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  • 1
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  A characteristic feature of the major histocompatibility complex (Mhc) polymorphism in mammals is the existence of allelic lineages shared by related species. This trans-species polymorphism has thus far been documented only in primates, rodents, and artiodactyls. In this communication we provide evidence that it also exists in cyprinid (bony) fishes at the class II A and B loci coding for the α and β polypeptide chains of the class II α : β heterodimers. The study has focused on three species of the family Cyprinidae, subfamily Rasborinae: the zebrafish (Danio rerio), the giant danio (D. malabaricus), and the pearl danio (D. albolineatus). The polymerase chain reaction was used to amplify and then sequence intron 1 and exon 2 of the class II B loci and exon 2 of the class II A loci in these species. Phylogenetic analysis of the sequences revealed the existence of allelic lineages whose divergence predates the divergence of the three species at both the A and B loci. The lineages at the B locus in particular are separated by large genetic distances. The polymorphism is concentrated in the peptide-binding region sites and is apparently maintained by balancing selection. Sharing of this unique Mhc feature by both bony fishes and mammals suggests that the main function of the Mhc (presentation of peptides to T lymphocytes) has not changed during the last 400 million years of its evolution.
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  • 2
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Cichlid fishes of the East African Rift Valley lakes constitute an important model of adaptive radiation. Explosive speciation in the Great Lakes, in some cases as recently as 12 400 years ago, generated large species flocks that have been the focus of evolutionary studies for some time. The studies have, however, been hampered by the paucity of biochemical markers for phylogenetic reconstruction. Here, we describe a set of markers which should help to alleviate this problem. They are the class I genes of the major histocompatibility complex. We provide evidence for the existence of at least 17 class I loci in cichlid fishes, and for extensive polymorphism of three of these loci. Since the polymorphism has a trans-species character, it will be possible to use it in investigating the founding events of the individual species. The sequences of the cichlid class I fishes support the monophyly of actinopterygian fish on the one hand, and of tetrapods on the other.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Immunogenetics 50 (1999), S. 116-123 
    ISSN: 1432-1211
    Keywords: Key words Histocompatibility ; Immunology ; Self-nonself discrimination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Traditional as well as biotechnological processing of coal leads to complex mixtures of products. Besides chemical and physical characterization, which provides the information for product application, there is a need for bioassays to monitor properties that are probably toxic, mutagenic or cancerogenic. Investigations carried out focused on the selection, adaptation and validation of bioassays for the sensitive estimation of toxic effects. Organisms like bacteria, Daphnia magna and Scenedesmus subspicatus, representing different complexities in the biosphere, were selected as test systems for ecotoxicological and mutagenicity studies. The results obtained indicate that bioassays are, in principle, suitable tools for characterization and evaluation of coal-derived substances and bioconversion products. Using coal products, coal-relevant model compounds and bioconversion products, data for risk assessment are presented.
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  • 5
    ISSN: 1432-0630
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 2 taken at low-temperature (4.2 K). This layered material is in a charge density wave (CDW) state below 35 K, with a period nearly commensurate to three times the atomic lattice. The CDW energy gap is 2Δ≈70 meV, but still the material remains metallic, even superconducting below 7.2 K. The bias-dependent phase shift in the STM image, in particular the comparison between occupied and unoccupied states, was shown to be attributable to the CDW, as no phase shift was observed in the atomic pattern. This phase shift does not result in a contrast reversal, which could be expected by analogy to some semi-conductor band gaps. The electron versus hole distribution has not been solved for a CDW gap, which is quite complex due to the many-band situation near the Fermi level. In the present work we write a general expression for the local density of states (LDOS) due to a commensurate CDW. Its amplitude and phase can be related in a simple way to the band structure, if one assumes an approximate form for the surface Bloch functions. We apply the method to the example of NbSe2, where its electronic structure is taken to be two-dimensional and the CDW is exactly commensurate to 3a. The new band structure and Fermi surface in the CDW state is calculated in perturbation theory, with a suitable pseudo-potential. The energy-dependent contrast is due to new states on the order of EF±Δ, having characteristic phases. The amplitude of the CDW is largest at the particular energies (or voltages) where tunneling occurs to the high symmetry points of the Brillouin zone. At these energies, the phase of the LDOS varies considerably, which gives a number of possible motifs in the STM image. For a shift in voltage corresponding to the energy gap edges, E=EF±Δ, we find that the maxima of the corrugation are shifted along the diagonal of the conventional unit cell.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 7
