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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 2513-2518 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ionized rare gas clusters Ar4+ and Xe4+ have been studied by photofragmentation. Center-of-mass velocities of the neutral and ionized photofragments have been measured for photon energies between 1.6 and 4.4 eV. In almost all of the examined photon energy region, both clusters exhibit fragment velocity distributions which show that they consist of a linear ionized trimer with an additional atom loosely attached to its side. For the lowest photon energies, however, fragmentation patterns are observed which can only be explained by a linear tetramer structure. This demonstrates that stable linear isomers of the ionized rare gas tetramers exist. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0630
    Keywords: PACS: 68.55.-a
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. A new development of the pulsed laser ablation (PLA) technique based on variable azimuth ablation (VAA) is reported. The VAA itself is based on periodic variations of the azimuth of the laser beam relative to the target at a constant angle of beam incidence. Such variations result in a suppression of cone–valley surface structures which tend to develop in the case of a fixed azimuth. VAA leads to high-level stabilization of the laser plume during a long-term deposition process. As a result, the VAA method stabilizes the deposition rate with a tolerance of only 3–6% instead of a 90% decrease in the rate as in conventional PLA. Different possibilities for the realization of the VAA technique based on 2- and 3-way target scans are discussed. In the case of large areas, VAA technique with a meander beam target scan is capable of the deposition of high-quality multicompositional superconducting films on tubes and tapes more than 1 m in length.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1433-0385
    Keywords: Key words: Colorectal carcinoma ; Outcome ; Quality management ; Ranking ; Surrogate endpoint. ; Schlüsselwörter: Ergebnisqualität ; Colorectales Carcinom ; Qualitätsmanagement ; Ranking ; Surregatendpunkt.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Anhand der Daten der prospektiven deutschen Multizenterstudie der Studiengruppe Kolorektales Karzinom (SGKRK) wurden die Klinikunterschiede im 5-Jahres-Überleben mit speziellen für ein sog. Ranking geeigneten biometrischen Methoden unter Wahrung der Anonymität analysiert. Weiterhin wurde nach sog. Surrogatendpunkten gesucht, die bereits früher als 5 Jahre nach Ersttherapie eine Aussage über die Ergebnisqualität der chirurgischen Therapie ermöglichen. Hierzu ist eine gesonderte Analyse für Rectum- und Coloncarcinompatienten erforderlich. Für das Rectumcarcinom ist die Kombination von Häufigkeit örtlicher Tumorzelldissemination bei Tumorresektion (intraoperativer Einriß im Tumor und/oder Schnitt in oder durch Tumorgewebe) und Rate locoregionärer Rezidive (innerhalb von 2 Jahren) nach Operation als verläßlicher Surrogatendpunkt anzusehen. Beim Coloncarcinom konnte ein solcher nicht gefunden werden. Die postoperative Morbidität ist als Indikator für die definitive Ergebnisqualität ungeeignet. Eine sehr niedrige Rate postoperativer Todesfälle bietet keine Gewähr auf zufriedenstellende Langzeitergebnisse in der colorectalen Carcinomchirurgie.
