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  • 1
    Electronic Resource
    Electronic Resource
    Size principle and information theory (1997)
    Springer
    Biological cybernetics 76 (1997), S. 11-22 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract. The motor units of a skeletal muscle may be recruited according to different strategies. From all possible recruitment strategies nature selected the simplest one: in most actions of vertebrate skeletal muscles the recruitment of its motor units is by increasing size. This so-called size principle permits a high precision in muscle force generation since small muscle forces are produced exclusively by small motor units. Larger motor units are activated only if the total muscle force has already reached certain critical levels. We show that this recruitment by size is not only optimal in precision but also optimal in an information theoretical sense. We consider the motoneuron pool as an encoder generating a parallel binary code from a common input to that pool. The generated motoneuron code is sent down through the motoneuron axons to the muscle. We establish that an optimization of this motoneuron code with respect to its information content is equivalent to the recruitment of motor units by size. Moreover, maximal information content of the motoneuron code is equivalent to a minimal expected error in muscle force generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004220050317
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  • 2
    Electronic Resource
    Electronic Resource
    Hypothenar hammer syndrome in sports (1996)
    Springer
    Knee surgery, sports traumatology, arthroscopy 4 (1996), S. 167-170 
    Details
    ISSN: 1433-7347
    Keywords: Hypothenar hammer syndrome ; Distal ulnar artery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Sports Science
    Notes: Abstract Repetitive blunt trauma or single severe trauma to the hypothenar region may lead to traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome, HHS). In the sports-related literature we found and analysed isolated cases attributed to injuries sustained during sporting activities such as baseball, badminton, handball, football, frisbee, softball, karate, weight-lifting and hockey. Further, we report the case of an amateur golf player with ischaemic symptoms of his left hand, where angiography revealed filling defects in the digital arteries associated with a corkscrew-like configuration of the distal ulnar artery. Magnetic resonance imaging (MRI) scan demonstrated, at the level of the hamulus ossis hamati, accessory fibres of m. palmaris brevis forming a sling around the ulnar artery. Treatment by resection of the ulnar artery. Treatment by resection of the thrombosed a. ulnaris segment and replacement with an autologous vein graft resulted in complete relief of symptoms. Histological sections revealed partially organized thrombi adherent to the intimal surface with fragmentation of the internal elastic membrane, indicating a traumatic genesis. As the mechanism of injury, we suspected intensive golf playing with the grip style and subsequent motions leading to pressure injury of the hypothenar area and the underlying ulnar artery. Contraction of the anomalous muscle belly may have additionally compressed the artery, slowing down the arterial flow and promoting thrombosis. In most reported cases including our own, it took a relatively long time until the cause of the disease as traumatic was found and accepted. The initial repetitive blunt or single severe trauma initiaing the HHS can easily be overlloked or ignored. After intimal damage of a. ulnaris, the beginning of symptoms may be prolonged and mislead one into thinking the cause is a collagen or vasospastic disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01577412
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  • 3
    Electronic Resource
    Electronic Resource
    High spin structure study of the light Odd-A f7/2 nuclei: 45Sc, 45Ti and 43Ca (1998)
    Springer
    The European physical journal 2 (1998), S. 157-171 
    Details
    ISSN: 1434-601X
    Keywords: PACS:27.40+z 39 ≤ A ≤ 58 – 21.10.Tg Lifetimes – 21.60.Cs Shell model – 21.60.Ev Collective models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: High-spin states in 45Sc, 45Ti and 43Ca were studied by means of multiple γ- and γ-recoil-coincidences with the use of the GASP array and the Recoil Mass Spectrometer. The nuclei were populated in the 60 MeV 18O +30Si reaction. For the DSAM lifetime measurement the 35Cl +12C reversed kinematics reaction was used. In the article, a complete description of the experimental techniques used in course of the performed experiments is presented. The level schemes and the detailed information on the observed state properties, including B(M1) and B(E2) transition rates are inserted as well as their shell model interpretation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100500050105
