204 research outputs found
Neural Correlates of Parkinsonian Syndromes
The thesis investigated objective neuroimaging biomarkers in parkinsonian syndromes, which could be applied to increase diagnostic accuracy. To find convergence of the literature concerning disease-specific patterns in Parkinson’s disease and progressive supranuclear palsy, we conducted meta-analyses. In Parkinson’s disease glucose hypometabolism was re- vealed in bilateral inferior parietal cortex and left caudate nucleus and focal gray matter atrophy in the middle occipital gyrus. In progressive supranu- clear palsy we identified gray matter atrophy in the midbrain and white mat- ter atrophy in the cerebral/cerebellar pedunculi and midbrain. In sum, in Parkinson’s disease hypometabolism outperforms atrophy and in progres- sive supranuclear palsy we validated pathognomonic markers as disease- specific. Our studies create a novel framework to investigate disease- specific regional alterations for use in clinical routine. Further, we inves- tigated neural correlates by voxel-based morphometry and discriminated disease and clinical syndrome by multivariate pattern recognition in sin- gle patients with corticobasal syndrome and corticobasal syndrome with a unique syndrome - alien/ anarchic limb phenomenon. We found gray matter volume differences between patients and controls in asymmetric frontotem- poral/ occipital regions, motor areas, and insulae. The frontoparietal gyrus including the supplementary motor area contralateral to the side of the af- fected limb was specific for alien/ anarchic limb phenomenon. The predic- tion of the disease among controls was 79.0% accurate. The prediction of the specific syndrome within a disease reached an accuracy of 81.3%. In conclusion, we reliably classified patients and controls by objective pattern recognition. Moreover, we were able to predict a specific clinical syndrome within a disease, paving the way to individualized disease prediction.:SELBSTSTÄNDIGKEITSERKLÄRUNG I
ACKNOWLEDGMENTS II
SUMMARY III
ZUSAMMENFASSUNG VIII
BIBLIOGRAPHISCHE DARSTELLUNG XIV
CONTENTS XVI
1 GENERAL INTRODUCTION 1
1.1 ParkinsonianSyndromes .................... 2
1.2 Parkinson’sDisease ....................... 2
1.2.1 DiagnosticCriteria .................... 3
1.3 ProgressiveSupranuclearPalsy ................ 4
1.3.1 DiagnosticCriteria .................... 5
1.4 CorticobasalDegeneration ................... 5
1.4.1 DiagnosticCriteria .................... 7
1.5 ImagingBiomarkers ....................... 7
1.6 CurrentThesis .......................... 9 1.6.1
MotivationandFramework ............... 9 1.6.2
ResearchQuestions................... 9
2 GENERAL MATERIALS AND METHODS 12
2.1 MagneticResonanceImaging.................. 12
2.2 AnalyticalMethods........................ 13
2.2.1 Meta-Analysis ...................... 13
2.2.2 Voxel-BasedMorphometry ............... 14
2.2.3 Support-Vector Machine Classification . . . . . . . . . 15
2.3 Multi-CentricData ........................ 16
2.4 ClinicalAssessment ....................... 17
3 Study 1
4 Study 2
5 Study 3
6 Study 4
7 Study 5
8 DISCUSSION 73
8.1 MainFindings........................... 73
8.2 Statistical Approaches to Find Imaging Biomarker . . . . . . 76
8.3 Brain Alterations and their Utility as Imaging Biomarker . . . . 77
8.4 Limitations ............................ 78
8.5 Contributions of the Current Thesis and Future Directions . . 79
9 REFERENCES
APPENDIX XVIII
LIST OF AUTHORSHIP XXVII
CURRICULUM VITÆ XXXVII
It’s not a science isolated in a bubble : Grave Encounters in Forensic Anthropology in Colombia and Peru
My doctoral research explores the experience of forensic anthropologists in places of sociopolitical unrest, specifically focusing on Colombia and Peru. Forensic anthropologists, who specialise in identifying skeletal remains, analysing skeletal trauma, and providing expert opinions on the circumstances of death, often serve as expert witnesses in legal proceedings. However, in Latin America, the concept of witnessing extends beyond the courtroom, encompassing a broader spectrum of knowledge generation. This dissertation examines the diverse encounters faced by forensic anthropologists in Colombia and Peru, including encounters with human remains and the legacies of political violence, encounters with the families of the missing, perpetrators, and a precarious institutional landscape. I argue that these encounters shape the moral experience of forensic anthropologists – making them not only unwanted witnesses but moral witnesses – and exposing them to specific risks, dangers, stressors, and emotional impacts. The research presented here suggests that the entire context of forensic anthropological work can potentially shape forensic anthropologists in profound ways. The findings indicate that the impact on forensic anthropologists extends beyond the immediate tasks they perform, such as interacting with bereaved families or encountering perpetrators of violence. The broader sociopolitical landscape, characterised by pervasive violence and precarity, also plays a significant role in shaping these professionals.My findings suggest that the knowledge forensic anthropologists produce, the things they witness, and the sociopolitical context they operate in all contribute to shaping their personal lives and decisions. The research further posits that the conditions under which forensic anthropologists work create an environment conducive to moral injury – an injury to one’s moral conscience which stems from witnessing or participating in events that go against one’s moral beliefs. These same conditions and contexts provide the discursive and practical resources that forensic anthropologists utilise to manage their experiences, cope with their work’s psychological and emotional impacts and navigate the multifaceted challenges inherent in their profession
