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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Rheumatologie 57 (1998), S. 139-146 
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Rheumatoide Arthritis ; Gentherapie ; Definition der Gentherapie ; Vektorsysteme ; tierexperimentelle Versuche ; erste Ansätze bei RA Patienten ; Key words Rheumatoid arthritis ; gene therapy ; experimental animal models ; ex vivo and ex vitro experiments ; vector systems ; first trials in RA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Based upon our increasing knowledge of mechanisms underlying tissue destruction in RA patients, new therapeutic principles have been developed, aimed at blocking proinflammatory cytokines or using antiinflammatory cytokines. Both principles, however, have proven to be very effective. In addition, the availability of the methodology to transduce cells with genes has initiated first experiments in animal models to test whether gene therapy for arthritis is suitable, followed by a first, very carefully formulated protocol for human RA. Gene therapy for RA has to still be considered as an experimental form of therapy in a very early stage, not allowing even now any serious treatment offer to RA patients. Several problems, such as the question of a suitable vector system have not yet been solved. With more experiments this therapeutic principle might become available and might prove effective even in a disease with a systemic character like RA in the coming years.
    Notes: Zusammenfassung Mit einem zunehmenden Kentnisstand über pathogenetische Mechanismen, die bei der rheumatoiden Arthritis zu einer Gelenkdestruktion führen, haben sich neue Therapieprinzipien entwickeln lassen, die durch eine Blockade von proinflammatorischen Zytokinen oder der Anwendung von antiinflammatorischen Zytokinen den Krankheitsverlauf zum Teil außerordentlich günstig beeinflussen. Mit den zusätzlichen Möglichkeiten, Gene für antiinflammatorische Therapieprinzipien wie den Interleukin 1 Rezeptorantagonisten in Zellen einzubringen, sind auch erste Versuche, basierend auf vorangegangenen Experimenten im Versuchstier, bei Patienten mit einer RA vorgenommen worden, mit dem Ziel die Krankheitsaktivität durch die intraartikuläre Injektion von transduzierten autologen Zellen zu behandeln. Die ersten Versuche sind ermutigend, doch ist es zu früh, dieses Therapieprinzip als eine Behandlungsmethode für die rheumatoide Arthritis anzubieten. Weitere Untersuchungen, nicht zuletzt hinsichtlich der Bereitstellung besserer Vektoren sind notwendig, um eine Gentherapie der rheumatoiden Arthritis zu realisieren.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Rheumatologie 57 (1998), S. 147-158 
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Chronische Polyarthritis ; Halswirbelsäule ; okzipitozervikale Fusion ; transorale Densresektion ; Key words Rheumatoid arthritis ; cervical spine ; occipitocervical fusion ; transoral dens resection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary This report will relate our experience with the y-plate, which we used in the treatment of 39 patients (32 women and 7 men) with a mean age of 62.6 years (range 47 to 79 years) between 1987 and 1994. All patients had rheumatoid arthritis. Occipitocervical fusion was indicated by instabilities within the occipitocervical region and in cases with additional basilar invagination and/or after transoral dens resection for decompression of the spinal cord. The length of the fusion depended on the pathological changes of the subaxial cervical spine. Before surgery, 35 patients suffered from strong and 4 patients from moderate pain in the neck and/or the back of the head. On a linear scale from 0 to 10, the pain was rated as 8.1 on average (range 4 to 10). 31 patients had an instability of the atlantoaxial region and 19 patients a basilar invagination of the odontoid. A cervical myelopathy was found in 20 cases. One surgeon fused the occiput to C2 in 22 cases, to C3–C5 in 8 cases and to C7–T2 in 9 cases. An important factor in this operation is the integration of atlantoaxial screws in order to resist the translational dislocation of C1/C2. In 13 patients a resection of the odontoid had to be performed to adequately decompress the spinal cord. A reduction of C2 without dens resection was performed in cases with reducible instability C1/2. 32 of the patients could be controlled with a minimum follow-up of 12 months (average 32.2 months, range 12 to 66 months). Out of the other 7, 6 patients had died. At the time of follow-up, the pain was rated as 2.3 on average (range 0 to 10). A myelopathy was present in 2 cases. Six patients required further operations on the cervical spine; 4 patients developed an instability at the level(s) below the fusion and an enlargement of the fusion to these levels had been performed. The fusion rate was 96.9%, despite breakage of the implant in 3 and a screw loosening in 2 patients. According to the criteria of Conaty, the result was satisfying in 25 (75%) and not satisfying in 8 patients (25%). These results show the effectiveness of the occipitocervical fusion with the y-plate in rheumatoid arthritis. A transoral dens resection is only indicated in cases with basilar invagination causing a compression of the spinal cord or in such cases where a compression caused by the dens or the retrodental pannus formation cannot be treated by a reduction of the second cervical vertebra alone.
    Notes: Zusammenfassung Zielsetzung: In einer retrospektiven Studie untersuchten wir die Ergebnisse der okzipitozervikalen Fusion mit der Y-Platte bei 39 Patienten (32 Frauen und 7 Männer) mit chronischer Polyarthritis, die zwischen 1987 und 1994 an der Schulthess-Klinik Zürich mit einem Durchschnittsalter von 62,6 Jahren (47 bis 79 Jahre) operiert wurden. Die Indikation zum chirurgischen Eingriff wurde bei Instabilität des okzipitozervikalen Übergangs und in Fällen mit basilärer Impression und/oder nach transoraler Densresektion gestellt, wobei die Ausdehnung der Fusion vom Ausmaß der pathologischen Veränderungen der mittleren und unteren Halswirbelsäule abhing. Material: Präoperativ klagten 35 Patienten über starke und 4 über mittelstarke Schmerzen im Nacken und/oder Hinterkopf, die auf einer linearen Skala von 0 bis 10 mit durchschnittlich 8,1 (4 bis 10) beurteilt wurden. Bei 31 Patienten war eine atlantoaxiale Instabilität und bei 19 Patienten eine basiläre Impression des Dens in das Foramen magnum vorhanden. Eine zervikale Myelopathie wurde in 20 Fällen diagnostiziert. Die Fusion erfolgte vom Occiput bis C2 in 22, bis C3–C5 in 8 und bis C7–Th2 in 9 Fällen. Bei 13 Patienten wurde vor der dorsalen Stabilisierung eine transorale Densresektion durchgeführt. Ergebnisse: 32 Patienten konnten mit einem Mindestzeitraum von 12 Monaten (durchschnittlich 32,2 Monate, Minimum 12 Monate, Maximum 66 Monate) nachkontrolliert werden. Nach den Kriterien von Conaty wurde in 24 Fällen (75%) ein befriedigendes und in 8 Fällen (25%) ein unbefriedigendes Resultat erzielt. Zum Nachkontrollzeitpunkt wurde der Schmerz mit durchschnittlich 2,3 (0 bis 10) angegeben. Eine Myelopathie war bei 2 Patienten vorhanden. Bei 6 Patienten wurden weitere Operationen an der Halswirbelsäule nötig. Bei 4 Patienten mußte die Fusion nach kaudal verlängert werden, da eine Instabilität in den Segmenten unterhalb der Spondylodese aufgetreten war. Die Fusionsrate betrug 96,9%, obwohl es bei 3 Patienten zu einem Plattenbruch und bei 2 zu einer Schraubenlockerung gekommen war. Schlußfolgerung: Die Ergebnisse zeigen die Effektivität der okzipitozervikalen Fusion bei Patienten mit chronischer Polyarthritis. Eine transorale Dekompression halten wir nur bei den Fällen für indiziert, in denen eine durch den Dens axis oder das retrodentale Pannusgewebe hervorgerufene Kompression des Myelons nicht durch eine Extension behoben werden kann oder in denen eine basiläre Impression mit Myelonkompression vorliegt.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Katzenkratzkrankheit ; reaktive Spondarthritis ; Bartonella henselae ; rheumatische Manifestationen ; Key words ; Rheumatic manifestations ; reactive spondylarthropathy ; cat scratch disease ; Bartonella henselae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Cat scratch disease (CSD) is a rarely recognized infectious disease in Germany. Only a few years ago the causative agent, Bartonella henselae, could be isolated. The typical clinical manifestations of CSD consist of skin changes at the inoculation site and a benign lymphadenopathy; other manifestations are rare. We report the case of a 47 year old woman, who developed a reactive spondylarthropathy with synovitis of finger joints, polyarthralgias of large- and medium-sized joints, and inflammatory spinal pain after a cat bite. The rheumatic manifestations resolved after 10 months by treatment with non-steroidal antirheumatic drugs. Only a few cases of rheumatic manifestations associated with CSD have been described in the literature. Because the prevalence of Bartonella henselae infection of cats is high in Europe, rheumatic manifestations might be more frequent. Diagnosis of CSD is now improved by the development of serological tests. We provide an overview of the clinical manifestations and the diagnostic criteria.
    Notes: Zusammenfassung Bei der Katzenkratzkrankheit (KKK) handelt es sich um eine in Deutschland wenig bekannte Infektionskrankheit. Erst vor wenigen Jahren konnte der Erreger, Bartonella henselae, isoliert werden. In der Mehrzahl der Fälle findet sich ein typisches Krankheitsbild mit Hautveränderungen im Bereich von Katzenbiß- oder Kratzwunden und einer benignen Lymphadenopathie. Weniger häufig kommt es zu weiteren Organmanifestationen. Wir berichten über eine 47-jährige Patientin, die nach einem Katzenbiß eine reaktive Spondarthritis mit Synovialitiden der Fingergelenke, Polyarthralgien der mittleren und großen Gelenke und entzündliche Lumbalgien entwickelte. Die rheumatische Symptomatik war zeitlich limitiert und sprach gut auf NSAR an. Bislang sind nur wenige Fälle von Gelenkbeteiligung im Rahmen einer KKK beschrieben worden. Da die Durchseuchung von Katzen mit Bartonella henselae in Europa jedoch hoch ist, könnte es sich um eine häufigere Ursache von Gelenkbeschwerden handeln, als bislang angenommen. Die Diagnostik der KKK wurde in den letzten Jahren durch die Entwicklung serologischer Teste erleichtert. Wir geben einen Überblick über die klinischen Manifestationen und fassen die diagnostischen Kriterien dieser Erkrankung zusammen.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Chronische Polyarthritis ; Tumornekrosefaktorα ; Rezeptor-Fusionprotein ; TNFR-IgG ; Key words Rheumatoid arthritis ; tumor necrosis factorα ; receptor fusion protein ; TNFR-IgG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Aim of studies: To determine the optimal dose regimen for i.v. TNFR55-IgG1 in refractory rheumatoid arthritis. Methods: 218 patients with refractory rheumatoid arthritis were enrolled for two double-blind placebo-controlled multicenter trials (Europe and USA). They were treated with monthly i.v. placebo, 0.01, 0.05, 0.1 or 0.5mg/kg TNFR55-IgG1 after a 4 week wash-out of DMARDs. An additional German trial compared biweekly i.v. 20mg TNFR55-IgG1 and monthly 50mg following a loading does of 100mg in 60 patients. Results: TNFR55-IgG1 induced a substantial improvement already apparent one day after the first infusion. A maximal, dose dependent effect was reached after two weeks. Later, efficacy declined in parallel to an increase in anti-TNFR55-IgG1 antibodies resulting in an increased drug clearance. The drug was well tolerated with predominantly mild or moderate adverse events. Conclusion: Intravenous TNFR55-IgG1 was well tolerated and effective in refractory rheumatoid arthritis but the treatment schedules tested could not stabilise the initial improvement.
    Notes: Zusammenfassung Ziel der folgenden Studien war die Dosisoptimierung für eine Therapie der chronischen Polyarthritis mit TNFR55-IgG1 durch Erfassung der Wirksamkeit, Sicherheit, Verträglichkeit und Pharmakokinetik. Methode: In zwei doppelblinden, placebokontrollierten, multizentrischen Studien (Europa und USA) wurden insgesamt 218 Patienten mit refraktärer, florider chronischer Polyarthritis nach Auswaschen der Basistherapeutika bei gleichbleibender Dosis von NSAR und ggf. Steroiden mit monatlich i.v. Placebo, 0,01, 0,05, 0,2 oder 0,5mg/kg TNFR55-IgG1 behandelt. In einer weiteren deutschen Studie wurde eine Erhaltungstherapie von 14tätig 20mg TNFR55-IgG1 i.v. verglichen mit einer monatlichen Gabe von 50mg. Zuvor hatten die 60 Patienten in dieser Studie eine initale Dosis von 100mg erhalten. Ergebnis: In allen drei Studien zeigten Patienten, die mit TNFR55-IgG1 behandelt wurden, eine rasche und deutlische Besserung aller gemessenen Parameter bereits einen Tag nach der ersten Gabe. Das Maximum des therapeutischen Effektes war von der Dosis abhängig und wurde nach zwei Wochen erreicht. Nachfolgend kam es trotz der weiteren Gabe der Prüfsubstanz zu einem Anstieg der Entzündungsparameter. Parallel konnten anti-TNFR55-IgG1 Antikörper nachgewiesen werden, die die Clearance der Prüfsubstanz beschleunigten. Die Prüfsubstanz wurde in den drei Studien gut vertragen. Diskussion: Intravenöses TNFR55-IgG1 war rasch wirksam und gut verträglich bei Patienten mit „therapierefraktärer” chronischer Polyarthritis. Mit den geprüften Therapieschemata konnte aber die initial erreichte Besserung nicht aufrecht erhalten werden.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Rheumatologie 57 (1998), S. 351-354 
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Qualitätsmanagement ; Fortbildung ; Key words Quality management ; further education
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Since 1996, the curriculum „Quality management for physicians” exists with a three-level training concept. Based on these contents, a purposeful course program has been developed by the ZQ, and through May 1998 four level I-, four level II- and four level III-courses have been performed in Hannover. Thus, 50 physicians are qualified for new professional roles as hospital quality managers. The evaluation of a standardized questionnaire shows that the concept is highly accepted – meanwhile also by other professionals in health care. As a new model of quality assurance/quality evaluation is now developed for German hospitals, the contents of the training program will be updated for actual needs.