    Notes: Summary. The data of the German Prospective Multicenter Study of the Study Group Colorectal Carcinoma (SGCRC) were analyzed with regard to interinstitutional differences in 5-year survival by statistical methods adequate for ranking and observing anonymity. Furthermore, possible so-called surrogate endpoints that allow an assessment of definite outcome after surgical treatment earlier than after 5 years were also analyzed. This requires a separate analysis for rectal and colon carcinoma patients. For rectal carcinoma, the combination of the frequency of local tumor cell spillage during tumor resection (iatrogenous tumor perforation and/or incision into or through tumor tissue) and the rate of locoregional recurrences (within 2 years after surgery) could be demonstrated as realiable surrogate endpoint. For colon carcinoma, no reliable surrogate endpoint could be found. Surgical morbidity is not an indicator of definite outcome. A very low rate of surgical mortality does not ensure satisfactory long-term results in colorectal cancer surgery.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1433-0458
    Keywords: Schlüsselwörter TNM-Klassifikation (4. Aufl.) ; TNM-Klassifikation (5. Aufl.) ; UICC ; Kopf- und Halstumoren ; Tumorstaging ; Key words TNM classification (4th edition) ; TNM classification (5th edition) ; Head and neck cancer ; Tumor staging ; UICC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The 5th edition of the TNM classification entails a number of changes concerning head and neck tumors. The division of stage IV tumors into three subcategories marks a significant expansion of the stage grouping procedure. Methods: In a retrospective study the clinical course of 3247 patients with head and neck carcinomas were comparatively evaluated according to the 4th and 5th editions of the new TNM classification. In particular it was the aim of the study to test the prognostic relevance of the subdivision of stage IV especially in mucosal cancer. Results: In classifying the primary tumor the most extensive changes were noted for supraglottic and salivary gland tumors. On the basis of the 4th edition of the TNM classification the following recurrence-free 5-year survival rates for 3033 cases of mucosal cancer were calculated: stage I 91,0%, stage II 78,6%, stage III 61,4%, stage IV 31,0%. The calculations based on the 5th edition yielded: stage I 91,0%, stage II 77,2%, stage III 61,2%, stage IVA 32,4%, stage IVB 25,3%, stage IVC 3,6%. Conclusions: The adequacy of the revised stage classification in establishing a prognostic hierarchy was confirmed. However, a significant prognostic distinction between N2- (stage IVA) and N3-metastasis (stage IVB) could not be found.
    Notes: Zusammenfassung Die 5. Aufl. der TNM-Klassifikation bringt einige Änderungen im Bereich der Kopf-Hals-Tumoren mit sich. Eine wesentliche Erweiterung der Stadiengruppierung besteht in der Unterteilung von Stadium IV in 3 Unterstadien. In einer retrospektiven Studie wurden die Krankheitsverläufe von 3247 Patienten mit Karzinomen der Mundhöhle, des Oro- und Hypopharynx, des Larynx, der Speicheldrüsen und der Kieferhöhle ausgewertet. Hierbei kamen die 4. und die 5. Aufl. der TNM-Klassifikation vergleichend zur Anwendung. Insbesondere wurde geprüft, ob der Unterteilung von Stadium IV eine prognostische Relevanz zukommt. Bei der Klassifikation des Primärtumors ergaben sich die umfassendsten Änderungen bei Tumoren der Supraglottis und der Speicheldrüsen. Nach der 4. Aufl. der TNM-Klassifikation errechneten sich folgende rezidivfreien Fünfjahresüberlebensraten: Stadium I 89,7%, Stadium II 78,9%, Stadium III 60,3%, Stadium IV 31,0%, nach der 5. Aufl.: Stadium I 90,8%, Stadium II 77,1%, Stadium III 61,3%, Stadium IVA 32,2%, Stadium IVB 25,8%, Stadium IVC 7,9%. Die Eignung der neuen Stadieneinteilung zur Schaffung einer prognostische Hierarchie konnte bestätigt werden. Allerdings ließ sich kein signifikanter Prognoseunterschied zwischen einer N2- (Stadium IVA) und einer N3-Metastasierung (Stadium IVB) finden.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1433-0385
    Keywords: Key words: Colorectal carcinoma ; Operative technique ; Recurrence rate ; Five-year survival rate. ; Schlüsselwörter: Colorectale Carcinome ; Operationsmethodik ; Rezidivrate ; 5-Jahres-Überlebensrate.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Einleitung: Um zu prüfen, ob die Operationsmethodik die 5-Jahres-Rezidivrate und -Überlebensrate bestimmt, haben wir die Ergebnisse von 2 chirurgischen Kliniken mit unterschiedlicher Operationsmethodik (Klinik A: Entfernung des Tumors und der tumornahen Lymphknoten, Klinik B: En bloc-Resektion nach den Regeln der standardisierten Tumorchirurgie) analysiert. Patienten und Methoden: Analyse der Operationsergebnisse aller zwischen 1984–1988 operierten Patienten mit colorectalem Carcinom (Klinik A: 152 Colon- und 53 Rectumcarcinome; Klinik B: 124 Colon- bzw. 177 Rectumcarcinome). Ergebnisse: Die Lokalrezidivraten bei Klinik A signifikant höher (Coloncarcinome Klinik A 25 %, Klinik B 10 %; Rectumcarcinome Klinik A 54 %, Klinik B 16 %. Die 5-Jahres-Überlebensrate betrug bei den Coloncarcinomen in Klinik A 65 %, in Klinik B 66 %, bei den Rectumcarcinomen in Klinik A 49 %, in Klinik B 72 %. Schlußfolgerungen: Aus dieser Analyse läßt sich ableiten, daß ein colorectales Carcinom nur dort operiert werden sollte, wo die Standards der colorectalen Carcinomchirurgie eingehalten werden.
