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Large Numbers for Small Children: Up to What Age Do Infants Benefit from a Longer Echo Time in Cerebral T2 MRI Sequences?
No full textIn newborns, white matter shows a high T2-weighted (T2w) signal in MRI with poor grey–white matter contrast. To increase this contrast, an extremely long echo time (TE) is used in the examination of children. It is not known up to what age this long TE should be used. The purpose of this study was to find up to what age a long TE should be used in infants. In the prospective study, 101 infants (0–18 months) underwent cranial MRI at 3 Tesla. T2-weighted Fast Spin Echo sequences with long TE (200 ms) and medium TE (100 ms) were used. The signal intensities of the cortex and white matter were measured and the grey–white matter contrast (MC) was calculated. A cut-off age was determined. The T2w sequences with long TE had a statistically significantly higher MC until the age of six months (medium TE: 0.1 ± 0.05, Long TE: 0.19 ± 0.07; p < 0.001). After the tenth month, the T2w sequence with medium TE provided significantly better MC (Medium TE: 0.1 ± 0.05; long TE: 0.05 ± 0.4; p < 0.001). The use of a long TE is only helpful in the first six months of life. After the tenth month of life, a medium TE should be favored as is used in adult brain MRI
Neighbourhood species richness and drought-tolerance traits modulate tree growth and δ13C responses to drought
No full textMixed-species forests are promoted as a forest management strategy for climate
change adaptation, but whether they are more resistant to drought than monospecific
forests remains contested. In particular, the trait-based mechanisms driving the role of
tree diversity under drought remain elusive.
• Using tree cores from a large-scale biodiversity experiment, we investigated tree
growth and physiological stress responses (i.e. increase in wood carbon isotopic ratio;
δ13 C) to changes in climate-induced water availability (wet to dry years) along gradi-
ents in neighbourhood tree species richness and drought-tolerance traits. We hypothe-
sized that neighbourhood species richness increases growth and decreases δ13 C and
that these relationships are modulated by the abiotic (i.e. climatic conditions) and the
biotic context. We characterised the biotic context using drought-tolerance traits of
focal trees and their neighbours. These traits are related to cavitation resistance versus
resource acquisition and stomatal control.
• Tree growth increased with neighbourhood species richness. However, we did not
observe a universal relief of water stress in species-rich neighbourhoods. The effects of
neighbourhood species richness and climate on growth and δ13 C were modulated by
the traits of focal trees and the traits of their neighbours. At either end of each
drought-tolerance gradient, species responded in opposing directions during dry and
wet years.
• We show that species’ drought-tolerance traits can explain the strength and nature of
biodiversity–ecosystem functioning relationships in experimental tree communities
experiencing drought. Mixing tree species can increase growth but may not universally
relieve drought stress
Patientenbezogene Prädiktoren für die Präferenz und den Erhalt einer adipositaschirurgischen Operation
No full textAdipositas ist eine weltweit zunehmende Zivilisationskrankheit mit zahlreichen gesundheitlichen Risiken, für die die Adipositaschirurgie (OS von engl. obesity surgery) derzeit die effektivste Therapie darstellt. Die Entscheidung für eine adipositaschirurgische Operation ist komplex und muss unter anderem die Präferenz der Patient:innen berücksichtigen. Diese Arbeit untersuchte erstmals, wie sich die Präferenz für Adipositaschirurgie im Verlauf einer einjährigen konservativ-behavioralen Gewichtsreduktionstherapie (BWLT von engl. behavioral weight-loss therapy) entwickelt. In einer Stichprobe von 431 Patient:innen eines krankenkassenfinanzierten BWLT- Programms mit Möglichkeit zur OS zeigte sich, dass zu Therapiebeginn nur wenige OS präferierten, dieser Anteil jedoch nach der BWLT deutlich anstieg. Patient:innen mit konstant bestehender oder im Verlauf neu aufgetretener Präferenz für OS wiesen tendenziell ungünstigere anthropometrische, psychologische und medizinische Charakteristika auf als Patient:innen ohne oder mit nur vor Beginn der BWLT bestehender Präferenz für OS. Eine Präferenz für OS vor Therapiebeginn sagte den Erhalt einer adipositaschirurgischen Operation nach der BWLT vorher, vermittelt durch einen höheren BMI vor und nach der BWLT, jedoch nicht durch einen geringeren prozentualen Körpergewichtsverlust. Die Ergebnisse unterstreichen die Bedeutung der Patientenpräferenz für OS und könnten klinisch zur Individualisierung der BWLT klinisch genutzt werden.:Tabellenverzeichnis
