63 research outputs found

    Link Mining for Kernel-based Compound-Protein Interaction Predictions Using a Chemogenomics Approach

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    Virtual screening (VS) is widely used during computational drug discovery to reduce costs. Chemogenomics-based virtual screening (CGBVS) can be used to predict new compound-protein interactions (CPIs) from known CPI network data using several methods, including machine learning and data mining. Although CGBVS facilitates highly efficient and accurate CPI prediction, it has poor performance for prediction of new compounds for which CPIs are unknown. The pairwise kernel method (PKM) is a state-of-the-art CGBVS method and shows high accuracy for prediction of new compounds. In this study, on the basis of link mining, we improved the PKM by combining link indicator kernel (LIK) and chemical similarity and evaluated the accuracy of these methods. The proposed method obtained an average area under the precision-recall curve (AUPR) value of 0.562, which was higher than that achieved by the conventional Gaussian interaction profile (GIP) method (0.425), and the calculation time was only increased by a few percent

    Acyclovir for treating varicella in otherwise healthy children and adolescents: a systematic review of randomised controlled trials

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    BACKGROUND: Acyclovir has the potential to shorten the course of chickenpox which may result in reduced costs and morbidity. We conducted a systematic review of randomised controlled trials that evaluated acyclovir for the treatment of chickenpox in otherwise healthy children. METHODS: MEDLINE, EMBASE, and the Cochrane Library were searched. The reference lists of relevant articles were examined and primary authors and Glaxo Wellcome were contacted to identify additional trials. Two reviewers independently screened studies for inclusion, assessed study quality using the Jadad scale and allocation concealment, and extracted data. Continuous data were converted to a weighted mean difference (WMD). Overall estimates were not calculated due to differences in the age groups studied. RESULTS: Three studies were included. Methodological quality was 3 (n = 2) and 4 (n = 1) on the Jadad scale. Acyclovir was associated with a significant reduction in the number of days with fever, from -1.0 (95% CI -1.5,-0.5) to -1.3 (95% CI -2.0,-0.6). Results were inconsistent with respect to the number of days to no new lesions, the maximum number of lesions and relief of pruritis. There were no clinically important differences between acyclovir and placebo with respect to complications or adverse effects. CONCLUSION: Acyclovir appears to be effective in reducing the number of days with fever among otherwise healthy children with chickenpox. The results were inconsistent with respect to the number of days to no new lesions, the maximum number of lesions and the relief of itchiness. The clinical importance of acyclovir treatment in otherwise healthy children remains controversial

    Energy-optimal current distribution in a complex linear electrical network with pulse or periodic voltage and current signals. Optimal control

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    The article presents that in the circuits of electrical signals belonging to the L1-impulses space or periodic signals space, real distribution of electrical currents occurs which does not meet the principle of minimum energy losses. The paper presents a solution of this problem by using the control system in the form of current-dependent voltage sources entering it into a meshes set of a complex RLC network. It has been shown that the control is energy-neutral

    Investigations, analysis and assessment of certain aspects of thermo-mechanical and chemical resistance of graphite nozzles to action of combustion products of sustaining solid rocket propellant charges applied in propulsion systems of GROM missiles

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    W artykule przedstawiono pewne aspekty badania, analizy i oceny odporności termomechanicznej i chemicznej dysz grafitowych zbudowanych z wkładki pirografitowej oraz korpusu z grafitu polikrystalicznego, na działanie produktów spalania marszowego ładunku przeciwlotniczego pocisku rakietowego GROM. We wstępnej fazie badań wykonano analizę modelu spalania heterogenicznego paliwa rakietowego tworzącego ładunek marszowy układu napędowego pocisku GROM, w określonych warunkach pracy silnika rakietowego. Rzeczywistą odporność dysz na erozyjne działanie strumienia produktów spalania określano za pomocą diagnostycznego systemu radioskopowego czasu rzeczywistego poprzez porównanie zmian profilu przekroju kanału przelotowego dyszy, a zwłaszcza średnicy krytycznej kanału przed oraz po stacjonarnych badaniach spalaniem ładunków marszowych pocisku GROM w grubościennych komorach spalania.In this paper there are presented certain aspects of investigations, analyses and assessments dealing with thermo-mechanical and chemical resistance of nozzles composed of pyrographite insert and body made from polycrystalline graphite. The nozzles were considered in terms of their thermo-mechanical and chemical resistance against combustion products of sustaining propellant charge applied in propulsion system of antiaircraft missile GROM. In initial stage of investigations, it was conducted analysis of combustion model of heterogeneous rocket propellant of composition corresponding to composition of real sustaining propulsive charge of missile GROM, under assumed conditions of rocket motor operation. Real resistance of graphite nozzles against action of combustion products, was determined by means of real time radiography (RTR) on the basis of comparison of nozzle duct section profile changes before and after static firing tests with usage of GROM missile sustaining propellant charges inserted in thick-walled combustion chamber

    The digital function filters – algorithms and applications

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    The simple digital filters are not sufficient for digital modeling of systems with distributed parameters. It is necessary to apply more complex digital filters. In this work, a set of filters, called the digital function filters, is proposed. It consists of digital filters, which are obtained from causal and stable filters through some function transformation. In this paper, for several basic functions: exponential, logarithm, square root and the real power of input filter, the recursive algorithms of the digital function filters have been determined The digital function filters of exponential type can be obtained from direct recursive formulas. Whereas, the other function filters, such as the logarithm, the square root and the real power, require using the implicit recursive formulas. Some applications of the digital function filters for the analysis and synthesis of systems with lumped and distributed parameters (a long line, phase shifters, infinite ladder circuits) are given as well