    Notes: Zusammenfassung Mit dem Curriculum „Ärztliches Qualitätsmanagement” liegt seit 1996 ein dreistufiges Fortbildungkonzept vor. Gemäß dem auf dieser Basis entwickelten zielorientierten Kursangebot wurden bisher im ZQ vier Grundkurse, vier Stufe-II-Kurse und vier Stufe-III-Kurse durchgeführt. Damit sind inzwischen 50 Ärzte/innen für neue Rollen als Qualitätsmanager im Krankenhaus qualifiziert. Die Ergebnisse der Teilnehmerbefragungen zeigen, daß das Konzept positiv bewertet wird – inzwischen auch von anderen Berufsgruppen im Gesundheitswesen. Nach nunmehr zweijähriger Erfahrung steht eine Aktualisierung der Inhalte bevor, insbesondere vor dem Hintergrund neuer anstehender Qualitätsdarlegungsmodelle für deutsche Krankenhäuser.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Rheumatologie 57 (1998), S. 345-350 
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Qualitätssicherung ; Qualitätsmanagement ; Patientenzufriedenheit ; Prozeßqualität ; Rehabilitation ; Key words Quality management ; process quality ; benchmarking ; patient satisfaction ; rehabilitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In the context of the quality assurance program of the German pension insurance institutions, instruments and procedures have been developed in the past few years in order to assess the quality of structure, process, and results of inpatient rehabilitation, as well as patient satisfaction. The routine implementation of these procedures aims at providing rehabilitation hospitals with fast information on shortcomings in their current practice, so that concepts of treatment and – in the long run – effects of rehabilitation can be systematically improved. When the „quality profiles” of rehabilitation hospitals are compared („benchmarking”), paying institutions of rehabilitation could gain information on the cost-quality-ratio of particular hospitals as well as important leads for improving the steering processes of patients and hospitals.  In the present article, results of a first „field-run” of the procedures for measuring patient satisfaction and quality of rehabilitation processes are reported. A comparative analysis of patient satisfaction in four orthopaedic/rheumatologic rehabilitation hospitals showed high degrees of overall satisfaction in all hospitals. In several subdimensions of patient satisfaction, however, significant differences between hospitals were found.  Quality of rehabilitation processes – as assessed by a standardized peer-review – varied substantially between 36 hospitals. Problems of quality were found especially in some dimensions that must be considered as crucial for rehabilitation, e.g., in the history and diagnosis of disabilities, in the consideration of psycho-social problems, or in the assessment of occupational capacities.
    Notes: Zusammenfassung Im Rahmen des Qualitätssicherungsprogramms der Rentenversicherungsträger wurden in den letzten Jahren Instrumente und Verfahren zur Erfassung der Struktur-, Prozeß- und Ergebnisqualität sowie der Patientenzufriedenheit erarbeitet. Durch den routinemäßigen Einsatz dieser Verfahren sollen den Kliniken zeitnah Informationen über etwaige Qualitätsprobleme („Schwachstellen”) zur Verfügung gestellt werden, die eine Weiterentwicklung der Behandlungskonzepte und damit letztlich bessere Rehabilitationsergebnisse ermöglichen sollen. Ein Vergleich der Qualitätsprofile von Rehabilitationseinrichtungen („benchmarking”) kann den Kostenträgern der Rehabilitationsmaßnahmen – neben wirtschaftlichen Gesichtspunkten (Pflegesatz) – außerdem wichtige Hinweise für die Zuweisungs- und Belegungssteuerung liefern. In der vorliegenden Arbeit werden Ergebnisse aus einem ersten Einsatz der Verfahren zur Messung von Patientenzufriedenheit und zur standardisierten Beurteilung der Prozeßqualität vorgestellt.  Bei einer vergleichenden Analyse der Patientenzufriedenheit in vier Rehabilitationskliniken mit orthopädisch/rheumatologischem Schwerpunkt fanden wir insgesamt eine hohe Zufriedenheit mit den Rehabilitationsmaßnahmen. In einigen Bereichen der Zufriedenheit ergaben sich zwischen den Kliniken jedoch signifikante Unterschiede.  Die Prozeßqualität, beurteilt durch ein Peer-Review-Verfahren, variiert zwischen 36 untersuchten Kliniken erheblich. Qualitätsprobleme fanden sich insbesondere in einigen für die Rehabilitation zentralen Dimensionen, so z.B. bei der Anamnese und Diagnostik von Fähigkeits- und Funktionsstörungen, bei der Berücksichtigung psychosozialer Belastungen und bei der sozialmedizinischen Stellungnahme.
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  • 7
    ISSN: 0340-1855
    Keywords: Schlüsselwörter ; Knorpelmatrixstruktur ; Enzyme ; Knorpelmarker ; Aggrecan-Fragmente ; Keratansulfat ; Chondroitinsulfat ; Hyaluronsäure ; Prokollagen ; crosslinks ; COMP ; Key words ; Extracellular cartilage matrix ; enzymes ; cartilage markers ; aggrecan ; hyaluronan ; keratan sulphat ; chondroitin sulphate ; procollagen ; crosslinks ; COMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The human cartilage and bone is characterized by a remodeling during the life, well balanced by neosynthesis and degradation of matrix components. In different joint diseases, it becomes imbalanced and the destruction of the cartilage supersedes the repair. In tissue processes in disease and in normal turnover of the matrix, these molecules are fragmented and released into surrounding fluids, in the synovial fluid, and then in the blood and the urin, where they can be detected. The quantitative measurement in the synovial fluid is more specific than in the other body fluids.  The research process in recent years has suggested that these molecular markers of cartilage and bone matrix metabolism can be used to determine diagnosis, the disease severity rather than its presence or absence, the prognosis, and the response to therapy. They should help to identify the disease mechanism in different joint diseases not only on the tissue but also on the molecular level. The specific cartilage matrix markers promise to become useful tools in the future in clinical use. The research in this area is still in the early stages, with most results dated from the end of the 1980s and the 1990s.
    Notes: Zusammenfassung Während des Lebens unterziehen sich Knorpel und Knochen in Anpassung an sich verändernde Belastungsbedingungen einem „Remodelling“, welches normalerweise ein physiologisches Gleichgewicht zwischen Abbau und Neusynthese von Matrixkomponenten darstellt. Bei differenten Gelenkerkrankungen ist dieses Gleichgewicht zugunsten der Destruktion verschoben. Beim normalen „turnover“ und gesteigert unter pathologischen Gelenkverhältnissen können intakte und framentierte Matrixbestandteile in die Synovialflüssigkeit, in das Blut und den Urin austreten und dort nachgewiesen werden. Eine Messung von Markern in der Synovia hat eine höhere Gelenkspezifität, während Serum-, Plasma- oder Urinmessungen eher den systemischen Stoffwechsel reflektieren. Der Forschungsprozeß der letzten Jahre hat die Hoffnung bestärkt, eventuell durch kombinierte Messungen mehrerer biochemischer Marker der Synthese und Destruktion des Knorpels und Knochens einen frühen diagnostischen Zugang, eine vermehrte prognostische Aussagefähigkeit und eine Hilfe in der Therapiekontrolle zu erhalten. Durch diese Markerstudien kann ein Beitrag zum besseren Verständnis des Knorpelmetabolismus und des Krankheitsmechanismus auf dem Gewebs- und Zellniveau geleistet werden. Es besteht die Notwendigkeit einer intensiven Forschung auf dem Gebiet der biochemischen Markersuche zur Nutzung im Bereich der Frühdiagnostik, der Verlaufsbeurteilung, der Kontrolle der Entzündungsaktivität sowie der Therapie- und Rehabilitationseffizienz bei degenerativen, traumatischen und entzündlichen Gelenkerkrankungen, woran weltweit gearbeitet wird. Mit der Anwendung von biochemischen Markern würde besonders die klinische Prüfung verschiedener Therapieformen auf eine solidere Basis gestellt.  Die gewebsspezifischen Marker des Knorpelmetabolismus versprechen in Zukunft nützliche Werkzeuge in der klinischen Anwendung zu werden, mit weiteren Möglichkeiten für interessante Studien. Da die hauptsächlichen Publikationen zu diesem Themenkreis in das Ende der achtziger und in die neunziger Jahre datieren, kann behauptet werden, daß die Forschung noch am Beginn steht.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Rheumatologie 57 (1998), S. S23 
    ISSN: 0340-1855
    Keywords: Key words Fibromyalgia pain ; descending antinociception ; dorsal horn neurons ; spinal cord block ; Schlüsselwörter ; Fibromyalgie-Schmerzen ; deszendierende Antinozizeption ; Hinterhornneurone ; Kälteblock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Hypothese wird diskutiert, daß Fibromyalgie-Schmerzen durch eine Dysfunktion des deszendierenden, antinozizeptiven Systems (mit)verursacht sind. Ergebnisse aus Tierexperimenten zeigen, daß eine Unterbrechung des Systems durch Kühlung des Rückenmarks folgende Wirkungen auf nozizeptive Hinterhornneurone hat: 1. Anstieg der Ruheaktivität, 2. Senkung der mechanischen Reizschwelle, und 3. verstärkte Antworten auf Schmerzreize. Die Wirkung der deszendierenden Antinozizeption auf die Reizeffekte von tiefen Nozizeptoren war stärker als die Wirkung auf die Effekte von Nozizeptoren der Haut. Falls ähnliche Effekte auch bei Patienten auftreten, ist zu erwarten, daß eine Störung der deszendierenden Antinozizeption folgende Symptomebewirkt: 1.Spontanschmerzen (Ruheaktivität), 2. Druckschmerzhaftigkeit (Senkung der Schwelle) und 3. Hyperalgesie (verstärkte Antworten auf Schmerzreize). Die Änderungen sollten vorwiegend Schmerzen aus tiefen Geweben betreffen, da die deszendierende Antinozizeption hauptsächlich auf Reizeffekte von tiefen Nozizeptoren wirkt.
    Notes: Summary The hypothesis is discussed that a dysfunction of the descending antinociceptive system may underly the pain of fibromyalgia. Data from animal experimentation show that an interruption of the system by spinal cord cooling leads to (1) increase in ongoing activity, (2) lowering in stimulation threshold, and (3) increase in response magnitude in nociceptive dorsal horn neurons. The influence of the descending system was stronger on the responses to input from deep nociceptors than to input from cutaneous nociceptors. If similar changes occur also in patients, an impairment of the tonicly active descending system should be followed by (1) spontaneous pain (ongoing activity), (2) tenderness (lowering in mechanical threshold), and (3) hyperalgesia (increased responses to noxious stimuli). These changes should affect mainly deep pain, because the antinociceptive system influences predominantly input from deep nociceptors.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Rheumatologie 57 (1998), S. S8 
    ISSN: 0340-1855
    Keywords: Key words ; Antidromic vasodilatation ; axon reflex ; flare reaction ; plasma extravasation ; substance P ; calcitonin gene-related peptide ; galanin ; capsaicin ; fibromyalgia ; Schlüsselwörter ; Antidrome Vasodilatation ; Axonreflex ; Flarereaktion ; Plasmaextravasation ; Substanz P ; Calcitonin Gene-Related Peptide ; Galanin ; Capsaicin ; Fibromyalgie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung C-Faser Nozizeptoren haben neben ihrer afferenten auch lokale efferente Funktionen, wie Vasodilatation, Plasmaextravasation und die Modulation neuronaler Aktivität, die durch Freisetzung der Neuropeptide Substanz P, Neurokinin A und Calcitonin Gene-Related Peptide (CGRP) an der peripheren Endigung ausgelöst werden. In der Haut der Säugetiere (einschließlich Mensch) ist CGRP der wichtigste Mediator der Flarereaktion. Die Vasodilatation wird beim Schwein durch Aktivierung von spezifischen Hitzenozizeptoren induziert. Bei der Taube wird die antidrome Vasodilatation durch intrinsisch freigesetztes Galanin gehemmt. Plasmaextravasation kann beim Schwein in Hautblasen und mit der Mikrodialyse durch Histaminsuperfusion, nicht aber durch elektrische Stimulation und Capsaicin, ausgelöst werden. Die neurogene Komponente der Histaminantwort (64%) wird durch NK2-Rezeptoren vermittelt und kann durch CGRP moduliert werden. Die genannten Neuropeptide können zur Sensibilisierung und unter bestimmten Bedingungen zur Stimulation von Nozizeptoren führen. Die erhöhte Sensitivität der Flarereaktion bei Fibromyalgiepatienten deutet auf eine veränderte Funktion der C-Faser Nozizeptoren hin.
    Notes: Summary C-fiber nociceptors not only serve afferent but also local efferent functions. The local efferent functions, such as vasodilatation, axon reflex flare reaction, plasma extravasation, and modulation of neuronal activity, are mediated via a local release of substance P, neurokinin A, and calcitonin gene-related peptide (CGRP) from the peripheral ending. CGRP is the main mediator of the capsaicin-induced flare reaction in the mammalian skin (including humans). In the pig skin the vasodilatation is due to activation of specific heat nociceptors. In the pigeon, antidromic vasodilatation is markedly inhibited by intrinsic galanin. Plasma extravasation in the pig skin blister base or using microdialysis can be evoked by histamine, but not by electrical stimulation or capsaicin. The neurogenic component of the histamine response (64%) appears to be mediated via NK2 receptors and can be modulated by CGRP. There is some evidence that the neuropeptides can also sensitize or stimulate nociceptors. Since in the fibromyalgia syndrome an increased sensitivity of the flare reaction has been observed, the hyperalgesia might be partly due to altered functions of C-fiber nociceptors.
