554 research outputs found
A new measure of resilience: An application to the London Underground
The many varied views on resilience indicate that it is an important concept which has significance in many disciplines, from ecology to psychology to risk/disaster management. Therefore, it is important to be able to quantifiably measure the resilience of systems, and thus be able to make decisions on how the resilience of the system can be improved. In this paper we will work with the definition, due to Pimm (1991), that resilience is "how fast a variable that has been displaced from equilibrium returns to it." We will think of a system as being more or less resilient depending on the speed with which a system recovers from disruptive events or shocks. Here we consider systems which revert to an equilibrium state from shocks, and introduce a measure of resilience by providing a quantification of the rapidity of these systems' recovery from shocks.We use a mean-reverting stochastic model to study the diffusive effects of shocks and we apply this model to the case of the London Underground. As a shock diffuses through the network, the human-flow in the network recovers from the shock. The speed with which the passenger counts return to normal is an indicator of how quickly the line is able to recover from the shock and thereafter resume normal operations
PERSISTENCE OF IMMUNITY TO POLIOMYELITIS AMONG A SOUTHERN POPULATION THAT RECEIVED FOUR DOSES OF OPV 5 TO OVER 15 YEARS BEFORE
The immune status against polioviruses was investigated in a population of 545 students aged 11-20 years residing in the Neapolitan area, who had completed the vaccination cycle with four doses of OPV 5 to over 15 years before. Assuming as unprotected those individuals without detectable neutralizing antibodies at the dilution 1:2, nobody resulted without protection against all types of poliovirus; 0.7% lacked antibodies only against type 1, 0.6% only against type 3 and none against type 2. A very slight decreasing trend was observed for GMT values in function of the distance from the last dose of OPV for polio 1 and 2, but not for polio 3. As expected, GMT values for polio 2 resulted higher than those for polio 1 and both were higher than those for polio 3, when calculated by age groups as well as by distance groups. The last four Italian cases of autochthonous paralytic poliomyelitis, occurred in the period 1981/83, regarded unvaccinated children aged 6 months-2 years, residing in the same geographical area to which the study population belong. In the same area a delay of immunization practices was also ascertained in the recent past. Results of this study confirm that a priority for public health services is to devote their human and economic resources to reduce the vaccination delay more than administrate a further fifth dose of OPV at the age of twelve
Implementing the âBest Template Searchingâ tool into Adenosiland platform
Background: Adenosine receptors (ARs) belong to the G protein-coupled receptors (GCPRs) family. The recent release of X-ray structures of the human A2A AR (h A2A AR ) in complex with agonists and antagonists has increased the application of structure-based drug design approaches to this class of receptors. Among them, homology modeling represents the method of choice to gather structural information on the other receptor subtypes, namely A1, A2B, and A3 ARs. With the aim of helping users in the selection of either a template to build its own models or ARs homology models publicly available on our platform, we implemented our web-resource dedicated to ARs, Adenosiland, with the âBest Template Searchingâ facility. This tool is freely accessible at the following web address: http://mms.dsfarm.unipd.it/Adenosiland/ligand.php.
Findings: The template suggestions and homology models provided by the âBest Template Searchingâ tool are guided by the similarity of a query structure (putative or known ARs ligand) with all ligands co-crystallized with hA2A AR subtype. The tool computes several similarity indexes and sort the outcoming results according to the index selected by the user.
Conclusions: We have implemented our web-resource dedicated to ARs Adenosiland with the âBest Template Searchingâ facility, a tool to guide template and models selection for hARs modelling. The underlying idea of our new facility, that is the selection of a template (or models built upon a template) whose co-crystallized ligand shares the highest similarity with the query structure, can be easily extended to other GPCRs
Interaction of plant amine oxidases with diaminoethers
Polyamines are ubiquitous compounds, which are involved in crucial physiological events
including cell growth and differentiation. The catabolic oxidative degradation of polyamines is
catalyzed by quinoprotein copper-containing amine oxidases (CAOs) and flavoprotein
polyamine oxidases (PAOs). Various synthetic polyamine analogs and polyamine derivatives
have been reported, which represent important tools (substrates or inhibitors) in the study of
catalytic properties of the enzymes. In this work, two related compounds were studied in the
reactions with plant amine oxidases: 1,8-diamino-3,6-dioxaoctane (DADO) and 1,10-bis(2-
pyridinylmethyl)-4,7-dioxa-1,10-diazadecane (BPDD). Based on activity and stoichiometry
assays together with spectrophotometric measurements, DADO can be considered a good
substrate for grass pea, lentil and E. characias CAOs with Km values in the range 10-4 â 10-3 M.
