Hypoxia and flow perfusion modulate proliferation and gene expression of articular chondrocytes on porous scaffolds

The combination of reduced oxygen tension and flow perfusion bioreactor culture is investigated for its effect on the proliferation, glycosaminoglycan production, and chondrogenic gene expression of bovine articular chondrocytes on porous polymer scaffolds. It was hypothesized that the combination of such factors would more closely replicate the in situ environment of these cells, leading to improvements in the cell phenotype. Chondrocytes were seeded onto electrospun poly(ε‐caprolactone) scaffolds and cultured in static or perfusion culture in either normoxic or hypoxic conditions for 6days. Results demonstrated that the combination of hypoxic and perfusion culture led to an increase in chondrocyte proliferation and glycosaminoglycan production, as well as an improvement in the ratio of collagen II/I gene expression over perfusion culture alone. The results demonstrate the need to combine multiple signals in vitro, in order to improve tissue growth by more closely replicating the native environment of cells. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3158–3166, 2013     

Modeling of the mechanical behavior of semisolid metallic alloys at high volume fractions of solid

A two-phase strain rate and pressure-dependent model that describes the mechanical behavior of semisolid materials at high volume fractions of solid as an interpolation between the limits of fully cohesive and fully cohesionless materials is presented. An internal variable that describes the degree of cohesion in the material is introduced. The proposed model predicts a reduction of the stress required to sustain undrained constant strain rate deformation. From numerical simulations it is shown that high strain rates result in near-undrained conditions and minimal phase segregation. This effect has important consequences in semisolid processing operations.     

Boundary Labeling with Octilinear Leaders

An illustration with textual labels may be hard to read if the labels overlap parts of the illustration. Boundary labeling addresses this problem by attaching the labels to the boundary of a rectangle that contains all features. Then, each feature should be connected to its associated label through a polygonal line, called leader, such that no two leaders intersect.     

Installation of PV systems in Greece—Reliability improvement in the transmission and distribution system

Photovoltaic (PV) power systems are becoming one of the most developing investment areas in the field of Renewable Energy Sources (RES). A statement of the status quo of PV power systems in Greece, and their contribution towards the improvement of power system reliability, is the scope of the present paper. Siting and installation of PV power systems is performed according to a recent Greek law, along with environmental and geographical constraints. Meteorological data are computed, formulated and imported to appropriate software in order to simulate the PV units and generate their power output. Data for unserved loads, resulting from load shedding during peak hours, are compared to the above estimated power production. Assuming that a proportion of the eventually unsupplied power could be provided by the accessed power generation of the PV units, the reliability of both transmission and distribution system is improved. The impact on the transmission system is shown by an improvement of LOLP and LOEP indices, whereas peak shaving for the Interconnected Greek Transmission System (IGTS) is also illustrated. For the distribution system the impact is quantified using the distribution system reliability indices SAIDI, SAIFI, and CAIDI. Finally, the resulting improvement is also expressed in financial terms.     

Mechanical and fracture properties of cement-based bi-materials after thermal cycling

This study investigates the effect of thermal cycles on the fracture properties of the cement-based bi-materials. Sixty eight cubes were exposed to a varied number of 24-hour thermal cycles ranging from 0 to 90 and subsequently were tested in a wedge splitting configuration. The mechanical and fracture properties of normal strength and high strength concretes are substantially improved after 30 thermal cycles, but less so after 90 thermal cycles both in isolation and when bonded to an ultra high-performance fibre-reinforced cement-based composite.     

Bandwidth-constrained queries in sensor networks

Sensor networks consist of battery-powered wireless devices that are required to operate unattended for long periods of time. Thus, reducing energy drain is of utmost importance when designing algorithms and applications for such networks. Aggregate queries are often used by monitoring applications to assess the status of the network and detect abnormal behavior. Since radio transmission often constitutes the biggest factor of energy drain in a node, in this paper we propose novel algorithms for the evaluation of bandwidth- constrained queries over sensor networks. The goal of our techniques is, given a target bandwidth utilization factor, to program the sensor nodes in a way that seeks to maximize the accuracy of the produced query results at the monitoring node, while always providing strong error guarantees to the monitoring application. This is a distinct difference of our framework from previous techniques that only provide probabilistic guarantees on the accuracy of the query result. Our algorithms are equally applicable when the nodes have ample power resources, but bandwidth consumption needs to be minimized, for instance in densely distributed networks, to ensure proper operation of the nodes. Our experiments with real sensor data show that bandwidth-constrained queries can substantially reduce the number of messages in the network while providing very tight error bounds on the query result.     

Listeria Meningitis Complicating Alemtuzumab Treatment in Multiple Sclerosis—Report of Two Cases

Alemtuzumab, a humanized monoclonal antibody targeting the surface molecule CD52, leads to a rapid depletion of immune cells in the innate and adaptive immune system. In phase 2 and 3 trials in multiple sclerosis (MS), infections have been reported more frequently in alemtuzumab than in interferon beta treated patients. Here we report two patients treated with alemtuzumab for MS developing Listeria meningitis few days after the first infusion cycle. Both patients recovered completely after prompt diagnosis and adequate treatment. Physicians and patients should be aware of this serious, but treatable complication.     

An Updated Review of Meat Authenticity Methods and Applications

Adulteration of foods is a serious economic problem concerning most foodstuffs, and in particular meat products. Since high-priced meat demand premium prices, producers of meat-based products might be tempted to blend these products with lower cost meat. Moreover, the labeled meat contents may not be met. Both types of adulteration are difficult to detect and lead to deterioration of product quality. For the consumer, it is of outmost importance to guarantee both authenticity and compliance with product labeling. The purpose of this article is to review the state of the art of meat authenticity with analytical and immunochemical methods with the focus on the issue of geographic origin and sensory characteristics. This review is also intended to provide an overview of the various currently applied statistical analyses (multivariate analysis (MAV), such as principal component analysis, discriminant analysis, cluster analysis, etc.) and their effectiveness for meat authenticity.