TY - JOUR A1 - Heiling, Sven A1 - Knutti, Nadine A1 - Scherr, Franziska A1 - Geiger, Jörg A1 - Weikert, Juliane A1 - Rose, Michael A1 - Jahns, Roland A1 - Ceglarek, Uta A1 - Scherag, André A1 - Kiehntopf, Michael T1 - Metabolite ratios as quality indicators for pre-analytical variation in serum and EDTA plasma JF - Metabolites N2 - In clinical diagnostics and research, blood samples are one of the most frequently used materials. Nevertheless, exploring the chemical composition of human plasma and serum is challenging due to the highly dynamic influence of pre-analytical variation. A prominent example is the variability in pre-centrifugation delay (time-to-centrifugation; TTC). Quality indicators (QI) reflecting sample TTC are of utmost importance in assessing sample history and resulting sample quality, which is essential for accurate diagnostics and conclusive, reproducible research. In the present study, we subjected human blood to varying TTCs at room temperature prior to processing for plasma or serum preparation. Potential sample QIs were identified by Ultra high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) based metabolite profiling in samples from healthy volunteers (n = 10). Selected QIs were validated by a targeted MS/MS approach in two independent sets of samples from patients (n = 40 and n = 70). In serum, the hypoxanthine/guanosine (HG) and hypoxanthine/inosine (HI) ratios demonstrated high diagnostic performance (Sensitivity/Specificity > 80%) for the discrimination of samples with a TTC > 1 h. We identified several eicosanoids, such as 12-HETE, 15-(S)-HETE, 8-(S)-HETE, 12-oxo-HETE, (±)13-HODE and 12-(S)-HEPE as QIs for a pre-centrifugation delay > 2 h. 12-HETE, 12-oxo-HETE, 8-(S)-HETE, and 12-(S)-HEPE, and the HI- and HG-ratios could be validated in patient samples. KW - quality indicators KW - biomarker KW - hypoxanthine KW - inosine KW - guanosine KW - eicosanoids KW - time-to-centrifugation KW - pre-analytical variation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246261 SN - 2218-1989 VL - 11 IS - 9 ER - TY - JOUR A1 - Gottschalk, Michael G. A1 - Richter, Jan A1 - Ziegler, Christiane A1 - Schiele, Miriam A. A1 - Mann, Julia A1 - Geiger, Maximilian J. A1 - Schartner, Christoph A1 - Homola, György A. A1 - Alpers, Georg W. A1 - Büchel, Christian A1 - Fehm, Lydia A1 - Fydrich, Thomas A1 - Gerlach, Alexander L. A1 - Gloster, Andrew T. A1 - Helbig-Lang, Sylvia A1 - Kalisch, Raffael A1 - Kircher, Tilo A1 - Lang, Thomas A1 - Lonsdorf, Tina B. A1 - Pané-Farré, Christiane A. A1 - Ströhle, Andreas A1 - Weber, Heike A1 - Zwanzger, Peter A1 - Arolt, Volker A1 - Romanos, Marcel A1 - Wittchen, Hans-Ulrich A1 - Hamm, Alfons A1 - Pauli, Paul A1 - Reif, Andreas A1 - Deckert, Jürgen A1 - Neufang, Susanne A1 - Höfler, Michael A1 - Domschke, Katharina T1 - Orexin in the anxiety spectrum: association of a HCRTR1 polymorphism with panic disorder/agoraphobia, CBT treatment response and fear-related intermediate phenotypes JF - Translational Psychiatry N2 - Preclinical studies point to a pivotal role of the orexin 1 (OX1) receptor in arousal and fear learning and therefore suggest the HCRTR1 gene as a prime candidate in panic disorder (PD) with/without agoraphobia (AG), PD/AG treatment response, and PD/AG-related intermediate phenotypes. Here, a multilevel approach was applied to test the non-synonymous HCRTR1 C/T Ile408Val gene variant (rs2271933) for association with PD/AG in two independent case-control samples (total n = 613 cases, 1839 healthy subjects), as an outcome predictor of a six-weeks exposure-based cognitive behavioral therapy (CBT) in PD/AG patients (n = 189), as well as with respect to agoraphobic cognitions (ACQ) (n = 483 patients, n = 2382 healthy subjects), fMRI alerting network activation in healthy subjects (n = 94), and a behavioral avoidance task in PD/AG pre- and post-CBT (n = 271). The HCRTR1 rs2271933 T allele was associated with PD/AG in both samples independently, and in their meta-analysis (p = 4.2 × 10−7), particularly in the female subsample (p = 9.8 × 10−9). T allele carriers displayed a significantly poorer CBT outcome (e.g., Hamilton anxiety rating scale: p = 7.5 × 10−4). The T allele count was linked to higher ACQ sores in PD/AG and healthy subjects, decreased inferior frontal gyrus and increased locus coeruleus activation in the alerting network. Finally, the T allele count was associated with increased pre-CBT exposure avoidance and autonomic arousal as well as decreased