Membranes for spontaneous separation of pedestrian counter flows

Designing efficient traffic lanes for pedestrians is a critical aspect of urban planning as walking remains the most common form of mobility among the increasingly diverse methods of transportation. Herein, we investigate pedestrian counter flows in a straight corridor, in which two groups of people are walking in opposite directions. We demonstrate, using a molecular dynamics approach applying the social force model, that a simple array of obstacles improves flow rates by producing flow separations even in crowded situations. We also report on a developed model describing the separation behavior that regards an array of obstacles as a membrane and induces spontaneous separation of pedestrians groups. When appropriately designed, those obstacles are fully capable of controlling the filtering direction so that pedestrians tend to keep moving to their left (or right) spontaneously. These results have the potential to provide useful guidelines for industrial designs aimed at improving ubiquitous human mobility.Comment: Manuscript accepted for publication in Europhysics Letter

Analysis of expressed sequence tags and identification of genes encoding cell-wall-degrading enzymes from the fungivorous nematode Aphelenchus avenae

<p>Abstract</p> <p>Background</p> <p>The fungivorus nematode, <it>Aphelenchus avenae </it>is widespread in soil and is found in association with decaying plant material. This nematode is also found in association with plants but its ability to cause plant disease remains largely undetermined. The taxonomic position and intermediate lifestyle of <it>A. avenae </it>make it an important model for studying the evolution of plant parasitism within the Nematoda. In addition, the exceptional capacity of this nematode to survive desiccation makes it an important system for study of anhydrobiosis. Expressed sequence tag (EST) analysis may therefore be useful in providing an initial insight into the poorly understood genetic background of <it>A. avenae</it>.</p> <p>Results</p> <p>We present the generation, analysis and annotation of over 5,000 ESTs from a mixed-stage <it>A. avenae </it>cDNA library. Clustering of 5,076 high-quality ESTs resulted in a set of 2,700 non-redundant sequences comprising 695 contigs and 2,005 singletons. Comparative analyses indicated that 1,567 (58.0%) of the cluster sequences had homologues in <it>Caenorhabditis elegans</it>, 1,750 (64.8%) in other nematodes, 1,321(48.9%) in organisms other than nematodes, and 862 (31.9%) had no significant match to any sequence in current protein or nucleotide databases. In addition, 1,100 (40.7%) of the sequences were functionally classified using Gene Ontology (GO) hierarchy. Similarity searches of the cluster sequences identified a set of genes with significant homology to genes encoding enzymes that degrade plant or fungal cell walls. The full length sequences of two genes encoding glycosyl hydrolase family 5 (GHF5) cellulases and two pectate lyase genes encoding polysaccharide lyase family 3 (PL3) proteins were identified and characterized.</p> <p>Conclusion</p> <p>We have described at least 2,214 putative genes from <it>A. avenae </it>and identified a set of genes encoding a range of cell-wall-degrading enzymes. This EST dataset represents a starting point for studies in a number of different fundamental and applied areas. The presence of genes encoding a battery of cell-wall-degrading enzymes in <it>A. avenae </it>and their similarities with genes from other plant parasitic nematodes suggest that this nematode can act not only as a fungal feeder but also a plant parasite. Further studies on genes encoding cell-wall-degrading enzymes in <it>A. avenae </it>will accelerate our understanding of the complex evolutionary histories of plant parasitism and the use of genes obtained by horizontal gene transfer from prokaryotes.</p

Sinus node dysfunction after repair of partial anomalous pulmonary venous connection

ObjectivesSinus node dysfunction is known as a major complication after repair of partial anomalous pulmonary venous connection. We retrospectively analyzed the results of the atrial wall flap technique compared with the results of patch repair or direct suturing in the intra-atrial tunnel technique.MethodsBetween 1991 and 2007, 23 patients (mean age, 6 years; range, 5 months–17 years) with partial anomalous pulmonary venous connection underwent surgical intervention. The right anomalous pulmonary veins drained to either the right atrium or superior vena cava in 8 and 15 patients, respectively. Patients were divided into 2 groups: group F (n = 14), who had repair with an atrial flap, and group N (n = 9), who had repair without an atrial flap. All patients had normal sinus rhythm preoperatively.ResultsNo patients had signs of superior vena cava or pulmonary venous obstruction within a mean follow-up of 4.8 years. One patient in group F required pacemaker implantation. In the early postoperative period, sinus node dysfunction developed in 93% of group F and 44% of group N patients (P < .01) and was prolonged until discharge in 57% of group F and 0% of group N patients (P < .01). At the most recent clinical visit, sinus node dysfunction was identified in 50% of group F patients, whereas all patients in group N had normal sinus rhythm (P < .02).ConclusionsThe atrial flap technique, which requires incision or suture crossing the crista terminalis, could cause sinus node dysfunction, whereas the intra-atrial rerouting method with a patch or direct suture maintains normal sinus node function postoperatively

Design and optimization of a wideband impact mode piezoelectric power generator

This paper proposes a new design of an impact mode piezoelectric power generator that is able to operate in a wide frequency bandwidth by using a round piezoelectric ceramic as the energy converter. The evaluation results show that the output of the power generator can be optimized by implementing a so-called indirect impact configuration. To realize this type of configuration, a shim plate is placed between the piezoelectric ceramic and the hitting structure. At a certain base excitation frequency, the output efficiency of this configuration increases to about 4.3 times that of the direct impact configuration. Furthermore, it is demonstrated that the designated power generator is able to generate electric energy up to approximately 1.57 mJ within 120 s from the vibration of a moving vehicle

Membrane-Type 1 Matrix Metalloproteinase Cleaves Cd44 and Promotes Cell Migration

Migratory cells including invasive tumor cells frequently express CD44, a major receptor for hyaluronan and membrane-type 1 matrix metalloproteinase (MT1-MMP) that degrades extracellular matrix at the pericellular region. In this study, we demonstrate that MT1-MMP acts as a processing enzyme for CD44H, releasing it into the medium as a soluble 70-kD fragment. Furthermore, this processing event stimulates cell motility; however, expression of either CD44H or MT1-MMP alone did not stimulate cell motility. Coexpression of MT1-MMP and mutant CD44H lacking the MT1-MMP–processing site did not result in shedding and did not promote cell migration, suggesting that the processing of CD44H by MT1-MMP is critical in the migratory stimulation. Moreover, expression of the mutant CD44H inhibited the cell migration promoted by CD44H and MT1-MMP in a dominant-negative manner. The pancreatic tumor cell line, MIA PaCa-2, was found to shed the 70-kD CD44H fragment in a MT1-MMP–dependent manner. Expression of the mutant CD44H in the cells as well as MMP inhibitor treatment effectively inhibited the migration, suggesting that MIA PaCa-2 cells indeed use the CD44H and MT1-MMP as migratory devices. These findings revealed a novel interaction of the two molecules that have each been implicated in tumor cell migration and invasion