Das Spektrum odontogener Zysten – ein Update

Odontogene Zysten sind Läsionen, die im Patientengut der Mund‑, Kiefer- und Gesichtschirurgie oft zu finden sind. Sie sind um etwa 20-mal häufiger als echte odontogene Tumoren. Allen voran rangiert die entzündlich bedingte radikuläre Zyste, gefolgt von der entwicklungsbedingten follikulären Zyste. Gemeinsam ist allen odontogenen Zysten wie auch Tumoren, dass sie sich radiologisch als Osteolysen manifestieren und sichere radiologische Unterscheidungsmerkmale zwischen den einzelnen Entitäten oftmals fehlen. Klarheit bringt in vielen Fällen erst die histopathologische Untersuchung. Allerdings ist zu beachten, dass eine akkurate Entitätsdiagnose nur in einer engen interdisziplinären Zusammenarbeit möglich ist. Aus histopathologischer Sicht kann der Pathologe/die Pathologin nur eine dezidierte Diagnose stellen, wenn auch ihm/ihr das klinische Bild (Vitalitätsstatus des assoziierten Zahns, Zufallsbefund oder symptomatisch, Lockerung der Zähne etc.) sowie das radiologische Erscheinungsbild (Lokalisation der Osteolyse, Präsenz retinierter Zähne, parallel vorhandene radiologische Auffälligkeiten etc.) bekannt sind. Die Begutachtung des radiologischen Bildes erfordert dabei in aller Regel die Einsicht des gesamten Datensatzes eines digitalen Volumentomogramms oder eines Orthopantomogramms in guter Auflösung, da unvollständige Ausschnitte oder Beschreibungen Fehlinterpretationen begünstigen können. Die zunehmende Digitalisierung ist hier von großem Vorteil und ein Datenträger mit allen relevanten (insbesondere präinterventionellen) Bildern wird von erfahrenen Oralpathologen immer gern entgegengenommen. In jedem Falle sollte bei Diskrepanzen zwischen histopathologischer Diagnose und klinisch-radiologischem Bild bzw. schwierigen oder ungewöhnlichen Fällen eine interdisziplinäre Diskussion angestrebt werden. = Odontogenic cysts are frequently found in oral and maxillofacial surgery patients. They are about 20 times more common than true odontogenic tumors. The inflammatory radicular cyst is the most common, followed by the developmental dentigerous cyst. Common to all odontogenic cystsand cystic tumors is the lytic appearance in imaging analyses and the lack of reliable radiological features to distinguish the individual entities. In many cases, only a biopsy can provide clarity. However, it should be noted that an accurate diagnosis is only possible in the context of close interdisciplinary cooperation. From a histopathological point of view, the pathologist can only make a definite diagnosis if they are also familiar with the clinical picture (vitality status of the associated tooth, incidental or symptomatic findings, loosening of the teeth, etc.) and the radiological appearance (site, presence of retained teeth, parallel radiological abnormalities, etc.). Evaluation of the radiological image usually requires the entire data set of a cone-beam CT or an orthopantomogram in sufficient resolution, since incomplete data or descriptions can facilitate misinterpretations. The progress made in digitalization is thereby of great advantage and the (pre-interventional) images will always be welcomed by experienced oral pathologists. In case of discrepancies between the histopathological diagnosis and the clinical-radiological image, and in difficult or unusual cases, an interdisciplinary discussion is strongly recommended

Luminescence tuning of MOFs via ligand to metal and metal to metal energy transfer by co-doping of 2∞[Gd2Cl6(bipy)3]*2bipy with europium and terbium

