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An integral method for the analysis of blood flow (1971)

Tsou, F. K. ; Chou, P. C. ; Frankel, S. N. ; [et al.]

Springer

Bulletin of mathematical biology 33 (1971), S. 117-128

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ISSN: 1522-9602

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Mathematics

Notes: Abstract The existing methods to solve the problems of pulsatile flow in the cardiovascular system are based on either linear axisymmetric equations or non-linear one-dimensional equations. The solutions thus obtained give only a mediocre comparison with measurements. In this paper, a non-linear axisymmetric theory is proposed. The starting point of the present theory is a third degree polynomial representation of the velocity profile. Integral methods are then applied to obtain the governing equations. To ascertain the accuracy of the theory proposed above, the calculations for a simple case involving pulsatile flow in a long rigid tube were performed. The results are: (a) the average velocities compare very well with exact solutions and (b) the velocity profiles for a given frequency agree very well with exact solutions for flow in small tubes, but tend to differ as tube size is increased.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02476669

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Genotype/phenotype correlation in affected individuals of a family with a deletion of the entire coding sequence of the connexin 32 gene (1998)

Ainsworth, P. J. ; Bolton, C. F. ; Murphy, B. C. ; [et al.]

Springer

Human genetics 〈Berlin〉 103 (1998), S. 242-244

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ISSN: 1432-1203

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract X-linked Charcot-Marie-Tooth disease (CMTX) is a peripheral nerve disorder that has been linked to mutations in the connexin 32 gene (Cx32). These mutations have been shown to be genetically heterogeneous, though recurrences of specific mutations in apparently unrelated families have been seen. The majority of mutations have been shown to be missense, resulting in non-conservative amino acid changes. A few mutations resulting in a premature termination of protein translation, including both nonsense mutations as well as frameshifting microdeletions, have been documented. We would like to report a deletion mutation that appears to eliminate the entire coding sequence of the Cx32 gene, but which has been shown to segregate with a clinical phenotype not unlike that seen in individuals with a less severe alteration of the Cx32 gene. The causes at a cellular level of the CMTX phenotype are still not fully clear, though there has been speculation that these may involve a dominant negative effect where the mutant connexin 32 suppresses the function of other connexins. Studies of kindreds such as this, where in CMTX-affected males the Cx32 gene product is totally absent, will help us to better understand the molecular mechanisms underlying the clinical phenotype associated with this disorder.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004390050812

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Study of power generating implantable electrodes (1968)

Massie, H. ; Racine, P. ; Pasker, R. ; [et al.]

Springer

Medical & biological engineering & computing 6 (1968), S. 503-516

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ISSN: 1741-0444

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Description / Table of Contents: Sommaire Une cellule électrochimique implantable en platine-alumine peut fournir une puissance électrique d’environ 50–75 μW. Les implantations ont été pratiquées sur 12 lapins pour des périodes allant jusqu’à 200 jours. L’intensité de la réaction initiale du tissue et l’accumulation des produits d’oxydation de l’alumine insolubles apparaissent être les facteurs limitant la puissance utile disponible. Ces données, ainsi que la faible puissance requise par les dispositifs électroniques implantés (pacemakers, radio-sondes, etc.) laissent penser que l’on pourra utiliser ces types d’électrodes comme source de puissance de longue durée.

Abstract: Zusammenfassung Etwa 50 bis 75 μW (Mikrowatt) elektrischer Leistung können von einer implantierbaren elektrochemischen Platin-Aluminium-Zelle abgeleitet werden. Bei Kaninchen wurden sie bis zu 200 Tagen Dauer implantiert. Das Ausmaß der anfänglichen Gewebsreaktion und der Ansammlung unlöslicher Aluminiumoxydationsprodukte scheinen die Nutzleistung zu begrenzen. Diese Angaben und der niedrige Strombedarf implantierbarer elektronischer Geräte (Schrittmacher, Telemetrie usw.) lassen eine nutzbringende Anwendung dieser Elektrodentypen als Dauerstromquellen erwarten.

Notes: Abstract Approximately 50–75 μW (microwatts) of electrical power can be obtained from an implantable platinum-black aluminum electrochemical cell. The implantations have been conducted in twelve rabbits for periods up to 200 days. The intensity of the initial tissue reaction and accumulation of insoluble aluminum oxidation products appear to be the factors limiting useful power available. These data, together with the low power requirement of implantable electronic devices (pacemakers, telemeters, etc.), suggest the feasibility of using these types of electrodes as a long term power source.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02474289

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