- Cathepsin B (CTB) is a lysosomal cysteine protease with a plethora of physiological functions in protein turnover, remodelling of the extracellular matrix, hormone release and apoptosis. While CTB is confined to lysosomes in healthy tissues, malignant cells secrete CTB into the extracellular space, which is linked to cancer cell invasion, metastasis, angiogenesis, and chemotherapeutic resistance. High expression levels correlate with increased malignancy and metastasis, leading to poor prognosis. CTB therefore constitutes both a driver of malignant progression and an interesting prognostic cancer biomarker with potential for cancer imaging.
The focus of the research in our department is the functional characterization of tumour-associated proteins in vivo using positron emission tomography (PET). This imaging technique is based on appropriate molecules labelled with radionuclides, which are so called radiotracers. The radiotracers address the cancer-related targets and thus accumulate in the tumour and allow their spatially and temporally resolved monitoring through detection of the emitted positrons. The novel radiotracers as well as their non-radioactive analogues are characterised regarding their pharmacological properties in cells, organs and animal models.
For imaging CTB in cancer, one of our projects focuses on the development of radiotracers based on CTB-activatable cell penetrating peptides, which are basically molecular shuttles with selectivity for CTB-expressing cancer entities. The student’s project will contribute to the pharmacological optimisation of this imaging probe: The task will be synthesising an integrin ligand constituted by a small cyclic peptide that can be attached to the larger imaging probe. The laboratory work will cover a broad spectrum of techniques in organic chemistry, particularly solid-phase peptide synthesis and on-resin modification, analysis and purification by HPLC and product identification by mass spectrometry. The student will be integrated in a multidisciplinary team consisting of chemists, biologists and physicists with state of the art scientific equipment available to him.
- For the summer school project, histological evaluations of a human (HPV positive) tumour model using quantitative image analysis have to be done. Therefore, microenvironmental parameters such as pimonidazole hypoxic volume, relative vascular area and perfused fraction of vessels were determined for tumours which are unirradiated or after ten fractions with and without chemotherapy. Tumour sections have to be stained with pimonidazole and CD31 for hypoxia and vessels. After the staining process, slides have to be scanned by microscopy and analysed concerning their positive areas of the particular parameter. In the end, the results should be compared to the local tumour control data of these tumour model.
For this years’ summer student program we are seeking for a talented student that is interested in working closely with our group of physicists, computer scientists, and engineers. The student will mainly work on validation of a previously developed GATE model for our clinical PET/MR scanner located at the University Hospital Dresden. He/she will work with the latest version of GATE and thus will work with todays’ most advanced Monte Carlo simulation framework for PET systems. The main tasks of the student will be:
- Finalize the previously developed GATE simulation model of our clinical PET/MR system.
- Perform a systematic validation of simulation results in comparison to real PET phantom measurements and find further areas to improve the simulation.
- Optimize the current methods to convert output data of a simulation into input data for our iterative image reconstruction software.
All the above tasks will be performed in close collaboration with our team and includes some basic training on PET systems as well as on GATE so that the candidate will learn to work with it.
To fulfil these tasks it would be favourable if the candidate has some basic knowledge of tomographic imaging, the physics of PET or medical physics/imaging in general. In addition, adequate knowledge of numerical programming languages like R or MATLAB, functional programming skills using shell scripts and working in a Linux-oriented environment including extensive work on terminal/console environments would be favourable. The candidate must have strong abilities in abstract thinking as well as some basic knowledge in nuclear physics, should provide practical skills in using Unix/Linux-based systems and have to be able to suggest own solutions as well as being able to work on these with minor supervision.
- The student will design an electron energy spectrometer which will cover energy up to 2 GeV. He/She will use a particle tracer code (GPT) to simulate the beam propagating and determine an optimum geometry for best energy resolution. He/she will write an acquisition system based on python script
- HZDR offers a private GitLab installation to support the software engineering workflows of our scientists. The GitLab software package also includes components for continuous integration (CI) which can currently only execute software validation checks on dedicated servers. Since HZDR also develops a number of parallel simulations, we want to integrate our high performance computing (HPC) resources into GitLab by having the CI-engine start compute jobs (SLURM batch jobs) on the HPC clusters and return their output back to the CI-engine. The summer student is to develop a GitLab pluging for SLURM so that this is possible and that parallel tests can also be configured with GitLab. The developed component should be so well documented that we can push this component back to the GitLab developers for integration into future versions of GitLab.
The student will perform the study of magnetization dynamics in laterally patterned nanostructures with periodical modulation of magnetic properties (magnetic landscapes) using broad band ferromagnetic resonance technique. The tasks will include the literature review on 2D periodical magnetic patterns, mastering the experimental setup for performing the experiments and learning data analysis software. In addition, the student will measure the static magnetic properties using SQUID magnetometry as well as learn the magnetic imaging using magnetic force microscopy and/or Kerr microscopy.
Detection and Manipulation of Magnons in magnetic nanostructures. The project will involve electrical high frequency measurements based on spintronic effects and magneto-optics.
The research is in solid state physics and material sciences, in particular in the emerging field of antiferromagnetic spintronics.
