Development of a software system from existing components can surely have various benefits, but can also entail a series of problems. One type of problems is caused by a limited exchange of information between the developer and user of a component. A limited exchange and thereby a lack of information can have various consequences, among them the requirement to test a component prior to its integration into a software system. A lack of information cannot only make test prior to integration necessary, it can also complicate this tasks. This paper proposes a new strategy to testing components and making components testable. The basic idea of the strategy is to merge components and testing tools in order to make components capable of testing their own methods. Such components allow their thorough testing without disclosing detailed information, such as source code. This strategy thereby fulfills the needs of both the developer and user of a component.

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MicroRNAs are small noncoding RNAs that post-transcriptionally reduce protein output from most human mRNAs by mechanisms that are still obscure. This thesis provides insights into three aspects of microRNA biogenesis and function described below. MicroRNA precursors are excised from primary transcripts by the Microprocessor complex containing Drosha and DGCR8. Although most microRNAs are located in introns of protein-coding and noncoding genes, the mechanisms coordinating microprocessing and splicing are unclear. MiR-211 is a microRNA expressed from intron 6 of melastatin, a suspected melanoma tumor suppressor. We demonstrate that miR-211, and not melastatin, is responsible for the tumor suppressive function of this locus, that Drosha-mediated processing of the miR-211 precursor promotes splicing of melastatin exon 6-exon 7 junctions, and that perturbing 5' splice site recognition by the U1 snRNP reduces Drosha recruitment to intron 6 specifically and intronic microRNA levels globally. Thus we identify a novel physical and functional coupling between microprocessing and splicing. Typically, Agos stabilize mature microRNAs and as a complex stoichiometrically bind to complementary mRNAs. We demonstrate an alternative order of events in which Agos bind and repress pre-formed imperfect microRNA-mRNA duplexes in processing bodies of live cells, and cleave pre-formed perfect microRNA-mRNA duplexes in vitro. Our data support a novel catalytic model whereby Agos first deposit microRNAs onto mRNAs and dissociate, thus priming multiple microRNA-mRNA duplexes for concurrent repression by a single Ago. Despite key roles in development and pathogenesis, effectors and regulators of microRNA-mediated repression are still poorly characterized. An RNAi screen revealed that depletion of ribosomal proteins of either small or large ribosomal subunit dissociates microRNA-containing complexes from mRNAs repressed at translation initiation, increasing their polysome association, translation, and stability relative to untargeted mRNAs. Thus ribosomal proteins globally regulate microRNA function. Another RNAi screen revealed that Akt3 phosphorylates Ago2, which negatively regulates cleavage and positively regulates translational repression of microRNA-targeted mRNAs. Thus Ago2 phosphorylation is a molecular switch between its mRNA cleavage and translational repression activities. The following pages will place these novel insights into biological and disease-relevant context, will describe what was known prior to these studies, and will provide perspectives for future studies.

Galvanometer laser machining is a well-established laser machining technique in which the laser beam is positioned on a working field by means of mirrors mounted in galvanometers. Nonetheless, new applications make necessary the development of innovative techniques for increasing the performance of such systems. Aside all the advantages of this technique like given resolution, repeatability and velocity, a limited working area is an important drawback. In this thesis work, the limitations of different state-of-the-art schemes for increasing the working field of galvanometer laser machining systems are examined. The necessity of a new strategy for reducing present deviations introducing a vision system is established. The construction of an error vector and calculation of coordinate’s transformations to improve precision are presented. In this work, the “Arithmetic mean transformation”, “individual correction transformation”, “iterative inverse distance weighting transformation” and a stitching approach denominated “Auto-stitching” are presented and demonstrated as methods for reducing inherent deviations in galvanometer scanning systems for large area processing.

Galvanometer laser machining is a well-established laser machining technique in which the laser beam is positioned on a working field by means of mirrors mounted in galvanometers. Nonetheless, new applications make necessary the development of innovative techniques for increasing the performance of such systems. Aside all the advantages of this technique like given resolution, repeatability and velocity, a limited working area is an important drawback. In this thesis work, the limitations of different state-of-the-art schemes for increasing the working field of galvanometer laser machining systems are examined. The necessity of a new strategy for reducing present deviations introducing a vision system is established. The construction of an error vector and calculation of coordinate’s transformations to improve precision are presented. In this work, the “Arithmetic mean transformation”, “individual correction transformation”, “iterative inverse distance weighting transformation” and a stitching approach denominated “Auto-stitching” are presented and demonstrated as methods for reducing inherent deviations in galvanometer scanning systems for large area processing.

Biosensors are devices that detect biological elements and then transmit a readable signal. Biosensors can automatize diagnostics that would otherwise have to be performed by a physician or perhaps not be possible to perform at all. Current biosensors are however either limited to particular diseases or prohibitively expensive. In order to further the field, sensors capable of many parallel measurements at a lower cost need to be developed. Field effect transistor (FET) based sensors are possible candidates for delivering this, mainly by allowing miniaturization. Smaller sensors could be cheaper, and enable parallel measurements. Graphene is an interesting material to use as the channel of FET-sensors. The low electrochemical reactivity of its plane makes it possible to have graphene in direct contact with the sample liquid, which enhances the signal from impedance changes. Graphene-FET based impedance sensors should be able to sense almost all possible analytes and allow for scaling without losing sensitivity. In this work the steps needed to make graphene based biosensors are presented. An improved graphene transfer is described which by using low pressure to dry the graphene removes most contamination. A method to measure the contamination of graphene by surface enhanced Raman scattering is presented. Methods to produce double gated and electrolyte gated graphene transistors on a large scale in an entirely photolithographic process are detailed. The deposition of 1-pyrenebutyric acid (PBA) on graphene is studied. It is shown that at high surface concentrations the PBA stands up on graphene and forms a dense self-assembled monolayer. A new process of using Raman spectroscopy data to quantify adsorbents was developed in order to quantify the molecule adsorption. Biosensing has been performed in two different ways. Graphene FETs have been used to read the signal generated by a streaming potential setup. Using FETs in this context enables a more sensitive readout than what would be possible without them. Graphene FETs have been used to directly sense antibodies in high ionic strength. This sensing was done by measuring the impedance of the interface between the FET and the electrolyte.