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  • 1
    Electronic Resource
    Electronic Resource
    Filter Banks and Neural Network-based Feature Extraction and Automatic Classification of Electrogastrogram (1999)
    Springer
    Annals of biomedical engineering 27 (1999), S. 88-95 
    Details
    ISSN: 1573-9686
    Keywords: Electrogastrography ; Gastric motility ; Stomach ; Filter banks ; Neural networks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Dysrhythmia in gastric myoelectrical activity has been frequently observed in patients with gastric motor disorders and gastrointestinal symptoms. The assessment of the regularity of gastric myoelectrical activity is of great clinical significance. The aim of this study was to develop an automated assessment method for the regularity of gastric myoelectrical activity from the surface electrogastrogram (EGG). The method proposed in this paper was based on the filter bank and neural network. First, the EGG signal was divided into frequency subbands using filter bank analysis. Second, a parameter called the subband energy ratio (SER) was computed for each subband signal. A multilayer perceptron neural network was then used to automatically classify the EGG signal into four categories: bradygastria, normal, tachygastria, and arrhythmia, using the SER as the input. The EGG recording was made using the standard method of electrogastrography by placing electrodes on the abdominal surface. The study was performed in 40 patients with various gastric motor disorders, ten healthy adults, and ten healthy children. The neural network was trained and tested using the EGG data obtained from the patients. The regularity of gastric myoelectrical activity was assessed based on the classification of the minute-by-minute EGG segments. Using the running spectral analysis method as a gold standard, the proposed automated method had an accuracy of 100% for the training set and 97% for the test set. It was concluded that the proposed method provides an accurate and automatic assessment of the regularity of gastric myoelectrical activity from the EGG. © 1999 Biomedical Engineering Society. PAC99: 8780-y, 8717-d, 0705Mh, 0270Hm
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1114/1.151
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  • 2
    Electronic Resource
    Electronic Resource
    Solute-membrane interactions in hyperfiltration (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 1809-1822 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The performances of several composite membranes (PEC-1000, Teijin, HR-95, HR-98) and one asymmetric membrane (Solrox SC-200) in hyperfiltration are compared at 25°C using different aqueous feed solutions (0.1M and 0.5M NaCl, 0.5M 1,3-and 1,4-dioxan, 0.1M benzyl alcohol and 2-methoxybenzyl alcohol, 1,2- and 1,4-butandiol, and Triton feed solution). The effects of solute dissociation, polarization, and hydrogen bonding ability on solute permeability are discussed; steric effects are also being considered. Strong solute-membrane interactions are exhibited in hyperfiltration by systems with distinct hydrogen bonding capabilities of the solute with functional sites of the membrane matrix. Knowledge of solute-membrane interactions can be useful for elaborating separation and transport mechanisms.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330532
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  • 3
    Electronic Resource
    Electronic Resource
    Adaptive spectral analysis of cutaneous electrogastric signals using autoregressive moving average modelling (1990)
    Springer
    Medical & biological engineering & computing 28 (1990), S. 531-536 
    Details
    ISSN: 1741-0444
    Keywords: Autoregressive moving average modelling ; Electrogastrography ; Gastric motility ; Gastric slow wave ; Spectral analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The recording of the human, gastric myoelectrical activity, by means of cutaneous electrodes is called electrogastrography (EGG). It provides a noninvasive method of studying electrogastric behaviour. The normal frequency of the gastric signal is about 0·05 Hz. However, sudden changes of its frequency have been observed and are generally considered to be related to gastric motility disorders. Thus, spectral analysis, especially online spectral analysis, can serve as a valuable tool for practical purposes. The paper presents a new method of the adaptive spectral analysis of cutaneous electrogastric signals using autoregressive moving average (ARMA) modelling. It is based on an adaptive ARMA filter and provides both time and frequency information of the signal. Its performance is investigated in comparison with the conventional FFT-based periodogram method. Its properties in tracking time-varying instantaneous frequencies are shown. Its applications to the running spectral analysis of cutaneous electrogastric signals are presented. The proposed adaptive ARMA spectral analysis method is easy to implement and is efficient in computations. The results presented in the paper show that this new method provides a better performance and is very useful for the online monitoring of cutaneous electrogastric signals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442603
