Im Zusammenhang mit auf Reize reagierenden Materialien ist Licht aufgrund seiner hohen räumlichen und zeitlichen Auflösung von besonderer Bedeutung. Hierfür können molekulare Photoschalter, wie z.B. Azobenzole, in das Material eingebaut werden, um eine Reaktion auf Lichteinstrahlung von der molekularen auf die makroskopische Ebene zu übertragen. Fortschrittliche Moleküldesigns, wie z.B. Ortho-Fluorierung, führen dabei zu hervorragenden bistabilen Photoschaltern, die in Kombination mit Cyclodextrinen (CDs) als supramolekulare Bausteine eine Vielfalt an lichtempfindlichen Materialien ermöglichen. Um ein grundlegendes Verständnis der Wechselwirkungen von ortho-Fluorazobenzolen (FAzos) mit CDs zu erlangen, wurde in Kapitel II deren supramolekulare Wirt-Gast-Komplexierung untersucht. Hierbei konnte eine veränderte Barriere des Auffädelns der CDs beobachtet werden. Durch detaillierte Untersuchungen an polymeren Modellverbindungen in Kapitel III konnte gezeigt werden, dass das Auffädeln über die Z- im Vergleich zu den E-Isomeren der FAzos deutlich reduziert ist und dadurch die Bildung von Pseudo-Polyrotaxanen durch Bestrahlung mit Licht kontrolliert werden kann. Durch speziell konzipierte DOSY-Experimente konnte die Abfädelungskinetik aus Polyrotaxanen, bei denen die CDs durch das Z-Azobenzol auf der Achse fixiert wurden, verfolgt werden. Somit konnte gezeigt werden, dass eine Kontrolle der Bewegung von CDs durch Licht möglich ist. Auf Grundlage dieser Ergebnisse wurden in Kapitel IV neuartige lichtempfindliche Slide-Ring Materialien entwickelt, die bei Lichteinstrahlung eine reversible Änderung ihrer Steifigkeit aufweisen. Die Materialien wurden so konzipiert, dass sie ortho-Fluorazobenzole enthalten, die als durch Licht schaltbare Barrieren für das Gleiten von CDs entlang des Polymerrückgrats dienen. Hierdurch konnte eine reversible Änderung des Elastizitätsmoduls durch Bestrahlung mit Licht erzielt werden und somit ein erfolgreicher Konzeptnachweis erbracht werden. / In the context of stimuli-responsive materials, light is of particular importance due to its high spatial and temporal resolution. For this purpose, molecular photoswitches, such as azobenzenes, can be incorporated into the material to transfer a response to light irradiation from the molecular to the macroscopic level. Advanced molecular designs, such as ortho-fluorination, lead to excellent bistable photoswitches which, in combination with cyclodextrins (CDs) as supramolecular building blocks, enable a variety of light-responsive materials. To gain a fundamental understanding of the interactions of ortho-fluoroazobenzenes (FAzos) with CDs, their supramolecular host-guest complexation was investigated in Chapter II. An altered barrier for the threading of CDs was thereby observed. Detailed studies on polymeric model compounds in Chapter III showed that threading over the Z-isomers of the FAzos is significantly reduced compared to the E-isomers and that the formation of pseudo-polyrotaxanes can thus be controlled by irradiation with light. Using specially designed DOSY experiments, the threading kinetics from polyrotaxanes, in which the CDs where fixed on the axis by the Z-azobenzene, could be followed. This showed that it is possible to control the movement of CDs by light. Based on these results, novel photoresponsive slide-ring materials were developed in Chapter IV, which exhibit a reversible change in stiffness when exposed to light. The materials were designed to contain ortho-fluoroazobenzenes, which serve as photoswitchable barriers for the sliding of CDs along the polymer backbone. This enabled a reversible change of the elastic modulus to be accomplished by irradiation with light, thus providing a successful proof of concept.

