6,854 research outputs found

    Impact of OKT3 therapy on cytomegalovirus and herpes simplex virus infections after liver transplantation

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    The purpose of this study was to analyze the impact of OKT3 on the frequency and severity of CMV and herpes simplex virus (HSV) infections in adult liver transplant recipients. OKT3 treatment is associated with a higher risk of disseminated CMV infection, particularly in patients with primary CMV infection. It also increased the frequency of symptomatic HSV infection in HSV-seropositive liver transplant recipients

    Fungal infections after liver transplantation

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    The risk factors for development of invasive fungal infections after liver transplantation were (1) longer duration of treatment with nonprophylactic IV antibiotics, (2) longer cumulative surgical time and a higher number of laparotomies, (3) an increased number of units of RBCs and fresh-frozen plasma, and (4) a series of pretransplant laboratory findings: thrombocytopenia, low T lymphocyte levels, low CD4 helper cell and lower helper/suppressor cell ratios and IgA serum levels. The significance of some of these findings is still unclear. Attention to the risk factors outlined earlier may aid both in preventing and in the early detection of invasive fungal infections after liver transplantation

    Design of two-channel PR FIR filter banks with low system delay

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    IEEE International Symposium on Circuits and Systems, Geneva, Switzerland, 28-31 May 2000In this paper, a new approach for designing two-channel PR FIR filter banks with low system delay is proposed. It is based on the generalization of the structure previously proposed by Phoong et al. Such structurally PR filter banks are parameterized by two functions α(z) and β(z) which can be chosen as linear-phase FIR or allpass functions to construct FIR/IIR filter banks with good frequency characteristics. In this paper, the more general case of using different nonlinear-phase FIR functions for β(z) and α(z) is studied. As the linear-phase requirement is relaxed, higher stopband attenuation can still be achieved at low system delay. The design of the proposed low-delay filter banks is formulated as a complex polynomial approximation problem, which can be solved by the Remez exchange algorithm or analytic formula with very low complexity. The usefulness of the proposed algorithm is demonstrated by several design examples.published_or_final_versio

    Theory and design of a class of M-channel IIR cosine-modulated filter banks

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    This letter proposes a method for designing a class of M-channel, causal, stable, perfect reconstruction (PR) IIR cosine-modulated filter banks (CMFB). The proposed CMFB has the same denominator for all its polyphase components in the prototype filter. Therefore, the PR condition is considerably simplified, and it is relatively simple to satisfy the PR and the casual-stable requirements of the IIR CMFB. Design examples show that the proposed IIR CMFB has sharper cutoff, higher stopband attenuation, and passband flatness than its FIR counterparts, especially when the system delay is small.published_or_final_versio

    New method for designing two-channel causal stable IIR perfect reconstruction filter banks and wavelet bases

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    A new method for designing two-channel causal stable IIR PR filter banks and wavelet bases is proposed. It is based on the structure previously proposed by Phoong et al. (1995). Such a filter bank is parameterized by two functions α(z) and β(z), which can be chosen as an all-pass function to obtain IIR filterbanks with very high stopband attenuation. One of the problems with this choice is that a bump of about 4 dB always exists near the transition band of the analysis and synthesis filters. The stopband attenuation of the high-pass analysis filter is also 10 dB lower than that of the low-pass filter. By choosing β(z) and α(z) as an all-pass function and a type-II linear-phase finite impulse response (FIR) function, respectively, the bumping can be significantly suppressed. In addition, the stopband attenuation of the high-pass filter can be controlled easily. The design problem is formulated as a polynomial approximation problem and is solved efficiently by the Remez exchange algorithm. The extension of this method to the design of a class of IIR wavelet bases is also considered.published_or_final_versio

    Efficient method for designing two-channel PR FIR filter banks with low system delay

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    In this paper, an efficient method for designing perfect reconstruction (PR) two-channel finite impulse response (FIR) filter banks with low system delay is proposed. It is based on the use of nonlinear-phase FIR function in a structure previously proposed by Phoong et al. The design problem is formulated as a complex polynomial approximation problem and is solved effectively using the Remez exchange algorithm with very low design complexity. Design examples show that filter banks with flexible stopband attenuation and system delay can be readily obtained by the proposed algorithm.published_or_final_versio

    Theory and design of causal stable IIR PR cosine-modulated filter banks

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    This paper proposes a novel method for designing two-channel and M-channel causal stable IIR PR filter banks using cosine modulation. In particular, we show that the PR condition of the two-channel IIR filter banks is very similar to the two-channel FIR case. Using this formulation, it is relatively simple to satisfy the PR condition and to ensure that the filters are causal stable. Using a similar approach, we propose a new class of M-channel causal stable IIR cosine modulated filter banks. Design examples are given to demonstrate the usefulness of proposed approach.published_or_final_versio

    New design method for two-channel perfect reconstruction IIR filter banks

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    In this paper, a new method for designing perfect reconstruction (PR) two-channel causal stable IIR filter banks is introduced. It is based on a structure previously proposed by Phoong et al. [2]. By using a combination of allpass and linear-phase FIR functions, the bumping problem found in the conventional structural PR filter bank is significantly suppressed. The design problem is formulated as a polynomial approximation problem and is solved effectively using the Remez exchange algorithm. Filter banks with flexible stopband attenuation and system delay can readily be obtained using the proposed algorithm.published_or_final_versio

    Designing two-channel causal stable IIR PR filter banks and wavelet bases by model order reduction and constrained optimization

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    In this paper, two methods for designing two-channel causal stable IIR PR filter banks are introduced. The first method makes use of model reduction and constrained optimization to obtain a causal stable IIR filter bank from the structural PR FIR filter bank proposed in [2]. It yields better frequency characteristics than the original FIR filter bank and avoids the dump at π/2 when allpass filters are used. Using the 1-D to 2-D transformation proposed in [2], two dimensional PR IIR filter bank can readily be obtained from these prototypes. The second method is based on constrained optimization technique using the general PR condition. Using this technique, filter banks with low system delay and flexible frequency characteristics can be designed. The technique can also be modified to design causal stable IIR dyadic wavelet bases with added regularity conditions. A number of design examples are used to demonstrate the usefulness of the proposed design methods.published_or_final_versio

    Conceptualizing international art therapy education standards

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    Art therapy programs developing around the world need an educational framework to ensure that graduates have a knowledge base and set of skills consistent with peers in other countries. Currently there are many independent education standards offered by art therapy associations in the United Kingdom, United States, Canada, Australia and New Zealand, as well as two international associations. Synthesizing these requirements reveals 12 content areas that may constitute the core of art therapy education. Even within these standards, programs developing around the world need to consider local values related to health, art, therapy and education in order to establish globally relevant and locally meaningful art therapy training programs-Hong Kong and India are offered as examples of how to adapt education standards to cultural expectations. © 2012 Elsevier Inc.postprin
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