The student will engage in the measurement of magnetic properties of samples of antiferromagnetic thin films based on the novel method of Zero-Offset Hall magnetometry.
At the beginning of the project, a decision for one of two main directions will be made in a dialog with the student to guarantee a project best suited to the interests of the student:
Subtopic 1: Precision measurements of magnetic properties in solid state matter
Precision measurements require sophisticated measurement sequences that may require days to weeks to yield significant results. Therefore, these investigations will be limited to few or even a single sample system. The student will learn about automation and programming of reproducible measurement sequences and should have a background in computer sciences. A substantial part of the work will deal with the automated and algorithmic analysis of large amounts of data. These measurements will generate unprecedented insight into magnetic phenomena in antiferromagnetic thin films as they are possible exclusively using Zero-Offset Hall at the Helmholtz-Zentrum Dresden-Rossendorf. Subtopic 2: Investigation of the dependence of a certain material property, e.g. composition, thickness, preparation conditions, on its magnetic behavior.
The possibility of using a lab-based electronic investigation method for the characterization of antiferromagnets brings a range of pressing material scientific question within the reach of experiments. One of these aspects will be selected at the beginning of the project and work will be dedicated to the preparation of a series of samples with engineered differences. While the magnetic properties of interest may be readily accessible using Zero-Offset Hall, the project may also include other structural investigation methods on site of the HZDR such as electron microscopy or x-ray diffraction.
Both projects orientations will include (i) sample preparatory work, (ii) electric measurements using an existing Zero-Offset Hall magnetometry setup, (iii) an analysis of the measurement results and (iv) preparation of a summary of the research work.
- The student will, depending on their skill set, conduct high performance compute simulations, analyse data from previous simulations or support the of understanding experimental data with the help of theoretical models and simulations. We also support applications in the area of computer science, specifically many-core programming, high performance computing and data science including machine learning.
The project will entail the investigation of spin-transport in either half-metallic spin-valve systems or in perpendicularly magnetised transition-metal wires. The effect of spin polarised currents on the current induced switching of magnetisation will be the main focus. The student will be able to fabricate his or her own individual samples as well as design and modify their experiment. The use of current to control the switching of magnetic elements is usefuly for novel magnetic memory elements, like STT-MRAM. In order to become real world devices the critical current for switching must be characterised and reduced to the lowest possbile value.
The student will have full access to the research group and all the associated process techniques, tools and resources. Each week the student will present his or her work and contribute to the group discussion.
- The nuclear astrophysics dealing with nuclear reactions which are building up the elements of the universe and powers the stars. These reactions has such a low cross section, that their investigation requires low background environment. In the Dresdner Frelsenkeller a new underground accelerator laboratory is being built which fulfils this criteria. The summer student shall test the ion source of the newly installed accelerator, determine the beam characteristics. Subsequently she/he will be involved in the first beam test of the whole accelerator assembly.
- The project will deal with radiation transport simulations using Monte Carlo techniques. These simulations are needed to optimize the particle transport in a new accelerator-based beamline and improve the understanding of experimental conditions. During the course of the program, the student will learn how to create a geometrical model of the corresponding experiment or facility, how to implement the primary radiation sources as well as the underlying physics processes, and how to extract, analyze and interpret the results from the simulation output.
- The summer student is intended to perform first measurements with our new Medium Ion Energy Scattering (MEIS) experiment. In particular spectra of samples that were characterized by other methods before have to be acquired and compared to the previous results. From these findings the summer student should derive device specific calibration parameters and find optimum operation conditions. Further the summer student will be involved in setting up a tool chain for semi-automated data analysis of the acquired spectra.
- Subtopic 1: Two-Dimensional Metal-Organic Framework: magnetic properties - Metal-organic frameworks (MOFs) are hybrid porous materials based on crystalline coordination polymers consisting of metal atoms or clusters connected by organic ligands. Their physical and chemical properties as well as pore size can be tuned by varying abundant organic ligands, metal centers and framework geometries. The materials will be prepared at TU-Dresden. Your task is to measure and understand the magnetic properties by using SQUID-VSM.
Subtopic 2: Magnetic properties of SiMn alloys - Non-stoichiometric SiMn alloys are reported to exhibit room temperature ferromagnetism and anomalous Hall effect. The slight excess of Mn and the resulted defects are proposed to be the origin of the exotic magnetic properties compared with the stoichiometric compound. We will use ion implantation to finely tune the stoichiometry of Si-Mn alloy films and to introduce defects as well. Your task is to investigate the magnetic, structural and transport properties of these alloys.
- - Optimization of the flash-lamp annealing conditions, which render the best material quality.
- Structural characterization of Si hyperdoped with chalcogens by Raman, RBS and PIXE.
- Optical characterization by Fourier transform IR (FTIR) spectroscopy
- Investigation of the electrical properties by Hall measurements at room and low-temperatures (to inspect the metal-insulator transition)
- Electro-optical characterization of the extended IR hyperdoped photodiodes.