Photoschalter sind Moleküle, die eine reversible lichtgesteuerte Umwandlung zwischen zwei Zuständen mit unterschiedlichen Eigenschaften durchlaufen. In den letzten zehn Jahren hat der Einbau dieser photochromen Moleküle in intelligente, auf Stimuli ansprechende Materialien zunehmende Aufmerksamkeit erregt, da sie die einzigartige Fähigkeit bieten, makroskopische Eigenschaften mit einem externen optischen Stimulus reversibel zu verstärken und zu verändern. Die begrenzte Leistung von Photoschaltern in festen Medien bleibt eine Herausforderung. In diesem Zusammenhang werden in dieser Arbeit zwei wichtige Aspekte näher untersucht. Erstens der Prozess der Entwicklung neuer Photoschalter mit maßgeschneiderten Eigenschaften und zweitens die Implementierung von Photoschaltern in feste Materialien und die damit verbundenen Herausforderungen. Im ersten Teil dieser Arbeit wurde Dynamisch-kovalente Chemie (DCC) verwendet, um die Entdeckung und Entwicklung einer neuartigen Klasse von Photoschaltern mit drei Zuständen zu beschleunigen. Die dynamische Natur der zentralen Doppelbindung von α-Cyanodiarylethenen wurde genutzt, um ein thermodynamisches Gleichgewicht mit anderen Arylacetonitrilen herzustellen. Die entwickelte Methode kombiniert eine schnelle Diversifizierung mit einer Rasterung auf spezifische Eigenschaften, die durch einen externen Stimulus aufgedeckt werden, und ermöglicht die effiziente Untersuchung der Beziehung zwischen Struktur und den zugehörigen Eigenschaften. Im zweiten Teil der Arbeit wird die Entwicklung und die Synthese eines Zweikomponenten-Kern-Schale-MOFs mit einem internen nicht-funktionalisierten Kompartiment, das von einer dünnen photoschaltbaren Außenschale bedeckt ist, vorgestellt. Diese Strategie ermöglicht ein effizientes Schalten des Chromophors und die resultierende dünne „intelligente“ Schale fungiert als modulare kinetische Barriere für die molekulare Gastdiffusion in das Material, die durch Licht gesteuert werden kann. / Photoswitches are molecules that undergo a reversible light-triggered conversion between two states with different properties. In the past decade, the incorporation of these photochromic molecules in smart stimuli-responsive materials has gained increased attention as it offers the unique ability to reversibly amplify and change macroscopic properties with an external optical stimulus. The limited performance of photoswitches in solid mediums remains a challenge. In this context two important aspects are studied in more detail in this thesis. First, the process of developing new photoswitches with tailored properties and second, the implementation of photoswitches in solid materials and the challenges associated with it. In the first part of this thesis dynamic covalent chemistry (DCC) was used to accelerate the discovery and development of a novel three-state photoswitch class. The dynamic nature of the central double bond of α-cyanodiarylethenes was exploited to establish a thermodynamic equilibrium with other arylacetonitriles. The developed DCC tool combines fast and efficient diversification with screening for specific photochemical properties revealed by an external stimulus, enabling the rapid study of the relationship between structure and the associated properties. The second part of this thesis summarizes the design and synthesis of a two-component core-shell MOF with an internal non-functionalized compartment covered by a thin photoswitchable outer shell. This strategy allows efficient switching of the chromophore and the resulting thin “smart” shell acts as a modular kinetic barrier for molecular guest diffusion into the material that can be controlled by light.

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Mechanical stimulation plays a crucial role in promoting cell differentiation. However, applying physical force directly to cells requires complex equipment and a sterile environment, posing challenges. To overcome this, stimuli-responsive biomaterials or 4D scaffolds can serve as an alternative platform for mechanical stimulation. These scaffolds, fabricated using advanced 3D printing techniques, can apply the necessary force to cells. To optimize their functionality, bioactive molecules or extracellular matrices can be incorporated or decorated on their surfaces. This thesis proposal focuses on developing a versatile material platform that allows customization through systematic composition adjustment and on-demand printing, while also offering surface modification capabilities. The primary objective is to create a novel cell carrier platform using thermo-responsive polymers. By manipulating the additive monomer compositions, we can finely adjust properties such as the transition temperature of the polymers, tailoring them to specific requirements. Furthermore, this platform will enable the fabrication of complex three-dimensional biomaterial structures with controllable porosity, a critical aspect of biomaterial design. Leveraging the capabilities of three-dimensional printing technology, we can program and achieve desired porosity levels in the printed structures, providing enhanced flexibility for biomaterial design. The development of thermo-responsive scaffolds involved three distinct stages aimed at designing an optimized platform that effectively operates within the physiological range while ensuring cell viability. One of the key challenges was to achieve a balance between thermoresponsive behavior and biocompatibility. In the initial stage, we investigated the interplay between a crosslinkable three-armed macromer (trimethylolpropane triacrylate-TMPTA) and various monomers (N-isopropylacrylamide-NiPAAm, methyl methacrylate-MMA, dimethylaminoethyl acrylate-DMAEA, 4-acryloylmorpholine-AMO) using thermally induced solution polymerization. NiPAAm, known for its thermoresponsive properties, was selected despite its limited biocompatibility. DMAEA was chosen to adjust the polymer network transition temperature by introducing cationic charge, which disrupts the coil-globule effect of PNiPAAm and provides cell adhesiveness of the composition. Additionally, the hydrophilic monomer AMO was incorporated to further fine-tune the polymeric network. We examined the behavior of these components within the physiological range and their integration into the PNiPAAm network, establishing significant correlations between the transition temperature of the polymer and the crosslinker and monomers in their soluble condition. In the second stage of our research, we introduced photo-induced polymerization to enhance the crosslinking ratio. By utilizing this method, we successfully fabricated