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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 10 (1988), S. 915-932 
    ISSN: 0392-6737
    Keywords: Quantum effects on the structure and dynamics of nondegenerate fluids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto In questo lavoro si applica la teoria della matriceU per dedurre un'espressione esplicita per lo spettro d'energia di eccitazione dell'4He liquido. Usando un modello per il potenziale chimico efficace per l'4He si è in grado di produrre uno spettro di eccitazione molto simile a quello osservato. L'inverso della massa efficace, cioè 1/m *, è ottenuto in funzione del momentok. Si trova che il rapporto tra massa efficace e la massa dell'atomo di elio ak=2.0 Å−1, cioè vicino alla profondità del rotore, èm * (k=2.0 Å−1)/m He= =0.18298, mentre quello ak=1.0 Å−1 èm * (k=1.0 Å−1)/m he=−0.17103. Il risultato teorico dello spettro di eccitazione è coerente con i dati sperimentali.
    Abstract: Резюме В этой статье мы применяем теориюU-матрицы для вывода явного выражения для энергетического спектра возбуждений Зидкого4He. Используя модель для эффективного химического потенциала для4He, мы воспроизводим спектр возбуждений который оказывается очень близким к зкспериментально наблюдаемому. Вычисляется обратная величина эффективной массы, т.е. 1/m *, как функция импульсаk. Получено отношение эффективной массы к массе атома гелия приk=2.0 Å−1, которое составляетm * (k=2.0 Å−1)/m He=0.18298, тогда как это отношение приk=1.0 Å−1 равноm * (k=1.0 Å−1)/m He=−0.17103. Теоретический результат для спектра возбужений согласуется с имеющимися экспериментальными данными.
    Notes: Summary In this paper, we apply theU-matrix theory to derive an explicit expression for the excitation energy spectrum of liquid4He. Using a model for the effective chemical potential for4He, we are able to produce an excitation spectrum which is very close to the observed one. The inverse of the effective mass,i.e. 1/m *, is obtained as a function of momentumk. The ratio between the effective mass and the mass of helium atom atk=2.0 Å−1,i.e. near the roton depth, is found to bem *(k=2.0 Å−1)/m He=0.18298, while the ratio atk=1.0 Å−1 ism *(k=1.0 Å−1)/m He=−0.17103. The theoretical result of the excitation spectrum is consistent with observational data.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 10 (1988), S. 247-276 
    ISSN: 0392-6737
    Keywords: Boson degeneracy and superfluidity of helium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Impiegando la teoria della matriceU nella forma presente, abbiamo presentato una teoria microscopica di un sistema interagente diN bosoni a temperatura non nulla. L'hamiltoniana include un termine che descrive l'influenza esterna, un termine per un'interazione a 2 particelle e une che riguarda l'interazione di tipo dipolare. Per studiare lo stato fondamentale dell'4He liquido s'include solo l'interazione a 2 particelle. Basandoci su dati di scattering, abbiamo dedotto la funzione potenziale a 2 particelle. Con quella, calcoliamo numericamente la distribuzione dell'impulso aT=1.1K per diversi gruppi di parametri. Si mostra che le curve teoriche sono in buon accordo con i risultati osservati. Le corrispondenti curve del fattore di struttura del liquido si adattano benissimo ai dati misurati e il risultato migliore per l'energia dello stato fondamentale è − 7.12K.
    Abstract: Резюме Используь теориюU-матрицы, мы предлагаем микроскопическую теорию взаимодеюствующейN-бозонной системы при ненулевых температурах. Гамильтониан включает член, описывающий внешнее влияние, член двух-частичного взаимодействия и член, относящийся к дипольному типу взаимодействия. При исследовании основного состояния шидкого4He учитяватся только двух-частичное взаимодействие. Основываясь на данных по рассеянию, мы выводим двух-частичную потенциальную функцию. Мы численно определяем распределение по импульсам приT=1.1K для некоторых систем параметров. Показывается, что теоретические кривые согласуются с наблюденными результатами. Соответст вующий структурный фактор зидкости хорошо согласуется с экспериментальными данными. Полученная величина энергии основного состояния составляет −7.12 K.
