Transparent thin thermoplastic biochip by injection-moulding and laser transmission welding

Recently microfluidic devices have emerged as a viable technology for the miniaturization of high throughput tools for analytical tasks related to structural biology such as screening of crystallization conditions and structural analysis. This work reports the manufacture of microfluidic chips in transparent thermoplastic polymers [poly(methylmethacrylate) (PMMA), and cyclic olefin copolymer (COC)] using two complementary technologies, injection moulding for the fabrication of the fluidic level and laser transmission welding for the sealing of the cover. A steel mould insert was produced by laser micro caving using a solid state laser radiation source (Nd:YAG, wavelength 1,064 nm). Fluidic chips of ~670 μm thickness comprising channels of 50 μm depth and width down to 50 μm were injection moulded in PMMA and COC. Joining of transparent thin cover film to the micro-injected fluidic level was performed by laser transmission welding using high power diode laser radiation (wavelength 940 nm) and an intermediate thin absorbing layer with a thickness of about several nanometers.     

Nanostructured titania powders by hydrothermal processing and spray drying

Sol-gel precipitates of titania were prepared from organometallic precursors, followed by hydrothermal crystallization and spray drying into spherical, micron-size nanostructured granules that were characterized by X-ray diffraction, nitrogen adsorption, and microscopy. A systematic investigation of the effect of hydrothermal processing conditions on the physical properties of the granules was carried out. When the hydrothermal processing time was increased, product granules exhibited larger anatase crystallite size and improved thermal stability in pore structure and phase composition. Increasing the hydrothermal processing temperature retarded crystallite growth and increased the anatase-to-rutile transformation temperature.     

The meaning(s) of conditionals: Conditional probabilities, mental models, and personal utilities.

[Correction Notice: An erratum for this article was reported in Vol 29(6) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2007-16865-001). On page 684, Table 4, all correlations should have been identified as having a pp then q") as indicating a high conditional probability P(q|p). Participants estimated the probability that a given conditional is true (Experiments 1A, 1B, and 3) or judged whether a conditional was true or false (Experiments 2 and 4) given information about the frequencies of the relevant truth table cases. Judgments were strongly influenced by the ratio of pq to p?q cases, supporting the conditional probability account. In Experiments 1A, 1B, and 3, judgments were also affected by the frequency of pq cases, consistent with a version of mental model theory. Experiments 3 and 4 extended the results to thematic conditionals and showed that the pragmatic utility associated with believing a statement also affected the degree of belief in conditionals but not in logically equivalent quantified statements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Viscosity Measurements on Gaseous Argon, Krypton, and Propane1

A new vibrating-wire viscometer was designed to perform quasi-absolute measurements of very high precision on gases. It was applied to determine the viscosity of argon at temperatures of 298.15, 348.15, and 423.15 K and pressures up to 20 MPa, and the viscosity of krypton at 298.15 and 348.15 ,K and pressures up to 16 MPa. Furthermore, several isothermal series of viscosity measurements on gaseous propane were carried out. The subcritical isotherms at 298.15, 323.15, 348.15, and 366.15 K were restricted to 95% of the saturated vapor pressure, the supercritical isotherms at 373.15, 398.15, and 423.15 K to 20 MPa. In general, the measurements are characterized by a reproducibility of ±0.05% and an accuracy of ±0.2%. However, close to the critical point an accuracy of ±3% has to be accepted, mainly due to the uncertainty of the density. In this context the influence of the equation of state used for propane is discussed.     

Vergleichende Analyse der thermischen Beanspruchungs intensitäten bei normativen Raumbrandversuchen

International existieren verschiedene genormte Raumbrandprüfungen, in welchen das Brandverhalten von Wand‐ und Deckenprodukten unter realitätsnahen Einbaubedingungen untersucht wird. Die Prüfmethoden unterscheiden sich zum Teil erheblich hinsichtlich der Raumgeometrie, der Ventilationsöffnungen bzw. ‐verhältnisse sowie der Art und Leistung der verwendeten Zündquellen. Auf der Basis von Brandsimulationsrechnungen mit dem CFD‐Code FDS wurde die Intensität der resultierenden thermischen Produktbeanspruchung für ausgewählte Prüfräume vergleichend analysiert. Die Simulationsergebnisse zeigen, dass zwischen den betrachteten Methoden deutliche Unterschiede bestehen, die zu inkonsistenten Produktbeurteilungen führen können. Comparative analysis of thermal exposure conditions in standard room fire tests. Various standards exist worldwide that describe room fire tests for determining the reaction to fire behaviour of wall and ceiling products under end‐use conditions. The test methods differ with respect to the room geometry, the ventilation conditions and the type and heat output of the ignition source. Numerical simulations were performed using the CFD code FDS to comparatively analyse the resulting thermal exposure conditions for selected test rooms. The simulation results exhibit considerable differences between the analysed test methods, which may lead to inconsistent product assessments.     