photo-polymerized mixtures (photoresists) into thermo-responsive discs, enabling us to study their swelling behavior between 37℃ and 25℃. Our findings revealed that the swelling behavior could be adjusted by varying the ratios of the crosslinker and monomers in the experimental groups. Through careful experimentation, we identified a suitable composition (3% w/w TMPTA, 80% w/w NiPAAm, 15% w/w DMAEA, 5% w/w AMO, and 4% w/w photo-initiator(PI)) that required minimal crosslinking incorporation while still retaining thermo-responsiveness. Furthermore, we conducted a preliminary biocompatibility study by fabricating the mixture into thin-films and cultivating them with L929 fibroblast cells. In the third and final stage, we utilized the optimized formulations from the previous stage to build thermo-responsive 3D scaffolds using continuous Digital Light Processing (cDLP) printing. We investigated the effects of various parameters, such as curing time and monomer composition, on the swelling property of the scaffolds. Additionally, we introduced glycofurol (GF) as a photo-polymerization solvent, which allowed us to produce scaffolds with improved resolution and reduced printing time. The resulting optimized scaffolds, with a composition of 3% w/w TMPTA, 80% w/w NiPAAm, 15% w/w DMAEA, 5% w/w AMO, 4% w/w PI, and 10 seconds per layer, exhibited the desired thermo-responsiveness. To further understand the mechanical properties and thermal dependencies of these scaffolds, we conducted rheological analysis. This analysis helped establish a relationship between the mechanical properties of the scaffolds and their response to temperature changes. To investigate the potential of cell stimulation through periodic changes, we conducted an experiment involving the seeding of L929 fibroblasts and C2C12 myoblasts on thermo-responsive 3D scaffolds. Our objective was to assess the ability of cells to proliferate on scaffolds with different compositions. Specifically, we examined two types of scaffolds: lattice scaffolds, characterized by a porous structure with a periodic network that enables cells to inhabit a 3D environment, and raft scaffolds, which feature a dense 3D structure designed for cells to reside on the surface for observation and evaluation. The lattice scaffolds were composed of ≥2% w/w DMAEA, while the raft scaffolds consisted of ≥5% w/w DMAEA. To evaluate cell proliferation, we conducted direct contact experiments and employed live/dead assays, subjecting the scaffolds to temperature switching conditions at 31℃ and 37℃. These experimental setups aimed to provide insights into the response and behavior of cells in the presence of thermo-responsive scaffolds with varying compositions. The results revealed favorable adhesion and spreading of the cells on the scaffolds. Interestingly, in our dynamic temperature experiment, we observed that myoblasts seeded on the scaffolds exhibited both proliferation and spreading, whereas myoblasts subjected to constant-temperature conditions did not show the same behavior. This suggests that the expansion and contraction of the scaffold, observed in previous experiments, may impact cell viability. Further investigation is needed to better understand this phenomenon. Additionally, we enhanced cell adhesiveness of the scaffolds by impregnating the scaffolds with poly-L-lysine and tested them with hASCs (human adipose-derived stem cells). Significant differences were observed between scaffolds with and without poly-L-lysine, highlighting the effectiveness of this approach. In conclusion, we have successfully developed a thermo-responsive 3D scaffold that exhibits a transition temperature within the physiological range, ensuring cell survival, and provides mechanical stimulation to the cells through the coil-globule effect without causing cell detachment. Among the formulations tested, the GF-printed formulation (3% w/w TMPTA, 80% w/w NiPAAm, 15% w/w DMAEA, 5% w/w AMO, and 4% w/w photo-initiator) with an exposure time of 10 seconds per layer showed the most promising results for cell cultivation under periodic changes in temperature, with a transition temperature of 36.3 °C ± 0.9 °C. Furthermore, we conducted direct cell contact experiments and confirmed the biocompatibility of the thermo-responsive macromer-based scaffolds. These findings demonstrate that this material platform offers a versatile and responsive material for mechanical stimulation of cells on three-dimensional scaffolds. These promising results suggest that this approach holds significant potential for tissue engineering applications and can be utilized to develop mechanical stimulation devices for various biomedical applications.:CHAPTER 1……………………..……………...…………………………..…4 Introduction CHAPTER 2……………………..…………………………..……………….29 Material and Methods CHAPTER 3……………………………………..…..……………………….52 Thermo-Responsive Polymer from Thermal Synthesis Studies CHAPTER 4…………………………………..……………………………...70 An Adjustable Thermo-Responsive Polymer from Photo Synthesis CHAPTER 5……………………………………………………………....….88 Fabrication of Thermo-Responsive Scaffolds from DLP Printing CHAPTER 6…………………...…………………………………………....107 3D Scaffold Biocompatibility Studies CHAPTER 7…………………...……………………………………………139 Discussions CHAPTER 8…………………...……………………………………………161 Summery APPENDIX…………………...………………………………………….…166 Bibliography, List of Publications, CV, Declaration of Authorship, Acknowledgements, Related publication

This study used mixed methods to examine middle school mathematics teachers’ beliefs about English Learners’ ability to participate in rigorous, grade-level math instruction as well as beliefs about their own capacity for teaching English Learners. Additionally, the study investigated the influence of teachers’ beliefs on their instructional practices and identified the types of support teachers need to develop as culturally and linguistically responsive educators. Findings revealed some dissonance between teachers’ explicit beliefs about teaching English Learners and their implicit beliefs illustrated through instructional decisions made, as well as previously unrecognized gaps in teachers’ ability to identify and differentiate the needs of different types of English learners. Finally, the study identified teachers’ pressing needs for additional support at the school and district levels to continue to develop skills and knowledge to improve their teaching for English learners. The study concluded with an action plan for developing a robust professional learning system to develop teachers’ self-efficacy as culturally and linguistically responsive educators while also addressing implicit bias through reflection.