CCI-779 (Temsirolimus) exhibits increased anti-tumor activity in low EGFR expressing HNSCC cell lines and is effective in cells with acquired resistance to cisplatin or cetuximab
Background: The mammalian target of rapamycin (mTOR) signaling pathway plays a pivotal role in numerous cellular processes involving growth, proliferation and survival. The purpose of this study was to investigate the anti-tumoral effect of the mTOR inhibitor (mTORi) CCI-779 in HNSCC cell lines and its potency in cisplatin- and cetuximab-resistant cells. Methods: A panel of 10 HNSCC cell lines with differences in TP53 mutational status and basal cisplatin sensitivity and two isogenic models of acquired resistance to cisplatin and cetuximab, respectively were studied. Cell survival after treatment with CCI-779, cisplatin and cetuximab alone or in combination was determined by MTT assays. Potential predictive biomarkers for tumor cell sensitivity to CCI-779 were evaluated. Results: We observed considerable heterogeneity in sensitivity of HNSCC cell lines to CCI-779 monotherapy. Sensitivity was observed in TP53 mutated as well as wild-type cell lines. Total and p-EGFR expression levels but not the basal activity of the mTOR and MAPK signaling pathways were correlated with sensitivity to CCI-779. Resistant cells with increased EGFR activation could be sensitized by the combination of CCI-779 with cetuximab. Interestingly, cell lines with acquired resistance to cisplatin displayed a higher sensitivity to CCI-779 whereas cetuximab-resistant cells were less sensitive to the drug, but could be sensitized to CCI-779 by EGFR blockade. Conclusions: Activity of CCI-779 in HNSCC cells harboring TP53 mutations and displaying a phenotype of cisplatin resistance suggests its clinical potential even in patients with dismal outcome after current standard treatment. Cetuximab/mTORi combinations might be useful for treatment of tumors with high expression of EGFR/p-EGFR and/or acquired cetuximab resistance. This combinatorial treatment modality needs further evaluation in future translational and clinical studies
The Basso-Dixon Formula and Calabi-Yau Geometry
We analyse the family of Calabi-Yau varieties attached to four-point fishnet
integrals in two dimensions. We find that the Picard-Fuchs operators for
fishnet integrals are exterior powers of the Picard-Fuchs operators for ladder
integrals. This implies that the periods of the Calabi-Yau varieties for
fishnet integrals can be written as determinants of periods for ladder
integrals. The representation theory of the geometric monodromy group plays an
important role in this context. We then show how the determinant form of the
periods immediately leads to the well-known Basso-Dixon formula for four-point
fishnet integrals in two dimensions. Notably, the relation to Calabi-Yau
geometry implies that the volume is also expressible via a determinant formula
of Basso-Dixon type. Finally, we show how the fishnet integrals can be written
in terms of iterated integrals naturally attached to the Calabi-Yau varieties.Comment: 42 page
Photoassociation and coherent transient dynamics in the interaction of ultracold rubidium atoms with shaped femtosecond pulses - I. Experiment
We experimentally investigate various processes present in the
photoassociative interaction of an ultracold atomic sample with shaped
femtosecond laser pulses. We demonstrate the photoassociation of pairs of
rubidium atoms into electronically excited, bound molecular states using
spectrally cut femtosecond laser pulses tuned below the rubidium D1 or D2
asymptote. Time-resolved pump-probe spectra reveal coherent oscillations of the
molecular formation rate, which are due to coherent transient dynamics in the
electronic excitation. The oscillation frequency corresponds to the detun-ing
of the spectral cut position to the asymptotic transition frequency of the
rubidium D1 or D2 lines, respectively. Measurements of the molecular
photoassociation signal as a function of the pulse energy reveal a non-linear
dependence and indicate a non-perturbative excitation process. Chirping the
association laser pulse allowed us to change the phase of the coherent
transients. Furthermore, a signature for molecules in the electronic ground
state is found, which is attributed to molecule formation by femtosecond
photoassociation followed by spontaneous decay. In a subsequent article [A.
