Retinoblastoma-binding protein 4 (RBBP4) is a subunit of chromatin remodeling factor 1 (CAF-1) and is essential for mammalian oocyte maturation, embryo survival, and embryo implantation. RBBP4 also localizes to the chromatin and is a ubiquitously expressed nuclear protein. Previous methods used to study this protein include short interfacing RNAs (siRNAs) and CRISPR/Cas9. These techniques have limitations such as determining an indirect depletion of proteins, may trigger compensatory mechanisms, and may not be useful in non-dividing primary cells. A new, acute, and rapid endogenous protein depletion technique called Trim-Away, can overcome these limitations. Trim-Away is also widely applicable since it can be used with many off-the-shelf reagents. Trim-Away utilizes the TRIM21-antibody interaction within the cytosol and the ubiquitin-proteasome pathway (UPP) to target and degrade a protein of interest. Studying RBBP4 using Trim-Away can offer insight into possible new functions of RBBP4 and its maternal effect, and increase the knowledge on a new, acute, and endogenous protein depletion technique. Here we report that, RBBP4 is required for proper blastocyst development and RBBP4 is more abundant in MII oocytes than GVBD oocytes. We also report that the loss of RBBP4 hinders RNA synthesis and causes cell death in later stages of embryo development. While our Trim-Away methodology can deplete RBBP4 as early as the 2-cell stage in embryos, our oocyte Trim-Away protocol needs to be optimized.

The subject of this diploma thesis is a design of rudder aerodynamic balance and its optimization with regard to control forces and vertical tail and fuselage loading in critical flight modes – critical engine failure.

Time of Flight - Elastic recoil detection analysis (ToF-ERDA) is a method used to analyse the composition of wall samples from fusion devices. All current analysing software for ToF-ERDA assumes that the target is perfectly flat which could create inaccuracies when rough surfaces are analysed. The aim of this project was to get a better understanding of how the roughness of samples from fusion devices affect the results from ToF-ERDA. To investigate this, three existing simulation softwares SIMNRA, TRIM and Potku were used. Programs were developed in order to use these to simulate three different targets with varying roughness, which were modelled as a combination of surfaces of different thicknesses. The results from which were put back into Potku where the differences between the targets could be noted. The study shows that it was possible to apply roughness to the already existing programs and showed similarities between the resulting depth profiles. When applying roughness, the concentration of surface elements decreased at the top of the layer but also went further into the sample. / Time of Flight - Elastic recoil detection analysis (ToF-ERDA) är en metod som används för att analysera kompositionen av prover av väggmaterial från fusionsreaktorer. Alla mjukvaror som används för att analysera datan från ToF-ERDA idag antar att provets yta är helt platt vilket skulle kunna innebära att felaktiga resultat erhålls när så ej är fallet. Målet med där här projektet var att undersöka och skapa en bättre förståelse för hur skrovligheten hos material från fusionsanordningar påverkar resultaten från ToF-ERDA. För att undersöka detta användes tre simulationsmjukvaror, SIMNRA, TRIM och Potku. Program skrevs för att använda dessa för att simulera tre olika material med olika stor skrovlighet, vilka modellerades som en kombination av material med olika tjockt ytskikt. Resultaten från dessa analyserades därefter i Potku där skillnaderna mellan materialen kunde noteras. Studien visar att det är möjligt att implementera ojämnhet i den simulationsprogram som finns idag och flera likheter mellan de resulterande djupprofilerna från de olika simulationsmetoderna uppmärksammades. När högre skrovlighet användes minskade koncentrationerna av ytelementen vid materialets topp men djupet som de når i materialet ökade. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

No description available.

Self-organization of regular surface pattern under ion beam erosion was described in detail by Navez in 1962. Several years later in 1986 Bradley and Harper (BH) published the first self-consistent theory on this phenomenon based on the competition of surface roughening described by Sigmund’s sputter theory and surface smoothing by Mullins-Herring diffusion. Many papers that followed BH theory introduced other processes responsible for the surface patterning e.g. viscous flow, redeposition, phase separation, preferential sputtering, etc. The present understanding is still not sufficient to specify the dominant driving forces responsible for self-organization. 3D atomistic simulations can improve the understanding by reproducing the pattern formation with the detailed microscopic description of the driving forces. 2D simulations published so far can contribute to this understanding only partially. A novel program package for 3D atomistic simulations called trider (TRansport of Ions in matter with DEfect Relaxation), which unifies full collision cascade simulation with atomistic relaxation processes, has been developed. The collision cascades are provided by simulations based on the Binary Collision Approximation, and the relaxation processes are simulated with the 3D lattice kinetic Monte-Carlo method. This allows, without any phenomenological model, a full 3D atomistic description on experimental spatiotemporal scales. Recently discussed new mechanisms of surface patterning like ballistic mass drift or the dependence of the local morphology on sputtering yield are inherently included in our atomistic approach. The atomistic 3D simulations do not depend so much on experimental assumptions like reported 2D simulations or continuum theories. The 3D computer experiments can even be considered as ’cleanest’ possible experiments for checking continuum theories. This work aims mainly at the methodology of a novel atomistic approach, showing that: (i) In general, sputtering is not the dominant driving force responsible for the ripple formation. Processes like bulk and surface defect kinetics dominate the surface morphology evolution. Only at grazing incidence the sputtering has been found to be a direct cause of the ripple formation. Bradley and Harper theory fails in explaining the ripple dynamics because it is based on the second-order-effect ‘sputtering’. However, taking into account the new mechanisms, a ‘Bradley-Harper equation’ with redefined parameters can be derived, which describes pattern formation satisfactorily. (ii) Kinetics of (bulk) defects has been revealed as the dominating driving force of pattern formation. Constantly created defects within the collision cascade, are responsible for local surface topography fluctuation and cause surface mass currents. The mass currents smooth the surface at normal and close to normal ion incidence angles, while ripples appear first at θ ≥ 40°. The evolution of bimetallic interfaces under ion irradiation is another application of trider described in this thesis. The collisional mixing is in competition with diffusion and phase separation. The irradiation with He+ ions is studied for two extreme cases of bimetals: (i) Irradiation of interfaces formed by immiscible elements, here Al and Pb. Ballistic interface mixing is accompanied by phase separation. Al and Pb nanoclusters show a self-ordering (banding) parallel to the interface. (ii) Irradiation of interfaces by intermetallics forming species, here Pt and Co. Well-ordered layers of phases of intermetallics appear in the sequence Pt/Pt3Co/PtCo/PtCo3/Co. The trider program package has been proven to be an appropriate technique providing a complete picture of mixing mechanisms.

