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  • Electrical Engineering, Measurement and Control Technology  (2,974)
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  • Articles  (21,357)
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  • 1995-1999  (21,357)
  • 1945-1949
  • 1940-1944
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  • 1
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    Springer
    Circuits, systems and signal processing 14 (1995), S. 57-67 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The paper presents a simple method for solving the optimal (LQG) control problem on an infinite time horizon for linear plants described by proper rational transfer function matrices. Since the class of proper plants discussed in the paper is more general than the one commonly used, additional properties of solutions are presented. Two numerical examples illustrate the theoretical considerations. The examples have been performed on an IBM PC using the proposed algorithm. This algorithm is a part of a public ASMCS package developed by the author for analysis, synthesis, and simulations of multi-input, multi-output (MIMO) control systems.
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  • 2
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    Circuits, systems and signal processing 14 (1995), S. 135-143 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We study the behavior of a Hilbert network (i.e., a finite or countably infinite network whose variables are in a Hilbert space and in which the associated total energy is finite) whose elements are affected by perturbations. More specifically, we will give estimates for a change of the current distribution caused by (a) perturbations of the elements of the nominal network when the voltage sources are fixed, and (b) a change of voltage sources in a network whose elements are perturbed. The conditions given in our theorems imply insensitivity and robust stability of the nominal network. The applications of the results are illustrated by an example of an infinite network.
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  • 3
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    Circuits, systems and signal processing 14 (1995), S. 473-494 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A new lattice filter structure to model two-dimensional (2-D) autoregressive (AR) fields is proposed. The proposed structure utilizes and extracts the information contained in the backward prediction error fields and their delayed versions. The main idea is to use two sets of reflection coefficients corresponding to two quadrant filters and to increase the number of reflection coefficients with the order of the lattice filter. Increasing the number of reflection coefficients at each stage produces a sufficient number of independent parameters to model AR fields up to order three, which is an improvement over the existing 2-D lattice filter structures. The improvement is confirmed by computer simulations. In addition, a relationship between the reflection coefficients and the AR coefficients is derived. It is also shown that the entropy contained in the backward prediction error field vector of the proposed structure is closer to the input entropy when compared to those contained in existing 2-D lattice filters.
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  • 4
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    Circuits, systems and signal processing 14 (1995), S. 555-561 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper addresses the problem of global asymptotic stability in recursive first hyperquadrant causalm-D digital filters. A set of simple-to-check 1-D conditions necessary for stability of them-D system is given. Generalizations tov-dimensional (v〈m) subsystems are also provided. These derived conditions are useful in determining asymptotic convergence ofm-D digital filters implemented in fixed or floating point arithmetic. The set of 1-D conditions can be considered the analogous result to practical bounded input bounded output (BIBO) stability for linearm-D systems.
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  • 5
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    Circuits, systems and signal processing 14 (1995), S. 633-637 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A new efficient algorithm for calculating the weighting coefficients of maximally linear, FIR digital differentiators is presented. Simple closed-form explicit and recursive formulas are derived in a very straightforward manner. Moreover, a simple recursive equation is established, relating coefficients of two digital differentiators of adjacent ranks.
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  • 6
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    Circuits, systems and signal processing 14 (1995), S. 661-667 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper presents a sequence of pseudorandom arrays with triangular symmetry. The sequence of arrays is also pseudorandom in nature, so it can be called a pseudorandom sequence of arrays, or PRSA. A circuit for the PRSA generator is given and some interesting properties of this type of PRSA are discussed. Also, some of the concepts presented in this paper are clarified with an example.
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  • 7
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    Circuits, systems and signal processing 14 (1995), S. 1-16 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract In this paper, we present a new class of two-dimensional FIR-median hybrid (FMH) filters, which we call separable FMH filters, for image noise smoothing. In a separable FMH filter, a one-dimensional FMH filter is applied to the rows and the columns of an image successively. The deterministic properties of separable and cross window FMH filters are discussed. Under certain assumptions, it is proved that a root of a separable FMH filter is a root of the corresponding cross window FMH filter. The noise attenuating properties of a separable FMH filter are studied and compared with those of the separable median filter, the two-dimensional median filter with a square window, and the cross window FMH filter.
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  • 8
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    Circuits, systems and signal processing 14 (1995), S. 69-85 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The Chinese remainder theorem is a fundamental technique widely employed in digital signal processing for designing fast algorithms for computing convolutions. Classically, it has two versions. One is over a ring of integers and the second is over a ring of polynomials with coefficients defined over a field. In our previous papers, we developed an extension to this well-known theorem for the case of a ring of polynomials with coefficients defined over a finite ring of integers. The objective was to generalize number-theoretictransforms, which turn out to be a special case of this extension. This paper focuses on the extension of the Chinese remainder theorem for processing complex-valued integer sequences. Once again, the present work generalizes the complex-number-theoretic transforms. The impetus for this work is provided by the occurrence of complex integer sequences in digital signal processing and the desire to process them using exact arithmetic.
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  • 9
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    Circuits, systems and signal processing 14 (1995), S. 145-166 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A method to improve the stability of the forced response of a recursive digital filter with nonlinearities due to finite wordlength is presented. An analysis of applying a stability criterion on the nonlinear filter is performed by transforming the problem into a mathematical problem of finding a zero set. As a result of the mathematical analysis, one can find a maximal sector size that bounds an equivalent nonlinearity, so that stability is ensured. This sector size is influenced by the choice of the desired nonlinearity characteristic appropriate to the problem, and the amount of the input scaling needed. Another improvement of the filter's stability is obtained by adding a feedback gain, the value of which is determined by using the zero set-finding method. Simulation results showing the improved stability properties of a filter designed by this method are presented.
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  • 10
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    Circuits, systems and signal processing 14 (1995), S. 285-298 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract In this paper a fully systolic, bit level, three-port unconstrained adaptor, which constitutes the main nontrivial building block of ladder wave digital filters, is generated. The one-dimensional binary convolution is used as the underlying algorithm for the implementation of a multiplication. The Isb-first input data organization approach is adopted and thecanonical mapping methodology is used to fully systolize the unconstrained parallel three-port adaptor at the bit level with piplining period a=1. The technique is based on a transformation of the adaptor's signal-flow graph, so that unidirectional data flow takes place. A ring-systolic scheme is proposed for implementing communications among adaptors.
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  • 11
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    Circuits, systems and signal processing 14 (1995), S. 317-349 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We consider the problem of robust stochastic adaptive control of not necessarily minimum phase systems in the presence of unmodelled dynamics. Stochastic gradient algorithms with parameter projection and modified gain sequence are used for the estimation of the unknown controller parameters. Global stability of the adaptive system is achieved without requiring the strictly positive real condition and the persistency exciting condition to be satisfied.
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  • 12
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    Circuits, systems and signal processing 14 (1995), S. 427-443 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A theoretical framework for the investigation of the qualitative behavior of differential-algebraic equations (DAEs) near an equilibrium point is established. The key notion of our approach is the notion of regularity. A DAE is called regular locally around an equilibrium point if there is a unique vector field such that the solutions of the DAE and the vector field are in one-to-one correspondence in a neighborhood of this equilibrium point. Sufficient conditions for the regularity of an equilibrium point are stated. This in turn allows us to translate several local results, as formulated for vector fields, to DAEs that are regular locally around a given equilibrium point (e.g. Local Stable and Unstable Manifold Theorem, Hopf theorem). It is important that these theorems are stated in terms of the given problem and not in terms of the corresponding vector field.
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  • 13
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    Circuits, systems and signal processing 14 (1995), S. 495-524 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The classical notion of the λ-generalized nullspace, defined on a matrixA εR n×n,where λ is an eigenvalue, is extended to the case of ordered pairs of matrices(F, G), F, G ε R m×nwhere the associated pencilsF − G is right regular. It is shown that for every α εC ∪ {∞} generalized eigenvalue of (F, G), an ascending nested sequence of spaces {P α i ,i=1, 2,...} and a descending nested sequence of spaces {ie495-02 i=1, 2,...} are defined from the α-Toeplitz matrices of (F, G); the first sequence has a maximal elementM α * , the α-generalized nullspace of (F, G), which is the element of the sequence corresponding to the index τα, the α-index of annihilation of (F, G), whereas the second sequence has the first elementP α * as its maximal element, the α-prime space of (F, G). The geometric properties of the {M α i ,i=1, 2,...,τα and {P α i ,i=1, 2,...sets, as well as their interrelations are investigated and are shown to be intimately related to the existence of nested basis matrices of the nullspaces of the α-Toeplitz matrices of (F, G). These nested basis matrices characterize completely the geometry ofM α * and provide a systematic procedure for the selection of maximal length linearly independent vector chains characterizing theα-Segre characteristic of (F, G).
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  • 14
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    Circuits, systems and signal processing 14 (1995), S. 563-586 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The robustness problem of stability for large-scale uncertain systems with a class of multiple time delays is addressed in this paper. By applying the complex Lyapunov stability theorem, the matrix measure techniques, and norm inequalities, a new approach for solving a general case of the above problem is proposed. Several robust stability conditions, delay-dependent or delay-independent, are derived to guarantee the asymptotic stability and exponential stability of the uncertain large-scale time-delay systems. Moreover, these obtained results can also be applied to the stabilization design.
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    Circuits, systems and signal processing 14 (1995), S. 615-632 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Successful speech recognition is highly dependent on appropriate speech segmentation. The poor efficiency of the sequential detection of abrupt changes in the signals with relatively short stationary intervals, as is the case with speech signals, can be improved by the off-line maximum likelihood segmentation algorithm. In this paper the new segmentation algorithm is presented. For the a priori known number of segments, the algorithm determines such signal partitions for which the sum of segment distortion is minimal. The generalized maximum likelihood distortion measure has been introduced, and has proven to be particularly efficient on short signal segments. In the case of an unknown number of segments, its estimate is obtained comparing the reduction of the distortion. The asymptotic properties of the distortion sequence have been analyzed, which led to the definition of the presented segmentation algorithm. The introduced measure can be applied both to the AR and ARMA models. The segmentation algorithm is verified on test signals as well as on the natural speech signal, for which the pitch synchronous framing scheme is applied. The experimental results also include a comparison of the AR and ARMA model-based segmentations. The first results show that ARMA model-based segmentation gives somewhat better results than the AR model algorithm.
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  • 16
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    Circuits, systems and signal processing 14 (1995), S. 639-651 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A new bit-serial architecture for implementation of high order FIR filters is introduced, as well as example FPGA and CMOS realizations. This structure exploits the simplicity of coefficients that consist of two power-of-two terms to yield efficient implementations. Quantization effects are discussed and a simple block scaling method for reducing rounding and truncation noise in high order filters is also presented.
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  • 17
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    Circuits, systems and signal processing 14 (1995), S. 39-55 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper describes an implementation of 2-D FIR and IIR linear digital filters via VLSI array processors. The underlying realization structures are based on the matrix decomposition approach. The 2-D concurrent processing is used in order to implement the row and column delays within the cycle time. A high degree of concurrency is achieved by exploiting the pipelining of the array processors with the inherent parallelism of the matrix decomposition structure. The resulting structures are modular, and regular, use only local communication and internal local feedback loops, and achieve high throughput and sampling rates.
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    Circuits, systems and signal processing 14 (1995), S. 111-134 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This article studies dynamical systems under perturbations. We prove an Equilibrium Equivalence Theorem that guarantees that the dynamics of the system remains unchanged under perturbations with certain fairly general assumptions. We also prove that a power system is robust with respect to parameter changes in generic situations. Concepts of equilibrium equivalence and equilibrium equivalence structural stability are developed and are applied to studies of bifurcations of vector fields on noncompact manifolds. A constructive approach to equilibrium equivalence structural stability verification is emphasized. General results on structural stability of vector fields on differential manifolds are established and important applications of this theory to stability analysis are considered.
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    Circuits, systems and signal processing 14 (1995), S. 167-185 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The problem of designing a stabilizing compensator for a control system to achieve prescribed initial value constraintsυ (i)(0+)=yi is considered. Indeed, modulo certain technical conditions, such a compensator exists if and only if yi=0;i= 0,1,...,r〈p〉 +r〈t〉 −2; wherer〈p〉 is the relative degree of the plant andr〈t〉 is the relative degree of the system input. This theorem is derived and a complete parameterization of the set of compensators that achieve the prescribed design constraints is formulated.
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    Circuits, systems and signal processing 14 (1995), S. 255-278 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Wideband source location in array signal processing has received much attention in the literature lately. Methods such as the Coherent Signal Subspace (CSS) method proposed by Wang and Kaveh [12], and the signal subspace method used by Cadzow [3], are typical of the approaches used to tackle the multiple wideband source location problem. Most of these methods are variations of the narrowband high-resolution methods. Grenier [5], on the other hand, has applied the idea of time-dependent Auto-Regressive (AR) modeling [7] for a nonstationary process to the frequency domain AR modeling of the sensor outputs in a linear array and has been able to produce good results for a wideband signal. The AR coefficients in the model are expanded in a set of frequency-dependent basis functions. The choice of the basis functions was deemed immaterial and the method works even when only one snapshot of the array output is available. In this paper, we re-examine this method and present an extension of the frequency-dependent AR modeling approach to a planar array. It is shown that the use of a set of sinc functions for representing the frequency-dependent AR coefficients accurately tracks their evolution in the frequency domain, and gives superior performance compared to that when power or Legendre functions are used. We also propose two methods for smoothing the spatial spectra, from which the source locations are determined. Comparison with the CSS method are also presented.
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    Circuits, systems and signal processing 14 (1995), S. 17-38 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Centralized methods for source location using sensor arrays have computational and communication burdens that increase significantly with the number of sensors in the array. Therefore, these methods may not be usable in the applications involving very large arrays. In such applications, the data processing may need to be decentralized. This paper introduces two methods for decentralized array processing, based on the recently proposed MODE algorithm. For prescribed nonoverlapping subarrays, both methods are shown to be statistically optimal in the sense that asymptotically they provide the most accurate decentralized estimates of source location parameters. The problem of subarray selection to further optimize the estimation accuracy is only briefly addressed. The two methods are intended for different types of applications: the first should be preferred when there exist significant possibilities for local processing or for parallel computation in the central processor; otherwise the second method should be preferred. The accuracy of the two decentralized methods is compared to the centralized Cramér-Rao bound, both analytically and numerically, in order to provide indications about the loss of accuracy associated with decentralized processing.