Abkürzungsverzeichnis
1. Einführung
1.1. Adipositas
1.1.1. Definition und Epidemiologie
1.1.2. Ätiologie
1.1.3. Gesundheitliche Auswirkungen
1.1.4. Behandlung
1.2. Adipositaschirurgie
1.2.1. Indikation
1.2.2. Adipositaschirurgische Verfahren
1.2.3. Epidemiologie
1.2.4. Sicherheit
1.2.5. Risiken
1.2.6. Physische Verbesserungen
1.2.7. Psychische Verbesserungen
1.2.8. Charakteristika der Patient:innen, die eine adipositaschirurgische
Operation erhalten
1.2.9. Gründe für die Entscheidung für eine adipositaschirurgische Operation
1.2.10. Barrieren für die Entscheidung für eine adipositaschirurgische
Operation
1.3 Patientenpräferenz für Adipositaschirurgie
1.3.1 Bedeutung der Patientenpräferenz für eine adipositaschirurgische
Operation
1.3.2 Bisherige Evidenz und bestehende Forschungslücken
1.3.3. Zielsetzungen und Hypothesen der Arbeit
2. Publikation
3. Zusammenfassung der Arbeit
4. Literaturverzeichnis
5. Darstellung des eigenen Beitrags
6. Selbstständigkeitserklärung
7. Lebenslauf
8. Publikationen
9. Danksagun
Should Transformation Products Change the Way We Manage Chemicals?
No full textWhen chemical pollutants enter the environment, they can undergo diverse transformation processes, forming a wide range of transformation products (TPs), some of them benign and others more harmful than their precursors. To date, the majority of TPs remain largely unrecognized and unregulated, particularly as TPs are generally not part of routine chemical risk or hazard assessment. Since many TPs formed from oxidative processes are more polar than their precursors, they may be especially relevant in the context of persistent, mobile, and toxic (PMT) and very persistent and very mobile (vPvM) substances, which are two new hazard classes that have recently been established on a European level. We highlight herein that as a result, TPs deserve more attention in research, chemicals regulation, and chemicals management. This perspective summarizes the main challenges preventing a better integration of TPs in these areas: (1) the lack of reliable high-throughput TP identification methods, (2) uncertainties in TP prediction, (3) inadequately considered TP formation during (advanced) water treatment, and (4) insufficient integration and harmonization of TPs in most regulatory frameworks. A way forward to tackle these challenges and integrate TPs into chemical management is proposed
Text mining uncovers the unique dynamics of socio-economic impacts of the 2018–2022 multi-year drought in Germany
No full textDroughts often lead to cross-sectoral and interconnected socio-economic impacts, affecting human well-being, ecosystems, and economic development. Extended drought periods, such as the 2018–2022 event in Germany, amplify these impacts due to temporal carry-over effects. Yet, our understanding of drought impact dynamics during increasingly frequent multi-year drought periods is still in its infancy. In this study, we analyse the socio-economic impacts of the 2018–2022 multi-year drought in Germany and compare them to previous single-year events. Leveraging text-mining tools, we derive a dataset covering impacts reported by 260 news outlets on agriculture, forestry, livestock, waterways, aquaculture, fire, and social impacts spanning 2000 to 2022. We introduce the concept of drought impact profiles (DIPs) to describe spatio-temporal patterns of the reported co-occurrences of impacts. We employ a clustering algorithm to detect these DIPs and then use sequence mining and statistical tests to analyse spatio-temporal trends. Our results reveal that the 2018–2022 multi-year drought event had distinct impact patterns compared to prior single-year droughts regarding their spatial extent, impact diversity, and prevalent impact types. For the multi-year drought period, we identify shifts in how impacts have been perceived regionally, especially focusing on legacy and cascading effects on forestry and social activities. Also, we show how regional differences in relevant impacts are controlled by different land-cover types. Our findings enhance the understanding of the dynamic nature of drought impacts, highlighting the potential of text-mining techniques to study drought impact dynamics. The insights gained underscore the need for different strategies in managing multi-year droughts compared to single-year events
Variability in the properties of the distribution of the relative humidity with respect to ice: implications for contrail formation