Status,causes and controls of cyanobacterial blooms in Lake Erie

The Laurentian Great Lakes are among the most prominent sources of fresh water in the world. Lake Erie's infamous cyanobacterial blooms have, however, threatened the health of this valuable freshwater resource for decades. Toxic blooms dominated by the cyanobacterium Microcystis aeruginosa have most recently been one of primary ecological concerns for the lake. These toxic blooms impact the availability of potable water, as well as public health and revenues from the tourism and fishery industries. The socioeconomic effects of these blooms have spurred research efforts to pinpoint factors that drive bloom events. Despite decades of research and mitigation efforts, these blooms have expanded both in size and duration in recent years. However, through continued joint efforts between the Canadian and United States governments, scientists, and environmental managers, identification of the factors that drive bloom events is within reach. This review provides a summary of historical and contemporary research efforts in the realm of Lake Erie's harmful cyanobacterial blooms, both in terms of experimental and management achievements and insufficiencies, as well as future directions on the horizon for the lake's research community.     

Italian ryegrass silage in winter feeding of organic dairy cows: forage intake, milk yield and composition

BACKGROUND: Organic milk production aims at efficient use of home‐grown feeds, especially forages, to minimise the quantity of purchased feeds. In conventional agriculture, Italian ryegrass (Lolium multiflorum Lam.) is known for its high energy content and palatability, and the aim of the present study was to examine its suitability as feed for organic dairy cows. Therefore a feeding trial was conducted comparing a diet including 50% (of silage dry matter (DM)) of Italian ryegrass silage with a control diet based on grass/clover silage (a mixture of the second cut from permanent grassland and the second cut from a perennial clovergrass ley) alone. RESULTS: Inclusion of Italian ryegrass silage in the diet increased forage intake significantly (14.5 vs 13.4 kg DM in the control group) and concentrate intake did not differ, but milk yield was slightly lower (20.3 vs 21.0 kg) owing to the low energy and protein concentration of Italian ryegrass silage. CONCLUSION: Italian ryegrass was indeed found to be highly palatable, confirming in principle its suitability as feed for organic dairy cows. However, higher energy and protein concentrations in this forage would be necessary to translate the high intakes of Italian ryegrass silage into improved milk production as well. Copyright © 2010 Society of Chemical Industry     

Water sorption in poly(vinyl alcohol) membranes: An experimental and numerical study of solvent diffusion in a crosslinked polymer

The development of reliable mathematical models for mass transport in crosslinked polymers and their thorough experimental validation are of substantial interest in the design of technical membrane processes or the assessment of polymer performance when applications such as functional films and protective coatings are concerned.The present study aims at the joint experimental and numerical characterisation of mass transport during water vapour sorption into physically crosslinked poly(vinyl alcohol) membranes. A mathematical model comprising both phase equilibrium and the respective mass transport mechanisms is proposed and verified by means of in situ sorption kinetic measurements. Drawing on the independent determination of equilibrium solvent uptake, the comparison of model calculations and experimental sorption data demonstrates that water transport in the crosslinked polymer membrane is successfully described by pure Fickian diffusion with a simple exponential expression for the solvent diffusion coefficient to account for its pronounced concentration dependency, allowing the latter to be specified quantitatively.     

Role of the Blood-Brain Barrier in the Formation of Brain Metastases

The majority of brain metastases originate from lung cancer, breast cancer and malignant melanoma. In order to reach the brain, parenchyma metastatic cells have to transmigrate through the endothelial cell layer of brain capillaries, which forms the morphological basis of the blood-brain barrier (BBB). The BBB has a dual role in brain metastasis formation: it forms a tight barrier protecting the central nervous system from entering cancer cells, but it is also actively involved in protecting metastatic cells during extravasation and proliferation in the brain. The mechanisms of interaction of cancer cells and cerebral endothelial cells are largely uncharacterized. Here, we provide a comprehensive review on our current knowledge about the role of junctional and adhesion molecules, soluble factors, proteolytic enzymes and signaling pathways mediating the attachment of tumor cells to brain endothelial cells and the transendothelial migration of metastatic cells. Since brain metastases represent a great therapeutic challenge, it is indispensable to understand the mechanisms of the interaction of tumor cells with the BBB in order to find targets of prevention of brain metastasis formation.