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    Circuits, systems and signal processing 14 (1995), S. 87-110 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We present in this paper a recursive-in-order least-squares (LS) algorithm to compute efficiently the parameters of a 2-D Gaussian Markov random field (GMRF) model. The algorithm is based on the fact that the least-squares estimation of the parameters of a 2-D noncausal GMRF model is consistent and the coefficient matrix in the normal equation has near-to-block-Toeplitz structure. Hence, it has a Levinson-like form for the updating of model parameters by introducing auxiliary variables. Moreover, this paper proposes the concept ofrecursive path for 2-D recursive-in-order algorithms, and points out that there exists a tradeoff between fast computation of the parameters and accurate choice of model support; a compromise recursive path is then suggested where the orders change alternately in two directions. The computational complexity of the developed algorithm is analyzed, and the results show that the algorithm is more efficient when either the image size or the model support is larger. It is found that the total number of multiplications (mps) involved in the new algorithm is only about 14% of that in the conventional LS method when the image size is 512 × 512 and the neighbor set of the model is a 17 × 17 window. Computer simulation results using the recursive-in-order algorithm developed in this paper and the conventional LS method are given to verify the correctness of the new algorithm.
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    Circuits, systems and signal processing 14 (1995), S. 539-553 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Cross terms are an inherent consequence of the second order nature of Cohen's class TFDs (Time-Frequency Distributions) [5], [6]. They are manifest in a TFD of multicomponent signals as spurious artifacts arising from interactions between the various signal components, and they can often appear at times and/or frequencies inconsistent with the underlying physical nature of the signal, causing misinterpretation [2], [3], [4]. There are many time frequency distributions that avoid the cross term effect; the best are the Choi-Williams ED (Exponential Distribution) [1] and Levin's IPS (Instantaneous Power Spectrum) [9]. In this paper we combine the cross term reducing philosophy of the ED and IPS to obtain a new TFD that most effectively reduces the cross term effect. Surprisingly, the new TFD also satisfies most desired TFD properties.
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    Circuits, systems and signal processing 14 (1995), S. 669-674 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The stochastic likelihood function [(STO)LF] associated with the narrowband signal processing problem can be concentrated with respect to the signal covariance matrix elements and the noise power. Although this is a known fact, no clear-cut derivation of the concentrated (STO)LF appears to be available in the literature. In this short paper we provide a simple, complete proof of the concentrated (STO)LF formula.
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    Circuits, systems and signal processing 14 (1995), S. 725-734 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We give bounds on the self-sustained limit cycles in fixed-poin implementations of state-variable-form digital filters having general stable system matrices. These bounds, which are period independent and which concern limit cycles due to quantization errors in physical realizations of digital filters, are given in closed form for second-order sections. A numerical comparison shows that the bounds are smaller than corresponding ones reported in the literature. This is due to our use of real similarity transformations.
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    Circuits, systems and signal processing 14 (1995), S. 787-815 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We consider the concept reachability for Polynomial Matrix Descriptions (PMDs); i.e., systems of the form ∑: A(ρ)β(t)=B(ρ)u(t),y(t)=C(ρ)β(t), whereρ:=d/dt the differential operator,A(ρ)=A0+A1 ρ+...+ Av ρ v εR r×r[ρ], AiεR r×r,i=0, 1,..., ν ≥ 1 with rank R A v ≤r B(ρ) =B 0+B 1ρ+...+B σρσ εR r×m[ρ], Bi εR r×m,i=0,1,...,σ ≥ 0 C(ρ)=C0+C1 ρ+...+Cσ1 ρ σ1 εR m1×r[ρ],C i εR m1×r ,i=0, 1,..., σ1 ≥ 0, β(t): (0−, ∞) →R r is the pseudostate of (∑),u(t): [0, ∞) →R m is the control input to (∑), and y(t) is the output of the system (∑). Starting from the fact that generalized state space systems, i.e., systems of the form ∑1: Ex(t)=Ax(t)+ Bu(t), y(t)=Cx(t), whereE εR r×r, rank R E 〈r, A εR r×r,B εR r×m,C εR m1×r represent a particular case of PMDs, we generalize various known results regarding the smooth and impulsive solutions of the homogeneous and the nonhomogeneous system (∑1) to the more general case of PMDs (∑). Relying on the above generalizations we develop a theory regarding the reachability of PMDs using time-domain analysis, which takes into account finite and infinite zeros of the matrix A(s)=L.[A(ρ)]. The present analysis extends in a general way many results previously known only for regular and generalized state space systems.
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    Circuits, systems and signal processing 14 (1995), S. 445-463 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper proposes a scaling and squaring geometric series method along with the inverse-geometric series method for finding discrete-time (continuous-time) structured uncertain linear models from continuous-time (discrete-time) structured uncertain linear systems. The above methods allow the use of well-developed theorems and algorithms in the discrete-time (continuous-time) domain to indirectly solve the continuous-time (discretetime) domain problems. Moreover, these methods enhance the flexibility in modeling and control of a hybrid composite system. It has been shown that the commonly used bilinear approximation model is a specific class of the proposed geometric series model.
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    Circuits, systems and signal processing 14 (1995), S. 525-538 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Of concern is the undistorted propagation of pulse stress waves in long thin bodies. The primary signals are arbitrarily sharp pulses projected along thex-axis. It will be seen that these pulses travel close to the speed of sound in unbounded media. Secondary pulses follow representing interactive disturbances traveling along they-axis. But the process brings out certain anomalies in circuit realizability requirements. These issues, transmission parameters, and coupling between the various signals are studied in detail. The results are supported by experiments.
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    Circuits, systems and signal processing 14 (1995), S. 187-211 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper investigates circuit Markov processes under the standpoint of duality principle.
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    Circuits, systems and signal processing 14 (1995), S. 237-254 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract In this paper, a high resolution technique for estimating DOAs of spatially close source signals is presented. It is observed that the array manifold over a sector of interest is rank deficient and the dimension of the array manifold space, which is the range space of the array manifold, is less than the number of sensors in the array. The true signal subspace is a subspace in the array manifold space. A novel technique is provided that searches for the signal subspace in this array manifold space. The resulting estimated signal subspace has minimum principal angles with the data signal subspace generated by eigen-decomposing the covariance matrix of the array data vector. It is proved that the proposed estimator is asymptotically consistent and the estimated signal subspace is closer to the true signal subspace than the data signal subspace formed by MUSIC. The proposed novel technique has better performance than the MUSIC algorithm. Its performance is comparable to MLE and MD-MUSIC yet it requires only one-dimensional searches and is computationally much less intense. Simulation results are presented to show the effectiveness of the proposed technique, and comparisons with MUSIC, MLE, and MD-MUSIC algorithms are also included.
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    Circuits, systems and signal processing 14 (1995), S. 351-400 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract High-level synthesis is becoming increasingly important in the area of VLSI CAD. During the last decade, much research has been carried out in this area and some results have been achieved. This paper presents a survey on the state-of-the-art of current high-level synthesis research and applications. Besides basic knowledge, a comprehensive overview has been conducted among the various theories, methods, algorithms, and applications of the existing systems. Their advantages, limitations, and feasibilities are also described. Finally, some points on current status and future directions of high-level synthesis are addressed.
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    Circuits, systems and signal processing 14 (1995), S. 401-414 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper introduces the running kernels that yield recursive structures for time-frequency distributions (TFDs). The running kernels offer important properties not possessed by the commonly used block distribution kernels. The introduced kernels allow an invariance in computations with respect to the extent of the kernel in the time or the lag variable. However, contrary to the wide class of block kernels that satisfy the desired timefrequency (t-f) properties, most recursive (running) time-frequency distributions (RTFDs) violate the marginal and the support properties. This paper considers both the direct and the indirect types of recursion and presents examples for illustration.
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    Circuits, systems and signal processing 14 (1995), S. 465-472 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract In this paper the dual topics of robust signal detection and robust estimation of a random variable are considered, where the data may be both dependent and nonstationary. We note that classical saddlepoint techniques for robustness do not readily apply in the dependent and/or nonstationary situation, and thus our results have application in a larger domain than what was feasible heretofore. In addition, our methods make possible the quantitative measurement of robustness and admit essentially arbitrary perturbations in an underlying joint statistical distribution away from the nominal. In particular, our methods show that the presence of dependency can result in a reduction of the robustness of the linear detector by approximately 50% and that appropriate censoring can improve this situation. We also show that, somewhat surprisingly, a weak amount of censoring can actually reduce robustness rather than increase it, even with dependent data that is “almost” independent. This calls into question the common practice, inspired by classical saddlepoint results for independent data, of employing censoring in cases where residual dependency is conceded. When applied to estimation, our work shows that for nominally Gaussian data, the conditional expectation estimator is optimal not only in terms of performance but also robustness (under appropriate performance measures), thus reinforcing the appeal of this estimator. On the other hand, for other performance measures, we also note that the conditional expectation estimator can be completely unrobust, regardless of whether the data is nominally Gaussian or not. Finally, our results establish a bound on estimator robustness.
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    Circuits, systems and signal processing 14 (1995), S. 707-724 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Selection of test nodes is an important phase of the fault dictionary approach. It is demonstrated in this paper that the techniques used for this purpose in other approaches of analog fault diagnosis like fault analysis and fault verification are not in general suitable for the fault dictionary approach. The ambiguity set is a simple and effective concept for choosing test nodes in the context of dictionaries. These sets are formed such that each faulty condition lies in only one ambiguity set. Deviating from this thinking, overlapping ambiguity sets are proposed in this paper, giving rise to a generalized fault dictionary. These sets use information more fully and hence reduce the number of test nodes. The concept of hashing is applied in this paper for selecting test nodes. This gives a linear time algorithm (linear in the number of fault voltage specificationsf′) and it isf′ times faster than the existing methods. It is not possible to select test nodes faster than this. This technique can also be used to select test nodes by the process of elimination of nodes. This is also linear inf′ per node elimination. Even a group of nodes can be eliminated or selected within the same computation. This freedom is not possible with the existing methods.
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    Circuits, systems and signal processing 14 (1995), S. 689-705 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A major reason for the success of linear autoregressive (AR) modeling is that Kolmogrorov proved that every linear system could be represented by a linear AR model of infinite order. The computation of a finite order AR approximation is, of course, the practical goal. In this paper, we prove that every nonlinear system with a Volterra series expansion can be represented as a nonlinear AR model of infinite order. Our method shows how an approximation to any desired order and degree can be achieved.
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    Circuits, systems and signal processing 14 (1995), S. 213-236 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper presents an improved direct control architecture for the on-line learning control of dynamical systems using backpropagation neural networks. The proposed architecture is compared with the other direct control schemes. In this scheme the neural network interconnection strengths are updated based on the output error of the dynamical system directly, rather than using a transformed version of the error employed in other schemes. The ill effects of the controlled dynamics on the on-line updating of the network weights are moderated by including a compensating gain layer. An error feedback is introduced to improve the dynamic response of the control system. Simulation studies are performed using the nonlinear dynamics of an underwater vehicle and the promising results support the effectiveness of the proposed scheme.
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    Circuits, systems and signal processing 14 (1995), S. 299-316 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The analysis of initial value problems associated with singular linear dynamic systems using spectral methods is discussed. These methods, though extensively studied in the literature, can be very sensitive to numerical errors and to the presence of noisy input data. Moreover, using piecewise constant functions, like Walsh or Block-Pulse, spectral methods have been shown to be unstable with respect to incorrect initial conditions. In this paper regularization techniques are used to reduce arbitrarily the sensitivity of the spectral methods, and at the same time to stabilize them. Although the regularized spectral methods maintain the structure of the original algorithm, they can also be rewritten in recursive form, leading to the definition of a class of discrete time filters. Finally, some applicative numerical examples are discussed in order to show the effectiveness of the proposed algorithms.
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    Circuits, systems and signal processing 14 (1995), S. 415-425 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A complete solution is given to the problem of determining when a certain iteration will converge to the minimum of an important type of quadratic functional. It is shown that convergence occurs whenever the minimum exists, and that the iterates produced by the iteration will be unbounded for every starting point if the minimum does not exist. Applications are given concerning an adaptive filtering algorithm and nonharmonic series expansions.
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    Circuits, systems and signal processing 14 (1995), S. 587-602 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The least mean square (LMS) algorithm is investigated for stability when implemented with two's complement quantization. The study is restricted to algorithms with periodically varying inputs. Such inputs are common in a variety of applications, and for system identification, they can always be generated as shown with an example. It is shown that the quantized LMS algorithm is just a special case of a quantized periodically shift-varying (PSV) filter. Two different sufficient conditions are obtained for the bounded input bounded output (BIBO) stability of the PSV filter. When the filter is BIBO stable, two different bounds on the filter output are also derived. These conditions and bounds are then applied to the quantized LMS algorithm. The results are illustrated with examples.
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    Circuits, systems and signal processing 14 (1995), S. 603-614 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract An improved version of the Fast Polynomial Transform for the computation of two-dimensional cyclic convolutions is proposed in this paper. This new version of the Fast Polynomial Transform comes from the concept of splitting product-fields and gives more than a 20% to 50% reduction in the numbers of multiplications. An average of 20% improvement on overall computation time compared with the previous approach is also achievable.
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    Circuits, systems and signal processing 14 (1995), S. 653-660 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract An algorithm is presented for the spectrum of experimentally obtained exponentially damped sinusoidal signals. The implementation of this algorithm is straightforward and requires only simple basic mathematical operations. Applications of the algorithm are illustrated by several examples.
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    Circuits, systems and signal processing 14 (1995), S. 675-688 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Exact analysis of second-order sigma-delta modulators with constant input is presented. Some properties of general limit cycles are established. Sufficient conditions for the existence of a general class of limit cycles of the state vectors of the modulator are determined. The conditions interrelate the input, an initial vector, and the period of the limit cycle. Also, sufficient conditions are determined for a class of initial condition vectors to converge to a limit cycle.
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    Circuits, systems and signal processing 14 (1995), S. 735-747 
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    Notes: Abstract A weighted median filter is a nonlinear digital filter consisting of a window of length 2N + 1 and a weight vector W=(W− N,..., W0,..., WN). A root signal of a median type filter is a signal that is invariant to the filter. However, not all weighted median filters possess the convergence property. In this paper, we shall study the root structures and the convergence behavior of a subclass of weighted median filters, calledclass- 1 filters, which is symmetric in its weight vector. We shall introduce an important parameter, calledfeature value, and show that any one-dimensional unappended signal of lengthL will converge to a root signal in at most $$3\left\lceil {\frac{{L - 2}}{{2(2N + 2 - p)}}} \right\rceil$$ passes of aclass −1 filter with window width 2N + 1 and thefeature value p.
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    Circuits, systems and signal processing 14 (1995), S. 771-786 
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    Notes: Abstract A multirate modeling theory of the ARMA stochastic signals is derived from a state-space viewpoint in this work. Its application to the signal reconstruction problem for the recovery of the complete ARMA signal from its noise-corrupted, missing-sample sequence is then developed in detail. The proposed estimation-interpolation problem can be resolved by using the multirate optimal state estimation scheme of this work. Theoretically, the multirate Kalman reconstruction filters derived in this paper produce the minimum variance estimation and interpolation of the original complete, clean ARMA signal. Practically, the numerical examples show that the multirate Kalman reconstruction filters illustrate good estimation/interpolation performances, not only for synthetic ARMA sequences but also for human speech signals.
