Technische Universität Dresden: Qucosa
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The DSM-5 panic attack specifier as a severity indicator in mental disorders - Findings from a cross-sectional epidemiological study among adolescents and young adults
No full textBackground:
Lifetime panic attacks (PAs) have been associated with a range of mental disorders and increased disorder severity. In DSM-5, PAs can be used as a descriptive specifier across disorders. This study investigates frequency and clinical implications of PAs and Fearfull Spells (FS) occurring simultaneously with mental disorders in community youth.
Methods:
Symptoms and diagnoses of DSM-5 mental disorders including time-related and clinical severity information were assessed from 11/2015–12/2016 in a random sample of 14–21 year olds from Dresden, Germany (N = 1,180).
Results:
Lifetime prevalence estimates for PAs were highest among participants with lifetime agoraphobia (60.2 %) and separation anxiety disorder (sepAD, 46.0 %). Only 4.8 % of participants with any mental disorder fulfilled the criteria of the DSM-5 PA specifier (simultaneous PAs without a co-occurring panic disorder (PD)), mostly participants with sepAD (12.8 %) and posttraumatic stress disorder (10.7 %). Averaged across all disorders, simultaneous PAs/FSs were associated with lower mental health, higher mental health impairment and more service utilization compared to no PAs/FSs and partly also to lifetime PAs/FSs.
Limitations:
Retrospective self-report data could be affected by recall bias. Low case numbers limit statistical power.
Conclusions:
The present findings support the use of PAs/FSs as transdiagnostic DSM-5 specifier, as PAs/FSs occurring simultaneously with mental disorders are descriptively associated with severity indicators. However, the exclusion of PD cases results in a limited proportion of general population youth for which the specifier applies. Larger prospective epidemiological studies could clarify the time course of PAs/FSs, PD and other mental disorders and their effects on severity and course
Mapping Wildfire Scares – NDVI vs. NBR vs. AFRI
No full textIn recent years, wildfires have become serious human and environmental concerns for several reasons. Most importantly, they threaten human life, flora, and fauna, as well as properties and economic losses. Wildfires are considered one of the worst ecological disturbances to long-term records of vegetation phenology, since landcover alterations are the basis for understanding the biological responses to climate change, such as impacting carbon emissions, at regional to continental scales
Enriching Geohazard Education through Virtual Field Trips us-ing VR and 3D Outcrop Models
No full textThere are many exciting opportunities to create immersive learning experiences using rich 3D digital data of the environment. Immersive virtual field trips can be designed to be student-centred, problem-based, collaborative, and fun. Virtual field trip elements can be introduced as an asynchronous component prior to an inperson field trip as a preparation tool or as a post field trip resource. Virtual trips are also more inclusive, allowing a wide range of students to participate regardless of ability or location. With these benefits in mind and aligning them with University of Leeds’ digital education and sustainability strategies, we created a virtual geohazards field trip for the MSc Engineering Geology programme exploring the Jurassic Coast in SW England. The aim of this contribution is to share the development of the resource and an initial assessment of student learning
Some monoidal and module categories in representation theory
No full textIn this thesis, we study several problems from monoidal representation theory. In the first chapter we construct two diagrammatic categories – one monoidal and one module – category in order to describe representations of a quantum symmetric pair. In the second chapter we show that nil Hecke algebras form Hopf algebroids without antipodes via mixed dihedral braid relations. In the third chapter we introduce duodule categories over duoidal categories to provide a ring-theoretic framework for constructing free strict module categories over strict monoidal categories
Methodik und Potenzial der effizienten, gitterfreien Simulation der Spritzreinigung
No full textAutomatisierte Reinigung ist branchenübergreifend stark geprägt durch das Streben nach Effizienz und Umweltschutz. Das gilt insbesondere in der Lebensmittelindustrie, wo der Zeitaufwand für die Reinigung aufgrund hoher Produktstandards und großer Produktvielfalt bis zu 25% der Maschinenarbeitszeit betragen kann. Ein geringer Verbrauch an Reinigungsmitteln, Wasser und Energie sind das erklärte Ziel.
