Stokes flow due to infinite arrays of stokeslets in three dimensions

Infinite periodic arrays of stokeslets in three dimensions are summed up by obtaining various rapidly converging infinite series. The three cases treated here are: 1. Identical stokeslets distributed at constant intervals on a line parallel to a plate, 2. An array of identical stokeslets distributed on a two-dimensional periodic lattice on a plane parallel to a plate, 3. The same array, but parallel to and in between two plates. Computational results are shown and comparisons with previously averaged expressions are made.     

Conductive Scaffolds for Cardiac and Neuronal Tissue Engineering: Governing Factors and Mechanisms

Tissue engineering is a promising therapeutic approach in medicine, targeting the replacement of a diseased tissue with a healthy one grown within an artificial scaffold. Due to the high prevalence of cardiac and brain‐related ailments that involve some necrosis of tissue, cardiac and neuronal tissue engineering are intensely studied fields in regenerative medicine. A growing trend in the use of conductive scaffolds for the growth of these tissues has been witnessed recently. While the results are irrefutable, the mechanism of how an electrically conducting scaffold interacts with an electroactive tissue remains has remained elusive. An up‐to‐date summary of all work done in the field is reported, with a special focus on the specific contribution of the conductive scaffold on the performance of the formed tissue. The cell–scaffold electronic interface is then explored from an electrical engineering perspective. The electronic configuration of the system and the mechanisms and governing factors controlling the ability of a conductive scaffold to support cardiac and neuronal tissues are discussed. Using several simulations, the required conductivity of the scaffold in order for it to be suitable for tissue engineering—which also depends on the nature of the charge carriers—is also discussed.     

Cell-specific integration of artificial organelles based on functionalized polymer vesicles

Cell organelles are subcellular structures characterized by specific functionalities. They often consist of membrane-delineated microcompartments with a unique set of enzymes. Here we report the design of synthetic organelles based on nanometer-sized polymer vesicles, show their introduction into cells in a target-specific fashion, document their intact biochemical functionality in the cellular environment, and study their intracellular trafficking. This novel paradigm of introducing polymer-based artificial organelles to specific target cells for expansion of their biochemical capabilities appears suited for biomedical applications such as enzyme replacement in genetic diseases or, more generically, to add a desired biochemical function to a cell.     

Electron Hopping Across Hemin‐Doped Serum Albumin Mats on Centimeter‐Length Scales

Exploring long‐range electron transport across protein assemblies is a central interest in both the fundamental research of biological processes and the emerging field of bioelectronics. This work examines the use of serum‐albumin‐based freestanding mats as macroscopic electron mediators in bioelectronic devices. In particular, this study focuses on how doping the protein mat with hemin improves charge‐transport. It is demonstrated that doping can increase conductivity 40‐fold via electron hopping between adjacent hemin molecules, resulting in the highest measured conductance for a protein‐based material yet reported, and transport over centimeter length scales. The use of distance‐dependent AC impedance and DC current–voltage measurements allows the contribution from electron hopping between adjacent hemin molecules to be isolated. Because the hemin‐doped serum albumin mats have both biocompatibility and fabrication simplicity, they should be applicable to a range of bioelectronic devices of varying sizes, configurations, and applications.     

Levels of consumers’ agency and capacity as predictors for electricity demand reduction in the residential sector

A field study of 50 households in a collective community in Israel provides initial support for the hypotheses about the relations between actors’ agency, capacity and electricity demand reduction. ‘Agency’ refers to actors’ willingness and ability to make their own free choices and ‘capacity’ refers to actors’ ability to perform the choices they made. According to the hypotheses, change is more likely to happen when actors’ levels of agency and capacity are high; unlikely to happen when the levels are low and uncertain when there is a mismatch between levels of agency and capacity (one is high and the other low). In the research, levels of agency and capacity regarding 11 energy saving actions were self-reported and electricity consumption was metered before and during energy saving campaign. Findings show that levels of agency were lower than those of capacity for no-cost actions which require high engagement, while levels of capacity were lower than those of agency for high-cost action which require low engagement. In addition, households with high agency and high capacity reduced their electricity consumption by 9.39 % (on average); those with low agency and low capacity increased their consumption by 6.67 %; and those with a mismatch between agency and capacity reduced their consumption by 1.91 %.     

Capital deepening and regional inequality: an empirical analysis

We present a simple reproducible methodology for constructing regional capital stock data, which we apply to Israel. We find that capital deepening has been sigma-convergent since 1985. This process is “inverted” since capital stocks and capital–labor ratios in the richer center have been catching-up with their counterparts in the poorer periphery. We explain this phenomenon in terms of fundamental changes in regional policy. Despite this, regional wages have not been sigma-convergent because other wage determinants have been sigma-divergent.     

A case for automated large-scale semantic annotation

This paper describes Seeker, a platform for large-scale text analytics, and SemTag, an application written on the platform to perform automated semantic tagging of large corpora. We apply SemTag to a collection of approximately 264 million web pages, and generate approximately 434 million automatically disambiguated semantic tags, published to the web as a label bureau providing metadata regarding the 434 million annotations. To our knowledge, this is the largest scale semantic tagging effort to date.We describe the Seeker platform, discuss the architecture of the SemTag application, describe a new disambiguation algorithm specialized to support ontological disambiguation of large-scale data, evaluate the algorithm, and present our final results with information about acquiring and making use of the semantic tags. We argue that automated large-scale semantic tagging of ambiguous content can bootstrap and accelerate the creation of the semantic web.     

Do reef fish, variola louti and scarus niger, perform amodal completion? Evidence from a field study.

In terms of visual perception, coral reefs are structurally complex habitats. Therefore, visual stimuli that invoke territorial behavior in fish, causing them to respond to potential intruders and competitors, may be fragmented. Amodal completion was recently shown in a fish species. Here, we presented a mirror covered by occluders, with different squared openings arranged in a vertical or a horizontal broken line or a checkerboard formation, within their natural territories in the reef. Single small openings in the occluders did not trigger an attack on the reflected image, while specific configurations of them did so, suggesting that fish recognized an intruder in the fragmented image. The results suggest the use of amodal completion by fish although other possibilities cannot be rejected. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Toward intelligent nanosize bioreactors: a pH-switchable, channel-equipped, functional polymer nanocontainer

To develop an intelligent sensor-effector functionality on the nanoscale, a pH-switchable, controlled nanoreactor based on amphiphilic copolymer membranes was built. The nanovesicles were equipped with bacterial transmembrane ompF pore proteins and the pH-sensitive enzyme acid phosphatase, resulting in a switchable substrate processing at pH 4-6.5. Ideal pH and substrate concentrations for the reaction were determined experimentally. In future, the reactor might be used for self-regulating targeted diagnostic and therapeutic applications in medicine.