110,223 research outputs found
Festschrift Heinrich Müller-Breslau /
No full text-- Der starre elastisch gestützte Körper und seine Anwendung bei der geometrischen Behandlung mehrfach statisch unbestimmter Systeme / R. Skutsch.Includes bibliographical references.Ingenieur-Aufgaben / H. Boost -- Über den Windverband versteifter Hängebrücken / O. Domke -- Mitteilung über die Existenzbedingungen von reziproken Kräfteplänen ebener einfacher Fachwerke / M. Grübler -- Die Lösung linearer Gleichungen durch unendliche Reihen und ihre Anwendung auf die Berechnung hochgradig unbestimmter Systeme / A. Hertwig -- Über die Möglichkeit, n-punkte in der Ebene oder im Raume durch weniger als 2 n--3 oder 3 n--6 Stäbe von ganz unveränderlicher Länge unverschieblich miteinander zu verbinden / E. Kötter -- Über das Gleichgewicht elastischer Platten und langer Streifen / F. Kötter -- Zusatzspannungen infolge starrer Knotenverbindung / Th. Landsberg -- Das strebenlose Ständerfachwerk / L. Mann -- Zur Theorie statisch unbestimmter, hölzerner Dachbinder des Hochbaues / S. Müller -- Spannungen in Kugelschalen (Kuppeln) / H. ReissnerMode of access: Internet
Molsidomine attenuates N-omega-nitro-L-argininemethylester-induced deficits in a memory task in the rat
No full textThe present study was designed to investigate the role of nitric oxide (NO) on recognition memory in the rat. For this purpose, the effects on memory exerted by post-training administration of the NO synthase (NOS) inhibitor N-omega-nitro-L-argininemethylester (L-NAME) and the NO donor molsidomine were assessed by using the object recognition task. In a first dose-response study, L-NAME, at 30 but not at 10 mg/kg impaired the animals' performance, whereas at 60 mg/kg, it induced side-effects. Molsidomine, 4 mg/kg, antagonized the L-NAME-induced performance deficits. These results indicate that NO is involved in post-training memory processes
Spatial and temporal expressions of prune reveal a role in Müller gliogenesis during Xenopus retinal development
No full textThe development of stratified retinal cell architecture is highly conserved in all vertebrates, implying that a common fundamental molecular mechanism is involved in the generation of the organized retina. However, the detailed molecular mechanisms of retinal development are not fully understood. Here we have identified the Xenopus ortholog of prune and show that it is expressed in both differentiating and differentiated retinal domains during development. Interestingly, these spatial and temporal expression patterns coincide with the expression of prune binding partners, the NM23 family members. Overexpression of prune in retinal precur- sor cells significantly increases the ratio of Müller glial cells as observed by modulation of NM23 activity (Mochizuki et al., 2009). However, a mutated form of prune that has replacement of four aspartate (D) res- idues (D'Angelo et al., 2004), essential for phosphodiesterase activity, does not exhibit gliogenic activity. Our observations suggest that Xenopus prune may regulate Müller gliogenesis through phosphodiesterase- mediated regulation of NM23 family members
Tuning ultrafast electron injection dynamics at organic-graphene/metal interfaces
No full textThe properties of novel and prospective 2D materials are dramatically influenced by the interaction with a substrate. For example, the electronic hybridization of silicene states on Ag(111) or graphene ones on Ni(111) disrupts the Dirac fermions of the freestanding layers. This calls for efficient approaches to tune the interaction strength at the interface. Here we focus on the case of graphene functionalized by organic molecules and grown on Ni(111) and on the interfacial charge transfer dynamics. This is investigated by X-ray resonant photoemission spectroscopy, that is able to measure electron transfer rates occurring within few femtoseconds, and by a theoretical framework based on density-functional theory [1,2].