post-CBT improvement. In sum, the present results provide converging evidence for an involvement of HCRTR1 gene variation in the etiology of PD/AG and PD/AG-related traits as well as treatment response to CBT, supporting future therapeutic approaches targeting the orexin-related arousal system. KW - human behaviour KW - molecular neuroscience KW - personalized medicine KW - predictive markers KW - psychiatric disorders Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227479 VL - 9 ER - TY - THES A1 - Geiger, Michael T1 - Monetary Policy in China: Institutions, Targets, Instruments and Strategies T1 - Geldpolitik in China: Institutionen, Ziele, Instrumente und Strategien N2 - China’s monetary policy aims to reach two final targets: a paramount economical target (i.e. price stability) and a less important political target (i.e. economic growth). The main actor of monetary policy is the central bank, the People’s Bank of China (PBC). But the PBC is a non-independent central bank. The State Council approves the goals of monetary policy. Very limited instrument independence means that interest rates cannot be set at the PBC’s discretion, and in-sufficient personal independence fails to insulate central bank officials from political influence. Monetary policy in China applies to two sets of monetary policy instruments: (i) instruments of the PBC; and (ii) non-central bank policy instruments. The instruments of the PBC include price-based indirect and quantity-based direct instruments. Non-central bank policy instruments include price and wage controls. The simultaneous usage of all these instruments leads to various distortions that ultimately prevent the interest rate channel of monetary transmission from functioning. Moreover, the strong influences of quantity-based direct instruments and non-central bank policy instruments bring into question the approach of indirect monetary policy in general. The PBC officially follows the monetary targeting approach with monetary aggregates as intermediate targets. Domestic loan growth and the exchange rate are defined as additional intermediate targets. In an in-depth analysis of the intermediate targets two main issues are primarily explored: (i) Are the intermediate targets of the Chinese monetary policy controllable? (ii) Is a sufficient relationship between these targets and the inflation rate observable? It is then shown that monetary aggregates are very difficult to control, but they have a satisfactory relationship with the inflation rate. Similarly, domestic loan growth is difficult to control – a fact largely attributed to the interest rate elasticity of loans – while there is a particularly close relationship between credit growth and the inflation rate. The exchange rate as an intermediate target can be controlled through foreign exchange market interventions; at the same time the exchange rate appears to have a significant relationship to the domestic inflation rate. Discussing the special issue of sterilizing foreign exchange inflows, the study concludes that between 2002 and 2008 not only no costs were incurred by sterilization operations, but that the central bank was actually able to realize a profit through foreign exchange market interventions. Based on this, it is concluded that the exchange rate target has not adversely affected the domestic orientation of monetary policy on the whole. The final part of the study examines whether there are any alternative monetary policy approaches that may be able to describe the policy approach in China; special focus is placed on nominal GDP targeting, the Taylor rule, and inflation targeting. A literature review reveals that the concept of nominal GDP targeting may be able to detect inflationary tendencies in the economy and, in combination with other indicators, it could be a suitable concept to assess the overall economic situation. The author calculates a Taylor rule for China from 1994 to 2008 and concludes that there is no close relationship between the PBC lending and the Taylor rate. The author then designs an augmented Taylor rule expanded to include a credit component (credit-augmented Taylor rule). The study shows that the augmented Taylor rule does not perform much better than the original one, but that it maps high inflationary periods relatively well. This is attributed to direct interventions into the credit markets, which have played a major role in combating inflationary cycles over the past decades. The analysis