Urea oxidation electrocatalysis on nickel hydroxide: the role of disorder

Journal of Solid State Electrochemistry - The urea oxidation reaction (UOR) is an important challenge in electrocatalysis, in the context of electrolyzers, fuel cells, medical sensing, and...     

Untersuchung von Harn, Blut und sonstigem biologischen Material

Ohne Zusammenfassung     

Über die Primfunktionen in einer arithmetischen Progression

Ohne ZusammenfassungVerfasser, geboren in Wohlau am 23. August 1890, hatte vor dem Kriege selbständig die Entdeckung gemacht, daß Dirichlets klassischer Beweis des Satzes von den Primzahlen einer arithmetischen Progression (nebst den späteren elementaren Begründungen des Nichtvershwindens der bekannten Reihen) ein Analogon z. B. in der Theorie der Primfunktionen in Restklassen nach einem Doppelmodulp, M hat. Über dies selbstgewählte Thema hatte er seine Doktordissertation im wesentlichen schon fertiggestellt. Als Kriegsfreiwilliger fiel er im Oktober 1914 bei Poël-Capelle. Erst kürzlich erhielt ich aus seinem Nachlaß das (mir schon seit 1914 bekannte) Manuskript. Ich übergebe hiermit die schönsten und interessantesten Teile der Öffentlichkeit. Der Kornblumsche Ansatz zeichnet sich durch hohe Eleganz aus und zeigt, daß die Wissenschaft in ihm einen hoffnungsvollen Forscher verloren hat. Den Satz und Beweis des § 1 habe ich aus Kornblums Manuskript übernommen; einige Bemerkungen habe ich in Fußnoten angefügt. Den Satz und Beweis des § 2 hat er allerdings nur fürk=2 gehabt; doch wäre die von mir hinzugefügte Ausdehnung auf beliebigesk wohl ohnebin bei gemeinsamer Besprechung in seiner Dissertation hinzugekommen, da alles unmittelbar mit seiner Methode herauskommt.     

Qualitative Analyse

Ohne Zusammenfassung     

Reactions of 2-nitro-2-(4-pyridyl) propane with nucleophiles. Substitution at tertiary carbon

The reaction of 2-nitro-2-(4-pyridyl) propane (I) with lithium 2-propanenitronate, lithium cyclohexanenitronate, and sodium thiophenoxide affords excellent yields of the C-alkylation products 2-nitro-3-(4-pyridyl)-2,3-dimethylbutane (II), 2-(4-pyridyl)-2-(1-nitrocyclohexyl) propane (V) and 2-thiophenyl-2-(4-pyridyl) propane (VI), respectively. In contrast, the reaction of compound I with sodium azide does not afford the expected tertiary azide; but instead gives the dimer 2,3-bis(4-pyridyl)-2,3-dimethylbutane (III), in near quantitative yield. Evidence has been obtained that all of these transformations proceed via electron transfer pathways.     

Loudness perception and frequency discrimination in subjects with steeply sloping hearing loss: possible correlates of neural plasticity.

Loudness functions and frequency difference limens (DLFs) were measured in five subjects with steeply sloping high-frequency sensorineural hearing loss. The stimuli were pulsed pure tones encompassing a range of frequencies. Loudness data were obtained using a 2AFC matching procedure with a 500-Hz reference presented at a number of levels. DLFs were measured using a 3AFC procedure with intensities randomized within 6 dB around an equal-loudness level. Results showed significantly shallower loudness functions near the cutoff frequency of the loss than at a lower frequency, where hearing thresholds were near normal. DLFs were elevated, on average, relative to DLFs measured using the same procedure in five normally hearing subjects, but showed a local reduction near the cutoff frequency in most subjects with high-frequency loss. The loudness data are generally consistent with recent models that describe loudness perception in terms of peripheral excitation patterns that are presumably restricted by a steeply sloping hearing loss. However, the DLF data are interpreted with reference to animal experiments that have shown reorganization in the auditory cortex following the introduction of restricted cochlear lesions. Such reorganization results in an increase in the spatial representation of lesion-edge frequencies, and is comparable with the functional reorganization observed in animals following frequency-discrimination training. It is suggested that similar effects may occur in humans with steeply sloping high-frequency hearing loss, and therefore, the local reduction in DLFs in our data may reflect neural plasticity.