    The wave transformer – analysis and application of time digital filters and the integral-derivative operators of ½ order

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    In this paper the way of modeling phenomena occurring during the voltage and current waves passing through a point connection of two lines, with different wave impedance operators, is presented. This connection point is called „the wave transformer”. The analyzes and the resulting formulas concern not the frequency domain, but the time domain. The appropriate transition matrices of waves through the wave transformer are defined. This matrices are the convolution integral-derivative operators of fractional order (the digital filters). For a lossless line the wave transition matrices through the wave transformer become number type instead of operator type. All matrix multiplications occurring in the formulas should be understood in convolution way

    Energy-optimal current distribution in an electrical network – controlling by the differential or the integral systems

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    In the complex RLC network, apart from the currents flows arising from the normal laws of Kirchhoff, other distributions of current, resulting from certain optimization criteria, may also be received. This paper is the development of research on distribution that meets the condition of the minimum energy losses within the network called energy-optimal distribution. Optimal distribution is not reachable itself, but in order to trigger it off, it is necessary to introduce the control system in current-dependent voltage sources vector, entered into a mesh set of a complex RLC network. For energy-optimal controlling, to obtain the control operator, the inversion of R(s) operator is required. It is the matrix operator and the dispersive operator (it depends on frequency). Inversion of such operators is inconvenient because it is algorithmically complicated. To avoid this the operator R(s) is replaced by the R’ operator which is a?matrix, but non-dispersive one (it does not depend on s). This type of control is called the suboptimal control. Therefore, it is important to make appropriate selection of the R’ operator and hence the suboptimal control. This article shows how to implement such control through the use of matrix operators of multiple differentiation or integration. The key aspect is the distribution of a single rational function H(s) in a series of ‘s’ or ‘s1’. The paper presents a new way of developing a given, stable rational transmittance with real coefficients in power series of ‘s/s1. The formulas to determine values of series coefficients (with ‘s/s1’) have been shown and the conditions for convergence of differential/integral operators given as series of ‘s/s1’ have been defined

    L1-impulses method as an alternative method of harmonic components in the power theory of discrete time systems

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    The article presents the basic mathematical theory of the operational calculus of the L1-impulses in the discrete time domain. It presents the isomorphism between the rational function set of complex variable and the exponential L1 impulses set of positive and negative time domain. The paper shows how for any factorization of the rational function consisting of casual and noncasual parts can be directly obtained the N – periodic version of the original signal using for the individual components of the L1 impulses N – copy formula. It is done by the distribution of the convolution – the type admitance operator Y of electrical circuit to the two commutative convolution operators and on this basis is obtained the distribution of electrical circuit current to two components: the active current and the reactive current in the discrete time domain using the cyclic convolutions. The distribution of current in the time domain for signals significantly different from the sinusoidal is much more favorable than the distribution in the frequency domain

    Energy optimal distribution of current modulated signals in a complex linear electrical network

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    W złożonej sieci RLC oprócz rozpływu prądów wynikającego ze zwykłych praw Kirchhoffa, można otrzymać też inne rozkłady prądów wynikające z założonych kryteriów optymalizacyjnych. W publikacji [5] rozpatrzono rozkład, który spełnia warunek minimum strat energii wewnątrz sieci, nazywając go rozkładem energetycznie optymalnym. Rozkład optymalny nie jest osiągalny samoistnie, ale aby go wywołać potrzebne jest sterowanie wektorem źródeł napięciowych, prądowo zależnych wprowadzonego do zbioru oczek złożonej sieci typu RLC. Niniejsze opracowanie jest rozszerzeniem pracy [5] na przypadek, gdy sygnały wejściowe sieci elektrycznej są okresowe, zmodulowane. Przedstawiono kluczowy aspekt, dla opisanego w artykule rodzaju modulacji, tzw. rozszczepienia modulacyjnego operatora różniczkowania, uwzględniający poprawkę (zaburzenie) modulacyjną. Uzasadniając wprowadzenie czasowo zależnej poprawki modulacyjnej posłużono się wyprowadzeniem częstotliwościowym Wprowadzenie ww rozszczepienia do operatorów sterowania optymalizującego, pozwala uzyskać poprawki modulacyjne, które umożliwiają wyznaczenie optymalnego rozkładu prądów w sieci, gdy zewnętrzny wektor zasilający jest okresowy, zmodulowany.In a complex RLC network, apart from the currents flows arising from the normal laws of Kirchhoff, other distributions of current, resulting from certain optimization criteria may also be received. The article [5] examined the distribution that meets the condition of the minimum energy losses within the network, called the energy-optimal distribution. The optimal distribution is not reachable itself, but in order to trigger it off, it is necessary to introduce the control system in the current-dependent voltage sources vector, entered into a mesh set of a complex RLC network. This study is an extension of the article [5] for the case when the electrical input signals are periodic, modulated. It presented a crucial aspect of the type of modulation described in the article, so-called modulating fission of differentiation operator which takes into account the modulation amendment
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