The role of substrate morphology for the cytokine release profile of immature human primary macrophages

There is increasing evidence that the physicochemical nature of any given material is a dominant factor for the release of cytokines by innate immune cells, specifically of macrophages, and thus majorly influences their interaction with other cell types. Recently, we could show that the 3D structure of star shaped polytheylene oxide–polypropylene oxide co-polymers (sP(EO-stat-PO))-hydrogel coated substrates has a stronger influence on the release pattern of cytokines after 7 days of culture than surface chemistry. Here, we focused on the analysis of cytokine release over time and a more detailed analysis of cell morphology by scanning electron microscopy (SEM). Therefore, we compared different strategies for SEM sample preparation and found that using osmium tetroxide combined with aqua bidest led to best preparation results. For cytokine release we show significant changes from day 3 to day 7 of cell culture. After 3 days, the sP(EO-stat-PO)-coated substrates led to an induction of pro-angiogenic CCL3 and CCL4, and of low amounts of the anti-inflammatory IL10, which declined at day 7. In contrast, pleiotropic IL6 and the pro-inflammatory TNFα and IL1β were expressed stronger at day 7 than at day 3.     

Strain localization characteristics of loose saturated Toyoura sand in undrained cyclic torsional shear tests with initial static shear

Strain localization, or the formation of shear bands, is a key aspect in understanding soil failure mechanisms. While efforts have been made in terms of measuring the shear band properties and the stress–strain behavior within shear bands, there are still uncertainties regarding when shear bands initiate and their influence on the development of large ground deformation. In this paper, the limiting value of shear strain, at which strain localization appears during undrained cyclic torsional shear tests with initial static shear, performed on loose Toyoura sand specimens (Dr=44–48%) up to a single amplitude of shear strain exceeding 50%, was evaluated. Non-uniform specimen deformation was observed at strain levels larger than 20%. However, the onset of strain localization could not be defined on the basis of visual observations. Therefore, the limiting values for half of the double amplitude (γ_DA/2) and single amplitude (γ_SA) shear strain, to initiate strain localization, were determined from test results based on changes in the deviator stress response and strain accumulation properties as well as changes in the strain-softening behavior during cyclic shear. It was found that γ_SA is a more appropriate parameter than γ_DA/2. Irrespective of the static shear stress level, the limiting strain value for γ_SA was evaluated to be in the range of 23–28% for liquefied loose Toyoura sand specimens (i.e., stress reversal and intermediate tests). Alternatively, the limiting strain value could not be properly defined when liquefaction did not occur (i.e., non-reversal stress tests), although various methods were employed.     

Analysis of particle-to-particle elastic interactions in syntactic foams

This work analyzes the elastic interaction between a pair of hollow particles embedded in a dissimilar medium subjected to remote uniaxial tensile loading. The Boussinesq-Papkovich stress function approach is combined with a multi-pole series expansion to derive a semi-analytical solution of the Navier-Cauchy equation and determine stress and displacement fields in the inclusions and the surrounding medium. Stress profiles, stress intensification factors, circumferential stress resultants in the particles, and strain energy storage are presented for a broad range of particle wall thicknesses, sizes, and relative inter-particle distances. Results specialized to glass-vinyl ester systems demonstrate that particle wall thicknesses and size distributions can be used to modulate the effects of particle-to-particle interaction on the overall mechanical behavior of syntactic foams.     

Ensuring food safety by an innovative fermented sausage manufacturing system

Accelerated production of dry fermented sausages by shortening the drying-ripening process represents one of the new developments in meat product technology and is expected to have a promising future. However, food safety concerns, which could exist when processes are shortened, must be investigated in particular. In the present challenge test, the fate of Listeria monocytogenes and Salmonella was investigated in acid (pH 4.8) and low-acid (pH 5.3) chorizo that were fermented, thermally treated and dried either by the accelerated drying system QDS process^® or the traditional process. Even though the innovative QDS process^® substantially shortened the drying time when compared to the traditional drying system, results showed that in case of low level contamination of raw meat, the same product safety was achieved.     

Clone wars: Distributed detection of clone attacks in mobile WSNs

Among security challenges raised by mobile Wireless Sensor Networks, clone attack is particularly dreadful since it makes an adversary able to subvert the behavior of a network just leveraging a few replicas of some previously compromised sensors. In this work, we provide several contributions: first, we introduce two novel realistic adversary models, the vanishing and the persistent adversary, characterized by different compromising capability. We then propose two distributed, efficient, and cooperative protocols to detect replicas: History Information-exchange Protocol (HIP) and its optimized version (HOP). Both HIP and HOP leverage just local (one-hop) communications and node mobility, and differ for the amount of computation required. We study their behavior against the introduced types of attacker, considering two different mobility models and comparing our solutions against the state of the art. Both analysis and simulation results show that our solutions are effective and efficient, providing high detection rate, while incurring limited overhead.     

Opportunities in Opportunistic Computing

When two devices come into contact, albeit opportunistically, it provides a great opportunity to match services to resources, exchange information, cyberforage, execute tasks remotely, and forward messages.     

Obituary: Carolyn R. Payton (1925-2001).

Memorializes Carolyn R. Payton for being a pioneer both as an African American and as a woman, in her roles as researcher, teacher, administrator, individual and group therapist, and US Peace Corps director. She was honored for her pioneering contributions to multicultural psychology. Carolyn Payton exemplified a life of conscious purposefulness and determination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partially dynamic efficient algorithms for distributed shortest paths

We study the dynamic version of the distributed all-pairs shortest paths problem. Most of the solutions given in the literature for this problem, either (i) work under the assumption that before dealing with an edge operation, the algorithm for the previous operation has to be terminated, that is, they are not able to update shortest paths concurrently, or (ii) concurrently update shortest paths, but their convergence can be very slow (possibly infinite) due to the looping and counting infinity phenomena. In this paper, we propose partially dynamic algorithms that are able to concurrently update shortest paths. We experimentally analyze the effectiveness and efficiency of our algorithms by comparing them against several implementations of the well-known Bellman–Ford algorithm.     

The Acoustic Characterization of Broom Fibers

Natural materials are becoming a valid alternative to traditional synthetic ones for sound absorption applications. In this paper, the acoustic properties of broom fibers are reported and discussed. Broom plants grow up on hills and mountains and are common in many Mediterranean countries. The materials were cut and shredded to prepare several samples. Test specimens made of broom pieces with a diameter from 1.5 mm to 4 mm were prepared. The normal sound absorption for samples with a thickness of 60 mm, 80 mm and 120 mm was then measured. Results are particularly promising especially above 500 Hz, as the samples consistently reported a normal sound absorption above 0.5. The increase in the sample thickness allowed to obtain higher sound absorption at lower frequencies, as generally expected for porous materials. The main limit of the investigated samples was the appearance of sound absorption resonances. These were more evident for the samples composed of pieces with larger diameter, and may be attributed to the loose nature of the tested samples.