The series of anhydrous lanthanide chlorides LnCl3, Ln=Pr–Tb, and 4,4'-bipyridine (bipy) constitute isotypic MOFs of the formula 2∞[Ln2Cl6(bipy)3]*2bipy. The europium and terbium containing compounds both exhibit luminescence of the referring trivalent lanthanide ions, giving a red luminescence for Eu3+ and a green luminescence for Tb3+ triggered by an efficient antenna effect of the 4,4'-bipyridine linkers. Mixing of different lanthanides in one MOF structure was undertaken to investigate the potential of this MOF system for colour tuning of the luminescence. Based on the gadolinium containing compound, co-doping with different amounts of europium and terbium proves successful and yields solid solutions of the formula 2∞[Gd2-x-yEuxTbyCl6(bipy)3]*2bipy (1–8), 0≤x, y≤0.5. The series of MOFs exhibits the opportunity of tuning the emission colour in-between green and red. Depending on the atomic ratio Gd:Eu:Tb, the yellow region was covered for the first time for an oxygen/carboxylate-free MOF system. In addition to a ligand to metal energy transfer (LMET) from the lowest ligand-centered triplet state of 4,4'-bipyridine, a metal to metal energy transfer (MMET) between 4f-levels from Tb3+ to Eu3+ is as well vital for the emission colour. However, no involvement of Gd3+ in energy transfers is observed rendering it a suitable host lattice ion and connectivity centre for diluting the other two rare earth ions in the solid state. The materials retain their luminescence during activation of the MOFs for microporosity

A spatial light modulator using BSO crystals

The combined use of the photoelectric and electro-optic properties of the Bi12SiO20 (BSO)-crystal leads to a new possibility of realizing a spatial light modulator. Under certain geometrical conditions, which will be discussed, it is possible to realize, that the BSO-crystal becomes birefringent depending on the local illuminance; the physical connection between the distributions of birefringence and illuminance will be shown. The BSO-crystal combined with a polarizer setup works as a spatial light modulator or as an incoherent to coherent converter

New light valve based in photoinduced space charge fields in BSO-crystals

The combined photoelectric and electrooptic properties of the BSO-crystal lead to a new possibility of realizing a real time spatial light modulator. Under certain geometrical conditions the crystal becomes birefringent in dependence on the local illuminance. Together with a suitable polarizer setup the crystal works as well as an incoherent to coherent converter as for contrast inversion

Chaos in Axially Symmetric Potentials with Octupole Deformation

Classical and quantum mechanical results are reported for the single particle motion in a harmonic oscillator potential which is characterized by a quadrupole deformation and an additional octupole deformation. The chaotic character of the motion is srongly dependent on the quadrupole deformation in that for a prolate deformation virtually no chaos is discernible while for the oblate case the motion shows strong chaos when the octupole term is turned on.Comment: 6 pages LaTex plus 4 figures available by contacting the authors directly, published in PHYS.REV.LETT. 72(1994) 235

PLOS One / Comparison of EEG-Features and classification methods for motor imagery in patients with disorders of consciousness

Current research aims at identifying voluntary brain activation in patients who are behaviorally diagnosed as being unconscious, but are able to perform commands by modulating their brain activity patterns. This involves machine learning techniques and feature extraction methods such as applied in brain computer interfaces. In this study, we try to answer the question if features/classification methods which show advantages in healthy participants are also accurate when applied to data of patients with disorders of consciousness. A sample of healthy participants (N = 22), patients in a minimally conscious state (MCS; N = 5), and with unresponsive wakefulness syndrome (UWS; N = 9) was examined with a motor imagery task which involved imagery of moving both hands and an instruction to hold both hands firm. We extracted a set of 20 features from the electroencephalogram and used linear discriminant analysis, k-nearest neighbor classification, and support vector machines (SVM) as classification methods. In healthy participants, the best classification accuracies were seen with coherences (mean = .79; range = .53.94) and power spectra (mean = .69; range = .40.85). The coherence patterns in healthy participants did not match the expectation of central modulated -rhythm. Instead, coherence involved mainly frontal regions. In healthy participants, the best classification tool was SVM. Five patients had at least one feature-classifier outcome with p0.05 (none of which were coherence or power spectra), though none remained significant after false-discovery rate correction for multiple comparisons. The present work suggests the use of coherences in patients with disorders of consciousness because they show high reliability among healthy subjects and patient groups. However, feature extraction and classification is a challenging task in unresponsive patients because there is no ground truth to validate the results

Grundlagenuntersuchung, Entwicklung und Erprobung optischer Sensoren für die Qualitätssicherung und zum Einsatz an Montagerobotern in der flexiblen Montage : Teilprojekt A4

Die dreidimensionale berührungslose Objektvermessung ist eine zentrale Sensoraufgabe in der industriellen Montage und Qualitätssicherung. Hierfür geeignet sind optische Triangulationsverfahren, die sich im Vergleich zu anderen Verfahren durch hohe relative Distanz- und Lateralauflösung sowie geringen apparativen Aufwand auszeichnen