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  • 4
    Electronic Resource
    Electronic Resource
    Fusion around the barrier in 11,9Be +209Bi (1998)
    Springer
    The European physical journal 2 (1998), S. 227-231 
    Details
    ISSN: 1434-601X
    Keywords: PACS:25.70.Jj Fusion and fusion-fission reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The 9Be +209Bi fusion cross sections were measured in the range 37.5 MeV ≤ E lab ≤ 45.0 MeV at the Munich Tandem via the observation of ground state α-decay of the evaporation residues. Fusion cross sections of 209Bi with the “halo”11Be unstable projectile in the region around the Coulomb barrier were deduced from an experiment done with the same technique at the RIKEN Ring Cyclotron. Above the Coulomb barrier the 11Be cross sections are larger than the 9Be ones in agreement with theoretical predictions based on the larger 11Be halo radius. Also below the barrier these theories foresee the same behavior in disagreement with the experimental results, since the two cross sections are rather similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100500050111
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  • 5
    Electronic Resource
    Electronic Resource
    Optimization of the SPME device design for field applications (1999)
    Springer
    Fresenius' journal of analytical chemistry 364 (1999), S. 610-616 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Solid Phase Microextraction (SPME) is a powerful tool for field investigations. With the help of a portable gas chromatograph it can be used for fast analysis directly on-site, or it can be utilized for field sampling and then transported to the laboratory for instrumental analysis. In the latter case, it is important for the reliability of the results that losses of volatiles and contamination of the fiber during storage and transport are minimized. A number of dedicated devices, designed and built for SPME field sampling and storage, have been developed and tested. Sealing capacity of the prototypes was investigated by storing compounds ranging in volatility from methylene chloride to 1,3-dichlorobenzene on selected SPME fibers (100 μm PDMS, 65 μm PDMS/DVB and 75 μm Carboxen/PDMS) at different temperatures. Significant differences were noticed in storage capacity from coating to coating. A comparison between the field samplers optimized in this study and the field sampler commercially available from Supelco revealed advantages and limitations of each of the designs. A gas-tight valve syringe (50 μL SampleLock by Hamilton), modified in order to accommodate the SPME fiber, had the best storage capacity for very volatile compounds. With this device, over 80% of the initial amount of methylene chloride was retained by the 100 μm PDMS fiber after 24 h of refrigerated storage, which is a very good result considering that the PDMS coating is characterized by very low storage capacity for volatiles. Field sampling investigations with the SPME prototypes confirmed the usefulness of these devices for field analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051396
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  • 6
    Electronic Resource
    Electronic Resource
    Paradoxical embolism after a femoral fracture (1997)
    Springer
    Der Unfallchirurg 100 (1997), S. 908-912 
    Details
    ISSN: 1433-044X
    Keywords: Key words paradoxical embolism • fracture • foramen ovale ; Schlüsselwörter Paradoxe Embolie • Fraktur • Foramen ovale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In etwa 25 % der Fälle ist im Erwachsenenalter das Foramen ovale anatomisch offen, funktionell, bedingt durch den höheren Druck im linken Vorhof, aber geschlossen. Wenn z. B. durch eine Lungenembolie ein höherer Druck durch Rechtsherzbelastung im rechten Vorhof entsteht, kann sich ein funktionell normalerweise geschlossenes Foramen ovale wieder öffnen, und durch den eintretenden Rechts-links-Shunt der Weg für eine paradoxen Embolie gebahnt werden. Im vorliegenden Fall traten bei einer Patientin 20 Tage nach operativer Versorgung einer subtrochantären Oberschenkelfraktur mittels Kondylenplatte Wortfindungsstörungen auf. Die deshalb durchgeführte Magnetresonanztomographie (MRT) des Schädels zeigte einen frischen ischämischen Infarkt. Nachdem die übliche Durchuntersuchung mit Duplexsonographie der Karotiden keinerlei Erklärung für den ischämischen Infarkt ergeben hatte, wurde eine paradoxe Embolie über ein offenes Foramen ovale vermutet. Anschließend konnte sowohl duplexsonographisch eine frische Thrombose der V. femoralis superficialis als auch szintigraphisch eine Lungenembolie nachgewiesen werden. Die transösophageale Echokontrastkardiographie stellte ein spontan hämodynamisch wirksames offenes Foramen ovale dar. Der Fall zeigt, daß inapparente Beinvenenthrombosen durch zerebrale Defizite, wie z. B. Wortfindungsstörungen manifest werden können, und veranschaulicht den Pathomechanismus einer paradoxen Embolie.
