GUPEA

Gothenburg University Publications Electronic Archive

GUPEA is a platform for e-publishing of theses, student essays and other research publications.

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Recent Submissions

  • In-Vehicle Radar Based Heart Rate Monitoring
    (2026-01-20) Xiaotian Zhang; José Eduardo Maciel Mendoza; University of Gothenburg/Department of Physics; Göteborgs universitet / Institutionen för fysik
    Interior radar has recently emerged as a promising technology in non-contact vital sign (NCVS) sensing. This thesis discusses the underlying principles and techniques of radar-based heart rate detection, focusing on the measurement of subtle movements of the chest wall associated with cardiac activity. By applying carefully designed filters and analyzing the radar signals, we can monitor the heart rate of high sensitivity in the time domain. After the experiment, the radar was placed in a suitable position in the car to collect clear signals, and then processed the signal filters with minimum phase shift, and smoothed the signal using a Gaussian filter, finally obtained promising heartbeat signals within proper thresholds and parameters setting. The obtained radar heart rate signals matched the heart rate of the ones simultaneously acquired from the pulse sensor with an accuracy of up 96%. Our thesis has laid down the groundwork for exploring new measures for health indications in the future.
  • A Unified Software-Generating Framework for Biological Data Analysis
    (2026-01-20) Chang, Yu-Wei
    In recent decades, biological data analysis has increasingly relied on software. For example, complex analyses of the human brain or plant data have often been conducted with newly developed toolboxes, workflow engines, and graphical platforms. As the software ecosystem grows, however, it becomes harder to keep code, interfaces, and tests in step, and to reuse methods across studies, modalities, and domains without rewriting large parts of the stack. This thesis proposes a software-generating framework Genesis, which is implemented within an in-house-developed software ecosystem BRAPH 2 (BRain Analysis using graPH theory, second edition). The framework has two stages. First, each analysis component is written once as a human-readable .gen.m description that combines MATLAB code with structured declarations of its inputs, parameters, documentation, and a graphical interface. Second, a compiler turns these descriptions into executable modules, graphical interfaces, unit tests, and complete, shareable software distributions. The core idea of Genesis is to shift effort from crafting one-off tools and graphical user interfaces to maintaining a centrally defined library of descriptions. Most importantly, these centrally defined descriptions can be recombined and regenerated to investigate a different research question, while the code, interfaces, and tests remain in sync. This thesis presents four studies to demonstrate Genesis’s feasibility across different biological analyses. BRAPH 2, a distribution for network neuroscience, provides the initial infrastructure for graphical interfaces, pipeline orchestration, and core statistical and neural-network elements. Using the same .gen.m description language and compiler, GapNet extends this stack with an alternative training approach for incomplete neuroimaging cohorts. The human bone-marrow light sheet microscopy study adds graph-based microenvironment descriptors and variational autoencoder elements for unsupervised niche discovery. Finally, the plant Raman spectroscopy study reuses the same autoencoder machinery, with minimal spectral preprocessing, to characterise stress responses across species and stressors. Taken together, these studies show that a single description-centred framework can span imaging and spectroscopy, minimise boilerplate, and make complex pipelines more portable, auditable, and extensible. By treating code, interfaces, and tests as generated views of shared .gen.m descriptions, Genesis supports more transparent and reproducible development of analysis software in computational biology.
  • Ur vår äldsta bok : [Äldre västgötalagen] /
    (1912) Beckman, Natanael,
  • Quantitative Optical Microscopy of Microscale Soft Matter Systems
    (2026-01-19) García Rodríguez, Berenice
    Biological and soft-matter systems contain a wide variety of nano- and microscale particles whose physical properties, such as size, internal organization, and refractive-index contrast as a proxy for internal concentration, influence their function. Yet, most of these structures are weakly scattering and lie below the diffraction limit, making them difficult to access with conventional optical microscopy. Many existing characterization techniques rely on ensemble averaging or diffusion-based sizing, masking particle-level heterogeneity, and limiting quantitative insight into nanoscale biology and soft condensed matter. These challenges are particularly crucial for biomolecular condensates, whose submicrometer sizes, low refractive-index contrast, and dynamic internal structure place them outside the reach of standard imaging and scattering approaches. This thesis presents two complementary interferometric methods for label-free, single-particle characterization across the nano–microscale. The first, Dual-Angle Interferometric Scattering Microscopy (DAISY), combines forward- and backward-scattered light with single-particle tracking to extract optical size, polarizability, refractive-index contrast, and hydrodynamic mobility for individual nanoparticles. This dual-channel design enables media-independent sizing and morphological inference by comparing optical size with mobility-based measurements. The second method integrates off-axis holographic microscopy with quantitative scattering analysis to characterize thousands of weakly scattering biomolecular condensates at the submicrometer scale. By reconstructing the full complex optical field and fitting appropriate scattering models, this approach retrieves condensate size, refractive index, internal mass distribution, interfacial structure, and hydrodynamic mobility. Applied to condensates formed by proteins, the method reveals salt-dependent structural changes, distinct interfacial morphologies, and dynamic behavior inaccessible to ensemble or diffusion-based techniques. Together, these developments establish a unified, label-free framework for probing the structure and dynamics of nanoparticles and biomolecular condensates at the single-particle level. By bridging optical and mechanical observables, this work expands the range of soft-matter systems that can be quantitatively characterized and provides new tools for exploring the physical principles underlying phase-separated biological assemblies.
  • Instrument Development for Laser Spectroscopy of Gas-Phase Molecules
    (2026-01-19) Mulham Al Hashemi; University of Gothenburg/Department of Physics; Göteborgs universitet / Institutionen för fysik
    In this thesis, a laser-based spectroscopic instrument combining resonance-enhanced multiphoton ionisation (REMPI) with time-of-flight mass spectrometry (TOF-MS) is developed, optimised, and applied to the study of gas-phase molecules. The system enables the generation of cold molecular beams under high-vacuum conditions, provides tunable ultraviolet (UV) radiation for resonant excitation, and allows massresolved detection of photoions with high sensitivity and selectivity. The performance of the REMPI–TOF setup is first tested using toluene as a benchmark molecule. TOF and mass spectra are used to verify mass calibration and resolution, while wavelength-resolved REMPI measurements demonstrate selective excitation of electronic and vibronic transitions under conditions of strong rotational and vibrational cooling, corresponding to molecular temperatures of only a few kelvin. The study is subsequently extended to the chiral aromatic alcohol (R)-1-phenylethanol. Due to its low vapour pressure at room temperature, an internally heated oven is employed to ensure stable sample introduction into the molecular beam. Mass-selected REMPI spectra recorded with different carrier gases reveal how the expansion conditions influence signal intensity, stability, and clustering behaviour. Finally, REMPI spectroscopy is applied to weakly bound molecular complexes, including toluene dimers and chiral complexes formed between (R)-1-phenylethanol and chiral alcohols. In addition, a high-vacuum source chamber was designed, constructed, and characterised at the University of Gothenburg, and subsequently integrated into an experimental setup at the University of Hamburg, where it enables flexible molecular-beam generation for future spectroscopic studies. Overall, this work demonstrates that the developed REMPI–TOF mass spectrometer provides a versatile and sensitive instrument for high-resolution, mass-resolved spectroscopy of isolated molecules and weakly bound molecular complexes in the gas phase.