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  • 1
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    German Medical Science; Düsseldorf, Köln
    In:  121. Kongress der Deutschen Gesellschaft für Chirurgie; 20040427-20040430; Berlin; DOC04dgch1023 /20041007/
    Publication Date: 2004-10-07
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 2
    ISSN: 1432-0630
    Keywords: PACS: 77.65.-j; 77.84.Jd; 85.50.+k
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Large piezoelectric d33 coefficients around 600 pC/N are found in corona-charged non-uniform electrets consisting of elastically “soft” (microporous polytetrafluoroethylene PTFE) and “stiff” (perfluorinated cyclobutene PFCB) polymer layers. The piezoelectric activity of the two-layer fluoropolymer stack exceeds the d33 coefficient of the ferroelectric ceramic lead zirconate titanate (PZT) by more than a factor of two and that of the ferroelectric polymer polyvinylidene fluoride (PVDF) by a factor of 20. Soft piezoelectric materials may become interesting for a large number of sensor and transducer applications, in areas such as security systems, medical diagnostics, and nondestructive testing.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The molecular mechanisms underlying cell cycle control in neuronal progenitors have been investigated with adult mouse olfactory epithelium as a model system. Odorreceptive neurons of mammalian olfactory epithelium are short-lived and renewed in the adult by mitotic division of intrinsic neuronal progenitors. Ablation of the synaptic target, olfactory bulb, induces sequentially extensive apoptosis of sensory neurons and then stimulation of progenitor proliferation, peaking at 36 h and 4 days, respectively, postlesion. Known molecular effectors of G1 phase entry have been assessed on protein extracts of olfactory organs sampled at various postbulbectomy times in adult mice. The decay of βIII-tubulin and olfactory marker protein levels and the rise of proliferating cell nuclear antigen (PCNA) levels, starting 1 and 3 days, respectively, postlesion, provided the kinetic frame of neuronal dynamics. Cyclin D1, cyclin E, and cyclin-dependent kinase cdk2 levels, low in olfactory organ of intact mice, increased 3 days after bulbectomy in parallel with PCNA levels; cdk4 content was initially high and unaffected by lesioning. Western blots of the known cdk inhibitors revealed proliferation-related decreases of p18, p21, and p27 from high expression in intact organs. Immunoprecipitation of cdk2 and cdk4 fractions of protein extracts at 4 days postlesion (mitotic reaction peak) versus control, followed by cyclin D1 immunoblotting, and vice versa, revealed that levels of both cyclin D1/cdk2 and cyclin D1/cdk4 complexes, as well as their kinase activities, were dramatically increased after lesion. In vivo proliferation of olfactory neuronal lineage cells thus involves functional binding of cyclin D1 with cdk2 and cdk4, with differential activation mechanisms for cdk2 and cdk4. In addition, the RT-PCR-detected cyclin D1 mRNA level remained unaffected after bulbectomy, which indicated that the cyclin D1 rise should involve posttranscriptional mechanisms in this in vivo neuronal system. These observations are discussed, along with their relevance to cell cycle control and to olfactory neuron dynamics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0044-281X
    Keywords: Schlüsselwörter Aortenklappenersatz – Letalität – Morbidität –¶Überleben – 9. Lebensdekade ; Key words Aortic valve replacement – mortality – morbidity –¶survival – 9th decade of life
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Due to demographic changes in average life expectancy, the age of patients undergoing cardiac surgery is increasing as well. We have reviewed the short- and long-term outcome in patients over 80 years of age after aortic valve replacement.¶   From 01Jan1995 until 31Dec1998, 105 patients (76 women, 29 men between 80 and 89 years, median: 83) underwent aortic valve replacement. 42% presented with aortic stenosis, 58% with combined valve disease with leading stenosis. 53% (group A) received isolated valve replacement, 47% (group B) underwent myocardial revascularization as well. The in-hospital mortality rate was 8.9% for group A and 14.3% for group B. The follow-up time ranged between 10 and 243 weeks (median: 112 weeks). None of the patients had to be reoperated for prosthetic valve dysfunction or endocarditis. Bleeding complications due to anticoagulant therapy were not observed. Of the 11 deaths during the follow-up period, 5 (45%) were cardiac in nature and 2 (18%) related to stroke. Actuarial survival rates for group A were 98, 95 and 88% at 1, 2 and 3 years, and for group B 92, 84 and 84%, respectively. Permanent nursing care was not required 1 year after the operation by 98% of patients in group A (2 years: 95%, 3 years: 88%) and by 100% of patients in group B (2 years: 95%, 3 years: 88%). At an interval of 1 year after the operation 98% of patients in group A had not been hospitalized as a result of cardiac disorders ¶(2 years: 98%, 3 years: 94%). The rates for group B were 90, 82 and 82%.¶   Compared with younger age groups, aortic valve replacement in patients 80 years of age and older is associated with a distinctly increased mortality and morbidity. However, our data suggest that considering the poor prognosis of conservative therapy of symptomatic aortic valve disease, the functional status as well as life expectancy in this age group seems to be positively influenced by aortic valve replacement.