- The summer student should analyse data from a recent experiment on the 22Ne(p, gamma)23Na reaction. This nuclear reaction is important for hydrogen burning in asymptotic giant branch stars and may affect in particular the final 22Ne and 23Na abundances. Several high-energy resonances in this reaction were studied in a radiative-capture experiment at the HZDR 3 MV Tandetron. The summer student should determine the strengths of these resonances using well-established techniques. The task involves computer-based analysis of gamma-ray spectra, mainly in the ROOT / C++ framework, and the physical interpretation of the data. Ideally also the thermonuclear reaction rate shall be determined.
- The internship will focus on laser wake field acceleration (LWFA) as a source of betatron x-rays for probing of matter and the development of the x-ray diagnostics both for x-ray scattering and absorption spectroscopy for experimental plasma physics with main focus on dense plasmas for laboratory astrophysics. The student will work mainly at the DRACO laser facility in HZDR. Participation in experiments at other facilities like the PALS laser in Prague or the PHELIX laser in GSI, Darmstadt is also possible during this placement. There will also be an opportunity to get involved in the development of x-ray and electron diagnostics and combining those with laser proton acceleration for multi-beam experiments. The project will be primarily experimental with an option to also work on computational simulations and theory.
- Cryogenic hydrogen jets are very interesting targets for laser driven proton acceleration as they can be operated at high repetition rates and since they are very small, only a few microns in diameter, side-view images of the laser plasma interaction can be generated using optical probing. For the latter we use a stand-alone laser system, which must be temporally synchronized to the main laser pulse within the precision of the laser pulse duration (about 100 fs). Here the task will be to develop and characterize an optical setup to measure the temporal overlap of the probe and the main laser pulse and to analyze the temporal jitter between the pulses.
- Nanowires are quasi-one-dimensional nanostructures with length-to-width aspect ratios typically greater than 10. Various high quality nanowires made of III-V semiconductors (like GaAs or InAlAs) are grown in our institute using molecular beam epitaxy. Potentially they can be used for building of extremely small ultrafast transistors for quantum computations. The main goal of your work will be to measure the mobility of electrons photoinjected in nanowires. The measurements will be performed in a contactless way using optical-pump terahertz-probe spectroscopy in order to observe the localized surface plasmon in nanowires.
- The main responsibility of a summer student will be to assist in the positron annihilation spectroscopy (PAS) measurements and data analysis of the above mentioned research topics with a primary subjects: (i) the role of defects in magnetic phase transitions in FeAl systems, (ii) kinetics of pore formation during curing processes in ultra low-k materials, and (iii) development of oxide memristor prototype for PAS investigations. PAS will be employed as a probe for defects evolution during material deposition and ion assisted deposition. Addition structural and magnetic characterization tools will be utilized for samples characterization, e.g., atomic and magnetic force microscopy, magneto-optical Kerr effect, vibrating sample magnetometry, scanning and transmission electron microscopy, X-ray diffraction, etc. A student will have a chance to participate in most of those investigations.
Subtopic 1: Improve the photoemission efficiency of magnesium photocathode - To improve the quality of photocathodes is one of the critical issues in enhancing the stability and reliability of the photoinjector systems, which defines the beam quality of the whole accelerator. The ELBE SRF Gun with Mg photocathodes has successfully provided 200pC/bunch CW electron beams for ELBE accelerator. Magnesium has a low work function (3.6 eV) and is relatively chemically stable. In our laboratory, you will have a chance to learn the cleaning process of Mg cathodes with a high intensity UV laser (activation). At the same time, alternative surface cleaning methods will be investigated. We sugguest to use excimer laser cleaning, ion beam sputtering and thermal treatment. The new cleaning procedures have to be tested and optimized, and the quantum efficiency (QE) of the photocathode samples has to be measured and analized statistically.
Subtopic 2: Possible MeV ultrafast-electron-diffraction (UED) based on ELBE SRF gun - High brightness, relativistic electron pulses with femtosecond duration are powerful tools for studying structural dynamic processes on atomic temporal and spatial scales in material, chemical, and biological sciences. In this work, we will use a beam dynamics simulation code "Astra" to study the Mega-electron-Volt (MeV) electron source based on ELBE SRF gun in order to probe the possility to generate the femtosecond beam required by the UED experiments.
Assessment of crystallographic orientation effects on Secondary Ion Mass Spectrometry (SIMS) analysis of natural sulfide minerals. Crystallographic orientation effects during SIMS analysis of some types of natural minerals are well documented. The physical processes which produce these effects are poorly understood. The crystallographic orientation of the sample relative to the incoming ion beam influences the total sputter yield, secondary ion counts and energies and consequently the inter-element and isotopic fractionation. For the natural minerals galena (PbS), sphalerite (ZnS), pyrite (FeS2) and pyrrhotite (Fe1-xS) systematic data are missing. In the framework of a SIMS study on the trace element content of the above mentioned minerals in a Pb-Zn ore deposit these information must be developed. The summer student will determine the crystallographic orientation of several mineral samples. Furthermore sputter experiments on these oriented samples using a CAMECA 7fauto instrument will be conducted. The resulting sputter holes will be analyzed by optical profilometry, SEM and AFM. Finally all results need to be analyzed, interpreted and presented in relation to the crystallographic orientation. A comparison of the experimental data with ion channeling calculations is necessary.