Expression of the beta 7 integrin by human endothelial cells

Integrin adhesion receptors mediate fundamental intercellular interactions of many cell types as well as cellular interactions with specific extracellular matrix molecules. To date, the beta 7 integrin has been shown to be expressed by leukocyte subsets and to mediate interactions of these cells with extracellular matrix molecules as well as with endothelial and epithelial cells. The data presented here indicate that human endothelial cells also express the beta 7 integrin both in vitro and in situ. Analysis of cDNA indicated that endothelial beta 7 was identical to that expressed by leukocytes. Cell surface expression of beta 7 was increased by exposure of the endothelium to the pro-inflammatory cytokines, tumor necrosis factor-alpha and interleukin-1 beta. In leukocytes, beta 7 complexes with alpha 4 or alpha E integrin chains. Endothelial cells also expressed a number of alpha-integrin chains, including alpha 4, but not alpha E. The expression and utilization of beta 7, presumably complexed with alpha 4, by endothelial cells may be instrumental in the maintenance of the function or phenotype of endothelial cells.     

Proton-Conductive Melanin-Like Fibers through Enzymatic Oxidation of a Self-Assembling Peptide

Melanin pigments have various properties that are of technological interest including photo- and radiation protection, rich coloration, and electronic functions. Nevertheless, laboratory-based synthesis of melanin and melanin-like materials with morphologies and chemical structures that are specifically optimized for these applications, is currently not possible. Here, melanin-like materials that are produced by enzymatic oxidation of a supramolecular tripeptide structures that are rich in tyrosine and have a 1D morphology are demonstrated, that are retained during the oxidation process while conducting tracks form through oxidative tyrosine crosslinking. Specifically, a minimalistic self-assembling peptide, Lys–Tyr–Tyr (KYY) with strong propensity to form supramolecular fibers, is utilized. Analysis by Raman spectroscopy shows that the tyrosines are pre-organized inside these fibers and, upon enzymatic oxidation, result in connected catechols. These form 1D conducting tracks along the length of the fiber, which gives rise to a level of internal disorder, but retention of the fiber morphology. This results in highly conductive structures demonstrated to be dominated by proton conduction. This work demonstrates the ability to control oxidation but retain a well-defined fibrous morphology that does not have a known equivalent in biology, and demonstrate exceptional conductivity that is enhanced by enzymatic oxidation.     

Tactful calling: investigating asymmetric social dilemmas in mobile communications

Recipients of phone calls face a constant dilemma between ignoring calls at the possible expense of offending the caller, missing business opportunities or neglecting family members on one hand; and answering them at the expense of interrupting their train of thought or appearing rude and impolite towards others with whom they share a social activity on the other hand. We studied people's attitudes regarding these dilemmas, with emphasis on their social aspects. In a cross-cultural study, conducted in Israel and in Germany, we surveyed both caller and recipient attitudes towards answering mobile phone calls in various circumstances. The study also assessed the aspects of providing contextual information about a call prior to it being answered, including types of information deemed most valuable. The results emphasise the importance of social norms in affecting respondents’ attitudes towards making or accepting phone calls regardless of role (caller or recipient), gender or culture. We also found that the norms in the physical context (e.g. being in a meeting) prevailed over norms in the virtual context (e.g. the phone call). Cultural and gender differences did not affect the degree to which people were frustrated by insufficient information regarding the other party's context. However, these factors did affect the suggested design solutions to this problem. The research provides insight into the social aspects of the problem of interruptive mobile phone calls and towards designing applications that help users maintain politeness while handling the caller–recipient dilemma.     

Grape clusters and foliage detection algorithms for autonomous selective vineyard sprayer

While much of modern agriculture is based on mass mechanized production, advances in sensing and manipulation technologies may facilitate precision autonomous operations that could improve crop yield and quality while saving energy, reducing manpower, and being environmentally friendly. In this paper, we focus on autonomous spraying in vineyards and present four machine vision algorithms that facilitate selective spraying. In the first set of algorithms we show how statistical measures, learning, and shape matching can be used to detect and localize the grape clusters to guide selected application of hormones to the fruit, but not the foliage. We also present another algorithm for the detection and localization of foliage in order to facilitate precision application of pesticide. All image-processing algorithms were tested on data from movies acquired in vineyards during the growing season of 2008 and their evaluation includes analyses of the potential pesticide and hormone reduction. Results show 90% accuracy of grape cluster detection leading to 30% reduction in the use of pesticides. The database of images is placed on the Internet and available to the public to continue developing the detection algorithms.     

