Mitteilung der Abtlg. Maschinenbau des Staatl. Materialprüfungsamtes Berlin-Dahlem     

Rheological and mechanical properties of poly(vinyl chloride)/chlorinated poly(vinyl chloride) miscible blends

The properties of poly(vinyl chlorlde)/ehlorinated poly(vinyl chloride) (61.6 percent C1) blends, prepared by melt and solution blending, were measured by various tests. Based on the chlorinated poly(vinyl chloride) (CPVC) composition, percent chlorine, and mole percent CC1₂ groups, these blends were expected to show intermediate properties between miscible and immiscible systems. Indicative of miscible behavior were the single glass transition temperatures over the entire composition range for both melt and solution blended mixtures. A single phase was also indicated by transmission electron microscopy. However, the yield stress showed a minimum value less than either of the pure components in the 50 to 75 percent CPVC range, which is characteristic of two-phased systems. Specific volume, glass transition temperature, and heat distortion temperature were linear with binary composition. The storage modulus showed a small maximum, suggesting a weak interaction between the two miscible polymers. Heats of melting for the residual PVC crystallinity were also less than expected from linear additivity. At 160°C and 210°C, the logarithm of the complex viscosity was essentially linear with volume fraction of CPVC, except for a very slight decrease in the 50 to 75 percent CPVC range, which may have been a result of lower crystallinity. At 140°C, the complex viscosity of the CPVC was less than that of PVC owing to the higher crystallinity of the latter. The viscosities were similar at 160°C, but at 210°C, where most of the crystallites had melted, the complex viscosity of the CPVC was higher because of its higher glass transition temperature.     

The Globally Competent Engineer: Working Effectively with People Who Define Problems Differently

This paper offers and tests an approach to conceptualizing the global competency of engineers. It begins by showing that the often‐stated goal of working effectively with different cultures is fundamentally about learning to work effectively with people who define problems differently. The paper offers a minimum learning criterion for global competency and three learning outcomes whose achievement can help engineering students fulfill that criterion. It uses the criterion to establish a typology of established methods to support global learning for engineering students. It introduces the course, Engineering Cultures, as an example of an integrated classroom experience designed to enable larger numbers of engineering students to take the critical first step toward global competency, and it offers a test application of the learning criterion and outcomes by using them to organize summative assessments of student learning in the course.     

Improved Mixing,Granulation and Drying of Highly Energetic Pyromixtures

A safer and more efficient method of mixing, granulating and drying (MIGRAD) highly energetic (UN 1.1) pyrotechnic composition will be reported. The process uses a MIGRAD mixer/granulator that was tailored to mix, granulate and dry a pyrotechnic material (20-40 lb) within a single mixing chamber. Features of the process include remote loading and unloading, reduced solvent, shortened mixing cycle (40 min), infinitely variable speed control of mixing and granulating impellers, built-in state-of-the-art fire detection/suppression (UV-50 ms, IR-10 ms), explosion venting, heated-chamber, vacuum drying, remote/programmable controls, and remote mixer cleanup using energy of the mixer. The mixing process will be evaluated for preparation of some 24 pyrotechnic compositions for five Arsenals/Ammo Loading Plants. Hazards Classification Safety Data Sheets were prepared for the 24 pyrotechnic compositions and will be reported along with resultant physical properties of the completed compositions.     

Computational fluid dynamics of nanoparticle disposition in the airways: mucus interactions and mucociliary clearance

Interactions of nanoparticles with respiratory fluids such as airway mucus are currently under investigation and are involved in a variety of applications. The clearance processes of those nanoparticles are still not fully understood. This study presents an approach to describe deposition, sedimentation and clearance of nanoparticles within mucus with numerical and analytical models: Particle deposition as well as motility, sedimentation and clearance were simulated with Computational Fluid Dynamics (CFD) and described analytically. Furthermore mucus plasticity as pathway for complex particle translocation was simulated using grid-free CFD methods. We could demonstrate that fluid dynamics strongly influence the fate of deposited nanoparticles in mucus: Sedimentation, impaction and diffusion were shown to be unlikely to contribute to particle translocation. However, intrinsic plasticity of mucus slabs and collision of such slabs may enhance particle translocation towards the pulmonary epithelium.