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  • 10
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    Zeitschrift für Rheumatologie 57 (1998), S. S19 
    ISSN: 0340-1855
    Keywords: Key words ; Fibromyalgia syndrome ; laser evoked potentials ; auditory evoked potentials ; hyperalgesia ; hypervigilance ; attention ; Schlüsselwörter ; Fibromyalgie Syndrom ; Laser evozierte Potentiale ; akustisch evozierte Potentiale ; Hyperalgesie ; Hypervigilanz ; Aufmerksamkeit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die bisherige Forschung zu dem Phänomen erhöhter Schmerzempfindlichkeit beim Fibromyalgie Syndrom (FS) ergab Hinweise sowohl für eine erhöhte Schmerzstärke nach nozizeptiven Reizen (Hyperalgesie) als auch für eine generelle Verstärkung sensorischer Wahrnehmungen (Hypervigilanz). Um zwischen diesen beiden Aspekten gestörter sensorischer Verarbeitung zu unterscheiden, wurden zerebral evozierte Potentiale nach kurzen, schmerzhaften Laser- und auditiven Reizen bei 10 FS-Patienten registriert. Die Ergebnisse wurden mit denen von gleichaltrigen schmerzfreien Kontrollpatienten verglichen. Die Amplituden der Komponenten mittlerer (N1) und später (P2) Latenz aus den Laser evozierten Potentialen (LEP) waren bei FS-Patienten signifikant größer als in den Kontrollen. Auch die Laser-Schmerzschwelle, nicht aber die Empfindungsschwelle, waren bei FS-Patienten gegenüber der Kontrollgruppe erniedrigt. Im Gegensatz hierzu unterschieden sich die akustisch evozierten Potentiale zwischen den beiden Studiengruppen nicht. Die vergrößerten N1- und P2-Amplituden der LEP deuten auf eine verstärkte sensorische und aufmerksamkeitsabhängige Verarbeitung nozizeptiver Information bei FS hin. Das Fehlen von Unterschieden nach auditiven Reizen stellt das Konzept der Hypervigilanz in Frage. Allerdings wird die Bedeutsamkeit unangenehmer Intensitäten auditiver Reize, die in dieser Studie nicht verwendet wurden, als Voraussetzung diskutiert, um übermäßige perzeptive Reaktionen auch durch nicht-nozizeptive Reize bei FS auslösen zu können.
    Notes: Summary Past research on the phenomenon of enhanced pain sensitivity in fibromyalgia syndome (FS) revealed evidence for both a higher pain magnitude in response to nociceptive stimuli (hyperalgesia) and a general perceptual amplification of sensations (hypervigilance). In order to distinguish between these two aspects of disturbed sensory processing in FS, cerebral evoked potentials after brief painful laser and auditory stimuli were measured in 10 FS patients. Results were compared with those from age-matched painfree controls. Amplitudes of middle-latency (N1) and long-latency (P2) laser evoked potentials (LEPs) were significantly higher in FS than in controls. Furthermore, laser intensity at pain but not at sensation threshold was lower in FS than in controls. However, auditory evoked potentials (AEPs) did not differ between groups. Enhanced N1 and P2 amplitudes of LEPs suggest stronger sensory and attentional processing of nociceptive information in FS, respectively. The concept of hypervigilance is challenged by the failure to find differences in auditory perception among FS and control patients. Yet, the importance of unpleasant intensities of auditory stimulation, not applied in this study, to reveal abnormal non-nociceptive perceptual amplification in FS is discussed.
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  • 11
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    Zeitschrift für Rheumatologie 57 (1998), S. S27 
    ISSN: 0340-1855
    Keywords: Key words ; Akinetic movement disorder ; Parkinson ; fibromyalgia ; basal ganglia ; cell death ; Schlüsselwörter ; Akinetische Bewegungsstörungen ; Parkinson ; Fibromyalgie ; Basalganglien ; Zelltod
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Patienten mit Fribromyalgie leiden manchmal unter sensiblen und Bewegungsstörungen, die eine gewisse Ähnlichkeit mit denjenigen bei akinetischen Syndromen aufweisen. Die Akinesie wird durch Funktionsstörungen in dem kortiko-thalamo-nigro-striatalen System und assoziierte Areale verursacht. Der Grund für diese Störung liegt bei der Parkinsonschen Krankheit in der verminderten Anzahl dopaminerger Neuronen in der Substantia nigra, pars compacta. Veränderungen anderer Neurotransmitter, wie GABA oder Serotonin, sowie in den Neurotransmitterreceptoren, sekundären Botenstoffen, und sekundären Modulierungen nach medikamentöser Behandlung treten auch auf. Die Ätiologie der nigralen Dysfunktion ist nur in seltenen Fällen bekannt. Toxische Substanzen und Mutationen gewisser Gene sind bekannte Beispiele in der Ätiologie von Bewegungsstörungen im Allgemeinen. In anderen akinetischen Syndromen, wie die Multisystemaffektion, die kortikobasale ganglionäre Degeneration und die progressive supranukleare Lähmung, wurde ein komplexerer Befall weitere Hirnareale festgestellt. Diese pathologisch-anatomischen Veränderungen haben typische klinische Folgerungen, die mittels Bildgebung und physiologischen Messungen in vivo untersucht werden können. Da die Basalganglien zudem eine Rolle in der Schmerzwahrnehmung spielen, erscheint eine vergleichende Untersuchung ihrer Störungen bei Nozizeption (inklusive Fibromyalgie) und bei Bewegungsstörungen vielversprechend, vor allem wenn es dann darum geht, neue, rationalere Therapiemodalitäten zu finden.
    Notes: Summary Patients with fibromyalgia sometimes have sign of a movement disorder in addition to sensory disturbances sometimes similar as those found in akinetic syndromes. Akinesia is due to disturbances in the functions of the cortico-thalamo-nigro-striatal system and associated areas. The reason of this dysfunction in Parkinson’s disease is a decreased nigral dopaminergic efferent innervation due to a neuronal degeneration in the pars compacta of the substantia nigra. Changes in other neurotransmitters, like GABA or serotonin, and in receptors and second messengers also occur, with additional modulation due to therapy. The aetiology of nigral malfunction is in only rarely known. Drugs and mutations of some genes are examples which give much insight in the pathogenesis of movement disorders in general. In other akinetic disorders, like multisystem atrophy, corticobasal ganglionic degeneration, and progressive supranuclear palsy, more complex patterns of degeneration have been found. This pathological anatomical disturbances have typical clinical effects which can be studied physiologically and with imaging in vivo. Since basal ganglia play also a role in pain, a comparative study of their involvement in movement disorders and nociception seems to be fruitful, especially in devising new therapeutic strategies.
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  • 12
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    Zeitschrift für Rheumatologie 57 (1998), S. S31 
    ISSN: 0340-1855
    Keywords: Key words ; Fibromyalgia syndrome ; nosology ; person-centered analyses ; biopsychosocial mechanisms ; course management ; Schlüsselwörter ; Fibromyalgie Syndrom ; Nosologie ; Personenzentrierte Dynamik ; Biopsychosoziale Mechanismen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Chronische großflächige Schmerzen im muskuloskelettalen System werden seit der Antike berichtet. Die kritische klinische und experimentelle Forschung zu diesem Thema wurde jedoch erst in den letzten ein bis zwei Jahrzehnten intensiviert. Bezüglich vielfältiger Aspekte dieses Problems existieren kontroverse Vorstellungen: Klassifikation und Nosologie, kausale Mechanismen, Verläufe und Folgen sowie therapeutische Strategien. Das Fibromyalgie Syndrom (FMS) ist keine Krankheit im herkömmlichen Sinne, sondern als eine funktionelle Störung anzusehen. Verschiedene typische Ausprägungen als auch disponierende Faktoren wurden bislang identifiziert. Unter diesen Gesichtspunkten ist für das Verständnis der komplexen multifaktoriellen Wechselwirkungen beim FMS eher ein neues biopsychosoziales Paradigma der personenbezogenen Dynamik erforderlich als die Suche nach einem spezifischen Agens oder Umweltfaktoren. Konzeptionelle Modelle zu Ätiologie und Forschungsmethoden sind bisland nur unzureichend entwickelt, um solche komplexen, multifaktoriellen Mechanismen zu untersuchen. Neue Wege der Forschung lassen verbesserte Behandlungsmethoden für FMS-Patienten erwarten.
    Notes: Summary Chronic widespread musculoskeletal pains have been recorded since antiquity. However, critical medical and experimental research on these conditions have been performed mainly within the past one or two decades. Controversy exists regarding many aspects of these common problems, including: classification and nosology; causation mechanisms; course and outcomes, as well as management strategies. Fibromyalgia syndrome (FMS) is not a disease. Neither a defined pathology nor specific etiological mechanisms have been documented. Instead, FMS may be considered a dysfunctional disorder. Constellations of typical, although diverse, manifestations have been identified as well as predisposing factors. Under such circumstances, a new biopsychosocial paradigm of person-centered dynamics, rather than an agent per se or the environment, is fundamental to understanding the complex multifactorial interactions in FMS. Conceptual models of etiology and research methodology to investigate such complex, multifactorial mechanisms are not yet well-developed. More effective research approaches and improved management of persons with FMS is expected to result from such new conceptual constructs.
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  • 13
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    Zeitschrift für Rheumatologie 57 (1998), S. S61 
    ISSN: 0340-1855
    Keywords: Key words ; Fibromyalgia syndrome ; genetic factors ; HLA system ; Schlüsselwörter ; Fibromyalgie Syndrom ; genetische Faktoren ; HLA-System
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Obwohl die familiäre Häufung des Fibromyalgie Syndroms (FMS) schon mehrfach beschrieben wurde, finden sich bislang nur wenige genetische Untersuchungen zu diesem Thema. So haben einige wenige Studien diese familiäre Häufung zusammen mit einer Assoziation im HLA System berichtet. Unsere eigene Forschungsgruppe hat aktuell in einer Studie die Verbindung von Fibromyalgie Syndrom und HLA System in Familien mit mehrfach an FMS Erkrankten untersucht.
    Notes: Summary Although familial occurrence of fibromyalgia syndrome (FMS) has been commonly observed, data on a genetic role in this condition are limited. A few studies have reported familial aggregation and association with HLA. We have studied genetic linkage of FMS with HLA in multicase families, and found a rather weak linkage of FMS with HLA (P〈0.029).
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  • 14
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    Journal of orofacial orthopedics 59 (1998), S. 127-138 
    ISSN: 1615-6714
    Keywords: Cephalometric analysis ; Class II malocclusion ; Magnets ; Straight-wire appliance ; Superelastic coils ; Schlüsselwörter ; Kephalometrie ; Klasse-II-Bißanomalie ; Magneten ; Straight-wire-Apparatur ; Superelastische Federn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurden 18 fortlaufend ausgewählte Patienten (bei Behandlungsbeginn durchschnittlich 14,7 Jahre alt) mit dentaler Klasse II, Tiefbiß und Platzmangel im oberen Zahnbogen untersucht. Während der ersten sechsmonatigen Behandlungsphase erfolgte die Distalisierung der ersten und zweiten oberen Molaren mittels sich abstoßender Samarium-Cobalt-Magneten auf der einen und superelastischer Nickel-Titan-Federn auf der kontralateralen Seite bei zur Bißöffnung eingesetzter frontaler Aufbißplatte. Die zweite Behandlungsphase von durchschnittlich 1,3 Jahren wurde mit einer Straightwire-Apparatur durchgeführt. Fernröntgenseitenbilder und Gipsmodelle wurden zu Behandlungsbeginn, nach der Molarendistalisierung, am Ende der aktiven Behandlung und ein Jahr nach Behandlungsabschluß angefertigt. Die Behandlung führte hauptsächlich zu dentalen Veränderungen. Die dentale Klasse II wurde durch körperliche Distalbewegung der oberen und Mesialbewegung der unteren Molaren in eine Klasse I korrigiert. Die Korrektur der Molarenrelation war auf der mit Federn behandelten Seite signifikant größer als auf der mit Magneten behandelten (durchschnittlich 3,4 mm gegenüber 3,0 mm). Trotz des Verankerungsverlustes während der Molarendistalisierung in Form einer Protrusion der oberen Schneidezähne um durchschnittlich 1,8 mm wurde der Netto-Overjet durch Klasse-II-Gummizüge durchschnittlich um 2,5 mm verringert. Die durchschnittliche Bißerhöhung um 2,6 mm war vorwiegend auf die Extrusion der Molaren zurückzuführen. Während der einjährigen Beobachtungszeit nach Abschluß der aktiven Behandlung wurden keine signifikanten dentalen oder skelettalen Veränderungen gefunden. Die Langzeitstabilität der Behandlungsergebnisse bedarf weiterer Untersuchungen.
    Notes: Abstract The investigation comprised 18 consectuvely selected patients, mean age 14.7 years at the start of treatment, with Class II malocclusion, deep overbite and space deficiency in the maxillary arch. The first phase of the treatment consisted of 6 months simultaneous distal movement of maxillary first and second molars with repelling samarium-cobalt magnets on one side and a superelastic nickel-titanium coil on the contralateral side together with an anterior biteplane to achieve bite opening. For the second phase of the treatment, a straight-wire appliance was used for an average treatment time of 1.3 years. Lateral head radiographs and dental casts were available at the start of treatment, after molar distalisation, at the end of treatment and 1 year post-treatment. The treatment resulted mainly in dental changes. The dental Class II molar relation was corrected to Class I by bodily distal movement of maxillary molars and by mesial movement of the mandibular molars. The correction of molar relation was significantly greater on coil sides than on magnet sides, mean 3.4 mm, and 3.0 mm, respectively. Despite anchorage loss associated with the maxillary molar movement, i. e. mesial movement of the maxillary incisors (mean 1.8 mm), the net overjet was reduced, mean 2.5 mm, by the use of Class II elastics. The average net improvement of bite opening was 2.6 mm, mainly due to extrusion of mandibular and maxillary molars. During the 1-year post-treatment period no significant dental or skeletal changes were found. The long-term implications of the treatment results need further consideration.
