Double reinsertion including Whitnall's ligament in aponeurotic ptosis surgery : Comparison of results following simple aponeurosis reinsertion surgery and a combined reinsertion of the aponeurosis to Whitnall's ligament for aponeurotic palpebral ptosis: a cohort study of 722 cases.

PURPOSE: The results of a technique with a double reinsertion of the aponeurosis to the tarsus and aponeurosis to Whitnall's ligament (ATW) were compared with a simple reinsertion of the aponeurosis to the tarsus (AT) in acquired aponeurotic palpebral ptosis surgery. METHODS: Analytical, observational, retrospective, cohort study. Seven hundred and twenty-two consecutive cases with acquired aponeurotic palpebral ptosis have been treated surgically between 2000 and 2012 and have been followed up for 5 years. The cases were divided into two cohorts according to the applied surgical technique (AT vs ATW). RESULTS: The mean postoperative MRD after 1 month in cohort AT was 1 mm lower than in ATW (3 ± 0.9 mm vs 4 ± 1 mm). The mean MRD in the long-term follow-up (5 years) was 1 mm lower in cohort AT than in ATW (2.9 ± 1.5 mm vs 3.9 ± 0.9 mm). The rate of long-term recurrence (5 years) was 15% higher in A-T than in A-T-W (20% vs 5%). 70.5% of the eyes studied intra-surgically presented gaps between the Whitnall ligament and the aponeurosis, an anatomical area that we describe as the upper transition zone (UTZ). In an independent analysis, only those patients with open UTZ were evaluated and it was observed that those operated with A-T-W presented elevations greater than 1 mm compared to those operated with the AT technique (4 ± 0.9 mm A-T-W vs 2.8 ± 1 mm A-T) and a much lower recurrence rate (5.4% A-T vs 38.09% A-T-W). CONCLUSIONS: In our study, the A-T-W technique achieved better results in terms of palpebral elevation and fewer recurrences compared to the A-T technique in all cases studied with aponeurotic ptosis. However, it particularly demonstrates its superiority in patients with large gaps in the UTZ.

Observation of Room-Temperature Photoluminescence Blinking in Armchair-Edge Graphene Nanoribbons.

By enhancing the photoluminescence from aligned seven-atom wide armchair-edge graphene nanoribbons using plasmonic nanoantennas, we are able to observe blinking of the emission. The on- and off-times of the blinking follow power law statistics. In time-resolved spectra, we observe spectral diffusion. These findings together are a strong indication of the emission originating from a single quantum emitter. The room temperature photoluminescence displays a narrow spectral width of less than 50 meV, which is significantly smaller than the previously observed ensemble line width of 0.8 eV. From spectral time traces, we identify three optical transitions, which are energetically situated below the lowest bulk excitonic state E11 of the nanoribbons. We attribute the emission to transitions involving Tamm states localized at the end of the nanoribbon. The photoluminescence from a single ribbon is strongly enhanced when its end is in the antenna hot spot resulting in the observed single molecule characteristics of the emission. Our findings illustrate the essential role of the end termination of graphene nanoribbons in light emission and allow us to construct a model for photoluminescence from nanoribbons.

[Chronic Progressive External Ophthalmoplegia Ptosis: Problems with Diagnostics and Treatment]. / Ptosis bei chronisch progressiver externer Ophthalmoplegie: diagnostische Probleme und therapeutische Konsequenzen.

Ptosis is often the first symptom of chronic progressive external ophthalmoplegia (CPEO), a rare muscle disorder. As the disease progresses, it can lead to ocular motility defects. Ptosis is present in the early stages of the disease and can be corrected by levator surgery. Due to the rarity of CPEO (< 1% of ptosis patients), further diagnostic steps with muscle biopsy and genetic analysis of mitochondrial DNA are usually not considered in the early phase. Intraoperative abnormal observations during ptosis surgery and postoperative motility problems are signs of CPEO. If CPEO is confirmed, alternative surgical methods can correct the ptosis, like frontalis suspension.

Eleven nanometer alignment precision of a plasmonic nanoantenna with a self-assembled GaAs quantum dot.