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and properties of copolymers from 2-hydroxyethyl methacrylate-linked nonsteroidal antiinflammatory agents with methacrylic acid (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1481-1490 
    Details
    ISSN: 0887-624X
    Keywords: ibuprofen ; ketoprofen ; naproxen ; copolymer reactivity ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three nonsteroidal antiinflammatory drugs, 2-(4-isobutylphenyl)-propionic acid (ibuprofen), 2-(3-benzoylphenyl)-propionic acid (ketoprofen), and 2-(6-methoxy-2-naphthyl)-propionic acid (naproxen), were covalently linked with 2-hydroxyethyl methacrylate (HEMA). The drug-linked HEMA (M1) (ibuprofen-linked HEMA abbreviated as HI; ketoprofen-linked HEMA as HK, and naproxen-linked HEMA as HN), were respectively copolymerized with methacrylic acid (M2), MA, to obtain macromolecular prodrugs. The compositions of the copolymers were determined by means of a 1H-NMR spectroscopy and monomer reactivity ratios were estimated using the Kelen-Tüdös linear differential equation. The reactivity ratios are: r1 = 0.101 ± 0.012, r2 = 1.071 ± 0.065 for HI-MA; r1 = 0.344 ± 0.066, r2 = 0.966 ± 0.032 for HN-MA, and r1 = 0.650 ± 0.182, r2 = 1.032 ± 0.106 for HK-MA, respectively. The monomer reactivity toward to MA radical estimated from 1/r2 values is almost same for all three monomers (1/r2 ∼ 1). The glass transition temperatures of three drug-linked homopolymers go hand in hand with the steric hindrance of three drugs, i.e., ketoprofen 〉 naproxen ≫ ibuprofen calculated the minimum energy by computer molecular modeling. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1481-1490, 1998
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    A study on the plasma polymerization of some cyano-containing compounds and their electrical properties (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 3799-3809 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma polymerization of some cyano-containing organic compounds was carried out at 13.56 MHz from the gas phase. The resulting polymer films were smooth and pinhole free. The electrical conductivities of the polymer films varied from 10-12 to 10-7 S cm-1 depending upon which cyano-containing monomer was used. The Al/polymer film/ITO (indium-tin oxide) sandwich cells made from the films demonstrated a photovoltaic effect, and some of them showed good rectifying behavior. Infrared spectroscopy (IR) and ultraviolet spectroscopy (UV) were utilized to characterize the structure of the product polymers. The effects of the original structure in the starting monomers on the structure of the resulting polymers are investigated. The influence of incident light intensity on the photovoltaic characteristics was also investigated.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080271120
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  • 6
    Electronic Resource
    Electronic Resource
    Optimized Overcomplete Signal Representation and its Applications to Time-frequency Analysis of Electrogastrogram (1998)
    Springer
    Annals of biomedical engineering 26 (1998), S. 859-869 
    Details
    ISSN: 1573-9686
    Keywords: Spectral analysis ; Matching pursuit ; Stomach ; Gastric motility ; Electrogastrography ; Evolutionary programming ; Signal analysis ; Electrogastrogram
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The electrogastrogram (EGG) is a surface measurement of gastric myoelectrical activity. The normal frequency of gastric myoelectrical activity in humans is 3 cycles/min. Abnormal frequencies in gastric myoelectrical activity have been found to be associated with functional disorders of the stomach. The aim of this article was, therefore, to develop new time-frequency analysis methods for the detection of gastric dysrhythmia from the EGG. A concept of overcomplete signal representation was used. Two algorithms were proposed for the optimization of the overcomplete signal representation. One was a fast algorithm of matching pursuit and the other was based on an evolutionary program. Computer simulations were performed to compare the performance of the proposed methods in comparison with existing time-frequency analysis methods. It was found that the proposed algorithms provide higher frequency resolution than the short time Fourier transform and Wigner-Ville distribution methods. The practical application of the developed methods to the EGG is also presented. It was concluded that these methods are well suited for the time-frequency analysis of the EGG and may also be applicable to the time-frequency analysis of other biomedical signals. © 1998 Biomedical Engineering Society. PAC98: 8780+s, 0705Kf
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1114/1.69
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  • 7
    Electronic Resource
    Electronic Resource