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  • 15
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    Applied Organometallic Chemistry 12 (1998), S. 409-417 
    ISSN: 0268-2605
    Keywords: antitumor activity ; cancer cell lines ; dibutyltins ; NCI ; organotins ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper reports the activity of four dibutyltin(IV)-N-arylidene-α-amino acid complexes against the National Cancer Institute (NCI) panel of 60 cell lines. The results indicated that three of the organotin complexes (C17H25NO3Sn, C18H27NO3Sn and C20H31NO3Sn) exhibit their highest cytotoxic effect on the NCI-522 (non-small cell lung cancer) cell line. The fourth complex, C21H27NO3Sn, exhibits its highest cytotoxic activity on the cell line RXF-631L (renal cancer). In general, a low to moderate cellular response was observed for all the organotin complexes, with at least one cell line in each subpanel of cells exhibiting a very low growth inhibition response to all the organotin complexes. The low-responding cell lines included HOP-62 (non-small lung cancer), DLD-1 (colon cancer), SF-539 (CNS cancer), SK-MEL-5 (melanoma), IGROV-1 (ovarian cancer) and RPMI-8226 (leukemia). The results also indicated that the compounds did not exhibit any significant subpanel activity and suggested that the compounds were not active in all the cell lines contained in any subpanel. The low to moderate activity of these compounds across the cell lines was attributed to the presence of nitrogen-bearing ligands which prevented the dissociation of the compound and the subsequent binding to DNA. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
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  • 16
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    Applied Organometallic Chemistry 12 (1998), S. 449-455 
    ISSN: 0268-2605
    Keywords: trimethylantimony ; biomethylation ; anaerobic bacteria ; inorganic antimony ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The volatile antimony compound trimethylantimony (TMA) was detected in headspace gases over anaerobic soil enrichment cultures spiked with potassium antimony tartrate. The presence of TMA was variable (12 positives from 104 cultures) and dependent upon both the inoculum source (environmental sample) and enrichment culture conditions. Positives for TMA formation were obtained with variable frequency for four of the six soils tested and for three types of enrichment culture, designed to encourage growth of nitrate-reducing, methane-producing or fermentative bacteria. The identity of the volatile antimony compound produced in each of the three types of enrichment culture was confirmed by gas chromatography-mass spectrometry and gas chromatography-atomic absorption spectroscopy. There was no evidence of any other volatile antimony compound in the headspace gases. These data suggest that the capability to generate TMA is widely distributed in the terrestrial environment and is attributable to different metabolic types of micro-organisms. © 1998 John Wiley & Sons, Ltd.
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  • 17
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    Applied Organometallic Chemistry 12 (1998), S. 467-467 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 18
    ISSN: 0268-2605
    Keywords: fungicidal activity ; Ceratocystis ulmi ; triphenyltin(IV) ; tributyltin(IV) ; phenolic bridge ; carboxylate bridge ; polymers ; trigonal bipyramidal structures ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methods of synthesis, elemental analysis, IR and NMR spectroscopic data and fungicidal activity against Ceratocystis ulmi are reported for a series of triorganotin esters of N-arylidene-ω-amino acids of general formula R3SnOCO(CH2)nN = CHAr (R = Ph, n-Bu; Ar = 2-HOC6H4, 2-HOC10H6; n = 1, 2, 3 and 5). The crystal structures for two of the compounds, tributyltin N-2-hydroxynaphthalidene glycinate (1) and tributyltin N-2-hydroxynaphthalidene-β-alaninate (2), have been determined. Although both of these compounds have a trans-R3SnO2 structure, in compound 1 the carboxylate group is monodentate and the fifth coordination position around the tin atom is taken up by a coordinated phenolic group, whereas in 2 the carboxylate group is bridging. These two examples thus correspond to the two different structures reported for trans-R3SnO2 complexes. Both compounds were found to be active against Ceratocystis ulmi, but there was no significant difference in their levels of biological activity against this particular fungus. Apart from compound 1, the other tributyltin compounds reported are believed to adopt the carboxylate bridging mode shown by compound (2).Crystal data: for 1, crystals monoclinic, space group P21/c, a = 12.9435(11) Å, b = 13.5769(10) Å, c = 15.7715(12) Å, β = 108.919(6)°, Z = 4, Rf = 0.046 and Rw = 0.058 for 1448 significant reflections; for 2, crystals monoclinic, space group C 2/c,a = 24.588(14) Å, b = 9.733(3) Å, c = 27.611(12) Å,β = 113.49(4)°, Z = 8, Rf = 0.053 and Rw = 0.069 for 3822 significant reflections. © 1998 John Wiley & Sons, Ltd.
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  • 19
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    Applied Organometallic Chemistry 12 (1998), S. 878-878 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 20
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    Applied Organometallic Chemistry 12 (1998), S. 801-807 
    ISSN: 0268-2605
    Keywords: metal-containing vinylic monomers ; vinylbenzoyl complexes ; cinnamoyl complexes ; tungsten-olefin monomers ; iron-olefin monomers ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of metal-containing vinylic monomers of the type LnM(COC6H4CH=CH2) and LnM (COCH=CHC6H5) [LnM = (η5-C5H5)Fe(CO)2, (η5-C5Me5)Fe(CO)2 and (η5-C5H5)W(CO)3] were prepared by the reaction of the appropriate metal anion with either 4-vinylbenzoyl chloride or cinnamoyl chloride. (η5-C5H5)(CO)2FeCOCH=CH2 was prepared by the reaction of Na[(η5-C5H5)Fe(CO)2] and acryloyl chloride, whereas the compound (η5-C5H5)(CO)2Fe(C6H4CH=CH2) was prepared via a transmetallation reaction using a palladium catalyst. All compounds were fully characterized using FTIR, 1H and 13C NMR spectroscopy and mass spectrometry. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 21
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    Applied Organometallic Chemistry 12 (1998), S. 879-879 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 22
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    Applied Organometallic Chemistry 12 (1998), S. 793-799 
    ISSN: 0268-2605
    Keywords: anticancer ; antineoplastic ; ferrocene/ferricenium ; biological redox ; free radical ; polyaspartamide ; tumor ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ferrocene/ferricenium redox system plays a significant role in biological oxidation, reduction and free-radical reactions. Of particular interest are the findings of earlier investigations which showed certain water-soluble ferricenium salts to possess appreciable antiproliferative activity against various murine tumor lines and a xenografted human colorectal adenocarcinoma. Solubility in water, a prerequisite for efficacious transport and dissipation in central circulation, was then proposed as a principal requirement for the ferrocene complex system to exert antineoplastic activity irrespective of the oxidation state in which it is administered. In order to shed more light on this question, we decided to investigate the antiproliferative properties of polymer-ferrocene conjugates containing the metal complex in the non-oxidized (ferrocene) form while fulfilling the critical requirement of water solubility. To this end, five selected, water-soluble conjugates, synthesized by reversible coupling of 4-ferrocenylbutanoic acid to variously structured polyaspartamides featuring pendant primary amino groups as coupling sites, were tested in vitro against cultured HeLa cells at concentrations up to 50 µg Fe ml-1. Optimal antiproliferative activities, with IC50 in the range of 2-7 µg Fe ml-1, were determined for three compounds possessing tertiary-amine functions susceptible to protonation at physiological pH. Lower activities (IC50 = 45-60 µg Fe ml-1) were demonstrated for two poly(ethylene oxide)-containing conjugates. However, no reasonable structure-performance relationships can be derived at this stage from the small number of compounds tested. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 23
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 24
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    Applied Organometallic Chemistry 12 (1998), S. 880-880 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 25
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    Applied Organometallic Chemistry 12 (1998), S. 855-859 
    ISSN: 0268-2605
    Keywords: butyltin ; phenyltin ; gibberellates ; antitumour ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization of di-n-butyl-, tri-n-butyl- and triphenyltin gibberellates are reported. Their antitumour activities in vitro against a panel of seven human tumour cell lines are given and compared with those of drugs used clinically. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 26
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    Applied Organometallic Chemistry 12 (1998), S. 873-876 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 27
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    Applied Organometallic Chemistry 12 (1998), S. 531-539 
    ISSN: 0268-2605
    Keywords: methylmercury ; estuarine sediment ; certification ; (BCR) ; quality control ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Legislation on methylmercury within the European Union (EU), e.g. in food (national regulations) or water (EC Directives), requires that the determinations are of proven quality; thus implies that they should be carried out under strict quality control (QC). One method of achieving good quality control in chemical analysis is to verify the analytical performance of methods by analysing Certified Reference Materials (CRMs). While CRMs of biological matrices (e.g. fish, mussels) are already available, there was a lack of materials for the QC of sediment analysis. This paper describes the preparation of an estuarine sediment reference material, the homogeneity and stability studies and the analytical work performed for the certification of the contents of total mercury and methylmercury. The results of a group of expert laboratories are discussed and the methods used to certify the mass fractions of total mercury (132 ± 3 mg kg-1 on a dry mass basis) and methylmercury (75.5 ± 3.7 μg kg-1 as CH3Hg+ on a dry mass basis) are described. © 1998 John Wiley & Sons, Ltd.
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  • 28
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    Applied Organometallic Chemistry 12 (1998), S. 571-576 
    ISSN: 0268-2605
    Keywords: zerovalent metals ; bromoalkyltriphenylphosphonium bromides ; methylmercuric acetate ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aqueous solutions of bromoalkyltriphenylphosphonium bromides react with zerovalent metals, causing their dissolution. The reaction initially follows second-order kinetics, with the rate depending on both metal and bromide concentrations. Zerovalent metals similarly react with aqueous methylmercuric acetate and other dissolved organometals. © 1998 John Wiley & Sons, Ltd.
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  • 29
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    Applied Organometallic Chemistry 12 (1998), S. 643-650 
    ISSN: 0268-2605
    Keywords: tributyltin ; sediment ; degradation ; coastal British Columbia ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Butyltin concentrations in the sediments of two coastal areas of British Columbia, Canada, are reported. Two recent box cores from the deepest basin in the Strait of Georgia were sectioned and analyzed by GC-atomic emission spectrometry. No butyltin compounds were detected above 0.5 μgSn kg-1 (dry weight) in either core. These results are compared to those for a previous (1991) core from the same area. In that study, tributyltin (TBT) concentrations were in the range 1-2 μgSn kg-1 down the core and were higher than those of either of the degradation products, dibutyltin (DBT) and monobutyltin (MBT). Radioisotope dating (210Po-210Pb counting methods) was used to establish the rates of sedimentation of 0.25 and 2.6 cm y-1 at the two sites. Data suggest that a combination of rapid deposition of new, less-contaminated material and degradation of previously deposited butyltin compounds has resulted in the observed absence. Thirty-three surface sediments from the northern BC coastal harbor at Prince Rupert, collected in 1995, were analyzed for butyltin residues by GC-FPD. Concentrations of TBT, DBT and MBT were in the ranges from below the appropriate limit of detection (LOD) to 1262, to 109 and to 37 μgSn kg-1, respectively. TBT/DBT ratios ranged from 0.2 to 62 with most above unity, indicating that there is continuing fresh input of TBT. The sources are almost exclusively large ocean-going vessels that use the harbor for long-term anchorage. These findings are discussed with reference to the global TBT status. © 1998 John Wiley & Sons, Ltd.
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  • 30
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    Applied Organometallic Chemistry 12 (1998), S. 577-584 
    ISSN: 0268-2605
    Keywords: organotin ; extraction ; analysis ; GC-FPD ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effects of: (1) the modifier type (methanol and formic, acetic and propionic acids), (2) complexing agents (diethylammonium diethyldithiocarbamate, ammonium pyrrolidinedithiocarbamate) either with or without acidic modifiers, (3) the extraction temperature (50-80 °C) and pressure (30-50 MPa), (4) the extraction procedure (static-dynamic or dynamic), and (5) the volume of static modifier, on the extraction efficiency of native butyl- and phenyl-tin compounds from sediment, were evaluated comprehensively. The highest extraction efficiency for butyl- and phenyl-tin compounds was obtained at 30 MPa and 50 °C by using CO2 modified with acetic acid (200 μl in the cell). Supercritical fluid extraction (SFE) extracts were hexylated and determined by GC-FPD using a 610 nm bandpass filter without any clean-up step. In summary, the developed analytical procedure is robust (no restrictor clogging; free from FPD interferences), it is low-cost (no complexing agents needed), it has a high sample throughput (〈3 h), it is independent of the matrix for the determination of butyltin compounds in sediment, and it provides the highest precision among the SFE procedures reported for organotin determination. © 1998 John Wiley & Sons, Ltd.
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  • 31
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    Applied Organometallic Chemistry 12 (1998), S. 585-590 
    ISSN: 0268-2605
    Keywords: butyltin ; estuarine microcosm ; environmental fate ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A radiotracer experiment was conducted in a controlled experimental ecosystem (microcosm) to determine the persistence and behavior of tributyltin (TBT) under conditions simulating a temperate, shallow estuarine ecosystem. Radiolabeled TBT was introduced to the estuarine microcosm, which contained estuarine water, sediment and fish. TBT and its degradation products were monitored for 40 days. TBT rapidly distributed among the compartments of the microcosm. The TBT half-life in the water column was 2.55 days for the first 11 days and then slowed to 13.4 days. More than 60% of the TBT and its metabolites were found in the sediment, indicating that the sediment was an important sink for butyltins. Higher concentrations of butyltins, relative to the water column concentrations, were found in the surface microlayer. TBT could be bioconcentrated by the fish to levels more than 200 times the exposure concentration, and underwent rapid degradation in the fish body, so that high concentrations of its metabolites were found in the fish. The concentrations of TBT adsorbed on the suspended particles were three orders of magnitude greater than that in dissolved form. © 1998 John Wiley & Sons, Ltd.