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    Circuits, systems and signal processing 14 (1995), S. 817-825 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The necessary and sufficient conditions for the invariance of theU-function of a linear time-invariant two-port network under lossless nonreciprocal imbedding are given in terms of the anti-Hermitian property of the immittance matrix of the imbedding network.
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    Circuits, systems and signal processing 14 (1995), S. 749-770 
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    Notes: Abstract The mean-square error (MSE) of Capon estimate of the directions-of-arrival (DOA) is established in the narrowband array processing case. An improved Capon-like DOA estimator is proposed and its MSE is studied as well. Performance comparisons between the standard and improved Capon DOA estimates, and between these two estimates and the linear prediction DOA estimate, are performed. It is concluded that the improved Capon-like method introduced in this paper provides more accurate DOA estimates in most cases.
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    Polymer bulletin 35 (1995), S. 649-652 
    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Water molecules sorbed in pure poly(vinyl alcohol) and poly(vinyl pyrrolidone), as well as in their blends is found to be only partially crystallizable. The fraction of noncrystalizable water is shown to vary with the blend composition. Such variation is explained by the newly proposed Tg-regulation effect when the swollen blend materials is cooled down. A part of the sorbed water cannot crystallize due to the fact that during cooling the amorphous polmer-water phase is frozen before the water crystallization temperature is reached.
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    Polymer bulletin 35 (1995), S. 641-648 
    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The low temperature relaxation of epoxy resin modified with siloxane oligomers was investigated by using thermally stimulated current (TSC) and relaxation map analysis (RMA). The β-relaxation of epoxy resin and the glass transition temperature of siloxane oligomer were folded and shifted to higher temperature as the concentration of trifluoropropyl (TFP) in siloxane oligomer increased. In the systems containing over 50% of TFP a new relaxation peak due to the dipole orientation was observed at around-45°C. As the concentration of TFP increased the compensation temperature (Tc) and the degree-of-disorder (DOD) were increased while the compensation time, τc was decreased.
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    Polymer bulletin 35 (1995), S. 653-658 
    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The title monomers were synthesized via Wittig reaction from thujone and pugelone. The monomers were found to react rapidly with cationic initiators at temperatures from -15° to 22°C. The products of these reactions were found to be low molecular weight oligomers. The reaction temperature, presence of solvent or initiator type and concentration seemed to have some effect on the molecular weights of the products obtained.
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  • 50
    ISSN: 1436-2449
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    Notes: Summary Poly[(N,N-dicarboxymethyl)allylamine] as a water-soluble polymeric chelating agent was prepared by carboxymethylation of poly(allylamine) (PAA) with chloroacetic acid or bromoacetic acid. The 1H-NMR, IR, and elementary analyses showed that the iminodiacetic group was introduced quantitatively into the amino group of PAA. Chelating properties of this polymeric chelating agent toward Cu2+, Ni2+, Zn2+, and Ba2+ were examined by potentiometric titration.
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    ISSN: 1436-2449
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    Notes: Summary N-Vinyl phthalamide was copolymerized with methyl methacrylate, isobutyl methacrylate or butyl acrylate. The copolymerizations were initiated free radically and it was necessary to conduct the polymerizations in solution or else insoluble products would result. In most cases the polymerizations preceded to relatively high conversions in a short time. The conversions necessitated the use of high conversion methods to calculate the reactivity ratios. The N-vinyl phthalamide was found to be the less reactive monomer in all cases. As part of this study, poly(N-vinyl phthalamide) homopolymer was synthesized by free radical initiation. While the 1H-NMR spectrum yield very little information concerning polymer stereochemistry, the methine carbon resonance in the 13C-NMR spectrum displayed a sensitivity to polymer stereochemistry.
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    Polymer bulletin 35 (1995), S. 671-676 
    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Three new monomers for cyclopolymerization were synthesized using phase transfer catalysis of ethyl α-(chloromethyl) acrylate (ECMA), t-butyl α-(bromomethyl) acrylate (TBBMA) and isobornyl α-(bromomethyl)acrylate (IBBMA) with cinnamic acid sodium salt. Bulk and solution polymerization at 70–80°C using AIBN gave soluble cyclopolymers with Mn=13650 and Mw=36540 for the ethyl ester, Mn=47700 and Mw=86900 for the t-butyl ester and Mn=3500 and Mw=4650 for the isobornyl ester monomer. The ester polymerizabilities decreased with increasing substituent bulkiness. FTIR spectra showed ca 30 to 93% cyclic units depending on the concentration of the monomer used in polymerizations. DSC thermograms showed that alkyl group size had little effect on Tg's, with values of 151°C, 156°C, and 164°C for the ethyl, t-butyl and isobornyl esters, respectively.
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    Polymer bulletin 35 (1995), S. 683-689 
    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A novel well-defined macromonomer consisting of different types of monomers in polymerization mechanisms was synthesized for the first time through the SmI2-induced transformation. The macromonomer, ω-methacryloylpoly-(tetrahydrofuran-b-ε-caprolactone), was prepared by the reaction of methacryloyl chloride with living poly(tetrahydrofuran-b-ε-caprolactone) [poly(THF-b-CL)] which was obtained by the two-electron reduction of the cationic growing center of poly(THF) by samarium iodide (SmI2) followed by the polymerization of CL. 1H NMR analysis indicated the quantitative introduction of the methacryloyl group onto the polymer end. The molecular weight distribution of the macromonomer was relatively narrow, and the unit ratio of THF to CL could be controlled by both polymerization time of THF and the amount of CL, resulting from the living nature of both CL- and THF-polymerizations. Radical copolymerization of the produced macromonomers with methyl methacrylate in the presence of AIBN resulted in a polymethacrylate backbone grafted with poly(THF-b-CL) block copolymers.
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    ISSN: 1436-2449
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    Notes: Summary Poly[2-(2-(4-(trifluoromethyl)phenyl)ethenyl)-5-methoxy-1,4-phenylenevinylene] (PFEMPV) and a series of PPV copolymers containing 1,4-phenylenevinylene (PV) units were synthesized through a water-soluble precursor route, and their electrical and third-order nonlinear optical properties were studied. The PFEMPV films could not be doped with I2, but FeCl3-doped films showed an electrical conductivity of 5.0x10-4 S/cm. The conductivities of FeCl3-doped copolymer films ranged from 2.0x10-3 to 2.0 S/cm depending on their copolymer compositions. The third-order nonlinear optical susceptibility, χ(3)(−ω;ω,ω,−ω), was also investigated by the degenerate four wave mixing technique at 602 nm. The χ(3) value of PFEMPV was 6.9x10-11 esu. The photoluminescence spectrum of PFEMPV shows its emission maximum at 550 nm.
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    Polymer bulletin 35 (1995), S. 705-710 
    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A new route for the preparation of soluble fullerenated polymer through the reaction of carbanion intermediates of polymers with fullerenes, particularly C60, is demonstrated. Confirmation of the covalent attachment of C60 to the polystyrene backbone is by a variety of techniques such as UV-Vis, FT-IR, TGA, SEM and 13C NMR etc. The product, which has a visibly brownish yellow cast when compared with the unreacted polymer, is soluble in some common organic solvents. The thermal stability of pure polystyrene is enhanced by C60-chemical modification, and no bonds within the carbon sphere are broken.
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    Polymer bulletin 35 (1995), S. 711-718 
    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The title monomer was polymerized in solution via free radical initiation. The polymer's 300 MHz 1H-NMR and 75.5 MHz 13C-NMR spectra were recorded and analyzed in terms of polymer stereochemistry. Most of the resonances in both the 1H-NMR and 13C-NMR spectra showed multiplicity consistent with sensitivity to polymer stereochemistry. However the 13C-NMR spectrum proved somewhat easier to interpret. The analysis of both the 1H-NMR and 13C-NMR spectra very strongly indicate that poly(3-methyl-1-vinylpyrazole) is an atactic polymer.
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  • 57
    ISSN: 1436-6215
    Keywords: Kraftsportler ; hohe Proteinzufuhr ; renale Nettosäureausscheidung ; Urin pH ; Ammoniumausscheidung ; Ammoniumproduktion ; renale Säureausscheidungskapazität ; Sulfat ; Bodybuilder ; high protein diet ; renal net acid excretion ; urine-pH ; ammonium excretion ; ammonia production ; sulfate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Bodybuilders often prefer a high protein diet to achieve maximum skeletal muscle hypertrophy. In this study the effect of a high protein diet on renal acid load and renal handling of proton excretion was studied comparing dietary intake and urinary ionograms in 37 male bodybuilders and 20 young male adults. Energy intake (+7 %), protein intake (128 vs 88 g/d/1.73 m2), and renal net acid excretion (95 vs 64 mmol/d/1.73 m2) were higher in the bodybuilders than in the controls, however, urine-pH was only slightly lower (5.83 vs 6.12). In the bodybuilders renal ammonium excretion was higher at any given value of urine pH than in the controls. In a regression analysis protein intake proved to be an independent factor modulating the ratio between urine-pH and renal ammonium excretion. The concomitant increase of renal net acid excretion and maximum renal acid excretion capacity in periods of high protein intake appears to be a highly effective response of the kidney to a specific food intake leaving a large renal surplus capacity for an additional renal acid load.
    Notes: Zusammenfassung Kraftsportler ernähren sich zur Förderung des Muskelwachstums häufig proteinreich. In dieser Studie wurde die Wirkung einer hohen Proteinzufuhr auf die renale Säurelast und die renale Säureausscheidungskapazität anhand des Vergleichs der Daten der Nährstoffzufuhr und der Harnionogramme von 37 Kraftsportlern mit hoher Proteinzufuhr und 20 jungen Erwachsenen mit normaler Proteinzufuhr (Vergleichsgruppe) untersucht. Die Kraftsportler zeigten eine höhere Energie-(+7 %) und Proteinzufuhr (128 vs 88 g/d/1.73 m2) und eine höhere renale Nettosäureausscheidung (95 vs 64 mmol/d/1.73 m2) als die Vergleichsgruppe. Die Differenz der Urin pH-Werte der beiden Gruppen war allerdings erstaunlich gering (5.83 vs 6.12). Bei den Kraftsportlern war die renale Ammoniumausscheidung bei allen Urin pH-Werten deutlich höher als bei der Vergleichsgruppe. Eine Regressions-analyse ergab, daß die Proteinzufuhr das Verhältnis von Urin pH und renaler Ammoniumausscheidung eigenständig zu beeinflussen vermag. Eine vermehrte Proteinzufuhr führt zu einer erhöhten renalen Säurelast und Nettosäureausscheidung. Die gleichzeitig auftretende Steigerung der renalen Säureausscheidungskapazität infolge einer erhöhten Ammoniumproduktion stellt einen sinnvollen Anpassungsmechanismus des Körpers an diese besondere Form der Ernährung dar, der dem Körper eine ausreichende funktionelle Reservekapazität für weitere den Säure-Basen-Haushalt belastende pathophysiologische Ereignisse erhält.
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    European journal of nutrition 34 (1995), S. 160-163 
    ISSN: 1436-6215
    Keywords: Immunglobulin G ; Dotterantikörper ; Intestinale Absorption ; Kalb ; Immunoglobulin G ; yolk antibodies ; intestinal absorption ; calf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Studying the prophylactic effects of specific yolk antibodies against diarrhea in newborn calves, also the intestinal absorption of unspecific heterogeneous avian antibodies as well as their effects on the uptake of maternal bovine colostral antibodies (bIgG) was investigated. Two groups of newborn calves received egg powder (16 g or 8 g per day) for the first 10 days of their life beginning with the first meal. A third group was kept as a control without any egg powder in their diet. Blood samples (5 to 10 calves per sampling time) were taken from 123 calves at 6, 12, 24, 48, or 96 h postnatally. With both doses the highest chicken IgG (cIgG) levels (3.1 µg resp. 1.2 µg per ml serum) have been measured 12 h after birth. These concentrations decreased continuously to the levels of 1.1 µg resp. 0.2 µg cIgG per ml serum at 96 h postnatally. The uptake into blood at 6 h postnatally has roughly been estimated as approximately 23 % (bIgG) and 7 % resp. 6 % (cIgG) of the IgG dosages given with the first meal. The time-course (6 to 96 h) of the bIgG level in blood was quite stable, plateauing already after 6 h at a mean of 5.9 mg per ml serum. Significant differences between the bIgG levels of calves with yolk antibodies in their diet (6.2 resp. 6.1 mg bIgG per ml serum) and those of the control group (5.4 mg per ml serum) could not be observed. Obviously, the prophylactic use of egg powder in newborn calves has no negative effect on the absorption of colostral antibodies. However, with the feeding of chicken egg yolk antibodies already with the first meal also the absorption of avian antibodies has to be taken into consideration.
    Notes: Zusammenfassung Im Rahmen einer Untersuchung zur prophylaktischen Wirksamkeit von spezifischen Dotterantikörpern bei erregerbedingten Kälberdurchfällen wurde auch die Absorption der unspezifischen heterologen aviären Dotterantikörper (cIgG) und deren Wirkung auf die Aufnahme von maternalen bovinen Kolostrumantikörpern (bIgG) überprüft. Zwei Gruppen von neugeborenen Kälbern wurde sprühgetrocknetes Volleipulver ab der ersten Tränke in einer Dosierung entweder von 16 g oder von 8 g pro Tag während der ersten 10 Lebenstage verabreicht. Eine dritte Gruppe diente als Kontrolle und erhielt kein Eipulver. Von insgesamt 123 Kälbern (5 bis 10 Kälber pro Entnahmezeitpunkt) wurden 6, 12, 24, 48, 72 bzw. 96 Stunden post natum Blutproben genommen. Bei beiden Eipulverdosierungen wurden die höchsten Hühner-IgG-Konzentrationen (3,1 µg bzw. 1,2 µg pro ml Serum) jeweils 12 Stunden post natum ermittelt. Diese cIgG-Konzentrationen nahmen danach kontinuierlich auf Konzentrationen von 1,1 µg bzw. 0,2 µg pro ml Serum zum Zeitpunkt 96 Stunden post natum ab. Bezogen auf die mit der ersten Tränke verabreichte bIgG- bzw. cIgG-Menge wurde überschlagsweise zum Zeitpunkt 6te Lebensstunde eine Anflutung im Blut von 23 % (bIgG) bzw. von 7 % und 6 % (cIgG) errechnet. Der zeitliche Verlauf (6te bis 96te Stunde) der Konzentration des bovinen IgGs in den Blutproben war vergleichsweise stabil und lag durchschnittlich bei 5,9 mg pro ml Serum, wobei das Plateau bereits nach 6 Stunden erreicht war. Signifikante Unterschiede zwischen den bIgG-Werten der Kälber, die Dotterantikörper bekamen (6,2 bzw. 6,1 mg pro ml Serum), und denen der Kontrollgruppe (5,4 mg pro ml Serum) waren nicht zu beobachten. Eipulver kann somit offensichtlich zur Prophylaxe bei neugeborenen Kälbern ohne Beeinträchtigung der Absorption der kolostralen Antikörper verabreicht werden. Allerdings muß bei einer Eipulververgabe mit der ersten Tränke auch mit einer Absorption von aviären Dotterantikörpern gerechnet werden.
