Patterned Surface Activation of Cyclo-Olefin Polymers for Biochip Applications

Two different surface activation methods (UV/ozone and oxygen plasma treatment) were applied for patterned surface activation of cyclo-olefin polymer (COP) surfaces combined with different masking techniques (metal shadow mask and protective tape). Surface properties were characterized by various methods such as contact angle measurement, ATR-IR, XPS and Surface enhanced ellipsometric contrast (SEEC) microscopy. UV/ozone and oxygen plasma allowed for patterned surface modification of COP leading to the formation of carboxylic and hydroxyl groups on the activated part of the surface. Stability against organic solvents was determined by rinsing the activated substrates with 2-propanol. For UV/ozone treatment it was found that a thin film of degradation products remains on the COP surface and is at least partly removed in the following washing or rinsing steps

Comment on "Liquid-Liquid Phase Transition in Supercooled Yttria-Alumina"

A Comment on the Letter by Adrian C. Barnes et al., Phys. Rev. Lett. 103 225702 (2009). The authors of the Letter offer a Reply

An ultraviolet simulator for the incident Martian surface radiation and its applications

Ultraviolet (UV) radiation can act on putative organic/biological matter at the Martian surface in several ways. Only absorbed, but not transmitted or reflected, radiation energy can be photo-chemically effective. The most important biological UV effects are due to photochemical reactions in nucleic acids, DNA or RNA, which constitute the genetic material of all cellular organisms and viruses. Protein or lipid effects generally play a minor role, but they are also relevant in some cases. UV radiation can induce wavelengths-specific types of DNA damage. At the same time it can also induce the photo-reversion reaction of a UV induced DNA photoproduct of nucleic acid bases, the pyrimidine dimers. Intense UVB and UVC radiation, experienced on early Earth and present-day Mars, has been revealed to be harmful to all organisms, including extremophile bacteria and spores. Moreover, the formation of oxidants, catalytically produced in the Martian environment through UV irradiation, may be responsible for the destruction of organic matter on Mars. Following this, more laboratory simulations are vital in order to investigate and understand UV effects on organic matter in the case of Mars. We have designed a radiation apparatus that simulates the anticipated Martian UV surface spectrum between 200 and 400 nm (UVC-UVA). The system comprises a UV enhanced xenon arc lamp, special filter-sets and mirrors to simulate the effects of the Martian atmospheric column and dust loading. We describe the technical setup and performance of the system and discuss its uses for different applications. The design is focused on portability, therefore, the Mars-UV simulator represents a device for several different Mars simulation facilities with specific emphasis on Mars research topics

Penetrometry of granular and moist planetary surface materials: Application to the Huygens landing site on Titan

The Huygens probe landed on the then unknown surface of Titan in January 2005. A small, protruding penetrometer, part of the Surface Science Package (SSP), was pushed into the surface material measuring the mechanical resistance of the ground as the probe impacted the landing site. We present laboratory penetrometry into room temperature surface analogue materials using a replica penetrometer to investigate further the nature of Titan's surface and examine the sensor's capabilities. The results are then compared to the flight instrument's signature and suggest the Titan surface substrate material consists of sand-sized particles with a mean grain size ~2 mm. A possible thin 7 mm coating with mechanical properties similar to terrestrial snow may overlie this substrate, although due to the limited data we are unable to detect any further layering or grading within the near-surface material. The unusual weakening with depth of the signature returned from Titan has, to date, only been reproduced using a damp sand target that becomes progressively wetter with depth, and supports the suggestion that the surface may consist of a damp and cohesive material with interstitial liquid contained between its grains. Comparison with terrestrial analogues highlights the unusual nature of the landing site material

Detection of first-order liquid/liquid phase transitions in yttrium oxide-aluminium oxide melts

We combine small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS) with aerodynamic levitation techniques to study in situ phase transitions in the liquid state under contactless conditions. At very high temperatures, yttria-alumina melts show a first-order transition, previously inferred from phase separation in quenched glasses. We show how the transition coincides with a narrow and reversible maximum in SAXS indicative of liquid unmixing on the nanoscale, combined with an abrupt realignment in WAXS features related to reversible shifts in polyhedral packing on the atomic scale. We also observed a rotary action in the suspended supercooled drop driven by repetitive transitions (a polyamorphic rotor) from which the reversible changes in molar volume (1.2 ± 0.2 cubic centimeters) and entropy (19 ± 4 joules mole–1 kelvin–1) can be estimated

Differences in Brain Function and Changes with Intervention in Children with Poor Spelling and Reading Abilities

