We hypothesized that alterations in cardiac myofilaments are associated with hereditary canine DCM. DCM myofilaments demonstrated a reduction in EC50 and a modest decrease in maximum activity compared to non-failing dog samples. Treatment of myofilaments with the calcium sensitizer, bepridil, showed a reduction in EC50. Desmin and tropomyosin phosphorylation was increased in DCM. Desmin protein levels were increased in DCM. Total troponin I phosphorylation was unchanged, but S23/S24 phosphorylation was reduced in DCM. Myofilament-associated PKC-δ and -ζ were elevated in DCM, PKC- ε was modestly reduced, and PKC-α showed no change. These data are the first investigation of cardiac myofilaments in naturally occurring canine DCM, and support the hypothesis that alterations in cardiac myofilaments are associated with DCM. / OVC Pet Trust (operating funds)

Photodynamic therapy has been established as one of the approaches for the treatment of various malignant tumors. While most of the reagents used for this purpose are porphyrin derivatives, there is a strong motivation for finding novel and better sensitizers. Perylenediimides are known for their photo- and chemical stability, but they do not have absorptions in the red end of the visible spectrum. However, recently reported green perylenediimides which have dialkylamino substituents on the perylene core, provide an alternative. To that end, we have designed and synthesized novel green perylenediimides with remarkable water solubility at neutral pH and absorption peaks beyond 650 nm. We demonstrated that on red-light excitation, singlet oxygen trap 1,3-diphenyl-iso-benzofuran is rapidly degraded. We also carried out cell culture experiments / an important parameter to be optimized for practical application as a novel photodynamic therapy agent was the excited dye toxicity to dark toxicity. Our results confirmed that these novel perylenediimides acted as sensitizers generating singlet oxygen and the initial in vitro biological experiments demonstrated their potential utility in photodynamic therapy.

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / O estudo envolvendo o desenvolvimento de cÃlulas solares fotovoltaicas tem sido um tema bastante comentado nos Ãltimos anos. A conversÃo de energia solar em energia elÃtrica, com a utilizaÃÃo de cÃlulas solares fotovoltaicas, tem sido realizada em grande parte atravÃs de dispositivos de junÃÃo semicondutora. PorÃm, vem ocorrendo algumas modificaÃÃes quanto ao uso dos materiais para o desenvolvimento destas cÃlulas, dentre essas mudanÃas pode se destacar o uso de corantes fotoexcitÃveis ou sensibilizadores. Neste trabalho utilizou-se a mesoporfirina, obtida a partir do LÃquido da Casca da Castanha de Caju, como sensibilizador de uma cÃlula solar fotoeletroquimica. Inicialmente uma lÃmina de vidro para microscopia recebeu a aplicaÃÃo de um filme fino de SnO2:F atravÃs da tÃcnica de spray pirÃlise, passando a apresentar propriedades condutoras. ApÃs isso, uma camada de TiO2:Ag foi aplicada sobre o vidro condutor para servir como suporte durante a imersÃo em soluÃÃo de mesoporfirina. ApÃs a adsorÃÃo do corante pela camada de TiO2:Ag, adicionou-se o eletrÃlito (I-/I3 -) e, por fim, a cÃlula foi fechada utilizando como contra eletrodo, um vidro condutor contendo uma camada de carbono em sua superfÃcie. As diferentes amostras de vidros condutores apresentaram resistÃncia elÃtrica de 3,77 â 8,00 Ω/□ e transmitÃncia em torno de 60% para comprimentos de onda de λ ≥ 600nm. A camada de TiO2:Ag aplicada apresentou uma espessura de cerca de 30 μm. Com a exposiÃÃo à luz solar foi verificado que ocorre na cÃlula uma corrente elÃtrica de 60,5 μA e tensÃo de 20,7mV / The study involving the development of photovoltaic solar cells has been a much commented subject on the past few years. The conversion of solar energy into electrical energy, with use of photovoltaic solar cells, has been done mostly through the use of semi conductive junction devices. But there have been some modifications about the materials used for the development of these cells; amongst these changes we can highlight the use of photo excitable dyes or sensitizers. In this work was used mesoporfirin, obtained from the liquid of the cashew nut, as the sensitizer in a photoelectrochemic solar cell. Initially, a glass used in microscopy received the application of a SnO2:F thin film through spray pyrolysis technique, thus presenting conductive properties. After that, a layer of TiO2:Ag was applied over the conductive glass to act as a support during the immersion in mesoporfirin solution. After thee adsorption of the dye by the TiO2:Ag layer, an electrolyte (I-/I3 -) was added and, in the end, the cell was closed using as counter electrode, a conductive glass containing a layer of carbon in its surface. The different samples of conductive glass presented electric resistance of 3,77 â 8,00 Ω/□ and transmittance around 60% with wave lengths of λ ≥ 600nm. The TiO2:Ag layer applied presented a 30 μm thickness. With the exposure to sun light an electric current of 60,5 μA and a tension of 20,7mV was verified