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  • 59
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    European journal of nutrition 34 (1995), S. 190-197 
    ISSN: 1436-6215
    Keywords: Verzehrserhebungen ; Nationale Verzehrsstudie ; Lebensmittelverzehr ; internationaler Vergleich von Verzehrserhebungen ; Dietary surveys ; national food consumption study ; food intake ; international comparison of dietary surveys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Referring to the data of the National Food Consumption Study in Germany and the Dietary and Nutritional Survey of British Adults, this article compares the food intake of German and British adults. Such a comparison is possible because both studies have mainly the same methodology. The comparison of the food intake of German and British adults points out food groups which Germans consume inhigher amounts than British people do. To this category belong meat products and sausages, eggs, cheese and cottage cheese, butter, fat for cooking and salad oil, bread and pastries, vegetables, fruit, preserves and soft drinks. The Germans consumeless meat, fish and fish products, milk and milk products, pasta, rice and miscellaneous cereals, potatoes, sugar, sweets and tea than the British people do. The consumption of fruit products, alcoholic beverages and coffee is nearly the same in Germany and Great Britain.
    Notes: Zusammenfassung Anhand der Nationalen Verzehrsstudie und des „Dietary and Nutritional Survey of British Adults“ wird der Lebensmittelverzehr der Erwachsenen in Deutschland und Großbritannien verglichen. Dies ist möglich, weil die Methodik weitgehend übereinstimmt. Beim Vergleich des Lebensmittelverzehrs von Deutschen und Briten fallen Lebensmittel auf, von denen die Deutschenmehr zu sich nehmen als die Briten. Dazu gehören Fleisch- und Wurstwaren, Eier, Käse und Quark, Butter, Speisefette und -öle, Brot und Backwaren, Gemüse, Obst, Marmelade/Konfitüre und alkoholfreie Getränke. Die Deutschen nehmen dagegenweniger Fleisch, Fisch und Fischwaren, Milch und Milchprodukte, Nährmittel, Kartoffeln, Zucker, Süßwaren und Tee zu sich als die Briten. Beim Konsum von Obstprodukten, alkoholischen Getränken und Röstkaffee herrschen nur geringfügige Unterschiede zwischen Deutschen und Briten.
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  • 60
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    European journal of nutrition 34 (1995), S. 206-213 
    ISSN: 1436-6215
    Keywords: Fischöl ; Olivenöl ; Überernährung ; Sauen ; Energiebilanz ; Thermogenese ; Gaswechsel ; Fish oil ; olive oil ; overfeeding ; sows ; energy balance ; thermogenesis ; gaseous exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary A trial on total metabolism was conducted in eight nonpregnant, nonlactating sows over eight periods, each of 16 days duration, to measure potential fatty acid induced thermogenesis. During the first and last experimental periods, the animals received a basal ration which just covered the energy maintenance requirement. In the second to seventh periods supplements of olive oil, fish oil, or puffed wheat starch as reference nutrient were added to the diet in random sequence at two levels up to 50 % above the maintenance requirement. All rations were calculated with reference to the sows' initial weight and remained quantitatively unchanged throughout the experiment. The animals were fed twice daily. During each metabolism period a complete energy balance was assessed for all sows by means of collection technique (feed, feces, urine), and 48-h measurements of the gas exchange in a respiration chamber. The sows' body mass increased linearly during the course of the experiment by 5.8 kg per period. The three supplement types had no influence on the animals' final body weight, wich averaged 205.5 kg with the starch supplement, 204.8 kg with olive oil, and 205.8 kg with fish oil. Energy digestibility (DE/GE) was 100 % for all three supplements, and metabolizability of energy (ME/GE) one percentage point less. Carbon and energy depositions showed a pronounced linear relationship to the level of supplementation and were also influenced by the type of supplement. Heat production was 20.9 MJ/d after feeding the basal ration alone and, taking the average of the two supplementation levels, 21.6 MJ for the starch supplement, 21.0 MJ for olive oil, and 20.6 MJ for fish oil. The relationship between energy deposition and the supply of ME resulted in regression coefficients of 0.9 MJ/MJ after feeding starch and 1.0 MJ/MJ after feeding the two oils. It can be concluded from these results that supplementation of the diet with fat containing mono- or polyunsaturated fatty acids above the energetic maintenance requirement under conditions of severely restricted movement (respiration chamber) has no influence on thermogenesis and consequently causes a deposition of energy equivalent to the amount supplied with the dietary fat.
    Notes: Zusammenfassung Zur Messung einer fettsäureninduzierten Thermogenese wurde ein Gesamtstoffwechselversuch mit 8 nichtgraviden, nichtlaktierenden Sauen über 8 Perioden von jeweils 16 Tagen Dauer durchgeführt. Die Tiere erhielten in der ersten und letzten Versuchsperiode eine den energetischen Erhaltungsbedarf deckende Grundration. In Periode 2 bis 7 wurden in zufälliger Reihenfolge Olivenöl, Fischöl bzw. als Referenznährstoff Weizenquellstärke in jeweils 2 Mengenstufen bis 50 % über das Erhaltungsniveau zugelegt. Alle Rationen wurden aufgrund der Anfangsmasse der Sauen eingestellt und über den gesamten Versuch in unveränderter Menge beibehalten. Die Fütterung erfolgte zweimal täglich. Von allen Tieren wurde in jeder Stoffwechselperiode eine vollständige Bilanzmessung mit Sammeltechnik (Futter, Kot, Harn) und 48stündiger Messung des Gaswechsels in der Respirationskammer durchgeführt. Die Körpermasse der Sauen stieg im Versuchsablauf linear um 5,8 kg je Zulageperiode an. Die drei Zulagearten hatten keinen Einfluß auf die Körpermasse der Tiere, sie wogen im Mittel bei Stärkezulage 205,5 kg, bei Olivenöl und Fischöl 204,8 bzw. 205,8 kg. Die Verdaulichkeit der Energie (DE/GE) betrug bei allen drei Zulagen 100 %, die Umsetzbarkeit der Energie (ME/GE) einen Prozentpunkt weniger. Der Kohlenstoffund Energieansatz zeigte eine ausgeprägte lineare Abhängigkeit zur Zulagenhöhe sowie einen signifikanten Effekt der Zulagenart. Die Wärmebildung betrug bei alleiniger Fütterung der Grundration 20,9 MJ und im Mittel der beiden Zulagestufen bei Stärkefütterung 21,6 MJ und bei Olivenöl und Fischöl 21,0 bzw. 20,6 MJ/d. Die Abhängigkeit des Energieansatzes von der Zufuhr an ME ergab Regressionskoeffizienten von 0,9 MJ/MJ bei Verabreichung von Stärke und 1,0 MJ/MJ bei Fütterung der beiden Öle. Aus den Ergebnissen ist zu folgern, daß eine Zulage von Fetten mit einfach oder mehrfach ungesättigten Fettsäuren über dem energetischen Erhaltungsbedarf unter der Bedingung stark eingeschränkter Bewegungsaktivität (Respirationskammer) keinen Einfluß auf die Thermogenese und somit einen energetischen Ansatz entsprechend der zugeführten Energie des Nahrungsfettes bewirkt.
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  • 61
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    European journal of nutrition 34 (1995), S. 269-276 
    ISSN: 1436-6215
    Keywords: Iod ; Uriniod ; Quotient Uriniod/Urinkreatinin ; Iodresorption ; Iodbioverfügbarkeit ; Nahrungsiod ; Iodine ; urinary iodine ; quotient iodine in urine/creatinine in urine ; iodine absorption ; iodine bioavailability ; alimentary iodine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The standard food for our volunteers, prepared in the central kitchen of the University Hospital of Tuebingen, consisted of breakfast, warm lunch and cold supper and contained, on average, approximately 230 µg of iodine/day. It is generally assumed that an equilibrium is established between iodine intake from food and urinary iodine excretion. Hence, the amount of iodine excreted with the urine within 24 h may reflect the daily ingestion of iodine. The fecal iodine losses are considered negligible. The alimentary iodine supply from food of our clinic would meet the WHO recommendations of 〉150 µg/day to prevent iodine-deficiency goiters. In 27 healthy volunteers the daily uptake of iodine was determined and the urinary excretion of iodine within 24 h was measured. Unexpectedly, only 16 % to 18 % of the alimentary iodine were excreted with the urine. Hence, the utilization of iodine from the food appears to be limited and therefore cannot prevent goiters in goiter areas. In addition, it was found that the correlation between urinary excretion of iodine and urinary excretion of creatinine is not a reliable parameter for the real daily excretion of iodine and iodine balance.
    Notes: Zusammenfassung Die Verpflegung (Frühstück, Mittagessen und Abendessen) aus der Zentralküche des Universitätsklinikums in Tübingen enthält durchschnittlich 230 µg Iod/Tag. Bei Personen, die täglich an dieser Verpflegung teilnehmen, stellt sich ein Gleichgewicht zwischen Iodaufnahme und renaler Iodausscheidung ein. Die Iodausscheidung über die Faeces gilt als vernachlässigbar. Die in unserer Klinikverpflegung angebotene Iodmenge entspricht dem von der WHO geforderten Angebot von 〉150 µg Iod/Tag, um endemische Strumen zu verhindern. Bei 27 gesunden Probanden wurden die tägliche Iodaufnahme und die zugehörige Ausscheidung von Iod im 24-h-Urin ermittelt. Dabei zeigte sich überraschend, daß vom angebotenen Iod nur 16 % bis 18 % mit dem Urin ausgeschieden wurden. Das mit der Nahrung angebotene Iod steht offenbar dem Organismus nur begrenzt zur Verfügung und kann Strumen in Iodmangelgebieten nicht verhindern. Der Bezug der Uriniodausscheidung auf das Kreatinin liefert nur einen groben Parameter für die tägliche Iodausscheidung und für die Iodbilanzierung.
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  • 62
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    European journal of nutrition 34 (1995), S. 261-268 
    ISSN: 1436-6215
    Keywords: Auswahl von Mahlzeiten ; Einschätzung von Mahlzeiten ; Gesundheitswert ; Entwicklungsstand ; Ernährungserziehung ; Selection of meals ; estimation of meals ; value of health ; age differences ; education of nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary With regard to the reported knowledge concerning the health value of food in 9–10-year-old children (DGE, 1984) the question arose of whether this knowledge is also valid if pupils have to evaluate meals. Twenty-seven photos of meals (9 each of breakfast, lunch and supper) were presented to 252 children of the age groups 6–7, 9–10 and 12–13 years. By means of these photos, they were requested to organize their meals for 3 days. Subsequent to this procedure the children were asked to evaluate the meals with regard to their health value. The presented meals were classified by five experts of nutrition as more healthy, indifferent and less healthy. The results showed an improved selection of more healthy meals with increasing age. Likewise, the selection of meals for lunch and supper was better than the one for breakfast. There were no differences between boys and girls and children with and without experience of dieting. The evaluation of more healthy and less healthy meals demonstrated an improvement with increasing age. In contradiction to these results, children within all age groups showed a very low level of estimation (10 %) for indifferently classified meals and this level did not improve with increasing age. The results were discussed concerning the establishment of an appropriate education of nutrition with regard to the developmental stage and the emotional and motivational engagement of the children.
    Notes: Zusammenfassung Im Hinblick auf die relativ gute Bewertung einzelner Nahrungsmittel durch 9–10jährige Kinder (DGE, 1984) stellte sich die Frage, ob dieses Wissen gleichfalls für die Einschätzung von Mahlzeiten gilt. 252 Kinder der Altersgruppe 6–7 Jahre, 9–10 Jahre und 12–13 Jahre wurden daher 27 Fotos von Mahlzeiten (je 9mal Frühstück, Mittagessen und Abendbrot) vorgelegt. Die Kinder wurden aufgefordert, ihre Mahlzeiten auf der Basis der vorgelegten Fotos für 3 Tage zusammenzustellen. Danach wurden die Kinder befragt, wie sie die Mahlzeiten bezüglich ihres Gesundheitswertes einschätzen würden. Die vorgelegten Mahlzeiten waren von 5 Experten zuvor als „eher gesund“, „mittelmäßig gesund“ und „eher ungesund“ eingestuff worden. Die Ergebnisse weisen auf eine häufigere Auswahl „eher gesunder“ Mahlzeiten mit ansteigendem Alter hin. Die Auswahl für das Mittagessen und das Abendbrot war unter dem Aspekt des Gesundheitswertes in allen Altersstufen besser als die Auswahl für das Frühstück. Es zeigten sich keine deutlichen Unterschiede zwischen Jungen und Mädchen und Kindern mit und ohne Diäterfahrung. Die Einschätzung der „eher gesunden“ bzw. „eher ungesunden“ Mahlzeiten verbesserte sich gleichfalls mit zunehmendem Alter. Andererseits fand sich bei der Einschätzung der als „mittelmäßig gesund“ eingestuften Mahlzeiten ein recht niedriges Niveau in der richtigen Einschätzung (etwa 10 %) auf allen 3 Altersstufen. Die Ergebnisse werden im Zusammenhang mit gegenwärtigen und künftigen Maßnahmen in der Ernährungserziehung diskutiert, wobei aufgrund der Ergebnisse Entwicklung und Motivation und die emotionalen Bedürfnisse der Kinder stärker zu berücksichtigen sind.
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  • 63
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    European journal of nutrition 34 (1995), S. 166-166 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 64
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    European journal of nutrition 34 (1995), S. 167-176 
    ISSN: 1436-6215
    Keywords: Vitamin C ; Vitamin E ; β-Carotin ; antioxidative Vitamine ; Vitaminaufnahme ; Augenlinse ; Katarakte ; Alter ; Vitamin C ; vitamin E ; β-carotene ; antioxidant vitamins ; vitamin intake ; ocular lens ; cataracts ; elderly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Senile cataract indicates the opacity of ocular lenses occuring in old and especially in very old people. Lens proteins are extremely long-living and often show oxidative damages. Aging and smoking appear to be the greatest risk factors for the development of lens opacities. The sufficient antioxidant protection of young lenses decreases with the aging process. Consequently, the importance of other protective factors increases. Nutritional factors, particularly vitamins with antioxidant properties, may influence the development of senile cataracts in the ocular lens. Meanwhile an association between the supply with vitamin C, E and β-carotene and the risk of cataract development was demonstrated in animal studies and also in an increasing number of epidemiological studies. These epidemiological studies mainly support the hypothesis that higher vitamin intakes reduce the risk of developing cataracts in old age. The antioxidant properties of the named nutrients give a plausible explanation for the mechanism of cataractogenesis. On the basis of the present data definitive recommendation, necessary for cataract prevention can not yet be established. Some results seem to support higher recommendations. At the moment several large human intervention trials are carried out. Form these studies a further confirmation of the antioxidant hypothesis and of a dose-response-relationship are expected.