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  • 32
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    Applied Organometallic Chemistry 12 (1998), S. 591-599 
    ISSN: 0268-2605
    Keywords: arsenic speciation ; LC-ICP-MS ; validation ; urine samples ; background levels ; The Netherlands ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The method validation for the speciation of five arsenic species in urine samples by liquid chromatography hyphenated to inductively coupled plasma mass spectrometry is described. Arsenic species which are identified and quantified in urine samples are the anions of arsenic(III), arsenic(V), monomethylarsonic acid and dimethylarsinic acid, and the cationic arsenobetaine. Detection limits were obtained in the range 0.3-0.4 μg As l-1 while the repeatability was in the range 3-4% (RSD) for concentrations above five times the detection limit. Urine samples could be analysed directly after a ten-fold dilution step. Arsenic compound concentrations were determined in urine samples from a volunteer who consumed a portion of tuna fish high in arsenobetaine. It was found that arsenobetaine was excreted rapidly via the urine with maximum concentrations after 12 h. Nearly complete arsenobetaine excretion was reached after 48 h. Background levels of arsenic compounds were determined in 61 urine samples from non-exposed inhabitants of The Netherlands. © 1998 John Wiley & Sons, Ltd.
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  • 33
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    Applied Organometallic Chemistry 12 (1998), S. 763-770 
    ISSN: 0268-2605
    Keywords: siloxane network ; contact angle ; sol-gel reaction ; polydimethylsiloxane ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polydimethylsiloxane (PDMS) hybrid networks have been prepared by the reaction of PDMS(OH)2, average molecular weight 26 × 103, 43.6 × 103 and 58 × 103, and methyltriethoxysilane (MeTEOS, 10-60 wt%) using a dibutyltin dilaurate or dibutyltin diacetate catalyst. By hydrolysis and homo- and co-condensation, MeTEOS forms a siliceous domain (MeSD) and acts as a crosslinker for the PDMS domain. Kinetic studies showed that high MeTEOS and catalyst concentrations and reduction of free surface area favor fast gelation and efficiency in converting MeTEOS to the MeSD. Under the water-sparse conditions utilized, cure was slow and substantial evaporative loss of MeTEOS occurred. © 1998 John Wiley & Sons, Ltd.
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  • 34
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    Applied Organometallic Chemistry 12 (1998), S. 375-379 
    ISSN: 0268-2605
    Keywords: granular films ; pulsed laser deposition ; giant magnetoresistance ; microstructure ; magnetic properties ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An investigation into the microstructural properties of CoxAg1 - x films, grown by pulsed laser deposition, as a function of deposition and post-deposition annealing temperature is reported. Surface morphology and microstructure were investigated by XPS, SEM and TEM measurements. Magnetic measurements were used to gain further information on particle size distributions through the analysis of the temperature dependence of the irreversible magnetization. Depending on cobalt content, deposition and post-deposition annealing temperature, the maximum of the cobalt grains diameter distribution was estimated to be in the range 2-6 nm. © 1998 John Wiley & Sons, Ltd.
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  • 35
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    Applied Organometallic Chemistry 12 (1998), S. 381-386 
    ISSN: 0268-2605
    Keywords: nanoparticles ; magnetic susceptibility ; magnetic anisotropy ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dynamical behavior of γ-Fe2O3 particles dispersed in a polymer have been investigated by a.c. susceptibility and Mössbauer spectroscopy measurements. The effect of interparticle interactions on the relaxation time is satisfactorily described by a superparamagnetic model where the dipolar energy is determined by a statistical calculation for a disordered arrangement of particles with volume distribution and easy axes in random orientations. The results indicate that the single particle anisotropy energy is mainly determined by surface anisotropy and that the energy barrier increases with the interaction strength. © 1998 John Wiley & Sons, Ltd.
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  • 36
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    Applied Organometallic Chemistry 12 (1998), S. 881-881 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 37
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    Applied Organometallic Chemistry 12 (1998), S. 881-882 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 38
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    Applied Organometallic Chemistry 12 (1998), S. 883-884 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 39
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    Applied Organometallic Chemistry 12 (1998), S. 827-842 
    ISSN: 0268-2605
    Keywords: Scopulariopsis brevicaulis ; hydride generation ; antimony ; biomethylation ; biotransformation ; solid-phase extraction ; sudden infant death syndrome (SIDS) ; volatile antimony ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cultures of the fungus Scopulariopsis brevicaulis were grown in antimony-rich media. Although volatile compounds of other elements were readily detected in the culture headspace, volatile antimony compounds were formed irreproducibly and at only ultratrace levels. In order to monitor the media for nonvolatile methylantimony compounds, a method of sample preparation was developed, based on solid-phase extraction. This enabled the separation of large quantities of soluble inorganic antimony species from trace amounts of organoantimony compounds before speciation by HG-GC-AAS. By this methodology methylated antimony compounds were detected at concentrations of 0.8- 7.1 µg Sbl-1 in all media in which S. brevicaulis was grown in the presence of antimony(III) compounds. These methylantimony species were not detected in any of the nonliving or medium-only controls. Methylated compounds were not detected where S. brevicaulis was grown in the presence of antimony(V) compounds. This is the first study to show that antimony(III) compounds are biomethylated by S. brevicaulis under aerobic-only growth conditions. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 40
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 41
    ISSN: 0268-2605
    Keywords: carbohydrate-modified phenylsiloxane ; surfactants ; wetting behaviour ; superspreading ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dynamic wetting behaviour on a perfluorinated, low-energy solid has been investigated for a carbohydrate-modified phenylsiloxane surfactant. The surfactant concentration, the rate of interface generation and the [solid/liquid interface area] : [liquid/vapour interface area] ratio were varied systematically. Dynamic data for the liquid/vapour (γlv) and solid/liquid (γsl) interfacial tension as well as their Lifshitz-van der Waals and donor-acceptor contributions were determined under strictly controlled conditions. Since γsl reacts sensitively to variations of the surfactant concentration and the rate of interface generation, the covering of the liquid/non-polar solid interface is assumed to be a spreading limiting factor. The corresponding γlv values remain constant and close to those obtained under equilibrium conditions. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 42
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    Applied Organometallic Chemistry 12 (1998), S. 523-529 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 43
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    Applied Organometallic Chemistry 12 (1998), S. 559-563 
    ISSN: 0268-2605
    Keywords: tributyltin ; surface microlayer ; dynamic model ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The transport dynamics of tributyltin (TBT) between the surface microlayer and subsurface water were studied in experimental systems which simulated different surface sea states. A dynamic model was derived from a diffusion equation to describe the dynamics of the TBT transport process. With this dynamic model diffusion coefficients were determined, and the effects of surface sea states and temperature on the TBT transport process between the surface microlayer and subsurface water were also studied. Turbulence, breaking waves and elevated temperature can accelerate this transport. © 1998 John Wiley & Sons, Ltd.
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  • 44
    ISSN: 0268-2605
    Keywords: methylmercury ; analysis ; HPLC- ICP MS ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel technique has been developed for the determination of trace amounts of methylmercury in various sample matrices. The newly developed HPLC method makes it possible to separate methylmercury and inorganic mercury with ultrasonic nebulization and detection by ICP MS for different mercury isotopic masses. The isotope-specific detection allows the application of the species-specific isotope addition method for the determination of methylmercury with a correction for artifact formation. The well-known water-vapour distillation method was used in combination with an enriched stable inorganic mercury isotope (200Hg2+) for the separation of methylmercury from various matrices. The subsequent determination of CH3 - 200Hg+ generated from 200Hg2+ was used in the correction for artifact formation during sample preparation. In comparison with a previously developed HPLC coupling technique with HPF-HHPN (high-performance flow/­hydraulic high-pressure nebulization), the stability of the detection procedure was improved considerably. The limit of detection (S/N = 3) for methylmercury was calculated to be about 0.015 μg kg-1. © 1998 John Wiley & Sons, Ltd.
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  • 45
    ISSN: 0268-2605
    Keywords: methylmercury ; solid-phase microextraction ; gas chromatography-atomic fluorescence ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analytical method is described for methylmercury determination in fish and aqueous samples using solid-phase microextraction (SPME) followed by gas chromatography-atomic fluorescence spectrometry (GC-AFS). The procedure involves aqueous-phase derivatization of methylmercury species with sodium tetraethylborate in a sample vial and subsequent extraction with a silica fiber coated with poly-­(dimethylsiloxane). The mercury derivatives are desorbed in the splitless injection port of a gas chromatograph and subsequently analyzed by GC-AFS. The headspace SPME procedure is used and parameters affecting the extraction, adsorption and desorption are evaluated. Results for methylmercury analysis in standard reference material (DORM-2) and fish samples are presented. © 1998 John Wiley & Sons, Ltd.
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  • 46
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    Applied Organometallic Chemistry 12 (1998), S. 635-641 
    ISSN: 0268-2605
    Keywords: arsenobetaine ; arsenocholine ; non-hygroscopic ; NMR ; FAB MS ; ICP MS ; synthesis ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multigram quantities of arsenobetaine bromide and arsenocholine iodide were synthesized from trimethylarsine using uncomplicated techniques. Arsenobetaine bromide and arsenocholine iodide are both non-hygroscopic. Arsenocholine iodide is, however, light-sensitive and should be used with actinic glassware. Both compounds were characterized by elemental and spectroscopic techniques and found to be suitable for use as primary analytical standards. © 1998 John Wiley & Sons, Ltd.
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  • 47
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    Applied Organometallic Chemistry 12 (1998), S. 659-666 
    ISSN: 0268-2605
    Keywords: polymers ; polyphosphazenes ; synthesis ; surfaces ; surface reactions ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The macromolecular substitution approach for the synthesis of polyphosphazenes provides access to many different polymers. However, it precludes the use of reagents that contain two or more functional groups because such compounds would cause extensive crosslinking of the chains. This presents a problem because many of the uses for which polyphosphazenes seem ideally suited require the presence of -OH, -COOH, -NH2, -SO3H, -PR2 and other functional units in the side-chain structure. We have developed two approaches to introduce such active sites: (1) protection-deprotection reactions; and (2) direct reactions of active reagents with the organic side-groups of non-functional poly(organophosphazenes). These methods have been applied both at the molecular level and in the form of reactions carried out only at polymer surfaces. The resultant polymers have special properties that are valuable in the micro-encapsulation of sensitive biological agents; in the formation of hydrophobic, hydrophilic, or adhesive surfaces; in crosslinking reactions; and in the development of solid polymer electrolytes, bio-erodible polymers, pH-triggered hydrogels, polymer blends and interpenetrating polymer networks. Overall, more than 700 different polyphosphazenes are now known, and a large number of these are functional macromolecules targeted for specific property combinations and uses. © 1998 John Wiley & Sons, Ltd.
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  • 48
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    Applied Organometallic Chemistry 12 (1998), S. 707-713 
    ISSN: 0268-2605
    Keywords: polyhedral oligomeric silsesquioxane ; hybrid ; thermoplastic ; polymer ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A diverse and entirely new class of monomer and polymer technology based on polyhedral oligomeric silsesquioxane (POSS) reagents has been developed. POSS reagents are unique in that they are physically large (approx. 15 Å diameter and 1000 amu) and are composed of a robust silicon-oxygen framework that can be easily functionalized with a variety of organic substituents. Appropriate functionalization of POSS cages allows for their incorporation into traditional thermoplastic resins without modification of existing manufacturing processes. The incorporation of POSS segments into linear copolymer systems results in increased glass transition and decomposition temperatures, increased oxygen permeability and reduced flammability and heat evolution, as well as modified mechanical properties relative to conventional organic systems. © 1998 John Wiley & Sons, Ltd.
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  • 49
    ISSN: 0268-2605
    Keywords: organophosphazenes ; liquid crystals ; phase transition ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organophosphazenes with a similar mesogenic moiety were prepared and their mesogenicity was studied by differential scanning calorinetry (DSC) measurements and polarizing microsope observations. In cyclotriphosphazenes with alk-­oxybiphenyl and Schiff base moieties, mesomorphic phase transitions were observed, but no mesomorphic phase was observed for the corresponding cyclotetraphosphazenes. In polyphos-­phazenes with an alkoxybiphenyl moiety, no mesomorphic phase was observed. The molecular structure of cyclotriphosphazenes facilitated the formation of a mesomorphic layer structure; in contrast, the formation of a mesomorphic layer structure did not occur in cyclotetraphosphazenes and polyphosphazenes, even though they bore a similar mesogenic moiety. Moreover, in cyclotriphosphazenes with an optically active alkoxybiphenyl group, a smectic C* phase was observed. The spontaneous polarization of the compound was -190 μ C m-2 at 436 K in 25 μ in cell using the triangular-wave method. © 1998 John Wiley & Sons, Ltd.
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  • 50
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    Applied Organometallic Chemistry 12 (1998), S. 657-657 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 51
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    Applied Organometallic Chemistry 12 (1998), S. 781-785 
    ISSN: 0268-2605
    Keywords: phosphonium ; polymer ; monomer ; film ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(arylene ether) main-chain phosphonium ionomers were successfully synthesized and characterized. The reaction scheme involved first preparing the poly(arylene ether phosphine oxide) by a nucleophilic step or condensation polymerization of bisphenolates on activated aryl halides, wherein phenyl phosphine oxide was the activating group. High-molecular-weight, tough, film-forming polymers were produced with glass transition temperatures of 200°C or higher. The resulting materials were successfully reduced using phenylsilane in refluxing chlorobenzene. The derived phosphine or phosphine/phosphine oxide copolymer was reacted with alkyl halides to produce the phosphonium salts. The resulting materials showed enhanced hydrophilicity and in some cases could be successfully dispersed in water. In addition, chromophores such as Methyl Orange and Methyl Red were combined with the backbone ionomer to produce new film-forming, ionically linked species. The materials are of general interest for situations where water-dispersible intermediates, e.g. coatings, fiber sizings etc. are required. The phosphonium salts can be converted back to the phosphine oxide in fairly high yields by simple thermal methods and in quantitative yield by chemical methods (e.g. the Wittig reaction). © 1998 John Wiley & Sons, Ltd.