The diploma thesis is dedicated to the exploitation of sulphonated polystyrene nanofibres as ion exchange nanomaterial. Ion exchange capacity of these nanomaterials has been determined by titration method and AAS. The effect of sulphonation on photophysical, photooxidative and photocytotoxic properties of sensitizer 5,10,15,20-meso- tetraphenylporphyrin (TPP) encapsulated in polystyrene nanofibres has been studied as well. Properties of TPP have been examined with time-resolved spectroscopy, photooxidation of uric acid as substrate and bactericidal tests on Escherichia coli DH5α with pGEM11Z plasmid. It has been discovered that following the sulphonation of the nanofabrics, the encapsulated sensitizer is partly present even in aggregation form. The polystyrene nanofabrics with encapsulated sensitizer keep its bactericidal efficiency also after sulphonation.

This study is dedicated to characterisation of photosensitisation properties of polymeric nanofibres with encapsulated photosentisitiser. Main goal of thesis is demonstration and study of H2O2 photoproduction. Photosensitizer used in this study was 5,10,15,20-meso-tetrafenylporfyrin (TPP), studied were also its complexes with Cu2+ a Ni2+ . Properties of nanofibers were examined using UV-Vis molecular absorption spectroscopy, fluorescence spectroscopy and electron microscopy (SEM).

The American public is bombarded with chemically fragranced products every day, typically in combination with each other. These products can include cosmetics, perfumes, detergents, air fresheners, soaps, and deodorants. Contained in these fragranced products are chemicals that can be harmful to child health and development. Many articles have been published examining the chemicals found in fragranced products and the effects that these chemicals can have on the human body. This integrated literature review examines empirical evidence related to the health and safety of particular chemicals used in these products. Nurses need to be aware of the actual and potential harms from the chemicals used in the self-regulating cosmetic industry and can advocate for public policies that promote a safer environment, therefore protecting the health and wellbeing of children.

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This dissertation focuses on the design, synthesis, and characterization of a variety of organic dyes, semiconducting materials, and surface redox-active modifiers of potential interest to organic-based emerging photovoltaics. A discussion of the materials’ optoelectronic properties, their ability to modify and promote electron transfer through an organic/transparent conducting-oxide interface, and finally their effect on the photovoltaic properties of devices utilizing them as light-harvesters is provided where relevant. The first two research chapters discuss mono-chromophoric asymmetric squaraine-based sensitizers and covalently linked, dual-chromophoric, porphyrin-squaraine sensitizers as light absorbers in dye-sensitized solar cells (DSSCs), in an attempt to address two problems often encountered with DSSCs utilizing this class of near infra-red sensitizers; The lack of panchromatic absorption and aggregation on the surface. Also, this dissertation discusses the design and synthesis of asymmetric perylene diimide phosphonic acid (PDI-PA) redox-active surface modifiers, and reports on the electron-transfer rates and efficiencies across the interface of an ITO electrode (widely used in organic-electronic devices) modified with these perylene diimides. Finally two series of hole-transport materials based on oligothiophenes and benzodithiophenes are reported: optoelectronic properties and preliminary performance of organic photovoltaic (OPV) devices fabricated with them is discussed.