Bisher wird für nichtimmergierte Systeme wie offene Oberflächen und Tanks das große Optimierungspotenzial in der Anpassung der Geometrie und Positionierung der verwendeten Düsen zur Erzeugung zerfallener Spritzstrahlen nicht genutzt. Grund dafür sind die experimentell und erfahrungsgetriebene Auslegungspraxis sowie das sehr eingeschränkte Verständnis der Wirkvorgänge bei der Reinigung. Diese sind im Experiment nur begrenzt räumlich und zeitlich auflösbar sowie bei dünnen Filmen zusätzlich noch schwer zugänglich.
Die numerische Strömungssimulation (CFD) verspricht einen hochaufgelösten Einblick in das Strömungsfeld, wird jedoch nur selten eingesetzt, da aussagekräftige Ergebnisse einen hohen Rechenaufwand erfordern. Simulationsmodelle für die quantitative Reinigungsvorhersage in immergierten Konfigurationen sind zwar vorhanden, typische Simulationen, die den Strahlzerfall beinhalten, nutzen jedoch Großrechner und benötigen Rechenzeiten mehrerer Wochen bis Monate
Triangulating brain alterations in anorexia nervosa: a multimodal investigation of magnetic resonance spectroscopy, morphometry and blood-based biomarkers
No full textThe acute state of anorexia nervosa (AN) is associated with widespread reductions in cortical gray matter (GM) thickness and white matter (WM) volume, suspected changes in myelin content and elevated levels of the neuronal damage marker neurofilament light (NF-L), but the underlying mechanisms remain largely unclear. To gain a deeper understanding of brain changes in AN, we applied a multimodal approach combining advanced neuroimaging methods with analysis of blood-derived biomarkers. In addition to standard measures of cortical GM thickness and WM volume, we analyzed tissue-specific profiles of brain metabolites using multivoxel proton magnetic resonance spectroscopy, T1 relaxation time as a proxy of myelin content leveraging advanced quantitative MRI methods and serum NF-L concentrations in a sample of 30 female, predominately adolescent patients with AN and 30 age-matched female healthy control participants. In patients with AN, we found a reduction in GM cortical thickness and GM total N-acetyl aspartate. The latter predicted higher NF-L levels, which were elevated in AN. Furthermore, GM total choline was elevated. In WM, there were no group differences in either imaging markers, choline levels or N-acetyl aspartate levels. The current study provides evidence for neuronal damage processes as well as for increased membrane lipid catabolism and turnover in GM in acute AN but no evidence for WM pathology. Our results illustrate the potential of multimodal research including tissue-specific proton magnetic resonance spectroscopy analyses to shed light on brain changes in psychiatric and neurological conditions, which may ultimately lead to better treatments
A Quasi-2D Polypyrrole Film with Band-Like Transport Behavior and High Charge-Carrier Mobility
No full textQuasi-2D (q2D) conjugated polymers (CPs) are polymers that consist of linear CP chains assembled through non-covalent interactions to form a layered structure. In this work, the synthesis of a novel crystalline q2D polypyrrole (q2DPPy) film at the air/H2SO4 (95%) interface is reported. The unique interfacial environment facilitates chain extension, prevents disorder, and results in a crystalline, layered assembly of protonated quinoidal chains with a fully extended conformation in its crystalline domains. This unique structure features highly delocalized -electron systems within the extended chains, which is responsible for the low effective mass and narrow electronic bandgap. Thus, the temperature-dependent charge-transport properties of q2DPPy are investigated using the van der Pauw (vdP) method and terahertz time-domain spectroscopy (THz-TDS). The vdP method reveals that the q2DPPy film exhibits a semiconducting behavior with a thermally activated hopping mechanism in long-range transport between the electrodes. Conversely, THz-TDS reveals a band-like transport, indicating intrinsic charge transport up to a record short-range high THz mobility of ≈107.1 cm2 V−1 s−1
Numerical solution of scalar and vector differential equations on surface point clouds
No full textIn this thesis, I present the Surface Discretization-Corrected Particle Strength Exchange (Surface DC-PSE) method for vector-valued partial differential equations (PDEs) on curved surfaces. Surface DC-PSE is a numerical meshfree collocation method for approximating surface differential operators. The method requires a surface point cloud and the surface normal at each point, and provides a mathematically embedding but computationally embedding-free approximation of the fields and their spatial derivatives at each point.