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  • 52
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    Applied Organometallic Chemistry 12 (1998), S. 681-693 
    ISSN: 0268-2605
    Keywords: ceramics ; preceramic polymers ; SiNCB composites ; boron nitride ; boron ; silicon ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Our recent work directed at the design, synthesis, characterization and applications of new types of polyborazylene and polyborosilazane polymers is reviewed with a focus on the use of these polymers as processable precursors to BN and SiNCB composites. A design strategy based on the controlled functionalization of preformed polymers with pendant groups of suitable compositions and crosslinking properties has been employed to yield second-generation dipentylamine-polyborazylene (DPA) and pinacolborane-hydridopolysilazane (PIN-HPZ) polymers, which, unlike the parent polyborazylene (PB) and the borazine-hydridopolysilazane (B-HPZ) polymers, are stable as melts and can be easily melt-spun into polymer fibers. Subsequent pyrolyses of these polymer fibers then provide excellent routes to BN and SiNCB ceramic fibers. © 1998 John Wiley & Sons, Ltd.
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  • 53
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    Applied Organometallic Chemistry 12 (1998), S. 285-291 
    ISSN: 0268-2605
    Keywords: mushroom ; arsenic speciation ; HPLC-ICP-MS ; dimethylarsinic acid ; arsenobetaine ; trimethylarsine oxide ; toxicological evaluation ; soil contamination ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Samples of the edible mushroom Laccaria amethystina, which is known to accumulate arsenic, were collected from two uncontaminated beech forests and an arsenic-contaminated one in Denmark. The total arsenic concentration was 23 and 77 μg  As g-1 (dry weight) in the two uncontaminated samples and 1420 μg As g-1 in the contaminated sample. The arsenic species were liberated from the samples using focused microwave-assisted extraction, and were separated and detected by anion- and cation-exchange high-performance liquid chromatography with an inductively coupled plasma mass spectrometer as arsenic-selective detector. Dimethylarsinic acid accounted for 68-74%, methylarsonic acid for 0.3-2.9%, trimethylarsine oxide for 0.6-2.0% and arsenic acid for 0.1-6.1% of the total arsenic. The unextractable fraction of arsenic ranged between 15 and 32%. The results also showed that when growing in the highly arsenate-contaminated soil (500-800 μg As g-1) the mushrooms or their associated bacteria were able to biosynthesize dimethylarsinic acid from arsinic acid in the soil. Furthermore, arsenobetaine and trimethylarsine oxide were detected for the first time in Laccaria amethystina. Additionally, unidentified arsenic species were detected in the mushroom. The finding of arsenobetaine and trimethylarsine oxide in low amounts in the mushrooms showed that synthesis of this arsenical in nature is not restricted to marine biota. In order to minimize the toxicological risk of arsenic to humans it is recommended not to consume Laccaria amethystina mushrooms collected from the highly contaminated soil, because of a genotoxic effect of dimethylarsinic acid observed at high doses in animal experiments. © 1998 John Wiley & Sons, Ltd.No Abstract.
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  • 54
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    Applied Organometallic Chemistry 12 (1998), S. 299-299 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 55
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    Applied Organometallic Chemistry 12 (1998), S. 299-301 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 56
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    Applied Organometallic Chemistry 12 (1998), S. 301-301 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 57
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 58
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    Applied Organometallic Chemistry 12 (1998), S. 327-335 
    ISSN: 0268-2605
    Keywords: zinc sulphide ; precipitation ; nanocrystallites ; nanopores ; optical transmission spectroscopy ; vibrational spectroscopy ; Raman spectroscopy ; X-ray diffraction ; transmission electron microscopy ; thermogravimetric analysis ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: During the synthesis of ZnS powders by wet chemical precipitation, the formation of nanoporous spheres is observed. The powders have been investigated using thermogravimetric analysis, X-ray diffraction and optical spectroscopies. Nanopore formation can be explained by several stages of growth. The formation of nanoparticles as primary particles is followed by their agglomeration forming secondary particles. These secondary particles are monodispersed spheres with a considerable porosity, because the agglomeration of the nanoparticles is unlikely to be volume-filling. The voids or nanopores formed by this agglomeration process in the secondary particles is estimated to comprise around 35% of the sphere volume. They are mainly filled with water and the residues of the chemical reagents. Water in the pores partially reacts with ZnS and forms hydrated sulphates. The chemical reagents used for the precipitation reactions are also found to be bound to the nanocrystallite's surfaces as ligands in some cases. Depending on the reaction conditions and reagents, the agglomeration of the nanoparticles can also be modified or hindered by the use of complexing agents acting as a sterically stabilizing surface layer on the nanocrystallites. The agglomeration of nanoparticles to larger units being a general phenomenon, this use of complexing agents to control pore formation and agglomerate size should be applicable to other nanocrystalline systems. © 1998 John Wiley & Sons, Ltd.
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  • 59
    ISSN: 0268-2605
    Keywords: α-Fe2O3 ; nanoparticles ; Morin transition ; antiferromagnetism ; weak ferromagnetism ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The magnetic properties of α-Fe2O3 nanoparticles of different shapes (spherical, rhombohedral and acicular), prepared as powders by a chemical route, have been investigated. The particle size effect on the Morin transition (TM = 263 K in the bulk system) have been studied by analyzing the temperature dependence of the zero-field-cooled (ZFC) and field-cooled (FC) magnetization. For spherical (average diameter between 10 and 50 nm) and rhombohedral (edge between 30 and 350 nm) particles, the Morin temperature was found to decrease with decreasing particle size and increasing magnetic field. On the other hand, acicular particles (major axis between 300 and 700 nm, minor axis between 70 and 100 nm) do not show the Morin transition, unless annealed. © 1998 John Wiley & Sons, Ltd.
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  • 60
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    Applied Organometallic Chemistry 12 (1998), S. 361-365 
    ISSN: 0268-2605
    Keywords: silicon nanoparticles ; optical properties ; CO2 laser ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silicon nanoparticles have been synthesized by heating reactant gases with a 500 W CO2 laser. A technique based on scattering of He-Ne laser light by particulates in a reaction flame has been developed for probing the particle size evolution during the process, in order to scale down the particle diameter (under 10 nm). The optical and structural properties of laser-synthesized silicon nanopowders obtained in different runs are reported. © 1998 John Wiley & Sons, Ltd.
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  • 61
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    Applied Organometallic Chemistry 12 (1998), S. 353-360 
    ISSN: 0268-2605
    Keywords: surface chemistry ; sodium nanoclusters ; optical spectroscopy ; plasmon excitation ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of molecular adsorbate layers on surface plasmon excitation in small supported metal particles has been investigated and exploited to study adsorption reactions on their surfaces. For this purpose sodium nanoclusters on quartz and LiF substrates served as model systems. Their optical transmission spectra are dominated by two maxima which are due to the excitation of surface plasmon resonances in the direction of the long and short axes of the oblate particles. By recording the spectra under ultrahigh-vacuum conditions and, subsequently, after exposure to gases such as O2, N2O, CO2, H2 and N2, changes in the optical spectra can be identified if the clusters are covered by as little as half a molecular monolayer. Depending on the adsorbed molecules, different modifications of the maximum position, the width and the amplitude of the surface plasmon resonances are observed. The results of a series of measurements together with calculations using the quasi-static approximation indicate that the variations in the spectra allow one to distinguish between physisorption and chemisorption, i.e. to characterize the strength of the chemical bond. In addition, diffusion of the molecules into the bulk of the particles can be detected. Particularly interesting is the observation that the clusters can experience a change in their shape if gases such as O2 or CO2 react with their surface. © 1998 John Wiley & Sons, Ltd.
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  • 62
    ISSN: 0268-2605
    Keywords: alumina ; nanoporous membranes ; nanocomposites ; templates ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three different examples have shown that nanoporous alumina membranes serve as ideal templates for the formation of nanostructured materials and also as a support of those materials in composites. The unique properties of such membranes (transparency, chemical resistivity, thermal stability, adjustable pore sizes etc.) and the very simple mode of generating these composites are the benefits of using this inorganic template material.
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  • 63
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    Applied Organometallic Chemistry 12 (1998), S. 303-303 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 64
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    Applied Organometallic Chemistry 12 (1998), S. 427-433 
    ISSN: 0268-2605
    Keywords: laser ; chemical vapour deposition ; thin films ; Si/C/H materials ; divinylsilane ; silicon carbide ; polycarbosilane ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transversely excited atmospheric (TEA) CO2 laser-induced decomposition of divinylsilane in the gas phase yields unsaturated C2-C4 hydrocarbons, benzene and vinylsilane, and it represents a convenient process for chemical vapour deposition of thin solid films composed of silicon carbide and polycarbosilane. © 1998 John Wiley & Sons, Ltd.
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  • 65
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    Applied Organometallic Chemistry 12 (1998), S. 435-438 
    ISSN: 0268-2605
    Keywords: tributyltin ; radiolabelling ; 113Sn ; synthesis ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method of synthesis of tributyl[113Sn]tin,­(n/C4H9)3113Sn(IV), from commercially avail-­able inorganic 113Sn(IV) is presented. Inorganic tin is first extracted in diethyl ether and reacted with C4H9MgCl to produce tetrabutyltin, (C4H9)4113Sn, which is then debutylated with HgCl2. The resulting tributyl[113Sn]tin chloride is isolated from the reaction mixture by successive extractions with hexane and aqueous Na2S2O3. The yield is 40-60% and the product obtained is 〉98% pure. It has the same specific activity as the starting 113Sn(IV), i.e. up to 550 MBq mg-1 Sn, making it suitable for use in environmental fate and toxicology studies at concentrations relevant of those found in the aquatic environment. © 1998 John Wiley & Sons, Ltd.
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  • 66
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    Applied Organometallic Chemistry 12 (1998), S. 439-447 
    ISSN: 0268-2605
    Keywords: high-performance liquid chromatography ; hydride generation ; atomic fluorescence spectrometry ; photo-oxidation ; arsenic speciation ; human urine ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential of coupling anion-exchange high-performance liquid chromatography, hydride generation and atomic fluorescence spectrometry (HPLC-HG-AFS) for arsenic speciation is considered. The effects of hydrochloric acid and sodium tetrahydroborate concentrations on signal-to-background ratio, as well as argon and hydrogen flow rates, were investigated. Detection limits for arsenite, dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate were 0.17, 0.45, 0.30 and 0.38 μg l-1, respectively, using a 20-μl loop. Linearity ranges were 0.1-500 ng for As(III) and MMA (as arsenic), and 0.1-800 ng for DMA and As(V) (as arsenic). Arsenobetaine (AsB) was also determined by introducing an on-line photo-oxidation step after the chromatographic separation. In this case the limits of detection and linear ranges for the different species studied were similar to the values obtained previously for As(V). The technique was tested with a human urine reference material and a volunteer's sample. © 1998 John Wiley & Sons, Ltd.
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  • 67
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    Applied Organometallic Chemistry 12 (1998), S. 475-478 
    ISSN: 0268-2605
    Keywords: organomercurials ; symmetrization ; column chromatography ; organomercury halides ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The symmetrization reaction of organomercury(II) chlorides (RHgCl) to R2Hg and HgCl2 in toluene solution under identical conditions using a basic alumina column has been studied­in order to compare the effect of the nature of the R groups on the extent of symmetrization. The efficiency of symmetrization depends markedly on the electron-withdrawing nature of­R, varying from 90-94% for R = trichlorovinyl or phenyl to 11% for R = 2,6-dimethylphenyl.© 1998 John Wiley & Sons, Ltd.
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  • 68
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    Applied Organometallic Chemistry 12 (1998), S. 515-517 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 69
    ISSN: 0268-2605
    Keywords: iron ; clusters ; magnetic properties ; laser vaporization ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Clusters of iron produced in a laser vaporization source have been characterized with time-of-flight spectra and deposited on different substrates for production of films of varying thickness. The magnetic properties of these films with thicknesses of 60 and 120 nm were investigated using an alternating gradient magnetometer. The films exhibit mono-domain behavior from a broad size distribution which has been confirmed by transmission electron microscopy. Films were also investigated by Mössbauer spectroscopy, which showed fast relaxation in the particles at room temperature. © 1998 John Wiley & Sons, Ltd.
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  • 70
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    Applied Organometallic Chemistry 12 (1998), S. 485-489 
    ISSN: 0268-2605
    Keywords: polysulfone ; chelate-modified polysulfone ; DSC ; thermal stability ; X-ray ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chloro-terminated polysulfones with various molecular weights were chemically modified with bis(2,4-dihydroxybenzaldehyde)copper(II). The properties of modified polysulfones are compared with the unmodified ones, and an increase in glass transition temperatures, softening points and reduced viscosities of the former materials was observed. In addition, the chelate-modified polymers exhibited excellent thermal stability properties and semicrystalline patterns. Also, they provided transparent and flexible films. © 1998 John Wiley & Sons, Ltd.
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  • 71
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    Applied Organometallic Chemistry 12 (1998), S. 469-474 
    ISSN: 0268-2605
    Keywords: asymmetric catalysis ; diethylzinc ; alkylation ; chiral heterocyclic alcohols ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The asymmetric alkylation with diethylzinc of five heterocyclic aldehydes and benzaldehyde (for comparison) has been studied in the presence of two optically active amino alcohols: (S)-2-amino-1-butanol (AB) and (1S,2R)-N,N-dibutylnorephedrine (DBNE). A number of chiral (hetero)aromatic secondary alcohols were synthesized in high yields (95-98%) with enantioselectivity up to 92% enantiomeric excess (ee) in the presence of DBNE catalyst. Optically active thienyl and 4-pyridyl derivatives were prepared for the first time by catalytic asymmetric alkylation. The influence of the amount of DBNE on the enantioselectivity was investigated. In contrast to benzaldehyde, 2-furan- and 2-thiophene-carbaldehydes, in the case of 3- and 4-pyridinecarbaldehydes the ee values depend directly on the catalyst concentration. © 1998 John Wiley & Sons, Ltd.
