Reverse osmosis (RO) and nanofiltration (NF) membrane systems are high-pressure membrane filtration processes that can produce high quality drinking water. Biofouling, biofilm formation that exceeds a certain threshold, is a major problem in spiral wound RO and NF membrane systems resulting in a decline in membrane performance, produced water quality, and quantity. In practice, detection of biofouling is typically done indirectly through measurements of performance decline. Existing direct biofouling detection methods are mainly destructive, such as membrane autopsies, where biofilm samples can be contaminated, damaged and resulting in biofilm structural changes. The objective of this study was to test whether transparent luminescent planar oxygen sensing optodes, in combination with a simple imaging system, can be used for in-situ, non-destructive biofouling characterization. Aspects of the study were early detection of biofouling, biofilm spatial patterning in spacer filled channels, and the effect of feed cross-flow velocity, and feed flow temperature. Oxygen sensing optode imaging was found suitable for studying biofilm processes and gave detailed spatial and quantitative biofilm development information enabling better understanding of the biofouling development process. The outcome of this study attests the importance of in-situ, non-destructive imaging in acquiring detailed knowledge on biofilm development in membrane systems contributing to the development of effective biofouling control strategies.

abstract: Eosinophils are innate immune cells that are most commonly associated with parasite infection and allergic responses. Recent studies, though, have identified eosinophils as cells with diverse effector functions at baseline and in disease. Eosinophils in specific tissue immune environments are proposed to promote unique and specific effector functions, suggesting these cells have the capacity to differentiate into unique subtypes. The studies here focus on defining these subtypes using functional, molecular, and genetic analysis as well as using novel techniques to image these subtypes in situ. To characterized these subtypes, an in vitro cytokine induced type 1 (E1) and type 2 (E2) eosinophil model was developed that display features and functions of eosinophils found in vivo. For example, E1 eosinophils secrete type 1 mediators (e.g., IL-12, CXCL9 and CXCL10), express iNOS and express increased levels of the surface molecules PDL1 and MHC-I. Conversely, E2 eosinophils release type 2 mediators (e.g., IL4, IL13, CCL17, and CCL22), degranulate and express increased surface molecules CD11b, ST2 and Siglec-F. Completion of differential expression analysis of RNAseq on these subtypes revealed 500 and 655 unique genes were upregulated in E1 and E2 eosinophils, respectively. Functional enrichment studies showed interferon regulatory factor (IRF) transcription factors were uniquely regulated in both mouse and human E1 and E2 eosinophils. These subtypes are sensitive to their environment, modulating their IRF and cell surface expression when stimulated with opposing cytokines, suggesting plasticity. To identify and study these subtypes in situ, chromogenic and fluorescent eosinophil-specific immunostaining protocols were developed. Methods were created and optimized, here, to identify eosinophils by their granule proteins in formalin fixed mouse tissues. Yet, eosinophil-specific antibodies alone are not enough to identify and study the complex interactions eosinophil subtypes perform within a tissue. Therefore, as part of this thesis, a novel highly-multiplexed immunohistochemistry technique was developed utilizing cleavable linkers to address these concerns. This technique is capable of analyzing up to 22 markers within a single biopsy with single-cell resolution. With this approach, eosinophil subtypes can be studied in situ in routine patient biopsies. / Dissertation/Thesis / Doctoral Dissertation Biochemistry 2020

L’adhérence et le frottement existent dans de nombreux systèmes techniques ainsi que dans les systèmes naturels. Ces deux phénomènes ont une influence importante sur la durabilité et l’efficacité des dispositifs techniques. Une approche reconnue pour ajuster précisément ces caractéristiques - outre le fait de modifier les propriétés physico-chimiques - est la texturation des surfaces en contact. Les surfaces de feuilles de plantes sont souvent décorées avec des morphologies de surface diverses, et présentent ainsi des fonctionnalités de surface remarquables. Cette thèse visait à réaliser une étude systématique de la mécanique de l’adhérence et du frottement sur des surfaces micro-structurées, répliquées à partir de surfaces de feuilles végétales, en contact avec une sonde qui s’inspire de l’organe adhérent d’un insecte. Les morphologies de surface de trois feuilles végétales différentes ont été directement transférées sur un polymère viscoélastique. Pour ce faire, trois approches différentes de reproduction ont fait l’objet d’une étude approfondie. La microscopie électronique à balayage et la microscopie confocale à balayage laser ont été utilisées pour l'évaluation qualitative et quantitative de la qualité de reproduction. Concernant l’étude de la mécanique du contact, un nano-indenteur a été modifié, permettant d’enregistrer les images in situ des contacts réels. Des tests de pull-off ont été menés afin d’évaluer quantitativement l’effet de la pré-charge sur la force d’adhésion et pour comprendre les modes distincts de collage/décollement. Des essais de frottement ont été effectués afin d’examiner l’effet de la charge normale et de la vitesse de glissement sur la force de frottement. Les résultats ont été discutés en fonction de la topographie de chaque surface. / Adhesion and friction exist in many technical systems as well as in natural ones. Both phenomena have a profound influence on the durability and efficiency of technical systems. A well-recognised way to tune these characteristics - besides altering the physicochemical properties - is the texturing of the interacting surfaces. Inspiringly, plant leaf surfaces are often decorated with diverse surface morphologies, and so show remarkable functionalities. This thesis aimed to perform a systematic investigation of adhesion and friction mechanics on micro-structured surfaces replicated from plant leaves, in contact with a probe, which was inspired from an insect’s adhesive pad. Surface morphologies of three different plant leaves were directly transferred onto a viscoelastic polymer. For this, three different replication approaches were comprehensively explored. Scanning electron microscopy and confocal laser scanning microscopy were used for the qualitative and quantitative evaluation of replication ability. For the contact mechanics investigation, a high-resolution nanoindenter was modified, with incorporating a unique feature to record the in-situ real-contact images. Pull-off tests were carried out to quantitatively evaluate the effect of pre-load on adhesion force characteristics and to understand distinct attachment-detachment modes. Friction investigations were performed to examine the effect of normal load and sliding speed on the friction force. Results were discussed with regard to each surface’s topography.

This thesis is divided into three main sections that deal with optical and magnetic thin films properties and their measurements techniques. Principles of the spectroscopic reflectometry and measurements of optical properties are described in the first part. Results of imaging reflectometry are most important. This technique is based on in situ monitoring of optical properties of SiO2 thin films during etching over the area cca 10 × 13 mm2. In next section magnetic properties of thin films and new apparatus built on the Institute of Physical Engineering of BUT are shown. Magnetic properties were observed by longitudinal magneto-optical Kerr effect. The construction of the device is based on a light beam with rectilinear polarization reflected from magnetic material with turned polarization. For investigation of local magnetic properties of microstructures a microscope objective focusing laser beam on the sample is used. The last part of the thesis is aimed on improving of a spin valve structure Co/Cu/NiFe. This work was done within the frame of the Erasmus project in Laboratoire Louis Néel in Grenoble. The goal was to achieve the value of GMR (Giant Magnetoresistance) as high as possible by changing of deposition parameters. This value describes the rate of resistances in different mutual directions of magnetization in trilayers.