    Notes: Zusammenfassung Die senile Katarakt ist eine im Alter und besonders häufig im hohen Alter auftretende Trübung der Augenlinsen. Die extrem langlebigen Linsenproteine weisen häufig oxidationsbedingte Schädigungen auf. Altern und Rauchen erscheinen als die größten Risikofaktoren für eine Kataraktbildung. Während junge Augenlinsen in der Regel über eine ausreichende antioxidative Schutzkapazität verfügen, nimmt diese mit dem Alter ab. Damit wächst die Bedeutung anderer Schutzfaktoren. Nahrungsfaktoren, besonders Vitamine mit antioxidativen Eigenschaften, schützen möglicherweise vor einer Bildung von senilen Katarakten in den Augenlinsen. Ein Zusammenhang zwischen der Versorgung mit Vitamin C, E und β-Carotin und dem Kataraktrisiko konnte in tierexperimentellen Untersuchungen aufgezeigt und inzwischen auch in einer wachsenden Zahl epidemiologischer Studien nachgewiesen werden. Die bisher vorliegenden epidemiologischen Studien unterstützen mehrheitlich die Hypothese, daß erhöhte Vitaminaufnahmen das Risiko einer Kataraktbildung reduzieren. Die antioxidative Wirkung der genannten Nährstoffe liefert eine plausible Erklärung für den Mechanismus der Kataraktgenese. Es fehlen aber noch Studien, aus denen sich die für eine Prävention notwendigen Vitaminmengen ableiten lassen. Einige Untersuchungsergebnisse sprechen möglicherweise dafür, daß diese über den bisher geltenden Empfehlungen liegen. Zur Zeit werden verschiedene, große Interventionsstudien durchgeführt, die eine weitere Absicherung der Antioxidanshypothese und von Dosis-Wirkungsbeziehungen erwarten lassen.
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  • 65
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    European journal of nutrition 34 (1995), S. 240-242 
    ISSN: 1436-6215
    Keywords: Iodine ; iodized salt ; canteen ; lunch meals ; sodium chloride ; Jod ; jodiertes Speisesalz ; Großküche ; Mittagessen ; Natriumchlorid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung In zwei Universitäts-Großküchen, die für die Nahrungszubereitung jodiertes Speisesalz immer (Mensa A) oder nie (Mensa B) verwendeten, wurden 15 möglichst gleiche Mittagessen gesammelt und auf ihre Gehalte an Jodid und NaCl analysiert. Bei durchschnittlich ähnlichem Kochsalzgehalt enthielt das Essen in Mensa A im Mittel 6,1 µg I/100 g ww (8,5 µg I/g NaCl) mehr Jod als in Mensa B. Die Gesamtjodaufnahme mit einem durchschnittlichen Mittagessen in Mensa A betrug demnach 56,5±24,1 µg (Mensa B: 17,0±9,9 µg). Dem Einsatz von jodiertem Speisesalz in der Gemeinschaftsverpflegung scheint somit eine wichtigere Rolle auf dem Weg zu einer ausreichenden Jodaufnahme zuzukommen als bisher angenommen wurde.
    Notes: Summary In each of two university canteens differing in the use (canteen A) or non-use (canteen B) of iodized salt for food preparation, 15 mostly equal lunch meals were collected for iodide and NaCl analysis. With similar NaCl content, the meals of canteen A contained on average 6.1 µg I/100 g ww (8.5 µg I/g NaCl) more I than the meals of canteen B. Total I intake by consumption of an average meal of canteen A was estimated as 56.5±24.1 µg (canteen B: 17.0±9.9 µg). Consequently, the use of iodized salt in central catering seems to play a more important role in a sufficient I intake than assumed so far.
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  • 66
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    European journal of nutrition 34 (1995), S. 284-292 
    ISSN: 1436-6215
    Keywords: Human placenta ; brush border membrane ; alanine transport ; group specific reagents ; SH-groups ; Alanintransport ; menschliche Plazenta ; Kinetik ; gruppenspezifische Reagentien ; SH-Gruppen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Transportsysteme in der apikalen Zellmembran der Syncytiothrophoblasten der Plazenta sind für den Nährstoff-transport aus dem mütterlichen Kreislauf in den fetalen Stoffwechsel von elementarer Bedeutung für Wachstum und Entwicklung des Fötus. Die Carriersysteme für Aminosäuren limitieren dabei die Versorgung des Fötus mit essentiellen und nicht essentiellen Aminosäuren. An isolierten Bürstensaummembranvesikeln (BBMV) reifer menschlicher Placenta haben wir die Aufnahme von neutralen Aminosäuren am Beispiel von Alanin charakterisiert. Darüber hinaus wurden durch den Einsatz gruppenspezifischer Reagentien wichtige Aminosäureseitengruppen der entsprechenden Transportproteine identifiziert. Die Alaninaufnahme in die BBMV wird durch zwei sättigbare Carriersysteme mit unterschiedlichen Eigenschaften vermittelt. Neben einem elektrogenen Na+-abhängigen System, das auch Gln, meAIB und Met transportiert, existiert ein Na+-unabhängiges System, das kein meAIB, dafür aber zusätzlich Leu und Tyr transportiert. Beide Transportsysteme haben gleiche Affinitätskonstanten (Km-Werte) für Alanin (0,45±0,06 mmol/l). Das Na+-abhängige System transportiert Alanin mit einer 1:1 Stöchiometrie mit Na+-Ionen und weist eine 3fach höhere maximale Transportgeschwindigkeit auf. Durch Einsatz gruppenspezifischer Reagentien wurden freie SH-Gruppen in den beiden Carriern identifiziert, die für die Funktion von entscheidender Bedeutung sind. Durch Oxidation und Rückreduktion der SH-Gruppen konnte die Transportleistung der Carrier reversibel verändert werden. Da die modifizierenden Reagentien die SH-Gruppen auch in Gegenwart der Substrate blockierten, ist zu vermuten, daß die wichtigen SH-Gruppen nicht in der Substratbindungsstelle der Transportproteine liegen.
    Notes: Summary We have determined the kinetic characteristics of alanine transport into brush border membrane vesicles (BBMV) of human full term placenta and identified functional groups of the carrier proteins that are important for transport function. Alanine influx into BBMV was found to be mediated by two transport systems with different kinetic features and distinct substrate specificities. An uphill operating electrogenic Na+-dependent contransport system could be kinetically separated from a Na+-independent facilitated diffusion system. The Na+-dependent transporter mediates Na+-alanine cotransport with a 1:1 flux coupling ratio (Hill coefficient 1.13±0.12) and a Km for alanine of 0.45±0.06 mmol/l. Halfmaximal stimulation of Na+-dependent alanine influx was observed at a Na+ concentration (NaCl) of 51.4±1.3 mmol/l. A variety of group specific reagents were used to identify functional groups in the transport proteins. Only compounds reacting with SH-residues (NEM, DTNB, PCMBS) or NH2-groups (PITC) were found to affect Na+ dependent and Na+ independent alanine transport. The EC50 value for inhibition of alanine influx by PCMBS was 450±48 µmol/l. Chemical modifications of SH-groups by PCMBS caused a significant reduction (p〈0.005) in the Vmax for Na+-dependent alanine influx from 0.57±0.06 to 0.16±0.05 nmol·mg protein−1·10s−1 without affecting significantly the Km value. Inhibition by PCMBS was reversed by treatment of BBMV with DTT. When the substrate binding site of the transporter was protected by alanine or leucine, PCMBS still blocked transport function, indicating that the cruical SH groups are not located within the substrate binding site of the transport proteins.
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  • 67
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    Keywords: Sardinen ; Diäten mit Cholesterol bereichert ; Cholesterolspiegel ; Serumtriglyceride ; Olivenöl ; Sonnenblumenöl ; Fried sardines ; cholesterol-enriched diets ; serum cholesterol ; serum triglycerides ; olive oil ; sunflower oil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The effect of diets containing olive-oil-fried sardines (diet 1) or sunflower-oil-fried sardines (diet 3) upon the serum cholesterolraise induced by dietary cholesterol was studied after a 4-week experiment in growing Wistar rats. Results of diet 1 were compared to those obtained in diets containing casein plus olive oil (diet 2), whereas results of diet 3 were compared to those obtained with casein plus sunflower oil (diet 4). All diets contained cholesterol and bovine bile as a cholesterol-raising agent. The hypercholesterolemic effect of dietary cholesterol in fried-sardine groups (a total cholesterol (TC) increase of 0.9 mmol/L (p〈0.05 and 0.4 mmol/L (not significant) in groups 1 and 3, respectively) was markedly lower than in groups 2 and 4 (a TC increase of 13.9 mmol/L (p〈0.01) and 18.2 mmol/L (p〈0.01), respectively). Serum triglyceride levels decreased in fried-sardine diets (p〈0.05) while they increased in casein diets (p〈0.05). HDL-cholesterol levels appear lower in diet 1 than in diet 2 (p〈0.05), but similar in diets 3 and 4. However, HDL-fraction carries in diets 1, 2, 3 and 4, 13 %, 4 %, 53 % and 5 % of TC, respectively. Results showed that fried-sardine diets exert a powerful check effect on the cholesterol-raising effect induced by dietary cholesterol.
    Notes: Zusammenfassung In Versuchen von 4 Wochen Dauer wurde der Einfluß cholesterolangereicherter Diäten, die in Olivenöl (Diät 1) oder in Sonnenblumenöl (Diät 3) gebratene Sardinen enthielten, auf die Erhöhung des Cholesterolspiegels bei wachsenden Wistar Ratten untersucht. Die Ergebnisse von Diät 1 wurden mit denen von Diät 2 (Kasein plus Olivenöl) und die Resultate von Diät 3 mit denen von Diät 4 (Kasein plus Sonnenblumenöl) verglichen. Alle Diäten enthielten Cholesterol und Rindergalle als cholesterolerhöhende Agentien. Der hypercholesterolämische Effekt war in den Diäten mit den gebratenen Sardinen (eine Erhöhung des Cholesterolspiegels (TC) von je 0.9 mmol/L (p〈0.05) und 0.4 mmol/L (nicht signifikant) in den Gruppen 1 und 3) auffallend kleiner als in den Kontrollgruppen 2 und 4 mit Kasein (eine Erhöhung des TC von je 13.9 mmol/L (p〈0.01) und 18.2 mmol/L (p〈0.05)). Die Serumtriglyceride fielen bei Aufnahme der Sardinen (p〈0.05) und stiegen bei Aufnahme der Kasein-Diäten (p〈0.05). Das HDL-Cholesterolgehalt war niedriger mit Diät 1 als mit Diät 2 (p〈0.05) aber ähnlich bei den Diäten 3 und 4. Die HDL-Fraktion betrug in den Diäten 1, 2, 3 und 4 je 13 %, 4 %, 53 % und 5 % des TC. Diese Ergebnisse zeigen, daß Diäten mit gebratenen Sardinen eine große Hemmwirkung auf den cholesterolerhöhenden Effekt des Cholesterols haben.
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    European journal of nutrition 34 (1995), S. 277-283 
    ISSN: 1436-6215
    Keywords: Selen ; Glutathion-Peroxidase ; Schilddrüsenhormone ; Thyroxin ; Triiodthyronin ; Typ-I-Deiodase ; Selenium ; glutathione peroxidase ; thyroid hormones ; thyroxine ; triiodothyronine ; type-I-deiodinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary In an experiment with 72 male weanling Sprague Dawley rats the effect of varying selenium intake on parameters of thyroid hormone metabolism was investigated. The animals were divided into 6 groups. One of the groups was fed a semi-synthetic diet based on casein which was poor in selenium (38 µg/kg). The other groups were fed the same diet supplemented with Na2SO3·5H2O to achieve a selenium concentration of 50, 100, 300, 600 and 3 000 µg/kg. The experiment lasted 40 days. Different selenium intake had no effect on food intake, weight gain, hematological and selected clinical-chemical parameters. Determination of glutathione peroxidase activity and selenium concentration of serum showed a selenium deficiency in animals fed the diet not supplemented with selenium. Serum T3 concentration and hepatic type-I-deiodinase activity were decreased in the group without selenium supplementation in contrast to the groups fed diets adequate in selenium (100, 300 µg/kg). A diet supplementation of 50 µg/kg already increased hepatic type-I-deiodinase activity to levels of the groups fed diets adequate in selenium. In groups supplemented with 600 and 3 000 µg/kg diet, serum T3 concentration was reduced by half of groups fed diets adequate in selenium. Supplementation with 3 000 µg Se/kg lowered the type-I-deiodinase activity in contrast to groups fed diets adequate in selenium, but not significantly. Serum concentrations of T4 and fT4 were not changed by various selenium intake. The results of this investigation show an alteration in thyroid hormone metabolism at low selenium intake as well as at high selenium intake.
    Notes: Zusammenfassung Die Auswirkungen einer unterschiedlichen Selenversorgung auf Parameter des Stoffwechsels der Schilddrüsenhormone sollten in einem Versuch mit 72 männlichen wachsenden Sprague Dawley Ratten untersucht werden. Die Tiere wurden in 6 Gruppen eingeteilt, wovon eine Gruppe eine selenarme halbsynthetische Diät auf Caseinbasis mit einem Se-Gehalt von 38 µg/kg erhielt. Die übrigen Gruppen erhielten die selbe Diät, die durch Zulage von Na2SO3·5H2O auf Selengehalte von 50, 100, 300, 600 und 3 000 µg/kg gebracht wurde. Die Versuchsdauer betrug 40 Tage. Die unterschiedliche Zufuhr von Selen hatte keinen Einfluß auf Futteraufnahme, Entwicklung der Lebendmasse, hämatologische und ausgewählte klinisch-chemische Parameter. Ein Selenmangel bei der Gruppe, die die nicht supplementierte Basisdiät erhalten hatte, konnte anhand der Aktivität der Glutathion-Peroxidase und der Selenkonzentration im Serum diagnostiziert werden. Beide Parameter stiegen ab einer Se-Zulage von 300 µg/kg noch an, allerdings geringfügig. Die Konzentration von T3 im Serum und die Aktivität der Typ-I-Deiodase in der Leber der Gruppe ohne Selenzulage war im Vergleich zu den bedarfsgerecht (100, 300 µg/kg) versorgten Gruppen vermindert. Bereits eine Selenzulage von 50 µg/kg Diät konnte die Aktivität der Typ-I-Deiodase auf die Werte der bedarfsgerecht versorgten Gruppen mit 100 und 300 µg Selenzulage anheben. Bei den Gruppen mit 600 und 3 000 µg/kg Diät Selenzulage war die Konzentration von T3 im Serum im Vergleich zu den bedarfsgerecht versorgten Gruppen auf etwa die Hälfte reduziert. Durch die Selenzulage von 3 000 µg/kg Diät war die Aktivität der Typ-I-Deiodase gegenüber den bedarfsgerecht versorgten Gruppen vermindert, die Verminderung war jedoch nicht statistisch signifikant. Die Konzentrationen von T4 und fT4 waren durch die unterschiedliche Selenzufuhr kaum verändert. Die Untersuchung zeigt insgesamt, daß sowohl unzureichende als auch über den Bedarf hinausgehende Selenzufuhr zu Veränderungen im Stoffwechsel der Schilddrüsenhormone führt.