    Notes: Zusammenfassung Mit zunehmendem Anteil älterer Menschen an der Gesamtbevölkerung nimmt das durchschnittliche Alter der am Herzen operierten Patienten zu. Wir haben in unserem Patientengut die Kurz- und Langzeitergebnisse des Aortenklappenersatzes in der neunten Lebensdekade untersucht. Zwischen dem 1.1.1995 und dem 31.12.1998 wurden 105 Patienten (76 Frauen, 29 Männer, 80 bis 89 Jahre alt, Median: 83 Jahre) einem Aortenklappenersatz unterzogen. 42% hatten eine Aortenstenose, 58% ein kombiniertes Vitium mit führender Stenose. Bei 53% wurde ein isolierter Klappenersatz vorgenommen (Gruppe A), 47% erhielten zusätzlich eine Myokardrevaskularisation (Gruppe B). Die Krankenhausletalität betrug bei isoliertem Klappenersatz 8,9% und bei Kombinationseingriffen 14,3%. Die Nachbeobachtungszeit betrug zwischen 10 und 243 Wochen (Median: 112 Wochen). Reoperationen wegen Prothesendysfunktion oder -endokarditis sowie Blutungen aufgrund der Antikoagulation wurden nicht beobachtet. Von den 11 Todesfällen während der Nachbeobachtungsphase waren 5 (45%) kardial bedingt und 2 (18%) Folge eines Schlaganfalls. Die Überlebensrate betrug bei Patienten der Gruppe A nach einem Jahr 98%, nach zwei Jahren 95% und nach drei Jahren 88%. Für die Gruppe B waren die entsprechenden Zahlen 92, 84 und 84%. Die Freiheitsrate von Pflegebedürftigkeit war beim isolierten Aortenklappenersatz nach einem Jahr 98%, nach zwei Jahren 95%, nach drei Jahren 88% und bei Kombinationseingriffen 100, 95 und 88%. Die Freiheitsrate von erneuter stationärer Behandlung aus kardialen Gründen war in der Gruppe A nach einem Jahr 98%, nach zwei Jahren 98%, nach drei Jahren 94% und in der Gruppe B 90, 82 sowie 82%.¶  Der Aortenklappenersatz ist bei Patienten in der neunten Lebensdekade im Vergleich zu jüngeren Patienten mit einer deutlich erhöhten Letalität und Morbidität verbunden. Berücksichtigt man jedoch die infauste Prognose der konservativen Therapie klinisch manifester Aortenvitien, so weisen unsere Daten darauf hin, dass auch im hohen Alter der funktionelle Status und die Lebenserwartung durch den Klappenersatz positiv beeinflusst werden können.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 72 (1950), S. 1864-1864 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 75 (1953), S. 1004-1005 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Charged closed-cell microporous polypropylene foams are shown to exhibit piezoelectric resonance modes in the dielectric function, coupled with a large anisotropy in the electromechanical and elastic material properties. Strong direct and converse dynamic piezoelectricity with a piezoelectric d33 coefficient of 140 pC/N at 600 kHz is identified. The piezoelectric d33 coefficient exceeds that of the ferroelectric polymer polyvinylidene fluoride by a factor of 5 and compares favorably with ferroelectric ceramics. Applications of similar concepts should provide a broad class of easily fabricated "soft" piezoelectric materials. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 75 (1953), S. 1003-1004 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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