Merli et al., submitted] quantum mechanical calculations are presented, which
compare well with the experimental data and reveal further details about the
observed coherent transient dynamics
A hyperelastic model for simulating cells in flow
In the emerging field of 3D bioprinting, cell damage due to large
deformations is considered a main cause for cell death and loss of
functionality inside the printed construct. Those deformations, in turn,
strongly depend on the mechano-elastic response of the cell to the hydrodynamic
stresses experienced during printing. In this work, we present a numerical
model to simulate the deformation of biological cells in arbitrary
three-dimensional flows. We consider cells as an elastic continuum according to
the hyperelastic Mooney-Rivlin model. We then employ force calculations on a
tetrahedralized volume mesh. To calibrate our model, we perform a series of
FluidFM(R) compression experiments with REF52 cells demonstrating that all
three parameters of the Mooney-Rivlin model are required for a good description
of the experimental data at very large deformations up to 80%. In addition, we
validate the model by comparing to previous AFM experiments on bovine
endothelial cells and artificial hydrogel particles. To investigate cell
deformation in flow, we incorporate our model into Lattice Boltzmann
simulations via an Immersed-Boundary algorithm. In linear shear flows, our
model shows excellent agreement with analytical calculations and previous
simulation data.Comment: 15 pages, 9 figures, Supplementary information included.
Unfortunately, the journal version misses an important contributor. The
correct author list is the one given in this document. Biomech Model
Mechanobiol (2020
Coherent control with shaped femtosecond laser pulses applied to ultracold molecules
We report on coherent control of excitation processes of translationally
ultracold rubidium dimers in a magneto-optical trap by using shaped femtosecond
laser pulses. Evolution strategies are applied in a feedback loop in order to
optimize the photoexcitation of the Rb2 molecules, which subsequently undergo
ionization or fragmentation. A superior performance of the resulting pulses
compared to unshaped pulses of the same pulse energy is obtained by
distributing the energy among specific spectral components. The demonstration
of coherent control to ultracold ensembles opens a path to actively influence
fundamental photo-induced processes in molecular quantum gases
A Recovery-Oriented Approach for an Acute Psychiatric Ward: Is It Feasible and How Does It Affect Staff Satisfaction?
To evaluate professionals' attitudes to recovery and coercion, as well their satisfaction with working conditions before and after the implementation of a recovery-oriented ward concept on an admission ward. Longitudinal study design with two measurement times of the study sample, with a control group assessed at study end. Evaluating the implementation of the recovery concept, attitudes towards recovery, coercion, perceptions of the ward and working satisfaction were assessed with questionnaires and computed using Chi square and ANOVA variance analyses. The members of the intervention ward (n=17) did not differ from the control group (n=21), except that control group members were younger. The recovery-orientation of the study ward (ROSE questionnaire) increased significantly (alpha level=0.05) from study begin to study end (p=0.003), and compared to the control group (p=0.002). The attitudes towards coercion did not change significantly in the intervention group, but did so compared to the control group. The contentedness (GMI) and the satisfaction with working conditions (ABB) of the intervention group members compared to control group was significantly higher (GMI: p=0.004, ABB subscale working conditions: p=0.043, satisfaction: p=0.023). The study indicates that recovery-oriented principles can be implemented even in an acute admission ward, increasing team satisfaction with work, while attitudes towards coercion did not change significantly within this single-unit project
Nipple Discharge: Role of Ductoscopy in Comparison with Standard Diagnostic Tests
Background: This study aims to assess the role of ductoscopy for detecting intraductal anomalies in patients with nipple discharge in comparison to conventional tests and to find an effective combination of both approaches. Materials and Methods: Prior to duct excision, ductoscopy was performed in 97 women. Histologic and all other diagnostic results were compared. Sensitivity, specificity, and efficiency were calculated for all methods. These parameters were also calculated for all possible test combinations in 12 patients who had completed all tests. Results: Breast sonography reached the highest sensitivity (64.1%) and efficiency (64%); mammography had the highest specificity (100%). The sensitivity of ductoscopy was 53.2%, its specificity 60%, and its efficiency 55.1%. Among combinations of all methods, the combination ductoscopy + galactography was the most sensitive (80%). Mammography, magnetic resonance imaging, and ductoscopy were each 100% specific. Ductoscopy was the most efficient (75%) single method. Conclusion: Ductoscopy is a valuable test for diagnosing intraductal lesions in patients with nipple discharge. It is more efficient than conventional tests in patients undergoing all tests
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