    Development of a recovery process for novobiocin (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 533-549 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A periodic countercurrent whole beer process was developed for the recovery of novobiocin to eliminate the high cost of mycelium filtration and accompanying antibiotic losses in the filter cake. In such a process screened, but unfiltered, novobiocin fermentation beer is contacted with a special grade of an anionic-exchange resin in a series of specially designed, well mixed columns. Each column is fitted with a screen sized to retain resin within the column but allow the cells to press. Periodically the lead column is isolated from the column train, washed free of beer solids, and eluted. A freshly eluted column is placed in the trail position to allow countercurrent operation. The eluate is then processed to crystalline product.A mathematical model for the sorption of novobiocin was developed based on a suitable continuity equation and mass transfer and equilibrium relationships determined in the laboratory. Digital computations of this model correlated well with laboratory and pilot plant data, and predicted well the performance of the production units. This simulation has been in continued use to predict and reoptimize plant operation as process changes (such as improved beer titers, increased production rate, and the evaluation of superior ion-exchange resins) occurred or were anticipated.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260150309
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  • 8
    Electronic Resource
    Electronic Resource
    Falling film evaporation of binary mixtures (1994)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 40 (1994), S. 207-214 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The interactive effects of heat and mass transfer in evaporation of binary mixtures flowing as falling films on vertical surfaces was investigated. Evaporative heat-transfer coefficients were measured for aqueous mixtures of ethylene and propylene glycol, with boiling ranges up to 55°C. Tests were carried out at atmospheric pressure with heat fluxes ranging from 3,000 to 25,000 W/m2, and film Reynolds numbers ranging from 300 to 3,000. Results indicated that the heat-transfer coefficient for mixtures depends weakly on wall superheat and film Reynolds number, but strongly depends on mixture composition. Analysis of the results indicates that mass-transfer resistance in the liquid film causes significant elevation of the interface temperature, causing a reduction of the effective temperature driving force. A semiempirical model for correlation of the interactive heat-and mass-transfer phenomena is proposed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690400203
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  • 9
    Electronic Resource
    Electronic Resource
    A mechanistic study of oxygen transfer in aqueous systems (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 13 (1971), S. 271-292 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Oxygen transfer coefficients were evaluated for a 14-liter stirred tank fermentor equipped with an oxygen probe, employing elemental copper adsorbed on a weakly basic anion-exchange resin as a solid phase oxygen acceptor. The use of a solid phase oxygen acceptor allowed evaluation of mass transfer resistances associated with the solid phase, and the effect of an oxygen adsorbing solid phase on the overall oxygen transport system, portions of the oxygen transfer process that are neglected by the conventional sulfite oxidation method commonly employed. It was concluded from the data obtained that a transport pathway involving transfer of oxygen to particles present near the air-water interface was a significant oxygen transport pathway for the system studied. Oxygen probe measurements performed on the bulk liquid did not recognize this pathway, suggesting that data taken on biological systems by use of techniques involving oxygen concentration measurements in the bulk liquid may not give the true oxygen absorbing capacity of a system.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260130209
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  • 10
    Electronic Resource
    Electronic Resource
    Wavelet-based density estimation and application to process monitoring (1997)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 1227-1241 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An application of wavelets and multiresolution analysis to density estimation and process monitoring is presented. Wavelet-based density-estimation techniques are developed as an alternative and superior method to other common density-estimation techniques. Also shown is the effectiveness of wavelet estimators when the observations are dependent. The resulting density estimators are then used in defining a normal operating region for the process under study so that any abnormal behavior by the process can be monitored. Results of applying these techniques to a typical multivariate chemical process are also presented.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690430512
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