The Surface DC-PSE method is an extension of the DC-PSE method, which is a mesh- free numerical method for approximating Euclidean differential operators. Surface DC-PSE is based on the idea of extending the field constant along the normal into the embedding space, constructing the kernels using both surface and “virtual” extended particles along the normal, and collapsing the resulting ”bulk” kernels into surface ones.
This thesis presents a comprehensive study of the Surface DC-PSE method, including its mathematical formulation, numerical implementation, and verification tests. The results show that the method provides convergent and stable approximations of scalar and vector surface differential operators, and is applicable to a wide range of surfaces.
I also discuss the limitations of the method, including the requirement of a homogeneous point cloud, the sensitivity to particle distributions, and the computational cost of constructing the kernels. Future work is proposed to address these limitations, including modifying the neighborhood construction algorithm, evaluating the accuracy and stability of vector Surface DC-PSE on deforming surfaces, and exploring applications of the method to non-analytical surfaces.
The Surface DC-PSE method has the potential to be used in a wide range of applications, including simulating biological fluid surfaces, studying morphogenesis, and modeling complex surface phenomena. The method provides a robust and reliable framework for approximating surface differential operators, and it provides a basis for further research and development in these and other areas of scientific computing.:Abstract
List of publications
1 Introduction
1.1 Morphogenesis
1.2 Active matter
1.3 Surfaces and curvature in the context of morphogenesis
1.4 Challenges related to surfaces
1.5 State of the art of numerical methods for the solution of surface PDEs
1.5.1 Finite Element methods (FEMs)
1.5.2 Collocation methods
1.5.3 Other methods
1.6 This thesis: an overview
2 Surface differential operators
2.1 Motivation
2.2 Hierarchy of manifolds
2.3 Vector fields: covariant and contravariant notation
2.4 Differentiating vector fields on (curved) manifolds
2.4.1 Parallel transport
2.4.2 Covariant derivative
2.4.3 Covariant derivative in a Riemannian manifold
2.4.4 Summary
2.5 Covariant derivative of hypersurfaces in the Euclidean space
2.6 Curvature
2.6.1 Summary
2.7 A reference case: the S2 sphere
2.7.1 Operator expressions
2.7.2 Eigenfunctions of the scalar and vector Laplacian
2.7.3 An orthonormal basis on the S2 sphere
3 Surface DC-PSE 33
3.1 Particle methods for the approximation of differential operators
3.1.1 DC-PSE: Two-dimensional case
3.1.2 DC-PSE: General case
3.2 Approximating surface differential operators using particle methods
3.3 Surface DC-PSE
3.3.1 Neighborhood construction
3.3.2 Normal extension
3.3.3 Surface kernel construction
3.4 Verification and tests of Surface DC-PSE for scalar fields
3.4.1 Convergence tests
3.4.2 Analysis of the influence of rc and the curvature on the error
3.4.3 Strong scaling of Surface DC-PSE
3.4.4 Comparison with the Surface Finite Element Method
3.5 Reaction-diffusion and patterning with Surface DC-PSE
4 Vector surface PDEs
4.1 Surface DC-PSE for vector fields
4.2 Verification tests of Surface DC-PSE for vector fields
4.2.1 Convergence of vector Laplacian on the unit sphere
4.2.2 Convergence of vector diffusion on unit sphere
4.2.3 Vector diffusion on other shapes
4.3 Flows on surfaces
4.3.1 Verification of combined Surface DC-PSE and EDAC on the unit sphere
4.3.2 Incompressible flow on tori of different curvature
5 Conclusion and Outlook
5.1 Summary
5.2 Limitations
5.3 Looking into the future
Appendices
A Numerical methods for function approximation and PDE solution
