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This study aimed to compare the view into the maxillary sinus using the posterior translacrimal approach compared with grade 3 antrostomy.
Grade 3 antrostomy followed by a posterior translacrimal approach was performed on four cadavers. The maximum intramaxillary view was documented endoscopically guided by electromagnetic navigation. Representative screenshots were evaluated in a blinded manner by three independent sinus surgeons. In addition, a prospective investigation of specific complications in the post-operative course of consecutive patients was performed.
In the cadaver study, the posterior translacrimal approach provided a significantly better view into the maxillary sinus compared with grade 3 antrostomy. In the clinical study, only 1 out of 20 patients reported on a minor problem with lacrimal drainage at 6 months.
The posterior translacrimal approach to visualising the maxillary sinus should be considered a strong alternative to more radical techniques.
Hybrid magnetic/plasmonic nanoparticles possess properties originating from each individual material. Such properties are beneficial for biological applications including bio-imaging, targeted drug delivery, in vivo diagnosis and therapy. Limitations regarding their stability and toxicity, however, challenge their safe use. Here, the one-step flame synthesis of composite SiO2-coated Ag/Fe2O3 nanoparticles is demonstrated. The hermetic SiO2 coating does not influence the morphology, the superparamagnetic properties of the iron oxide particles and the plasmonic optical properties of the silver particles. Therefore, the hybrid SiO2-coated Ag/Fe2O3 nanoparticles exhibit desired properties for their employment in bio-applications.
Most of the flare stars (FSs) discovered in that field are very faint and are missing from all previously published lists of Pleiades cluster members. Reliable membership probabilities (MPs) were only determined for one third of these objects while the rest were supposed to be more or less probable members with a few exceptions. A recent proper motion survey of that field (Schilbach et al. 1995) based on plates taken with the Tautenburg Schmidt telescope and extended to an area of 16.5 square degrees provided new cluster MPs and also photometric data even for a number of the lowest luminosity stars (in fact the faintest object measured has V = 18.26). Of the 520 known FSs in the field 437 (85%) were successfully identified, their J2000.0 coordinates, high precision proper motion components and apparent photographic R magnitudes (and for the majority of them their V and B magnitudes too) determined. Based on these data new cluster MPs have been deduced which show that a considerable number (40%) of the so called Pleiades FSs are not members of that cluster at all. This conclusion follows the tendency already found: when we involve more and more faint FSs into the investigations the percentage of non-members monotonically increases (cf. Haro et al. 1982 and references therein).
Dispersed interferometer fringes as a new type of signal are currently under discussion for several space interferometry mission projects (GAIA, FAME, DIVA). The dispersed fringes are directly recorded by CCD mosaics whichare operated in drift-scan mode on board a continuously rotating satellite. They allow combined astrometric (perpendicular to the fringes, i.e. in the direction of the drift scan) and spectro-photometric measurements (in the direction of the dispersion of the fringes, i.e. perpendicular to the drift scan). We have simulated polychromatic dispersed fringe patterns of stars with known spectra. The specific instrument parameters used for the simulation are those envisaged for the DIVA instrument, with realistic assumptions on various noise contributions. The results can be scaled to GAIA and FAME instrument parameters. We have investigated simple algorithms which can be implemented in an on-board data reduction and used for the real-time attitude determination with bright and single stars. On the preliminary basis of 100 simulations per star of a given magnitude and spectral type, we have obtained first estimates of the achievable accuracy of the astrometric measurements and of the location of the photometric zero point λo.
From measurements of Tautenburg Schmidt plates with the APM facility in Cambridge we obtained absolute proper motions of the Galactic globular clusters M 3 and M 92 directly with respect to large numbers of background galaxies (Scholz et al. 1993, 1994). We have extended our work to the dSphs in Draco and Ursa Minor (Scholz & Irwin 1994) and to other Galactic globular clusters using Tautenburg, Palomar and UK Schmidt plates. Combining our absolute proper motion of a cluster with its known radial velocity and distance (using common parameters of the solar motion) we derive the cluster orbit in the Galaxy (cf. Odenkirchen & Brosche 1992).
The combination of Tautenburg plates and automatic measuring machines provides a powerful tool to obtain photometry and proper motions of a great number of stars for statistical investigations of our Galaxy. Photographic photometry with an accuracy of about 0.07 mag can be obtained provided two plates of the same colour and a sufficient number of photometric standards are available. With two plate pairs and a 20 years baseline, a proper motion accuracy better than 4 mas/year can be achieved for stars over a wide range of magnitudes. Outside the Galactic plane proper motions are determined with respect to hundreds of background galaxies.