No description available.

No description available.

In the past years solid state disks have developed drastically and are now gaining increased popularity compared to conventional hard drives. While hard disk drives work predictable, transparent SSD routines work in the background without the user’s knowledge. This work describes the changes to the everyday life for forensic specialists; a forensic investigation includes data recovery and the gathering of a digital image of each acquired memory that provides proof of integrity through a checksum. Due to the internal routines, which cannot be stopped, checksums are falsified. Therefore the images cannot prove integrity of evidence anymore. The report proves the inconsistence of checksums of SSD and shows the differences in data recovery through high recovery rates on hard disk drives while SSD drives scored no recovery or very poor rates.

Simulations play an integral role in the understanding and development of rotor- craft aeromechanics. Computational Fluid Dynamics coupled with Computational Structural Dynamics (CFD/CSD) offers an excellent approach to analyzing rotors. These methods have been traditionally “loosely-coupled” where data are exchanged periodically, motion is prescribed for CFD, and the updated loads have a static component for CSD. Loosely-coupled CFD/CSD assumes the solution to be periodic, which may not be true for some simulations. “Tightly-coupled” CFD/CSD, where loads and motion are exchanged at each time step, does not make this periodic assumption and opens up new avenues of simulation to research. A major drawback to tightly-coupled CFD/CSD is an increase in computational cost. Different approaches are explored to reduce this cost as well as examine numerical implications in solutions from tightly and loosely-coupled CFD/CSD. A trim methodology optimized for tightly-coupled simulations is developed and found to bring trim costs within parity of loosely-coupled CFD/CSD simulations. Aerodynamic loading is found to be nearly similar for fixed controls. However, the lead-lag blade motion is determined to contain a harmonic in the tightly-coupled analysis that is not an integer multiple of the rotor speed. A hybrid CFD/CSD methodology employing the use of a free-wake code to model the far-field effects of the rotor wake is developed to aid in computational cost reduction. Investigation of this approach reveals that computational costs may be reduced while preserving solution accuracy. This work’s contributions to the community include the development of a trim algorithm appropriate for use in tightly-coupled CFD/CSD simulations along with a detailed examination of the physics predicted by loose and tight coupling for quasi-steady level flight conditions. The influence of the wake in such cases is directly examined using a modular hybrid coupling to a free-wake code that is capable of reduced cost computations.

Accurate prediction of performance is an important aspect of modern sailing yacht design and provides a competitive advantage on the racecourse and in the marketplace. Although wind tunnel testing of yacht sails is a common tool for obtaining input data for Velocity Prediction Programs, its results have not been validated against aerodynamic full-scale measurements as quality full-scale data is rare. Wind tunnel measurements are conducted at the Twisted Flow Wind Tunnel of The University of Auckland and are compared to the full-scale aerodynamic force measurements from the Berlin Sail-Force-Dynamometer. To realise this comparison wind tunnel techniques and aerodynamic force models for yacht sails are enhanced; this in turn also improves the accuracy of Velocity Prediction Programs. Force and surface pressure measurements were conducted demonstrating that the interaction of the hull/deck with the sails has a significant effect on the side force and the force perpendicular to the deck plane, and that this should be considered in aerodynamic analysis of sails and the performance prediction of yachts. The first Real-Time Velocity Prediction Program for wind tunnel testing has been developed and implemented as an additional module of FRIENDSHIP-Equilibrium. Model sails can now be trimmed based on the full-scale performance of the yacht, and at the correct heel angle, which makes the trimming process in the wind tunnel much more similar to the real life situation. Improved aerodynamic force models have been developed from realistically depowered sail trims obtained with the Real-Time Velocity Prediction Program. An empirical model that describes the force and moment changes due to depowering in detail has been developed and implemented. The standard semi-empirical trim parameter model, which expresses depowering in a more generic way, has been enhanced based on aerodynamic principles and validated against the wind tunnel results. Utilising the enhanced wind tunnel techniques and aerodynamic force models, a generally good qualitative and quantitative agreement with the full-scale data is achieved. Remaining challenges associated with full-scale and wind tunnel tests are however also highlighted and, based on this work alone, a conclusive judgement that scaling effects are negligible cannot be made. / Whole document restricted, but available by request, use the feedback form to request access. / IPENZ Craven Scholarship; The University of Auckland Yacht Research Unit Scholarship; The University of Auckland Graduate Research Fund