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    European journal of nutrition 34 (1995), S. 1-1 
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    Source: Springer Online Journal Archives 1860-2000
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    European journal of nutrition 34 (1995), S. 30-31 
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    Source: Springer Online Journal Archives 1860-2000
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    European journal of nutrition 34 (1995), S. 113-117 
    ISSN: 1436-6215
    Keywords: Blei ; Cadmium ; Quecksilber ; Gewürze ; Gewürzzubereitungen ; Wurstwaren ; Lead ; cadmium ; mercury ; spices ; condiments ; meat products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The lead and cadmium contents of 50 spices and 19 condiments were investigated by means of flameless atomic absorption spectrophotometry. Mercury contents were determined by cold vapor atomic absorption method including amalgamation. The mean concentrations of lead, cadmium, and mercury were 0.470 mg/kg, 0.080 mg/kg, and 0.005 mg/kg, respectively. By using the detected levels of these three heavy metals in model calculations only a small carry-over of lead, cadmium, and mercury in meat products by spices and condiments can be assumed.
    Notes: Zusammenfassung 50 Gewürze und 19 Gewürzzubereitungen wurden mittels flammenloser Atomabsorptionsspektrometrie auf ihren Blei- und Cadmiumgehalt sowie mittels Kaltdampftechnik und nachfolgender Amalgamierung auf ihren Quecksilbergehalt untersucht. Im Mittel wurden hierbei 0,470 mg Blei, 0,080 mg Cadmium und 0,005 mg Quecksilber pro kg Würzmittel gefunden. Anhand von Modellrechnungen wurde ein nur geringer Blei-, Cadmium- und Quecksilbereintrag über Würzmittel in die Wurstsorten Fleischwurst, Leberwurst und Mettwurst aufgezeigt.
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    European journal of nutrition 34 (1995), S. 137-142 
    ISSN: 1436-6215
    Keywords: Taurine ; plasma ; whole blood ; depletion ; supplementation ; Taurin ; Plasma ; Gesamtblut ; Taurinmangel ; Supplementation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Die vorliegende Studie untersuchte die Beziehung zwischen der Taurinkonzentration in Plasma und Gesamtblut unter normalen physiologischen Bedingungen bei Menschen und bei Katzen sowie nach oraler Taurinsupplementierung beim Menschen und nach taurinfreier Fütterung bei Katzen. Beim Menschen betrug die durchschnittliche Taurinkonzentration im Plasma 44±8 µmol/L und im Gesamtblut 222±35 µmol/L. Unter diesen „physiologisch normalen“ Bedingungen bestand zwischen der Taurinkonzentration in Plasma und Gesamtblut keine Korrelation (r=0.092). Die Plasmataurinkonzentration stieg nach oraler Taurinsupplementierung beim Menschen rasch an bzw. fiel schnell nach taurinfreier Ernährung bei Katzen ab. Die Taurinkonzentration im Gesamtblut war dagegen mehr inert und änderte sich erst nach anhaltender Taurinzufuhr beim Menschen bzw. nach andauerndem Taurinmangel bei Katzen.
    Notes: Summary In the present study the relationship between plasma and whole blood taurine was examined under normal physiological circumstances in humans and cats. In addition, the effect of taurine supplementation on plasma and whole blood taurine was evaluated in humans and the depletion of taurine pools after a taurine-deprived diet was studied in cats. The normal plasma taurine concentration in humans was 44±8 µmol/L and the whole blood taurine concentration was 227±35 µmol/L. Under normal physiological conditions plasma and whole blood taurine were not correlated (r=0.092). Plasma taurine responded rapidly to dietary supplementation in humans or the taurine depletion in cats. In contrast, the whole blood taurine pool was more inert and varied only under extremes of depletion (cats) or sustained taurine supplementation.
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  • 73
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    Keywords: Strontium ; oraler Strontium-Test ; Calcium ; Absorption ; gesunde Probanden ; Strontium ; oral strontium test ; calcium ; absorption ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Intestinal strontium absorption has been discussed recently as an indirect measure for calcium uptake. Prerequisite for the clinical use of an oral strontium test is the availability of a reliable procedure including controlled strontium supply, sample pretreatment and analysis as well as the assessment of normal values. In the present study, a group of young females (n=33; 24.0 ± 2.7 y; BMI 21.5 ± 1.9) received an oral dose of 2.27 mmol strontium in a standardized breakfast that contained 0.625 mmol calcium. Before and 220 min after the bolus serum strontium concentrations were determined by means of atomic absorption spectrophotometry (coefficient of variation: within day 4.8 %, n=10; day-to-day 9.5 %, n=8). The error of the method was 2.7 %. Calculation of the fractional strontium absorption rate considered the respective distribution volume (extracellular fluid; either estimated using body weight or determined by means of bioimpedance analysis [BIA]). Average absorption rates were 13.3 ± 3.1 % and, considering BIA measurement 13.6 ± 2.6 %, respectively. Smoking, exercise and, use of oral contraceptives showed no effects. Our oral strontium test is characterized by excellent reliability, easy handling and low costs and, thus, is suitable for routine use.
    Notes: Zusammenfassung Die Erfassung der Strontiumabsorption wird heute als indirektes Verfahren zur Beurteilung der intestinalen Calciumabsorption diskutiert. Voraussetzung für die klinische Anwendung ist ein vertrauenswürdiges Testverfahren inclusive kontrollierter Strontiumgabe, Probenaufarbeitung und -analyse sowie die Erfassung von Normalwerten. Für unsere Studien wurde ein Kollektiv junger Frauen (n=33, 24,0 ± 2,7 Jahre; BMI 21,5 ± 1,9) herangezogen. Die Probandinnen erhielten eine Bolusgabe von 2,27 mmol Strontium zusammen mit einem Standardfrühstück (ca. 0,625 mmol Calcium). Vor und 220 min nach der Bolusgabe erfolgte die Bestimmung des Serum-Strontiumgehaltes mittels Atomabsorptionsspektrometrie. Der Variationskoeffizient der Methode lag innerhalb eines Tages bei 4,8 % (n=10) und von Tag zu Tag 9,5 % (n=8). Der Fehler der Methode betrug 2,7 %. Die Berechnung der fraktionellen Strontiumabsorptionsrate erfolgte unter Berücksichtigung des entsprechenden Verteilungsraumes (Extrazellulärflüssigkeit; Schätzverfahren über Körpergewicht bzw. Bioimpedanz-Analyse [BIA]). Die Strontiumabsorptionsrate lag im Mittel bei 13,3 ± 3,1 %, unter Berücksichtigung der BIA-Werte bei 13,6 ± 2,6 %. Rauchen, sportliche Aktivität bzw. Einnahme oraler Kontrazeptiva zeigten keinen Einfluß. Das hier vorgestellte Testverfahren ist aufgrund seiner hohen Vertrauenswürdigkeit und relativ einfacher Handhabung für Routine-untersuchungen geeignet.
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    European journal of nutrition 34 (1995), S. 214-219 
    ISSN: 1436-6215
    Keywords: Amylin ; food intake ; vagotomy ; circadian effect ; rat ; Amylin ; Futteraufnahme ; Vagotomie ; zirkadiane Effekte ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Das aus dem Pankreas stammende Peptid Amylin (1 µg/kg) reduzierte nach intraperitonealer (IP) Injektion die kumulative Futteraufnahme bei Ratten, denen vor der Injektion das Futter für 24 h entzogen worden war bzw. bei Ratten, denen Futter ad lib. zur Verfügung stand, für bis zu 4 h. Der Effekt trat zu verschiedenen Zeitpunkten des Tag/Nacht-Zyklus (Beginn der Dunkelphase, Mitte der Dunkelphase, Beginn der Hellphase) auf. Der verzehrsreduzierende Effekt von IP verabreichtem Amylin wurde zu keinem dieser Zeitpunkte durch subdiaphragmatische Vagotomie aufgehoben. Vagotomie führte eher zu einer Verstärkung des verzehrsreduzierenden Effekts von Amylin, und zwar nach einem 24stündigen Futterentzug bei Injektion zu Beginn der Hellphase oder in der Mitte der Dunkelphase. Im Unterschied zu früheren Untersuchungen mit älteren Ratten konnte ein verzehrsreduzierender Effekt von Amylin auch bei Ratten beobachtet werden, denen vor der Injektion das Futter nicht entzogen worden war. In Ergänzung früherer Befunde zeigen also die Ergebnisse, daß der verzehrsreduzierende Effekt von IP verabreichtem Amylin zu verschiedenen Tageszeiten ausgelöst und durch subdiaphragmatische Vagotomie nicht aufgehoben werden kann.
    Notes: Summary The pancreatic peptide amylin (1 µg/kg) injected intraperitoneally reduced cumulative food intake for up to 4 h in food-deprived (24 h) and non-deprived rats at various times of the day, i.e., at dark onset, in the middle of the dark phase, and at light onset. At none of these times did subdiaphragmatic vagotomy abolish the anorectic effect of amylin. Rather, vagotomy enhanced, by unknown mechanisms, amylin's anorectic effect in food-deprived rats at light onset and in the middle of the dark phase. In contrast to previous studies with older rats, amylin's anorectic effect was also observed when injected into nondeprived rats. The findings of the present study extend previous reports in that amylin's anorectic effect, not being abolished by abdominal vagotomy after intraperitoneal injection, can be elicited at different times of the day.
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    European journal of nutrition 34 (1995), S. 236-239 
    ISSN: 1436-6215
    Keywords: Verpflegungsplanung ; Krankenhausverpflegung ; Diabetesdiät ; Speisenauswahl ; wissensbasiertes System ; Menu planning ; hospital menu ; diabetes diet ; food selection ; knowledge-based system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Menu planning in hospitals is a complex decision problem. Patients expect the menu plan to be healthful and in accordance with their nutritional habits. Furthermore, the menu plan must conform to capacity limits of the kitchen. In this paper we present an approach to computerized food selection and menu composition. The model is based on nutritional knowledge, which is represented in the computer and used for problem solving.
    Notes: Zusammenfassung Die Planung einer Krankenhausverpflegung stellt sich als komplexes Entscheidungsproblem dar. Die Verpflegung soll der Gesundheit der Patienten zuträglich sein, deren Ernährungsgewohnheiten entsprechen und im Rahmen der Küchenkapazität hergestellt werden können. In der vorliegenden Arbeit wird am Beispiel der Diätverpflegung für Diabetiker ein computerunterstütztes Modell vorgestellt, das den Entscheidungsträgern im Krankenhaus Hilfestellung bei der Auswahl der Speisen und deren Zusammenstellung zu Menüs bietet. Die Planung erfolgt auf der Basis ernährungs- und haushaltswissenschaftlichen Fachwissens, das im Computer abgebildet und zur Problemlösung genutzt wird.
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    European journal of nutrition 34 (1995), S. 32-33 
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    Source: Springer Online Journal Archives 1860-2000
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    European journal of nutrition 34 (1995), S. 34-34 
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    Source: Springer Online Journal Archives 1860-2000
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    European journal of nutrition 34 (1995), S. 95-112 
    ISSN: 1436-6215
    Keywords: Ernährungsgeschichte ; Nahrungsgewohnheiten ; Ernährungspolitk ; Lebensmittelverfälschungen ; Lebensmittelrecht ; Food history ; food habits ; food policy ; food adulterations ; food legislation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary During the last two decades, there has been an increasing movement in Germany to protect the natural environment from dangerous substances. This has renewed a growing common interest in government food control. This contribution ask the question of how this food legislation as a part of the general food and health policy in Germany came into being, and which promoting as well as inhibiting determinants in this scope could be observed. These statements are based partly on results of a project of the German National Research Council (Deutsche Forschungsgemeinschaft) in which the author investigates the change of food habits under the impact of industrialization and urbanization since the last century in a larger historical perspective and in a quantitative and qualitative manner with the help of current sources.
    Notes: Zusammenfassung Die in den letzten beiden Jahrzehnten in Deutschland angewachsene Bewegung zum Schutz der natürlichen Ressourcen und der verstärkten Reinerhaltung der Umwelt vor gefährlichen Schadstoffen hat auch die staatliche Lebensmittelüberwachung wieder stärker in den Brennpunkt des öffentlichen Interesses gerückt. Der Beitrag geht der bisher nur unzureichend behandelten Frage nach, wie diese gesetzliche Lebensmittelkontrolle als Bestandteil staatlicher Ernährungs- und Gesundheitspolitik in Deutschland entstanden ist und welche beschleunigenden und hemmenden Determinanten es dabei gegeben hat. Die Ausführungen basieren auf Teilergebnissen eines neuen Projekts der Deutschen Forschungsgemeinschaft, mit dem der Verfasser den Wandel der Nahrungsgewohnheiten unter dem Einfluß der Industrialisierung und Urbanisierung seit dem vorigen Jahrhundert erstmals im größeren historischen Zusammenhang anhand der überlieferten zeitgenössischen Quellen quantitativ wie qualitativ analysiert.
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    European journal of nutrition 34 (1995), S. 151-159 
    ISSN: 1436-6215
    Keywords: Fischöl ; Hyperlipoproteinämie ; Omega-3-Fettsäuren ; Triglyzeride ; Vitamin E ; Fish oil ; hyperlipoproteinemia ; omega-3 fatty acids ; triglycerides ; vitamin E
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary In 56 patients with HLP (40 with hypertriglyceridemia and mixed HLP respectively and 16 with hypercholesterolemia), changes in the lipid state and in the parameters of the antioxidative potential before and after a 4-week olive-oil phase, and after 8-, 20-and 32-week intakes of salmon-oil capsules were determined. The treatment with salmon-oil led to a decrease of triglycerides in patients with hypertriglyceridemia and mixed HLP respectively, on the other hand, it led to an increase of cholesterol in hypercholesterolemia. The increase of malondialdehyde as measure of lipid peroxidation in both patient groups underlines the necessity of a substitution of antioxidants. Further investigations are necessary before wide use of fishoil capsules can be recommended, expecially to avoid side-effects.
    Notes: Zusammenfassung Bei 56 Patienten mit HLP (40 Hypertriglyzeridämie bzw. mixed HLP und 16 mit Hypercholesterinämie) wurden Veränderungen im Lipidstatus und bei Parametern des antioxidativen Potentials vor und nach einer vierwöchigen Olivenölphase und nach 8, 20 und 32 Wochen Einnahme von Lachsölkapseln ermittelt. Die Behandlung mit Lachsöl führte bei Patienten mit Hypertriglyzeridämie/mixed HLP zu einer Senkung der Triglyzeride, dagegen bei Hypercholesterinämie zu einer Zunahme des Cholesterins. Die Erhöhung des Malondialdehyds als Maß für die Lipidperoxidation in beiden Patientengruppen unterstreicht die Notwendigkeit einer Substitution mit Antioxidantien. Vor einem breiten Einsatz von Fischölkapseln sind allerdings weitere Untersuchungen, nicht zuletzt zur Verringerung der Nebenwirkungen, erforderlich.