ends with an introduction of the concept of inflation targeting and an examination of whether this could describe monetary policy in China. It is clear that the PBC does not currently follow the inflation targeting approach, although the Chinese authorities could actually be able to influence inflation expectations effectively, not least through direct instruments such as price controls. The author notes that the PBC indeed had a good track record of fighting inflation between 1994 and 2008, and that this may now indicate a good time to think about introducing inflation targeting in China. The central conclusion of the study is that the proven gradual approach to economic and monetary reforms in China is reaching its limit. To break the vicious cycle that relies on the continuous use of quantity-based instruments to compensate for the ineffective price-based instruments – which in turn arises from the simultaneous use of both types of instruments – a complete shift away from quantity-based instruments is needed. Only then the approach of indirect monetary policy, which was officially introduced in 1998, could come into full play. N2 - Chinas Geldpolitik verfolgt zwei Endziele: Ein alles überragendes wirtschaftliches Ziel (d.h. Preisstabilität) und ein weniger wichtiges politisches Ziel (d.h. Wirtschaftswachstum). Der Hauptakteur der Geldpolitik ist die Zentralbank, die People's Bank of China (PBC). Aber die PBC ist eine nicht-unabhängige Zentralbank. Der Staatsrat genehmigt die Ziele der Geldpolitik, und eine sehr begrenzte Instrumenten-Unabhängigkeit bedeutet, dass die Zinsen nicht vollständig nach dem Ermessen der PBC festgelegt werden können. Die ungenügende personelle Unabhängigkeit der Zentralbank schafft es nicht, die Amtsträger dem politischen Einfluss zu entziehen. Der Geldpolitik in China stehen zwei Arten von geldpolitischen Instrumenten zur Verfügung: (i) Instrumente der PBC; und (ii) Politische nicht-Notenbank Instrumente. Die Instrumente der PBC beinhalten preis-basierte indirekte und quantität-basierte direkte Instrumente. Zu den politischen nicht-Notenbank Instrumenten zählen Preis- und Lohnkontrollen. Die gleichzeitige Nutzung dieser Instrumente führt zu vielerei Verzerrungen, die letztlich verhindern, dass der Zinskanal des monetären Transmissionsmechanismus funktionieren kann. Darüber hinaus stellen die starken Einflüsse der quantität-basierten direkten Instrumente und der politischen nicht-Notenbank Instrumente den Ansatz der indirekten Geldpolitik im Allgemeinen in Frage. KW - Geldpolitik KW - China KW - Geldmengenpolitik KW - Inflation Targeting KW - Preisberwachung KW - Lohnkontrolle KW - Taylor-Regel KW - Geldmengensteuerung KW - Notenbank KW - People's Bank of China KW - Monetary Policy KW - Window Guidance KW - China KW - Monetary Sterilisation Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69945 ER - TY - JOUR A1 - Geiger, Michael A1 - Acharya, Rachana A1 - Reutter, Eric A1 - Ferschke, Thomas A1 - Zschieschang, Ute A1 - Weis, Jürgen A1 - Pflaum, Jens A1 - Klauk, Hagen A1 - Weitz, Ralf Thomas T1 - Effect of the Degree of the Gate‐Dielectric Surface Roughness on the Performance of Bottom‐Gate Organic Thin‐Film Transistors JF - Advanced Materials Interfaces N2 - In organic thin‐film transistors (TFTs) fabricated in the inverted (bottom‐gate) device structure, the surface roughness of the gate dielectric onto which the organic‐semiconductor layer is deposited is expected to have a significant effect on the TFT characteristics. To quantitatively evaluate this effect, a method to tune the surface roughness of a gate dielectric consisting of a thin layer of aluminum oxide and an alkylphosphonic acid self‐assembled monolayer over a wide range by controlling a single process parameter, namely the substrate temperature during the deposition of the aluminum gate electrodes, is developed. All other process parameters remain constant in the experiments, so that any differences observed in the TFT performance can be confidently ascribed to effects related to the difference in the gate‐dielectric surface roughness. It is found that an increase in surface roughness leads to a significant decrease in the effective charge‐carrier mobility and an increase in the subthreshold swing. It is shown that a larger gate‐dielectric surface roughness leads to a larger density of grain boundaries in the semiconductor layer, which in turn produces a larger density of localized trap states in the semiconductor. KW - grain