A.1 Collocation methods
A.2 Galerkin methods
A.3 Spectral methods
B Differential operators on the unit sphere S2
B.1 Gradient of a scalar
B.2 Gradient of a contravariant vector
B.3 Gradient of a covariant vector
B.4 Divergence of a contravariant vector
B.4.1 Divergence of a covariant vector
B.5 Laplacian (Laplace-Beltrami) of a scalar
B.6 (Connection) Laplacian of a contravariant vector
B.7 Crossproduct
C Scalar spherical harmonics
D Vector spherical harmonics
E An orthonormal basis on the unit S2 sphere
F DC-PSE algorithm: Auxiliary equations
G Simulation parameters
G.1 Fibonacci distribution of points on a sphere
G.2 Error metrics for vector quantities
G.3 Convergence of the Laplace-Beltrami operator on the unit circle and the unit
sphere
G.4 Mean and Gauss curvature of ellipsoid and Stanford bunny
G.5 Analysis of the influence of rc and the curvature on the error of the Laplace-Beltrami operator on the unit sphere
G.6 Comparison with FEMs
G.7 Reaction-diffusion patterns
G.8 Convergence of the connection Laplacian on the unit sphere
G.9 Convergence of the surface divergence operator on the unit sphere
G.10 Convergence of the solution of the vector diffusion equation on the unit sphere G.11 Vector diffusion equation on the torus and a nonic surface
G.12 Verification of combined Surface DC-PSE and EDAC for the solution of the
incompressible surface Navier-Stokes equation on the unit sphere
G.13 Test for the incompressible surface Navier-Stokes equation on tori
G.14 Spherical harmonics for the solution of surface diffusion on the unit sphere
G.15 Error computation using Richardson extrapolation
Bibliography
Index
Acknowledgment
Hierarchically Porous Carbons with Highly Curved Surfaces for Hosting Single Metal FeN4 Sites as Outstanding Oxygen Reduction Catalysts
No full textIron–nitrogen–carbon (Fe–N–C) materials have emerged as a promising alternative to platinum-group metals for catalyzing the oxygen reduction reaction (ORR) in proton-exchange-membrane fuel cells. However, their low intrinsic activity and stability are major impediments. Herein, an Fe–N–C electrocatalyst with dense FeN4 sites on hierarchically porous carbons with highly curved surfaces (denoted as FeN4-hcC) is reported. The FeN4-hcC catalyst displays exceptional ORR activity in acidic media, with a high half-wave potential of 0.85 V (versus reversible hydrogen electrode) in 0.5 m H2SO4. When integrated into a membrane electrode assembly, the corresponding cathode displays a high maximum peak power density of 0.592 W cm−2 and demonstrates operating durability over 30 000 cycles under
harsh H2/air conditions, outperforming previously reported Fe–N–C electrocatalysts. These experimental and theoretical studies suggest that the curved carbon support fine-tunes the local coordination environment, lowers the energies of the Fe d-band centers, and inhibits the adsorption of oxygenated species, which can enhance the ORR activity and stability. This work provides new insight into the carbon nanostructure–activity correlation for ORR catalysis. It also offers a new approach to designing advanced single-metal-site catalysts for energy-conversion applications
Doktorandensymposium der Materialwissenschaft: Tagungsband
No full textMaterialwissenschaftler:innen aus Ústí nad Labem und Dresden trafen sich im Dezember 2024 zum ersten Doktorandensymposium für Materialwissenschaft im Rahmen des Interreg-Projektes MATun zu den Schwerpunkten Fertigungsprozesse, Materialcharakterisierung, Umwelt- und Bio-technologie. Ziel des Symposiums war es, den interdisziplinären Austausch zwischen tschechi-schen und deutschen Forschungseinrichtungen zu fördern und die internationale Zusammenar-beit entlang der sächsisch-tschechischen Grenze zu unterstützen.