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    European journal of nutrition 34 (1995), S. 143-150 
    ISSN: 1436-6215
    Keywords: Fischöl ; Olivenöl ; Sauen ; Energiebilanz ; Thermogenese ; Gaswechsel ; Fish oil ; olive oil ; sows ; energy balance ; thermogenesis ; gaseous exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary An animal model experiment was conducted with nine adult sows to study the effect of olive oil and fish oil (40 % polyunsaturated fatty acids) on thermogenesis compared to wheat starch as control. The treatments were given to each animal according to a latin square design. The basal diet (20 g DM/kg W0.75) was mainly based on barley and soybean meal, and matched 60 % of the ME requirements with all the other nutrients meeting maintenance requirements. The isoenergetic supplements amounted to 176 kJ gross energy per kg W0.75 and day. During each experimental period a complete energy balance was recorded for each animal using indirect calorimetry technique (RQ-method) as well as the carbonnitrogen-balance technique. The treatments did not influence the digestibility of the rations. Digestibility of energy and of carbon averaged 83.4 % and 83.3 %, respectively. All three supplements were nearly completly digested as calculated by the difference method. Fish oil increased urine energy and decreased CH4 production, the shifts, however, were in absolute terms very small. The mean O2 consumption was 1 002 l/d showing no significant treatment effects. CO2 production was lowered with olive oil by 10 %, and with fish oil by 13 % compared to the starch diet. The daily heat production was 20.95, 20.72, and 20.04 MJ when starch, olive oil or fish oil was given. Corrected for equal energy retention the difference of thermogenesis between olive oil and starch was −0.4 MJ/d, and between fish oil and starch −1.2 MJ/d. These differences corresponded to a relation of starch:olive oil:fish oil=1:0.95:0.86. The relation between starch and olive oil reflected exactly the theoretical expectation, calculated from the ATP regeneration by oxidation of both nutrients. When fish oil was added, the daily heat production was lower than theoretically calculated, which might be interpreted as an effect on the metabolic rate in general rather than especially on the efficiency of ATP formation from fish oil oxidation. In any case, there was no hint of a facultative thermogenesis induced by the oils.
    Notes: Zusammenfassung Mit Hilfe der kalorimetrischen Bilanztechnik wurde an 9 Sauen nach dem Schema eines lateinischen Quadrates die Wirkung von Olivenöl und Fischöl im Vergleich zu Weizenquellstärke auf die Thermogenese im Erhaltungsstoffwechsel gemessen. Die zu prüfenden Nährstoffe wurden einer Basisration (20 g TM/kg W0,75) zugelegt, die auf 60 % des energetischen Erhaltungsbedarfs an umsetzbarer Energie ausgerichtet war. Die isoenergetischen Zulagen betrugen jeweils 176 kJ Bruttoenergie/kg W0,75. Von allen Tieren wurde in jeder Stoffwechselperiode eine vollständige Energiebilanz erfaßt. Die Versuchsbehandlung hatte keinen Einfluß auf die Verdaulichkeit der Rationen. Die mittleren VQ-Werte der Gesamtration betrugen 83,4 % für Energie und 83,3 % für Kohlenstoff. Die Energieverdaulichkeit der Zulagen betrug in allen Fällen um 100 %. Fischöl erhöhte signifikant die Harnenergie und verminderte die CH4-Bildung im Vergleich zu den beiden anderen Rationen. Allerdings waren diese Veränderungen absolut gesehen nur minimal. Der Sauerstoffverbrauch betrug im Mittel 1002 l/d und zeigte keine Behandlungsdifferenzen. Die CO2-Abgabe war bei Verabreichung von Olivenöl um 10 % und bei Fischöl um 13 % signifikant niedriger. Die tägliche Wärmebildung betrug 20,95, 20,72 bzw. 20,04 MJ bei Fütterung der Rationen mit Stärke, Olivenöl bzw. Fischöl. Auf der Basis gleicher Energieretention verglichen, betrug der Unterschied in der Thermogenese zwischen Olivenöldiät und Stärkediät −0,4 MJ/d, der zwischen Fischöldiät und Stärkediät −1,2 MJ/d. Dies entsprach einer Relation von Stärke:Olivenöl:Fischöl=1:0,95:0,86. Das Verhältnis zwischen Stärke:Olivenöl widerspiegelte genau die theoretische Erwartung aufgrund der ATP-Regenerierung durch Oxidation dieser beiden Nährstoffe. Fischöl (ca. 40 % mehrfach ungesättigte Fettsäuren) wies eine tendenziell niedrigere Thermogenese als theoretisch erwartet auf, was möglicherweise auf einer entsprechenden Absenkung des Erhaltungsumsatzes beruhte. Die Ergebnisse zeigen, daß die verwendeten Öle keine fakultative Thermogenese induzierten.
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  • 81
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    European journal of nutrition 34 (1995), S. 183-189 
    ISSN: 1436-6215
    Keywords: Validation ; 24-hour recall questionnaire ; dietary survey ; energy intake ; nutrient intake ; food intake ; Validierung ; 24-hour-recall-Fragebogen ; Ernährungserhebung ; Energieaufnahme ; Nährstoffaufnahme ; Nahrungsaufnahme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Ziel der Arbeit war, die relative Validität eines selbstgeführten 24-hour-recall-Fragebogens zu untersuchen, der in einer Ernährungserhebung mit 3 653 weiblichen und männlichen Erhebungsteilnehmern im Alter ab 7 Jahren eingesetzt wurde. Die Validierung wurde an einer Gruppe von 41 Männern durchgeführt. Ein 3-Tage-Protokoll diente als Referenzmethode. Der Vergleich des 24-hour-recall-Fragebogens mit dem 3-Tage-Protokoll erbrachte gute Übereinstimmung. Mittels des Wilcoxon matched-pairs ranked signs test (p〈0.05) konnten nur für die absoluten Energie- und Kohlenhydrataufnahmen sowie für die Protein-Nährstoffdichte signifikante Unterschiede nachgewiesen werden. Die prozentuale Verteilung der Energie auf die Hauptnährstoffe und Alkohol differierte um maximal 2,4 %. Der mediane prozentuale Unterschied in der absoluten Nährstoffaufnahme und der Nährstoffdichte lag zwischen −9 und 22 %. Die tägliche Nahrungsaufnahme war nur für 3 von 10 Lebensmittelgruppen signifikant verschieden. Die Spearman rank Korrelationskoeffizienten betrugen für alle Nährstoffdichten mehr als 0,35. Die höchsten Korrelationskoeffizienten um 0,60 wurden für die Alkoholund Nahrungsfaseraufnahme beobachtet. Die Ergebnisse zeigen, daß der 24-hour-recall-Fragebogen eine valide Methode zur Schätzung der medianen und mittleren Nahrungs-und Nährstoffaufnahme von großen Gruppen ist.
    Notes: Summary This study investigated the relative validity of a self-administered 24-h recall questionnaire in a dietary survey on 3 653 men and women 7 years of age and older. The validation was carried out in a group of 41 men. An estimated dietary record kept over 3 days served as reference method. Comparison of the questionnaire and the estimated 3-day record showed good agreement. The Wilcoxon matchedpairs ranked signs test (p〈0.05) demonstrated that the only differences were the crude energy and carbohydrate intake and the estimated nutrient density of protein. The estimated proportion of calories from carbohydrate, fat, protein, and alcohol differed by no more than 2.4 %. The median percentage differences in crude nutrient intakes and nutrient densities between the two assessment techniques ranged from −9 % to 22 %. The daily food intake differed significantly in only three of ten food groups. Spearman's correlation coefficients were higher than 0,35 for all density measurements. The highest correlation coefficients of about 0.60 were observed for alcohol and dietary fiber intake. It is concluded that the self-administered 24-hour recall questionnaire is a valid method for estimating the median and mean dietary intake of large groups of subjects.
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  • 82
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    European journal of nutrition 34 (1995), S. 198-205 
    ISSN: 1436-6215
    Keywords: Forelle ; Tocopherol ; Phyllochinon ; Antioxidans ; Lipidstabilität ; Trout ; tocopherol ; phylloquinone ; antioxidant ; storage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Rainbow trouts were fed a complete diet with 12 mg vitamin K3 and supplemented with 20, 200 or 2 000 mg all-rac-α-tocopheryl-acetate/kg for 18 weeks. The ratio of the vitamin E-supplementation was 1 : 10 : 100. Fillets were minced and stored at −18 °C. Concentrations of α-tocopherol and phylloquinone and parameters of lipid peroxidation were measured after 4, 6, and 8 months of storage. The effects of α-tocopherol incorporated into fillets on storage stability were assessed by measuring free fatty acids, peroxides, malondialdehyde and lipofuscin. Mean α-tocopherol-concentrations in fillets were 1.4, 2.7 and 16.3 mg/100 g, respectively representing ratios of 1 : 2 : 12. The increase in α-tocopherol concentration resulted in a significant improvement of storage stability. The phylloquinone concentration in fillet was reduced in treatments with ≥200 mg vitamin E/kg; however, this did not affect the prothrombin time. No peroxides were detectable at any time. The concentrations of malondialdehyde significantly decreased with increasing supplementation of vitamin E. Lipofuscin concentrations were higher with low than with high vitamin E supplementation. The dose-related inhibition of lipid peroxidation became apparent in decreased concentrations of the free fatty acids in the crude fat. These results confirm the effectiveness of α-tocopherol as antioxidant in fish flesh. In this study the incorporation of α-tocopherol from dietary supplementation improved the long-term storage quality of trout fillets due to the effective inhibition of the lipid peroxidation. A measurable improvement of the storage stability was achieved with a supplementation of 200 mg vitamin E/kg feed.
    Notes: Zusammenfassung Filet von Forellen, die 18 Wochen lang ein Futter mit 12 mg Menadion/kg und mit drei im Konzentrationsverhältnis von 1 : 10 : 100 gestaffelten Dosierungen von all-rac-α-Tocopherylacetat (20, 200 und 2 000 mg/kg) erhalten hatten, wurde homogenisiert und bei −18 °C gelagert. Nach Lagerung über 4, 6 und 8 Monaten wurden die Konzentrationen an α-Tocopherol und Phyllochinon sowie von freien Fettsäuren, Peroxiden, Malondialdehyd und Lipofuszin als Parameter der Lipidperoxidation analysiert. Die mittleren α-Tocopherolgehalte betrugen 1,4; 2,7 und 16,3 mg/100 g Filet, entsprechend einem Konzentrationsverhältnis von etwa 1 : 2 : 12. Der dosisabhängige Anstieg bewirkte eine deutliche Verbesserung der Lagerstabilität. Die hohen Dosen an Vitamin E führten zu abnehmenden Gehalten an Phyllochinon im Fischmuskel, die ohne Einfluß auf die Prothrombinzeit waren. Die dosisabhängige Hemmung der enzymatisch katalysierten Fettoxidation spiegelte sich in abfallenden Gehalten an freien Fettsäuren im Rohfett wider. Peroxide waren an keinem Untersuchungstermin nachweisbar. Die Gehalte an Malondialdehyd sanken mit zunehmender Supplementierung von Vitamin E signifikant ab. Derselbe Einfluß zeigte sich bei Lipofuszin. Die Anreicherung der Filets mit α-Tocopherol nach Supplementierung des Futters begünstigte eine längerfristige Qualität bei Gefrierlagerung infolge einer effektiven Hemmung der Lipidperoxidation. Bereits mit der Dosierung von 200 mg α-Tocopherylacetat/kg Futter konnte im Vergleich zur Dosierung von 20 mg/kg eine meßbare Verbesserung der Lagerstabilität erzielt werden.
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  • 83
    ISSN: 1436-6215
    Keywords: ω-3 Fettsäuren ; Kolonkarzinom ; Diät ; Fett ; Lipoproteine ; ω-3 fatty acids ; colonic neoplasms ; diet ; fat ; lipoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Several studies indicated a protective effect of fish oil on colon carcionogenesis which might be due to alterations in prostaglandin E2 synthesis of the colonic mucosa. Additional effects on fecal bile acid excretion may also play a role since especially secondary bile acids are known to act as promotors in colon cancer development. In the present study possible influences on bile acid excretion were investigated in 12 healthy volunteers whose daily diet was supplemented for 4 weeks with 11 g of fish oil (FO) and corn oil (CO) per day, respectively. Fecal bile acids were analyzed by gas-liquid-chromatography. Fecal excretion of total bile acids was not different during the periods of FO and CO-supplementation (301.9 vs. 320.3 mg/day). However, a non-significant trend to a lower daily excretion of the secondary bile acid lithocholic acid was found after FO compared to CO-ingestion (99.6 vs. 109.4 mg/day; p=0.22). Since secondary bile acids are known promotors of colon carcinogenesis, these findings may implicate a favorable situation with respect to colon cancer prevention.
    Notes: Zusammenfassung Verschiedene Studien weisen auf einen protektiven Effekt von Fischöl bei der Kolonkarzinomentstehung hin. Mögliche Einflüsse auf die muscosale Prostaglandin-E2-Synthese wurden hierbei als Wirkungsmechanismus beschrieben. Zusätzliche Effekte auf die fäkale Exkretion von Gallensäuren könnten ebenso von Bedeutung sein, da insbesondere sekundäre Gallensäuren als Promotoren bei der Kolontumorentstehung angesehen werden. In der vorliegenden Studie wurde bei 12 gesunden Probanden der Effekt einer täglichen Supplementierung mit 11 g Fischöl (FO) bzw. Maiskeimöl (MO) über jeweils 4 Wochen zusätzlich zu einer fettreduzierten Basiskost (30 % der Gesamtenergie als Fett) auf die fäkale Exkretion von Gallensäuren untersucht. Die Analyse des fäkalen Gallensäurenspektrums erfolgte gaschromatographisch. Die Gesamtausscheidung an Gallensäuren war unter FO nicht signifikant verschieden von derjenigen unter MO (301,9 vs. 320,3 mg/Tag). Unter FO ergab sich jedoch eine tendenziell niedrigere Exkretion der sekundären Gallensäure Lithocholsäure als unter MO (99,6 vs. 109,4 mg/Tag, p=0,22). Da sekundäre Gallensäuren als ein wesentlicher Promotor der Kolonkarzinogenese angesehen werden, sind diese Veränderungen positiv im Hinblick auf eine mögliche Kolonkarzinomprävention zu werten.