A computationally efficient tracker with direct appearance-kinematic measure and adaptive Kalman filter

Visual tracking is considered a common procedure in many real-time applications. Such systems are required to track objects under changes in illumination, dynamic viewing angle, image noise and occlusions (to name a few). But to maintain real-time performance despite these challenging conditions, tracking methods should require extremely low computational resources, therefore facing a trade-off between robustness and speed. Emergence of new consumer-level cameras capable of capturing video in 60 fps challenges this tradeoff even further. Unfortunately, state-of-the-art tracking techniques struggle to meet frame rates over 30 VGA-resolution fps with standard desktop power, let alone on typically-weaker mobile devices. In this paper we suggest a significantly cheaper computational method for tracking in colour video clips, that greatly improves tracking performance, in terms of robustness/speed trade-off. The suggested approach employs a novel similarity measure that explicitly combines appearance with object kinematics and a new adaptive Kalman filter extends the basic tracking to provide robustness to occlusions and noise. The linear time complexity of this method is reflected in computational efficiency and high processing rate. Comparisons with two recent trackers show superior tracking robustness at more than 5 times faster operation, all using naïve C/C++ implementation and built-in OpenCV functions.     

Reducing the size of resolution proofs in linear time

DPLL-based SAT solvers progress by implicitly applying binary resolution. The resolution proofs that they generate are used, after the SAT solver’s run has terminated, for various purposes. Most notable uses in formal verification are: extracting an unsatisfiable core, extracting an interpolant, and detecting clauses that can be reused in an incremental satisfiability setting (the latter uses the proof only implicitly, during the run of the SAT solver). Making the resolution proof smaller can benefit all of these goals: it can lead to smaller cores, smaller interpolants, and smaller clauses that are propagated to the next SAT instance in an incremental setting. We suggest two methods that are linear in the size of the proof for doing so. Our first technique, called Recycle-Units uses each learned constant (unit clause) (x) for simplifying resolution steps in which x was the pivot, prior to when it was learned. Our second technique, called   simplifies proofs in which there are several nodes in the resolution graph, one of which dominates the others, that correspond to the same pivot. Our experiments with industrial instances show that these simplifications reduce the core by ≈5% and the proof by ≈13%. It reduces the core less than competing methods such as run- till- fix, but whereas our algorithms are linear in the size of the proof, the latter and other competing techniques are all exponential as they are based on SAT runs. If we consider the size of the proof (the resolution graph) as being polynomial in the number of variables (it is not necessarily the case in general), this gives our method an exponential time reduction comparing to existing tools for small core extraction. Our experiments show that this result is evident in practice more so for the second method: rarely it takes more than a few seconds, even when competing tools time out, and hence it can be used as a cheap proof post-processing procedure.     

The Mitochondrial Protein Translocation Motor: Structural Conservation between the Human and Yeast Tim14/Pam18-Tim16/Pam16 co-Chaperones

Most of our knowledge regarding the process of protein import into mitochondria has come from research employing Saccharomyces cerevisiae as a model system. Recently, several mammalian homologues of the mitochondrial motor proteins were identified. Of particular interest for us is the human Tim14/Pam18-Tim16/Pam16 complex. We chose a structural approach in order to examine the evolutionary conservation between yeast Tim14/Pam18-Tim16/Pam16 proteins and their human homologues. For this purpose, we examined the structural properties of the purified human proteins and their interaction with their yeast homologues, in vitro. Our results show that the soluble domains of the human Tim14/Pam18 and Tim16/Pam16 proteins interact with their yeast counterparts, forming heterodimeric complexes and that these complexes interact with yeast mtHsp70.     

Activated T cells acquire endothelial cell surface determinants during transendothelial migration

Activated T cells acquire endothelial cell (EC) plasma membrane constituents during transendothelial migration. This was assessed using an in vitro model system in which human peripheral blood CD4+ T cells migrated through confluent monolayers of HUVEC. Flow cytometry of migrated CD4+ T cells demonstrated that activated, but not resting, T cells acquired a variety of endothelial surface determinants, including CD31, CD49d, CD54, CD61, and CD62E. The extracellular domains of these molecules were detected on migrated T cells with mAbs, including those directed to the ligand-binding regions. A number of approaches were employed to document that the acquisition of these molecules was uniquely accomplished by activated T cells and clearly involved transfer from both resting and TNF-alpha-activated EC. Acquisition of endothelial markers by activated T cells occurred as part of the transfer of membrane components, as migrating T cells acquired EC membranes prelabeled with the lipophilic dye, 3,3'-dihexadecyloxacarbocyanine perchlorate (DiOC-16), along with EC surface proteins. Thus, during transendothelial migration, activated T cells acquire endothelial membrane components, and as a result may deliver them to perivascular sites.     

The classification of cyclooxygenase inhibitors

In summary, precise classification of COX inhibitors has important clinical implications for efficacy and toxicity. However, classification of these agents clinically is difficult because there are insufficient data to predict correlations between biochemical and pharmacologic properties and the clinical effect of a given agent. In any case, specific COX-2 inhibitors are expected to show antiinflammatory and analgesic activities equivalent to those of NSAID, as well as significant reductions in the incidence of the life threatening side effects (i.e., GI bleeding) associated with COX-1 inhibition. The advantages of preferential COX-2 inhibitors may be more subtle and therefore more difficult to verify in clinical trials.