7,053 research outputs found

    Designing a Compensated–Kidney Donation System

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    Osteochondral lesions of the talus (OLTs) are the third most common type of osteochondral lesion and can cause pain and instability of the ankle joint. Episurf Medical AB is a medical technology company that develops individualized implants for patients who are suffering from focal cartilage lesions. Episurf have recently started a project that aims to implement their implantation technique in the treatment of OLTs. This master thesis was a part of Episurf’s talus project and the main goal of the thesis was to find the optimal implantation angle of the Episurf implant when treating OLTs. The optimal implantation angle was defined as the angle that minimized the maximum equivalent (von Mises) strain acting on the implant shaft during the stance phase of a normal gait cycle. It is desirable to minimize the strain acting on the implant shaft, since a reduction of the strain can improve the longevity of the implant. To find the optimal implantation angle a finite element model of an ankle joint treated with the Episurf implant was developed. In the model an implant with a diameter of 12 millimeters was placed in the middle part of the medial side of the talar dome. An optimization algorithm was designed to find the implantation angle, which minimized the maximum equivalent strain acting on the implant shaft. The optimal implantation angle was found to be a sagittal angle of 12.5 degrees and a coronal angle of 0 degrees. Both the magnitude and the direction of the force applied to the ankle joint in the simulated stance phase seemed to influence the maximum equivalent strain acting on the implant shaft. A number of simplifications have been done in the simulation of this project, which might affect the accuracy of the results. Therefore it is recommended that further, more detailed, simulations based on this project are performed in order to improve the result accuracy.Fokala broskskador pĂ„ talusbenet Ă€r den tredje vanligaste typen av fokala broskskador och kan ge upphov till smĂ€rta och instabilitet av fotleden. Episurf Medical AB Ă€r ett medicintekniskt företag som utvecklar individanpassade implantat för patienter med fokala broskskador. Episurf har nyligen pĂ„börjat ett projekt dĂ€r deras teknik ska anvĂ€ndas i behandlingen av fokala broskskador pĂ„ talusbenet. Den hĂ€r masteruppsatsen var en del i Episurfs talusprojekt och dess huvudmĂ„l var att finna den optimala implantationsvinkeln av Episurfs implantat i behandlingen av fokala broskskador pĂ„ talusbenet. Den optimala implanteringsvinkeln definierades som den vinkel som minimerade den effektiva von Mises-töjningen som verkade pĂ„ implantatskaftet under stance-fasen i en normal gĂ„ngcykel. Det Ă€r efterstrĂ€vansvĂ€rt att minimera belastningen pĂ„ implantatskaftet eftersom en reducering av belastningen kan förbĂ€ttra implantatets livslĂ€ngd. En finita element-modell av en fotled behandlad med Episurfs implantat utvecklades för att för att finna den optimala implantationsvinkeln. I modellen placerades ett implantat med en diameter pĂ„ 12 millimeter pĂ„ mittendelen av talus mediala sida. En optimeringsalgoritm utformades för att finna implantationsvinkeln som minimerade den effektiva von Mises-töjningen pĂ„ implantatskaftet. Den funna optimala implantationsvinkeln bestod av en vinkel pĂ„ 12.5 grader i sagittalplan och en vinkel pĂ„ 0 grader i koronalplan. BĂ„de storleken och riktningen pĂ„ kraften som applicerats pĂ„ fotleden under den simulerade stance-fasen av gĂ„ngcykeln verkade pĂ„verka belastningen pĂ„ implantatskaftet. Ett antal förenklingar har gjorts i projektets simuleringar, vilket kan pĂ„verka noggrannheten i resultatet. DĂ€rför rekommenderas att ytterligare, mer detaljerade simuleringar baserade pĂ„ det hĂ€r projektet görs för att förbĂ€ttra resultatets noggrannhet

    Statically Checking Web API Requests in JavaScript

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    Many JavaScript applications perform HTTP requests to web APIs, relying on the request URL, HTTP method, and request data to be constructed correctly by string operations. Traditional compile-time error checking, such as calling a non-existent method in Java, are not available for checking whether such requests comply with the requirements of a web API. In this paper, we propose an approach to statically check web API requests in JavaScript. Our approach first extracts a request's URL string, HTTP method, and the corresponding request data using an inter-procedural string analysis, and then checks whether the request conforms to given web API specifications. We evaluated our approach by checking whether web API requests in JavaScript files mined from GitHub are consistent or inconsistent with publicly available API specifications. From the 6575 requests in scope, our approach determined whether the request's URL and HTTP method was consistent or inconsistent with web API specifications with a precision of 96.0%. Our approach also correctly determined whether extracted request data was consistent or inconsistent with the data requirements with a precision of 87.9% for payload data and 99.9% for query data. In a systematic analysis of the inconsistent cases, we found that many of them were due to errors in the client code. The here proposed checker can be integrated with code editors or with continuous integration tools to warn programmers about code containing potentially erroneous requests.Comment: International Conference on Software Engineering, 201