Its oxidative degradation produces the corresponding aminoaldehyde 8-amino-3,6-dioxaoctanal,
which does not undergo spontaneous cyclization (as it is known for the oxidation products of
natural substrates putrescine, cadaverine and spermidine) or polymerization in the reaction
mixture. Conversely, oat PAO does not oxidize DADO and is only weakly inhibited by the
compound (Ki = 1.6 mM towards putrescine). BPDD was found to be a competitive inhibitor of
both CAOs and PAOs with Ki values of 10-4 M. DADO could be suggested as a potential affinity
ligand for CAOs
Macromolecular-scale resolution in biological fluorescence microscopy
We demonstrate far-field fluorescence microscopy with a focal-plane resolution of 15â20 nm in biological samples. The 10- to 12-fold multilateral increase in resolution below the diffraction barrier has been enabled by the elimination of molecular triplet state excitation as a major source of photobleaching of a number of dyes in stimulated emission depletion microscopy. Allowing for relaxation of the triplet state between subsequent excitationâdepletion cycles yields an up to 30-fold increase in total fluorescence signal as compared with reported stimulated emission depletion illumination schemes. Moreover, it enables the reduction of the effective focal spot area by up to â140-fold below that given by diffraction. Triplet-state relaxation can be realized either by reducing the repetition rate of pulsed lasers or by increasing the scanning speed such that the build-up of the triplet state is effectively prevented. This resolution in immunofluorescence imaging is evidenced by revealing nanoscale protein patterns on endosomes, the punctuated structures of intermediate filaments in neurons, and nuclear protein speckles in mammalian cells with conventional optics. The reported performance of diffraction-unlimited fluorescence microscopy opens up a pathway for addressing fundamental problems in the life sciences
Washingtonia filifera seed extracts inhibit the islet amyloid polypeptide fibrils formations and α-amylase and α-glucosidase activity
Washingtonia filifera seeds have revealed to possess antioxidant properties, butyrylcholinesterase and xanthine oxidase inhibition activities. The literature has indicated a relationship between Alzheimerâs disease (AD) and type-2 diabetes (T2D). Keeping this in mind, we have now evaluated the inhibitory properties of W. filifera seed extracts on α-amylase, α-glucosidase enzyme activity and the Islet Amyloid Polypeptide (IAPP) fibrils formation. Three extracts from seeds of W. filifera were evaluated for their enzyme inhibitory effect and IC50 values were calculated for all the extracts. The inhibition mode was investigated by Lineweaver-Burk plot analysis and the inhibition of IAPP aggregate formation was monitored. W. filifera methanol seed extract appears as the most potent inhibitor of α-amylase, α-glucosidase, and for the IAPP fibril formation. Current findings indicate new potential of this extract that could be used for the identification or development of novel potential agents for T2D and AD
Cardiac tamponade occurred after endoscopic submucosal dissection : conservative management of the esophagopericardial fistula
Key Clinical Message
We describe the case of an esophagopericardial fistula generated after endo-
scopic submucosal dissection in a patient affected by a superficial esophageal
squamous cell carcinoma immediately treated with percutaneous pericardial
drainage and placement of a partially covered self-expanding metal stent that
has been removed using the stent-in-stent technique after 35 days
Multidisciplinary study of biological parameters and fatigue evolution in quay crane operators
In intermodal terminals the handling of containers and the number of accidents still depends on a wide range of
human errors due
to fatigue despite the automation level reached nowadays. For this reason it is very important to increase knowledge about the
factors affecting the propensity of operators to make
errors, increasing the chance of accidents happening. The
aim of this work is
to propose a novel approach to assess fatigue and performance lev
els in quay crane operators as a function of physiological
parameters and of the many varying boundary conditions encountered in daily work. During their work, quay crane
operators
have to deal with variable environmental conditions, such as task
type, wind speed and direction, lighting conditions that redu
ce
visibility that can require an exacting level
of attention. In the trial eight operators have been examined in a session lastin
g four
hours. All actual conditions are reproduced through a fully imme
rsive quay crane simulator. The operator completes the assigned
task (the same for each one) and can see through four wide monito
rs a high quality virtual reality view of the simulation. Most
biological parameters are acquired using different devices including a Holter ECG monitor, electromyographic monitoring the
four trunk muscles most involved in the test, eye tracker and seat
-
body pressure interface for both
seat pan and backrest. Changes
in physiological parameters have been monitored during the trial and interesting correlations with performance levels and
boundary conditions ha
ve been f
ound for each operator, in accord
ance with their age and skills.
The present study can form the
basis for further investigations aimed at developing a cost effective, reliable and robust system for monitoring increasing fat
igue
and for predicting the critical conditions
that may result in an acciden
Multidisciplinary Study of Biological Parameters and Fatigue Evolution in Quay Crane Operators
AbstractIn intermodal terminals the handling of containers and the number of accidents still depends on a wide range of human errors due to fatigue despite the automation level reached nowadays. For this reason it is very important to increase knowledge about the factors affecting the propensity of operators to make errors, increasing the chance of accidents happening. The aim of this work is to propose a novel approach to assess fatigue and performance levels in quay crane operators as a function of physiological parameters and of the many varying boundary conditions encountered in daily work. During their work, quay crane operators have to deal with variable environmental conditions, such as task type, wind speed and direction, lighting conditions that reduce visibility that can require an exacting level of attention. In the trial eight operators have been examined in a session lasting four hours. All actual conditions are reproduced through a fully immersive quay crane simulator. The operator completes the assigned task (the same for each one) and can see through four wide monitors a high quality virtual reality view of the simulation. Most biological parameters are acquired using different devices including a Holter ECG monitor, electromyographic monitoring the four trunk muscles most involved in the test, eye tracker and seat-body pressure interface for both seat pan and backrest. Changes in physiological parameters have been monitored during the trial and interesting correlations with performance levels and boundary conditions have been found for each operator, in accordance with their age and skills. The present study can form the basis for further investigations aimed at developing a cost effective, reliable and robust system for monitoring increasing fatigue and for predicting the critical conditions that may result in an accident
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