We use 4,4’-bipyridine as the prototypical molecule for these explorations as the energy level alignment of core-excited molecular orbitals allows ultrafast injection (τ=4fs) of electrons from the substrate to the molecule adsorbed on epitaxial graphene/Ni(111), which is characterized by a strong hybridization between C and metal states. We demonstrate that this interface can be decoupled by the addition of a second layer of graphene, where the one in contact with the metal acts as a buffer layer and the one in contact with the molecule is less hybridized with Ni underneath. As a result, the ultrafast injection of electrons from the substrate to the molecule is ∼4 times slower on weakly coupled bilayer graphene than on epitaxial graphene. Through our experiments and calculations, we can attribute this to a difference in the density of states close to the Fermi level between graphene and bilayer graphene. We therefore show how graphene coupling with the substrate influences charge transfer dynamics between organic molecules and graphene interfaces.
[1] G. Fratesi, C. Motta, M. I. Trioni, G. P. Brivio, and D. Sánchez-Portal, J. Phys. Chem. C 118, 8775 (2014)
[2] D. Cvetko, G. Fratesi, G. Kladnik, A. Cossaro, G.P. Brivio, L. Venkataraman, and A. Morgante, Phys. Chem. Chem. Phys. 18, 22140 (2016)
[3] A. Ravikumar, G. Kladnik, M. Müller, A. Cossaro, G. Bavdek, L. Patera, D. Sánchez-Portal, L. Venkataraman, A. Morgante, G. P. Brivio, D. Cvetko, and G. Fratesi, Nanoscale 10, 8014 (2018)
Improvement of an overloaded, multi-component, solvent gradient bioseparation through multiobjective optimization
No full textMüller-Weiss disease: Four case reports
No full textBACKGROUND Müller-Weiss disease (MWD) is an idiopathic foot condition characterized by spontaneous tarsal “scaphoiditis” in adults. Frequently bilateral and affecting females during the 4th-6th decades of life, the pathogenesis of MWD remains unclear: It has been traditionally considered a spontaneous osteonecrosis of the navicular. The typical presentation of MWD is a long period of subtle discomfort followed by prolonged standing, atraumatic, disabling pain. Currently, there is no gold standard for the treatment of patients with MWD. Most support initial conservative therapy. Operative treatment should be considered for failure of conservative therapies longer than 6 months. The indication for surgery is severity of symptoms rather than severity of deformities. Operative treatment options include core decompression, internal fixation of the tarsal navicular, open or arthroscopic triple fusion, talo-navicular or talo-navicular-cuneiform arthrodesis, and navicular excision with reconstruction of the medial column. CASE SUMMARY In this study, we report four patients affected by MWD. Clinical and radiographic assessment, follow-up and treatment are reported. CONCLUSION As it is frequently misdiagnosed, MWD is challenging for orthopedic surgeons. Early diagnosis and effective treatment are mandatory to avoid sequelae
Somatostatin withdrawal as generator of pulsatile GH release in the dog: a possible tool to evaluate the endogenous GHRH tone?
No full textReportedly, somatostatin (SS) withdrawal is an effective generator of pulsatile GH release in mammals and it has been proposed that the amplitude of the GH bursts is related to the functional activity of GHRH-producing neurons. Our study was designed to test this hypothesis in the unanesthetized dog, under different conditions of endogenous GHRH function. First, we evaluated the ability of withdrawal of SS infusion to induce a GH secretory burst under basal conditions when GHRH function is thought to be enhanced, i.e. in young (2- to 3-year-old) dogs under sustained (30 days) caloric restriction (CR) or a 2-day fast. Secondly, we performed experiments in aged (11- to 17-year-old) dogs, in which hypothalamic GHRH secretion is thought to be reduced. Old dogs were evaluated under basal conditions, after a 2-day fast and after a 10-day administration of GHRH alone or followed by fasting. Both before and 14 h after the end of each experimental period, young and old dogs underwent a 3-hour (from 10.00 to 13.00 h) intravenous SS infusion (4 mu g . kg(-1). h(-1)). The secretory profile of GH was generated by 15-min sampling from 09.00 to 15.00 h. Under baseline conditions, SS withdrawal induced a significant burst of GH in young but not in old dogs. After CR, termination of SS infusion