129 research outputs found
Myalgie der Kiefermuskulatur
Zusammenfassung: Kiefermuskelschmerzen können als regionale Manifestation muskuloskelettaler Beschwerden betrachtet werden, wie sie in Ă€hnlicher Form auch in anderen Körperregionen zu beobachten sind. Zusammen mit den Kiefergelenkschmerzen und nicht schmerzhaften Störungen der Unterkieferbeweglichkeit werden sie unter dem Begriff "kraniomandibulĂ€re Dysfunktion" (CMD) zusammengefasst. Eine Reihe von biophysikalischen Risikofaktoren ist mit diesem Beschwerdebild assoziiert. Valide Diagnoseinstrumente ermöglichen die therapeutisch relevante Differenzierung der verschiedenen CMD-Subgruppen. Der weitaus ĂŒberwiegende Teil der Kiefermuskelschmerzen ist gut behandelbar. Bei einem nicht unerheblichen Anteil der Patienten persistieren die Muskelschmerzen jedoch trotz therapeutischer MaĂnahmen. Die Kenntnis der zugrunde liegenden neurobiologischen HintergrĂŒnde akuter und chronischer Schmerzen hilft bei der Wahl angemessener Therapien und bei der AbschĂ€tzung des Therapieerfolg
Variability and Lower Bound of Fracture Toughness of Welds in the Ductile to Brittle Transition Regime
AbstractThe reference temperature T0 was measured for both T-S and T-L- specimen orientation in 24 layers across the thickness of the beltline weld of a reactor pressure vessel. It turned out to vary in a bandwidth of more than 40K. Because of a high scatter, no clear pattern of T0 as a function of the thickness position could be recognized. A more detailed analysis revealed that the median of KJc was considerably steeper than predicted by the Master-Curve, which leads to a bias of T0 with respect to the test- temperature relative to T0. By a modified evaluation procedure, the scatter of the reference temperature could be significantly reduced, which enabled the global pattern of T0 to be recognized. By comparing the theoretical lower bound to KJc-data of the used specimens with the individual measured KJc a representative T0 that characterizes the overall toughness behaviour of the weld was determined. It turned out to be about 10K lower than the maximum local T0
Vorschlag einer Klassifikation der Odontalgien
Zusammenfassung: Hintergrund: Die PrĂ€valenz von Zahnschmerzen in der Bevölkerung ist beachtlich. Bislang publizierte Klassifikationen der Odontalgien erscheinen jedoch fĂŒr klinische Belange nicht ausreichend strukturiert. Zudem finden nicht alle bekannten Zahnschmerzformen BerĂŒcksichtigung. Ziel dieser Abhandlung ist die Vorstellung einer verfeinerten und aktuellem Wissen genĂŒgenden Einteilung der Odontalgien und die Zusammenfassung ihrer jeweiligen Merkmale zum Zweck einer raschen Diagnosestellung. Ergebnisse: Die erarbeitete Klassifikation unterscheidet 7Schmerzformen: 1."Dentin-Schmerz" (ausgehend vom Pulpagewebe), 2."Pulpa-Schmerz" (ausgehend vom Pulpagewebe), 3.parodontaler Schmerz, 4.alveolĂ€r-ossĂ€rer Schmerz, 5.atypische Odontalgie, 6.in die ZĂ€hne ĂŒbertragener (heterotoper) Schmerz, 7.Zahnschmerz in Zusammenhang mit primĂ€r psychosozialen Faktoren. Schlussfolgerungen: Die vorgeschlagene Klassifikation erscheint geeignet, die verschiedenen Formen der Odontalgien differenzierter darzustellen, als dies mit den bisherigen Einteilungen der Fall war. Ihre Brauchbarkeit bzw. Ăberlegenheit gegenĂŒber anderen Klassifikationen wird sich im klinischen Alltag erweisen mĂŒsse
Therapie bei Schmerzen der Kaumuskulatur: Aktualisierung der Empfehlungen
Zusammenfassung: Kaumuskelschmerzen sind nach Zahnschmerzen die hĂ€ufigsten Schmerzen in der Kiefer-Gesichts-Region. Nach einer Zusammenfassung der vom InterdisziplinĂ€ren Arbeitskreis fĂŒr Mund- und Gesichtsschmerzen der Deutschen Schmerzgesellschaft im Jahre 2007 veröffentlichten Therapieempfehlungen wird anhand einer Literaturrecherche der Kenntnisstand von Ătiologie, Diagnostik und therapeutischen Möglichkeiten aktualisiert. Es erfolgte eine systematische Literatursuche in PubMed, der Cochrane Library und der Verlagsdatenbank der Deutschen ZahnĂ€rztlichen Zeitschrift. Die Ergebnisse bestĂ€tigen unsere frĂŒheren Empfehlungen, dass bei der ĂŒberwiegenden Zahl der Patienten mit nichtinvasiven, reversiblen MaĂnahmen Schmerzlinderung bzw. Schmerzfreiheit erreicht werden kann. Kurz- und Langzeitstudien haben weitere Belege dafĂŒr geliefert, dass verschiedene Behandlungsverfahren vergleichbar wirksam sind. Bei chronischen VerlĂ€ufen ist neben der biomedizinischen Standardtherapie eine schmerzpsychologische Betreuung obligat. Als empfehlenswert wurden AufklĂ€rung, Okklusionsschienen, physiotherapeutische Selbstbehandlung und Akupunktur, als eingeschrĂ€nkt empfehlenswert physikalische Therapie, Pharmakotherapie und psychologische Schmerztherapie beurteil
Seizure characterisation using frequency-dependent multivariate dynamics
The characterisation of epileptic seizures assists in the design of targeted pharmaceutical seizure prevention techniques
and pre-surgical evaluations. In this paper, we expand on recent use of multivariate techniques to study the crosscorrelation
dynamics between electroencephalographic (EEG) channels. The Maximum Overlap Discrete Wavelet
Transform (MODWT) is applied in order to separate the EEG channels into their underlying frequencies. The
dynamics of the cross-correlation matrix between channels, at each frequency, are then analysed in terms of the
eigenspectrum. By examination of the eigenspectrum, we show that it is possible to identify frequency dependent
changes in the correlation structure between channels which may be indicative of seizure activity.
