Förster-type energy transfer. Simultaneous 'forward' and 'reverse' transfer between unlike fluorophores

The general case of F?rster-type energy transfer is that in which energy is exchanged in both directions between two unlike fluorophores. In such cases, energy is transferred from the conventionally defined donor to the conventionally defined acceptor (forward transfer) and at the same time from the acceptor to the donor (reverse transfer). Expressions are derived to describe the fluorescence intensities and lifetimes of fluorophores undergoing simultaneous forward and reverse transfer; these are compared with corresponding quantities for the case more usually considered, in which only forward transfer is significant. It is shown that the presence of reverse transfer removes the distinction between donor and acceptor, and allows such anomalous effects as 'acceptor quenching'. A confirmatory example is described. It is shown that the equations generally used in distance determination by steady-state fluorescence spectroscopy can also be applied in the presence of reverse transfer, if a correction term is included; however, for lifetime spectroscopy the correction is more complex.     

Anthocyanins and xanthones in the calli and regenerated shoots of Hypericum perforatum var. angustifolium (sin. Fröhlich) Borkh

The present paper reports on the production of anthocyanins and xanthones in different in vitro systems of Hypericum perforatum var. angustifolium (sin. Fröhlich) Borkh. Undifferentiated calli and regenerated shoots at different developmental stages were analyzed by applying an extractive and an analytical procedure capable of detecting and quantifying anthocyanins. The findings revealed, for the first time, the co-presence of hypericins and anthocyanins in shoots at initial and more developed stages of H. perforatum var. angustifolium L. Moreover, a high production of xanthones was found in the undifferentiated calli.     

Dynamic restoration in Möbius and Möbius-like patients

M?bius syndrome is classically characterized by bilateral facial nerve and abducens nerve paralysis in combination with limb defects. In the past 110 years, physicians diagnosed children as having the syndrome on the basis of heterogeneity of symptoms and used the term "M?bius syndrome" or "M?bius-like syndrome" for patients with multiple cranial nerve involvement. The cause and the exact pathogenesis of the syndrome still elude understanding. Genetic work-ups, radiological findings, and data from autopsies differ in their approaches and their findings of the basic causes of M?bius syndrome. In the international literature, about 301 case reports are found scattered through the past century. The appearance of the facial deformity is easy to recognize, because the M?bius patient is impaired in his or her ability to communicate nonverbally. Despite ophthalmologic problems, it is the search for a smile that brings these patients to the reconstructive surgeon. Over the past 100 years, surgical efforts attempted to improve the mask-like appearance by static and dynamic procedures, usually local muscle transpositions. Today, combinations of microsurgical procedures and aesthetic techniques are being used to restore some movement to the expressionless face of these patients by nerve and muscle transplantation. This article discusses the heterogeneity of M?bius syndrome, advocates a new classification system, presents the clinical findings of 42 patients who were seen and examined in consultation, and discusses the surgical management of 20 patients who underwent dynamic restorative microsurgery. Exemplary cases illustrating the preoperative work-up regimen and possible outcomes are reported.     

Das Gynözeum der Bignoniaceen. II. Die U-förmige Plazenta vonSchlegelia (Crescentieae)

Zusammenfassung Die GattungSchlegelia, von derS. lilacina, parasitica, nicaraguensis undspruceana an Hand von Herbarmaterial untersucht wurden, besitzt in ihrem Fruchtknoten typische U-förmige Plazenten. Die getrennten Plazentenschenkeln des plikaten Abschnittes der Karpelle vereinigen sich im ascidiaten Abschnitt zu einem ansehnlichen und median inserierten Plazentenwulst, dessen ganze Oberfläche Samenanlagen trägt. Damit aber weicht das Gynözeum vonSchlegelia von jenem aller anderen Bignoniaceen beträchtlich ab und gleicht völlig jenem der meisten Scrophulariaceen, so daß vielleicht an eine Überführung der GattungSchlegelia zu den Scrophulariaceen zu denken ist.     

Orthotrichum lewinskyae sp. nov. (Orthotrichaceae,Musci), a Moroccan epiphytic moss related to O. scanicum Grönv. and o. holmenii Lew.-Haap

Abstract

A new species of Orthotrichum (O. lewinskyae) from the Rif Cordillera and the Mid Atlas Mountains (Morocco) is described. This taxon is included in subgenus Pulchella (Schimp.) Vitt section Pulchella Schimp. It is close to O. scanicum Grönv. and o. holmenii Lew.-Haap., from which it differs by the following combination of characters: large spores (22–30 μm); leaves linear-Ianceolate with wide and excavate at bases; leaf margins progressively narrowed at apices, which can be plane or incurved on one or both sides; upper leaf-cells larger than those of related taxa; seta intermediate between those of O. scanicum and o. holmenii.