Die organisierten Aktivitäten reichten von wissenschaftlichen Präsentationen aktueller For-schungsprojekte über Diskussionsrunden zu möglichen Kooperationen bis hin zu einer Come-to-gether-Veranstaltung bei Tee und weihnachtlichen Snacks. Das Projekt MATun wird vom Pro-gramm Interreg Sachsen – Tschechien 2021-2027 finanziert. Alle Teilnehmerinnen und Teilnehmer - Promovierende, Wissenschaftlerinnen und Wissenschaftler und Studierende der beteiligten Insti-tutionen - nutzten die Gelegenheit, individuelle und neue Kontakte zu knüpfen, sich über aktuelle Forschungsthemen und -methoden auszutauschen, Ansatzpunkte für zukünftige Kooperationen zwischen den verschiedenen Forschungsbereichen und Institutionen zu finden und auch die Ge-meinsamkeiten und Unterschiede zwischen der deutschen und der tschechischen Forschungs-landschaft zu diskutieren.
In diesem Tagungsband werden sowohl die Institutionen mit ihren speziellen Themen vorgestellt sowie aktuelle Forschungsthemen und deren Ergebnisse präsentiert.:Vorwort / Předmluva
1. Projekt MATun / Projekt MATun 2
1.1 Rückblick Symposium / Symposium - přehled 3
1.2 Organisationskomitee / Organizační výbor 3
2 Projektpartner und assoziierte Partner / Projektoví a přidružení partneři 4
2.1 Jan Evangelista Purkyně University in Ústí nad Labem 4
2.1.1 Naturwissenschaftliche Fakultät / Přírodovědecká fakulta 5
2.2 Technische Universität Dresden 11
2.2.1 Institut für Werkstoffwissenschaft / Ústav pro vědu o materiálech 11
2.3 TRANS³Net 14
3 Topics of the presentations 15
3.1 Manufacturing processes 15
3.1.1 Minimum water for maximum strength in semi-dry paper production 15
3.1.2 Horizontal Continuous Casting: optimization of process parameters for a better billet centre quality of high alloyed stainless steels at BGH Freital steel mill – Diploma Thesis 16
3.1.3 Mixing polydisperse granular materials with a focus on segregation 16
3.1.4 Surface Modification of Aluminium Samples Mimicking Scallop Shell Structures and Their Hydrophobic Properties 16
3.1.5 Heat exchange investigations for improved utility of working fluid mixtures in waste heat recovery applications 17
3.1.6 Calorimetric measurement of the heat capacities of salt hydrates for use as phase change materials 17
3.2 Method- and Material Development 18
3.2.1 Multi-energy CT investigation of historic mortars 18
3.2.2 The potential of dendrochemistry and dendroecology in pollution research 18
3.2.3 Development, verification and parameterization of a 3D swelling model for plant leaves 19
3.2.4 A Molecular Dynamic Study on Thermal and Mechanical Properties of Elastomers 20
3.2.5 Ion implantation of graphene oxide and polyimide by low and medium energy gold ions 21
3.2.6 Preparation and analysis of MXenes 22
3.3 Topic: Environmental Technology 23
3.3.1 Electrospun Nanofibrous Textiles for Carbon Dioxide Capture 23
3.3.2 Hydrogen Evolution on 2D MoS₂ Prepared by Liquid-Phase Exfoliation: Effects of pH Variations 23
3.3.3 Polymer Membranes for Various Applications 23
3.3.4 Development and characterization of gelatin/silica-nanofiber-based composites 24
3.3.5 Nanodiamond functionalized implant surfaces for the formation of a vital oral soft tissue composite 24
3.3.6 Solvothermal production of a piezoelectric layer on titanium implant materials 25
3.3.7 Hydrodynamic Optimization of Stem Cell Bioreactor with CFD Modeling and PIV experiments 29
3.3.8 The effect of primary and secondary flows on the homogenization process in a vertical bladed mixer 29Materiáloví vědci z Ústí nad Labem a Drážďan se v prosinci 2024 sešli na prvním materiálovém sympoziu v rámci projektu Interreg MATun se zaměřením na výrobní procesy, charakterizaci ma-teriálů, environmentální technologie a biotechnologie. Cílem sympozia bylo podpořit mezioboro-vou výměnu mezi českými a německými výzkumnými institucemi a podpořit nadnárodní spolupráci na mezinárodní úrovni podél sasko-české hranice.