    Notes: Summary Employing theU-matrix theory in the present form we have presented a microscopic theory of an interactingN-boson system at nonzero temperature. The Hamiltonian includes a term describing the external influence, a term for a two-particle interaction and one pertaining to the dipole-type interaction. To study the ground state of liquid4He, only the two-particle interaction is included. Based on scattering data, we have deduced the two-particle potential function. With that we calculate numerically the momentum atT=1.1 K for several sets of parameters. It is shown that the theoretical curves agree well with the observed results. The corresponding liquid-structure-factor curves fit the measured data very well and the best result for the ground-state energy is −7.12K.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 511 (1987), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Notes: The glycosylated and the non-glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (rh GM-CSF) expressed in Chinese hamster ovary cells and E. coli, respectively, were administered in rhesus monkeys either by the subcutaneous (three times daily) or intravenous route (6-hr infusions) for seven consecutive days. Within 24 hr peripheral white blood cells (WBC) increased 2-3-fold over normal values. Thereafter, the WBC increased steadily in a dose-dependent manner to reach maximum levels on the last day of or one day after the treatment period. The differential counts showed that neutrophils contributed to 50-80%, eosinophils to 10-20%, monocytes to 2-7%, and lymphocytes to 15–30% of the WBC rise. No effect was found on platelets and erythrocytes. After termination of treatment, WBC counts returned to normal levels within one week. Subcutaneously administered CSF was more effective in inducing leukocytosis than that injected intravenously. In addition to the rise in WBC, the administered rh GM-CSF also enhanced the oxidative metabolism and bactericidal activity of the circulating mature granulocytes isolated from the blood of monkeys treated with rh GM-CSF. These results show that glycosylated or non-glycosylated rh GM-CSF is both an effective stimulator of leukocytosis and a potent activator of the functional activity of mature granulocytes in vivo.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical microbiology & infectious diseases 4 (1985), S. 279-281 
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In an attempt to inhibit the biosynthesis of the type-specific M protein usually expressed on surface fimbriae group AStreptococcus pyogenes Δ 2305 was cultivated in Todd-Hewitt broth containing 10 % human serum and subinhibitory concentrations of either josamycin, erythromycin or clindamycin. Electron microscopy revealed that the antibiotic-pretreatment had little visible effect on the surface structures of the streptococci. However, josamycin and clindamycin-pretreated bacteria adhered less to hydrophobic gels than erythromycinpretreated or untreated control cultures. Due to the decrease in surface hydrophobicity, the drug-pretreated bacteria also activated complement more readily and fixed more C3 on their surface. Consequently the killing of josamycin and clindamycin-pretreated bacteria by polymorphonuclear leucocytes was significantly enhanced. Similar findings were obtained when the M protein was removed from the bacteria by digestion with trypsin. These results suggest that josamycin, like clindamycin, reverses the capacity of group A streptococci to resist opsonization by normal human serum and interferes with the adhesion of the organisms to host epithelial cell surfaces.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1439-0973
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die komplementbedingte Opsonierungsaktivität (CMOA) in Intraabdominalexsudaten, gewonnen während der Laparotomie von Peritonitispatienten, wurdein vitro an einem Phagozytosemodell untersucht. Es zeigte sich, daß infektiöse Intraabdominalexsudate die Abtötung vonEscherichia coli O1 durch polymorphkernige Leukozyten kaum fördern. Bakterien, mittels Differentialzentrifugation aus infizierten Exsudaten gewonnen, wiesen nur zu einem geringen Teil C3 auf ihrer Oberfläche auf. Diese Organismen wurdenin vivo nicht optimal opsoniert, während siein vitro nach kurzer Inkubationszeit in normalem Humanserum mit C3 vollständig beladen werden konnten. Der geringe Gehalt an C3 im Peritoneum kommt einer Verringerung von Komplement im Blut gleich. Dementsprechend war die CMOA bei Septikämien, bedingt durch gramnegative Organismen, extrem niedrig. Die Ergebnisse lassen vermuten, daß die hohe Anfälligkeit des Peritoneums für Infektionen durch Keime der Darmflora zum Teil mit dem niedrigen Gehalt an Komplement erklärt werden kann, der eine ausreichende Opsonierung der Bakterien nicht gewährleistet.
    Notes: Summary The complement-mediated opsonic activity (CMOA) in intra-abdominal exudates collected during laparotomy from peritonitis patients was examined by anin vitro phagocytic bactericidal assay. It was found that infected intra-abdominal exudates barely promoted detectable killing ofEscherichia coli 01 by polymorphonuclear leukocytes. Only the minority of bacteria recovered by differential centrifugation from the infected exudates had C3 on their surfaces. Such bacteria were not optimally opsonizedin vivo, whereas they became fully coated with C3 during a brief incubationin vitro in normal human serum. The low level of CMOA in the peritoneal fluid paralleled a depletion of complement in the peripheral blood. Thus, in cases complicated by sepsis with gram-negative bacteria, the CMOA in the blood was extremely low. These data suggest that the high susceptibility of the peritoneum to infection by gut flora, despite the normal phagocytic response, may be partly explained by the low local level of functional complement which is inadequate for optimal opsonization of the bacteria.
    Type of Medium: Electronic Resource
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