    Notes: Summary. Introduction: In order to investigate whether operative technique determines the 5-year recurrence and survival rates, we analysed the results obtained by two surgical departments using two different operative techniques. Department A: Removal of the tumour and a number of lymph nodes; department B: En-bloc resection in accordance with the requirements of standardised tumour surgery. Patients and methods: The surgical results obtained with all patients with colorectal carcinoma operated on between 1984 and 1988 (department A: 152 colon and 53 rectal carcinomas; department B: 124 colon and 177 rectal carcinomas). Results: The local recurrence rate achieved by department A was signicantly higher (colon carcinoma: department A 25 %; department B 10 %; rectal carcinoma: department A 54 %; department B 16 %). The 5-year survival rate for colon carcinoma was 65 % in department A, and 66 % in department B, the corresponding figures for rectal carcinoma being 49 % and 72 %, respectively. Conclusion: The results indicate that carcinoma of the colorectum should be operated on only at an institution that complies with the standards required for surgery of colorectal carcinoma.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1617-4623
    Keywords: Key words Gene disruption ; Gene targeting ; Homologous recombination ; Plant transformation ; Physcomitrella patens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The analysis of phenotypic change resulting from gene disruption following homologous recombination provides a powerful technique for the study of gene function. This technique has so far been difficult to apply to plants because the frequency of gene disruption following transformation with constructs containing DNA homologous to genomic sequences is low (0.01 to 0.1%). It has recently been shown that high rates of gene disruption (up to 90%) can be achieved in the moss Physcomitrella patens using genomic sequences of unknown function. We have used this system to examine the specificity of gene disruption in Physcomitrella using a member of the Cab multigene family. We have employed the previously characterised Cab gene ZLAB1 and have isolated segments of 13 other closely related members of the Cab gene family. In the 199-bp stretch sequenced, the 13 new members of the Cab family show an average of 8.5% divergence from the DNA sequence of ZLAB1. We observed 304 silent substitutions and 16 substitutions that lead to a change in the amino acid sequence of the protein. We cloned 1029 bp of the coding region of ZLAB1 (including 177 of the 199 bp with high homology to the 13 new Cab genes) into a vector containing a selectable hygromycin resistance marker, and used this construct to transform P. patens. In three of nine stable transformants tested, the construct had inserted in, and disrupted, the ZLAB1 gene. There was no discernible phenotype associated with the disruption. We have therefore shown that gene disruption is reproducible in P. patens and that the requirement for sequence homology appears to be stringent, therefore allowing the role of individual members of a gene family to be analysed in land plants for the first time.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 190 (1999), S. 267-293 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We analyze radio observations, magnetograms and extrapolated field line maps, Hα filtergrams, and X-ray observations of two flare events (6 February 1992 in AR 7042 and 25 October 1994 in AR 7792) and study properties, evolution and energy release signatures of sigmoidal loop systems. During both events, the loop configuration seen in soft X-ray (SXR) images changes from a preflare sigmoidal shape to a relaxed post-flare loop system. The underlying magnetic field system consists of a quadrupolar configuration formed by a sheared arcade core and a remote field concentration. We demonstrate two possibilities: a sigmoidal SXR pattern can be due to a single continuous flux tube (the 1992 event). Alternatively, it can be due to a set of independent loops appearing like a sigmoid (the 1994 event). In both cases, the preflare and post-flare loops can be well reproduced by a linear force-free field and potential field, respectively, computed using preflare magnetograms. We find that thermal and non-thermal flare energy release indicators of both events become remarkably similar after applying spatial and temporal scale transformations. Using the spatial scaling between both events we estimated that the non-thermal energy release in the second event liberated about 1.7 times more energy per unit volume. A two-and-a-half times faster evolution indicates that the rate of the energy release per unit volume is more than four times higher in this event. A coronal type II burst reveals ignition and propagation of a coronal shock wave. In contrast, the first event, which was larger and released about a 10 times more energy during the non-thermal phase, was associated with a CME, but no type II burst was recorded. During both events, in addition to the two-ribbon flare process an interaction was observed between the flaring arcade and an emerging magnetic