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  • 72
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    Applied Organometallic Chemistry 12 (1998), S. 521-521 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 73
    ISSN: 0268-2605
    Keywords: HPLC-ICP-MS ; cetaceans ; pinnipeds ; arsenic ; arsenobetaine ; arsenocholine ; whales ; seals ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Total arsenic concentrations and the concentrations of individual arsenic compounds were determined in liver samples of pinnipeds [nine ringed seals (Phoca hispida), one bearded seal (Erginathus barbatus)] and cetaceans [two pilot whales (Globicephalus melas), one beluga whale (Deliphinapterus leucus)]. Total arsenic concentrations ranged from 0.167 to 2.40 mg As kg-1 wet mass. The arsenic compounds extracted from the liver samples with a methanol/water mixture (9:1, v/v) were identified and quantified by anion- and cation-exchange chromatography. An ICP-MS equipped with a hydraulic high-pressure nebulizer served as the arsenic-specific detector. Arsenobetaine (0.052-1.67 mg As kg-1 wet mass) was the predominant arsenic compound in all the liver samples. Arsenocholine was present in all livers (0.005-0.044 mg As kg-1 wet mass). The tetramethylarsonium cation was detected in all pinnipeds (〈0.009 to 0.043 mg As kg-1) but not in any of the cetaceans. The concentration of dimethylarsinic acid ranged from 〈 0.001 to 0.109 mg As kg-1 wet mass. Most of the concentrations for methylarsonic acid (〈0.001 to 0.025 mg As kg-1 wet mass) were below the detection limit. Arsenous acid and arsenic acid concentrations were below the detection limit of the method (0.001 mg As kg-1). An unknown arsenic compound was present in all liver samples at concentrations from 0.002-0.027 mg As kg-1. © 1998 John Wiley & Sons, Ltd.
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  • 74
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    Applied Organometallic Chemistry 12 (1998), S. 520-520 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 75
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    Applied Organometallic Chemistry 12 (1998), S. 520-520 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 76
    ISSN: 0268-2605
    Keywords: organotin ; N-(2-pyridylmethylene)arylamines ; IR ; NMR ; Mössbauer ; mutagenicity ; sister chromatid exchange ; cell cycle delay ; bone-marrow cells ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diorganotin(IV) dichloride complexes of the type R2SnCl2·L (R = methyl, ethyl, vinyl, t-butyl, n-butyl or phenyl; L = N-(2-pyridylmethylene)arylamine) have been synthesized and characterized on the basis of IR, NMR and 119Sn Mössbauer studies. Investigation of the complexes indicated that N-(2-pyridylmethylene)arylamines form distorted trans-octahedral complexes with R2SnCl2 similar to the well-known R2SnCl2·L. Cytogenetic toxicology testing has been performed for Et2SnCl2·L4 [L4 = N-(2-pyridylmethylene)-4-toluidine] in mouse bone-marrow cells in vivo since such testing is a regulatory requirement before new drugs are released. This tin compound induced delay in cell-cycle kinetics and sister chromatid exchanges (SCEs) significantly. The effect of Et2SnCl2·L4 was greater when endogenous glutathione (GSH) was depleted by buthionine sulphoximine (BSO). It seems that Et2SnCl2·L4 induces SCEs due to formation of adduct by binding on DNA which could interfere in DNA synthesis and cause delay in cell proliferation. Depletion of GSH could reduce the shielding effect of GSH on chromatin and allows more Et2SnCl2·L4 to bind on DNA. © 1998 John Wiley & Sons, Ltd.
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  • 77
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 78
    ISSN: 0268-2605
    Keywords: platinum compound antileukaemic ; cytotoxic ; DNA ; thiosemicarbazone ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: p-Isopropylbenzaldehyde thiosemicarbazone (p-is.TSCN) (1) reacts with [Pt(µ-Cl)(η3-C4H7)]2 to form a dinuclear [Pt(µ-Cl)(p-is.TSCN)]2 complex (2) and a cyclometallated cluster [Pt(p-is.TSCN)]4 (3). Biological testing of these complexes against HL-60 and U-937 human leukemic cells suggest that complexes 2 and 3 may be endowed with important cytotoxic activity properties since they exhibit IC50 values (50% inhibition of cell growth) in the micromolar range, as does the clinically used drug cisplatin (cis-DDP). Analysis of the interaction of compounds 2 and 3 with DNA indicates that the kinetics of DNA platination due to compounds 2 and 3 is faster than that of cisplatin and that after 24 h of incubation most of the platinum centers are bound to DNA. Thus, it is likely that the cytotoxic activity displayed by compounds 2 and 3 may be correlated with their high level of DNA platination. Copyright © 1998 John Wiley & Sons, Ltd.
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    Applied Organometallic Chemistry 12 (1998), S. 880-881 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 80
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    Applied Organometallic Chemistry 12 (1998), S. 819-825 
    ISSN: 0268-2605
    Keywords: monobutyltins ; dibutyltins ; tributyltins ; water ; sediment ; Osaka Bay ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concentration of tributyltin (TBT) in surface water from Osaka Bay ranged from 0.023 to 0.061 µg l-1 in 1989 and from not detected (ND) to 0.059 µg l-1 in 1990 while the proportion of TBT as a percentage of the total butyltins (BTs) was more than 40%. The concentration of TBT was also surveyed in the Port of Osaka and the Yodo River basin. TBT levels were highest in the estuary (the Port of Osaka), followed by sea areas (Osaka Bay) and rivers (Yodo River basin). A fairly high correlation coefficient between TBT concentration and salinity in water from the estuary and the sea areas was observed. This result shows that the TBT in the estuary water is diluted by seawater. Generally, the TBT concentrations in the water columns were distributed uniformly and the composition of the BTs was also constant. TBT was detected in sediment from Osaka Bay in the range from ND to 0.023 mg kg-1 dry weight with a high ratio of monobutyltin (MBT) to the total BTs. TBT in sediment core was also measured; its concentration decreased with core depth. It was estimated from these measurements that the release of TBT into Osaka Bay began in the 1960s. Copyright © 1998 John Wiley & Sons, Ltd.
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    Applied Organometallic Chemistry 12 (1998), S. 882-883 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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    Applied Organometallic Chemistry 12 (1998), S. 884-884 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
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  • 83
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    Applied Organometallic Chemistry 12 (1998), S. 861-871 
    ISSN: 0268-2605
    Keywords: diorganotin ; Pyrimidine ; complex ; Mössbauer ; IR ; NMR ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes formed between the diorganotin(IV) moieties, R2Sn(IV), and the ligand 2-mercaptopyrimidine, (H)SPym, were investigated. Complexes R2SnHal(SPym) and R2Sn(SPym)2 [R = Me, iPr, nBu, iBu, tBu, cyclohexyl(Cy), Ph] were synthesized, and characterized by elemental analysis. In the solid state, chelation of SPym through S and N donors was established by IR spectroscopy, and the nature of the environment of tin centers was investigated by 119Sn Mössbauer spectroscopy. From the dynamics of 119Sn nuclei determined by variable-temperature measurements on representative compounds [Me2SnCl(SPym) and Cy2SnBr(SPym)], as well as by point-charge model treatment of nuclear quadrupole splitting parameters, it was inferred that Me2SnCl-­(SPym) may assume a trans-Me2 octahedral coordination geometry around tin in a monodimensional polymer, or a monomeric trigonal-bipyramidal structure (distorted). The latter type of structure was assigned to the other R2SnHal(SPym) species, while R2Sn(SPym)2 complexes assume a trans-octahedral, or skew trapezoidal, tin environment. In CHCl3-CDCl3 solutions, monomeric species occur (according to vapor-pressure osmometry), where 1H and 13C NMR spectroscopic parameters of SPym indicate the persistence of Sn chelation by S and N donor atoms. The Me2SnCl(SPym) species assume trigonal-bipyramidal structures with a chelating SPym ligand, in CDCl3 and C2H5OH solutions, according to the coupling constants 1J(119Sn,13C), as well as IR and 119Sn Mössbauer spectroscopic data. 119Sn NMR parameters fully correspond with data for the homologous complexes with 2-mercaptopyridine. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 84
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    Applied Organometallic Chemistry 12 (1998), S. 601-611 
    ISSN: 0268-2605
    Keywords: tributyltin ; triphenyltin ; bioavailability ; bioconcentration factors ; humic substances ; pH dependence ; speciation ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bioconcentration of triphenyltin (TPT) and tributyltin (TBT) was studied in the freshwater organisms Daphnia magna (zooplankton), Chironomus riparius (sediment organism) and Thymallus thymallus (fish yolk-sac larvae). TPT bioconcentration factors (BCFs) at pH 8 were highest for Thymallus (2200), followed by Chironomus (680) and Daphnia (190). The differences could not be fully explained by different total lipid contents. Metabolism and lower bioconcentration were observed for TBT in Chironomus. The BCFs of both TBT and TPT were higher at pH 8 than at pH 5, but the difference was much less pronounced than predicted by the octanol-water partition model. This suggests that, besides the hydroxide species (TBTOH and TPTOH), the cations (TBT+ and TPT+) are also taken up by the organisms to some extent and that the octanol-water partition model underestimates the uptake of the charged species. Low concentrations of humic substances (HS) led to small reduction in the bioconcentration of TPT in Daphnia and Thymallus, and a significant reduction occurred at relatively high concentrations of HS (〉10 mg C l-1). The results of this study provide an important basis for future investigations aiming at a better understanding of the bioavailability and fate of TBT and TPT in freshwater ecosystems. © 1998 John Wiley & Sons, Ltd.
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  • 85
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    Applied Organometallic Chemistry 12 (1998), S. 651-656 
    ISSN: 0268-2605
    Keywords: butyltin ; TBT ; DBT ; MBT ; beluga whales ; St Lawrence River estuary ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fifty-two beluga whale samples (Six liver samples, and 46 blubber samples including ones from different depths of the fat layer) from the St Lawrence River, Canada, were analyzed for butyltin compounds (mono-, di-, and tri-butyltin) with a view to investigating the occurrence and contamination of butyltin in these animals. A special procedure was also developed for the determination of butyltin compounds in blubber samples with high lipid content (up to 95%). Total-butyltin concentrations in liver samples were found to be much higher than those in the blubber samples. The concentrations of butyltin compounds in blubber samples were observed to be related to their lipid content. Concentration levels of butyltin species in beluga whale were compared with those in other marine vertebrates in other parts of the world. The presence of butyltin compounds in liver and blubber samples suggests the accumulation of these toxicants by beluga whale. © 1998 John Wiley & Sons, Ltd.
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  • 86
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    Applied Organometallic Chemistry 12 (1998), S. 613-620 
    ISSN: 0268-2605
    Keywords: manganese oxides ; montmorillonite ; kaolinite ; mercury(II) ; methylation ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effects of freshwater sediment components such as kaolinite, montmorillonite and birnessite (δ-MnO2) on the biomethylation of mercury(II) in a synthetic growth medium (M-IIY) were assessed. Additions of kaolinite or montmorillonite to media containing mercuriC nitrate [Hg(NO3)2; 12 μg Hg ml-1] had no significant effect on either bacterial growth or the production of methylmercury (CH3Hg+). However, whereas the addition of birnessite resulted in only a small (ca 4%) increase in bacterial growth, it also produced a significant decrease (ca 50%) in the production of CH3Hg+. Further, it was demonstrated that, with the exception of kaolinite, adsorption of mercury(II) onto the sediment components before they were added to the M-IIY medium decreased its bioavailability, i.e., the amounts of CH3Hg+ produced from the adsorbed mercury(II) were significantly lower than those produced from equivalent concentrations of Hg(NO3)2 in the absence of the mineral colloids. In the case of montmorillonite, CH3Hg+ production was decreased by 21% relative to the control system. Most striking was the case of birnessite, in which no CH3Hg+ was detected after a 25 h incubation period and only very small quantities of CH3Hg+ (3-7 ng l-1) were present in the medium after 336 h. These data demonstrate that mineral colloids common in freshwater sediments significantly influence the extent of biomethylation of mercury(II) adsorbed on their surfaces. Birnessite, in particular, is a very effective inhibitor of the biomethylation of surface-bound mercury(II). Therefore, it may be possible to reduce the severity of mercury pollution in some aquatic environments by adding a reactive manganese oxide, such as birnessite, to the system and thereby to inhibit the transformation (methylation) of inorganic mercury(II) into the much more toxic CH3Hg+ species. © 1998 John Wiley & Sons, Ltd.
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  • 87
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    Applied Organometallic Chemistry 12 (1998), S. 621-634 
    ISSN: 0268-2605
    Keywords: quality ; phenytins ; mussel ; Certified Reference Material ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organotin contamination of the marine environment can be considered one of the main environmental problems in the last 20 years. Starting from the ‘Arcachon case’, monitoring campaigns have been carried out worldwide in order to evaluate the concentration levels of these compounds in the marine environment. In 1987 the EC Standards, Measurements and Testing Programme (formerly BCR) started a ‘tin speciation’ project to assess and improve the quality of measurements in this field and to make available reference materials. Ten years of study within the framework of this project have produced results in the fields of method development and production of reference materials, particularly for butyltins. The quality of the phenyltin analytical results was lower than for butyltins and further efforts are still needed. To overcome this shortfall, the last certification campaign was aimed towards the certification of phenyltins, as well as butyltins, in a candidate mussel certified Reference Material. The results of the homogeneity and stability tests for phenyltins and of the certification campaign are presented here. The preparation of the material and the analytical methods used in the certification campaigns are also described. The certification of phenyltins was hindered by their lack of long-term stability; nevertheless, the exercise provided information about the state-of-the-art of phenyltin measurements in biological samples. © 1998 John Wiley & Sons, Ltd.