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    European journal of nutrition 34 (1995), S. 243-244 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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    European journal of nutrition 34 (1995), S. 245-251 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 86
    ISSN: 1436-6215
    Keywords: Deep-fat frying ; sunflower oil ; column and HPSE chromatographies ; color index ; acid value ; UV absorption ; Ölbad-Fritierung ; Sonnenblumenöl ; Säulen- und HPSE-Chromatographie ; Farbindex ; Säurezahl ; Refraktionsindex ; UV-Absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Chemische und physikalische Standardkennzahlen, wie zum Beispiel der Refraktions-und Farbindex, die Säurezahl und der K270-Wert, wurden mit den Gehalten an polaren Verbindungen sowie spezifischen thermooxidativen und hydrolytischen Fettbestandteilen verglichen, die in einem Sonnenblumenöl, das 75 mal zum Fritieren von Kartoffeln benutzt worden war, entstanden sind. Der Farbindex, die Säurezahl, der K270-Wert und der Gehalt an polaren Verbindungen stiegen signifikant (p〈0,05) nach 30 Fritierungen. Anschließend stabilisierten sich die drei letztgenannten Indices. Der Inhalt an polymeren Verbindungen und Triglyceridendimeren stieg signifikant nach 30 Fritierungen an (p〈0,05), während die oxidierten Triglyceride keine signifikante Steigerung aufwiesen. Der Gehalt an Diglyceriden und freien Fettsäuren, als Maß der hydrolytischen Vorgänge, zeigte während des Fritierprozesses keine signifikante Veränderung. Die signifikanten Korrelationen zwischen der Säurezahl und dem Gehalt an polaren Verbindungen, den dimeren und polymeren Triglyceriden und den oxydierten Triglyceriden, zwischen dem Farbindex und dem Gehalt an polaren Verbindungen und polymeren Triglyceriden, oder zwischen dem K270-Wert und den polymeren Triglyceriden zeigen, daß diese einfachen Standard-Methoden benutzt werden können und genauso nützlich sind wie mehr spezifische Methoden zur Bewertung von Fritierprozessen, wenn man die Ausgangswerte aller dieser Indices kennt.
    Notes: Summary Standard chemical and physical indexes, such as color index, acid value, and K270 were compared with the polar content and the specific thermoxidative and hydrolytic compounds originated during 75 potato fryings with sun-flower oil. The color index, acid value, K270 and total polar content showed a significant increase (p〈0.05) after the first 30 fryings, followed by a tendency of the last three indexes to reach a near-steady state. Triglyceride polymers and triglyceride dimers showed a significant increase (p〈0.05) after 30 fryings, while the oxidized triglycerides were not increased significantly after 30 fryings. The amount of diglycerides and free fatty acids related to hydrolytic alteration did not change significantly throughout the frying operations. The significant correlations between acid value and total polar content, triglyceride dimers, triglycerides polymers and oxidized triglycerides, or between color index and polar content and triglyceride polymers or between K270 and triglyceride polymers indicate that these simple and standard methods can be applied and they are as useful as more specific methods of evaluation in the monitoring of frying operations, provided that initial values of all of these indexes are available.
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    Lasers in medical science 10 (1995), S. 37-42 
    ISSN: 1435-604X
    Keywords: Enamel ; Etch ; Laser ; Acid ; Nd-YAG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Acid etching is regarded as one of the main means of providing additional retention in aesthetic dentistry. Alternative methods of achieving bonding to tooth tissue which have been proposed include laser etching. Conflicting results on bond strength to enamel have been reported for laser etching. Here the tensile bond strength of composite resin to acid- and laser-etched enamel was measured and the topographical differences between the surfaces were evaluated using the scanning electron microscope. The laser used was a pulsed Nd-YAG laser at 10 pulses per second with a pulse length of 150μs, 80mJ pulse−1, 1.064μm wavelength. The results obtained indicate that the bond strength of laser-etched enamel was significantly lower than that of acid-etched enamel. In this study the difference may be attributable to the chromophore used. Variations in the rate of traverse of the laser tip across the surface did not appear to produce significant alterations in the bond strength.
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  • 88
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    Lasers in medical science 10 (1995), S. 31-36 
    ISSN: 1435-604X
    Keywords: Embryonal carcinoma ; F9 cells ; Laser ; Hyperthermia ; Nigericin ; Acidosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract The aim of this study was to investigate how acidosis affects the sensitivity of F9 embryonal carcinoma cells to conventionally induced hyperthermia and Nd-YAG laser-induced laserthermia. Nigericin, a polyether ionophore, was used to reduce the intracellular pH to 6.8, while the control cells were maintained at a physiological pH of 7.4. Acidosis increased the heat sensitivity significantly. After the water bath only 75% of the acidotic F9S1 cells were viable, whereas all of the control cells at pH 7.4 survived. When the laser was used, the difference was even more pronounced. Only 9% of the acidotic cells were viable after a 2-min treatment and 0.2% after a 4-min treatment. At physiological pH a 2-min treatment left 41% of the cells viable and a 4-min treatment 2%. This study showed that laserthermia is significantly more effective in killing cells with low intracellular pH than it is in killing cells with normal intracellular pH. The core of a tumour is often acidotic and thus radioresistant. It is suggested that laserthermia could be a good choice when treating acidotic radioresistant cancer cells, and its effect as an adjuvant to radiation therapy should be investigated.
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    Lasers in medical science 10 (1995), S. 157-163 
    ISSN: 1435-604X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Diode lasers are now capable of delivering up to 60 W of power down thin optical fibres, and their medical applications have increased considerably over the past 5 years. Most of the recent experimental and clinical work has been performed using the 805 nm diode laser wavelength, which is more heavily absorbed and is less penetrating than the 1064 nm Nd-YAG wavelength in most tissues. In contact and non-contact mode, the overall tissue effects from the diode laser are similar to the Nd-YAG laser, but with interstitial therapy the 805 nm wavelength produces significantly greater necrosis than the 1064 nm wavelength. Experimental work has established the effectiveness of the diode laser and clinical work has confirmed its suitability for a wide variety of procedures. Diode lasers have the major advantages of being small, compact, portable, efficient, easy to use and virtually maintenance free; they are likely to replace more cumbersome lasers for many medical applications.
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  • 90
    ISSN: 1435-604X
    Keywords: Transmyocardial revascularization ; Lasers ; Coronary artery disease ; Ischaemia ; Tissue hibernation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Transmyocardial revascularization (TMR) is a puncture technique proposed as a solution for patients with coronary artery disease who cannot be efficiently treated with the standard revascularization procedures such as bypass surgery or percutaneous transluminal coronary angioplasty (PTCA). The studies presented in this review have investigated the use of lasers to revascularize ischaemic myocardium. Needle puncture methods are also briefly described. The results from experimental studies are not conclusive but the encouraging clinical reports raise further questions about the mechanism of angina relief.
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  • 91
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    Lasers in medical science 10 (1995), S. 93-104 
    ISSN: 1435-604X
    Keywords: Copper vapour laser ; Electron microscopy ; Illumination time ; Numerical modelling ; Optimal treatment ; Port-wine stain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract This paper reports the electron microscopy results obtained from two patients who were treated with 5 W of yellow (578 nm) light from a copper vapour laser with an illumination time of 3.6 ms and a 0.3 mm spot diameter. The endpoint of treatment was transient blanching. Following treatment, erythema was observed. There was minimal damage to the epidermis and non-vascular tissue such as the nerve fibres. There was severe damage to the endothelial cells of the ectatic vessels. Twenty-four hours after treatment, platelet activation and collagen were present, indicating that these vessels were no longer viable. Theoretical calculations are used to determine the flow of heat within and away from a 50μm diameter vessel. From this, heating of the entire vessel is shown to occur with illumination times of 4 ms, with minimal heating of the non-vascular tissue. Shorter illuminations do not heat the entire vessel, while the use of longer illumination times will cause excessive damage to the surrounding non-vascular tissue. Illumination times close to 4 ms must be regarded as optimal.
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  • 92
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    Lasers in medical science 10 (1995), S. 13-18 
    ISSN: 1435-604X
    Keywords: Photodynamic therapy ; Larynx ; Oval cavity ; Light dose rates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Photodynamic therapy (PDT) has the potential to treat early carcinomas of the oral cavity and larynx while preserving normal tissue. However, normal tissues retain the photosensitizing agents and may be activated by high light fluence and dose rates resulting in normal tissue necrosis. The effects of varying dose rates of light delivery on various tissues in the upper aerodigestive tract have not been evaluated to date and are necessary to determine a ‘therapeutic light dose range’ that will result in selective tumour necrosis. Thirty adult mongrel dogs received intravenous Photofrin, 2 mg kg−1, 48 h prior to PDT treatment. Photodynamic therapy was administered to the tongue, buccal mucosa and larynx with a microlens fibre and implantable cylindrical diffuser at various dose rates from 20 to 125 J cm−2 at 150 mW cm−2. At the same dose rate of light delivery, the tongue was the most sensitive organ, followed by the buccal mucosa, and last by the larynx. The differential tissue effect of identical dose rates of therapy must be taken into account when administering PDT so that selective tumour necrosis with normal tissue preservation may be achieved. This study indicates the need to perform evaluations of the effect of PDT on other tissue types in an animal model with each new photosensitizer prior to administering PDT to those areas in humans.
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  • 93
    ISSN: 1435-604X
    Keywords: Nerve conduction ; Laser therapy ; Skin temperature ; Biostimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract The effects of low-intensity near-infra-red laser irradiation (820 nm; 1.5 and 9.0 J cm−2; pulsed at 12 Hz, 73 Hz and 5 kHz) upon peripheral neurophysiology and skin temperature were investigated using antidromic conduction studies in the human median nerve in vivo. Healthy human volunteers (n = 90) were recruited and allocated randomly to either a control group (n=10) or one of eight experimental groups (two radiant exposures, 1.5 J cm−2 and 9.0 J cm−2 at one of three pulse repetition rates, 12 Hz, 73 Hz or 5 kHz, in addition to a placebo group for each radiant exposure;n = 10 all groups). Analysis of variance (ANOVA) demonstrated a significant (p≤0.05) decrease in skin temperature following irradiation at the lowest radiant exposure (1.5 J cm−2) combined with pulse repetition rates of 73 Hz and 5 kHz, with the greatest effect at 73 Hz. These changes in skin temperature were coupled with increases in negative peak latency (NPL); ie changes in NPL were inversely related to changes in skin temperature. However, in contrast to the authors' previous findings using continuous wave (CW) laser irradiation, differences in NPL were not found to be significant. These findings, therefore, provide little evidence of the neuro-physiological effects of low-intensity infra-red irradiation at the dosage levels and pulse repetition rates used here.
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  • 94
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    Lasers in medical science 10 (1995), S. 267-272 
    ISSN: 1435-604X
    Keywords: Blood flow pulsatility ; Human infants ; Laser Doppler velocimetry ; Retinal blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract The present study was conducted to assess the feasibility of laser Doppler velocimetry in young infants, as a prelude to ultimately undertaking such measurements in premature infants. A portable, unidirectional laser Doppler velocimeter was developed based on a Kowa RC-2 hand-held fundus camera. Six infants between 1 and 21 weeks of age were studied. Relative red blood cell velocity (δfmax) at the centre of retinal arteries was measured over approximately 10 heart cycles. A pulsatility parameter (P=1−δfmax.dia/δfmax.sys), a summary index of vascular status, was determined from the average diastolic and systolic values of δfmax. Velocity waveforms were obtained in four of the six infants. Arterial pulsatility for the group was 0.63±0.13. Precise non-invasive measurement of arterial red blood cell velocity waveforms in young infants was achieved. The high signal-to-noise ratio and temporal resolution of this data suggest that relative measurements of retinal blood flow may permit assessment of haemodynamic changes in premature infants.
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  • 95
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    Polymer bulletin 34 (1995), S. 677-684 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The polymer-solvent interaction parameter, χ12, was determined for poly(4-hydroxystyrene) (P4HS) at 443 and 463 K, by inverse gas chromatography (IGC) using several probes. The partial molar heat of mixing at infinite dilution in the polymer was also calculated. The solubility parameter δ2 of P4HS has been obtained by using the method developed by DiPaola-Baranyi and Guillet. Moreover using the equation-of-state theory the contact interaction energy, X12, was also determined. The variation of the interaction parameters were correlated with the size and kinds of atoms present in the molecules.
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    Polymer bulletin 34 (1995), S. 691-698 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Novel amphiphilic N-alkyl-, N-decenyl-, and N-alkyl-N'-methyl-semicarbazones of maltose and maltotriose with CnH2n+1 alkyl chains and n=8,9,10,11,12,16 were applied as emulsifiers in styrene emulsion polymerization. Surfactant properties, emulsion polymerization, and rheology were examined as a function of amphiphile molecular architectures. Both critical micelle concentration and average polystyrene particle size increased with decreasing alkyl chain length. Using N-methyl-N-[11-(acryloylamino)-undecanoyl]-glucamine comonomer in a starved feed emulsion polymerization process, it was possible to prepare uniform polystyrene latex with glucamide surface.
    Type of Medium: Electronic Resource
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  • 97
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A PVCILO method has been used to compare the stabilization energies of the electron donor electron acceptor complexes between methyl vinyl ether as donor and the enophiles, 4-phenyl 1-1,2,4-triazoline-3,5-dione (1) and N-phenylmaleimide (2), respectively, as acceptor. A stabilization energry difference in favor of the more reactive 1 was obtained, which is being interpreted as an explanation for the enhanced rate of reaction of 1 vs 2, often by factors 〉104.
    Type of Medium: Electronic Resource
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  • 98
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Model silicone networks obtained by hydrosilation of vinyl terminated polydimethylsiloxane chains have been used extensively to verify molecular theories of rubber elasticity. In these networks, the maximum extent of reaction obtained during cross linking considerably affects their final structure. The degree of completion of the hydrosilation reaction depends on the concentration of reactive groups. A recursive approach and kinetic data from the literature are used to show that, for this particular reaction, perfect networks, i.e. those with high concentration of elastically active network chains, are only obtained when a relatively high concentration of reactive groups is present in the system. This critical concentration corresponds in a bulk reaction to polydimethylsiloxane chains with a number average molecular weight lower than 10,000.
    Type of Medium: Electronic Resource
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  • 99
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Copolymers of N-(2-hydroxyethyl)ethyleneimine and succinic anhydride without initiator were prepared under different experimental conditions. The composition of the copolymers was determined by elemental analyses and1H-NMR spectroscopy. From the results of FT-IR and1H-NMR spectroscopy a scheme of copolymerization via zwitterion is presented which includes an esterification reaction of the pendant hydroxylic groups.
    Type of Medium: Electronic Resource
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  • 100
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary This study investigated the copolymerization of ethylene with 1-hexene using the homogeneous Et[Ind]2ZrCl2 and [Ind]2ZrCl2 catalysts. The Et[Ind]2ZrCl2 catalyst gave a higher catalytic activity than the [Ind]2ZrCl2 and also showed a better incorporation of 1-hexene for the same comonomer concentration in the feed. Thermal analysis (DSC) and viscosity measurements showed that an increase of the 1-hexene incorporated in the copolymer results in a decrease of the melting point, crystallinity and molecular weight of the polymer formed. The reactivity ratios for ethylene and 1-hexene confirmed the more successful incorporation of the comonomer for the polymerization catalyzed by Et[Ind]2ZrCl2.
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