flux region of opposite polarity next to the dominant leading sunspot. The arcade flare seems to stimulate the reconnection process in an `emerging flux-type' configuration, which significantly contributes to the energy release. This regime is characterized by the quasiperiodic injection of electron beams into the surrounding extended field line systems. The repeated beam injections excite pulsating broadband radio emission in the decimetric-metric wavelength range. Each radio pulse is due to a new electron beam injection. The pulsation period (seconds) reflects the spatial scale of the emerging flux-type field configuration. Since broadband decimetric-metric radio pulsations are a frequent radio flare phenomenon, we speculate that opposite-polarity small-scale flux intrusions located in the vicinity of strong field regions may be an essential component of the energy release process in dynamic flares.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Langenbeck's archives of surgery 384 (1999), S. 313-327 
    ISSN: 1435-2451
    Keywords: Key words Colorectal cancer ; Liver metastases ; Surgery ; Long-term results ; Technical aspects ; Prognostic factorsIntroduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Introduction: Surgical resection is presently the only approach that offers patients with liver metastases from colorectal carcinoma substantial chance of cure. This article summarizes the current literature as well as the author’s personal experience. Background and discussion: Since 1980, 5-year survival figures have ranged from 21% in collected series to 48% in single-institution series. The 30-day mortality of elective liver resection in non-cirrhotic patients ranges now between 0% and 5%. The overwhelming indicator of prognosis is the completeness of tumor removal according to the R-classification. The specific impact of all other factors should therefore be analyzed by excluding non-radical procedures and operative mortality. Among patient characteristics, age and gender do not significantly affect outcome, while the Karnofski stage is important. Regarding the primary tumor, the effect of staging and location is predominantly apparent in patients with synchronous metastases. Timing of metastasis detection is of some importance, as most authors found a slightly better outcome for metachronously detected metastases. With respect to the liver involvement, multiplicity of metastases and bilateral disease both seem to be of minor importance after R0-resection, while satellite lesions are significant in many series. The actual number of metastases is of minor effect, with a slight superiority in 5-year survival for patients with one to three nodules relative to patients with four nodules or more in most series, but identical results in the author’s own experience. The maximum diameter as an indicator of tumor burden represents a significant prognosticator in half of the reports analyzed. Extrahepatic disease reduces 5-year survival, but direct tumor invasion to adjacent structures, local recurrent disease, or one or few pulmonary metastases are no contraindication to liver resection as long as a R0-situation can be achieved. In contrast, lymph-node metastases at the liver hilum predict a poor outcome. They are likely to prove as a clear contraindication. With respect to the operative approach, a clear margin of 1 cm or more should be aimed at but, if the size or location of metastases do not allow a 1-cm margin, resection should still be performed, making every surgical effort to ensure a complete rim of unaffected tissue. Anatomic resections reduce the incidence of non-radical procedures and may improve survival. Whether there is an independent effect of operative blood loss, need for blood transfusion, and intraoperative hypotension on prognosis is still unclear. Adjuvant chemotherapy or radiotherapy after R0-resection is unlikely to improve results. There are also no convincing data available demonstrating a prognostic benefit when a non-curative resection is supplemented by any medical treatment. In patients with recurrent disease, a re-resection is possible in roughly 20%. Survival from the time of re-intervention ranges from 21% to 57% after 5 years and, thus, justifies a close follow-up policy after R0-resection of the initial liver metastases. Conclusion: The previous ”clear” contraindications to liver resection have become less important. Future efforts may be directed to more accurate patient selection and new approaches of neoadjuvant and adjuvant therapeutic strategies.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Hyperfine interactions 120-121 (1999), S. 253-256 
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We performed 57Fe Mössbauer spectroscopy on differently substituted ferrocenium salts. The spectra exhibit a temperature dependent non-Lorentzian absorption line due to fast paramagnetic relaxation processes. χ2 fits using a two-level stochastic fluctuation theory revealed an activated temperature behaviour of the relaxation rate interpreted in terms of an Orbach process.
    Type of Medium: Electronic Resource
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