Organizované aktivity se věnovaly jak vědeckým prezentacím aktuálních doktorských projektů a výzkumným tématům, tak i diskusím o možné spolupráci a společnému posezení u čaje s vánočním občerstvením. Konference byla financována z programu spolupráce INTERREG Česká republika – Sasko – 2021-2027. Všichni účastníci - doktorandi, vědečtí pracovníci a zaměstnanci zúčastněných institucí - využili příležitosti k navázání individuálních i nových kontaktů, k výměně názorů na ak-tuální výzkumná témata a metody, k nalezení východisek pro budoucí spolupráci mezi jednotlivými výzkumnými oblastmi a institucemi a také k diskusi o podobnostech a rozdílech mezi německou a českou výzkumnou krajinou.
Cílem sborníku z konference je představit jednotlivé instituce s jejich odbornými tématy a labo-ratořemi a prezentovat aktuální výzkumná témata vycházející z představených projektů.:Vorwort / Předmluva
1. Projekt MATun / Projekt MATun 2
1.1 Rückblick Symposium / Symposium - přehled 3
1.2 Organisationskomitee / Organizační výbor 3
2 Projektpartner und assoziierte Partner / Projektoví a přidružení partneři 4
2.1 Jan Evangelista Purkyně University in Ústí nad Labem 4
2.1.1 Naturwissenschaftliche Fakultät / Přírodovědecká fakulta 5
2.2 Technische Universität Dresden 11
2.2.1 Institut für Werkstoffwissenschaft / Ústav pro vědu o materiálech 11
2.3 TRANS³Net 14
3 Topics of the presentations 15
3.1 Manufacturing processes 15
3.1.1 Minimum water for maximum strength in semi-dry paper production 15
3.1.2 Horizontal Continuous Casting: optimization of process parameters for a better billet centre quality of high alloyed stainless steels at BGH Freital steel mill – Diploma Thesis 16
3.1.3 Mixing polydisperse granular materials with a focus on segregation 16
3.1.4 Surface Modification of Aluminium Samples Mimicking Scallop Shell Structures and Their Hydrophobic Properties 16
3.1.5 Heat exchange investigations for improved utility of working fluid mixtures in waste heat recovery applications 17
3.1.6 Calorimetric measurement of the heat capacities of salt hydrates for use as phase change materials 17
3.2 Method- and Material Development 18
3.2.1 Multi-energy CT investigation of historic mortars 18
3.2.2 The potential of dendrochemistry and dendroecology in pollution research 18
3.2.3 Development, verification and parameterization of a 3D swelling model for plant leaves 19
3.2.4 A Molecular Dynamic Study on Thermal and Mechanical Properties of Elastomers 20
3.2.5 Ion implantation of graphene oxide and polyimide by low and medium energy gold ions 21
3.2.6 Preparation and analysis of MXenes 22
3.3 Topic: Environmental Technology 23
3.3.1 Electrospun Nanofibrous Textiles for Carbon Dioxide Capture 23
3.3.2 Hydrogen Evolution on 2D MoS₂ Prepared by Liquid-Phase Exfoliation: Effects of pH Variations 23
3.3.3 Polymer Membranes for Various Applications 23
3.3.4 Development and characterization of gelatin/silica-nanofiber-based composites 24
3.3.5 Nanodiamond functionalized implant surfaces for the formation of a vital oral soft tissue composite 24
3.3.6 Solvothermal production of a piezoelectric layer on titanium implant materials 25
3.3.7 Hydrodynamic Optimization of Stem Cell Bioreactor with CFD Modeling and PIV experiments 29
3.3.8 The effect of primary and secondary flows on the homogenization process in a vertical bladed mixer 2