    ISSN: 1432-0932
    Keywords: Key words Scoliosis ; Scoliosis ; deformity ; Scoliosis ; vertebra ; Scoliosis ; rib ; Scoliosis ; biomechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although the structural changes occurring in the scoliotic spine have been reported as early as the 19th century, the descriptions and biomechanical explanations have not always been complete and consistent. In this study, three-dimensionally rendered CT images of two human skeletons with a scoliotic deformity and two patients with serious scoliosis were used to describe the intrinsic vertebral and rib deformities. The pattern of structural deformities was found to be consistent. Apart from the wedge deformation of the apical vertebrae, a rotation deformity was found in the transversal plane between the vertebral body and the posterior complex: the vertebral body was maximally rotated towards the convexity of the scoliotic curve, whereas the tip of the spinous process was pointed to posterior. The rib deformities at the convex side of the scoliotic curve showed an increased angulation of the rib at the posterior angle, whereas the rib curve on the concave side was flattened. The observed vertebral deformities suggest that these are caused by bone remodelling processes due to forces in the anterior spinal column, which drive the apical vertebral body out of the midline, whereas forces of the musculo-ligamentous structures at the posterior side of the spinal column attempt to minimize the deviations and rotations of the vertebrae. The demonstrated rib deformities suggest an adaptation to forces imposed by the scoliotic spine.
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  • 8
    ISSN: 1433-7347
    Keywords: Subjective outcome measure ; Patient questionnaire ; Visual analogue scale ; Knee surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Sports Science
    Description / Table of Contents: Zusammenfassung Bei der Erhebung von Patientendaten kommt der Patientenselbsteinschätzung neben klinischen Befunden eine zunehmende Bedeutung zu. Zu den relevanten subjektiven Daten bei verschiedenen Verletzungen des Kniegelenks werden neben spezifischen Symptomen wie Schmerzen und Schwellneigung Einschränkungen bei Alltagsbelastungen und bei sportlicher Aktivität gezählt. Die subjektiven Beschwerden können in Form eines standardisierten Fragebogens mit einer vereinfachten visuellen Analog-Skala (VAS) (Kästchenreihe mit 10 Kästchen) gut erfaßt werden. Es wurde überprüft, ob die deutsche Übersetzung eines englischsprachigen Knie-Fragebogens ein valides Instrument zur Beurteilung von Kapsel-Band-Verletzungen des Kniegelenkes darstellt. Der VAS-Fragebogen besteht aus 28 Fragen. Zur statistischen Auswertung wurde ein Gesamtscore des Fragebogens ermittelt (VAS-Score). Die Validierung umfaßte eine Expertenbefragung über die Struktur des Fragebogens, die Überprüfung der Reliabilität, den Vergleich mit anderen Score-Systemen (Cincinnati-Score, Lysholm-Score), und die Ermittlung von VAS-Score-Werten bei unterschiedlichen Kniegelenkserkrankungen und einer gesunden Kontrollgruppe. Zur Beurteilung operativer Behandlungsergebnisse wurde der VAS-Score im zeitlichen Verlauf vor und nach arthroskopischer Meniskusläsion und vorderer Kreuzbandersatzplastik ermittelt. Die Fragebogenerhebung erfolgte für beide Gruppen präoperativ, 2, 6, 12 und 24 Wochen postoperativ. Für die Kreuzbandpatienten wurde der VAS-Score zusätzlich 9 Monate postoperativ erhoben. Unter einer Gruppe von erfahrenen Kniechirurgen (n=41) (Expertengruppe) beurteilten 85% den VAS-Fragebogen als nützlich für die klinische Anwendung. Die Reliabilität des Fragebogens war bei Gesundenr=0,86 und bei Rehabilitations-Patientenr=0,92. Bei Patienten mit chronischen Kapsel-Band-Verletzungen (n=209) war die Korrelation zum Lysholm-Score und zum Cincinnati-Scorer=0,88 bzw.r=0,91. Durch den VAS-Score konnte das Ausmaß der Funktionseinschränkungen des Kniegelenkes bei verschiedenen Krankheitsbildern wie Meniskusläsionen, vorderen und hinteren Kreuzbandinsuffizienzen und Knorpelschäden gut abgebildet werden. Der VAS-Score war jedoch nicht krankheitsspezifisch für bestimmte Läsionen des Kniegelenkes. Im zeitlichen Verlauf wurden mit Hilfe des Scores Veränderungen des Funktionszustands nach arthroskopischer Meniskusoperation und nach vorderer Kreuzbandersatzplastik entsprechend dargestellt. Durch den Vergleich prä-und postoperativer Scorewerte konnte eine Beurteilung des Operationserfolges vorgenommen werden. Der VAS-Fragebogen ermöglicht die Erhebung subjektiver Patientendaten zeitsparend, ohne Beeinflussung durch den Untersucher und quantitativ auswertbar. Der Fragebogen kann als einfaches Instrument zur Evaluation und Qualitätskontrolle von operativen Therapiemaßnahmen (z. B. arthroskopischen Operationen) eingesetzt werden.