Low-pressure plasma deposition (LPPD) was used to synthesize an in-situ MoSi2/SiC composite using 100% methane (CH4) as a powder carrier gas. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) identified MoSi2, Mo5Si3, Mo5Si3C, Si02, and SiC as the phases present in the composite. XRD and XPS revealed ∼6 vol% SiC in the as-sprayed material. Annealing of the as-sprayed composite increased the SiC content to ∼8 vol% while reducing the Si02 volume fraction. Transmission electron microscopy studies revealed a fine homogeneous distribution of SiC and/or carbide particles at prior splat boundaries in the MoSi2 matrix. Wavelength dispersive spectroscopy (WDS) confirmed the increased presence of carbon in the in-situ materials. Fracture toughness measurements yielded values on the order of 10 MPa m½ for annealed composites. The creep behavior of the LPPD reactive spray composite dramatically improved compared to unreinforced LPPD MoSi2. Additionally, the creep behavior was shown to be equal to or better than that of powder metallurgy MoSi2/SiC composites containing higher percentages of SiC.
For a detailed investigation of the kinematics of our Galaxy we need accurate proper motions and photometric data of stars over a wide range of magnitudes. The proper motions have to be obtained with respect to an extragalactic, i.e. nonrotating reference system. The best way to determine absolute proper motions of a great number of stars for further statistical analysis is to use the enormous amount of information stored on photographic plates taken with large Schmidt telescopes within the last decades. Since automated measuring machines have become available it is no longer a problem to extract this information from a Schmidt plate. Large Schmidt plates cover a sky area of more than 30 square degrees with usually thousands of stars and hundreds of galaxies per square degree outside the galactic plane. With the Tautenburg Schmidt telescope (134/200/400) more than 8000 plates have been taken in selected Northern sky areas since it was mounted in 1960. A 24 cm × 24 cm Tautenburg plate covers a field of about 10 square degrees, and a 20 minute exposure of a B plate has a limiting magnitude of 19 to 21. In comparison to other large Schmidt telescopes the plate bending is reduced to a minimum due to the four metre focal length and the use of relatively small plates. Therefore irregular positional shifts of the emulsion caused by the rebending after the exposure are of less influence. The large focal length leads to a plate scale of 51 arcsec/mm providing a relatively high positional accuracy.
A programme for the determination of proper motions and photographic B, V, R magnitudes for stars up to 18m within a 4° by 4° region centered near Alcyone is described. We use MAMA measurements of plates taken with Tautenburg and OCA Schmidt telescopes as well as with the double refractor of Bonn and Carte du Ciel plates. To check the stability of the solution three different methods of reduction are applied.
According to the results of the pilot programme a final proper motion accuracy of about 2 mas/a can be achieved for the majority of stars in the survey.
A proposed new genus of scalpellomorph cirriped, Tetrinis n. gen., based on T. serenuportus n. sp., is known from three Kansas localities in the middle part of the Fairport Member of the Carlile Shale where it is epizoic on the bivalve Inoceramus cuvieri. The stalked cirriped Stramentum elegans coexisted with T. serenuportus and the bryozoan Proboscina sp. was epizoic on S. elegans but not on T. serenuportus. The genus is readily distinguished from all other scalpellomorph cirripeds in the character of the capitulum, which comprises 28 slightly overlapping plates arranged in four whorls. Tetrinis serenuportus displays a large rostrum and an upper latus that is situated low in the capitulum between the scutum and tergum, allowing the two latter plates to touch. All umbos are apical except for that of the scutum, which is subapical and closer to the apex than to the base. The new form apparently has a narrow stratigraphic range and has potential as a biostratigraphic marker.
Besides the link of the HIPPARCOS reference frame to extragalactic objects via radio stars or by the HST, also photographic astrometry is able to calibrate the HIPPARCOS proper motions with regard to an inertial system. Numerical simulations have shown that even with a very small number of well-distributed link fields (3 to 5) the photographic method is competitive with other techniques.
Stratigraphic distribution of two key brachiopod species in the Ramp Creek Formation and Harrodsburg Limestone (middle Mississippian) in south-central Indiana suggests the boundary between the Osagean and Meramecian Series lies in the lower part of the Ramp Creek Formation. Marginirugus magnus (Meek and Worthen), an Osagean index fossil, ranges into the lower part of the Ramp Creek Formation. Warsawia lateralis (Hall), a Meramecian index fossil, also occurs in the lower part of the Ramp Creek Formation and in the lower part of the Harrodsburg Limestone. Thus, the upper part of the Edwardsville Formation and lower part of the Ramp Creek Formation in Indiana are temporally equivalent to the lower half of the Warsaw Formation in the Mississippi Valley. The upper part of the Ramp Creek Formation and the lower part of the Harrodsburg Limestone are temporally equivalent to the upper half of the Warsaw Formation.
The measurements of AGK3 stars carried out with the automated measuring machine MAMA in Paris were used for the estimation of the accuracy of stellar positions on Tautenburg and CERGA plates. The results show good coincidence of stellar positions derived with both Schmidt telescopes. The achieved accuracy is high enough to use combined observations for improving present positions in the catalog AGK3.
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