    Notes: Summary The foramen ovale is anatomically open in 25 % of individuals, but functionally closed by the higher pressure in the left antrum. Right-to-left shunt and subsequent paradoxical embolism may occur when pressure in the left antrum rises, for example, as a result of pulmonary embolism. In the present case we demonstrate a patient who presented 20 days after osteosynthetic treatment of a femoral fracture with word-finding deficits. Cerebral MRT revealed a fresh ischemic insult. Duplex ultrasound of the legs showed a fresh thrombosis of the superficial femoral vein and scintigraphy of the lungs detected pulmonary embolism. Transesophageal contrast echocardiography trapped a hemodynamically spontaneous, open foramen ovale. Duplex ultrasound of the carotid arteries detected no pathological findings. Deep vein thrombosis and pulmonary embolism can be clinically unconspicuous and become manifest by cerebral deficits resulting from paradox embolism and cerebral ischemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050211
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  • 7
    Electronic Resource
    Electronic Resource
    Bilaterales Elastofibroma dorsi (1999)
    Springer
    Der Chirurg 70 (1999), S. 1357-1360 
    Details
    ISSN: 1433-0385
    Keywords: Key words: Elastofibroma dorsi ; Bilateral ; Literature review. ; Schlüsselwörter: Elastofibroma dorsi ; bilateral ; Literaturübersicht.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Ein 75 jähriger Patient stellte sich mit seit 2 Jahren langsam größenprogredienten Raumforderungen unterhalb beider Schulterblätter vor. Anamnestisch bestand ein Zustand nach proximaler Oberarmamputation linksseitig mit folgender prothetischer Versorgung. Klinisch zeigten sich direkt unter den Schulterblattspitzen beidseits 2 faustgroße Tumoren, die fest mit dem tiefer gelegenen Gewebe verwachsen waren. Sowohl magnetresonanztomographisch als auch intraoperativ stellte sich ein infiltratives Wachstum dieser Raumforderungen in die seitliche Thoraxmuskulatur und das Periost der Rippen sowie des Schulterblatts dar, so daß ein maligner Tumor vermutet wurde. Histopathologisch zeigte sich Bindegewebe mit zahlreichen eingelagerten fragmentierten und unregelmäßig konfigurierten elastischen Fasern und unscharfer Begrenzung zum umgebenden Fettgewebe, typisch für ein Elastofibrom. Für Malignität bestand kein Anhalt. Im vorliegenden Fall erscheint es wahrscheinlich, daß eine unphysiologische Belastung der oberen Extremitäten bei dem mit einer linksseitigen Oberarmprothese versorgten Patienten die Entstehung der beidseitigen Elastofibrome begünstigt hat. Das Elastofibrom ist ein seltener, gutartiger, fast immer subscapulär gelegener Weichteiltumor, der bevorzugt bei älteren Frauen auftritt. In etwa 10 % der Fälle findet sich ein bilaterales, meist asynchrones Wachstum. Klinisch und radiologisch stellen Lipome sowie Weichteilsarkome die wichtigsten Differentialdiagnosen dar. Andere seltene Elastofibromlokalisationen an Rumpf, Kopf und Extremitäten werden in der vorliegenden Arbeit aufgeführt.