Previous fMRI studies in English-speaking samples suggested that specific interventions may alter brain function in language-relevant networks in children with reading and spelling difficulties, but this research strongly focused on reading impaired individuals. Only few studies so far investigated characteristics of brain activation associated with poor spelling ability and whether a specific spelling intervention may also be associated with distinct changes in brain activity patterns. We here investigated such effects of a morpheme-based spelling intervention on brain function in 20 children with comparatively poor spelling and reading abilities using repeated fMRI. Relative to 10 matched controls, children with comparatively poor spelling and reading abilities showed increased activation in frontal medial and right hemispheric regions and decreased activation in left occipito-temporal regions prior to the intervention, during processing of a lexical decision task. After five weeks of intervention, spelling and reading comprehension significantly improved in the training group, along with increased activation in the left temporal, parahippocampal and hippocampal regions. Conversely, the waiting group showed increases in right posterior regions. Our findings could indicate an increased left temporal activation associated with the recollection of the new learnt morpheme-based strategy related to successful training

Efficient Passive ICS Device Discovery and Identification by MAC Address Correlation

Owing to a growing number of attacks, the assessment of Industrial Control Systems (ICSs) has gained in importance. An integral part of an assessment is the creation of a detailed inventory of all connected devices, enabling vulnerability evaluations. For this purpose, scans of networks are crucial. Active scanning, which generates irregular traffic, is a method to get an overview of connected and active devices. Since such additional traffic may lead to an unexpected behavior of devices, active scanning methods should be avoided in critical infrastructure networks. In such cases, passive network monitoring offers an alternative, which is often used in conjunction with complex deep-packet inspection techniques. There are very few publications on lightweight passive scanning methodologies for industrial networks. In this paper, we propose a lightweight passive network monitoring technique using an efficient Media Access Control (MAC) address-based identification of industrial devices. Based on an incomplete set of known MAC address to device associations, the presented method can guess correct device and vendor information. Proving the feasibility of the method, an implementation is also introduced and evaluated regarding its efficiency. The feasibility of predicting a specific device/vendor combination is demonstrated by having similar devices in the database. In our ICS testbed, we reached a host discovery rate of 100% at an identification rate of more than 66%, outperforming the results of existing tools.Comment: http://dx.doi.org/10.14236/ewic/ICS2018.

Challenges of Misbehavior Detection in Industrial Wireless Networks

In recent years, wireless technologies are increasingly adopted in many application domains that were either unconnected before or exclusively used cable networks. This paradigm shift towards - often ad-hoc - wireless communication has led to significant benefits in terms of flexibility and mobility. Alongside with these benefits, however, arise new attack vectors, which cannot be mitigated by traditional security measures. Hence, mechanisms that are orthogonal to cryptographic security techniques are necessary in order to detect adversaries. In traditional networks, such mechanisms are subsumed under the term "intrusion detection system" and many proposals have been implemented for different application domains. More recently, the term "misbehavior detection" has been coined to encompass detection mechanisms especially for attacks in wireless networks. In this paper, we use industrial wireless networks as an exemplary application domain to discuss new directions and future challenges in detecting insider attacks. To that end, we review existing work on intrusion detection in mobile ad-hoc networks. We focus on physical-layer-based detection mechanisms as these are a particularly interesting research direction that had not been reasonable before widespread use of wireless technology.Peer Reviewe

Anticoagulant activity of cellulose nanocrystals from isora plant fibers assembled on cellulose and sio2 substrates via a layer-by-layer approach

In this study, we report the isolation of cellulose nanocrystals (CNCs) from Isora plant fibers by sulfuric acid hydrolysis and their assembly on hydrophilic cellulose and silicon-di-oxide (SiO2) surfaces via a layer-by-layer (LBL) deposition method. The isolated CNCs were monodis-persed and exhibited a length of 200-300 nm and a diameter of 10-20 nm, a negative zetapotential (34-39 mV) over a wide pH range, and high stability in water at various concentrations. The multi-layered structure, adsorbed mass, conformational changes, and anticoagulant activity of sequen-tially deposited anionic (sulfated) CNCs and cationic polyethyleneimine (PEI) on the surfaces of cellulose and SiO2 by LBL deposition were investigated using a quartz crystal microbalance tech-nique. The organization and surface features (i.e., morphology, thickness, wettability) of CNCs ad-sorbed on the surfaces of PEI deposited at different ionic strengths (50-300 mM) of sodium chloride were analysed in detail by profilometry layer-thickness, atomic force microscopy and contact angle measurements. Compared to cellulose (control sample), the total coagulation time and plasma deposition were increased and decreased, respectively, for multilayers of PEI/CNCs. This study should provide new possibilities to fabricate and tailor the physicochemical properties of multilayer films from polysaccharide-based nanocrystals for various biomedical applications.Acknowledgments: The authors acknowledge Volker Ribitsch (retired) from the University of Graz/Austria for his support and valuable discussion for this manuscript. The authors also acknowledge the financial support from the Slovenian National Research Agency ARRS (Grant No. J4-1764).Scopu