The technique is applied to EEG epileptiform data and the results indicate that the correlation dynamics vary over
time and frequency, with larger correlations between channels at high frequencies. Additionally, a redistribution of wavelet energy is found, with increased fractional energy demonstrating the relative importance of high frequencies
during seizures. Dynamical changes also occur in both correlation and energy at lower frequencies during seizures,
suggesting that monitoring frequency dependent correlation structure can characterise changes in EEG signals during
these. Future work will involve the study of other large eigenvalues and inter-frequency correlations to determine
additional seizure characteristics
Cross-correlation dynamics in financial time series
The dynamics of the equal-time cross-correlation matrix of multivariate financial time series is explored by examination of the eigenvalue spectrum over sliding time windows. Empirical results for the S&P 500 and the Dow Jones Euro Stoxx 50 indices reveal that the dynamics of
the small eigenvalues of the cross-correlation matrix, over these time windows, oppose those of the largest eigenvalue. This behaviour is shown to be independent of the size of the time window and the number of stocks examined. A basic one-factor model is proposed, which captures the main dynamical features of the eigenvalue spectrum of the empirical data. Through the addition of perturbations to the one-factor model, (leading to a market plus sectors model), additional sectoral features are added, resulting in an Inverse Participation Ratio comparable to that found
for empirical data
Adenylate effects on protein phosphorylation in the interenvelope lumen of pea chloroplasts
A 64-kilodalton (kDa) protein, situated in the lumen between the inner and outer envelopes of pea (Pisum sativum L.) chloroplasts (Soll and Bennett 1988, Eur. J. Biochem., 175, 301â307) is shown to undergo reversible phosphorylation in isolated mixed envelope vesicles. It is the most conspicuously labelled protein after incubation of envelopes with 33 nmol·1-1 [-32P]ATP whereas incubation with 50 mol·1-1 [-32P]ATP labels most prominently two outer envelope proteins (86 and 23 kDa). Half-maximum velocity for phosphorylation of the 64-kDa protein occurs with 200 nmol·1-1 ATP, and around 40 mol·1-1 ATP for phosphorylation of the 86- and 23-kDa proteins, indicating the operation of two distinct kinases. GGuanosine-, uridine-, cytidine 5-triphosphate and AMP are poor inhibitors of the labelling of the 64-kDa protein with [-32P]ATP. On the other hand, ADP has a potent influence on the extent of labelling (half-maximal inhibition at 1â5 mol·1-1). The ADP-dependent appearance of 32P in ATP indicates that ADP acts by reversal of kinase activity and not as a competitive inhibitor. However, the most rapid loss of 32P from pre-labelled 64-kDa protein occurs when envelope vesicles are incubated with ATP t1/2=15 s at 20 molsd1-1 ATP). This induced turnover of phosphate appears to be responsible for the rapid phosphoryl turnover seen in situ
Sr2V3O9 and Ba2V3O9: quasi one-dimensional spin-systems with an anomalous low temperature susceptibility
The magnetic behaviour of the low-dimensional Vanadium-oxides Sr2V3O9 and
Ba2V3O9 was investigated by means of magnetic susceptibility and specific heat
measurements. In both compounds, the results can be very well described by an
S=1/2 Heisenberg antiferromagnetic chain with an intrachain exchange of J = 82
K and J = 94 K in Sr2V3O9 and Ba2V3O9, respectively. In Sr2V3O9,
antiferromagnetic ordering at T_N = 5.3 K indicate a weak interchain exchange
of the order of J_perp ~ 2 K. In contrast, no evidence for magnetic order was
found in Ba2V3O9 down to 0.5 K, pointing to an even smaller interchain
coupling. In both compounds, we observe a pronounced Curie-like increase of the
susceptibility below 30 K, which we tentatively attribute to a staggered field
effect induced by the applied magnetic field. Results of LDA calculations
support the quasi one-dimensional character and indicate that in Sr2V3O9, the
magnetic chain is perpendicular to the structural one with the magnetic
exchange being transferred through VO4 tetrahedra.Comment: Submitted to Phy. Rev.
Nucleon axial and pseudoscalar form factors from the covariant Faddeev equation
We compute the axial and pseudoscalar form factors of the nucleon in the
Dyson-Schwinger approach. To this end, we solve a covariant three-body Faddeev
equation for the nucleon wave function and determine the matrix elements of the
axialvector and pseudoscalar isotriplet currents. Our only input is a
well-established and phenomenologically successful ansatz for the
nonperturbative quark-gluon interaction. As a consequence of the axial
Ward-Takahashi identity that is respected at the quark level, the
Goldberger-Treiman relation is reproduced for all current-quark masses. We
discuss the timelike pole structure of the quark-antiquark vertices that enters
the nucleon matrix elements and determines the momentum dependence of the form
factors. Our result for the axial charge underestimates the experimental value
by 20-25% which might be a signal of missing pion-cloud contributions. The
axial and pseudoscalar form factors agree with phenomenological and lattice
data in the momentum range above Q^2 ~ 1...2 GeV^2.Comment: 17 pages, 7 figures, 1 tabl
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