    The peptide motif of the single dominantly expressed class I molecule of the chicken MHC can explain the response to a molecular defined vaccine of infectious bursal disease virus (IBDV)

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    In contrast to typical mammals, the chicken MHC (the BF-BL region of the B locus) has strong genetic associations with resistance and susceptibility to infectious pathogens as well as responses to vaccines. We have shown that the chicken MHC encodes a single dominantly expressed class I molecule whose peptide-binding motifs can determine resistance to viral pathogens, such as Rous sarcoma virus and Marek’s disease virus. In this report, we examine the response to a molecular defined vaccine, fp-IBD1, which consists of a fowlpox virus vector carrying the VP2 gene of infectious bursal disease virus (IBDV) fused with ?-galactosidase. We vaccinated parental lines and two backcross families with fp-IBD1, challenged with the virulent IBDV strain F52/70, and measured damage to the bursa. We found that the MHC haplotype B15 from line 15I confers no protection, whereas B2 from line 61 and B12 from line C determine protection, although another locus from line 61 was also important. Using our peptide motifs, we found that many more peptides from VP2 were predicted to bind to the dominantly expressed class I molecule BF2*1201 than BF2*1501. Moreover, most of the peptides predicted to bind BF2*1201 did in fact bind, while none bound BF2*1501. Using peptide vaccination, we identified one B12 peptide that conferred protection to challenge, as assessed by bursal damage and viremia. Thus, we show the strong genetic association of the chicken MHC to a T cell vaccine can be explained by peptide presentation by the single dominantly expressed class I molecule

    Partial Information Decomposition as a Unified Approach to the Specification of Neural Goal Functions

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    In many neural systems anatomical motifs are present repeatedly, but despite their structural similarity they can serve very different tasks. A prime example for such a motif is the canonical microcircuit of six-layered neo-cortex, which is repeated across cortical areas, and is involved in a number of different tasks (e.g.sensory, cognitive, or motor tasks). This observation has spawned interest in finding a common underlying principle, a 'goal function', of information processing implemented in this structure. By definition such a goal function, if universal, cannot be cast in processing-domain specific language (e.g. 'edge filtering', 'working memory'). Thus, to formulate such a principle, we have to use a domain-independent framework. Information theory offers such a framework. However, while the classical framework of information theory focuses on the relation between one input and one output (Shannon's mutual information), we argue that neural information processing crucially depends on the combination of \textit{multiple} inputs to create the output of a processor. To account for this, we use a very recent extension of Shannon Information theory, called partial information decomposition (PID). PID allows to quantify the information that several inputs provide individually (unique information), redundantly (shared information) or only jointly (synergistic information) about the output. First, we review the framework of PID. Then we apply it to reevaluate and analyze several earlier proposals of information theoretic neural goal functions (predictive coding, infomax, coherent infomax, efficient coding). We find that PID allows to compare these goal functions in a common framework, and also provides a versatile approach to design new goal functions from first principles. Building on this, we design and analyze a novel goal function, called 'coding with synergy'. [...]Comment: 21 pages, 4 figures, appendi

    Public Policy and the Missing Link: A Progress Report on the Design and Implementation of the Massachusetts Linked Deposit Program

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    The idea underlying the Massachusetts Linked Deposit Program (LDP), which has been operated by the Treasurer since 1978, is that a portion of the money in the state\u27s General Fund is deposited in Massachusetts banks, with the amounts awarded to individual banks linked to their performance in serving the people and communities of Massachusetts. Bidding banks must offer a required minimum interest rate and must furnish specific information on the composition of their loan and investment portfolios. This information is used to compute a linked deposit score for each bank, which provides a basis for linking the awarding of public deposits to the performance of private banking institutions. Following the awards of May 1985, a total of $142.8 million in LDP funds was held by 79 banks. A previous report by the present author, Private Banks and Public Money: An Analysis of the Design and Implementation of the Massachusetts Linked Deposit Program [published by the McCormack Institute in early 1985] presented the initial results of the first systematic review and evaluation of the Massachusetts LDP that had been undertaken since the program\u27s inception. This report identified serious deficiencies in every program aspect reviewed. Its most important single finding was that there was in fact no linkage between the scores and awards — that is, that the size of the deposits awarded to individual banks was unrelated to the LDP scores calculated for those banks by the Treasurer. Private Banks and Public Money included a number of constructive proposals for strengthening and improving the Massachusetts LDP. In response, the Treasurer\u27s office implemented a number of significant changes in the forms and procedures used for the May 1985 cycle of bids and awards. The present report describes and evaluates the design and implementation of these modifications. The principal conclusion that emerges from the analysis presented in the body of this report is that although significant improvements were introduced in May 1985, the two major conclusions of our previous study remain valid: (1) there is [still] in fact no linkage in the Massachusetts linked deposit program as it is currently operated and (2) the Massachusetts LDP [still] falls far short of being \u27well-designed, well-implemented, and well-publicized\u27 — that is, it [still] fails to meet the three-part criterion originally set forth by the Special Commission on State Investment
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