was followed in young dogs by a robust GH burst, significantly higher than that observed when dogs were fed ad Libitum. In this instance, reduction of plasma IGF-I concentrations was unlikely to be responsible for the higher GH burst; the same pattern was present in the young dogs after a 2-day fast, when circulating IGF-I was unaltered. In old dogs, SS withdrawal did not modify baseline GH levels even after fasting, but induced a significant GH increase after GHRH priming. When GHRH priming was followed by fasting, SS withdrawal resulted in a GH burst higher than that occurring after fasting or GHRH alone. Altogether, these data support the view that the rebound rise in GH induced by withdrawal of SS is related to the endogenous GHRH tone. It is suggested that extrapolation of these findings to humans might permit probing, albeit inferentially, the endogenous GHRH tone under different physiologic or pathologic conditions
Evoluzione delle caratteristiche chimiche e sensoriali di vini bianchi Müller Thurgau imbottigliati con diverse tipologie di tappo
No full textIl binomio tappo-vino assume sempre più rilevanza grazie alla disponibilità/impiego di nuovi materiali finalizzati alla corretta conservabilità dei vini. In questo contesto una sperimentazione effettuata su Müller Thurgau ha monitorato l’evoluzione del vino imbottigliato con tre diverse tipologie di tappo nei nove mesi successivi all’imbottigliamento evidenziando peculiarità fisico-chimiche e sensoriali
Reconstructing reproductive life-histories in young girls. Assessment of the age-at-menarche in human mineralised tissues: a histological and bio-geochemical approach
No full textGrowth hormone responses to growth hormone-releasing hormone and hexarelin in fed and fasted dogs: effect of somatostatin infusion or pretratment with pirenzepine
No full textUsing unanesthetized young male and female beagle dogs, before and after a 2-day fast, we studied that effect of an i.v. infusion of 0.9% saline (5 ml/h), somatostatin (SS, 4 or 8 μg/kg/h) or pretreatment with pirenzepine (PZ, 0.6 mg/kg i.v.), a muscarinic cholinergic antagonist which allegedly releases SS, on the GH release evoked by acute administration of GHRH (2 μg/kg i.v.), hexarelin (HEXA), a member of the GH-releasing peptide family (250 μg/kg i.v.) or GHRH plus HEXA. In fasted dogs, GHRH delivered during saline infusion induced a clear-cut rise in plasma GH levels, significantly higher than that which it induced in fed dogs. In contrast, HEXA, although very effective in causing the release of GH, only slightly increased GH secretion in fasted dogs over that which it induced in fed dogs. Co- administration of GHRH plus HEXA into fed dogs induced a synergic GH response that further increased with fasting. The action of GHRH in fed dogs was abolished by the lower dose of SS, whereas SS at either dose was ineffective in suppressing the GH-releasing effect during fasting. Infusion of the lower dose of SS failed to counter the action of HEXA, either before or during fasting, whilst the higher SS dose partially reduced it in both conditions. In contrast to SS, PZ reduced the GH-releasing effect of GHRH and HEXA, both in the fed state and, though to a lesser extent, during fasting. Pirenzepine only slightly reduced the robust GH rise elicited by GHRH plus HEXA in fed dogs. The suppressive effect of PZ on the GH response to combined administration of the peptides was lowest in fasted dogs. These data show that: (1) fasting augmented the GH response to GHRH and (to a lesser degree) to HEXA; (2) SS inhibited the GH response to GHRH in the fed state, but not in the fasted state; (3) only the higher dose of SS partially reduced the GH stimulation by HEXA in either the fed or the fasted state; (4) PZ lowered the GH response to GHRH and to HEXA in both the fed and (to a lesser degree) the fasted state; (5) PZ did not modify the GH release due to the combined administration of GHRH and HEXA. It is suggested that: (1) during fasting the greatly enhanced GH response to GHRH alone or GHRH plus HEXA probably reflects an augmented GHRH secretion; (2) somatotrope refractoriness to SS may contribute to the enhanced GH secretion in states of caloric deprivation; (3) in contrast to a general belief, muscarinic cholinergic antagonists, e.g. PZ, do not act exclusively via release of SS, but probably also through inhibition of GHRH function
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