    Notes: Summary. A 75-year-old man had painless, slowly enlarging tumors in the right and left infrascapular regions. Clinically, the tumors were nontender and semimobile. MR imaging and the operative exploration revealed tumors infiltrating the lateral thoracic muscles and periost of the scapula and underlying ribs. At surgery, the tumors were thought to be malignant, most likely liposarcomas. The histological examination showed the characteristic appearance of elastofibromas with spindle-shaped fibroblasts, which were separated by thick eosinophilic collagenous and elastic fibers. Elastofibromas are benign mesenchymal soft-tissue lesions that mainly affect elderly women. In 10 % of the patients bilateral, often asynchronous tumors are seen. Ninety-nine percent of the lesions are located in the subscapular region. Occasional elastofibromas have been described in the extremities, head, and in the abdominal and thoracic cavities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001040050794
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  • 8
    Electronic Resource
    Electronic Resource
    Living-donor liver transplantation in children (1999)
    Springer
    Langenbeck's archives of surgery 384 (1999), S. 528-535 
    Details
    ISSN: 1435-2451
    Keywords: Key words Living donor ; Liver transplantation ; Child ; Paediatric recipient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Introduction: Living- related liver transplantation (LRLT) for paediatric recipients was developed 10 years ago to overcome the high mortality on the waiting list. Since then, liver transplantation programs around the world have begun to employ this method with encouraging results. This review describes the actual status of LRLT in children, aspects of donor selection, donor risks, and surgical technique, as well as an update of the results of the leading LRLT programs in the world. The donor operation has matured to the stage of being a standardised, teachable procedure with a low risk of morbidity or mortality. However, there is a percentage of potential donations that have to be declined for medical or socio- psychological reasons. LRLT provides grafts of excellent quality and short cold ischemic times. A major advantage is the fact that the optimal moment for the transplantation procedure can be chosen. Together with split-liver techniques, LRLT has a positive effect on the general situation of the paediatric waiting list for liver transplantation, with a reduction of pre-transplant mortality to nearly 0%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004230050239
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  • 9
    Electronic Resource
    Electronic Resource
    Does break-up affect 9Be +209Bi fusion at the barrier? (1999)
    Springer
    The European physical journal 5 (1999), S. 7-11 
    Details
    ISSN: 1434-601X
    Keywords: PACS:25.70.Jj Fusion and fusion fission reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The 9Be +209Bi fusion cross sections were measured in the 36.0 MeV ≤ Elab≤ 50.0 MeV range, down to 0.6 mb, with high accuracy via in-beam detection of the ground state α-decay of the evaporation residues produced. The elastic scattering cross sections around 150° and 135° were also obtained with moderate angular resolution. The cross sections below the barrier are reproduced by coupled channel calculations which include only one break-up channel with a moderate strength and a phenomenological renormalization of the potential depth. These simple calculations overestimate the cross sections above the barrier most likely due to the fact that the 9Be break-up process becomes much stronger. The barrier distributions extracted do not have evident break-up signature since they show one-barrier structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100500050250
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  • 10
    Electronic Resource
    Electronic Resource
    Study of very neutron deficient nuclei 178Pt and 181Au (1999)
    Springer
    The European physical journal 4 (1999), S. 17-19 
    Details
    ISSN: 1434-601X
    Keywords: PACS:23.20.Lv Gamma transitions and level energies – 25.70.Jj Fusion and fusion-fission reactions – 27.70.+q 150 ≤ A ≤ 189
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The 178Pt and 181Au nuclei have been studied with the (230 MeV) 46Ti +142Nd fusion-evaporation reaction; γ-rays, evaporated particles and recoiling nuclei have been detected by the γ-array GASP + the Si ball ISIS + the recoil mass spectrometer RMS. The newly observed structures in 178Pt and 181Au are most probably built on the proton and quasi-proton h9/2 and i13/2 configurations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100500050199
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