Plasmonics offers the opportunity of tailoring the interaction of light with single quantum emitters. However, the strong field localization of plasmons requires spatial fabrication accuracy far beyond what is required for other nanophotonic technologies. Furthermore, this accuracy has to be achieved across different fabrication processes to combine quantum emitters and plasmonics. We demonstrate a solution to this critical problem by controlled positioning of plasmonic nanoantennas with an accuracy of 11 nm next to single self-assembled GaAs semiconductor quantum dots, whose position can be determined with nanometer precision. These dots do not suffer from blinking or bleaching or from random orientation of the transition dipole moment as colloidal nanocrystals do. Our method introduces flexible fabrication of arbitrary nanostructures coupled to single-photon sources in a controllable and scalable fashion.

A tyrosine aminotransferase involved in tocopherol synthesis in Arabidopsis.

The metabolic function of the predicted Arabidopsis tyrosine aminotransferase (TAT) encoded by the At5g53970 gene was studied using two independent knock-out mutants. Gas chromatography-mass spectrometry based metabolic profiling revealed a specific increase in tyrosine levels, supporting the proposed function of At5g53970 as a tyrosine-specific aminotransferase not involved in tyrosine biosynthesis, but rather in utilization of tyrosine for other metabolic pathways. The TAT activity of the At5g53970-encoded protein was verified by complementation of the Escherichia coli tyrosine auxotrophic mutant DL39, and in vitro activity of recombinantly expressed and purified At5g53970 was found to be specific for tyrosine. To investigate the physiological role of At5g53970, the consequences of reduction in tyrosine utilization on metabolic pathways having tyrosine as a substrate were analysed. We found that tocopherols were substantially reduced in the mutants and we conclude that At5g53970 encodes a TAT important for the synthesis of tocopherols in Arabidopsis.

Enhancing the optical excitation efficiency of a single self-assembled quantum dot with a plasmonic nanoantenna.

We demonstrate how the controlled positioning of a plasmonic nanoparticle modifies the photoluminescence of a single epitaxial GaAs quantum dot. The antenna particle leads to an increase of the luminescence intensity by about a factor of 8. Spectrally and temporally resolved photoluminescence measurements prove an increase of the quantum dot's excitation rate.

Electrospun Hybrid Perovskite Fibers-Flexible Networks of One-Dimensional Semiconductors for Light-Harvesting Applications.

Thin-film organic-inorganic hybrid perovskite (MeNH3PbI3) solar cells have displayed remarkably high photoconversion efficiencies, making their net-shaping as flexible device elements desirable for a number of applications. Simulations show greatly enhanced light absorption in perovskite fibers in comparison to their thin-film counterparts, which demand the processing of hybrid perovskites in the one-dimensional morphology. We report here on the single-step fabrication of MeNH3PbI3 nanofibers on a customized electrospinning process performed under inert conditions. Our results demonstrate reproducible synthesis of electrospun fiber mats in which the fiber dimensions were tailored by adjusting the polymer (PVP) content. Photoluminescence studies on the perovskite fibers revealed a blue shift of the emission peak possibly due to strain or charge confinement effects. The hybrid perovskite nanofibers offer promising applications in flexible and stretchable optoelectronics.

Coupling a single solid-state quantum emitter to an array of resonant plasmonic antennas.

Plasmon resonant arrays or meta-surfaces shape both the incoming optical field and the local density of states for emission processes. They provide large regions of enhanced emission from emitters and greater design flexibility than single nanoantennas. This makes them of great interest for engineering optical absorption and emission. Here we study the coupling of a single quantum emitter, a self-assembled semiconductor quantum dot, to a plasmonic meta-surface. We investigate the influence of the spectral properties of the nanoantennas and the position of the emitter in the unit cell of the structure. We observe a resonant enhancement due to emitter-array coupling in the far-field regime and find a clear difference from the interaction of an emitter with a single antenna.

Acute Wallerian degeneration of middle cerebellar peduncles due to basilar artery thrombosis.

Wallerian degeneration (WD) is the process of demyelination and disintegration of the distal axonal segment following the interruption of the axonal integrity or damage to the neuron. We report a patient having WD of middle cerebellar peduncles due to pontine infarction caused by basilar artery thrombosis. We review the anatomy and discuss the pathogenesis of this condition.