No full textRelative humidity with respect to ice (RHi) is a key variable in the formation of cirrus clouds and contrails. We document its probability density function (PDF) using long-term Measurements of Ozone, Water Vapour, Carbon Monoxide and Nitrogen Oxides by In-Service Airbus Aircraft (MOZAIC) and the In-service Aircraft for a Global Observing System (IAGOS) observations over the period 1995–2022 in the upper troposphere (UT) and the lower stratosphere (LS) between 325 and 175 hPa. The characteristics of the RHi PDF differ in the UT and in the LS of the high-latitude regions (HLs) and mid-latitude regions (MLs) of the Northern Hemisphere. In the LS, this PDF decreases exponentially with increasing RHi. In the UT, it first increases exponentially in subsaturated conditions and then decreases exponentially in supersaturated conditions. Because of these different behaviors, the PDF for the combined UT and LS is bimodal. In contrast to the HLs and the MLs, the RHi PDF in the tropical troposphere decreases exponentially with increasing RHi. The different forms of PDF, in the tropics and in the higher-latitude regions, lead to a global PDF of RHi in subsaturated tropospheric
conditions that is almost uniform. These findings invite caution when using MOZAIC and IAGOS measurements to calibrate large-scale simulations of RHi. The variability in RHi properties associated with that of temperature also has implications for the formation of contrails. We examined the impact of switching fuel (from kerosene to bioethanol or liquid hydrogen) on the frequency of contrail formation using the Schmidt–Appleman criterion.
We show that bioethanol and, to a larger extent, liquid hydrogen would produce more contrails. The impact of a potential change from kerosene to these alternative fuels decreases with decreasing pressure but increases when moving from the higher latitudes of the Northern Hemisphere to the tropics. Finally, we emphasize that investigations of the impact on contrail occurrence frequency as a result of switching from fossil kerosene to more sustainable fuels must be carried out in various meteorological conditions
1,2,4-triazine derived binuclear lead(II) complexes: synthesis, spectroscopic and structural investigations and application in organic light-emitting diodes (OLEDs)
No full textTwo novel binuclear complexes of Pb(II) were synthesized by reacting a 3-(2-pyridyl)-5-(4-methoxyphenyl)-1,2,4-triazine (PMPT) ligand with different anionic co-ligands (1: bromide, 2: acetate and isothiocyanate) in a 1 : 1 molar ratio of PMPT ligands to lead(II) salts. The complexes, [Pb2(μ-PMPT)2Br4] (1) and [Pb2(μ-PMPT)2((μ-CH3COO)2(NCS)2] (2), were characterized using various physicochemical techniques such as CHN analysis, FT-IR spectroscopy, and 1H NMR spectroscopy. Additionally, their structures were determined using single-crystal X-ray diffraction. Based on the obtained structural parameters, complex 1 exhibited a PbN3Br2 environment, while complex 2 displayed a PbN4O3 environment, with holodirected and hemidirected coordination spheres, respectively. Within the crystal network of the complexes, there were interactions involving C–H⋯X (X: O, S, N) as well as π–π stacking. The Pb(II) complexes were further investigated for their potential use as the emitting layer in organic light-emitting devices (OLEDs). The current–voltage and luminescence-voltage characteristics, as well as the electroluminescence (EL) properties of the complexes, were studied
A Comparison of Different Intensive Care Unit Definitions Derived from the German Administrative Data Set: A Methodological, Real-World Data Analysis from 86 Helios Hospitals
No full textBackground: The intensive care unit (ICU) is a scarce resource in all health care systems, necessitating a well-defined utilization. Therefore, benchmarks are essential; and yet, they are limited due to heterogenous definitions of what an ICU is. This study analyzed the case distribution, patient characteristics, and hospital course and outcomes of 6,204,093 patients in the German Helios Hospital Group according to 10 derived ICU definitions. We aimed to set a baseline for the development of a nationwide, uniform ICU definition. Methods: We analyzed ten different ICU definitions: seven derived from the German administrative data set of claims data according to the German Hospital Remuneration Act, three definitions were taken from the Helios Hospital Group’s own bed classification. For each ICU definition, the size of the respective ICU population was analyzed. Due to similar patient characteristics for all ten definitions, we selected three indicator definitions to additionally test statistically against IQM. Results: We analyzed a total of 5,980,702 completed hospital cases, out of which 913,402 referred to an ICU criterion (14.7% of all cases). A key finding is the significant variability in ICU population size, depending on definitions. The most restrictive definition of only mechanical ventilation (DOV definition) resulted in 111,966 (1.9%) cases; mechanical ventilation plus typical intensive care procedure codes (IQM definition) resulted in 210,147 (3.5%) cases; defining each single bed individually as ICU or IMC (ICUᴧIMC definition) resulted in 411,681 (6.9%) cases; and defining any coded length of stay at ICU (LOSi definition) resulted in 721,293 (12.1%) cases. Further testing results for indicator definitions are reported. Conclusions: The size of the population, utilization rates, outcomes, and capacity assumptions clearly depend on the definition of ICU. Therefore, the underlying ICU definition should be stated when making any comparisons. From previous studies, we anticipated that 25–30% of all ICU patients should be mechanically ventilated, and therefore, we conclude that the ICUᴧIMC definition is the most plausible approximation. We suggest a mandatory application of a clearly defined ICU term for all hospitals nationwide for improved benchmarking and data analysis
Gelatin-Based Liver Phantoms for Training Purposes: A Cookbook Approach
No full textBackground: Patients with liver pathology benefit from image-guided interventions. Training for interventional procedures is recommended to be performed on liver phantoms until a basic proficiency is reached. In the last 40 years, several attempts have been made to develop materials to mimic the imaging characteristics of the human liver in order to create liver phantoms. There is still a lack of accessible, reproducible and cost-effective soft liver phantoms for image-guided procedure training. Methods: Starting from a CT-scan DICOM file, we created a 3D-printed liver mold using InVesalius (Centro de Tecnologia da informação Renato Archer CTI, InVesalius 3 open-source software, Campinas, Brazil) for segmentation, Autodesk Fusion 360 with Netfabb (Autodesk software company, Fusion 360 2.0.19426 with Autodesk Netfabb Premium 2023.0 64-Bit Edition, San Francisco, CA, USA) for 3D modeling and Stratasys Fortus 380 mc 3D printer (Stratasys 3D printing company, Fortus 380 mc 3D printer, Minneapolis, MN, USA). Using the 3D-printed mold, we created 14 gelatin-based liver phantoms with 14 different recipes, using water, cast sugar and dehydrated gelatin, 32% fat bovine milk cream with intravenous lipid solution and technical alcohol in different amounts. We tested all these phantoms as well as ex vivo pig liver and human normal, fatty and cirrhotic liver by measuring the elasticity, shear wave speed, ultrasound attenuation, CT-scan density, MRI signal intensity and fracture force. We assessed the results of the testing performed, as well as the optical appearance on ultrasound, CT and MRI, in order to find the best recipe for gelatin-based phantoms for image-guided procedure training. Results: After the assessment of all phantom recipes, we selected as the best recipe for transparent phantoms one with 14 g of gelatin/100 mL water and for opaque phantom, the recipes with 25% cream. Conclusions: These liver gelatin-based phantom recipes are an inexpensive, reproducible and accessible alternative for training in image-guided and diagnostic procedures and will meet most requirements for valuable training
A Single-Centre Retrospective Analysis of Pregnancies with Placenta Accreta Spectrum (PAS): From One-Step Surgery towards Two-Step Surgical Approach
No full textBackground: Placenta accreta spectrum (PAS) can be the cause of major morbidity and its optimal management is still controversial. The aim of this study was to compare the traditional one-step surgery with a two-step surgical approach in which the placenta is left in situ and the second final operation is delayed to minimise blood loss. Methods: We conducted a single-centre retrospective cohort study including all patients managed for PAS between 2007 and 2023. The number of units of red blood cells (RBCs) needed during surgery was the primary outcome used to compare these two approaches. Results: A total of 43 cases were included in this analysis. Twenty of these were managed with the delayed two-step surgical approach, whereas 23 received one-step surgery. The median estimated blood loss during surgery was 2000 mL and 2800 mL for two-step and one-step surgery, respectively (p = 0.095). In the two-step surgical approach, the median number of RBC units transfused during surgery was significantly lower (p = 0.049) and the odds ratio for needing more than four units of RBCs was 0.28 (95%-CI: 0.08–0.98, p = 0.043). A longer interval between the caesarean section and the second operation showed a trend toward lower blood loss (p = 0.065) and was associated with a significantly lower number of RBC units needed during surgery (p = 0.019). Conclusions: Two-step surgery for the treatment of PAS was safe in our cohort and could lead to a reduction in blood transfusion. Leaving the placenta in situ and delaying the final operation represents a possible alternative to traditional caesarean hysterectomy