    Notes: Abstract Patients' complaints on limitations in activities of daily living (ADL) and sports are possible signs for various injuries of the knee joint. These complaints can be easily assessed by the patient using a questionnaire with visual analogue scale (VAS) responses. A German translation of the English questionnaire concerning knee complaints [4] has been validated and tested for clinical use. It consists of 28 questions. For the statistical analysis, an overall score (VAS score) of the questionnaire was determined. The validation included an expert evaluation on the content of the questionnaire, a test for the reliability, a comparison with subjective knee scoring systems (Cincinnati score, Lysholm score) and a test on VAS score results in patient groups with various knee injuries (discrimination of patients). For the evaluation of operative treatment results, the responsiveness of the questionnaire was tested in patients undergoing arthroscopic meniscus surgery and anterior cruciate ligament reconstruction. The investigation was conducted prior to the operation, 2, 6, 12 and 24 weeks after surgery for both groups and also 36 weeks after surgery for the cruciate ligament patients. Interviews conducted with knee surgeons (so-called knee experts) revealed that 85% judged the questionnaire as being acceptable for clinical use. The reliability of the VAS score for healthy individuals wasr=0.86. The reliability for patients in a postoperative rehabilitation programme wasr=0.92. The correlation coefficient for the Lysholm score wasr=0.88 and for the Cincinnati scorer=0.91. By means of the VAS score we were able to assess the extent of limitations in knee function in various patient groups with meniscus lesions, insufficiency of the anterior and posterior cruciate ligaments and chondromalacia. However, the VAS score was not specific for a single knee disorder. In patients who had undergone partial meniscal resection and anterior cruciate ligament (ACL) reconstruction, alterations in knee function could be adequately evaluated by means of the VAS score. When comparing the VAS score prior to and after the operation, an evaluation of the treatment result was possible. With such a questionnaire using the patient's VAS responses, subjective data can be assessed time-saving for the physician, without observer bias and submitted to statistical analysis. The questionnaire can be used as a simple and valid instrument for measuring the subjective outcome in knee surgery.
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  • 9
    ISSN: 1434-6036
    Keywords: PACS. 68.10.m Fluid surfaces and fluid fluid interfaces - 68.15.+e Liquid thin films - 68.45.Gd Wetting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The capillary broadening of a 2-phase interface is investigated both experimentally and theoretically. When a binary mixture in a thin film with thickness D segregates into two coexisting phases the interface between the two phases may form parallel to the substrate due to preferential surface attraction of one of the components. We show that the interfacial profile (of intrinsic width w0) is broadened due to capillary waves, which lead to fluctuations, of correlation length of the local interface positions in the directions parallel to the confining walls. We postulate that acts as an upper cutoff for the spectrum of capillary waves on the interface, so that the effective mean square interfacial width w varies as . In the limit of large D this yields or respectively for the case of short- or long-range forces between walls and the interface. We used the Nuclear Reaction Analysis depth profiling technique, to investigate this broadening effect directly in two binary polymer mixtures. Our results reveal that the interfacial width indeed increases with film thickness D, though the observed interfacial width is lower than the predicted w. This is probably due to surface tension effects imposed by the confining surfaces which are not taken into account in our model.
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  • 10
    ISSN: 1279-8517
    Keywords: Atlas bipartita ; Cleft atlas ; Fusion defect ; Klippel-Feil ; Cervical spine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A patient with the Klippel-Feil syndrome is described who presented with pain in the neck after a trauma. No fractures were found. Instead, a midline cleft in both the anterior and posterior atlantic arches was found which represents an extremely rare congenital anomaly.
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