boundaries KW - organic thin‐film transistors KW - surface roughness Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-214830 VL - 7 IS - 10 ER - TY - JOUR A1 - Geiger, Nina A1 - Diesendorf, Viktoria A1 - Roll, Valeria A1 - König, Eva-Maria A1 - Obernolte, Helena A1 - Sewald, Katherina A1 - Breidenbach, Julian A1 - Pillaiyar, Thanigaimalai A1 - Gütschow, Michael A1 - Müller, Christa E. A1 - Bodem, Jochen T1 - Cell type-specific anti-viral effects of novel SARS-CoV-2 main protease inhibitors JF - International Journal of Molecular Sciences N2 - Recently, we have described novel pyridyl indole esters and peptidomimetics as potent inhibitors of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) main protease. Here, we analysed the impact of these compounds on viral replication. It has been shown that some antivirals against SARS-CoV-2 act in a cell line-specific way. Thus, the compounds were tested in Vero, Huh-7, and Calu-3 cells. We showed that the protease inhibitors at 30 µM suppress viral replication by up to 5 orders of magnitude in Huh-7 cells, while in Calu-3 cells, suppression by 2 orders of magnitude was achieved. Three pyridin-3-yl indole-carboxylates inhibited viral replication in all cell lines, indicating that they might repress viral replication in human tissue as well. Thus, we investigated three compounds in human precision-cut lung slices and observed donor-dependent antiviral activity in this patient-near system. Our results provide evidence that even direct-acting antivirals may act in a cell line-specific manner. KW - SARS-CoV-2 KW - protease inhibitors KW - cell line specificity pyridyl indole carboxylates KW - azapeptide nitriles KW - peptidomimetics Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-304034 SN - 1422-0067 VL - 24 IS - 4 ER - TY - JOUR A1 - Geiger, Julia A1 - Hirtler, Daniel A1 - Gottfried, Kristina A1 - Rahman, Ozair A1 - Bollache, Emilie A1 - Barker, Alex J. A1 - Markl, Michael A1 - Stiller, Brigitte T1 - Longitudinal Evaluation of Aortic Hemodynamics in Marfan Syndrome: New Insights from a 4D Flow Cardiovascular Magnetic Resonance Multi-Year Follow-Up Study JF - Journal of Cardiovascular Magnetic Resonance N2 - Background The aim of this 4D flow cardiovascular magnetic resonance (CMR) follow-up study was to investigate longitudinal changes in aortic hemodynamics in adolescent patients with Marfan syndrome (MFS). Methods 4D flow CMR for the assessment of in-vivo 3D blood flow with full coverage of the thoracic aorta was performed twice (baseline scan t1/follow-up scan t2) in 19 adolescent MFS patients (age at t1: 12.7 ± 3.6 years, t2: 16.2 ± 4.3 years) with a mean follow-up duration of 3.5 ± 1.2 years. Ten healthy volunteers (24 ± 3.8 years) served as a control group. Data analysis included aortic blood flow visualization by color-coded 3D pathlines, and grading of flow patterns (helices/vortices) on a 3-point scale (none, moderate, severe; blinded reading, 2 observers). Regional aortic peak systolic velocities and systolic 3D wall shear stress (WSS) along the entire aortic wall were quantified. Z-Scores of the aortic root and proximal descending aorta (DAo) were assessed. Results Regional systolic WSS was stable over the follow-up duration, except for a significant decrease in the proximal inner DAo segment (p = 0.02) between t1 and t2. MFS patients revealed significant lower mean systolic WSS in the proximal inner DAo compared with volunteers (0.78 ± 0.15 N/m\(^{2}\)) at baseline t1 (0.60 ± 0.18 N/m\(^{2}\); p = 0.01) and follow-up t2 (0.55 ± 0.16 N/m\(^{2}\); p = 0.001). There were significant relationships (p < 0.01) between the segmental WSS in the proximal inner DAo, DAo Z-scores (r = −0.64) and helix/vortex pattern grading (r = −0.55) at both t1 and t2. The interobserver agreement for secondary flow patterns assessment was excellent (Cohen’s k = 0.71). Conclusions MFS patients have lower segmental WSS in the inner proximal DAo segment which correlates with increased localized aberrant vortex/helix flow patterns and an enlarged diameter at one of the most critical sites for aortic dissection. General aortic hemodynamics are stable but these subtle localized DAo changes are already present at young age and tend to be more pronounced in the course of time. KW - Marfan syndrome KW - wall shear stress KW - hemodynamics KW - 4D flow cardiovascular magnetic resonance KW - follow-up KW - aorta Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171119 VL - 19 IS - 33 ER -