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  • 88
    ISSN: 0268-2605
    Keywords: precursor ; ceramic ; thermolysis ; silicon ; carbodi-imide ; boron ; hydroboration ; plastic forming ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis, by two different reaction pathways, of boron-modified polysilylcarbodi-imides of general type {B[C2H4Si(R)NCN]3}n (R =­singly bonded organic ligand) and the plastic-forming and the thermal behavior of these polymers are described. Compounds {B[C2H4Si(R)NCN]3}n [2a, R = H; 2b, R = CH3; 2c, R = (NCN)0.5] can be obtained by treatment of the vinyl-substituted polysilylcarbodi-imides [(H2C=CH)(R)SiNCN]n [1a, R = H; 1b, R = CH3; 1c, R = (NCN)0.5] with borane dimethylsulfide BH3·S(CH3)2. The polysilylcarbodi-imides 1a-1c themselves are accessible via the reaction of vinyl-substituted chlorosilanes (H2C=CH)-­(R)SiCl2 with cyanamide H2N-C≡N in the presence of pyridine or by a non-oxide sol-gel process of vinylated chlorosilanes and bis(trimethylsilyl)carbodi-imide, (H3C)3SiN=C=NSi(CH3)3. In the second method for the synthesis of 2a-2c, hydroboration of vinyl-substituted chlorosilanes (H2C=CH)(R)SiCl2 with borane dimethylsulfide, borane trimethylamide or borane triethylamide to yield the tris[(chlorosilyl)ethyl]boranes B[C2H4Si(R)Cl2]3 (3a, R = H; 3b, R = CH3; 3c, R = Cl) is followed by treatment of the as-obtained compounds with bis(trimethylsilyl)carbodi-imide, which results in the formation of the hydroborated polysilylcarbodi-imides 2a-2c. The thermogravimetric behavior of the polymers 1a-1c and 2a-2c up to 2300°C is reported. It is shown that boron-modified polysilylcarbodi-imides are suitable precursors for the preparation of dense bulk ceramics. Therefore, the preparation of green bodies of the hydroborated polysilylcarbodi-imides 2a-2c by plastic forming (PF) is described. A series of experiments points to the fact that the microstructure of the as-obtained ceramic monoliths obtained by subsequent thermolysis of the plastic-formed green bodies is strongly influenced by the conditions during plastic forming. © 1998 John Wiley & Sons, Ltd.
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  • 89
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    Applied Organometallic Chemistry 12 (1998), S. 715-723 
    ISSN: 0268-2605
    Keywords: Cubic Silsesquioxanes ; interface ; materials ; hybrids ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cubic silsesquioxanes, [RSiO1.5]x, potentially offer access to organic/inorganic hybrids wherein the exact shape, size and mechanical properties of the inorganic component are perfectly defined. Furthermore, by tailoring the organic functionality bound to silicon, the inorganic/organic interface can also be perfectly defined. Finally, careful selection of the polymerizable groups in the organic moieties can provide good-to-excellent control of the crosslinked density or degree of polymerization of the resulting hybrid materials. Thus, cubic silsesquioxanes may be exceptional model materials for inorganic/organic hybrids. Methods of synthesizing cubes with liquid-crystalline and/or polymerizable organic moieties are described. Some thermal properties are discussed. The catalytic copolymerization of the octavinyldimethylsiloxy-functionalized cube with the octahydridodimethyl-­siloxy-functionalized cube to produce a material with well-defined microporosity and high surface area is described. © 1998 John Wiley & Sons, Ltd.
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  • 90
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    Applied Organometallic Chemistry 12 (1998), S. 675-680 
    ISSN: 0268-2605
    Keywords: polymer ; nanocomposites ; silicates ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymer nanocomposites, especially polymer-layered silicate (PLS) nanocomposites, represent a radical alternative to conventionally (macroscopically) filled polymers. Because of their nanometer-size dispersion, the nanocomposites exhibit markedly improved properties when compared with the pure polymers or conventional composites. These include increased modulus and strength, decreased gas permeability, increased solvent and heat resistance and decreased flammability. In addition to their potential applications, PLS nanocomposites are also unique model systems to study the structure and dynamics of polymers in confined environments. Using both delaminated and intercalated hybrids, the statics and dynamics of polymers confined over distances ranging from the radius of gyration of the polymer to the statistical segment length of the chains can be studied. © 1998 John Wiley & Sons, Ltd.
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  • 91
    ISSN: 0268-2605
    Keywords: polymer ; organocobalt ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rearrangement reaction of an organocobalt polymer with cobaltacyclopentadiene moieties in the main chain (1) was carried out to yield a­new polymer bearing (η5-cyclopentadienyl) (η4-­cyclobutadiene)cobalt moieties in the main chain (2). For instance, a polymer (2) containing pure η4-cyclobutadienecobalt units was obtained as a yellow powder in 79% yield by the reaction of 1 in tetrahydrofuran (THF) at 110 °C for 1 h in a sealed tube. The polymer (2) obtained was soluble in organic solvents such as chloroform, THF and N,N-dimethylformamide and was quite stable under air. It showed good thermal stability and a weight loss of 5% was observed at 482 °C by thermogravimetric analysis (TGA). On the other hand, displacement of the triphenylphosphine ligands on the main chain of the organocobalt polymer (1), without rearrangement of the cobaltacyclopentadiene rings, was observed when the reaction was carried out in the presence of appropriate ligands such as P(n-Bu)3. The resulting ligand-exchanged polymer showed different properties in comparison with 1. For instance a polymer bearing tri-n-octylphosphine is soluble in n-hexane, which is a poor solvent for 1. © 1998 John Wiley & Sons, Ltd.
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  • 92
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    Applied Organometallic Chemistry 12 (1998), S. 749-753 
    ISSN: 0268-2605
    Keywords: polymer ; silicon ; gel ; films ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of organic-inorganic polymer hybrids consisting of carbon-carbon and siloxane chains was investigated by radical polymerization of 3-methacryloxypropyltrimethoxysilane (MAS) followed by acid-catalyzed hydrolytic polycondensation. The condensation of poly(3-methacryloxypropyltrimethoxysilane) (S-PMA) of various molecular weights Mn =830-12000 prepared by polyaddition provided transparent and flexible free-standing hybrid gel films. The mechanical properties of these films were highly dependent on the carbon-carbon chain length: with an increase in the carbon-carbon chain length, the elasticity of gel films increased, while the tensile strength and Young's modulus decreased. Hydrolyzability of S-PMA decreased with an increase in the carbon-carbon chain length, resulting in the formation of rubber-like films with flexibility. © 1998 John Wiley & Sons, Ltd.
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  • 93
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    Applied Organometallic Chemistry 12 (1998), S. 755-762 
    ISSN: 0268-2605
    Keywords: poly(vinyl alcohol) (PVA) ; sol-gel ; polymer hybrid ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homogeneous poly(vinyl alcohol) (PVA)-silica gel polymer hybrids were prepared by in-situ hydrolysis of poly(vinyl acetate) (PVAc) in a sol-gel reaction mixture with tetramethoxysilane (TMOS). The degree of hydrolysis was evaluated by FTIR and 13C CP/MAS NMR; it increased with an increase in the acid catalyst and reached 85% with 1.6 ml of 0.1 M HCl. The homogeneity of the polymer hybrids obtained was maintained when the reaction was performed at 60 °C. However, the polymer hybrid became turbid with an increase of the amount of catalyst present when the reaction was conducted at room temperature. The homogeneity of the polymer hybrids obtained was evaluated by nitrogen sorption porosimetry of a porous silica that was obtained by charring the PVA hybrid. The results confirmed the molecular-level dispersion of the PVA in the hybrid. © 1998 John Wiley & Sons, Ltd.
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  • 94
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    Applied Organometallic Chemistry 12 (1998), S. 743-748 
    ISSN: 0268-2605
    Keywords: carbon black ; surface grafting of polymer ; polymer radical ; radical trapping ; azo-polymer ; peroxy-polymer ; electrical resistance ; poly(ethylene oxide) ; poly(ethylene imine) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The grafting of polymers onto a carbon black surface based on the trapping of polymer radicals by polycondensed aromatic rings of the surface was investigated. It was found that polymer radicals formed by the thermal decomposition of azo-polymer, peroxy-polymer and 2,2,6,6-tetramethylpiperidinyl-1-oxy-terminated polymer are successfully captured by a carbon black surface to give the corresponding polymer-grafted carbon blacks. The grafting of polymers onto carbon black was also achieved by the trapping of polymer radicals formed by the redox reaction of ceric ions with polymers having hydroxyl groups. It was concluded that surface grafting of polymers onto carbon black is effective when there are few functional groups. The electrical resistance of poly(ethylene oxide) (PEO)-grafted carbon black thus obtained is increased drastically to about 104-105 times the initial resistance at the melting point of PEO. This may be due to a widening of the gaps between the carbon black particles by melting of PEO. In addition, it was found that the electrical resistance of a crystalline poly(ethylene imine) (PEI)-grafted carbon black drastically increased to 103-104 times the initial resistance in methanol, ethanol and water vapor, but hardly any change in electrical resistance was observed in n-hexane or toluene vapor. These results suggest the possibility of detecting a slight change in the crystalline structure of PEI upon absorption of solvent vapor as a large increase in the electrical resistance of the polymer-grafted carbon black. © 1998 John Wiley & Sons, Ltd.
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  • 95
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    Applied Organometallic Chemistry 12 (1998), S. 1-12 
    ISSN: 0268-2605
    Keywords: reaction ; morin ; hydroxyflavone ; preconcentration ; sample clean-up ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analytical procedure for the determination of phenyltin compounds in environmental sample waters was studied. Chromatography of mono-, di- tri-phenyltin (MPT, DPT and TPT) was performed on a reversed-phase C18 column with the mobile phase comprising methanol/10-2 M H3PO4 (80:20 v/v) at pH 3 and UV detection at 214 nm. To enhance the sensitivity of the detection system, the post-column reaction between morin or 3-hydroxyflavone and phenyltin compounds was formed before fluorescence detection. Several parameters affecting the fluorescence intensity were studied systematically, including the optimum condition for the post-column reagent that was also compatible with the eluent. The parameters concerned in this study were the pH, the percentage of Triton X-100, the ratio of fluorigenic reagent to phenyltin compounds and the amount of methanol in the eluent. Detection limits before the preconcentration process were in the region of 1.5 ppb for TPT and 150-250 ppb for MPT and DPT, respectively. Utilizing solid-phase extraction on a C18 cartridge for sample clean-up as well as preconcentration successfully reduced the detection limit of TPT to the level of ng dm-3 and can be applied to seawater analysis. Recovery in the range 95.0-98.0% was obtained by developing the optimum elution profile in the preconcentration step. © 1998 John Wiley & Sons, Ltd.
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  • 96
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 97
    ISSN: 0268-2605
    Keywords: X ray structure ; triphenyltin ; p-ethoxybenzoic acid ; acetylsalicylic acid ; phthalic acid ; salicylaldehydato ; polymer ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenyltin(IV) compounds of p-ethoxybenzoic acid and acetylsalicylic acid contain molecular units with Sn-O bonds and distorted tetrahedral tin centers. The phthalic acid derivative contains two four-coordinate tin atoms between which the phthalic acid unit effectively forms a bridge. The salicylaldehydato compound is polymeric with trigonal bipyramidal tin centers in which the phenyl groups take equatorial positions. The polymerization occurs via the aldehyde oxygen atom bonding to a neighboring tin atom. © 1998 John Wiley & Sons, Ltd.
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  • 98
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    Applied Organometallic Chemistry 12 (1998), S. 25-30 
    ISSN: 0268-2605
    Keywords: adduct ; carboxylate ; Ceratocystis ulmi ; Dutch elm disease ; far-infrared spectroscopy ; fungicide ; Mossbauer spectroscopy ; organotins ; QSAR ; thiazolidin-4-ones ; triphenyltin ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the interest of developing a more effective fungicide to combat Dutch elm disease, our laboratories have synthesized several triphenyltin carboxylates and some 1:1 addition compounds of triphenyltin chloride using 2,3-disubstituted thiazolidin-4-ones as the ligand and screened them in vitro against Ceratocystis ulmi, the causative agent of Dutch elm disease, using a shake culture method. Elemental analyses and spectroscopic data indicate that the structures of the carboxy- lates in the solid state are monomeric with a tetrahedral tin atom with the exception of the furan-2-carboxylic acid derivative, which was found to be polymeric. The triphenyltin chloride adducts are trigonal-bipyramidal with the three phenyl groups in the equatorial plane. Far-infrared data indicate that the three phenyl groups are not co-planar. Screening results for both series of organotins indicate that these two classes of compounds are effective inhibitors of Ceratocystis ulmi, with the adducts having a higher activity. The furan-2-carboxylic acid derivative has a markedly decreased activity compared with the other carboxylates and this is attributed to its polymeric structure. © 1998 John Wiley & Sons, Ltd.
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  • 99
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    Applied Organometallic Chemistry 12 (1998), S. 78-78 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 100
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    Applied Organometallic Chemistry 12 (1998), S. 39-46 
    ISSN: 0268-2605
    Keywords: organotin(IV): organosilicon(IV) complexes ; thiosemicarbazones ; antimicrobial studies ; NMR spectra ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diorganotin(IV) and diorganosilicon(IV) derivatives of the types R2MCl(TSCZ) and R2M(TSCZ)2 (where TSCZ is the anion of a thiosemicarbazone ligand, R=Ph or Me and M=Sn or Si) have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding has been established on the basis of IR and 1H, 13C 29Si and 119Sn NMR spectroscopic studies. Some of the representative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria in vivoas well as in vitro.The results of these investigations are reported. © 1998 John Wiley & Sons, Ltd.
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