Recent developments in the area of Cyber-Physical Production Systems prove that high technology readiness level is already achieved and industrialization of such technologies is not far from today. Although these technologies seem to be convenient in providing solutions to environmental uncertainties, their application provides adaptability only at shop floor level. Needless to say, an enterprise cannot reach true adaptability without ensuring adaptation skills at every level in its hierarchy. Commonly used production planning and control approaches in industry today inherit from planning solutions which are developed in response to historical market characteristics. However, market tendency in recent years is towards making personalized products a norm. The emerging complexity out of this trend obliges planning systems to a transition from non-recurring, static planning into continuous re-planning and re-configuration of systems. Therefore, there is a need of responsive planning solutions which are integrated to highly adaptable production system characteristics. In this dissertation, Demand Responsive Planning, DRP, is presented which is a planning framework aiming to respond to planning needs of shifting trends in both production system technologies and market conditions. The DRP is based on three main constructs such as dynamicity, responsiveness and use of precise data. These features set up the foundation of accomplishing a high degree of adaptability in planning activities. By this means, problems from an extensive scope can be handled with a responsive behavior (i.e. frequent re-planning) by the use of precise data. The use of precise data implies to execute planning activities subject to actual demand information and real-time shop floor data. Within the context of the DRP, both a continuous workload control method and a dynamic capacity adjustment approach are developed. A test-bed is coded in order to simulate proposed method based on a system emulation reflecting the characteristics of cyber-physical production systems at shop floor level. Continuous Precise Workload Control, CPWLC, method is a novel approach aiming at precise control of workload levels with the use of direct load graphs. Supported by a multi-agent platform, it generates dynamic non-periodic release decisions exploiting real time shop floor information. As a result, improved shop floor performances are achieved through controlling workload levels precisely by the release of appropriate job types at the right time. Presented dynamic capacity adjustment approach utilizes rapid re-configuration capability of cyber-physical systems in achieving more frequent capacity adjustments. Its implementation architecture is integrated to the CPWLC structure. By this means, a holistic approach is realized whereby improved due date performance is accomplished with minimized shop floor congestion. Hence, sensitivity to changing demand patterns and urgent job completions is improved. / <p>QC 20150907</p>

Master of Science / Department of Architecture / R. Todd Gabbard / This research aims to explore and assess passive solar design techniques that promote high thermal comfort in vernacular houses of the state of Jharkhand in India. The study of these houses provides useful insights for designing energy efficient houses that provide thermally comfortable conditions. An analysis of these houses in Ranchi, the capital city of Jharkhand, India provides a context for the field research. Jharkhand predominantly has two different styles of vernacular houses: huts and havelis. These houses were constructed, without any mechanical means, in such a manner as to create micro-climates inside them to provide high thermal comfort levels. Hence the study of thermal comfort levels in these buildings in relation to built environment in today's context is significant. As part of data collection, interviews were conducted with the occupants of ten houses in Ranchi, in June 2007. Two houses of each (huts and havelis) were selected for detailed experimental analysis. Experiment results indicated that all the four selected houses exhibited lower ambient temperature than outside during the day and a higher ambient temperature at night. Brick bat coba and lime mortar were the key materials used for constructing high thermal-mass walls. Adequate ventilation is significant in creating conditions that are comfortable. Aperture to volume ratio of less than 0.051 is not adequate enough to cool the thermal mass of these houses. These houses also use attic space to mitigate the heat gain from the roof. Courtyards and other exterior spaces form an integral part of these houses and influence the thermal conditions in and around the houses. The case studies show that there is a scope for more relaxation of comfort temperature range based on culture and phenomenon of acclimatization. A universal approach in understanding and defining comfort condition fails because the users of these houses were comfortable in conditions defined as uncomfortable by ASHRAE and Nicol.