This thesis gives a detailed description of the design and synthesis of new organic sensitizers for Dye sensitized Solar Cells (DSCs). It is divided in 7 chapters, where the first gives an introduction to the field of DSCs and the synthesis of organic sensitizers. Chapters 2 to 6 deal with the work of the author, starting with the first publication and the other following in chronological order. The thesis is completed with some concluding remarks (chapter 7). The DSC is a fairly new solar cell concept, also known as the Grätzel cell, after its inventor Michael Grätzel. It uses a dye (sensitizer) to capture the incident light. The dye is chemically connected to a porous layer of a wide band-gap semiconductor. The separation of light absorption and charge separation is different from the conventional Si-based solar cells. Therefore, it does not require the very high purity materials necessary for the Si-solar cells. This opens up the possibility of easier manufacturing for future large scale production. Since the groundbreaking work reported in 1991, the interest within the field has grown rapidly. Large companies have taken up their own research and new companies have started with their focus on the DSC. So far the highest solar energy to electricity conversion efficiencies have reached ~12%. The sensitizers in this thesis are based on triphenylamine or phenoxazine as the electron donating part in the molecule. A conjugated linker allows the electrons to flow from the donor to the acceptor, which will enable the electrons to inject into the semiconductor once they are excited. Changing the structure by introducing substituents, extending the conjugation and exchanging parts of the molecule, will influence the performance of the solar cell. By analyzing the performance, one can evaluate the importance of each component in the structure and thereby gain more insight into the complex nature of the dye sensitized solar cell. / QC 20110505

<p dir="ltr">In response to the ongoing global energy crisis, significant efforts have been made to enhance the efficiency of energy conversion devices that utilize renewable resources. This has spurred the development of multi-component semiconductors, which combine the strengths of both organic and inorganic materials to offset their individual limitations. This dissertation investigates advanced band engineering strategies to manipulate photophysical phenomena in these hybrid systems for specific applications. By focusing on two-dimensional perovskites and heterostructures formed from transition metal dichalcogenides and organic molecules, we explore how the inorganic components can sensitize their organic counterparts, examining the charge and energy transfer processes occurring at their interfaces and giving rise to unique excited states with diverse optical properties which hold significant potential for energy harvesting technologies.</p><p dir="ltr"><b>CHAPTER 1</b> furnishes readers with extensive insights into the semiconducting materials discussed in this dissertation, along with essential knowledge of fundamental concepts (such as excitons, charge and energy transfer, singlet fission, Marcus Theory, etc.) crucial for a deeper understanding of subsequent chapters. It also highlights the unresolved questions addressed later in this dissertation.</p><p dir="ltr"><b>CHAPTER 2 </b>provides a comprehensive overview of the spectroscopic and other characterization techniques used to study these materials.</p><p dir="ltr"><b>CHAPTER 3 </b>illustrates how the relative band alignment and coupling between the organic and inorganic layers of 2D perovskites impact the rates and dynamics of the transfer of triplet excitons across the hybrid interface. It also demonstrates how one can utilize extremely fast triplet transfer times to induce rapid photon upconversion in the perovskite, facilitated by doping of the organic layer. Triplet energy transfer driven photon upconversion is a promising method for enhancing the efficiencies of solar cells; therefore, this chapter makes a stride towards contributing newer insights for optimizing solar energy conversion.</p><p dir="ltr"><b>CHAPTER 4</b> focuses on how tuning the dimensionalities of 2D perovskites can modify their energy landscapes and further impact the interfacial photophysics, leading to the creation of long lived and mobile ‘interfacial’ excitons with enhanced electro-optic properties, promising for potential applications in solar cells and quantum computing.</p><p dir="ltr">In <b>Chapter 5</b>, the focus shifts to organic molecules that can undergo singlet fission, which are sensitized by highly absorbing monolayer transition metal dichalcogenides (TMDCs). This chapter explores how to induce intense emission from triplet pairs of the organic molecules — the critical yet elusive intermediate species in singlet fission, by engineering direct energy transfer into them from the TMDCs. Singlet fission-based technologies hold the potential to significantly enhance solar cell efficiencies, driving extensive research into optimizing the behavior of multi-excitonic triplet pairs. These triplet pairs offer the exciting possibility of multiphoton emission and/or the donation of multiple electrons (or excitons) in a single step. Our work aims to advance the understanding of these prospects and contribute to their practical application.</p><p dir="ltr"><b>CHAPTER 6 </b>summarizes the key findings from the previous chapters and explores potential future research directions. This dissertation, as a whole, contributes to and paves the way for further investigation into optimizing band engineering-based functionalities in 2D organic-inorganic semiconductors. These efforts aim to advance photophysical applications focused on improving energy conversion for a cleaner, more sustainable future.</p>